This report summarizes recent advances of flexible humidity sensors and their integrated systems.Typical examples of noncontact detections based on flexible and wearable humidity sensors are highlighted.Research opportunities and challenges of pushing flexible humidity sensors towards practical contactless measurements are discussed. In the past decade, the global industry and research attentions on intelligent skin-like electronics have boosted their applications in diverse fields including human healthcare, Internet of Things, human–machine interfaces, artificial intelligence and soft robotics. Among them, flexible humidity sensors play a vital role in noncontact measurements relying on the unique property of rapid response to humidity change. This work presents an overview of recent advances in flexible humidity sensors using various active functional materials for contactless monitoring. Four categories of humidity sensors are highlighted based on resistive, capacitive, impedance-type and voltage-type working mechanisms. Furthermore, typical strategies including chemical doping, structural design and Joule heating are introduced to enhance the performance of humidity sensors. Drawing on the noncontact perception capability, human/plant healthcare management, human–machine interactions as well as integrated humidity sensor-based feedback systems are presented. The burgeoning innovations in this research field will benefit human society, especially during the COVID-19 epidemic, where cross-infection should be averted and contactless sensation is highly desired. Skin-like electronics that imitate the multifunctional properties of human skin are emerging as rising stars for potential applications in healthcare monitoring, human–machine interfaces, implantable bioelectronics and intelligent robots –7. OwingBased on a proton-hopping mechanism, a variety of active materials have been investigated for humidity sensors. These functional materials are typically endowed with superior affinity to water molecules and highly exposed surface areas so as to achieve high-performance flexible humidity sensors with high sensitivity, fast response, low hysteresis as well as superior stability –41. HoweBy means of high-performance flexible humidity sensors, they have been applied in noncontact detections owing to their capability to perceive moisture variations , 49, 50.In this report, we present a timely overview of multifunctional skin-like humidity sensors from the basic materials and working principles to noncontact applications Fig. . First, 2O + H3O+  = H3O+  + H2O . A. A74]. A2 nanostructures  and reduced graphene oxide (rGO)) have been extensively investigated as humidity or gas sensors owing to their large surface area, low toxicity, mechanical compliance and good chemical stability 97]. Prim2, VS2, WS2, ZnIn2S4, CdS etc. . . − and Ce months . The adse months . 3.2.2. π electrons on the double bond can migrate to form a current. Typical intrinsic conductive polymers refer to polyaniline (PANI), polypyrrole (PPy) and polythiophene (PEDOT) etc. [TFSI]) and 1-butyl-3-methylimidazolium tetrachloroferrate ([Bmim][FeCl4]) [4] was developed for humidity sensing applications  –145. As [FeCl4]) . Moreoveons Fig. d. Upon ions Fig. e. As a rons Fig. f 143]. . 2) and ons Fig. g. Notablons Fig. h 147]. . 2) and To apply the flexible humidity sensors for noncontact measurement, highly sensitive and perdurable devices are desired. However, their performances are still insufficient for practical applications primarily due to relatively low sensitivity, narrow detection range, apparent hysteresis and poor cyclic stability , 46. Mea+ ions at defect sites to improve the humidity sensitivity via surface doping of nitrogen atoms on mesoporous TiO2 structures [5 from dry to 90% RH conditions. It is worth noting that the adsorbed oxygen molecules on surface defect sites significantly improve the affinity of sensing materials with water molecules, thereby enhancing the humidity sensitivity.To overcome the low sensitivity of humidity sensors, chemical doping is one of the reliable methods via increasing the hydrophilic sites on active nanomaterials. The common dopants comprise metals , 148, io3-based humidity sensor with rich structural defects [+ ions, water molecules are polarized to promote the generation of H+/H3O+. Meanwhile, the doped K+ ions serve as mobile carriers to improve the conductivity. The Li/K-codoped device provides a large number of structural defects and enhances the adsorption of oxygen, which contributes to adsorbing water molecules and then boosting humidity-sensitive performance  template method, through which a highly uniform pore-structured nanomaterial was successfully obtained  of an adult  is achieved when exposing the device in moisture due to ion concentration gradient generated on GO. The self-powered humidity sensor can distinguish the finger position via observing the ON/OFF of LEDs. The sensor can be also attached onto a robot arm as an artificial skin for safe human–robot interactions  were hybridized for humidity sensors based on TENG. A steady output voltage up to 24 V is achieved with a wide sensing range from 0 to 97% RH [Most of such noncontact applications require continuous power supplies, which may restrict the long-term use in Internet of Things with a large quantity of sensor networks. The chemicals in batteries may also cause environmental issues. Thus, self-powered flexible sensors without external powers are highly appreciated for practical applications. As discussed in Sect. ons Fig. h-i. Anoto 97% RH . Furthero 97% RH . A relatWith the remarkable improvement of humidity sensing performance, flexible humidity sensors have not only demonstrated their merits in human healthcare monitoring, but also exhibited significance in dynamically tracking plant health status to ameliorate the productivity , 175–177th day present reduced width of stomata, compared to that in the first day, indicating the drought condition of this plant. However, after resupplying the water, the capacitance of GO-based humidity sensor increases to the original value. This implies that this plant already recovers to the energetic status  and excellent flexibility of this device, it could be conformally attached onto the leaf surface  due to tough desorption of water molecules from the device. This drawback limits their perdurable applications, although porous structures or Joule heating can sustain the performance to some extent. An effective strategy relies on the strong reducibility of hydrogen atoms on the Pd surface to regulate hydroniums, which achieves a highly stable humidity sensor for over 100 h (90% RH) almost without performance degradation . Further


The absorption sensor achieves the absorption efficiency of 99.41% and 99.22% at 5.664 THz and 8.062 THz, with the absorption bandwidths 0.0171 THz and 0.0152 THz, respectively. Compared with noble metal absorbers, our graphene absorber can achieve tunability by adjusting the Fermi level and relaxation time of the graphene layer with the geometry of the absorber unchanged, which greatly saves the manufacturing cost. The results show that the sensor has the properties of polarization-independence and large-angle insensitivity due to the symmetric structure. In addition, the practical application of testing the content of hemoglobin biomolecules was conducted, the frequency of first resonance mode shows a shift of 0.017 THz, and the second resonance mode has a shift of 0.016 THz, demonstrating the good frequency sensitivity of our sensor. The S (sensitivities) of the sensor were calculated at 875 GHz/RIU and 775 GHz/RIU, and quality factors FOM  are 26.51 and 18.90, respectively; and the minimum limit of detection is 0.04. By comparing with previous similar sensors, our sensor has better sensing performance, which can be applied to photon detection in the terahertz band, biochemical sensing, and other fields.The paper proposes an ultra-narrow band graphene refractive index sensor, consisting of a patterned graphene layer on the top, a dielectric layer of SiO Surface plasmons (SPs) are two-dimensional plane waves propagating along the interface between metal and dielectric, which can confine subwavelength of the electric field in the direction perpendicular to the dielectric for the purpose of controlling light ,2. SurfaElectromagnetic metamaterial is a new type of artificially designed composite material with a structural size smaller than the wavelength of external incidence, which has peculiar optical properties such as a negative refractive index and a negative magnetic permeability. In addition, the desired metamaterial properties can be achieved by designing subwavelength structures ,15. CurrBased on the advantages of the above properties of graphene materials, it is possible to achieve optimization of sensor performance. In real life, optical sensors of graphene-based SPR can be used for bio-detection such as single cells, antigen antibodies, proteins and so on ,28,29. ITerahertz waves lie between 0.1 and 10 THz, and are mainly excited by intramolecular and intermolecular vibrations ,35. Alth2 in the middle, and a bottom metal layer, as shown in 2 has a relative permittivity of dε = 1.4 and a thickness of st = 28 µm. The structural period of the basic cell is P = x = PyP = 15 µm. The bottom metal layer adopts lossy Au with conductivity σ = 4.09 × 107 S/m and the ply ta = 0.5 µm, which can block the transmission of terahertz waves efficiently [1r and 2r of the top patterned graphene are 1 µm and 3.5 µm, respectively, and the outer ring radii 3r and 4r are 5 µm and 7 µm, respectively. Based on this structure, the simulation was conducted by using FDTD (Finite difference time domain) solutions software [x- and y-directions, periodic boundary conditions are used. In the z- direction, perfect matching layer (PML) 24 layers is applied. The simulation temperature in our work is set to 300 K. In the simulations of this paper, the thickness of the monolayer graphene is set to 1 nm. By modulating the material parameters of the graphene layer, it was found that the optimal absorption efficiency of this absorber in the terahertz band was achieved when FE = 0.7 eV and τ = 0.7 Ps.Our proposed ultra-narrowband absorber structure consists of a patterned graphene layer on the top, a dielectric layer of SiOiciently ,44. The software . During g = σintra + σinter, with σintra represents intra-band conductivity, σinter is inter-band conductivity. According to Kubo formula, the conductivity of graphene can be described by [e = 1.6 × 10−19 C, BK refers to the Boltzmann constant, ħ represents the approximate Planck constant, T, ω refers to the ambient temperature and angular frequency of the incident wave, respectively. EF and τ refer to the Fermi level and relaxation time of the graphene layer, respectively. The σinter of graphene is negligible since EF >> ħω in the terahertz band, and the surface conductivity of graphene depends mainly on intra-band contribution. Therefore, the total conductivity of graphene can be simplified as Drude formula [The total conductivity of graphene we used can be obtained from σribed by ,47:(1)σi formula :(3)σ(ω)=From the above equation, it is clear that the graphene optoelectronic devices can achieve active adjustability by means of regulating the Fermi level and relaxation time. The property simplifies the design of optoelectronic devices and increases the flexibility in different cases.0/Δf [As displayed in 0/Δf , are 171wB is used, which is expressed as the ratio of total bandwidth to center frequency, and defined as [maxf and minf are the highest and lowest frequencies, respectively. If wB is less than 1%, it is considered narrowband. If wB is in the range of 1~25%, it is considered wideband, and if wB is greater than 25%, it is considered ultra-wide band. In our work, the absorption bandwidths of the two resonant frequencies where the absorption efficiency remains above 80% are 0.0171 (5.6552~5.6723 THz) and 0.0152 (8.0551~8.0703 THz), respectively. Therefore, according to equation (4), the relative absorption bandwidths wB at the two resonant frequencies were calculated to be 0.0301% and 0.0188%, respectively. wB is much less than 1%, so the absorber is ultra-narrow band absorption. The total absorption bandwidths are 0.033 THz and 0.041 THz, respectively.To calibrate the bandwidth level of the absorber, the parameter relative absorption bandwidth fined as :(4)Bw=2×x-y plane first, then observed and plotted the cross-sectional electric field distribution diagram, as demonstrated in To investigate the intrinsic mechanism of perfect absorption of the absorber, we set separate frequency-domain field monitors at 5.664 THz and 8.062 THz respectively in Z can be calculated by the Equation (5) [The impedance matching principle is a significant theoretical basis to achieve perfect absorption of the absorber. The equivalent impedance tion (5) :(5)Z=) of the effective impedance Z of the system had a value close to 1, and the imaginary part (Im(Z)) was close to 0, so the reflection (S11 = 0) could be greatly decreased, for which a perfect absorption was acquired. According to Z deviated from 1 and 0, respectively, the absorption efficiency decreased sharply. It proved that the proposed graphene SPR ultra-narrow perfect absorption was due to the impedance matching at the frequencies of 5.664 THz and 8.062 THz.Here, FE is as follows [gV, e0, FV and st is external voltage, electron charge, Fermi velocity and the ply of SiO2 layer, respectively. Among them, gV can be modulated by adjusting the external voltage or chemical doping. Besides, ε0 and rε denotes the vacuum permittivity and relative permittivity, respectively. FE = 0.7 eV.Based on the tunability of graphene materials, the changes of absorption spectra of the absorbers were next investigated by regulating the Fermi level and relaxation time of the graphene layers, respectively, as shown in  follows ,53:(6)EFτ of the patterned graphene layer was calculated by [FE, ν is the Fermi level, carrier mobility of graphene, respectively. e is the electronic charge, and FV = 106 m/s. The absorption spectra of the absorber illustrated in τ increased from 0.7 Ps to 5 Ps. The results showed that the absorption efficiency changed gradually and the resonance frequency remained unchanged. Another interesting phenomenon that appears in τ, and the strong plasmonic oscillations will interact with the surrounding medium, resulting in fluctuations around the two absorption peaks. The modulation ranges of the absorption efficiency were 87.83% to 99.41% and 95.45% to 99.22%, and the modulation depths were 11.58% and 3.77%, respectively. Therefore, graphene absorbers could achieve the tunability of the absorption spectrum by regulating the Fermi level and relaxation time of the graphene layer with the geometry of absorber unchanged, which had a higher value than conventional metal absorbers in more actual fields.The electron relaxation time lated by :(7)τ=EFvz- axis, when the electric field only had a horizontal component in the x-y plane, it was called TE waves. When the magnetic field only had a horizontal component in the x-y plane, it was called TM waves [In real life, vertical incidence plane wave was just one of these cases. The real situation was more complicated and volatile. Therefore, the studies on the insensitivity to oblique incidence of absorber were necessary ,55,56,57TM waves . Figure n increased, which, indicating the resonance modes, were sensitive to the refractive index. We then measured the sensor capability quantitatively by calculating the parameters of S (Sensitivity) and FOM . According to the sensitivity Formula (8) [f and ∆n are the changes in resonance frequency and ambient refractive index, respectively. P of the two resonance modes were 0.04, 0.05, respectively. The smaller detection factor exhibited a higher refractive index sensitivity and better sensing characteristics of our sensor. After comparing with the works of those who came before us, our absorption sensor had the advantages of dual-band absorption, dynamic tunability, high refractive index sensitivity, and good sensing performance, as shown in The sensor capability is explored in mula (8) ,60:(8)S=o FWHM/S . And accFinally, we investigated the sensing performance of our absorption sensor applied in real time. wB at the two resonant frequencies were calculated to be 0.0301% and 0.0188%, and the Q-factors were 171.64 and 196.63, respectively. Associating with the dynamic tunability of graphene, the resonant frequency bands can be modulated efficiently by adjusting the Fermi level and relaxation time of the top graphene. The polarization-independence and wide-angle insensitivity characteristics of the absorber were studied by changing the polarization mode and incidence angle of the incident light. Finally, the sensing characteristics of the absorption sensor were investigated. The calculated sensitivities of the sensor were 875 GHz/RIU and 775 GHz/RIU, quality factors FOM  were 26.51 and 18.90, and the minimum limit of detection was 0.04. In addition, the practical application of testing the content of hemoglobin biomolecules was conducted, and the results show that our sensor had good sensing performance, which can be expected to be applied in optical detection, medical imaging, biosensing, and other fields.In this paper, ultra-narrow perfect absorbers in the 5–9 THz band were obtained based on the single-layer graphene SPR structure. By designing the structure, perfect absorption was obtained at 5.664 THz and 8.062 THz with absorption efficiencies of 99.41% and 99.22% and absorption bandwidths of 0.0171 THz and 0.0152 THz, respectively. The relative absorption bandwidths


The HIV burden remains a critical public health concern and adolescent girls are at significantly higher risk compared to the general adult population. Similar to other sub-Saharan African countries, Uganda reports high HIV prevalence among adolescent girls and young women. Yet, both evidence-based HIV prevention interventions and their acceptability among adolescent girls have not been widely studied. In this study, we examined the acceptability of the Suubi4Her intervention, an evidence-based combination intervention aimed at reducing HIV risk among adolescent girls in Uganda.We conducted semi-structured in-depth interviews with 25 adolescent girls upon intervention completion to explore their experiences with the Suubi4Her intervention that was tested in a clinical trial in Uganda (2017–2023). Specifically, we explored their decision-making process for participating in the intervention, experiences with program attendance, and their feedback on specific intervention characteristics. Informed by the Theoretical Framework of Acceptability, the data were analyzed using thematic analysis.The main motivation for participation was access to health-related information, including information on STIs, HIV, and pregnancy as well as information on banking, saving, and income-generating activities. Though many participants did not have any initial concerns, mistrust of programs, initial paperwork, caregiver’s ability to commit time, concerns about ability to save, and HIV/STI and pregnancy testing were raised by some participants. Facilitators to session attendance included motivation to learn information, caregiver commitment, reminder calls, and incentives received for participation. The main challenges included household responsibilities and obligations, difficulty raising transport money, and weather challenges. Adolescent girls appreciated the group format and found the location and times of the sessions convenient. They also found the content relevant to their needs and noted positive changes in their families.The results showed high intervention acceptability among adolescent girls. These findings have important programmatic and policy implications in Uganda, especially given the higher HIV prevalence among adolescent girls in the country.NCT03307226 (Registered: 10/11/17). Sub-Saharan Africa (SSA) continues to be heavily impacted by the HIV epidemic, with 67% of the people living with HIV residing in the region . In addiIn many SSA countries, including Uganda, household financial stability is strongly associated with access to education, a protective factor , especiaWhile there are studies testing the effectiveness of interventions targeting youth mental health or HIV prevention in low and middle-income countries (LMICs), intervention acceptability studies among adolescents in LMICs, and specifically in Africa, are still limited . This isWhile this review provides important insights into factors that increase intervention acceptability, all interventions were either single interventions or only explored the acceptability of one component of a combination intervention, leaving out the opportunity to assess the acceptability of an intervention as a package. Other acceptability studies, in the context of HIV prevention in particular, primarily focus on pre-exposure prophylaxis (PrEP) uptake in the form of facilitators and barriers –33. HencAgainst this backdrop, in this study, we explore the acceptability of a combination intervention named Suubi4Her  that tested the impact of Suubi4Her on reducing HIV risk among adolescent girls in Uganda.Suubi4Her, combined savings-led economic empowerment through youth development accounts (YDA) and evidence-based family strengthening intervention delivered via multiple family groups (MFG). The three study conditions are: 1) Control condition: bolstered usual care that involves standard health and sex education, provision of textbooks, notebooks, and pens; 2) Treatment condition 1: YDA, Financial Literacy Training (FLT) and Income-generating Activities (IGA); and 3) Treatment condition 2: YDA-FLT-IGA + MFG. The study enrolled 1260 school-going adolescent girls (14 to 17 years of age) across 47 secondary schools located in five geopolitical districts, Rakai, Kyotera, Masaka, Lwengo, and Kalungu within the greater Masaka region.The Suubi4Her study, a five-year National Institute of Mental Health (NIMH) funded study, is a 3-arm cluster randomized clinical trial (2017–2023) that evaluates the impact of a combination intervention on reducing HIV risk among high school adolescent girls in Uganda. The intervention, titled Adolescents were eligible to participate if they met the following inclusion criteria: 1) female; 2) aged 14–17 years; 3) enrolled in the first or second year of secondary school; and 4) living within a family (broadly defined) and not an institution or orphanage, as those in institutions have different familial needs  participants’ experiences with the intervention in each treatment condition , including individual, family, and contextual factors that may have hindered and/or facilitated youth’s experiences in each treatment arm  and perceptions on program sustainability; and b) key multi-level factors  that may have impacted participants’ observable behaviors and decision-making in regard to savings, mental health, and sexual risk taking. In this study, we examine adolescent girls’ experiences with the Suubi4Her combination intervention (YDA-FLT-IGA + MFG).Uganda is one of the SSA countries hardest hit with HIV with unprecedented numbers of ALHIV  . AccordiIn addition to the sexual health education provided in all secondary schools in Uganda, adolescent girls in this study arm received a family economic empowerment intervention that included incentivized YDA held in the adolescent's name together with their caregiver in a financial institution. The savings in the YDA were matched by the program with a ratio of 1:1. They were allowed to invest up to 30% of their total matched savings in a family-based income-generating business. The remaining 70% of the savings were to be used to support the education and skill development of adolescent girls. Participants’ access to the matching funds was contingent upon them completing the 4-session manualized FLT sessions offered together with YDA .FLT sessions were delivered by trained facilitators. Each session , animal husbandry , tailoring, weaving baskets, and knitting. Participants also received information on how to market their products resulting from IGAs and manage a small kiosk. Finally, participants were linked to a local marketing agency that bought their finished products.The MFG family strengthening intervention, called Amaka Amasanyufu , is an evidence based 16-session manualized intervention delivered by trained parent peers and community health workers. The intervention is organized around six constructs: four Rs  and two Ss  that target parenting skills and family processes. The intervention aims at building support for families through opportunities for caregivers and children to communicate in a safe setting with other families who have similar experiences, thus allowing families to benefit from each other’s contributions . The manThe multiple family groups involved 15 to 20 families, with the adolescent participant and at least one adult caregiver to the target participant present in each session . Lasting approximately one hour, sessions included group discussions, role-plays, and other activities that foster support, learning, and interaction both within and among the families participating in the sessions. The sessions were delivered bi-monthly in schools on days when classes were not in session . Sessions were facilitated by two facilitators, specifically community health workers and peer parents already trained in MFG intervention as part of the NIMH-funded SMART Africa study .n = 381 adolescent girls). Specifically, we used biomarker (STI and HIV) data to stratify participants who screened positive (new cases) and negative at 12-month follow-up for sexual risk-taking.. We stratified participants in the lowest and highest quartiles in mental health using theBeck’s Depression Inventory scale , you can send [deposit] it and keep it in your account and then use it in the future, to help you in your education, to buy necessities and others.“our parents cannot teach us”, Annah was interested in the matched savings and income generating activities to be offered. She pointed out that in addition to the matched savings being helpful for school fees, opportunities to learn about the importance of saving and how to start small business informed her decision to join.In addition to being excited to learn knowledge that Annah: The other thing is you get to know that not every money you get, you to have to eat [spend it] it. That is not a good thing. You can start a small business and when you get money after selling something from the business you can buy yourself something like clothes and topping up on school fees together with your parents.“learning new things concerning the girl child”. Similarly, Flora expected that the program would improve her relationship with her parents. Joseline also was motivated by the opportunity to learn about “a happy family, the way we can relate to friends and neighbors”.Though discussed less frequently, some participants identified the focus on family relations as a motivation. For instance, Sarah mentioned sharing about her family relations in addition knowing her HIV status and Adolescent girls talked about what made them hesitate to participate when they first heard about the Suubi4Her program. More than half of them mentioned that they had no concerns. However, while one of the participants did not have any concern about participation, she noted the challenges of putting together the documents needed for account opening such as birth certificates and passport size photos. She worried that this might prevent her from joining the program but was able to get all the documents with help from her father.Racheal: I wasn’t sure I would get them [the required documents] or not. I prayed to God to enable me to enroll into the organization…. My dad took me to a distant place to obtain passport size photos and I also got the birth certificate.This was echoed by Margret who lived with her grandmother and her birth certificate was with her mother who lived far away. However, she had an immunization card with her birth date that she was able to use instead. She also added that she was hesitant about joining initially because she heard of programs that did things differently than what they originally presented.Margret: I heard that there are certain organizations that come to school and bring something like this with an aim which is very different. Just like they talk about this and this in the office yet their aims are very different and after registering students they do different things.“cheat” that would not deliver on what it promised and instilled doubt in her mind.Anisha shared a similar concern where her parents thought that the Suubi4Her program might be a Anisha: Because my parents said “we might take that child into that program where they are claiming they will open for her an account and yet they are cheats.” Since older people have had more life experiences, you also start to think these people might be cheats considering they are the ones who give us our bank account numbers, and if you want to withdraw you have to reach them first. This made me hesitate a bit.“this was a fake program”. Two participants, Ruth and Mariam, had initial concerns about their caregivers. Ruth was worried that her parents would not have the time to attend the program sessions because of their busy schedule. This was critical because the program was a family-level intervention that required caregiver attendance together with their child. She later was able to convince her caregiver to attend the sessions.However, she was convinced by her older sister’s determination to participate as well as the program staff’s reassurance that her savings would not be stolen, but rather matched. Violet also mentioned that some of the students at her school thought Ruth: What made me hesitant was when they told us to invite our guardians. Many parents do not have time to go to school, especially on project-related issues, which they don’t even know about. It was a challenging situation for us because some of our parents spend time at work and they think coming to school is just disrupting them.Two participants had concerns about whether they would be able to deposit or save during the program. Harriet shared that her father had another child in college that he was paying fees and expenses for. Hence, she was worried that there might not be enough money left for her to save in her account.Harriet: What made me hesitate was that part of saving. Okay, money wouldn’t be a problem but my father has another child who is a university student who was taking millions, so telling him about that saving stuff was going to be difficult.Finally, two participants were concerned about the testing for STIs, HIV, and pregnancy, though for different reasons. For Gloria, the concern was about potentially finding out about a positive pregnancy test and the shame associated with it.Gloria: As girls, you may be afraid of your health status because you might have done something like having sex unintentionally, and in case you’re informed that you’re pregnant, you feel ashamed. That might have made me afraid.being pricked all the time”. When she consulted with a friend, her friend reassured her that the blood sample will not be withdrawn all the time and that the needle would be small, after which she said “let's go and enroll so we can know our status.Annet, on the other hand, was afraid of “What made it possible for me to come for the sessions was to learn how to save, spend money where necessary, for example buying food instead of a dress of my choice.” Annet noted that she wanted to learn about what she could do to generate profits with the little money she had.One of the main facilitators that enabled adolescent girls’ attendance to both FLT & IGA and MFG sessions was the desire to learn and gain new knowledge. When talking about FLT and IGA sessions, Harriet stated that she was motivated to attend the sessions because she was interested in learning about savings and ways to manage their expenditures, “Annet: What enabled me to attend the sessions was because I was interested in what I am doing. I wanted to give in some time to learn and to know the things I can start up, with a little amount of money and generate huge profits.After attending the first session where she learned about saving and budgeting, Ruth indicated that it motivated her to continue attending the rest of the sessions.Ruth: What made it easy for me to attend the sessions is that after I attended the first session, I enjoyed it because they were training us about saving and the bank stuff, including budgeting for your money. After that, I decided to start attending the training sessions and made sure I get everything they were telling us.“The other things that enabled me to attend these training sessions were to learn how to communicate with my guardian, how I can approach him, and indeed, these sessions improved our morals.” Margret stated that despite the temptation of staying home and sleeping on a Saturday morning, she chose to come to sessions because “there is a lot to learn from there.”Participants also mentioned the motivation to learn new things as a facilitator to attending MFG sessions. For example, Ruth was motivated to learn how to better communicate with her guardian, which motivated her to attend the MFG sessions: Another facilitator to session attendance was being reminded ahead of time via phone calls by the team. Harriet noted that they received calls from the team for both FLT&IGA and MFG sessions:Harriet: They used to first communicate that on this particular day we have financial literacy training and other sessions, let it be respectful communication sessions, and I could come well prepared to listen and learn from the sessions.Similarly, Janet talked about doing her chores the day before when she received the reminder call to make sure she made it on time to the sessions. She added that her father made sure to inform her when he was informed.Janet: They used to inform us earlier on and this enabled us to do whatever we had to do a day before, such that we reduce the workload for that day of the sessions and to reach on time…We used not to be occupied at home and whenever dad was informed, he used to inform us as well.He could remind me and would ask me to attend every time because they were training about interesting things.” Anisha talked about her caregiver’s readiness to attend the sessions, whenever they were contacted, “Whenever my caregiver would be called and asked to come with me, she would leave whatever she was doing and come to attend the sessions.”Other participants also talked about their parents’ commitment. For instance, Ruth’s caregiver encouraged her to attend the sessions: "Participants also acknowledged the incentives provided to them as a major facilitator to continue attending the sessions. Specifically, participants were provided with lunch, and they were given a transport refund for every session they attended. Many participants appreciated the transport refund as this made it easy for them to continue attending the sessions. For example, Sarah noted that it was easy to attend because lunch and transportation to the venue were provided. Indeed, Annah noted that the money motivated her to attend the session, as she would later use that money to buy chickens to generate income in the future.Annah: What enabled me to attend them, first of all, they would give us some money which I could use to buy chicks and rear at home. After some time, when God wills, they would lay eggs and produce other chicks which would also eventually grow. So even if you bought like two chicks, they would multiply then you sell and get some money…She went on to add that a “well-balanced diet lunch” provided during the sessions was another facilitator. Echoing similar thoughts, Rose mentioned that she did not have to worry about cooking since the training provided lunch for them,“What enabled us to participate in the Happy Family training is that; they were providing lunch, so we didn’t have to worry about cooking.”My aunt whom I live with was going somewhere and she could leave the child behind with no one so I had to stay at home.”Some adolescents reported not having any difficulties attending the sessions. Other participants identified several factors that made it a challenge to participate in training sessions. These included household responsibilities and obligations, difficulty raising transport money despite transport refunds, long distances, and weather challenges among others. For example, Ester found it hard to attend some of the sessions due to childcare responsibilities: ““We weren’t able; by the time she recovered, the sessions were about to end.”Agnes missed attending a session because they had lost a relative and her mother asked her to stay at home, so she could go to the burial. Olivia mentioned that she had difficulty attending the sessions because her mother was sick. When asked if she was able to overcome the challenge, Flora had to stay at home whenever her grandmother was away. Even after informing her grandmother of the sessions, she could not find someone else to stay home with the young children.Flora: Sometimes I had to stay at home with the children when my grandmother was away, so I would not attend…I would tell her that I will be going for training this date and she allows me, but she will not have someone to stay at home. “A parent wanted to dig in the morning and evening and whenever she would think of spending time in the sessions from 9 am to 4 pm, she would consider it a waste of time.”Gloria indicated that while she was interested in attending the sessions, her parent thought that they could be spending that time working in the garden instead,Relatedly, Anisha talked about the challenge of completing the session homework for the following session due to household responsibilities and felt worried to attend the next session.Anisha: We would be given take-home assignments during the sessions. However, sometimes I would be so busy at home and would fail to get time to do the assignment. So, I would sometimes be anxious to come for the next session without doing the assignment.We found challenges with the weather changes like on days when it had rained heavily. This could make us report late for the sessions. That was the only barrier.”Several participants were challenged by weather conditions, specifically the heavy rains during the intervention period. They talked about getting to the training venue late and missing out on the beginning of the sessions. For example, Rose noted that sometimes it would rain from early morning to mid-day, making it hard for her to get to the session venue on time. Janet shared “While participants were given transport refunds after each session, they had to raise the money to get to the venue. Fiona noted that in addition to the heavy rains, sometimes it was challenging to get money for her to get to the venue.Fiona: Sometimes it could rain heavily and also sometimes we were not able to raise transport to come for the sessions. Although we were given a refund, we found it a challenge to raise transport that would take us to school to attend the sessions.Difficulty raising transport money combined with long distances further prevented participants -and their family members- from either arriving to the sessions or arriving on time. For example, Violet noted that while the sessions were scheduled at the right time, they usually arrived late because they were coming from far. Joseline noted that she initially lived in a place that was farther away from where the sessions were held and the transport was costly. Hence, she missed some sessions. Eventually, she moved closer to the delivery location.Joseline: In the beginning I was staying in another location that was far and the transport cost was high. They used to charge me twenty five thousands [Uganda Shillings]. I missed some [sessions] because there was a time when they invited me but I was in that far location and I could not attend.Ruth, however, noted that she was not very interested in attending the sessions and that during the heavy rains, her guardian had to push her to attend the sessions.Ruth: Sometimes I liked playing more than coming to the sessions because I didn’t like them that much even though they were intended to help me. One day, it rained heavily, and the weather was bad. I didn’t want to come but then my guardian came and told me that we had to go. I went forcefully just because he had sacrificed his time to come.Participants mainly had positive responses to the group format. They appreciated that families could easily share their experiences, and sometimes use the group to help resolve issues. For example, Annah appreciated the group format because it facilitated knowledge sharing and learning between families.Annah: It was very good because you could share knowledge and be able to get different ideas about something. People would raise their hands and give different opinions about something so there was knowledge sharing and we could learn from one another.Ruth shared similar sentiments and added that they felt comfortable sharing with the group even when it was challenging.Ruth: It [the group] was amazing to us because everyone would share their family experiences and we could discuss them. Sometimes one would say that in their family, they don’t go to bed without saying prayers and we could all get to know it. We always felt comfortable sharing with our colleagues even if something was challenging.Mary noted that sharing experiences helped them learn from one another and made her feel comfortable. She also appreciated that everyone was given the chance to speak.Mary: Everyone was given a chance to share their ideas. People from different families used to share their experiences and this helped us to learn from one another on the day’s topic…The way we used to share our own experiences made me feel at ease and to make the groups lively…“Everyone learned from another and those who weren't confident gained it in that a person could say; if this person has managed to stand and give her view, why can’t I do it also.”Similarly, Gloria acknowledged learning from each other and went on to discuss how being in a group helped others to gain confidence in sharing her thoughts and experiences, While Janet liked having other families in the group, she was less comfortable when a group member came with a family member other than the one that they usually attended with. She was worried that these people would not respect the confidentiality of the group and spread rumors in the community.Janet: Sitting together with other family members was not bad because we were used to one another but if someone comes with “a forged guardian” because the real guardian has not turned up, I didn’t like it. Coming with a different family member in the group was not right because after departing, they will go and start spreading rumors of what has been shared in the group which is not good.Most study participants had a positive experience with attending sessions together with their caregivers. They mentioned that being with their caregivers in the sessions helped them to learn together, receive support when needed, and in some cases change their caregivers’ minds. Grace shared that they used to sit at the same desk with her caregiver, and this made it easy to consult with her caregiver in case they asked something she did not know. Janet also felt good sitting with her family members because it helped them to reconnect.Janet: I felt good because we take long without sitting together as family members. Everyone is usually on their own. This time helped us to come together as a family to discuss different topics and to be socially connected.Annet felt that attending the sessions together with her guardian helped to support the idea of starting an income generating activity. The sessions reemphasized how this was important and doable, and she was happy that her guardian was part of the training.Annet: These sessions did so well to train and equip us with the skills because even our guardians could not tell us that we can do this to get money. Before, they could not allow us to start up small businesses because they thought we would get spoiled. They used to tell us to wait until we finish school and start up something. After the trainings, our parents can now allow us to start up something.“there was a lot to learn for a child and a guardian, making decisions together and agreeing with one another.”Mary thought that attending the MFG sessions with the guardian because On the other hand, while Christine enjoyed coming to the sessions with her caregiver, she did not enjoy when adolescents and caregivers completed certain activities separately. She thought that it was not the best use of anyone’s time with group members moving from one place to another.Christine: We could reach a session, that children would sit by themselves and parents alone, and then for me, I did not like that moment a lot because you would be seated and then they say, go and sit somewhere else, when every child as to sit with their parent and then they tell you that those that side, stay alone and even those the other side. That thing of moving and time used to be wasted there.“The venue was so good. The class was wide, and everyone had a right to sit anywhere they wanted as long as you are seated in a circle and you’re able to listen to what is being discussed.”.Sessions were conducted at schools. The research team worked closely with the school contact teachers and head teachers to identify and prepare classrooms prior to the sessions. Both Janet and Mariam noted that the location was noise-free, the classroom was spacious, and there was nothing to disrupt them from learning. Fiona shared that the venue was big enough to accommodate all the participants and that they were able to sit comfortably, For Anisha, the venue was a central location for all and the transport costs to get there were not prohibitive.Anisha: The place was not bad. This is where we could all gather easily because most of us live around here and this place is in the center to where we all live so the transport cost to here was about two thousand shillings, and we could all come here.“The class for the sessions used to be clean and we could get fresh air so well, the light was good, the class was excellent.” However, she also pointed out that the space was small. Gloria reported that the bathrooms were far from where they conducted the sessions and was worried that somebody who might need to use the bathroom urgently would be inconvenienced.Racheal mentioned that the fact that sessions were conducted during the holiday break when no other students were in school, made the school a quiet place. Christine appreciated the cleanliness of the classroom as well as the light and opportunity to get fresh air: Gloria: The only issue was that the washrooms were very far and if someone had come having diarrhea to attend the sessions, would be inconvenienced. He/she may not even come back because the distance was too far.favorable because we had no classes at school. The time was okay because sometimes it was in the evenings, which enabled us to first complete housework and then go for the sessions.”Most study participants were happy with the day and times when sessions were conducted. Grace, Racheal, and Fiona noted that the session start time gave them a chance to first do some household chores before coming to the sessions. For Fiona, the day was ““disturb their brains”. Gloria appreciated that the sessions were delivered on the weekends and during the school break. In addition, there was not much farm work at the time, which allowed caregivers to attend the sessions, “we were on holidays and there wasn’t a lot of digging. So, parents didn’t have much work by then.”Harriet noted that the day enabled her to take a break from digging in the fields, which usually happened on Saturday. In addition, that allowed her to continue attending church on Sundays. For Mariam, the day was good because everyone was free and out of school. They did not have to attend classes, which helped to not While some participants were happy with the day and time when the sessions were conducted, Christine felt that sometimes attending sessions on the weekend was not favorable as she was left with no time to devote to her weekend studying.Christine: Sometimes Saturday was not a good day for me because I used not to get time to sit and study because sometimes, I would have an examination on Monday. And on Sunday, students would be on entertainment and making noise.Because the sessions required both the child and the caregiver to attend at the same time, Margret felt that this was an inconvenience as they did not want to leave the household unattended.Margret: The time in general, was not so good because sometimes, we were only two at home. If we all leave, there is not one left behind and sometimes we go back late. But it would depend on the time you would report in the morning. It was not so good, but we endured and completed.Barbra thought that the start time for the sessions was too early as it made it harder for people who were coming from more distant places and would have preferred a later start time.Barbra: The issue was about the time. We were invited to attend the trainings in morning hours at 8:00 am. This was not favorable for people who were coming from afar. If the time was 10: 00 am at least, this would enable someone to first finish some home chores and then attend the trainings.They would answer any question and they were giving everybody a change to share their opinion. They would welcome every answer whether it is right or wrong.” Similarly, Sarah shared that the facilitators were very well trained, which enabled her to share some of what she learned with other members of her family.Participants appreciated that the facilitators were knowledgeable and prepared. They related well with the group and encouraged them to share their opinions during discussions. For example, Janet noted that the facilitators’ interactions with the group were good and they did not show any signs of favoritism. Rose talked about how facilitators encouraged everyone to share their opinions, “Sarah: I thought of them as being well trained and conversant with the information which they had to share with us. They were able to give us very helpful information, which information we were also able to share with other members of our families.In addition, Mariam noted that the facilitators provided detailed explanations, they treated everyone with respect, were not rude and made sure everyone understood the content before moving on. Facilitators’ respectful attitude was mentioned by many, including Flora.Flora:that they were going to be very strict but they were not. I thought that they will shout at us and force us to do things, but they were peaceful. They were polite and when you talk to them, even when you give them a wrong answer, they will explain to you and make sure that you are not left behind”.Both Violet and Jennifer shared that the facilitators patiently repeated the content and made sure that everybody understood it. Violet added that they respected everyone’s opinion.Violet: They facilitated us so well. In case someone went out or had not understood, they would repeat for them such that they understand it clearly. They respected everyone’s opinion, whenever someone was speaking, they could listen carefully. They would explain every point and ensure everyone understands it. They treated us fairly without discrimination. Everyone was given chance to present their views.“The other thing that helped was having two facilitators. One would concentrate on one family and the other one would also be demonstrating something to another family as well. It was helpful to have two facilitators in a group.”Barbra noted that having two facilitators in the session was helpful so that they could attend to different families when needed: "All of them worked as a team. One could advise each other, and they properly communicated with each other.” For Ruth, the fact that they treated each other with respect and helped each other was good role-modeling for her.Some participants also appreciated the facilitators’ relationships with each other. Racheal added, Every time we attended, I could learn what to do. We learnt them and I didn’t take them for granted because they were beneficial.” She went on to add that she was able to start an income generating activity that made both her and her father happy.Participants found the content covered in both FLT &IGA and MFG sessions were relevant and helpful. For instance, Racheal shared that every time she attended a session, she learned something beneficial, "Racheal: What made me happy was the fact that one was able to start an income-generating activity. My father was very happy because I didn’t have that knowledge before but when he saw that I had started trading in sugarcane, he said that his daughter had acquired great knowledge.Mariam appreciated the opportunity to learn about income generating activities. When asked about what in particular, she emphasized that it was important for her to understand budgeting and learn that she could start a small business even with the little money that she had.Mariam: I learned that even if you have little money, you can start up your small business and keep adding in slowly by slowly. I learned how to spend money. Sometimes you have to first make a budget and save and invest other money in the business. I developed more different kinds of perceptions on how to handle my business.Being able to have a bank account and save made Annah proud. Having a bank account at a young age made her feel different than her peers.Annah: I never thought that at my age I can own a bank account, that interested me so much. To save money in the bank, made me different from my friends. They see that you are different from them, at my young age yet some older people don’t even own a bank account, which makes me different.Sarah felt like learning to save money gave her a roadmap to solve her problems: “The skill that has been most helpful to me is saving money, which you can use to solve a problem that arises.” Violet also shared that the sessions taught her to plan for unanticipated problems.Violet: We learned a lot from the FLT sessions because we never knew the importance of saving for the future and unanticipated situations as well as starting up income-generating activities. They taught us that before saving, one should have the right budget. You have to first set aside money to cater for unanticipated problems and basic needs and then save the balance.Participants also appreciated the content they learned during the MFG sessions. For instance, Agnes shared that she learned about preventing STIs, including HIV as well as good communication and relationships among family members. Similarly, when asked about the most exciting content she learned in the sessions, Sarah shared:Sarah: About the different viruses that transmit sexually transmitted diseases and we all appreciated the need to protect ourselves as children. I applied the skills by avoiding behavior that puts my life at the risk of contracting sexually transmitted diseases and by appreciating the need to save money.Mariam was able to use the content and skills she learned during the MFG sessions to settle arguments among her siblings.Mariam: If there is a situation when they are quarreling, I can calm them down and tell them what we learned from the sessions. I can explain to them and sometimes they forgive each other. Sometimes when the mother is upset and she starts to quarrel, you can remind her of what was taught in the sessions.Anisha found the rules to be helpful. She added that her older sister who was attending the sessions changed the way she was doing certain things.Anisha: Since my older sister was also attending the sessions, she changed her way of doing certain things, for example, before the sessions, she would always accuse me of messing up but after the sessions, she learned that all children can mess up and that she should establish who messed up before accusing just one person.“this made some of the students to say that I am a coward because I just kept quiet.”However, she also noted that there were instances where she chose to stay quiet in some situations instead of arguing at school and Many participants noted positive changes after the MFG sessions. Barbra shared that her parents communicated better with each other as a result of the sessions.Barbra: Before the trainings, mom and dad would get angry at each other and they would keep the anger for a long time but after attending the training sessions, they sit down and solve the issue every time there is a misunderstanding.Grace was the only participant who felt like the content was particularly helpful to her family.Grace: I have applied skills of having good relations at home for example gardening together, fetching water together, and in this case, we work together such that we rest at the same time. The information was good, however much it didn’t work well in our family.In this study, we explored the acceptability of the Suubi4Her combination intervention comprised of economic empowerment and family strengthening components among adolescent school-going girls in Uganda. Specifically, we explored motivations to and initial concerns about Suubi4Her program participation, barriers and facilitators to session attendance, and feedback on intervention characteristics, including content relevance, all aspects relevant to program acceptability.Adolescent girls were motivated to participate in Suubi4Her and underlined different aspects of the program as motivating factors for them, including information about STIs and HIV as well as pregnancy. For some, HIV, STI, and pregnancy testing was also important as that would allow them to plan accordingly, as also identified by Ferrand et al.  as a reaWhile more than half of the participants did not have any initial concerns about participating in the program, a few concerns were brought up. Some participants were worried about not being able to fulfill the requirements of the program, such as pulling together the necessary paperwork for opening bank accounts while others worried that they would not be able to save or deposit. A few participants mentioned that there was some distrust in the community or among caregivers toward the program. Community distrust has been discussed in the context of health and mental systems –48 as weWe also inquired into the facilitators and barriers to program attendance. One of the main facilitators to attending sessions was to learn new things. Participants thought that the knowledge they gained from the sessions was too important to miss. Hence, they rearranged their other chores to make sure they could attend. Reminder calls from the study team as well as parental commitment also helped them to prioritize the sessions. These findings suggest that even when the experienced opportunity cost was high for some participants, they chose to make compromises to stay engaged. On the other side, not everybody was able to adjust. Adolescent participants mentioned family commitments and chores as a barrier to program participation, as also identified in other studies , 54. AnoAdolescent girls provided feedback on the different characteristics of the program. Overall, they found the location and time of session delivery convenient. They appreciated the group format as that allowed them to learn from other families. They also welcomed attending the sessions with their caregivers as that provided the opportunity to spend time and learn together. Intervention facilitators were perceived as helpful, inclusive, and respectful. Finally, adolescent girls found the session contents highly relevant to their families’ needs and noted positive changes in their families, including saving and improved family relations. Perceived relevance of content has been cited as an indicator of intervention acceptability in other studies as well –58. WhilOverall, our findings suggest that adolescent girls found the Suubi4Her combination intervention highly acceptable, an important and promising step for its uptake and scalability in the region and beyond, while also pointing to certain barriers that need to be taken into account. Study results need to be interpreted in light of study limitations. The qualitative interviews were conducted cross-sectionally upon completion of the intervention. Hence, the data do not capture any changes that may occur in adolescents’ perspectives on their experiences with the intervention over time. Additionally, the TFA was used at the stage of data analysis, rather than at the stage of developing the interview protocol. Relatedly, certain constructs such as ethicality and intervention coherence were not explored in-depth during data collection. However, these findings contribute to the scarce literature on intervention acceptability among adolescents in sub-Saharan Africa. Another strength of the study is the sampling strategy that allowed us to capture the experiences of both those who fared well on the targeted intervention outcomes as well as those who did not.Interventions targeting adolescent health and social outcomes are more likely to succeed if they are found acceptable by the youth that they are intended for. Our findings provide important insights into the acceptability of a combination intervention among adolescent girls, and relatedly, potential for sustainability and scalability. These findings also have important programmatic and policy implications in Uganda, especially given the higher rates of HIV prevalence among adolescent girls in the country. The Uganda Government and Ministry of Health identify adolescent girls and young women as one of the priority groups targeted by combination HIV prevention, care and treatment, and social support interventions, as outlined in strategic action 3.2.2 of the National Strategic Plan for HIV and AIDS . As such


Additionally, turn section times were faster for short-, i.e., 100 and 200 m, than middle- and long-distance races, i.e., 400 to 1500 m races (p < 0.001). Regarding variation in turn performance, finalists showed lower CVs and ∆% for all turn section times (0.74% and 1.49%) compared to non-qualified swimmers . Similarly, long-distance events, i.e., 800/1500 m, showed lower mean CVs and higher mean ∆% (0.69% and 1.93%) than short-distance, i.e., 100 m events . Regarding turn sections, the largest CV and ∆% were found 5 m before wall contact (0.70% and 1.45%) with lower CV and more consistent turn section times 5 m after wall contact (0.42% and 0.54%). Non-qualified swimmers should aim to match the superior turn performances and faster times of finalists in all turn sections. Both finalists and non-qualified swimmers should pay particular attention to maintaining high velocities when approaching the wall as the race progresses.Turn performances are important success factors for short-course races, and more consistent turn times may distinguish between higher and lower-ranked swimmers. Therefore, this study aimed to determine coefficients of variation (CV) and performance progressions (∆%) of turn performances. The eight finalists and eight fastest swimmers from the heats that did not qualify for the semi-finals, i.e., from 17th to 24th place, of the 100, 200, 400, and 800 /1500 m  freestyle events at the 2019 European Short Course Championships were included, resulting in a total of 64 male  and 64 female swimmers . A linear mixed model was used to compare inter- and intra-individual performance variation. Interactions between CVs, ∆%, and mean values were analyzed using a two-way analysis of variance (ANOVA). The results showed impaired turn performances as the races progressed. Finalists showed faster turn section times than the eight fastest non-qualified swimmers from the heats ( In highly technical sports, such as swimming, overpacing at the beginning of the race may dramatically interfere with swimming technique towards the end, hence impairing movement efficiency . Faster The coefficient of variation (CV) has typically been used to investigate the intra-individual variation in the performance of short-, middle-, and long-distance swimming events ,6,7,8,9.r = 0.83) [Variation and pacing patterns in turn performance may be particularly important success factors regarding short-course races (25 m pool length) due to the high contribution of turn performances (up to 56.08 ± 0.28% in 1500 m freestyle) to race time . The pus = 0.83) . A new p = 0.83) . On aver = 0.83) . Indeed, = 0.83) .As turn performances provide important success factors for short-course races ,19,20 anThe present investigation analyzed the turn performances of 128 races from the 2019 European Short-Course Championship. The eight finalists (Performance Level 1) and eight fastest swimmers from the heats that did not qualify for the semi-finals, i.e., from 17th to 24th place (Performance Level 2 ) of the kinovea.org, accessed on 10 August 2020). Markings at the lane ropes were used to identify when the top of the swimmer’s head passed 5 m before and 5 m and 10 m after the pool wall. Contact of the feet with the wall following the rotation of the flip turn determined the end of each lap. The video time code was exported down to a thousandth of a second, and turn split times were calculated in a spreadsheet . Turn split times were defined as IN-5m , OUT-5m , OUT-5–10 m , and OUT-10m . Previous studies reported breakout distances of 7.76 ± 1.88 m to 5.48 ± 0.87 m in 100 m and 1500 m freestyle races, respectively [The swim races were video monitored using a 12-camera system . Ten moving view cameras  followed the swimmers on each lane individually. Two fixed cameras were positioned at each end of the pool at a 90° angle and monitored the starts and turns across all lanes from the side. All cameras were synchronized and collected video footage at 50 Hz. Final standings and race times for each event were provided by the official timekeeper of the championships . Subsequently, video footage was digitized manually using video analysis software . Shapiro–Wilk and Levene tests confirmed the assumptions of normality and homoscedasticity, respectively. All the analyses were conducted separately for both sexes . CVs forg effect . All staThe results of the linear mixed-effects model analysis, intra-individual CVs, and ∆% throughout the race are presented in ANOVA testing revealed significant differences in mean turn section times, CVs, and ∆% between performance level and race distance . In genePost-hoc comparisons of mean section times showed differences in all variables and both sexes between all race distances (p < 0.03), except for OUT-5m between 400 and 800 m in women (p > 0.05). Regarding intra-individual CVs in men, Bonferroni comparisons showed differences between 100 and 1500 m for OUT-10m, OUT-5-10m, Total-10, and Total-15 . Additionally, differences in OUT-5-10m between 100 and 200 m (p = 0.009), as well as 100 and 400 m (p = 0.002) were significant. Significant differences in Total-10 and Total-15 were displayed between 200 and 400 m  and 200 and 1500 m .All differences, specific CVs and ∆% are displayed for performance level and race distance for both sexes in p = 0.024; p = 0.030; p = 0.031; p = 0.001, respectively) for IN-5m, OUT-10m, Total-10, and Total-15. There were also differences between 200 and 400 m for IN-5m, OUT-10m, and Total-15 section . The IN-5m and Total-15 section times showed differences between 200 and 800 m , as well as Total-10 and Total-15 showed differences between 100 and 800 m .Bonferroni comparisons of intra-individual CVs in women showed differences in CVs between 100 and 400 m . Additionally, there were differences in Total-10 between 100 and 200 m (p = 0.021), as well as 100 and 400 m (p = 0.015). Furthermore, there were significant differences in OUT-5-10m between 200 and 1500 m (p = 0.040). In women, Bonferroni comparisons for ∆% showed differences between 100 and 200 m for OUT-5m, OUT-5-10m, and Total-15 .In men, Bonferroni comparisons for ∆% showed differences between 100 and 1500 m for IN-5m, Total-10, and Total-15  and slow  swimmers, ANOVA comparisons were limited to a low number of subjects (n = 8). Future studies could use regression analyses to compare effects across a larger sample size. Further limitations are the missing breakout distances, which provide key performance indicators for turn performances . While oThe wall exit variable OUT-5m showed low-performance variations across all race distances and performance levels. Due to different biomechanical constraints, i.e., wall thrust, streamline position, and underwater kicking, these turn sections seemed less affected by fatigue throughout the races. As finalists showed superior turn performances, non-qualified swimmers should aim to match the faster times of finalists in all turn sections. The largest intra-individual variation and differences between performance levels were found for IN-5m, which involves the timing of the wall approach and rotation of the body. Therefore, both finalists and non-qualified swimmers should pay particular attention to maintaining high velocities in the first section of the turn when approaching the wall as the race progresses.From a practical perspective, coaches should adjust the wall approach strategies of their swimmers (IN-5m) according to individual technical and biological characteristics, i.e., sex, body height, race pace, and stroke length. In particular, timing and distance to the pool wall when initiating body rotation for the flip turn requires practice at swimming velocities specific to the race pace. Although lower variations were found in the wall exit phase, explosive push-off from the pool wall, streamline abilities during the gliding phase, and underwater undulating kicking affect turn performance and require particular attention during practice ,51,52.


The possibility of creating antennas of the 5G standard (5.2–5.9 GHz) with specified electrodynamic characteristics by printing layers of variable thickness using a graphene suspension has been substantiated experimentally and by computer simulation. A graphene suspension for screen printing on photographic paper and other flexible substrates was prepared by means of exfoliation from graphite. The relation between the graphene layer thickness and its sheet resistance was studied with the aim of determining the required thickness of the antenna conductive layer. To create a two-sided dipole, a technology has been developed for the double-sided deposition of graphene layers on photographic paper. The electrodynamic characteristics of graphene and copper antennas of identical design are compared. The antenna design corresponds to the operating frequency of 2.4 GHz. It was found that the use of graphene as a conductive layer made it possible to suppress the fundamental (first) harmonic (2.45 GHz) and to observe radiation at the second harmonic (5.75 GHz). This effect is assumed to observe in the case when the thickness of graphene is lower than that of the skin depth. The result indicates the possibility of changing the antenna electrodynamic characteristics by adjusting the graphene layer thickness. The widespread introduction of the Internet of Things (IoT) poses the challenge of introducing new materials into telecommunications instead of such conductors as copper and silver. These materials are subject to the requirements of environmental friendliness and low cost, along with the requirements of high electric conductivity and mechanical flexibility. Nowadays, flexible and wearable electronics for individual medicinal devices, remote monitoring of different parameters, as well as for ensuring safety in emergency situations are intensively developed. According to estimates, graphene satisfies the basic requirements for antenna materials. Moreover, graphene conductivity has been continuously increased due to the progress in graphene fabrication technologies ,2,3. GraIn the decimeter range, the depth of the electric field penetration into films printed using graphene flakes is tens of microns. Therefore, the authors developing graphene antennas tried to make them thick enough so that they were similar in their parameters to metal ones and had low resistance, for example, ,7  and the observation of radiation at the second harmonic (5.75 GHz) was found.®-Werke GmbH & Co. KG, Staufen, Germany) in a water–ethanol solution at about 20,000 rpm. The methods of a graphene suspension fabrication are described in more detail in [The basis for the ink used for antennas was a suspension of the few-layer graphene flakes with a thickness of 0.5–3 nm and a lateral size less than 2 μm. The graphene suspension was created from natural purified graphite using electrochemical exfoliation and subsequent processing with an IKA Ultra-Turrax T18 digital laboratory disperser . This package allows one to carry out high-precision 3D modeling of the design of objects for operation in the microwave range, as well as to study their electrodynamic characteristics in accordance with the design. The characteristics of both ideal and real objects (taking into account the energy losses) were modeled.2/Si substrate had a resistance of ~50 Ω/sq, and the surface roughness on the area of 2 μm × 2 μm was 3 nm  along the antenna area. The antenna edge relief did not exceed 50 μm, as can be seen in The 60 nm thick films made of graphene suspension on a SiO3 nm see a. PrintiGr, in a wide range of layer thicknesses from 3 to 104 nm, is presented on the double-logarithmic scale in Gr) = (4.758)/(Lg(d))0.557. The deviation of the curve for graphene from a linear dependence is attributed to the variation of the graphene layer resistivity with their thickness. Strong variation in the resistivity of a graphene–graphite layer on the thickness was theoretically justified in Ref. [Cu = 5.96 × 107 S/m except for the near-surface skin depth with higher resistance and a thickness of several Angstroms. As a result, the volume part of Cu resistance RCu = f(d) in the double-logarithmic scale of 5. Thus, the graphene curve was obtained from experimental data; for copper, the curve was calculated. The sheet resistance of the printed graphene layer, R in Ref. . It is wThe strong graphene-graphite layer resistivity dependence on the thickness opens up new possibilities for the antenna design by means of changing the active layer thickness. This statement is demonstrated in the present study on the example of a two-sided symmetrical dipole in which, using the layer printed from graphene flakes, the first radiation harmonic was suppressed and significant radiation at the second harmonic  was found. All modeling and experimental studies were carried out on graphene and copper antennas, which are of identical design.To demonstrate the possibility of controlling the antenna electrodynamic characteristics using the graphene printing technology, the antenna design that could be used as an element of the Internet of Things in the 5G range of mobile operators was chosen. At present, the frequency band of 5.2–5.9 GHz is being mastered for these purposes. Graphene is an environmentally friendly material. That allows one to make the antenna environmentally friendly by using an environmentally friendly substrate. Environmental friendliness is one of the main requirements for IoT elements because, according to , the mas4 S/m.With the help of computer simulation in the CST package, the design of antennas, calculation, and study of their electrodynamic characteristics were carried out see . The conThe total power supplied to the antenna (the standard term-incoming power) includes the power reflected from the input (reflected power) and the power received at the antenna (accepted power), which is spent on radiation (power radiated) and antenna losses (power losses) b. The ma8 S/m. The CST software package, using the power view calculation module, allows us to better understand the behavior of the antenna by analyzing the power balance. A power analysis was performed only for two frequencies, 2.6 and 5.7 GHz. A Gaussian stimulus waveform was used to perform power analysis, CST automatically calculates the appropriate excitation time pulse based on the frequency range setting. The CST transient solver works with time pulses that can be easily converted to the frequency domain using the fast Fourier transform.The antenna conductivity in the CST simulation package model was changed from 10 to 105 S/m), there is good input matching for both frequencies. The reflected powers are not large, but the reflected power at a frequency of the 5.7 GHz is less than for the 2.6 GHz and is close to zero for the material with the conduction of graphene σ = (0.5–1.0) × 105 S/m. In The accepted and reflected powers’ dependence on the specific conductivity for ACu antennas is shown in The characteristics of the antennas were measured with a complex of transmission and reflection vectormeters in an anechoic chamber. To eliminate the need for tuning when measuring the radiation pattern, RP, a P6-32 broadband measuring antenna, was used as a standard. To determine the gain factor, the comparison method with the reference measuring antenna was utilized. The data for the voltage standing wave ratio VSWR and the calculated and measured reflection coefficients S11 are shown in As is seen in The calculated reflection coefficient S11 for AGr and ACu is shown in The normalized radiation patterns in polar coordinates in In the evaluation of the RP deviation of experimental samples from the RP of computer models, the given radiation patterns confirm that the operating frequency in the AGr antenna is the second harmonic of 5.7 GHz. The measurements also show that, within the passband, the RP is weakly dependent on the frequency. The appearance of directivity in the diagram of the AGr antenna at the frequency of 5.7 GHz is an unexpected experimental fact. A radiation pattern in the H-plane also confirms this statement. Experiments in the anechoic chamber with variable angle steps also confirm this result. The physics and the theory of this phenomenon have not been developed yet and require further studies.The experimental results obtained for the radiation pattern and the gain factor of the AGr antenna made it possible to determine its efficiency for the 5.7 GHz band using the technique suggested in Ref. . As the A prototype of the graphene flexible eco-friendly resistive antenna and its analogue with a copper conductive layer was created, and the electrodynamic characteristics of a graphene printed two-sided symmetric dipole and its copper analogue, created on the basis of computer simulation, were studied. It was shown that the variable resistivity of graphene leads to suppression of the first radiation harmonic of 2.6 GHz, which is the main one for a copper dipole. In this case, in the graphene dipole, the second harmonic of 5.7 GHz becomes the fundamental harmonic (band of cellular operators 5G). The result is confirmed by the experimental data for VSWR, reflection coefficients, and antenna pattern. The performance of the symmetric two-sided graphene dipole is confirmed by the experimental measurements and the calculation of the power distribution depending on the layer conductivity in the range of specific conductivity variation of eight orders of magnitude.The dependence of the surface resistance of the printed graphene layer is non-linear. Its specific conductivity does not remain constant but depends on the layer thickness. Therefore, the result indicates the possibility of varying the antenna electrodynamic characteristics using the graphene layer with relatively high resistance and a thickness lower than the skin depth. The effect has been obtained using graphene with a relatively high resistivity, but the development of new graphene-based materials with lower resistivity could expand the capabilities of this method. Moreover, the use of thin graphene layers leads to the possibility of creating a flexible antenna.