Electronic prescribing and medication administration systems are being introduced in many hospitals worldwide, with varying degrees of clinical decision support including pop-up alerts. Previous research suggests that prescribers override a high proportion of alerts, but little research has been carried out in the UK. Our objective was to explore rates of alert overriding in different prescribing situations and prescribers’ perceptions around the use of decision support alerts in a UK hospital.We conducted a mixed methods study on three cardiology wards, directly observing medical and non-medical prescribers’ alert override rates during both ward round and non-ward round prescribing; observations were followed by semi-structured interviews with prescribers, which were then transcribed and analysed thematically.2 test). While respondents acknowledged that alerts could be useful, several also described negative unintended consequences. Many were of the view that usefulness of alerts was limited if the alert was reminding them to do something they would do anyway, or suggesting something they did not feel was relevant. Findings suggest that targeting, timing and additional features of alerts are critical factors in determining whether they are acted on or overridden.Overall, 69% of 199 observed alerts were overridden. Alerts experienced during ward rounds were significantly more likely to be overridden than those outside of ward rounds (80% of 56 vs 51% of 63; p=0.001, ΧThe majority of alerts were overridden. Alerts may be less likely to be overridden if they are built into the prescribing workflow. Electronic prescribing and medication administration (ePMA) systems are increasingly prevalent in the inpatient setting. ePMA systems generally incorporate clinical decision support (CDS) aimed at aiding prescribers in prescribing safely, such as drug dictionaries, default dose suggestions, drug-drug interaction alerts, drug-allergy alerts and alerts to relevant laboratory results.There is some evidence that ePMA incorporating CDS alerts reduces medication errorsThe majority of the research in this field has been conducted outside the UK, and may not be generalisable to the UK due to differences in the way medicines are prescribed, dispensed and administered.The study took place in a 349 bed London teaching hospital during November and December 2016. Inpatient ePMA had been introduced a year previously as part of a commercially available electronic patient record system. There were two types of pop-up alert in use. These appeared either when the patient details were accessed (type 1) or when the medication page was opened (type 2). Type 1 alerts, such as the antibiotic review alert, continued to be displayed until they had been acted on. To access the patients’ details the user could acknowledge the alert, which meant it would then appear again next time the patient’s records were accessed. Type 2 alerts required action before medication could be prescribed. For example, the venous thromboembolism (VTE) risk assessment alert could be closed either by completing the VTE assessment or by clicking an override button and giving an override reason.At the time of the study, one type 1 and five type 2 alerts were in use. The study took place on three cardiac wards: cardiothoracic , cardiology  and cardiothoracic critical care . On ward A, advanced nurse practitioner independent prescribers did a considerable proportion of prescribing, whereas only medical staff prescribed on the other two wards. During ward rounds, senior doctors generally made the prescribing decisions and more junior doctors or nurse prescribers carried out the prescribing tasks.This was a descriptive mixed methods study, comprising quantitative observations of ward round and non-ward round prescribing, followed by semi-structured qualitative interviews with medical and non–medical prescribers. The study was registered as a service evaluation within the hospital; no personally identifiable data were recorded for patients or healthcare professionals. Two final-year pharmacy students were trained to collect the data.Following approval from ward managers and lead consultants, individual prescribers on the study wards were given information leaflets and invited to give written consent to be observed. Observations took place every day for five consecutive weekdays on each ward, starting during the morning ward round (about 08:00 hours) and continuing until mid-afternoon (about 15:00 hours), to enable observation of both ward round and non-ward round prescribing. During non-ward round prescribing they observed prescribing in the doctors’ office, as this was where most prescribing took place. The students collected data on different wards simultaneously.We documented the frequency and types of alerts related to medication experienced, by whom, the observed actions taken and any further contextual information , alert type  and prescriber type . We used ΧInterviews were audio-recorded, anonyomised and transcribed verbatim. Inductive thematic analysis was then conducted without any pre-existing coding framework. The students reviewed the transcripts to identify recurrent themes. The interview transcripts were considered in context with observational data where prescribers had also been observed using the ePMa system. Two students analysed half of the interview data each and a researcher then checked and merged the analysis and coding.During the 15-day study period, we observed 41 hours 24 min of ward rounds and 53 hours 40 min of non-ward round activities. Eighteen healthcare professionals were observed .A total of 119 CDS alerts related to medication were observed, all of which related to either antibiotic review (n=85) or VTE (n=34). Fifty-six (47%) were observed during the ward round and 63 (53%) during non-ward round prescribing.Based on univariate analysis, significantly more VTE alerts (p=0.0003) were acted on during non-ward round prescribing than ward round prescribing . HoweverWard round versus non-ward round prescribing remained a significant variable (p=0.03) in logistic regression analysis but the difference between medical and non-medical prescribers was no longer significant due to the confounding effect of ward round versus non-ward round prescribing.Sixteen interviews were conducted, 14 with medical prescribers and 2 with non-medical prescribers. The duration of interviews ranged from 4 to 34 min. Perceived usefulness of alertsInterviewees were generally of the view that alerts could be useful and act as reminders. In particular, although not observed during our study, the allergy alert was considered helpful and important by all but one respondent who discussed this alert. The remaining respondent was of the view that it was not necessary but gave no reason.That’s always useful. That’s probably one of the most important alerts. Because when you see so many patients, in your head you know that someone has got an allergy, but what if you are doing something quickly there. (Interview 7)Two respondents also made reference to VTE assessments being important to the hospital organisation, as they received payment for their completion as part of a Commissioning for Quality and Innovations incentive target. Another respondent expressed the view that alerts could increase junior doctors’ confidence in prescribing.However, many were also of the view that usefulness of alerts could be limited if the alert was reminding them to do something they would do anyway (antibiotic review) or asking them to do something they did not feel was relevant (VTE assessment). Some respondents were of the view that medication was reviewed during the ward round already. This was particularly the case on surgical wards where it was perceived that VTE prophylaxis would always be prescribed.It makes you realize the VTE (venous thromboembolism prophylaxis) is not being prescribed for that patient but again for our setting it’s not really … relevant for us post-surgery. (Interview 16)Respondents were also of the view that alerts were only as useful as the accuracy of the information on which they were based. They were therefore dependent on fields having being correctly filled in. For example, the allergy alert would only be helpful if the allergies had been documented and the medication review alert would only be useful if the correct review date had been specified when the antibiotic was first prescribed. Some interviewees perceived that default practice was to put the prescribing date as the review date, which led to the alert popping up incorrectly and being overridden.If the person prescribing the drugs has put an inappropriate review date, then it is just really annoying. (Interview 10)Interviewees suggested that the timing of alerts and where they were placed in relation to workflow was a critical factor in determining whether they would be acted on or overridden. The allergy alert appeared when prescribers tried to prescribe a medication that the patient was allergic to, at the point of prescribing; this was considered helpful. Antibiotic review alerts appeared when a patient’s record was opened. These therefore appeared during the ward round which was considered helpful as this was when medication was typically reviewed. However, some respondents were of the opinion that it would be even better placed at the point of opening the patient’s medication prescribing screen as it would then appear at the time medicines were specifically being discussed. The VTE assessment was considered by respondents to be in an incorrect place in the workflow as it appeared when medicines were being prescribed. Medicines were typically prescribed by junior doctors during the ward round and they had insufficient time to carry out the VTE assessment before the ward round moved to the next patient. The assessments would be completed as a task in the afternoon and respondents suggested that it was at this point that a reminder may be more helpful.Unless you are doing the assessment on the ward round, which no one does, because we are trying to get drugs written and trying to do loads of different things. What it ultimately is… it’s almost like it’s set up to not be successful… I just think the timing is probably not appropriate. (Interview 15)In addition to the timing of alerts, it became apparent from the analysis that they also needed to be targeted to the right person, for example, junior versus senior staff, and the patient’s regular clinical team versus on-call staff who may not know the patient as well.That was the first time I was meeting that patient and I didn’t know enough of the background to be able to fill out the VTE (venous thromboembolism) prophylaxis form accurately. (Interview 11)Interview data also suggested that alerts were more likely to be acted on if they were user-friendly. Specific improvements suggested including links from the antibiotic review alert to the antibiotic prescription concerned, and making the VTE form more accessible as a quick link as part of the alert.Overall, views on the effects of alerts on patient safety were mixed. While it was acknowledged that alerts could bring important safety-related information to the attention of prescribers, several respondents described negative unintentional consequences of the alerts. These included loss of concentration leading to medication errors, delays in prescribing urgent medication and intended medication not being prescribed as a result of the override button not being pressed. These negative consequences were described frequently in relation to the VTE alert as this popped up for every medicine prescribed and the medicine could not be prescribed until the VTE assessment was completed or the override button was pressed and a reason given.You can sometimes get to the point where you are clicking without sometimes looking, if you have just prescribed a whole stack of drugs, er, and you are trying to get them onto the system, so I have on occasion forgotten to switch the radio (override) button and someone wandered up to me and said why is their potassium replacement not prescribed and then I think oh I’ve prescribed everything but not this one because I’ve forgotten to switch the radio (override) button to emergency override. (Interview 13)Triangulation of quantitative and qualitative data suggests that putting alerts in the correct place in the prescriber’s workflow would facilitate their being acted on. VTE assessments were significantly less likely to be acted on if they appeared during a ward round than during non-ward round prescribing, whereas there was no significant difference between the number of antibiotic review alerts acted on during ward round and non-ward round prescribing. Interview data suggest that the reason for this difference was that medication was reviewed as part of the ward round but that VTE assessments were generally carried out in the afternoon and could not easily be incorporated into the ward round.et alet alThe override rate 69%) observed in this study is consistent with previous research that has found override rates between 49% and 96%.% observeet alet alet alVan der Sijs Strengths of the study are the mixed methods approach, inclusion of observation of both ward round and non-ward round prescribing and the inclusion of non-medical prescribers, allowing comparisons to be made. The main limitations are that only one specialty area was included in one hospital using one ePMA system and we did not include weekends or explore other variables such as alert wording or positioning, nor the clinical appropriateness of the overrides observed. Prescribers may have behaved in a different way as a result of being observed, and we only observed the antibiotic review alert and VTE alert. We did not measure inter-rater reliability between observers. Our sample size was fairly small .This study has identified areas for hospitals and system vendors to address in order to optimise the way users experience and respond to CDS alerts. Specifically, our findings suggest that alerts should be targeted to the right person at the right time with electronic links to the action required where relevant. Prescribers and other users should be involved in design of prescribing workflows and the use of CDS alerts.In a small study in an English hospital we found that the majority of decision support alerts were overridden, but VTE alerts were significantly less likely to be overridden when they appeared outside of ward rounds. The findings suggest that alerts are less likely to be overridden if they are built into the correct workflows of prescribers both in terms of the timing of the alert and the healthcare professionals targeted. Findings also suggest that alerts should include links to the action needed.Research from other countries suggests that prescribers override a high proportion of clinical decision support alerts.Little research has been carried out in the UK.Override rates in the UK are similar to the other countries.The timing of alert pop ups is independently and significantly associated with whether alerts are acted on or overridden.


There are a large number of redundant transmissions in current D2D multicast content delivery systems, which seriously reduces the utilization efficiency of resources. This paper designs a novel user-information-aware D2D video distribution mechanism. More specifically, by predicting users’ video requests, the video can be pushed to potential service requesters while distributing video for service requesters. Firstly, the willingness of potential requesters to accept the pushed video is estimated based on the users’ interests, the popularity of the videos and the residual-energy of the users’ devices, and the user-demand-aware clustering algorithm is proposed. Secondly, considering social and interference information, the utility metric of D2D multicast is proposed to measure the value of content distribution service. Finally, this paper proposes a D2D video distribution mechanism to optimize the utility value. Simulation results show that the proposed mechanism significantly improves throughput, energy and spectrum efficiency compared to the traditional distribution mechanism. With the rapid development of Mobile Internet, it is estimated that mobile data traffic will increase by approximately seven times from 2016 to 2021, in which 78% of mobile data traffic is generated by mobile video services ,4. In faCooperative communication is an efficient D2D communication paradigm where devices can serve as relays for each other . The relThis paper proposes a user-information-aware D2D multicast file distribution mechanism, the video is pushed to potential service requester when distributing video for service requesters, the energy and spectrum efficiency can been improved dramatically by increasing the number of D2D multicast receivers.To guarantee the quality of experience (QoE) of potential service requesters, the willingness of potential requesters to accept the pushed video was calculated by considering users’ interest and the status information about user’s device, and then a clustering algorithm based on the user’s willingness is developed.The utility metric of D2D multicast communication is proposed to evaluate the D2D multicast content distribution service. Meanwhile, the link quality information and social relationships among users are taken into the calculation in the utility value to suit the actual communication environment.A cluster head selection algorithm is developed to maximize the utility value of D2D multicast communication.Based on the relay-assisted D2D communication and D2D multicast communication, the redundant transmission of multimedia content distribution can be reduced greatly, dramatically improving the efficiency of spectrum and energy, and further mitigating the shortage of spectrum resources. However, the relay node and cluster head node always cause excessive energy consumption during assisting content distribution and its resources also be occupied. The selfishness of the users may cause relay nodes to behave negatively in assisting D2D communication. The user’s mobility and social relationships among users can also seriously affect the data transmission performance ,11. WhatThe rest of this paper is organized as follows: the related works are introduced in In the traditional cellular communication system, an enormous number of users with the same video demands separately obtain the required content from the base station using their respective allocated bandwidth, so the base station needs to send duplicate content over different links as the multiple users initiate the same service request. Obviously, the base station performs a vast number of redundant transmissions, resulting in low video transmission efficiency, and the amount of redundancy is proportional to the popularity of the transmitted content. D2D multicast content distribution as a potential technology to reduce redundant transmissions and improve the resource utilization, has received extensive attention and research in recent years. As mentioned in In the D2D multicast communication, the cluster head node is responsible for relaying data, so the transmission performance of the content distribution system is mainly determined by the capability of the cluster head node. And the capability of cluster head includes two aspects, physical and social. In order for all receivers to receive all data correctly, the transmission rate of D2D multicast communication is determined by the receiver with the worst channel quality, i.e., the multicast communication performance is subject to the worst SINR of the receivers. In , with coThe above studies only consider the physical information. In fact, numerous studies have confirmed that the social relationship between users has a significant impact on the performance of wireless communications ,18. ClusThe social-aware file-sharing mechanism is proposed in , users wThe relay nodes can consume a large amount of energy when forwarding data for other users, but the battery capacity of relay nodes is limited. Therefore, in the relevant research areas, besides the efforts to improve the data distribution rate, delay performance, and system capacity, there are a large number of domestic and international researches which devoted to optimizing the energy efficiency of the system ,25,26. TIn order to improve the performance of D2D multicast data distribution such as throughput, spectrum efficiency, and energy efficiency, the above studies have proposed their own solutions. Nonetheless, most videos are accessed by a large number of users at any time during the day, so the same videos in the same area are transmitted multiple times at different times by using existing D2D multicast communication technology, bring about a large amount of redundant transmissions. To tackle the aforementioned redundant transmission and improve the resource utilization efficiency of the D2D multicast communication system, this paper proposed a novel user-information-aware D2D multicast file distribution mechanism, in which the video is pushed to potential service requesters when distributing video for requesters. The throughput has been improved greatly by increasing the number of D2D multicast receivers, and in turn the energy efficiency and spectrum efficiency have been improved dramatically. In the cell, the members of the D2D multicast cluster are composed of the geographically adjacent users that request the same video from the base station, and the cluster head is selected from the members of the cluster. The base station firstly sends the requested video to the cluster head through the cellular downlink, and then the cluster head distributes the video to other members via D2D multicast communication. In this way, the redundant transmission can be reduced for the same video, improving the utilization of the spectrum and offloading the traffic of the base station.SINRmin is the worst SINR of receivers, um denotes the receiver with the worst SINR, and then SINRmin can be denoted as:mu received from the cellular user, and um. Therefore, according to Shannon Theorem, the channel capacity of the D2D multicast communication can be expressed as:N is the number of receivers in the D2D multicast cluster, B is the bandwidth. Observing (1) and (2), we know the throughput can be greatly improved by increasing the number of members in the D2D multicast cluster in certain conditions, dramatically promoting the energy and spectrum efficiency.Assuming that the D2D link reuses the uplink channel resource of a cellular user in the same cell, let In the existing D2D multicast communication system, the time domain is not fully considered in distribution for user service requests. Actually, most of the users access the video at any time during the day. For the high popularity videos, the same video in the same area more likely be transmitted multiple times at different times by using existing D2D multicast communication technology. Therefore, there are a large number of redundant transmissions of the traditional D2D multicast content distribution system, the spectrum efficiency and energy efficiency of the system still can be improved.The users requesting video at the current moment are called service requesters, and the potential service requesters are defined as the users presenting the same video demands with service requesters but no initiate service requests at this moment. The distribution of users within the cell is shown as n service requesters and m potential service requesters, denoted by the set If the video is pushed to the potential service requesters when it is distributed to the service requesters, the throughput of the system will be significantly improved due to increased number of D2D multicast receivers, thereby the energy efficiency and spectrum efficiency will be improved greatly. Besides, the QoE of potential service requesters will be also improved by the suitable video push service. In fact, due to the differences of user’s interest, the residual energy of user’s device, and the status of user’s device, the willingness of each potential requesters to accept the pushed video is very different. What’s more, the channel quality and the social relationship strength among users also affect the transmission performance of the system. Therefore, the selection of both potential service requesters and the cluster head is the key to improve the transmission performance of D2D multicast file distribution mechanism. The purpose of this paper is to accurately predict the service requests of potential service requesters and formulate appropriate clustering and cluster head selection schemes to achieve system throughput, energy efficiency and spectrum efficiency improvement.The potential service requesters receiving the pushed video will consume the energy of the user’s device, occupying the device’s bandwidth and storage space. If the device’s residual energy or storage space is insufficient, or the potential service requester is using the wireless network, the user may be unwilling to accept the pushed video. In addition, the user’s subjective intention is also an important factor to affect the video push service. If the pushed video does not meet the user’s interest, the push will lose its significance, and the user’s experience quality will be seriously reduced. In order to accurately to predict user’s service requests and improve the user’s experience quality, the willingness of potential service requester to accept the pushed video is studied in this section, and then the user-demand-aware clustering algorithm is proposed.A certain video requested by users is mainly related to the user’s interest and the video’s popularity. Therefore, based on the user’s interests and video’s popularity, the calculation of video request probabilities can take into account the commonness of the video and the user’s personality simultaneously.k-th type of video, k-th type of video, and The user’s interest can be reflected by the accumulated duration information accessing video content to some extent. The larger watching times clearly indicate the higher interest degree for a certain interested video. Thus, the user’s interest in the video can be shown in (3):k-th type video and the total video views in the past period of time T, it can be expressed as:k-th type video, and iX indicates the total number of videos user T. The user’s interest can be measured more accurately by simultaneously considering the frequency information and duration information about the user watching the online videos.In fact, the duration of different videos is very different, i.e. between over two hours for movies and a few minutes for a small video, so user’s degree of interest just expressed by the ratio of viewing time is not accurate. The proportion, the number requesting this video to the total video requests, should be considered in the calculation of the user’s interest degree. Let k-th type video, and it can be given by:j-th watching the k-th type video. If In addition, the calculation of the user’s interest degree may be influenced by some interference information generated by the user’s inadvertent touch. Therefore, based on filtered this part of information, let F denotes the set of videos requested by the users in the cell over the past period of time T, l can be expressed as:Tracking the video viewing rankings of YouTube websites in different regions it was found that the popularity of videos in specific regions follows the Zipf distribution, although the popularity in different regions is different . Let F dk. The k is the category number of video The probability that a user requests a certain video is mainly determined by the user’s interest in the video and the popularity of the video. Let’s assume that the video n bits for a mobile terminal is given by:c is expressed as:In contrast to the transmitter, the energy consumption when receiving the video file mainly comes from its own power use. Therefore, according to the radio energy dissipation model proposed in , the enecated in , i.e., φIn summary, when cluster head attempt to improve throughput by pushing video As mentioned above, the probability of the user requesting a video is calculated according to the historical viewing behavior information of the user and the video’s popularity. Besides, the extra reception of the pushed video will consume the energy of the user’s device, occupying the device’s bandwidth and storage space. In order to ensure the experience quality of the potential service requesters, and avoid disturbing other unrelated users with the video push service., the probability of accepting the pushed video, named as user’s willingness Taken together, when the requesters initiate a request for the video According to the above analysis, this paper proposes a novel user-demand-aware D2D multicast clustering algorithm, which is based on the grid-based clustering algorithm, as shown in Algorithm 1. First, the willingness of the potential requester to accept the pushed video is calculated, and then the user set Algorithm 1. User-Demand-Aware Clustering Algorithm1.Input:2.service requesters set video 3.Output:4.cluster members set 5.Procedure User Demand-aware Clustering Algorithm6.fordo7.    put 8.end for9.for do10.    calculate the willingness     according to Equations (5)(6)(9)(11)11.ifthen    12.         put 13.end if    14.end for15.EndDue to the mobility of D2D users, the limited transmission capability for wireless terminal devices and the instability of wireless channels, the optimal performance of D2D communication cannot be achieved in the actual D2D communication environment, and even D2D links may be frequently broken, so the stability of the D2D link is vital to whether the D2D communication system can achieve long-term stable performance gain. In addition to the aforementioned physical domain factors, recently, the numerous studies show that the performance of D2D communication is closely related to the social relationships between users. The strength of social relationship can be reflected by the attributes of social relationship such as the degree of trust and the demand similarity. The greater the strength of social relationships, the stronger the social stability between users. The relationships between D2D communication devices in social domain and physical domain are shown in In the same grid, users are likely to request the same video file if users have similar video viewing demands, even receiving files in the same D2D multicast cluster. That’s to say, the strength of social relationships can be expressed by the demand similarity between users, and the demand similarity can be calculated from the video request probability. In the Equation (7), the probability of any user According to (14), the probability vector of user F. As mentioned, the strength of social relationships can be evaluated by the user’s demand similarity, which is more realistic than simply using user’s interest similarity. Therefore, the strength of social relationship between user The probability vector S about set Due to the non-negative probability, the product of the probability vectors requested by user In the fourth section, the probability of the user requesting the video and the willingness for the potential service requester to accept the pushed video were deduced by analyzing the user’s historical viewing information, the popularity of the video and the state information about the user’s device. Using the user-demand-aware D2D multicast clustering algorithm, the potential service requesters that satisfy the condition of the willingness threshold were selected to form a D2D multicast cluster together with the service requesters. In D2D multicast communication, the selection of cluster head has a great influence on the performance of data transmission. Therefore, in this section, we propose a D2D multicast utility metric to measure the transmission performance of D2D multicast communication, and then a cluster head selection algorithm is proposed to optimize the system’s D2D multicast utility value.D denotes the distance matrix about the user set As shown in Notably, if B is the channel bandwidth.According to Equation (2), the total throughput of D2D multicast communication is related to the number of D2D multicast receivers and the worst receive signal to interference and noise ratio. The number of D2D multicast receivers is S. The D2D multicast utility metric In fact, the throughput model shown in Equation (21) ignores the transmission performance influence by the strength of social relationships among users. As mentioned, social relationships among users, which can be described the different levels of trust, familiarity, and demand similarity among users and so on, affect the stability of D2D links. In order to accurately measure the transmission performance of the D2D multicast communication system, the D2D multicast utility metric The D2D multicast utility metric, an evaluation metric for D2D multicast transmission performance, reflects certain information such as D2D multicast transmission rate and system throughput. From Equation (22), the value of D2D multicast utility metric is mainly determined by the strength of social relationships and channel quality between the cluster head and other members. Due to the different social relationships among users, each user shows different degrees of social activity, namely some users have poor social relationships with other members, while others have strong social relationships. Obviously, the latter are more suitable as a cluster head user in D2D multicast cluster. What’s more, due to the differences in user’s relative distance and channel characteristics, the selection of cluster head affects the change of the worst signal to interference and noise ratio , and then the channel quality matrix By the above analysis, this paper proposes a cluster head selection algorithm to maximize utility value, in which the physical information of links and the social relationship information among users are considered. The details are shown in Algorithm 2.Algorithm 2. Utility Optimal Cluster Head Selection Algorithm1.Input:2.D, video request probability users set vector is the optimal cluster head3.Output:4.optimal cluster head selection scheme5.Procedure Utility Optimal Cluster Head Selection Algorithm6.fordo7.fordo    8.         calculate the strength of social relations         and calculate the signal-to-interference noise ratio         to Equation (18)9.end for    10.end for11.fordo12.    calculate the utility metric 13.if    14.        Let 15.end if    16.end for17.output the optimal cluster head 18.EndIn this section, the performance of the proposed user-information-aware D2D multicast file distribution mechanism is evaluated by using MATLAB. In the proposed file distribution mechanism, the video received by the service requesters is pushed to the potential service requesters so as to improve the throughput of the D2D multicast transmission system, further increasing the spectrum and energy efficiency. Therefore, in the experimental scheme, the value of D2D multicast utility metric and transmission rate in different communication environments is mainly compared. The relationships among the transmission performance, the number of potential service requesters To fully verify the performance of the proposed clustering and cluster head selection mechanism, the proposed algorithm is simulated in different communication environments and compared with other schemes in the same communication environment.● Scheme 1: Based on user information awarenessThat is the proposed scheme in this paper, the nearby service requesters and the potential service requesters who satisfy a certain conditions constitute a D2D multicast cluster, and cluster head is selected by maximizing D2D multicast utility metric.● Scheme 2: Based on social-aware method D2D multicast cluster consists only of the nearby requesters and the user who has the most stable social relationship with other users is selected as the cluster head.● Scheme 3: Based on interference awareness The nearby service requesters constitute a D2D multicast cluster, the user who has the most stable links is selected as the cluster head.● Scheme 4: Random cluster head selectionD2D multicast cluster is composed of the nearby service requesters, the cluster head is randomly selected in D2D multicast cluster.Scheme 2 and Scheme 3 are typical solutions in the existing D2D multicast communication research, involving the user’s social information and channel quality information about users, respectively. The above two kinds of information are considered in the proposed user-information-aware D2D multicast file distribution mechanism. In fact, the basic principles of the first three schemes are the same, all of which can improve the system throughout by increasing the number of multicast receivers in the cluster, so Scheme 2 and Scheme 3 are selected as the comparative experimental scheme in this paper.Considering a single-cell model, users are randomly distributed within the grid, and the locations of users follow the Homogeneous Poisson Point Process (HPPP) . In addiObviously, the number of the potential service requesters is a key factor influencing the performance of user-information-aware D2D multicast file distribution mechanism. To explore the relationship between the performance of the proposed mechanism and its own parameter settings, the performances in different communication environment of the proposed mechanism with different number of potential service requesters are studied in this section. As shown in As shown in the As shown in The relationship between utility value and the number of videos Through the above experiments and analysis, the D2D transmission performances of systems with different numbers of potential service requesters in different communication environments are clarified. In general, the parameter setting has a great influence on the system performance and the more potential requesters, the better the utility value for the system.In the above The relationships between utility value and the number of service requesters are shown in As shown in For the proposed scheme, when As noted above, when the number of video files To summarize, in the proposed user-information-aware D2D multicast file distribution mechanism, the video is pushed to potential service requesters when distributing video for service requesters. Therefore, the number of the D2D multicast receivers is far greater than the other three schemes, and it is easier to select a more suitable cluster head, resulting in a better utility value compared with the other three schemes. In other words, the efficiency of spectrum and energy are improved greatly. What’s more, the robustness of the proposed scheme is also proved by comparing the performance of the proposed scheme under different parameter settings.By predicting the potential requester’s willingness, the proposed user-information-aware D2D multicast file distribution mechanism pushes the video to potential requesters whose willingness greater than willingness threshold. The throughput and resource utilization efficiency are improved greatly by increasing the number of D2D multicast receivers. The utility values of all four schemes have studied in the above subsection, and the D2D transmission rate of all four schemes are studied in this subsection.The relationships between the D2D transmission rate and the number of service requesters Since the values of Based on the above experiments and analysis, the performance of the proposed mechanism has been fully verified. Owing to the advantages of large number of D2D multicast receiving users, the utility value of the proposed scheme has greatly improved. And compared with other schemes, even though changing the communication environments, the transmission rate is also better. The efficiency of spectrum and energy has improved dramatically. More importantly, the performance advantage can be more significant as the number of potential requesters increases.D2D communication, as a promising technology to solve the shortage of wireless spectrum resources, can provide more high-quality multimedia services for users. By D2D multicast file distribution technology, the redundant transmissions of multimedia files can be reduced, then dramatically improving the efficiency of spectrum and energy. So, substantial research effort has been undertaken to improve the performance of D2D multicast communication. However, the distribution of user’s service requests in the time domain is not fully considered in the existing design of D2D multicast communication system. There are a large number of users who have the same service demands with different service request times, which cause repeat transmission for same content, and the efficiency of spectrum and energy can be further improved. In this paper, the willingness of potential service requesters to accept the video push service is predicted firstly, and then the video is pushed to potential service requesters when distributing video for service requesters. The user-information-aware D2D multicast file distribution mechanism is proposed and the efficiency of spectrum and energy are improved dramatically by increasing the number of multicast receivers. To guarantee the QoE of potential service requesters, the users’ interests and status information of user’s device are fully taken into account in the calculation of the willingness of potential requesters. With the consideration of the social relationships and the channel quality information about users, the D2D multicast utility metric is proposed, and then a cluster head selection scheme is developed to maximize the utility value. The simulation results show that the file distribution mechanism proposed in this paper can greatly improve the system’s throughput, thus improving the efficiency of spectrum and energy, and the transmission rate also has an excellent performance.


As areas move closer to malaria elimination, a combination of limited resources and increasing heterogeneity in case distribution and transmission favour a shift to targeted reactive interventions. Reactive case detection (RCD), the following up of additional individuals surrounding an index case, has the potential to target transmission pockets and identify asymptomatic cases in them. Current RCD implementation strategies vary, and it is unclear which are most effective in achieving elimination.OpenMalaria, an established individual-based stochastic model, was used to simulate RCD in a Zambia-like setting. The capacity to follow up index cases, the search radius, the initial transmission and the case management coverage were varied. Suitable settings were identified and probabilities of elimination and time to elimination estimated. The value of routinely collected prevalence and incidence data for predicting the success of RCD was assessed.The results indicate that RCD with the aim of transmission interruption is only appropriate in settings where initial transmission is very low  1–2 or prevalence approx. < 7–19% depending on case management levels). Every index case needs to be followed up, up to a maximum case-incidence threshold which defines the suitability threshold of settings for elimination using RCD. Increasing the search radius around index cases is always beneficial.RCD is highly resource intensive, requiring testing and treating of 400–500 people every week for 5–10 years for a reasonable chance of elimination in a Zambia-like setting.The online version of this article (10.1186/s12936-019-2893-9) contains supplementary material, which is available to authorized users. One of the great challenges of malaria control in the face of decreasing transmission is onwards-transmission by asymptomatic infections , which aIn reactive strategies, when an index case of clinical malaria presents to a health facility, this triggers follow-up activities around the index case. Assuming that cases are geographically clustered and that presence or absence of symptoms is independent of surrounding cases, reactive interventions may thus allow targeted detection or intervention on symptomatic cases who do not seek care as well as asymptomatic cases. Although reactive strategies have high approval rates and have been implemented in a range of settings, in practice, many variations of strategies are employed globally. In low-prevalence urban areas of India, contacts of cases are screened . In SoutPrevious work using a deterministic susceptible-infected-susceptible (SIS) model highlights the importance of prevalence at the beginning of the intervention and suggests that relative values of the number of index cases followed, evalence . These mTwo large simulation experiments are reported in this paper. The first experiment is used to characterize settings where RCD alone can lead to interruption of transmission, assess which strategies are most efficacious in the different settings, and determine the sensitivity of success to programme specific parameters (follow-up capacity vs. search radius). The second experiment is used to assess the time to interruption of transmission and determine whether success is predictable through routinely collected data. Because the simulations are stochastic, the results were analysed using conventional statistical models and machine learning techniques, treating them as a large real-world experiment.https://github.com/SwissTPH/openmalaria.wiki.git), a modelling platform allowing for individual-based stochastic models of malaria dynamics in humans [Plasmodium falciparum dynamics in both humans and mosquitoes, allowing for simulations of interventions in comparatively realistic settings. Since blood stage parasite densities are tracked, the model allows for case management based on simulated events dependent on individual patient parasite densities. The simulated human population is updated every 5 days with multiple outcomes, including clinical incidence, the total number of infections, and the infectiousness to mosquitoes, which depends on the recent history of parasite densities. The original model required the fitting of 38 parameters of malaria epidemiology, either independently (13 parameters) for independent model components, such as within-host parasite dynamics, or through a combined fitting process (25 parameters). A total of 61 scenarios were constructed based on field data and correspond to field sites where the pattern of transmission and one or more epidemiological variables were known. Ten different objective functions (likelihood or sum of squares) were derived from these data sets, representing important epidemiological malaria relationships, such as age pattern of incidence of clinical malaria. A number of alternative model formulations exist.The impact of RCD was simulated using OpenMalaria . A warmRCD was modelled as a test-and-treat intervention added to and dependent on routine passive case detection and treatment included in the simulations for a period of ten years Fig. a. Withinof 0.942 , an addiOpenMalaria does not explicitly model the spatial pattern of infection. Instead, the effect of case clustering is captured by simulating treatment of all infections in eatments .The targeting ratio was estimated as a function of udy area , 17 and v. Coverage was calculated for each 1% prevalence interval and for This yields an intervention coverage Simulation experiment 1: a total of 83,200 simulations were run in a full factorial experiment, considering 64 settings defined by different transmission intensities and case management levels for different intensities of RCD with one random seed each (Table 14) was 21.8% with a failure probability of 19.3% [14 levels) were simulated. The simulated importation rate was zero.of 19.3% . This waof 19.3% ). Eight In each of the 64 settings, 1300 RCD strategies were considered  as a function of mentclass2pt{minimBecause of the stochasticity featured in the model, the simulated dataset was analysed as though it were a real-world experiment. The initial assessment was of whether and where RCD alone can lead to interruption of transmission as a proof of concept, considering also very low transmission settings . As transmission in such settings can be unstable, stochastic interruption of transmission may occur in control settings, so interruption of transmission in RCD simulations is not necessarily due to the RCD.Predictors of interrupting transmission: The proportion of simulations in Experiment 1 where transmission was interrupted was aggregated across all interventions with EIR as an independent variable, stratified by case management level. The number of simulations summarized per data point, n, was 1300 e is the number of scenarios where transmission was interrupted, Each of the 64 settings was further assigned to one of three categories depending on whether transmission was interrupted in all, none, or only some simulations. This indicated in which settings success was dependent on the RCD strategy. The proportions or probabilities of interrupting transmission for a given setting and RCD strategy were estimated using a range of classification algorithms ). This provided smooth probability surfaces in the absence of replication, thus avoiding the need for massive numbers of simulations. The performances of these algorithms were compared using 10-fold cross validated mean area under the curve (AUC) and accuracy estimates with a two-third training/test split.A formal variable importance analysis of the determinants of interruption of transmission was carried out by fitting a set of random forest classifiers to the simulation outcomes for settings where these outcomes were strategy-dependent. Two different random forest classifiers were used based on their inbuilt features, after finding their performance to be very similar (accuracy = 83–84%). The assessments considered the overall permutation importance of EIR, case management, A second approach measuring the overall incremental impact of RCD while adjusting for interruption of transmission in control simulations was to estimate the population attributable fraction, PAF. This is the proportion of simulations with interrupted transmission in Experiment 1 where transmission was interrupted because of the RCD, calculated as described in the supplementary information.Median time to zero prevalence in years: this was computed for each scenario in Experiment 2 where transmission was interrupted in simulations for at least 3 out of 5 random seeds.Prediction of RCD success: the simulations in Experiment 2 were also used to assess the suitability of routinely collected incidence and prevalence data in predicting RCD success (since EIR is not commonly measured in the field). Multiple single-variable logistic regressions was used to determine compare the following variables as predictors of RCD success: pre-intervention EIR, incidence and the prevalence in the year before introduction of RCD, in the first year of the intervention period, and the relative reductions of incidence and prevalence, defined as https://kogalur.github.io/randomForestSRC/). Calculations were performed at sciCORE (http://scicore.unibas.ch/) scientific computing core facility at University of Basel.The base model variant of OpenMalaria V36  was used14 = 46.1% and 49.8  at E14 = 13.9%. Overlapping confidence intervals and variability in PAF estimates yield no evidence of a trend for different case management levels. These results demonstrate that RCD can increase chances of interrupting transmission, but also highlight the stochasticity of this.Transmission was interrupted in 68.2% of simulations in Experiment 1, 69.3% of simulations with RCD and 42.7% of control settings. The proportion of simulations with interruption of transmission where this could be attributed to the RCD (PAF) was 37.5% overall . Results stratified by case management level are presented in Table Three example simulations of time series of malaria annual incidence per 10,000 person-years throughout the simulation period are presented in Fig. 0-99 values indicate mean prevalence prior to RCD.Figure 0-99 of 7–20%, depending on case management levels .For all settings where interruption of transmission is dependent on RCD strategy, strategy-dependent probabilities of interrupting transmission were predicted using Random Forest, SVM, Gaussian Process and Naïve Bayes Classifiers. Mean 15-fold cross-validated AUC was highest for Gaussian process classifier (range 0.70–0.98 across settings for 67% training), but predicted patterns were similar across all classifiers. The results are presented in Fig. To further assess the differential effects of setting specific parameters, an individual sensitivity analyses for EIR was carried out, stratified by case management level. Figure Figure Further analyses to determine characteristics of the The contributions of case management and case follow up to interrupting transmission were assessed. Figure These results demonstrate that Figure Since EIR is difficult to measure in the field, a range of possible predictors of routinely collected data was chosen to assess their predictive ability. The predictive powers of mean incidence and mean annual prevalence the year before onset of the intervention period and in the first year of the intervention period were tested. The predictive ability of the relative reduction in incidence and prevalence in the first year of RCD was also assessed. Prevalence values were log transformed for the purpose of this analysis. The results presented in Fig. A framework for implementing spatially targeted reactive interventions in OpenMalaria was developed by approximating a targeting ratio which captures spatial heterogeneity. Reactive case detection only leads to local interruption of malaria transmission in settings with low transmission potential, measured by either EIR or prevalence . RCD was effective in 38%  of scenarios simulated, with a small trend towards greater effectiveness at lower case management. Large and overlapping confidence intervals highlight the stochasticity of interrupting transmission. Whilst the simulations use transmission intensity in terms of EIR and 5-day case management levels as inputs, they show that qualifying settings are also identifiable using routinely collected prevalence and incidence data. It follows that settings can be classified into suitable or non-suitable for RCD, and predictions can be made such that RCD is not initiated where it is very unlikely to be successful. This is roughly consistent with another modelling study based on the same Zambian data, which suggests a prevalence threshold for RCD of approximately 10% . The relA primary objective of this study was to determine which operational characteristics of RCD most influence the effectiveness. Considering the joint and individual influences of increasing capacity to follow up index cases and the search radius, a larger search radius is always beneficial. In contrast, increasing ng ratio . The SISThis paper takes a slightly different programme planning focused approach by assessing the importance of the follow-up capacity rather than the actual number of followed up index cases. Cases that do not seek official care or are asymptomatic limit the potential number of index cases. When the case management level is increased, more index cases become available making it useful to adjust E14) at the time where the RCD trial was conducted was about 21.8% [14) is estimated to be 34.7%. Such a setting would require a follow-up capacity of approximately 10 index cases and search radius of > 35-40 individuals, i.e. a total screening capacity of 350-400 individuals per 5-day period would be necessary in order to reach interruption of transmission within 10 years with a probability of success of only 50%. On the contrary, if case management was further increased to E14 = 46% [Despite providing a proof of concept that RCD can lead to local elimination, the results also suggest that successful RCD is highly resource intense and likely to be very costly . In most suitable settings RCD would have to be conducted for more than 5 years with a relatively aggressive strategy to yield a probability of interruption of transmission of > 50%. In the area of the trial in Zambia, for example, the weighted mean EIR is estimated to be approximately 2.9  and the ut 21.8% . In such14 = 46%  suggestsdefinite cases that present to the health facility. All index cases are definitely cases (definite cases) whereas individuals in the search radius may or may not be cases at probability The results indicate that policy decisions should prioritize improving access to care followed by appropriate treatment and follow up of all index cases. This can be explained through a greater importance of following up as many as possible The results are based on Zambian parameterization and thus the transferability of results across settings with different population densities remains to be confirmed. However, by defining the search radius in terms of number of individuals rather than a physical distance, the findings presented here should be more translatable across settings at different population densities, assuming that vector movement and thus disease spread is dependent on host availability more so than physical distance. Future research comparing RCD in different settings should explore this hypothesis. The study did not consider case importation. Simulations of Zambian settings with low coverage of case management  concludeThe targeting ratio approach presented here provides a framework for implementing generic spatially targeted reactive interventions in OpenMalaria. Future work should adapt the framework to different settings by fitting the targeting ratio to data from different settings. However, as long as infections are acquired within the community similar patterns to those presented here can be anticipated, since the search radius is specified in terms of number of individuals, thereby making it independent of the population density. Future investigations may further include incorporating importation of cases as well as varying the timing of RCD and implementing RCD in combination with other (mass) interventions. If RCD is only successful at low transmission it would be well worth investigating adding a mass intervention at the beginning of RCD intervention course as well as employing RCD in scenarios where mass interventions have brought EIR down to < 3 infectious bites per person per year. Further, one may investigate employing RCD seasonally in the dry season when incidence is low. This may lead to stochastic elimination and save resources. This framework can also be adapted and used for wide ranges of spatially targeting interventions, such as RCD in different settings and reactive vector control.one-off higher impact interventions, such as MDA that have strong immediate effects over a limited period but do not provide a sustained reduction in transmission. With MDA, even in the most favourable circumstances, persistence is highly stochastic depending on the size of the residual reservoir of infectious people exposed to mosquitoes. However, despite its potential impact RCD is a highly resource intense, long-term intervention that is inappropriate in many settings where resources are limited. In such settings, investments may be better made in improving the routine health care system.Overall, the study demonstrates that RCD can increase the chances of stochastic elimination, but that it is a very resource intense, such that other interventions are likely more appropriate in most settings. In its final stages, RCD leads to a sustained reduction in overall burden of malaria through strengthening the health care system so that imported infections are controlled. This stabilizes the disease-free state , in contAdditional file 1. Additional figure.


It is thought that they supply about 25% of the energy for global ocean mixing through turbulence resulting from their strong current shear and breaking; this contributes mainly to upper-ocean mixing which is related to air-sea interaction, typhoon genesis, marine ecosystem, carbon cycle, and climate change. Observations and numerical simulations have shown that the low-mode NIWs can travel many hundreds of kilometres from a source region toward the equator because the lower inertial frequency at lower latitudes allows their free propagation. Here, using observations and a numerical simulation, we demonstrate poleward propagation of typhoon-induced NIWs by a western boundary current, the Kuroshio. Negative relative vorticity, meaning anticyclonic rotational tendency opposite to the Earth’s spin, existing along the right-hand side of the Kuroshio path, makes the local inertial frequency shift to a lower value, thereby trapping the waves. This negative vorticity region works like a waveguide for NIW propagation, and the strong Kuroshio current advects the waves poleward with a speed ~85% of the local current. This finding emphasizes that background currents such as the Kuroshio and the Gulf Stream play a significant role in redistribution of the NIW energy available for global ocean mixing.Near-inertial waves (NIWs), which have clockwise (anticlockwise) rotational motion in the Northern (Southern) Hemisphere, exist everywhere in the ocean except at the equator; their frequencies are largely determined by the local inertial frequency,  The ocean needs about 2.1 terawatt of energy for mixing, and NIWs are responsible for 0.4–0.7 terawatt4, approximately 25% of the total. NIWs exist everywhere in the ocean (except at the equator) from tropical to polar regions5. They redistribute energy through long-distance propagation in stratified waters and are dissipated eventually through turbulence due to their high shear3. Nevertheless, because of low spatial resolution (>1/4 degree) and low temporal resolution of the wind forcing (>6 hours), climate and Earth system models which are used for future climate prediction do not represent realistic NIWs and their mixing8.Ocean mixing, mainly driven by wind and tides, is known to play a crucial role in maintaining oceanic stratification and the global-scale thermohaline circulation11. Negative relative vorticity induced by horizontal current shear can trap and amplify NIWs12 with enhancement of NIW energy transfer to the deep ocean15. Numerical simulation and observations have shown that the Gulf Stream and Kuroshio, the western boundary currents in the Atlantic and Pacific Oceans, can move the waves eastward away from their sources, and hence produce a NIW “desert” south of a western boundary current17. Nevertheless, our understanding of the behaviour of non-equatorward NIW propagation is insufficient, largely due to lack of observations, especially in strong current regions.NIWs travel over hundreds of kilometres toward the equator because of decreasing inertial frequency with latitude18 and more favourable wind-direction change. The Joint Kuroshio-Ryukyu Current System Study (JKRYCSS), an international collaborative project to observe the Kuroshio and Ryukyu Current systems, began in June 2015, and tall current moorings were installed in the Okinawa Trough to monitor the Kuroshio where it flows northeastward. While the current moorings were in operation, four typhoons passed over or near the two mooring sites: CHAN-HOM in July, SOUDELOR in early August, GONI in late August, and DUJUAN in late September  at all measurement depths, 64–448 m, during both typhoon passages  at KCM 1, but, with this so-called red-shift, the period of NIWs determined from the spectral analysis was 30.3 hours (=0.033 cph) (see Methods), corresponding to ~0.9 f.The strongest observed NIW events were responses to the two typhoons SOUDELOR and DUJUAN, which crossed the Kuroshio upstream, east of Taiwan, about 350 km southwest of the mooring sites on August 8ely Fig. ; these eely Fig. . Energetion Fig. . For DUJion Fig. . The wavges Fig. . The loc−1) at the mooring sites at 00 h GMT on August 8th when the most intense NIWs are generated by typhoon SOUDELOR, and the waves in the Kuroshio downstream and on the northern side of the mooring sites are weaker still  at the mooring sites, while strong (>0.4 m s−1) in the Kuroshio upstream, roughly 2 times farther from observation sites than during typhoon SOUDELOR  around the mooring sites when SOUDELOR and DUJUAN go through, however they become strong 1–2 days and 2–3 days later at the sea surface , is longer than 30 hours  along the right-hand side of the Kuroshio up to about 27.5°N  region with 80–90 km width on the right-hand side of the Kuroshio path during the passage of SOUDELOR and of DUJUAN Fig. . Due to 5°N Fig. . This imeff Fig. . In othe−1  m day−1, the NIWs at 100-m depth can have different phase at a fixed time  and KCM2 near its edge. The two stations were separated by about 34 km distance  at about 500-m depth, and single-level-measuring current metres at 1000-m and 1500-m depths with sampling interval of 30 minutes. The uncertainty of the 30-minute-interval ADCP data in configuration of 16-m bin size and 10 pings ensemble from Workhorse Long Ranger 75-kHz ADCP (20° beam angle) is 1.23 cm snce Fig. . Ocean dhttps://dreams-c.riam.kyushu-u.ac.jp/vwp/]23. This system has horizontal resolutions of 1/12° in longitude and 1/15° in latitude, based on the RIAM Ocean Model (RIAMOM)24, a free-surface primitive general circulation model developed by the Research Institute for Applied Mechanics (RIAM) of Kyushu University. It is a three-dimensional, 38-layer, z-coordinate model that assumes hydrostatic balance and Boussinesq approximation. 32 of these 38 layers covers from the surface to 2250 m. The model includes tides25 and ocean general circulation and is forced by 6-hourly atmospheric forcings  with 3rd-order Lagrange polynomial interpolation. Sea surface temperature data (MGDSST) of the Japan Meteorological Agency were utilized for the surface relaxation with a time scale of 3 days, and the along-track AVISO sea surface height data were assimilated by a reduced-order Kalman filter.Data-assimilative three-dimensional high-resolution numerical ocean model outputs (hourly) from the real-time forecast system covering the East Asian marginal seas were analyzed [t is time, z is the vertical Cartesian coordinate (positive upward), ρ is water density, T ( = 20 days) is an averaging period, and 28. This filter was a third-order Butterworth phase-preserving band-pass filter applied with cutoffs at −2 and +10 hours from the local inertial period. These cutoff periods, based on rotary spectral analysis, were chosen to prevent diurnal tide (D1) interference and took into consideration frequency shifts of the NIWs  ζ denotes anticyclonic (cyclonic) circulation.The effective Coriolis frequency is given by Supplementary Video 1 SOUDELOR_NIW_Hori_4mSupplementary Video 2 SOUDELOR_NIW_Hori_100mSupplementary Video 3 DUJUAN_NIW_Hori_4mSupplementary Video 4 DUJUAN_NIW_Hori_100mSupplementary Video 5 SOUDELOR_Along_Kuro_100mSupplementary Video 6 DUJUAN_Along_Kuro_100mSupplementary Video 7 CHANHOM_NIW_Hori_4mSupplementary Video 8 CHANHOM_NIW_Hori_100mSupplementary Video 9 GONI_NIW_Hori_4mSupplementary Video 10 GONI_NIW_Hori_100mSUPPLEMENTARY INFO


Restoration of agricultural fields is challenging, especially in arid and semi-arid ecosystems. We conducted experiments in two fields in the Great Basin, USA, which differed in cultivation history and fertility. We tested the effects of different levels of functional diversity , seed source , and irrigation regime  on restoration outcomes. We sowed either: 1) grasses and shrubs in year one, 2) shrubs only, in year one, 3) grasses in year one with herbicide, shrubs in year two, or 4) shrubs alone in year two, after a year of herbicide. We irrigated for two years and monitored for three years. Shrub emergence was highest in the lower fertility field, where increasing functional diversity by seeding grasses had a neutral or facilitative effect on shrub emergence. In the higher fertility field, increasing functional diversity appeared to have a neutral to competitive effect. After declines in shrub densities after irrigation ceased, these effects did not persist. Grasses initially suppressed or had a neutral effect on weeds relative to an unseeded control, but had neutral or facilitative effects on weeds relative to shrub-only seeding. Initially, commercial grasses were either equivalent to or outperformed wild-collected grasses, but after irrigation ceased, commercial grasses were outperformed by wild-collected grasses in the higher fertility field. Local shrubs initially outperformed distant shrubs, but this effect did not persist. Fall and spring irrigation combined with local shrubs and wild-collected grasses was the most successful strategy in the higher fertility field, while in the lower fertility field, irrigation timing had fewer effects. Superior shrub emergence and higher grass persistence indicated that the use of wild and local seed sources is generally warranted, whereas the effects of functional diversity and irrigation regime were context-dependent. A bet-hedging approach that uses a variety of strategies may maximize the chances of restoration success. Abandonment of agricultural practices in dryland ecosystems is becoming increasingly common worldwide –3. For esensu [Another factor that can improve restoration outcomes in arid and semiarid ecosystems  is the use of seeds that are adapted to site conditions . The rolsensu ). Thus, sensu .Plant-plant interactions, both competitive and facilitative, can also play a large role in restoration outcomes . In wateThe stress-gradient hypothesis predicts that plant facilitation is more likely to occur in more stressful environments , and expHere, we seek to improve our understanding of treatments that can increase restoration success in dryland old-field environments, and improve upon the results of our last experiment. First, we ask how functional diversity affects restoration outcomes, specifically asking whether seeded grasses can suppress weeds and facilitate shrubs during restoration. To promote facilitation, we reduced the total water addition and seeding rates from those used in a previous study , with thDoes seeding both grasses and shrubs result in lower weed abundance or weed height?Do results depend on seed origins?1) Does functional diversity help or hinder shrub emergence and establishment?We investigate these questions under two scenarios: (1) shrubs and grasses seeded together in the first year, and (2) shrubs seeded in the second year, one year after grass seeding and weed control, comparing both of these scenarios to shrub-only seedings. We expected greater weed suppression under the grass seeding treatments, and expected these grass seedings to facilitate shrub establishment.2) Does seed source affect restoration outcomes?We compared emergence and establishment of commercially-sourced vs. wild-collected perennial grasses, and wild-collected shrubs originating from either more local or distant seed sources, and we also asked how seed source affected weed abundance. Simultaneous manipulation allowed us to ask if there were potential interactions among seed sources of these two functional groups. Because of agricultural legacy effects in these old-fields, we expected commercially-sourced grass cultivars to perform well during irrigation treatments, but for their performance to decline after irrigation ceased. We expected more locally-collected shrubs to outperform more distant collections. Because of the potential for commercially-available grasses to grow large quickly, we expected greater weed suppression from these sources, but for similar reasons, lower shrub survival, especially for non-local shrubs.3) How does resource availability affect restoration outcomes?We tested this question by comparing plant abundance under two different irrigation regimes , and by conducting our experiments in two restoration sites that differ in soil fertility due to differences in agricultural histories. We expected fall and spring irrigation treatments to outperform spring-only irrigation, as many of the native species in this region can germinate in the fall, or require a cold/wet seed stratification for germination. Further, we expected greater restoration success in our lower-fertility field site, due to reduced weed competition, and expected that seed sources would have strong, but possibly opposite, impacts on restoration outcomes in our two sites.Through these questions, we aimed to identify restoration treatments that result in the highest densities of grass and shrub establishment, and identify a strategy that was effective in old field sites with different land use history. For all questions, we present our results for two restoration stages: (1) plant emergence and early seedling development over the first two years after seeding (2015–2016), and (2) plant survival and establishment during the third year of the study (2017), after irrigation treatments ceased.Medicago sativa L. . These sites differ in their recent history of cultivation, and represent the two main types of old fields requiring restoration in this region: fields transitioning directly from production to restoration (North Field), or abandoned fields needing active restoration to return native shrub communities (South Field). The North Field was under alfalfa production for a decade or more until the summer of 2013, while the South Field had not been in production for at least a decade. Prior to the start of the experiment, the North Field contained abundant residual alfalfa plants, while the South Field contained sparse alfalfa plants, and common agricultural weeds were present at both sites  and the “South Field”  were historically leveled, tilled, and cultivated for the production of th sites . Both sihttp://prism.oregonstate.edu, accessed 15 Oct. 2016). Over the experimental period, total precipitation was 174 (97%), 223 (125%), and 234 mm (131% of average) during the 2014, 2015, and 2016 water years (Oct. 1 –Sept. 30), respectively ). The North Field soil is somewhat finer textured than the South Field soil, and consistent with textural differences and more recent alfalfa production, it is a more fertile site, especially in terms of N availability (Sarcobatus vermiculatus (Hook.) Torr. (black greasewood), Atriplex confertifolia (Torr. & Frém.) S. Watson , Atriplex canescens (Pursh) Nutt. , Atriplex torreyi (S. Watson) S. Watson , Artemisia tridentata Nutt. (big sagebrush), Picrothamnus desertorum Nutt. (bud sagebrush), and Ericameria nauseosa  G.L. Nesom & Baird (rubber rabbitbrush).Historic annual precipitation at the sites averaged 179 mm (7.04 in) for the period of 1980–2010  in a split-split plot randomized complete block experimental design. We used five seeding strategies  to examiWe manipulated the amount and timing of irrigation in two irrigation treatments: (1) spring irrigation only , and (2) fall plus spring irrigation . Irrigation was adjusted according to ambient rainfall and capped at a maximum of 229 mm (9 in) of total annual water addition, with the goal of not overly stimulating weed productivity, based on results from previous work . SimilarArtemisia tridentata ssp. wyomingensis (Wyoming big sagebrush), Atriplex canescens , Ericameria nauseosa (rubber rabbitbrush), Sarcobatus vermiculatus (black greasewood), and Atriplex torreyi . Grass species were Achnatherum hymenoides (Roem. & Schult.) Barkworth (Indian ricegrass), Sporobolus airoides (Torr.) Torr. , Elymus elymoides (Raf.) Swezey (bottlebrush squirreltail), and Leymus cinereus (Scribn. & Merr.) Á. Löve (basin wildrye). With the exception of S. airoides, for which a wild-collection was not available, two sources of seed were obtained for each grass species: a wild-collected source originating from collections as near the planting sites as possible (“wild-collected”), and a commercial source representing commercially-available seeds originating from non-local locations . Because of the single seed source, Sporobolus airoides results were removed from analyses of seed origin. Seed sources for shrubs were all wild-collected, as these species are not typically farmed and there are few to no native shrub cultivars developed. Shrubs were sourced from multiple locations, either more distant from the site  or more local to the site . All seed was purchased from Comstock Seed  and mechanical treatments  to remove existing weeds and alfalfa. Seedbed preparation consisted of rototilling to a depth of 10 cm followed immediately by a ring roller cultipacker to firm the soil. First year seeding occurred Oct. 7–10, 2014, and second year seeding between Sept. 29-Oct. 1, 2015. Seeds were sown at a depth of 1.3 cm, within the range of recommended rates –44 S3 A, using aWe used chemical and mechanical treatments to reduce weed densities . In the Irrigation was applied using sprinklers mounted on 0.9 m risers, with a distance of 9.1 m between sprinkler heads. In the first year, the Fall+Spring irrigation treatment plots received 51 mm in the fall (2014) and 102 mm in the spring (2015), while the Spring plots received the spring irrigation only  . In spriWe monitored densities of seeded grasses in December 2014 (no shrubs emerged at this time), and seeded species and weeds in May 2016 and May 2017, either one month (May 2016) or 13 months (May 2017) after the last irrigation event. At all sampling dates, emergent shrubs were monitored by species; grasses were not identified by species until 2017. Grasses and shrubs were assessed in 1 x 1 m quadrats, while weeds were assessed in a randomly selected 25 x 25 cm corner of the quadrat. In cases of very high weed densities, we used a reduced 10 x 10 cm sampling size to improve accuracy of counts. In December 2014, we monitored seeded grasses in three quadrats at random locations in each subplot in each field. In 2016, we randomly placed three quadrats in each of the five monospecific shrub strips in each subplot in the South field, and at least one quadrat per shrub strip in the North field; sampling intensity differed between the two sites due to very low seeding establishment in the North field and limitations to field crew time. Due to the very high weed presence in 2016, we measured maximum height of weeds. In 2017, three quadrats per strip were sampled in both the North and South Fields, and we included a full census of all shrubs present in each subplot in 2017, in addition to counts in quadrats. For all dates, we scaled density counts up to 1 x 1 m, if necessary, and averaged values across quadrats by subplot prior to analysis.P<0.06) are also discussed. Analyses were performed separately for the South Field and North Field, after initial analysis indicated strong differences between sites. Similarly, sampling date was initially included as a main model factor, but because it showed consistently significant interactions with other factors, we analyzed results separately for each sampling date. All models were built from some or all of the following fixed factors and their interactions: irrigation treatment, seeding strategy, shrub origin, and grass origin. When shrub origin was included in the model, analyses were limited to seeding strategies I-IV; when grass origin was included, analyses were limited to seeding strategies I-II. To test the interaction between grass seed origin and shrub seed origin on restoration outcomes, we ran a model with all four factors  and their interactions. To control for the spatial patterns of variation potentially associated with our experimental design, three random effects were also included in the model structure: block, sub-block (nested within block), and plot . We were unable to model individual shrub and grass species responses due to uneven emergence or establishment of some species in certain treatments, which resulted in many zero counts and non-normal residuals. Thus, models were constructed with functional group response variables , but we present species-level data in figures and tables for shrubs in both years and for grasses in 2017. Exact model structures are specified for shrub and grass density, and weed height and density in model results tables . Significance level was set at α = 0.05, and results with borderline significance  and distant shrubs (P = 0.9) , but there was no effect of seeding grasses on local shrub density (P = 0.9) , or negatively affected by competition with grasses when seeded in year 2 (strategy I vs. IV) for the Fall+Spring irrigation treatment . SeedingP = 0.02 in the South Field and P<0.001 in the North Field; Table A in P = 0.7) and North Field (P = 0.8)). However, when shrubs were seeded a year after grasses and herbicide use (strategy I), the presence of grasses facilitated weeds (comparison of strategy I vs. IV in the South Field (P = 0.02) and North Field (P = 0.007)). Although weed densities were facilitated by grasses when shrubs were seeded a year after grasses , weed density in this strategy was reduced relative to the control treatment (strategy V) in the North Field (P<0.001), and was not significantly different from the control in the South Field (P = 0.5). In both the South and North Fields, weed density was also reduced in strategy IV (herbicide followed by shrubs in year two) relative to the control treatment . The control treatment (strategy V) did not differ significantly from strategies II (P = 0.9 and P = 0.5) or III (P = 0.7 and P = 0.4) in the South and North Fields, respectively. Weed densities were not influenced by grass or shrub seed sources, nor were densities impacted by irrigation treatment; we initially included these factors in our analysis, but they were consistently insignificant and resulted in poor model fit.At both sites, weeds were very dense in 2016  but not the South Field  and after grasses . Weed height in the control treatment (strategy V) was significantly lower than when shrubs were seeded in year two , but did not differ from the other strategies. In the South Field, none of our experimental factors had an effect on weed height  due to very little variation in the maximum height of weeds across all treatments.In 2016, weed height was significantly influenced by grass seeding in the North Field  were unseeded volunteers growing outside their own seeded strips  and early establishment (2017). In the South Field in 2016, the effect of shrub seed source was dependent on seeding strategy , while shrub density was not affected by grass origin in the Spring irrigation treatment (P = 0.8)  .P = 0.9; P = 0.01; ; P = 0.3; P = 0.04; Performance of grasses also differed by seed source and shifted from the seedling stage (2016) to early establishment (2017). In 2016, there were interactions between grass origin and irrigation treatment in both the South and North Fields, and an interaction between grass origin and seeding strategy in the North Fields . In the P<0.001, A. hymenoides, which was the most successful species of the three locally-sourced grasses.By 2017, any advantages that commercial grasses had over wild-collected grasses in 2016 were lost or reversed Figs . In the P = 0.006; P<0.001; P = 0.7; In the South Field, though grasses of different origins were not different, overall grass density varied with shrub origin and irrigation  interaction at the South Field  nearing those of surrounding natural areas  by the end of our study. We also had greater plant overall plant emergence and establishment in our lower-fertility field, relative to the more recently cultivated, higher-fertility field, indicating that a period of fallow between active cultivation and restoration attempts may be valuable in similar systems. Seed source is an important factor known to affect restoration outcomes [Some land use changes are very challenging to reverse, and ecological resilience, or the propensity of vegetation to return to a previous state after intervention, can be a negative ecosystem property if change is desired, as is the case in restoration ,46. Agrioutcomes ,48,49, aIncreasingly, the theory of plant facilitation is frequently incorporated into restoration practice , yet facOur study design also allowed us to test potential interactive effects of shrub and grass seed sources in the context of restoration, but we observed no significant interactions between seed sources of the two plant functional types for density responses in any site or in any year. Additionally, grass seed origin itself also did not affect the direction of the interaction between grasses and shrubs, which is surprising given that many of the traits for which grass cultivars are bred could make them highly competitive . HoweverEmergence is a critical life stage, one that is often a significant population bottleneck in arid and semiarid ecosystems ,56. TherIn general, weeds are a significant barrier to native re-establishment during restoration , and dry-2 after two years of irrigation); our effort to reduce competitive effects and increase facilitative ones was successful. Reduction of weed density was consistently observed in treatments where herbicide was applied without grass seeding, and in our higher fertility site, the presence of grasses further reduced weed height, and this was the case whether herbicide was applied or not. Our findings suggest that the seeding of grasses can be compatible with shrub emergence during restoration in these ecosystems, and that there may be weed-suppressive benefits of perennial grasses in higher-fertility old fields.We hoped to use perennial grass seeding as a method for reducing weed pressure. Achieving grass densities that allow for shrub establishment while also resulting in weed suppression is a delicate balancing act, influenced by restoration treatments, such as grass seeding rates, irrigation, and species identity ,27,62, aA. hymenoides, a native grass common in the arid and semiarid western USA and found across a range of soil conditions [We included multiple species in our seeding mix, in addition to multiple seed sources, and there were several cases where species-specific responses appeared to be responsible for positive restoration outcomes in particular treatments. This is consistent with ideas about links between biodiversity and stabilizing community-level processes, such as the portfolio effect or statistical averaging effect ,64, whicnditions , was preE. nauseosa shrubs, which accounted for 76% of the established shrubs in the South Field, including in the unseeded, no herbicide control treatment Click here for additional data file.S2 Appendix(PDF)Click here for additional data file.S3 Appendix(PDF)Click here for additional data file.S4 Appendix(PDF)Click here for additional data file.S5 Appendix(PDF)Click here for additional data file.S6 Appendix(PDF)Click here for additional data file.


We found evidence for an increase in both expression and activity of STS in response to a decidualisation stimulus with abrogation of oestrone biosynthesis and decreased secretion of the decidualisation marker IGFBP1 in the presence of STX64. These results provide novel insight into the contribution of STS to the intracrine regulation of decidualisation.In women, establishment of pregnancy is dependent upon ‘fine-tuning’ of the endometrial microenvironment, which is mediated by terminal differentiation  of endometrial stromal fibroblasts (ESFs). We have demonstrated that intracrine steroid metabolism plays a key role in regulating decidualisation and is essential for time-dependent expression of key factors required for endometrial receptivity. The primary aim of the current study was to determine whether sulphated steroids can act as precursors to bioactive sex steroids during decidualisation. We used primary human ESF and a robust  Our results provide new insight into the mechanisms that contribute to generation of an oestrogen-rich microenvironment during the establishment of pregnancy.In the current study, we sought to complement and extend our previous investigations by assessing the contribution of STS to intracrine regulation of decidualisation. We used an n = 9) was obtained from women undergoing surgery for non-malignant gynaecological conditions. None of the women were receiving hormonal therapy or suffering from endometriosis. Primary hESFs were isolated from proliferative phase endometrium and cycle phase determined as reported previously . Decidualisation was induced by addition of decidualisation (DEC) media , 1 µM progesterone ). Some cell cultures were supplemented with the STS inhibitor Irosustat  for the duration of the culture period. Control cultures were incubated with phenol red-free RPMI 1640, 2% CSFCS and equivalent volume of vehicle control (DMSO). 2 × 105 hESFs were seeded per well of six-well plate, treatments were in duplicate and assessed in minimum of three individual patients for all treatments. For experiments assessing expression and activity of sulphation enzymes/transporters, cells from n = 6 patients were assessed. For experiments assessing the impact of STX64, cells from n = 3 patients were used. Each sample was assayed in duplicate and average values were analysed. To assess the time-dependent accumulation of secreted products, treatments were maintained for the duration of each time point. hESFs were treated for 24 h (1 day), 48 h (2 days), 4 days or 8 days as indicated; cells were treated in parallel with dedicated samples for each time point and patient. The expression of genes associated with sulphation, desulphation and transport of sulphated steroids was assessed by RT-qPCR.Primary human endometrial tissue  as an internal control. Primers/probes are given in Supplementary Table 1 .Insulin-like growth factor-binding protein 1 (IGFBP1), E1 and E2 in culture supernatants were determined by ELISA as described previously a. E1 an3H] E1S (4 × 105 dpm) adjusted to a final concentration of 20 μM with unlabelled E1S. [4-14C] E1 (1 × 104 dpm) was used to monitor procedural losses. E1 was separated from E1S by toluene partition and 3H and 14C radioactivity was measured by liquid scintillation spectrometry. Results were expressed as E1 formed pmol/h/mg protein.STS activity was determined in cell lysates as described previously . Methods were carried out in accordance with NHS Lothian Tissue Governance guidelines. Studies using these cells have previously been reported in (STS as well as members of the sulphotransferase gene family in cells recovered 1–8 days after incubation with control (VC) or DEC culture media , 2  and 4 . To complement these findings, STS activity was assessed in cell lysates and was significantly increased in lysates from hESF treated with DEC media compared to VC after 4 days of treatment .We assessed expression of re media  and 2. ESULT1E1 and SULT2A1 mRNAs were not detected (not shown). In contrast, mRNAs encoded by SULT1A1 and SULT2B1a were present , 2  and 8 days  of culture. SULT2B1a mRNAs were significantly increased on days 1  and 2  of culture, however, by day 8, this was reversed with a significant decrease detected in DEC compared to VC-treated hESF .To determine whether E1 and E2 formed by decidual cells  and 8 , whereas PAPSS2 mRNA concentrations were only higher on day 1  and unchanged at other time points , 2  and 4  days, with the greatest increase in expression detected after 8 days . In contrast, ABCC4 mRNA expression was significantly decreased in hESF treated with DEC compared to controls at 2 , 4  and 8  days , which mediate influx of sulphated steroids were not detected in either control or decidualised hESF (not shown).We assessed expression of cellular transporters ABCC1 and ABCC4, which are associated with efflux of sulphated steroids. Expression of mRNAs encoding sed hESF . ABCC1 m01) days . Express1S or E2S in conditioned media from hESF, however, neither steroid was detected in either the control or DEC samples .In light of these results and as a complement to our previous studies in which we demonstrated that both E1 and E2 are secreted into culture media during our decidualisation protocol  but at later time points, there was no significant difference between hESF treated with DEC and DEC STX. In contrast to E1, concentrations of secreted E2 were not altered between hESF treated with either DEC alone or DEC STX . We next assessed if altered bioavailability of oestrogens affected decidualisation of hESF. Notably, STX64 altered secretion of the decidualisation marker IGFBP1; with concentrations reduced at each time point and significantly decreased after 1 day in hESF treated with DEC STX compared to DEC alone .We investigated the potential importance of STS activity during decidualisation of hESF by assessing the impact of the selective, irreversible STS inhibitor Irosustat (STX64). hESFs were stimulated with DEC media or co-incubated with STX64 (DEC STX) for 1, 2, 4 or 8 days. Incubation with STX64 was associated with altered production of oestrogens from hESF and mean concentrations of secreted E1 were decreased at each time point in hESF treated with DEC STX compared to DEC alone . The impde novo synthesis, which requires aromatase, and activation of circulating sulphated steroids which requires STS  had a time-dependent impact on decidualisation and decreased secretion of IGFBP1 from days 1 to 4 of the time course. Decreased secretion of IGFBP1 was associated with concomitant decreases in E1 concentrations suggesting STS-dependent regulation of intracrine oestrogens occurs during decidualisation. Notably, the aromatase inhibitor letrozole is reported to completely inhibit uterine oestrogen production in ovariectomised mice  encoding SLCO1A2, SLCO1B1 and SLCO2B1 as well as ABCC1 and ABCC4 were reported in uterine samples; although expression of SLC isoforms was relatively low compared to other tissues ; MRC grant MR/J003611/1 (to H O D C).Experimental design: D A G, P T K S, experimental procedures: D A G, P A F, I S, F C, O K, manuscript preparation: D A G, I S, P T K S.