Here we show, by combining non-equilibrium molecular dynamics and continuum simulations, that rigid nanoplatelets can attain a stable orientation for sufficiently strong flows. Such a stable orientation is in contradiction with the rotational motion predicted by classical colloidal hydrodynamics. This surprising effect is due to hydrodynamic slip at the liquid-solid interface and occurs when the slip length is larger than the platelet thickness; a slip length of a few nanometers may be sufficient to observe alignment. The predictions we developed by examining pure and surface-modified graphene is applicable to different solvent/2D material combinations. The emergence of a fixed orientation in a direction nearly parallel to the flow implies a slip-dependent change in several macroscopic transport properties, with potential impact on applications ranging from functional inks to nanocomposites.The large-scale processing of nanomaterials such as graphene and MoS Current theories predict that a plate-like particle rotates continuously in a shear flow. Kamal et al. instead show that even nanometric hydrodynamic slip may induce a thin plate-like particle to adopt a stable orientation, and discuss implications of this effect for flow processing of 2D nanomaterials. Made of one or a few layers of atoms, they show physical properties not accessible with bulk materials2. In particular, charge and heat transport confined to a plane display unusual behaviour3, making two-dimensional (2D) appealing candidates for many applications in fields such as electronics4, energy generation and storage5, or in biomedicine6. But the industrial use of two-dimensional materials requires the understanding of the behaviour of suspended particles in liquids, as some of the most remarkable applications of two-dimensional materials involve their processing with fluids in at least some stages of the production process7. Control over the dynamics of suspensions of 2D materials would allow for the development of advanced materials8, including new-generation nanocomposites9 and functional inks10. In order to predict the behaviour of suspended two-dimensional materials, it is tempting to apply the classical toolbox of colloidal hydrodynamics11. But these materials, with their nanometric thickness and unusual interfacial properties12, challenge the very basic assumptions current colloidal hydrodynamics models rely on. New theoretical tools accounting for the specific properties of 2D nanomaterials are needed.Many inorganic two-dimensional materials have been isolated in the past years, including graphene, Molybdenum disulfide  is enhanced by up to an order of magnitude as compared to classical predictions22. Therefore it is natural to reconsider Jeffery’s predictions in the context of nanoplatelets with hydrodynamic slip suspended in water. It is currently unclear what effects may arise in suspensions due to slip.The study of two-dimensional materials is complicated by their unusual interfacial properties. Recent studies highlight the importance of hydrodynamic slip at the interface between water and an atomically smooth surface24 (Supplementary Note 1). A similar effect has been predicted for elongated particles of moderate aspect ratio (b/a ~ 0.5) and small slip length (λ ~ a/10)25, as well as for slightly oblate spheroids with b/a = 5/6, λ/a ≤ 1, and their longer axis perpendicular to the plane of the flow26. The effect of slip on the hydrodynamic torque and drag of rotating or settling elongated particles in quiescent fluid has also been studied31, as well as for plate-like geometries of relatively large thickness32. But nanoplatelets, made for example of carbon, BN, or MoS2, can exhibit extreme aspect ratios  and can have significant slip lengths, often larger than the nanoplatelet thickness. The effect of slip in such conditions must be reconsidered.In the context of colloidal hydrodynamics, slip is known to reduce the hydrodynamic stress applied by the shearing liquid on the particle’s walls, resulting, e.g., in a slowing down of the rotational dynamics of spheres and infinite cylinders with axis in the vorticity direction13, which predicts no stable orientation, fails to describe the rotational dynamics of graphene in the presence of comparatively large slip. In our simulations, the particle attains a stable orientation rather than performing periodic orbits. This unexpected result is due to a unique combination in our system of an extremely small effective thickness of the particle (~0.5 nm for single graphene layer33) and a significant slip at the graphene-water interface (λ ≥ 10 nm). The theory relies on a combination of slip and geometry, and is therefore not limited to water and graphene. In addition, using asymptotic methods, we are able to develop a continuum-based theory that accurately predicts the MD data. We also extend our MD results to systems other than pure graphene in water. We first consider a graphene-oxide platelet, with both edge and basal plane oxidation. Results show a transition from a stable orientation regime to a regime in which the particle rotates for a certain degree of basal plane oxidation. In addition, results obtained with non-aqueous solvents are qualitatively consistent with the predicted slip-induced alignment. More broadly, our results suggest that even nanometric slip lengths can change the rotational dynamics of a large class of 2D nanomaterials and solvents.In the present work, using a combination of Molecular Dynamics (MD) and Boundary Integral (BI) simulations, we demonstrate that in the case of graphene in water, slip induces a dramatic change in the rotational behaviour that goes beyond a simple slip-dependent change in rotational velocity. In particular, we show that Jeffery’s theory34. In these simulations, the particle is rigid and free to rotate. The platelet consists of a stack of n graphene layers of approximate dimensions 3.4 nm along 35. The thickness of the platelet is 2b, the length 2a, and the spanwise dimension of the computational domain in the w  nm (see Methods). Water molecules are maintained at a constant temperature T = 300 K using a Nosé-Hoover temperature thermostat39 applied only to degrees of freedom in the −1. More details concerning the MD simulations are given in the Methods section.We perform MD simulations of a freely suspended graphene particle in a shear flow using LAMMPSmentclass2pt{minimmentclass2pt{minimn = 2 free to rotate around the 13, we observe that the platelet rotates in the opposite direction, and reaches a time-average equilibrium angle αc ≈ 20° , where kB is the Boltzmann constant and T the temperature16), the stable equilibrium angle is associated with the hydrodynamic stress distribution over the platelet surface and its moment, the hydrodynamic torque. In contrast, MD simulations of a platelet presenting a no-slip surface produce orbits similar to those predicted by Jeffery , counter-clockwise (for T > 0), or reach a stable orientation (for T = 0). The data shows clearly a transition from T > 0 to T < 0 for a critical angle, which for a bilayer is αc ≈ 22° and for a monolayer is αc ≈ 18°, in good agreement with the dynamic simulations. The blue continuous curve in Fig. The key to understanding the rotational dynamics of a particle in a Stokes flow is the calculation of the hydrodynamic torque  it Fig. . The sigα < αc, we have calculated the hydrodynamic stress distribution over the particle surface when α = 0  is the distance from the reference surface to the platelet’s centreline, and dS is the element of surface area. We measure Δfs as function of s, with s = 0 in the centre of the platelet and s = ±a corresponding to the edges ges Fig. . The strges Fig. . If the Tn the torque due to the normal traction , because the tangential stress h(s)Δfs at the surface is reduced due to slip, Ts decreases by about one order of magnitude from the no-slip value  for a sufficiently large slip length  is clockwise regardless of the value of λ , and Tsm in Eq. ). When tlue Fig. d. But Tnlue Fig. c. This cgth Fig. . On the f λ Fig. . Hence t25. Our results instead demonstrate that the presence of even relatively small slip can qualitatively change the rotational dynamics of the platelet by perturbing the balance of tangential and normal torques  = 0, we getα = π/2, the slip length λ has a negligible influence on Tλ because the incoming velocity is directed almost perpendicular to the surface of the platelet, except at the edges. Thus, in analogy with the no-slip case,c1 is a positive constant. From BI calculations, c1 is found to be almost independent of the particle aspect ratio a/b, and approximately equal to c1 ≃ 6.6 for both n = 1 and n = 2  depends strongly on λ . We find that because fn acts perpendicularly to the boundary surface, the contribution to the torque from λ to leading order. The corresponding torque contribution is positive (counter-clockwise) and scales as 43. In contrast, the tangential traction depends strongly on λ, approximately asΔfs along the top surface of a bilayer as extracted from MD is Δfs/η) ≈ 0.05. This value compares well to the value of Δfs/η) = 0.06 given by Eq.  when λ/a ≪ 1. For the torque to change sign, the contribution to the torque from the normal traction must be larger than the corresponding contribution from the tangential traction. As anticipated before, when λ = 0, these two torque contributions cancel each other exactly to leading order. The clockwise torque predicted by Jeffery originates from the second-order torque term 43. For λ/a ≪ 1, λ to O(b/a), the leading order cancellation due to λ = 0, so that the remaining hydrodynamic torque comes from λ is of the order of b. This analysis can be repeated for objects of finite extent in the A brief quantitative explanation for Eq.  is the fαc can be obtained as follows. In the limit λ/a → ∞, Tλ(0) approaches a maximum value . Because Tλ(π/2) remains almost constant as λ/a → ∞, Eqs. (c ≈ 0.75 for c1 ≈ 6.6 and c2 ≈ 3.71). For example, comparing to the MD simulations given in Fig. λ/a ≈ 35, Eq. (αc ≈ 17° for n = 1 and αc ≈ 22° for n = 2. As λ/a increases the magnitude of Tλ(0) decreases , and the platelet will be practically aligned with the shear flow.An upper bound for lue Fig. . In thisentclass1pt{minima44. It may be argued that pure graphene is not easily dispersable in water. However, there are several possibilities to obtain a stable dispersion of graphene in water, such as modifying the graphene surface50, or adding dispersants to the solution52. In these situations, our theory is expected to apply as long as the slip length remains larger than the platelet’s thickness. Increasing graphene’s dispersibility will not necessarily alter the relevant hydrodynamic stress distribution at the particle surface. For example a selective modification of the edges of a graphene platelet can lead to an improved dispersibility50 without altering the slip at the basal surface.So far, we have focused on pure graphene in water because of the quality and quantity of available dataαc as compared with pure graphene .To illustrate the effect of edge-selective modification on the orientation of a graphene nanoplatelet in water, we have performed additional MD simulations using a monolayer graphene platelet presenting edge-selective oxidation (see Methods). The results show no significant change in the time-average equilibrium angle ene Fig. a. This i53. Therefore, increasing the degree of oxidation impacts the particle orientation: as the slip length λ decreases , the average angle αc decreases, in good agreement with our theory  or in cyclopentanone (CPO)54. We have performed MD simulations of freely suspended graphene particle using either NMP or CPO (see Methods). In both cases, a graphene platelet aligns at a small angle αc, while a no-slip platelet rotates as predicted from Jeffery theory . A criterion for the onset of deformability effects can be obtained by setting −1, and a solvent with viscosity η ~ 10−3 Pa s, any nanoplatelet with aspect ratio b/a < 10−5 will thus appear rigid.The theory represented here is based on the assumption that the nanoplatelet is rigid. For αc caused by Brownian forces is sufficiently small, our large-Peclet number theory provides a prediction of the time-average angle the particle will oscillate about, and is a starting point for predicting the full orientational particle distribution function for platelets in the presence of slip. Therefore, our results have implications for the rheology of graphene dispersions for a wide range of Peclet numbers.The effect of Brownian forces is to randomise the orientation. Provided that the angular dispersion about 60. It is clear that the transport properties of a mixture where the particles are aligned in an average sense with the flow are considerably different from the ones obtained when the particles are aligned with the flow at each instant. For instance, an atomically thin plate-like particle that is aligned instantaneously with the streamlines will disturb the flow very little, resulting in a smaller distortion of the streamlines, a smaller viscous dissipation, and hence a smaller suspension’s viscosity than if the particle was rotating16. Such decrease in viscosity, which could be relevant for improving the flowability of nano-inks, could be measured experimentally as a way to evidence slip effects (a similar suggestion was made in Kroupa (2017)24 for a concentrated dispersion of spherical particles). Another example of application of our findings is coating for gas barrier, where it is desirable to obtain a distribution of plate-like particles aligned with the boundary, so as to lead to a longer gas diffusion path61. We are suggesting that slip combined with shear can enable to achieve this objective.The importance of our result stems from the fact that changes in the orientation distribution of a particle will affect all the (effective) two-phase transport properties of a liquid dispersion 62), the change in microstructure of the liquid suspension will be inherited by the solid. In these applications, to obtain superior mechanical properties it is usually desirable to have almost complete alignment of the platelets63. Our results suggest that in the high-Peclet number limit all plate-like particles with λ > b will be nearly aligned with the flow, while for λ < b a larger variance is expected.Besides complex liquids, our result has implications for two-phase solid. In materials processing methods that involve the “solidification” of a continuous liquid phase containing nanoplatelets . Moving walls are used to enclose the fluid in the 68, for the atoms of the moving walls, LJ parameters are chosen to create a physically reasonable, idealised surface, with σww = 3.374 Å, where the index ‘w’ stand for ‘wall’, and a close-packed density of ϵww = 2.084 kcal mol−1 to create a hydrophilic surface characterised by a contact angle of a water droplet on these surfaces of ~55°, as measured in molecular dynamics simulations with the method employed by Werder et al.69. Periodic boundary conditions are used along the three orthogonal directions. Long-range Coulombic interactions were computed using the particle-particle particle-mesh (PPPM) method71. Fluid molecules are maintained at a constant temperature of 300 K with a Nosé-Hoover temperature thermostat39 applied only to degrees of freedom in the All simulations are performed with LAMMPS36 and the AMBER96 force field for the carbon-oxygen interactions, i.e., a Lennard-Jones potential with parameters ϵCO = 0.114 kcal mol−1 and σCO = 0.328 nm37. Water molecules are held rigid using the SHAKE algorithm72. A number N = 104 of water molecules is initially placed on a simple cubic lattice at the equilibrium density. The atmospheric pressure is imposed by imposing a normal force to the two moving walls. After  ~10 ps, the moving walls reach their equilibrium position at y = ±H/2, with H ~ 8 nm. Based on a preliminary convergence study, H and the size of the computational box along us = 200 m s −1 and us = −200 m s −1 are imposed on the top and bottom moving walls, respectively. This produces a shear rate a ~ 1.7 nm, the Reynolds number is η = 8.55 × 10−4 Pa s for TIP4P/2005 water model73. After a second equilibrium phase of 20 ps, we recorded the total forces applied on the graphene atoms for 4 ns. To remove the hydrostatic contribution to the force on the graphene atoms, we performed a simulation in the absence of shearing (us = 0). We then subtract the force profile obtained in presence of shearing with the force profile obtained in absence of shearing.We used the TIP4P/2005 model for waterα of the platelet is recorder as function of the time. Ten independent simulations were performed, from which the average value of α as well as the standard deviation were calculated.Parameters of dynamic simulations are identical to the static case, except that the rigid graphene nanoplatelet is free to rotate around the a = 1.7 Å. In order to build a realistic model of graphene oxide platelet, the reactive force field ReaxFF was used74. A total of four hydroxyl groups was added to each edge of the monolayer. When specified, a certain number of hydroxyl groups where also added to the basal plane at random location. A phase of relaxation at a temperature of 0 K allowed for the atoms to reach equilibrium positions. Finally, the final state of the graphene oxide platelet was frozen, and used as a rigid platelet for dynamic simulations in presence of solvent.A graphene oxide platelet was generated by the addition of hydroxyl groups (−OH) to a monolayer graphene platelet of initial half length σww = 3.374 Å, a close-packed density of ϵww = 2.084 kcal mol−168. The effective dimensions of a no-slip platelet are a ≈ 1.8 nm and b ≈ 0.37  nm.The atomic structure of no-slip platelet follows the calibrated surface and interaction parameters of a no-slip surface from Huang et al., with N-Methyl-2-pyrrolidone (NMP) and cyclopentanone (CPO). The initial structure of NMP and CPO molecules is extracted from the automated topology builder75. We use the all-atom Gromos force field for NMP and CPO76. Graphene-NMP, graphene-CPO, wall-NMP and wall-CPO interaction parameters are calculated using the Lorentz-Berthelot mixing rules.Two non-aqueous solvents were considered, respectively 77. In short, the position where the slip boundary condition applies is determined from the Gibbs dividing plane, and the slip length is extracted from a fit of the Poiseuille flow profile in the bulk region. Slip length value for water, NMP and CPO are given in the Table 78), and that the decrease of the slip length for increasing degree of oxidation is qualitatively consistent with results reported by Wei et al.53. Note also that in the case of multilayer graphene, the slip length along the edge of the platelet is expected to be smaller than on the basal plane due to the larger space between carbon atoms. Such space makes the potential energy landscape on the edges coarser than the potential energy landscape associated to the basal plane. A similar effect has been observed due to the intrusion of defect at the solid surface79.In order to measure the slip length from MD, we performed Poiseuille flow simulations of a liquid confined between two planes following the protocol by Herrero et al.ζ of the carbon atoms, which is the radius as ‘seen’ by the water molecules. Here, ζ is fixed by the parameters of the Lennard-Jones potential between oxygen and carbon atoms , and is ζ ≈ 2.5 Å33. The projection of the approximated graphene surface on the x − y plane can be parameterised asS.The boundary integral method is a computational method to solve the incompressible Stokes equation that requires a continuous surface onto which the integral equations are discretised. Examination of the molecular flow field indicates that a good approximation to the graphene surface is a rectangular parallelepiped with rounded edges Fig. . The hyda ~ 1.7 nm), the typical Reynolds number 41. We discretise the boundary integral equations on the reference surface S. In our case, the boundary integral equation for a point x ∈ S readsn is the surface’s normal and G and K are Green’s functions corresponding to the 2D ‘stokeslet’ and ‘stresslet’, respectively41. The formulation in Eq. (23; the slip velocity f via the Navier slip boundary condition:Δfs and Δfn and Owing to the small length scale of the graphene sheet in the MD system (Supplementary InformationPeer Review FileDescription of Additional Supplementary FilesSupplementary Movie 1


Simple estimations show that the thermoelectric readout in graphene radiation detectors can be extremely effective even for graphene with modest charge-carrier mobility ∼1000 cm The graphene radiation detectors promise to be fast and sensitive devices in a broad frequency band from sub-THz- to infrared spectrum of electromagnetic radiation, operational from ambient  to cryo f noise, scalable fabrication using CVD graphene, and undemanding electrical contacts. This combination of detector properties is particularly important for the fabrication of large detector arrays. The effectiveness of this readout stems from a high value of the Seebeck coefficient  coupling in graphene   and α4≈0W/(m2K4) . The secj. The current in real detectors is induced by the incoming radiation and is periodically varying with time t: Numerically solving Equation  gives T corresp/cm2 see . Ptot iss (see below).Because of a low hat T(x) c changes) curves a. The wishown in d. The ins is shown in s and is followed by a dramatic increase of ℜ at the expense of high s, the graphene channel is distinctly divided into three parts, p, neutral, and n  see . Of coureriments . However0101/cm2 . The temer mixer . Note, t00 K see .p-n junctions, especially for sufficiently uniform graphene with p-n junction would change much more dramatically than if only Joule heating were considered. This is also clear from the comparison between the first (Joule) and the second (Peltier) terms in Equation  the more asymmetric is the current through the junctions and the higher the responsivity can be expected [Even in GFET-based detectors, the TEP readout mechanism can contribute with a substantial, if not dominating, signal ,31. The Equation ), given ferences ,32 for rexpected . For graexpected , it is, The present work assumed that the current was applied through the metal electrodes while ignoring their contact resistances to graphene. The contact resistance can be sufficiently low for the edge contacts, which are possible for graphene encapsulated in both hBN  and Paryp-n junction are the main parameters that affect the detector performance most. In all cases, there is a trade-off between the responsivity and the total device resistance. Concluding, the thermoelectric readout in graphene radiation detectors represents a very competitive platform for building simple and sensitive direct detectors of radiation and arrays of them.The effectiveness of the thermoelectric readout mechanism in graphene radiation detectors has been estimated for a few key parameters, assuming a simple device geometry. The residual charge density and sharpness of the


Sarcoidosis is a granulomatous disease histologically characterized by non-caseating granulomas. Although it usually affects the lungs, it can affect any organ system and present with a wide variety of symptoms. Heerfordt-Waldenström Syndrome, or uveoparotid fever, is a rare form of sarcoidosis that presents with a combination of fever, parotitis, facial paralysis, and uveitis. In this case report, we demonstrate a rare manifestation of sarcoidosis in a patient who presents with both the aforementioned syndrome and cardiac involvement. This case serves to highlight the importance of identifying the various clinical manifestations and management of systemic sarcoidosis.  Sarcoidosis is a multi-organ inflammatory disease of unknown etiology. It is characterized by the deposition of non-caseating granulomas in various tissues, and patients are generally diagnosed early in adulthood, usually before the age of 50. The incidence and prevalence of sarcoidosis are highest in African Americans. The disease can affect multiple organ systems: musculoskeletal, respiratory, ocular, cardiovascular, gastrointestinal, lymphatic, and neurological systems . HeerforA 49-year-old African American male presented to the cardiology outpatient clinic for evaluation of recurrent syncope and palpitations. He had a one-month history of intermittent fevers with associated dry mouth and eyes. His physical examination revealed a bilateral parotid gland enlargement, cervical adenopathy, and facial nerve palsy, with eye redness. The patient's medical history was notable for longstanding hypertension. He had no known cardiac disease or neurological disorder. The initial electrocardiogram showed sinus rhythm with bifascicular block Figure . Brain nOn follow up cardiac magnetic resonance imaging (CMR), patchy late gadolinium enhancement (LGE) was appreciated in the septal wall and apical region concerning for cardiac sarcoidosis Figure . The patHeerfordt-Waldenström syndrome is a rare presentation of sarcoidosis characterized by enlargement of the parotid glands, facial nerve palsy, anterior uveitis, and fever. The clinical presentation varies from asymptomatic disease to acute illness, to chronic insidious organ failure. Facial nerve palsy is an integral component with an incidence of 25-50% in this syndrome. Parotid gland involvement occurs in about six percent and is usually bilateral. The majority have a low-grade fever. The involvement of the eye occurs in about 11-83% of patients, most commonly with anterior uveitis, along with increased lacrimation, photophobia, and blurred vision ). Taking these into consideration, the Heart Rhythm Society (HRS) Expert Consensus Recommendations on Criteria for the Diagnosis of Cardiac Sarcoidosis report two pathways to the diagnosis of cardiac sarcoidosis. The first involves the presence of non-caseating granuloma on histological examination of myocardial tissue with no alternative causes. The second pathway requires a histological diagnosis of extra-cardiac sarcoidosis along with one or more of the following: steroid-responsive cardiomyopathy or heart block, unexplained reduced left ventricular ejection fraction, unexplained sustained VT, high-grade heart block, patchy uptake on dedicated cardiac PET, late gadolinium enhancement on cardiac MR (CMR), and/or positive gallium uptake. It is important to note that other causes for the cardiac manifestations must have been excluded [While endomyocardial biopsy plays a role in the diagnosis of CS, the procedure has a low sensitivity of diagnosis due to the focal nature of the disease. When there is extra-cardiac sarcoidosis, the lymph node or lung biopsy provides a higher diagnostic yield with lower adverse outcomes and is often the preferred method to obtain a tissue diagnosis .Echocardiography is often the first imaging modality when suspecting CS. There are no pathognomonic findings, although nonspecific findings include regional wall motion abnormalities, dilated left ventricle, and impaired systolic or diastolic function. Right heart pressures can be elevated due to coexisting lung involvement. CMR is the next imaging modality when suspecting sarcoidosis with cardiac involvement. The main finding is the presence of late gadolinium enhancement (LGE), which indicates a component of fibrosis. The typical LGE pattern in a cardiac sarcoidosis patient involves the sub-epicardial and mid-wall LGE along the basal septum and/or inferolateral wall. CMR can also detect right-sided ventricular dysfunction, which can be due to elevated right heart pressures from pulmonary sarcoidosis or right ventricular granulomatous infiltration. Nuclear imaging with 18F-FDG PET has emerged as an important diagnostic imaging modality in CS. The imaging interpretation requires combining a resting perfusion scan and an 18F-FDG PET scan. The findings can be described: normal, early-stage, progressive disease, and fibrous disease . In addiThe treatment of systemic sarcoidosis most commonly has been corticosteroid therapy. The optimal dose of corticosteroid therapy for CS or Heerfordt-Waldenström syndrome is not known. Generally, the starting dose is 60 mg/day of prednisone, with a gradual reduction to a maintenance level of 10 to 15 mg/day over one year. Corticosteroid treatment will usually lead to the resolution of facial nerve palsy, uveitis, and parotid gland swelling . AlternaSince sudden death may be the first sign of cardiac sarcoidosis, electrophysiological studies to detect any conduction delays or increased risk of sustained arrhythmias should be strongly considered in patients with suspected cardiac sarcoidosis. Pacemakers are placed for complete heart block, and an implantable cardioverter-defibrillator (ICD) is placed for ventricular fibrillation or tachycardia and markedly reduced ejection fraction .This clinical case illustrates that despite the various manifestations of systemic sarcoidosis, early diagnosis using a multimodality approach can facilitate early treatment and symptom resolution. The systemic manifestations of sarcoidosis are numerous, and the diagnosis of both CS and Heerfordt-Waldenström syndrome require a high degree of clinical suspicion. Heerfordt-Waldenström syndrome was diagnosed in our patient based on clinical symptoms including fevers, dry eyes and mouth, bilateral parotid gland enlargement, cervical adenopathy, and facial nerve palsy. Per the HRS expert Consensus Statement, our patient met the criteria for CS based on a histological diagnosis of extra-cardiac sarcoidosis (submandibular lymph node biopsy) along with late gadolinium enhancement on CMR. Both manifestations revealed a very favorable treatment response to a gradual corticosteroid taper. To date, there are few case reports described in the literature of Heerfordt-Waldenström Syndrome with concomitant cardiac sarcoidosis. The association and implications of cardiac sarcoidosis with other types of sarcoid requires further investigations. Additionally, testing for treatment response with post treatment imaging has not been well established, but may a reasonable option to monitor response and disease activity.


To develop a synthesis technique providing enhanced control of graphene film quality and uniformity, a systematic characterization and manipulation of hydrocarbon precursors generated during plasma enhanced chemical vapor deposition of graphene is presented. Remote ionization of acetylene is observed to generate a variety of neutral and ionized hydrocarbon precursors, while in situ manipulation of the size and reactivity of carbon species permitted to interact with the growth catalyst enables control of the resultant graphene morphology. Selective screening of high energy hydrocarbon ions coupled with a multistage bias growth regime results in the production of 90% few-to-monolayer graphene on 50 nm Ni/Cu alloy catalysts at 500 °C. Additionally, synthesis with low power secondary ionization processes is performed and reveals further control during the growth, enabling a 50% reduction in average defect densities throughout the film. Mass spectrometry and UV-Vis spectroscopy monitoring of the reaction environment in conjunction with Raman characterization of the synthesized graphene films facilitates correlation of the carbon species permitted to reach the catalyst surface to the ultimate quality, layer number, and uniformity of the graphene film. These findings reveal a robust technique to control graphene synthesis pathways during plasma enhanced chemical vapor deposition. Currently, most high quality, large area graphene is produced via chemical vapor deposition (CVD) techniques with gaseous hydrocarbon precursors, micrometer scale Cu as a catalyst and support, and synthesis temperatures in excess of 900 °C ,2,3,4,5.This report demonstrates a unique methodology to gain in-depth understanding of the synergistic relationships between critical growth parameters. This investigation was carried out using a PECVD synthesis technique in which the size and ionization state of carbon precursor molecules reaching the growth catalyst is manipulated to reduce the rate of nucleation and absorption into the catalyst bulk, resulting in the formation of a continuous few-to-monolayer graphene film at 500 °C. This is achieved through control of the inlet between a remote inductively coupled plasma (ICP) location and the catalyst location that enables both ion screening and secondary capacitively coupled plasma (CCP) generation. This precursor screening technique is demonstrated on a 50 nm thick Ni/Cu catalyst (2 wt% Cu), representing a 10-fold reduction in catalyst thickness compared to previously published results, while eliminating the elevated temperature pre-growth anneal required by previous reports . Charact−7 torr is primarily H2O and CO2. Introduction of C2H2 and H2 results in an expected increase in 1 and 2 carbon species while ignition of a 20W plasma at the remote ICP location results in the generation of 3 and 4 carbon species, in agreement with previously reported characterizations of acetylene plasmas [All experimental results were obtained in custom-built reactor as shown in  plasmas ,28,29. F−6 torr which is connected to the main chamber through a leak valve.UV-Vis characterization was performed through spectrum collection  of ICP and CCP signals through isolated viewports, above the ICP and on the main chamber for CCP. Stage current characterization was performed through Pico ammeter  monitoring of the sample stage. Mass spectrometry  was collected in a secondary chamber with differential pumping to maintain 1 × 102 wafers through magnetron sputtering  of 48 nm Ni followed by 2 nm Cu without breaking vacuum. This catalyst composition and thickness was identified through preliminary experimentation to minimize catalyst dewetting during synthesis, observed as thickness is reduced, and enable graphene formation, difficult with increased Cu concentrations, without significant multilayer formation, common with reduced Cu concentrations [−7 torr followed by heating to 500 °C under 15 sccm of H2, resulting in a chamber pressure of 50 mTorr. To promote cleaning and alloying of the catalyst, the 1 cm × 1 cm sample was held at 500 °C for 2 min under H2 flow prior to introduction of the hydrocarbon precursor. Graphene growth was initiated by introduction of C2H2 at 0.1 sccm and ignition of a 20W ICP plasma for 1 min. Screening bias and secondary CCP were applied according to the desired synthesis regime through a −40 V bias application  to the first inlet plate or CCP generation at 2.5W  with a negative bias applied to the second plate. After preliminary experimentation, a −40 V screening bias was identified as optimal to stop all detection of current at the sample location without plasma ignition or arcing at the screening location during the synthesis processes. Following completion of the synthesis regime, ICP, CCP, and screening bias powers were set to zero, as well as the C2H2 flow rate. Finally, the sample was allowed to cool under 15 sccm H2 until 150 °C over approximately 15 min before venting the chamber to atmosphere.50 nm Ni/Cu catalysts were deposited on Si/SiOtrations ,31. Grap3 to etch both Ni and Cu until the graphene/PMMA floated to the surface. Following 5 rinses for 1 min each in DI water, the graphene with PMMA support was transferred to fresh Si/SiO2 and PMMA was removed in acetone. Raman characterization was performed on a Jobin Yvon HR800  with 532 nm laser excitation and mapping acquisition capabilities through a motorized sample stage. Raman map characterization and spectrum averaging were performed through in-house software, written in R, to peak fit D, G, and 2D bands for each spectrum collected and generate 2D plots.Graphene was transferred from the catalyst through spin coating  300 nm polymethyl methacrylate (PMMA) support and baking in air at 150 °C for 5 min. The sample was submerged in 0.5 M FeCl2D/G, and defect densities increase with increasing ID/G. While pristine monolayer graphene displays a nearly undetectable ID/G and an I2D/G ≥ 2, when defects are present monolayer graphene is identified by an I2D/G > 1 and FWHM2D < 100 cm−1 [2D/G are presented with color scales fixed between 1 and 2, with black areas, I2D/G ≤ 1, representing multilayer portions of the film, white areas, I2D/G ≥ 2, representing low defect density monolayer portions of the film, and orange areas, 1 < I2D/G < 2, representing few-to-monolayer portions of the film. 2 I2D/G Raman maps, with accompanying average Raman spectra for the mapped areas, of samples synthesized with and without an applied screening bias at the inlet plate, respectively. It is observed that with the application of a screening bias, both average layer number and areas of multilayer (areas with I2D/G ≤ 1 indicated by black portions of the Raman map) are reduced compared to the unscreened case by 62%. The reduction of multilayer portions of the film under the applied bias condition is attributed to the screening of high energy ions that are more readily dehydrogenated and adsorbed into the catalyst bulk, leading to rapid saturation and multilayer formation upon cooling. While these ions are screened by the applied bias, the neutral molecules, including 3 and 4 carbon species  generated in the remote plasma, are permitted to reach the catalyst location and participate in graphene formation at the catalyst surface. Though a significant reduction in multilayer portions is observed, the graphene film remains highly defective. The films  can be synthesized on 50 nm Ni/Cu thin film catalysts at 500 °C, without the need for any high temperature catalyst pretreatments. This technique represents not only an avenue for continued reduction to synthesis temperature and transition metal catalysts thickness requirements but reveals a novel method for active species control in broader PECVD synthesis techniques.In summary, we have demonstrated graphene synthesis techniques utilizing in situ manipulation of carbon precursors generated during plasma enhanced chemical vapor deposition to achieve continuous graphene films at reduced temperatures on reduced catalyst thicknesses. This experimental approach has allowed us to gain an in-depth understanding of the correlation among the parameters investigated. Moreover, this synthesis technique, which is not represented in literature, enables the manipulation of nucleation density, layer number, and defect densities though control of carbon precursor sizes and ionization states. Screening bias application between a remote ionization location and the sample location facilitates targeting of larger neutral molecules while a secondary ionization event can increase the reactivity of these molecules. Our results demonstrate that by utilizing this technique a few-to-monolayer graphene (with average Raman D to G peak intensity ratio I


Combining the quantum optical properties of single-photon emitters with the strong near-field interactions available in nanophotonic and plasmonic systems is a powerful way of creating quantum manipulation and metrological functionalities. The ability to actively and dynamically modulate emitter-environment interactions is of particular interest in this regard. While thermal, mechanical and optical modulation have been demonstrated, electrical modulation has remained an outstanding challenge. Here we realize fast, all-electrical modulation of the near-field interactions between a nanolayer of erbium emitters and graphene, by in-situ tuning the Fermi energy of graphene. We demonstrate strong interactions with a  >1000-fold increased decay rate for  ~25% of the emitters, and electrically modulate these interactions with frequencies up to 300 kHz – orders of magnitude faster than the emitter’s radiative decay (~100 Hz). This constitutes an enabling platform for integrated quantum technologies, opening routes to quantum entanglement generation by collective plasmon emission or photon emission with controlled waveform. Here, the authors realize fast, all-electrical modulation of the near-field interactions between a layer of erbium emitters and graphene, by in-situ tuning of the graphene Fermi energy. They obtain strong interactions with a  >1000-fold increased decay rate for about 25% of the erbium emitters, and electrically modulate these interactions with frequencies up to 300 kHz. FP up to 1000 for emitters in the near-field of metallic nano-antennas1. Such systems, however, do not easily allow for active modulation of the emitter–environment interactions. Active and dynamic control of emitter–environment interactions has been achieved in photonic crystal cavities and nano-electromechanical systems through modulation of the effective refractive index of the environment, using electromechanical actuation2, mechanical oscillations4, or photoexcitation of free carriers5. These techniques, however, either only work with one fixed modulation frequency or require optical fields for fast modulation. Furthermore, the achieved decay-enhancements are typically moderate, with FP ~ 10.One of the major accomplishments of nanophotonics research is the accurate control of the near-field interactions between light emitters and their environment. These interactions typically lead to a modification of the decay rate and emission properties, with decay-enhancement factors 6) with strong near-field light–matter interactions. Graphene not only provides a wide range of electrical tunability through its Fermi energy. At sufficiently high Fermi energy, it supports plasmons with much stronger field confinement than noble metals: the wavelength of graphene plasmons λpl is  ~100 times smaller than that of free-space photons λ0, whereas in metallic thin films λ0/λpl is typically <3, see ref. 7. For pristine graphene, this leads to a mode volume confinement of 8. Moreover, it is possible to reach a mode volume confinement up to 109 in graphene-metal grating structures9 and 1010 in cube-grating structures10, with potential for very strong near-field interactions with nearby emitters. Many suggested plasmon-based technologies, where the fields of photonics and electronics merge12, would benefit from fast temporal control of emitter–plasmon interaction, including applications such as single-photon nano-antennas13, and sub-diffraction-limited sensors14. Experimentally, however, active electrical tunability of emitter–graphene interaction has only been demonstrated with low decay-enhancement (FP <  3) and in a non-dynamic fashion16.An effective solution can be found in graphene, a two-dimensional (2D) material that combines a high degree of electro-optical tunability at high speeds . Rare-earth erbium ions are technologically highly relevant as they emit photons at 1.54-μm wavelength, within the C-band of optical communication systems. Furthermore, rare-earth oxide crystals have a proven relevance in photonic quantum memories2O3 (2%). To achieve strong near-field interactions, the erbium emitters should be located at nanoscale distances from the 2D material—ideally within the sub-wavelength volume occupied by the highly confined plasmons (<15 nm). A sufficiently thin layer with erbium emitters is therefore required. However, crystals of nanoscale dimensions typically suffer from detrimental non-radiative losses due to surface defects25. Removing this loss mechanism is crucial, as it constitutes a competing energy flow channel for erbium–graphene interactions that would hinder the observation of these interactions. We overcome this experimental bottleneck by using atomic layer deposition (ALD)26 with optimized post-treatment—a technique that produces few-nanometer-thick rare-earth-doped Y2O3 films with atomic scale thickness control and emission quality as in bulk crystals  and  >1000 in the interband regime (EF = 0.3 eV). In order to observe these regimes experimentally, we excite the erbium ions with a 532-nm laser and detect their emission at 1.54 μm in a scanning confocal microscope (see “Methods”), while varying the Fermi energy using the topgate. Figure 4 W cm−2) to ensure that the ion transition is not saturated , energy transfer is mostly caused by interband transitions in graphene. Above 0.4 eV, interband transitions become suppressed by Pauli blocking, because EF > EEr/2, and intraband transitions become the dominant energy decay pathway of the ions. The positive slope of the emission contrast for EF > 0.6 eV is a clear signature of the presence of plasmons. The slope is positive because the decay length of the plasmon field is approximately the same as the plasmon wavelength, λpl, which scales linearly with EF. Therefore, as EF increases, the volume occupied by the plasmon field increases, thus increasing the number of ions interacting with plasmons, and thereby decreasing the amount of emitted light.The intraband and interband absorption regimes can be experimentally distinguished because they are associated with different local densities of optical states (LDOS), leading to distinct decay rates for the emitters interacting with graphene. Our calculations following refs. e EF = 0. eV. In oEF ~ 0.2 eV) and for the intraband regime (EF ~ 0.8 eV), as well as in a region without graphene. We observe faster decay in the intraband regime (e−1 time of  ~3 ms) and even faster decay in the interband regime (e−1 time of  ~1 ms), compared to the decay without graphene (e−1 time of  ~6 ms), in qualitative agreement with the emission contrast measurements, which show less emission in the interband regime than in the intraband regime.To obtain more insight into the dynamics of the erbium–graphene interactions, we measure the erbium emission decay curves. We modulate the excitation laser into pulses and use single-photon counting electronics to create emission histograms (see “Methods”). Figure γ of the emitters, depending on their distance to graphene z, since γ scales with z−4 in the interband regime and with 30. The ions located furthest away from graphene have the lowest energy transfer rates, thus emitting more photons and extending the decay curves to long times. The strongly negative slope in the beginning of the decay curves  graphene-induced decay-enhancement FP, which is  ~7 (~2.5) in the interband (intraband) regime. This indicates that an overall fraction of η ≈ (FP − 1)/FP ≈ 85% (60%) of the energy of excited erbium emitters flows to interband (intraband) transitions in graphene. We note that we have reproduced these decay curves with multiple erbium–graphene samples , as these are the ions that emit the largest number of photons during lifetime measurements. On the other hand, the emission contrast measurements of Fig. FP , as these are the ions that transfer the highest fraction of their energy to graphene, leading to the largest decrease in emission. Together, the decay curves and emission contrast measurements yield the density of erbium ions as a function of z . In terms of the ion dynamics, the distribution P(γ) can be interpreted as the likelihood that a given ion decays with a certain decay rate γ. The inset of Fig. P(γ) is shifted toward higher values of γ in the regions of the device with graphene, indicating that the decay rate increases due to energy transfer to graphene. From the analysis of these decay-rate distributions, we extract the distribution of decay-enhancement factors P(FP), following the numerical procedure described in the “Methods” section. Then we convert P(FP) into the distribution of erbium–graphene distances P(z), i.e., the density distribution, by using the theoretical relation between FP and the emitter–graphene distance z.In detail, we extract the distribution for ions with P(FP) and P(z) obtained from the decay curves are accurate up to FP = 103, corresponding to z ≳ 7 nm. For higher values of FP, the decay is so fast and has such a small amplitude that we cannot resolve it experimentally in our decay curves , and find the ion density distribution P(z) that best reproduces the measurements of Fig. It turns out that the distributions P(z) with the density distribution measured by means of time-of-flight secondary ion mass spectrometry ,p. In this way, the cumulative distribution P(FP > p) provides the fraction of ions with FP > p. Using Eq. (FP > 10 for the interband (intraband) regime, and approximately 25% of ions have FP > 1000 for both regimes, which means that >99.9% of the energy from these ions flows to graphene.Importantly, our analysis of the experimental data of Fig. 31. We induce a fast temporal variation in the LDOS experienced by the emitters by modulating the Fermi energy of graphene. To this end, we apply an AC voltage to the backgate and verify the effect of this modulation on the excited state populations of erbium by measuring the temporal variations of photon emission using a single-photon counting set-up. In these experiments, we keep the excitation laser power constant. In Fig. Having established the occurrence of highly efficient erbium–graphene interactions in our system, we now demonstrate dynamic control of these interactions on a time scale that is much shorter than the emitter’s lifetime of  ~10 ms2O3 32.As In a second series of measurements, shown in Fig. N ions using the distribution of ion distances P(z) obtained from the emission contrast measurements and decay curves. For every ion i at distance zi, we numerically solve the rate equation with the time-dependent FP factor and for the corresponding Fermi energy modulation (see “Methods”). We find good agreement between experimental data and numerical simulations, which do not contain any freely adjustable fit parameters (see “Methods”), adding credibility to our computational approach. We note that, only in the case of Fig. We model the temporal modulation of photon emission by simulating the dynamics of 34. In particular, our hybrid erbium–graphene platform enables fast temporal control over the strong near-field interactions, thus providing an efficient way to manipulate quantum states in nanoscale solid-state devices by means of conventional electronics. The control over the dynamics of single-photon emitters on a much shorter time scale than their lifetime is an essential ingredient toward observing intriguing effects, such as Dicke phase transitions23, non-linear light–matter interactions at the quantum level35, and multi-particle entanglement generation24. In addition, such a fast control over the near-field interactions will expand existing functionalities of plasmonic nanodevices integrating graphene waveguides and cavities38. It enables the control of the waveform of photons and plasmons emitted into a guided mode39, which is a required capability for distributed quantum systems. It furthermore facilitates the connection of optical transistors41 based on quantum emitters in integrated plasmonic circuits, with the possibility to attenuate or amplify the plasmon emission by means of a gate voltage. These promising applications will be boosted by the prospects of coupling plasmonic modes to the far field through optical nanoantennas or through optical waveguides42, thus enabling controlled photon emission enhancement for optical communications. Overall, these prospects will stimulate the development of emitter–graphene interfaces as a building block for hybrid systems with applications in optoelectronic quantum technologies.We have demonstrated a material platform that integrates the optical properties of erbium quantum emitters with the strong near-field interactions of graphene, providing the conditions for quantum manipulation and metrological functionalitiesβ-diketonate precursors: Er(tmhd)3 and Y(tmhd)3. The precursors are held at 160 °C and delivered using N2 as a carrier gas and O3 as an oxidizing agent. The precursors are flown sequentially with 3-s injection time into the thermalized deposition chamber at 350 °C. The number of cycles is adjusted in order to obtain the desired thickness (circa 12 nm here). The films are annealed at high temperature (950 °C) for 2 h in air prior to measurement in order to improve crystallinity. More details about the optimization of the growth procedure are discussed in Supplementary Note 2O3:Er3+ layer using the standard wet transfer method. Graphene is patterned into a Hall-bar geometry by laser writing optical lithography and subsequent reactive ion etching , and directed into a near-infrared single-photon detector (ID Quantique id210) with very low level of dark counts (~9 Hz). For time-resolved measurements, emission histograms are obtained using photon-counting electronics (PicoHarp 300) in time-tagged time-resolved acquisition mode, recording the arrival times of all photons. During lifetime measurements, the excitation laser intensity is modulated into square pulses by switching on and off the signal of an acousto-optic modulator. All measurements were carried out at room temperature. We verified that, during measurements that can take up to several hours, the Fermi energy did not vary significantly , which provides a spatial resolution of  ~1 μm. A focused 532-nm laser beam, with typically a power of  ~0.2 mW at the sample, excites the ions into the short-lived state γEr = γed + γmd + γnr, where γed ~ 75 Hz and γmd ~ 50 Hz correspond to the electric and magnetic dipole moments, respectively31, and γnr represents the non-radiative decay channels of the erbium thin film. In the regions with graphene, the total decay rate is γ = γEr + γgr, where γgr is the rate of energy transfer to graphene. Every experimental decay curve, n(t), is described as a continuous sum of exponential decays, P(γ) is the probability distribution that describes the likelihood that a given ion decays at a certain rate γ. Here we have considered that the excited erbium population, and thus the emission, is inversely proportional to the decay rate. The integral has the form of a Laplace transformation, so we can extract P(γ) by inverse Laplace transformation using the numerical techniques of ref. 43  by numerically solving the convolution equation, PEr(γEr) denotes the decay-rate distribution in the regions of the device without graphene (we write the subindex Er to indicate that the distribution only includes the intrinsic decay mechanisms of the erbium film). In doing the deconvolution, we filter out the small effect of the undesired non-radiative decay channels γnr, thus obtaining the pure contribution of the erbium–graphene interactions, γgr. The distribution Pgr(γgr) can be easily converted into the distribution of decay-enhancement factors, P(FP), by using the relation γgr = (FP − 1)γed. Next, we translate P(FP) into the density distribution, P(z) = P(FP)dFP/dz. For this, the decay-enhancement factor as a function of distance, FP(z), is calculated as in refs. 29, where the response of graphene to the localized field of the emitter is simulated using the optical conductivity of the Kubo model, with a typical momentum scattering time of τsc = 50 fs and a refractive index of 1.8 for Y2O3 and 1.4 for the electrolyte . The positions zi ≳ 7 nm are obtained by discretization of the density distribution P(z) calculated from the decay curves. The positions zi ≲ 7 nm are free parameters that we vary to find the distribution of distances, FPγed + γmd + γnr), where the theoretical decay-enhancement factor FP(zi) is computed from the methods of refs. 29 (see above). Here we assume that γnr = 10 Hz for all ions (see Supplementary Note P(z), and vice versa, by integration and discretization, respectively. We typically use N = 50, where the density distribution already nicely converges.We use a computational model of , zi i = , ..., N.i of our N-ion model by numerically solving the rate equations44,zi, and γexc is the excitation rate, which depends on the excitation laser power. The results of the simulations do not depend on γexc since every measurement is normalized to its mean value, although we need to assume a certain value of γexc to do the computation. To calculate EF that corresponds to the applied gate voltages using the calibration described in Supplementary Note EF = BΔVbg, where B = 15 eV mV−1 (13 eV mV−1) in the experiments of Fig. EF into FP using the methods of refs. 29 (see above).We simulate the quantum-state population dynamics for every ion −9 mbar. A pulsed 25 kV Bi+ primary ion beam delivering 1 pA over a 100 × 100 μm2 area is used to etch the chemical species from the surface. The masses of the removed chemical species are determined by ToF-MS. The sputtering of the surface was done using a 2-keV Cs+ sputter gun giving a 100-nA target current over a 300 × 300 μm2 area. The interlacing between Bi+ and Cs+ guns allows to record TOF-SIMS depth profiles. We used the profile of the removed YO− particles to extract the Er3+ density distribution. This approximation is justified since the diffusion coefficients of yttrium and erbium are practically the same  to measure the density profile of the yttrium and erbium ions at a sufficiently low primary ion dose density to keep static conditions. The spectrometer was operated at a pressure of 10Supplementary InformationPeer Review File


In the UK, Gypsy, Roma and Traveller (GRT) communities are generally considered to be at risk of low or variable immunisation uptake. Many strategies to increase uptake for the general population are relevant for GRT communities, however additional approaches may also be required, and importantly one cannot assume that “one size fits all”. Robust methods are needed to identify content and methods of delivery that are likely to be acceptable, feasible, effective and cost effective. In this paper, we describe the approach taken to identify potential interventions to increase uptake of immunisations in six GRT communities in four UK cities; and present the list of prioritised interventions that emerged.This work was conducted in three stages: (1) a modified intervention mapping process to identify ideas for potential interventions; (2) a two-step prioritisation activity at workshops with 51 GRTs and 25 Service Providers to agree a prioritised list of potentially feasible and acceptable interventions for each community; (3) cross-community synthesis to produce a final list of interventions. The theoretical framework underpinning the study was the Social Ecological Model.Five priority interventions were agreed across communities and Service Providers to improve the uptake of immunisation amongst GRTs who are housed or settled on an authorised site. These interventions are all at the Institutional  and Policy (e.g. protected funding) levels of the Social Ecological Model.The “upstream” nature of the five interventions reinforces the key role of GP practices, frontline workers and wider NHS systems on improving immunisation uptake. All five interventions have potentially broader applicability than GRTs. We believe that their impact would be enhanced if delivered as a combined package. The robust intervention development and co-production methods described could usefully be applied to other communities where poor uptake of immunisation is a concern.Current Controlled Trials ISRCTN20019630, Date of registration 01-08-2013, Prospectively registered. In the UK, Gypsy, Roma and Traveller (GRT) communities are generally considered to be at risk of low or variable immunisation uptake. This is based on data demonstrating low uptake of preventive health services –4, the fThe barriers to uptake by GRT communities reflect two groups of influencing factors for immunisation uptake in the general population and high-risk groups –11, nameThese multiple, complex and often interlinked factors mean that a broad range of approaches at individual, provider, health system, and national levels are needed to ensure optimum immunisation uptake. Many strategies that are developed and evaluated for the general population –22 are rOur UNITING (UNderstanding uptake of Immunisations in TravellIng aNd Gypsy communities) study drew on the aforementioned guidance to systematically use evidence, theory, population segmentation and methods of co-production. It had two aims: (1) Investigate the barriers and facilitators to acceptability and uptake of immunisations amongst six GRT communities across four UK cities; (2) Identify potential interventions to increase uptake of immunisations in these GRT communities. The six communities were: Eastern European Roma and English Gypsy/Irish Traveller (Bristol), English Gypsy (York), Eastern European Roma and Scottish Showpeople (Glasgow), and Irish Traveller (London). The theoretical framework underpinning the study was the Social Ecological Model (SEM)  which reA modified intervention mapping process  using inWorkshops with GRTs and Service Providers to agree a prioritised list of potentially feasible and acceptable interventions for each communityCross-community synthesis to produce a final list of prioritised interventionsThis work was conducted in three stages see Fig. . Each stA modified intervention mapping approach  was usedTo generate as many potential interventions as possible, ideas were drawn from interviews with GRTs in the target community and their Service Providers, from interviews with GRTs from the other communities and their Service Providers, and from the knowledge and experience of the research team and advisory group. Two researchers independently mapped intervention ideas to the barriers, objectives, targets and SEM level and then jointly agreed the intervention ideas to take to the workshops. These fell into three categories: promoting awareness and understanding of immunisation, developing trust and respect, and improving immunisation services. The matrices produced for the first two communities (Bristol Eastern European Roma and Bristol English Gypsy/Irish Travellers) were used as a framework from which to build the matrices for the other communities, incorporating additional or adapted interventions based on the interviews. See Table The aim of the workshops was to “co-produce”  a priori1 = no difference to 5 = a lot of difference). This ranking did not consider the potential ease or difficulty of implementation and their potential influence on perceived impact). Participants were also asked to identify potential barriers and facilitators to the ideas working in their community. At the end of this session, GRTs and Service Providers had both drawn up a ranked list of intervention ideas based on these impact scores. GRTs and Service Providers then came together and a facilitated discussion, including further discussion on feasibility, was conducted to produce a jointly agreed, prioritised list of five feasible and acceptable interventions which could positively impact on immunisation uptake in their community. As an example, Table In each workshop, following the spoken presentation of the key findings from the interviews by the local researcher, a structured and facilitated two-step process  was usedEmerging findings from stages 1 and 2 clearly revealed shared rankings, concerns and potential solutions, across communities. For some interventions, high impact rankings were assigned by GRT participants across communities but not by the Service Providers. For others, the reverse occurred. Therefore, stage 3 involved looking across both the independent GRT and Service Provider (impact) rankings and final co-produced, prioritised lists of interventions from each workshop to identify the five most consistently well supported interventions. Interventions needed to be in the top six of the independent rankings by the GRTs and/or Service Providers to be included in the final list. Interventions that were strongly supported but only by particular, usually one or two, communities and their Service Providers were also recorded. These are reported elsewhere .At this stage a detailed description elaborated the nature of each intervention in accordance with the ‘modelling process and outcomes’ step in the MRC guidance on developing and evaluating complex interventions . This inFive interventions emerged as most consistently supported across GRT communities and/or their Service Providers to improve uptake of immunisation among GRT who are housed or settled on an authorised site see Fig. . The intDetail  for the five interventions are presented in Table In this paper, we describe the approach taken to identify potential interventions that could increase uptake of immunisation in GRT communities which are housed or settled on an authorised site. We present the five interventions that emerged as most consistently supported across GRT communities and/or their Service Providers. We reflect here on the identification process and consider its strengths, challenges, and limitations. We then discuss the interventions in the context of existing practice, policy and research.The key strength of our approach was that we used established methods for robust intervention development , 29, 38;It is important to consider how transferable the finalised list of interventions is to (1) other GRTs/Service Providers within these six communities and 2) other GRT communities in the UK. With respect to (1) we are confident the initial selection of intervention ideas (in stage 1) reflected wider community views as these were based on interviews with 174 GRTs across family roles and immunisation experiences; and 39 Service Providers in both frontline and strategic roles –14. As s other GRThe final five prioritised interventions were all “upstream” interventions  and focuInterestingly, these proposed interventions were not necessarily new, nor were they unique to the needs of GRTs. The UK 2010 Equality Act  and otheThe UK National Institute for Health and Care Excellence  and the The five prioritised interventions were Institutional and Policy level interventions, reinforcing the key role of GP practices, frontline workers and wider NHS systems on improving immunisation uptake. All five interventions have potentially broader applicability than GRT communities alone. The complementary nature of these interventions suggests that their impact would be enhanced if delivered as a combined package. Local implementation must reflect community differences. We have used robust intervention development and co-production methods which could usefully be applied to other communities where uptake of immunisation is a concern.


Both the timing  and amount  of language exposure affect language-learning outcomes. We compared speech recognition accuracy across three listener groups for whom the order (first versus second) and dominance (dominant versus non-dominant) of two languages, English and Spanish, varied: one group of Spanish heritage speakers  and two groups of late onset L2 learners (L1-dominant English/Spanish learners and L1-dominant Spanish/English learners). Sentence-final word recognition accuracy in both English and Spanish was assessed across three “easy” versus “difficult” listening conditions: (1) signal-to-noise ratio , (2) sentence predictability (high versus low sentence predictability), and (3) speech style (clear versus plain speech style). Overall, SHS English recognition accuracy was equivalent to that of the L1-dominant English Spanish learners, whereas SHS Spanish recognition accuracy was substantially lower than that of the L1-dominant Spanish English learners. Moreover, while SHS benefitted in both languages from the “easy” listening conditions, they were more adversely affected by  the presence of higher noise and lower predictability in their non-dominant L1 Spanish compared to their dominant L2 English. These results identify both a benefit and limit on the influence of early exposure. Specifically, the L2-dominant heritage speakers displayed L1-like speech recognition in their dominant-L2, as well as generally better recognition in their non-dominant L1 than late onset L2 learners. Yet, subtle recognition accuracy differences between SHS and L1-dominant listeners emerged under relatively difficult communicative conditions. However, in many immigrant communities , there is a growing number of speakers for whom their L1 is not their dominant language . For thi1 are not fully realized to dominant L1-like levels as SHS age and attend higher levels of education in English. This early, yet unsustained, exposure can then be compared to young adult learners of Spanish (approximately 18–19 years old) who receive several years of late exposure to Spanish . Although the current amount of use for English and Spanish is similar in heritage speakers versus L2 learners, the manner and timeframe in which the languages were acquired are not equivalent. Despite not being symmetrical (as the exposure to Spanish for SHS continues throughout adulthood), comparing L2 learners of Spanish to heritage speakers of Spanish isolates early, yet interrupted, L1 acquisition from exclusively late L2 acquisition.Since age-of-acquisition and language dominance are confounded in the typical L1-dominant bilingual individual, the “switched” dominance of L2-dominant heritage speakers provides a unique window into the separate and combined influences of early versus extended language exposure on speech and language processing. That is, comparing heritage speakers to adult L2 learners of the heritage speakers’ L1 distinguishes early versus late exposure in bilingual listeners, whose levels of knowledge of the target language appear equal, as many heritage speakers place into college-level intermediate language courses for their L1. See  and as aThe current study focuses on L1 and L2 speech-in-noise recognition at the sentence level with a particular focus on acoustic-phonetic and semantic-contextual factors (to be defined and discussed in detail below) that are known to influence L1 and L2 speech recognition: speech style, semantic predictability, and signal-to-noise ratio (SNR). As discussed further below, previous work has shown that some sources of speech recognition enhancement are highly beneficial for L1 speech processing but provide either no benefit or less benefit for L2 speech processing. In this study, we asked which, if either, of a switched-dominance (or heritage) speaker’s two languages would show non-dominant L2-like vulnerabilities in speech recognition, the non-dominant but first-acquired L1 or the dominant but second-acquired L2. The following section outlines the various factors known to influence speech perception.Clear speech refers to a slower, hyper-articulated speaking style that a talker uses in order to aid the listener in speech recognition e.g., . Cross-l2, listeners have been shown to benefit from semantic cues in speech-in-noise processing  has also been shown to affect L1 and L2 listeners differently. Specifically, L1, but not L2ng e.g., . That isng e.g.,  comparedMore recently, The presence of background noise is well known to lower a listener’s accuracy and to raise the effort needed to process speech effectively e.g., , who fouGiven these differences between L1 and L2 processing, the present study questions how signal and semantic-contextual enhancements affect L1 and L2 speech recognition for Spanish Heritage Speakers (L2-dominant) compared to late L2 learners (L1-dominant). We hypothesize that if early language exposure is sufficient for establishing dominant L1-like speech processing routines e.g., , then SHIn order to test the above hypotheses, we administered a speech-in-noise recognition task in both English and Spanish for a group of Spanish Heritage Speakers , as well as a group of L1-dominant English listeners learning Spanish and a group of L1-dominant Spanish listeners learning English. In this task, participants were asked to identify keywords embedded in sentence-final positions for an accuracy score in each language. Using linear mixed-effect models, we then compared the three-way interaction between listener group, signal manipulation , and task language to determine whether, if at all, the heritage speaker group patterned differently from either the L1-English/Spanish learner or L1-Spanish/English learner group. As the results will suggest, while early exposure to both languages played a crucial role in speech processing , heritage speakers typically benefitted from signal enhancements in English, the dominant L2, while being more adversely affected by signal degradation  in Spanish, their non-dominant L1.2.2.1.Participants consisted of three groups: L1-English Spanish learners (L1-E/SL), Spanish heritage speakers (SHS), and L1-Spanish English learners (L1-S/EL). Listeners in the L1-E/SL and SHS groups were explicitly required to have been placed into intermediate Spanish courses at the university level. There was no course placement requirement for L1-S/EL as the majority of this population was graduate students studying at Northwestern University. In each group, there were 12 listeners for a total of 36 listeners . In addition to Spanish course requirements, we established criteria (explained below) to determine which group participants should be placed in based on language acquisition and use. All listeners were compensated $10 an hour for their participation. Before beginning the study, participants were asked to fill out a brief form about their demographic information and language usage. The information about the participants reported below is based on these self-reported fields. Any percentages reported are based on participant group averages. All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Internal Review Board with approval IRB# STU00200566.L1-E/SL were defined as English L1-dominant speakers learning Spanish as their L2. The average age of L1-E/SL participants was 19.9 years old (standard error = 0.46). This group was dominant in English, as the average age of acquisition (AoA) for English was between 0 and 1 years old. The average AoA of Spanish for this group was 18 years old. Participants in the L1-E/SL group were recruited from intermediate Spanish classes at Northwestern University and on average reported using English 83.5% (standard error = 6.11) and Spanish 8.3% (standard error = 1.86) of the time. As these data indicate, the L1-E/SLs were heavily English dominant.SHS were defined as Spanish L1 speakers who grew up in a Spanish speaking home, but attended elementary school (and beyond) in the USA, where the medium of instruction was English. The average age of the SHS group was 19.7 years old (standard error = 0.36). The average AoA of Spanish for SHS was approximately 0 (birth) and ranged between 3 to 8 years old for English. Critically, SHS are English L2 dominant due to the heavy and prolonged use of English in school and the community. SHS also have fluent reading and writing skills in English based on their formal education in the USA in which the medium of instruction is English, but not necessarily in Spanish as evidenced by SHS participants being placed in intermediate level Spanish courses at Northwestern University on the basis of a Spanish language placement test. Further evidence that SHS are English dominant comes from their self-reported values of language use in both English and Spanish. SHS indicated on average that they used English 74.45% of the time (standard error = 5.1), while reporting that they use Spanish on average 21.58% of the time (standard error = 2.84).The L1-S/ELs were defined as Spanish L1-dominant speakers, who grew up in Latin America and attended high school where the medium of instruction was Spanish. The average age of L1-S/EL was 24.8 years old (standard error = 1.17). The average AoA of Spanish for L1-S/EL was approximately 0 (birth) and the average AoA for English was 11 years old. Evidence that L1-S/EL were clearly Spanish dominant comes from self-reported use of English and Spanish. L1-S/EL reported using English 32.3% of the time (standard error = 6.21), while Spanish use was 55% of the time (standard error = 6.64). All of the L1-S/EL speakers were graduate students at Northwestern University, so it is unsurprising that they would self-report a higher English use (their non-dominant language) compared to the SHS and L1-E/SL Spanish use at the time of testing.Additionally, the contexts in which Spanish and English are used differed across participants. We examined the self-reported contexts in which each listener group used Spanish and English. We found that whereas L1-E/SL and L1-S/EL generally had L2 usage restricted to classroom and colleague settings, SHS reported using Spanish primarily with parents, siblings, friends, and other relatives. These SHS language patterns are consistent with 3, which was given to each participant in both English and Spanish after speech recognition testing. The cloze test consisted of a passage with 40 blanks. Participants were instructed to fill in each blank as best they could to appropriately complete each sentence. The blanks in the cloze tests are designed to target specific syntactic , semantic, and pragmatic features in the language of the test. The cloze tests are not a measure of oral proficiency, but rather a measure of explicit grammatical knowledge in written Spanish and English. Spanish Heritage speakers (SHS) had significantly higher cloze proficiency than L1-E/SL in Spanish  = 2.55, p = 0.04), and there were no significant differences between L1-E/SL and SHS in English proficiency  = −1.13, p > 0.05). Comparing L1 Spanish speaking L1-S/EL to SHS, we also found significantly lower SHS Spanish cloze proficiency  = −4.1, p < 0.01) but higher SHS English cloze proficiency  = 2.36, p < 0.05). It is important to note that the SHS combined language proficiency (English plus Spanish proficiency = 37.5+35.5 = 73) substantially exceeds that of their L1-E/SL counterparts (English plus Spanish proficiency = 38 + 32.5 = 70.5) and is equivalent to that of the L1-S/EL counterparts (English plus Spanish proficiency = 33.5 + 39 = 72.5). The results of written proficiency in English and Spanish for all groups are shown in Proficiency in both languages for all participants was assessed with a written cloze test2.2.The materials for this study consisted of specially designed Spanish and English sentences each with a single keyword (60 keywords in Spanish and 60 keywords in English) in sentence-final position and the rest of the sentence  serving as the context. These sentences were presented to listeners in conditions that varied by use of three factors: speech style of the talker, predictability of the target word, and signal-to-noise ratio (SNR).4  such that the final keyword could be correctly guessed based on the preceding words. Sentence frames that were ‘low predictability’ contained no such contextual cues to the final word. All English stimuli were taken from pork.High contextual predictability: The meat from a pig is called pork.Low contextual predictability: Father thought about the High versus Low Contextual PredictabilityThe current study normed new Spanish stimuli (see below) on L2 Spanish learners following a similar protocol used in The third factor was signal-to-noise ratio (SNR), set at +5 dB (high) and 0 dB SNR (low) for each language. Studies, such as 2.2.1.Predictability for Spanish keywords was measured in a similar way to Phase two consisted of eight new paid participants, all intermediate level learners of Spanish at Northwestern University. Participants in this phase were presented with 100 sentences in which the final word was highly predictable from the context that preceded it, but this time with vocabulary that was reflected in Phase One’s results. Results contained 67 sentences with at least 88% (7 out of 8 participants) agreement on final word response, indicating that the context from early words in the sentence strongly predicted the final keyword.the or a) were given in Spanish to participants so as to eliminate any influence of grammatical gender on predictability. For example, in Spanish the word “the” can be written as either el or la, indicating that the morphological gender of the noun that follows is either masculine or feminine, respectively. To eliminate any artificial effects of gender influencing predictability, these 12 participants saw sentences with el/la (or la/el) before each final word when necessary. The ordering of these articles was randomized across all 70 sentences.In phase 3, the top 70 sentences (67 sentence frames with at least 88% agreement and 3 with at least 75% agreement) were selected for additional testing on 12 new intermediate level Spanish learners at Northwestern University. However, during this phase, both grammatical gender forms of the article . Additionally, the stimuli contained no cognates across languages in order to avoid any confounds based on lexical similarity across languages. We selected the best 60 sentence frames for the current study’s stimuli. No sentences contained the same keyword across languages . A rating of 1 indicated “I am unfamiliar with this word and I do not know how to use it in Spanish”. A rating of 4 indicated “I recognize this as a Spanish word, but I am unsure of its meaning”. A rating of 7 indicated “I recognize this as a Spanish word and I know how to use it”. Participants were asked to provide a rating from 1–7 and provide an English translation if possible. The median rating for all content words used in the study was 6.92 (out of 7) with a standard deviation of 0.49, indicating that participants were highly familiar with all content words in the final stimuli and that vocabulary level was unlikely to influence agreement of the final keywords. Two additional L1 Spanish speakers checked all of the final 60 stimuli for grammar and spelling errors.2.2.3.Stimuli were recorded in a sound-attenuated booth using a Shure SM81 Condenser Handheld microphone. The talker for the stimuli was a simultaneous Spanish-English bilingual for whom the age of acquisition of both languages was approximately 0 (at birth). Sentences were displayed on a computer monitor one at a time with breaks every 20 sentences to avoid fatigue and disfluencies. Speech style and language were blocked such that Spanish was recorded first, followed by English. Clear speech always preceded plain speech styles to avoid any second-mention reduction effects e.g.,  in the c2.2.4.Three L1 Spanish and three L1 English speakers were asked to rate the stimuli recorded by this simultaneous bilingual talker. 20 sentences were randomly selected from each language and given to raters who were instructed to rate her accent on a scale from 1 to 7. 1 indicated “this talker has an L2 accent/is a highly accented speaker of the language” and 7 indicated, “this talker has an L1 accent/is an unaccented speaker of the language”. The average rating for English was 6.75/7 and for Spanish 6.3/7, indicating that this talker is a highly proficient, unaccented speaker of both English and Spanish.2.3.The experiment took place over two days to avoid confounds of language mixing. Day 1 was entirely in English and Day 2 was entirely in Spanish. Because the heritage speakers (the group of interest) were English dominant, we expected that the Spanish session would be the more difficult experimental session. Therefore, SHS would benefit from the Spanish session coming second as they would be able to accommodate to the task, effectively making it harder for us to observe lower cores in Spanish. Any lower abilities to recognize Spanish than English speech-in-noise would then not be able to be accounted for solely on the basis of a lack of task adaptation.The study is a fully crossed design with three factors at two levels (enhancement/high or degradation/low) each. As discussed above, the three factors included signal-to-noise ratio (SNR), semantic predictability, and speech style. SNR was set at +5 dB (enhancement/high) and 0 dB (degradation/low) for both languages. The noise used in the study was speech-shaped noise leveled at the respective SNRs  by leveling all sentences to the same baseline and then manipulating the level of the speech-shaped noise to generate both +5 and 0 dB SNR differences. To reduce perceptual difficulties due to the onset of noise and speech occurring at the same time, each sentence was surrounded by a 500 ms noise lead or lag at the start or end of the stimulus, respectively. Semantic predictability consisted of 60 highly predictable frames (enhancement/high) in English and Spanish and 60 frames in English and Spanish that did not contribute to the context of the sentence (degradation/low). Speech style was either clear speech (enhancement/high) or plain speech (degradation/low).Stimuli were blocked by SNR with the easier +5 dB SNR coming first for both languages. This ensured that any observed reduction in final word recognition accuracy in the harder SNR (0 dB) would have exceeded any benefit gained from a task practice effect. Speech style (clear versus plain) and predictability (high versus low) were randomized within each block of SNR to avoid task learning confounds. If speech style were blocked, participants could be more likely to pay less attention to the content of the sentence during the clear speech block, since they would have realized that the final word was always going to be produced in a clear speaking style. Additionally, the low predictability sentence frames often repeat elements such as “Mom read about the … ” or “Dad thought about the … ”. By completely randomizing predictability, participants had less opportunity to learn that a particular group of keywords would not be identifiable based on context and thus, they were forced to listen to the entire sentence each time.The same participant heard each keyword only twice: once in a high predictable context and once in a low predictable context within the same SNR block. SNR and speech style were held fixed for each keyword by participant. For example, a given keyword might be presented at +5 dB SNR and in clear speech in both the high and low predictability contexts. Thus, the effect of predictability could be assessed as a within-participant factor with SNR and style fixed.Using MaxMSP software for stimulus presentation, participants listened to each sentence one at a time over Sony MDRV700 headphones in a sound attenuated booth. Participants were instructed to type in the last word of every sentence and that they could guess or type, “I don’t know” if they were unsure of the final word.In order to score the outputs, participants’ responses were matched with the actual keyword. Correct identification of the final keyword received a score of 1, while an incorrect score received a score of 0. Spelling errors were ignored, specifically in cases where incorrect spelling did not contribute to a difference in meaning . That is, if a participant misspelled or mis-inflected  a word in a way that indicated accurate auditory recognition, the word was still counted as correct receiving a score of 1. Incorrect number markings  were considered incorrect in both languages. In the case of multiple inflectional errors such as gender and number in Spanish, the word was then considered incorrect receiving a score of 0.3.The main goal of this study is to examine differences in L1 and L2 speech processing between two types of bilinguals: L2 learners (L1-dominant) and heritage speakers . As such, we built two separate logistic mixed effects models comparing the SHS group to each of the two L1-dominant learner groups: (1) SHS versus L1-English/Spanish learners (L1-E/SL), and (2) SHS versus L1-Spanish/English learners (L1-S/EL). The structures for these two models were identical. Both models included each of the three enhancement factors ) as fixed factors. The interactions between all factors  were also included. All factors were contrast coded to their respective enhancement/high and degradation/low values. Language of the task (English versus Spanish) and listener group  were also contrast coded within each model to compare the effects of each language on the three listener groups. As the interactions between language, listener group, and each signal manipulation are the critical comparisons for this study, these three three-way interactions were also included in both models for assessment . The maximal random effects structure that converged was utilized for both models. The final two models included random intercepts for participant and keyword, and random slopes included all main effects (except listener group) and a language-factor interaction for each signal manipulation by subject and predictability by keyword. The significance of each factor (and interaction) was then determined within each model using the model comparison method, which relies on chi-squared values to determine whether the presence of a single (n − 1) factor (or interaction) significantly improves the fit of the data. The results of both models, which separately compare SHS to each of the two L1-dominant/learner groups, will be presented together, grouped by each enhancement factor .3.1.2(1) = 24.57, p < 0.05), indicating that words produced in clear speech were more likely to be correctly recognized than those produced in plain speech. The interaction between style and language was also significant  = 14.01, p < 0.05), which suggests both L1-E/SL and SHS benefitted more from English clear speech than Spanish clear speech. This result is consistent with 2(1) = 4.52, p < 0.05) such that SHS showed less of an overall benefit in clear speech compared to L1-E/SL. However, the three-way interaction between listener group (L1-E/SL versus SHS), language, and style was not significant  = 1.7, p > 0.05), suggesting that neither of these two-way interactions were influenced by the remaining factor.With respect to L1-E/SL versus SHS, there was a significant main effect of speech style  = 23.43, p < 0.05), indicating that keywords produced with clear speech were more accurately recognized than keywords produced with plain speech. The three-way interaction between style, language, and listener group was significant  = 6.33, p < 0.05), suggesting that SHS and L1-S/EL did not equally benefit from speech style across both languages. That is, SHS failed to benefit from clear speech in Spanish, whereas L1-S/EL benefitted from clear speech in both languages. Additionally, there was a significant interaction between style and listener group  = 7.89, p < 0.05), which, like above, suggests that SHS showed an overall smaller benefit from clear speech. The interaction between style and language was also significant  = 12.45, p < 0.05) such that the overall benefit for clear speech was greater in English than in Spanish. While this result may be inconsistent with With respect to L1-S/EL versus SHS, there was a significant main effect of speech style  = 4.19, p < 0.05), indicating that highly semantically predictable contexts aided the recognition of final keywords. The interaction between listener group and predictability was significant  = 8.01, p < 0.05), such that SHS benefitted more from semantic predictability than L1-E/SL. Although the interaction between predictability and language was not significant  = 1.19, p > 0.05), the three-way interaction between listener group (L1-E/SL versus SHS), language, and predictability was significant  = 9.51, p < 0.05). This suggests that SHS and L1-E/SL did not equally benefit from predictability across both languages. While the two groups showed similar benefits from predictability in English, SHS showed a much stronger predictability benefit in Spanish than L1-E/SL. Consistent with 2(1) = 32.79, p < 0.05), indicating that listeners were aided more by clear speech in high predictability contexts.With respect to L1-E/SL versus SHS, there was a significant main effect of predictability  = 14.53, p < 0.05) such that keywords were more accurately recognized when there was ample supporting context in the sentence that preceded them. While both the interaction between listener group and predictability  = 1.13, p > 0.05) and language and predictability  = 1.11, p > 0.05) were not significant, there was a significant three-way interaction between predictability, language, and listener group  = 9.18, p < 0.05), suggesting that SHS and L1-S/EL did not equally benefit from predictability across both languages. That is, although both SHS and L1-S/EL benefitted from predictability in Spanish, SHS showed a much stronger predictability benefit in English compared to L1-S/EL. Again, consistent with Bradlow and Alexander, the interaction between style and predictability was significant  = 41.62, p < 0.05) such that clear speech more greatly aided word recognition in highly predictable contexts than in low predictability contexts.With respect to L1-S/EL versus SHS, there was a significant main effect of predictability  = 52.7, p < 0.05), suggesting that final keyword recognition was improved in the favorable SNR condition, +5 dB. The interaction between SNR and language was significant  = 6.59, p < 0.05), indicating that both L1-E/SL and SHS were more resistant to noise in English than Spanish. The interaction between listener group and SNR was not significant  = 0.47, p > 0.05), nor was the three-way interaction between SNR, listener group (L1-E/SL versus SHS), language  = 0.049, p > 0.05), indicating that L1-E/SL and SHS were comparably affected by SNR manipulations in both languages. Both the interaction between style and SNR  = 0.01, p > 0.05) and the interaction between predictability and SNR  = 0.99, p > 0.05) were not significant.With respect to L1-E/SL versus SHS, there was a significant main effect of SNR  = 52.8, p < 0.05) as final keyword recognition improved at the easier SNR (+5 dB). The three-way interaction between SNR, language, and listener group was significant  = 4.35, p < 0.05), suggesting that SHS and L1-S/EL were differentially affected by noise across both languages. While the interaction between listener group and SNR was not significant  = 0.01, p > 0.05), there was a significant interaction between language and SNR  = 6.46, p < 0.05). Taken together, these results suggest that overall while SHS and L1-S/EL were similarly affected by noise, SHS were more resistant to the presence of noise in English compared to L1-S/EL. Furthermore, the interaction between style and SNR was not significant  = 0.21, p > 0.05). However, the interaction between predictability and SNR was significant  = 8.05, p < 0.05), indicating that highly predictable contexts aided keyword recognition in higher levels of noise.With respect to L1-S/EL versus SHS, there was a significant main effect of signal-to-noise ratio (SNR)  and/or the amount  of linguistic exposure affected speech learning outcomes in adults. Due to the de-confounding of these aspects of the language learning context—early versus extended language exposure—in switched-dominance bilinguals , we were able to investigate their independent influences on speech recognition accuracy under various enhancement/degradation conditions. Specifically, we compared recognition accuracy of sentence-final words in spoken sentences embedded in background noise by L2-dominant Spanish Heritage Speakers  as compared to L1-dominant bilinguals in both languages. In the current study, we manipulated three factors that are known to either enhance or degrade recognition of sentence-final keywords: contextual predictability , signal-One hypothesis is that if early exposure is critical for complete L1-like performance in a language , heritagAn alternative hypothesis emphasizes the critical role of language dominance affecting language processing , predictWith respect to non-dominant L2 learners (L1-English/Spanish learners (L1-E/SL) and L1-Spanish/English learners (L1-S/EL) in this study), these hypotheses do not make opposing predictions since the L2 for these bilinguals is both late-acquired and non-dominant. If early AoA  and langWhy did the SHS fail to benefit from clear speech in Spanish despite benefitting in both Spanish and English from each of the other two enhancements tested in this study (SNR and predictability)? One possible explanation for why SHS did not receive a Spanish clear speech benefit is that the simultaneous Spanish-English bilingual used for stimuli recording did not produce a strong clear speech effect in Spanish. However, if this were true, then we would expect to see no benefit for L1-E/SL or L1-S/EL in Spanish clear speech. This is not the case see ; in fact5.The current study found that Spanish Heritage Speakers (SHS) who are dominant in their L2, English, demonstrated speech-in-noise recognition accuracy at similar levels to L1-dominant English listeners. However, speech recognition vulnerabilities related to signal degradation emerged for these SHS in their non-dominant L1, Spanish. Combined with generally better SHS than late L2 Spanish learner recognition accuracy of Spanish, these results suggest that while early exposure can afford substantial speech processing benefits, extended exposure and usage are necessary for robust L1-like speech-in-noise recognition. While the data from this study revealed subtle differences in non-dominant language speech recognition compared to their dominant language, it is critical to acknowledge that the bilingual language learning experience of switched dominance/heritage speakers affords obvious life-long benefits in terms of total language proficiency. In the present study, the sum of the English and Spanish cloze test scores for all three listener groups showed that the total language proficiencies of the Spanish Heritage Speakers exceeded that of both the L1-English/Spanish learners and the L1-Spanish/English learners, emphasizing the remarkable language asset of the heritage language learner experience.