Artificial reefs (ARs) are one of the most popular means of supporting marine ecosystem conservation and coastal fisheries, particularly in developing countries. However, ARs generate complex socio-bio-economic interactions that require careful evaluation. This is particularly the case for ARs outside no-take zones, where fish might be subject to enhanced exploitation due to easier catchability. Here, we conducted an interdisciplinary study on how ARs impact fish and fishing yields, combining mathematical and sociological approaches. Both approaches converge to confirm that fishery yields decline when ARs are exploited as if they were open access areas. This situation typically occurs in areas with weak governance and/or high levels of illegal fishing activity, both of which are common in many developing countries. To avoid these adverse effects and their associated ecological consequences, we recommend prioritizing the onset of a long-term surveillance system against illegal fishing activities, and adapting design and location of the ARs based on both and local and academic knowledge, before the deployment of ARs. Artificial reefs (ARs), or human–made reefs2, have been widely advocated by governmental and non-governmental conservation and management organizations for addressing these issues. Industries, particularly oil and gas, seeking to avoid the costs of removal or conventional disposal of used materials are often major advocates for deploying ARs. Yet, major questions remain regarding the success of such efforts in the context of weak governance and poorly sustained international investment in AR development projects. There is frequently confusion over whether or not ARs should be fishing sites and the precise goals of constructing such ARs are often unclear, making difficult to evaluate their successfulness3. Over the last 40 years, both failures and success AR implementation programs have been reported5. The main point of the present work is to underline the importance of the governance issue and address social and management factors on AR “success”.Coastal artisanal fisheries, particularly those in developing countries, are facing a global crisis of overexploitatione.g.,2). Yet, most ARs were historically delineated as sites for fishing4, and were rarely implemented at large scales in/for no-take zones, even in countries with centuries of experience in constructing ARs, such as Japan. In Japan, fishery authorities and local fishers use ARs to promote sustainable catches and to establish nursery grounds of target species6. However, fishery authorities and local fishery cooperatives in Japan have extensive management authority over ARs. For example, fishing around ARs is usually limited to hook and line techniques, with net fishing rarely being permitted in areas where risk of entanglement in ARs is high. Furthermore, during spawning, fishing gear and fishing season are often restricted around ARs in Japan. These practices are recognized for their effectiveness in maintaining good fishing performance and marine conservation in Japan and elsewhere where they have been implemented7.To improve fishery yields, it has been recommended that ARs must be no-take areas  and the area covered by these structures was about 550 m2. Simultaneously, a local management committee, constitute by small-scale fishers, was set up with the support of JICA and has endeavored to manage the area around the ARs. Subsequently, underwater monitoring was carried out for two years and the effect of fish attraction around the AR was quantified16, confirming the testimony of local fishers. Since then, several research and management projects focused on this AR provided detailed biological and socio-economic data in the years following its immersion17, but no systematic or quantitative survey has been conducted so far. However, after the project ended, which funded the monitoring and surveillance, because the AR attracted both fish and fishers, local overfishing and fisher conflicts were reported.The case study was a pilot project initiated by the Japanese International Cooperation Agency ‘JICA’ in 2004In this context, we specifically sought answers on whether current AR projects in developing countries sufficiently address the social and governance framework. Based on results, we propose some general recommendation necessary for ARs projects in developing countries to be useful and effective for fishery management and conservation.3, Fig. The model showed that, in the absence of illegal fishing, there was an optimum volume of ARs to maximize catch in ARs with both production and attraction effects , all levels of illegal fishing would cause total catch to decline, and catch became larger on the AR than in surrounding open access fishing areas if illegal fishing exceeded 6% , and most of the catch was derived from the fishing area . Respondents stated that overfishing was mainly caused by both local and illegal industrial fishing boats (70%) operating  in coastal areas, and to a lesser extent to artisanal fisheries (30%). This answer could be naturally biased by the fact that respondents were artisanal fishers. Habitat destruction was cited by 21% of respondents, who mainly mentioned industrial bottom trawling as being responsible. None mentioned climate change as a reason for fish declines. However, 61% of fishers suggested other reasons for fishery declines, including the use of specific fishing gear (mainly monofilament purse seine nets) and fishing activities targeting juvenile fish. Overall, 72% were in favor of fisheries management rules being implemented, 63% were in favor of the concept of no-take areas, and 92% were in favor of limits to catch volume. However, only 39% would accept rules limiting the size of fish captured. At the local scale, 81% of respondents perceived an increase in biomass in the AR directly after its deployment, 14% stated that biomass was stable or did not know, and 4% stated that biomass had decreased. Overall, 46% of respondents thought fish were attracted to the AR , 53% thought that fish find the AR by chance, and only one fisher had no opinion. To the question “to who belong the fish on the AR?”, all fishers (100%) answered “to all Senegalese fishers,” in preference to all other possible answers, which were local fishers or the state. Fishers did not provide information about the location of their fishing sites, except that their offshore limit was 3 to 10 km. Fishers did not clearly answer the question about the presence of migrant fishers, with some explaining that Yenne fishers were, themselves, migrants. Many targeted fish species were cited, including predatory and prey pelagic and demersal fish species, plus lobsters, sharks, cuttlefish, and octopuses. To the question of which community was fishing on the AR, only 4 (5%) fishers stated that no one was fishing there. All other interviewed fishers (95%) stated neighboring communities or that, in absence of surveillance, all fishers from Yenne were fishing on it. Respondents were not comfortable with the question about the existence of conflicts. Only 14% stated the existence of conflict over AR usage, mainly between line and net fishers and with neighboring communities. However, impressive stories of open conflicts around the AR involving numerous fishers were reported once the questionnaire was finished.Most fishers (80%) considered that the AR was actually an open access fishing area, contrary to the official position of the national authority and local managers. However, the same fishers considered that the AR could only be useful to them if fishing was banned on it. Fishers who advocated the banning of fishing activities on the AR had an empirical understanding of fish population dynamics, which allowed them to anticipate the beneficial effects of this practice. Their opinion, expressed in their answers to the open questions, was based on empirical knowledge that fish concentration on the AR might favor either their reproduction and/or growth if protected from local high fishing pressure. The latter also caused a feeling of inequity among fishers, depending on their ease of access to the AR for fishing.To further investigate the contrasting perceptions of fishers and how the AR was actually used, we clustered the surveyed fishers by age. The older group, named “experienced fishers” (older than 45), were more involved in co-management Fig. . This ini.e., introducing fishing rights. However, after discussions with Senegalese stakeholders, it was decided that no-take areas would be delineated around ARs because the establishment of a strong fishing rights regime was not socially acceptable to the Senegalese fishing community. Japanese governance is based on the acceptance and respect of fishers towards individual, private AR concessions. In contrast, fishers in Senegal, and more widely in West Africa, are characterized by high mobility, particularly in the context of climate change and overexploitation19. Consequently, respect for local management regulations is lower, with open access being generally assumed. The basic concept of implementing a no-take area on the AR was not easily accepted by fishers. The immersion of AR concrete blocks was set as a top priority by managers at the expense of more complex socio-economic considerations, such as consciousness-raising activities and self-sustaining participative monitoring of the AR.When introducing ARs as a fisheries management tool to Senegal, the Japanese management had the mindset of Japanese stakeholders, 11, as was true for our study16. Though the AR volume was relatively small (70 m3), the empty space between the higher blocks also contributes approximately 280 to 570 m3 of good habitat/refuge for schooling fish; therefore, it is actually difficult to accurately describe the volume that affects fish. Thus, it is difficult to say whether this AR is below or above the forecasted optimal volume in absence of fishing (120m3 with model parameters). The existence of an optimal volume for AR was also suggested by field studies as a trade off between food supply and refuge20, in line with our results. For management purposes, it is interesting to determine whether the AR is above or below this optimal level because if the volume is too small, the model predicted that any level of fishing on the AR would, in the long term, decrease the catch in the considered area. On the other hand, if the volume is above the optimal level, a small fishing effort on the AR could be authorized and would increase the total catch in the area.The clear contradiction between the ecological knowledge of fishers and their behavior was explained by the well-known effects of open access resources on individual behavior. This phenomenon was also observed in our mathematical model. The processes in the mathematical model are in accordance with those perceived by the fishers, so that the results are also those expected by fisher’s local ecological knowledge. It is interesting to notice that the theoretical results presented here are the mathematical solutions of the model at equilibrium between fishing effort and fish population growth, i.e. after an oscillation period. It is obvious that short-term effect of fishing on the AR is always to increase the catch, but many fishers did perceive the longer-term effect of decreasing catches. The potential negative effect of the AR on catch when there is high fish attraction combined with high fishing pressure on the AR might explain the reluctance of a part of the fishers community to AR deployment Fig. . In part16 but precise estimation of this parameter cannot be inferred, as this would need, ideally, individual fish trajectories. Future field research on the attraction effect may permit estimating the AR attraction parameters. The model sensitivity test showed that the stronger the attraction parameter, the better the impact of the AR for the fisheries in case of no or small fishing effort on the AR . Local fishers perceptions were globally in line with the model prediction that this AR fails to improve fisheries yield when surveillance is not in place to ensure AR regulations are observed, despite effective fish attraction and production existing in the AR.At the time of the survey, the surveillance system set up by the co-management entities was not operational in our case study, because it was dependent on temporally limited external financing. These limitations are typical of short-term projects that focus on a single restricted area for a pre-determined duration, usually up to two years  would lead to a very complex ecosystem model specific to the area (e.g. 26), with necessarily more assumptions. This model would necessarily be more difficult to share with fishers and other stakeholders. Both to simplify model structure and facilitate communication of results to stakeholders, we assumed in our model that the balance of entries exits and is in equilibrium, so that the migratory species did not affect the long-term equilibrium between fishing effort and fish abundance.The model predicted that enhanced production on ARs could not keep pace with unrestricted access, which might be particularly true in Senegal where fishing effort rapidly reorganizes itself according to local yields AR Fig. . These r27. We showed that, although production might have a limited effect on total catch, attraction can largely increase AR efficiency  if the rate of illegal fishing rate is very low or absent. Complex structures protect fish more effectively from small scale fishing gear28, including divers . Thus, ARs should be appropriately designed to help mitigate potential issues28. Such designs might be more costly, and do not exclude the need for surveillance, but would enhance fisheries management, especially when surveillance cannot capture low levels of illegal fishing.The design of ARs could be adjusted to reduce the effect of illegal fishing by passively preventing both industrial and artisanal fishing activity. Complex structures are more effective for fish production and attraction29, as has the failure of AR projects in a number of other developing countries9, which further deteriorate fishers trust and management plans efficiency30. In order to avoid that, NGO and governmental agencies driving ARs projects must consider that AR management induces collective costs before providing potentially collective gains. Thus, co-management that involves governmental institutions and fisher communities is required. Future management and adaptation plans for fishers, particularly in developing countries, should, therefore, focus efforts on raising long-term awareness of actors in both government institutions and fishing communities. At the level of institutional or development partners, long-term management costs should be included in the set-up of AR projects. For example, the local fishers committee of Yenne recently reported the establishment of a collective ship chandler whose profits are used to finance AR surveillance during the daytime. Subsequently, fishers noted an improvement in catches around the AR, even though illegal fishing likely continues on the AR at night . These observations support model predictions that low levels of illegal fishing might not disturb the positive impact of the AR. Alternatively surveillance effort could be supported by the community if benefits were managed according to ancestral traditions. Indeed, "no take area" regime on the AR would be in line with some past West African tribal laws, applied before the colonization era, which set marine area where fishing activities were restricted for occasional community celebrations. Collective processes where fishers and other stakeholders can design temporary no-take zones around the AR could increase fishers trust and compliance to the rules, fostering a positive socio-ecological feedback loop30.Finally, if socio-economic and governance conditions are not met, well-intentioned AR projects will likely disturb the existing equilibrium among fishers that have different levels of access to the AR. Poor governance of marine resources has previously been described in West Africa, particularly in Senegal33. Indeed, the communication of the resulting hybrid knowledge in specific events gathering local stakeholders helps strengthen fisheries co-management for the establishment of surveillance and regulatory frameworks. This phenomenon was experienced during the public restitution of the present study with the community, fishers, children’s from local schools and governmental stakeholders. Science popularization of the study results was in French and local language (Wolof) retransmitted on national news (available at https://www.youtube.com/watch?v=yQqFU2P4XZU). Posters were exposed during the event, including pictures of local fishers interviewed and statements reflecting their own perception of how the artificial reef interacts with ecological processes and fisheries dynamics. Straightaway, stakeholders and local promoters of AR publicly expressed their concern and willingness to prioritize the setting up an efficient AR surveillance independent from external resources prior to increase AR deployments. Knowledge hybridization could produce more specific models that could be used for warning and advice, for example by considering potential impacts of ARs on species compositions35, environmental parameters36, and cascade effects on the trophic food web37. However this approach would need to be adapted to local social-ecological governance, which might require dedicated political-anthropological studies (see concept of adaptive co-management32).Hybridization of local and scientific knowledge, through the integration of natural sciences and social sciences, is key point for governance setting38 to implement ARs, including considerations of long-term governance.In summary, best practices should involve all stakeholders, consider local specificities, such as site configuration, governance, ecosystem, availability of ad hoc human and financial resources for AR surveillance, and define AR volume and design accordingly to these parameters. Thus, if plans exist to deploy ARs at large scales we recommend that legislation is strengthened, with detailed Environmental and social Impact AssessmentsFish population growth can be described using a logistic equation;Fisheries landings can be described as a product between fishing effort, fish density, and a catchability coefficient;Fishing effort increase or decrease according to the benefits of the fisheries;Artificial reefs have both fish attraction and production effects.The mathematical model considered a coastal area in which fisheries are managed by the deployment of an AR in a no-take area surrounded by a fishing zone. It is a demonstration tool based on four generally accepted assumptions:14. In the current study, the model assumed there was some “illegal” fishing in the no-take area . “a” was the parameter determining fish mobility; the higher the value of this parameter, the faster fish biomass reached the IFD. It was assumed that the fish population was isolated from other populations . The fishery associated with this fish community was defined by the cost per unit effort, c, the market price, p, and the fish catchability coefficient, q; however, the latter could also be interpreted as a property of the fish. The carrying capacity of the studied area, K, is considered uniform prior the immersion of ARs. Based on the published literature, we formulated the hypothesis that ARs can: (1) add an additional carrying capacity per unit of AR volume, δk, to the area where they are deployed, accounting for the production effect; and (2) modify fish IFD between the fishing area and no-take area, through the attraction effect. Given “V”, the volume of ARs, and “α”, the proportion of the fishing area that is no-take area, the total carrying capacity of the no-take area was given as αK + Vδk. Similarly, the carrying capacity of the open access area was given as (1-α)K. The attraction effect was simulated by an “attraction function” , and ε <  < 1 stands for a small dimensionless parameter with the purpose of discriminating “slow” and “fast” time scale processes. Growth and fishing mortality were assumed to occur at a slow time scale compared to fish and boat movement.Note, here, 42 for total fish biomass n(t) and fishing effort E(t) . See Supporting Information Sect. Assuming the fast movement of fish and boats between the two zones, we derived a reduced modelmentclass2pt{minim15], at least for territorial AR-associated species, such as Epinephelus costae, which is one of the species inhabiting the AR with the highest commercial value16.Using this model, we looked for the effects of illegal fishing  for different volumes of ARs under different attraction and production conditions. The parameter values used here Table  were sete.g., captain, sailor, ship owner), and affiliation (or not) of fishers to their local fishery committee . Ten fishers per village were interviewed separately, totaling seventy interviews across the seven villages surveyed. The questionnaire and field report, as well as a data table on which all responses were compiled, are provided in the supplementary data.The mathematical model was complemented by a field survey in 2014 to elucidate the perceptions of fishers on the effect of an AR and its management. The survey presented here was designed to capture the perceptions of fishers on the ecological function of the AR and its effect on local fisheries dynamics based on the key biological processes also included in the mathematical model . The survey also documented the knowledge of fishers and the extent to which they adhere to actual rules in the co-management of the AR. The survey started with a meeting of the seven village chiefs and notables who helped facilitate the survey at seven locations near the AR . For details on the social survey, see the Supporting Information Sect. The questionnaire consisted of 36 questions. The first 10 questions gathered information about the interviewed fishers, including their social position among fishers, experience, fishing gear used, and favored target fish species. Then, five multiple choice general questions were given to assess respondent opinions on why fish depletion occurred in the area, the acceptance of management measures, changes to catches perceived after AR implementation, and property perception of the fish present in the AR. Four further questions were asked about the limits and characteristics of the coastal area where the respondents fished, and how the fishing area is shared with others fishers. Finally, 17 semi-open and open questions focused on the ecological processes of fish attraction, production, and spill over  and the Environmental and sustainable development Senegalese Ministry (MEDD). The experimental protocol (survey) was reviewed and approved by both national institutions. All participants to the survey did it voluntary. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.Supplementary Information.


The aim of this study was to explore psychiatrists’ experience of vocational rehabilitation for patients with mental illness. The study employed a qualitative design to explore psychiatrists’ experience of vocational rehabilitation. Ten psychiatrists, five women and five men, 33–62 years of age (median 40), were interviewed. All of them worked with patients at Sahlgrenska University Hospital. The interviews were analyzed using inductive thematic analysis. All participants considered vocational rehabilitation to be of great importance for patients’ well-being and health. The results were characterized by two opposite experiences: frustration and agency, these were the two main themes in the analysis. All narratives embraced both experiences, but some reflected more frustration and others more agency. In order for the psychiatrist to master the assignment, there is a need for further training and supervision. The psychiatrist’s role, as well as other professional roles within the team, requires clarification, and the support from rehabilitation coordinators and occupational therapists should be enhanced. There is a need for improved cooperation with external actors. Mental illness often lead to recurrent episodes of impaired work ability, which incurs high costs for both the affected individual and the wider society , 2. VocaIn Sweden, the conditions for physicians and other actors working with vocational rehabilitation have gone through substantial changes . Around Vocational rehabilitation is a shared responsibility including stepwise interventions and assessments from various professionals in the mental health services, the municipality, the Social Insurance Agency (SIA) and the Public Employment Service (PES). The SIA is responsible for the coordination of these different interventions .The physician’s responsibility in vocational rehabilitation is to determine the disease or disability and its effect on the patient’s functioning and work ability, discuss advantages and disadvantages of sick leave with the patient, determine the degree and duration of sick leave, consider alternative interventions, provide a sickness certificate if applicable and collaborate with other actors . Actors In vocational rehabilitation, the physician takes on two sometimes conflicting roles: being both the treating physician and the medical expert . AccordiThere are no qualitative studies on psychiatrists’ experiences of working with vocational rehabilitation. Most of the Swedish qualitative studies have been performed in primary care settings. In this clinical context, physicians have described a lack of knowledge of the social security system, the patient’s workplace and the labour market in general . PhysiciA study on psychiatrists’ experience of working with vocational rehabilitation for patients with mental illness is motivated for several reasons. According to the regional medical guidelines, psychiatry is supposed to treat mental health patients with complex symptoms and low function, or patients who have received treatment in primary care which has not led to improvements . FurtherThe study employed a qualitative design to explore the meaning and significance of psychiatrists’ experience of vocational rehabilitation through interviews at Swedish clinics for patients with mental illness. The study design was reviewed and approved by the Swedish Ethical Review Board .All psychiatrists (N = 10) at two outpatient clinics were asked to participate in the study. They received information at a physical meeting or by telephone. Information included the aim of the study, the voluntary nature of participation and a statement that confidentiality would be assured. This generated five participants. Then five more participants were strategically sampled from the psychiatrists (N = 12) working at two other outpatient clinics to maximize data variation. Strategic sampling was performed according to variation in sex, age, professional qualification (Swedish or foreign) and length of work experience as a psychiatrist. Strategic sampling was performed with help of the managers of the outpatient clinics, who mediated contact between the researchers and the psychiatrists. Two sampled informants who were asked to participate declined. All participants signed a written consent form before data collection.Ten physicians with a specialist qualification in psychiatry, aged between 33 and 62 (median 40) years, five men and five women, from four outpatient clinics were recruited to the study. These clinics treated patients with mental illness such as depression, anxiety, personality disorders, PTSD, OCD, Bipolar Disorders (without Type 1 Disorder) and neuropsychiatric conditions. The clinics, in different geographic areas of a large Swedish city, were organizationally part of the department of psychiatry for patients with mental illness at Sahlgrenska University Hospital. The participants had between 4 and 21 (median 9) years of experience as specialists in psychiatry. Three had a Swedish medical degree, and seven had a medical degree from another European country. Five had completed their training as resident physicians in Sweden, five of them abroad.The interviews were performed in the participant’s office. The interviews lasted between 34 and 72 min. The first author conducted six interviews and the second author conducted four. The interview guide was semi-structured and covered three areas: the psychiatrist’s experience of vocational rehabilitation, perceived problematic and helpful factors in collaboration, and how the participant would prefer the vocational rehabilitation process to be organized. Participants were asked to talk about vocational rehabilitation interventions, except those which are strictly pharmacological or psychotherapeutic. All questions were open-ended to invite the psychiatrists’ own thoughts and experiences. Follow-up questions were used to a varying extent, depending on how much detail the participant supplied spontaneously. All interviews were audio-recorded and transcribed verbatim.The interviews were analyzed using inductive thematic analysis, which is described as a flexible qualitative method of analysis where patterns of meaning in data are reported through a rich and detailed description of themes . The anaIn the first phase, the authors familiarized themselves with the data by reading the transcribed interviews and making notes, generating an initial list of ideas that were interesting and were relevant to the aim. In the second phase, the first author labelled short extracts of the psychiatrists’ statements with descriptive codes according to their content, semantic or latent. The coding was performed without trying to fit the material into any pre-existing framework and continued until the content of the entire data set was coded. In the third phase, the codes were sorted into potential themes. This process generated an initial mind map of themes and sub-themes. The themes and sub-themes were then discussed within the research group, considering how each theme contributed to the overall narrative of the material in relation to the research questions. New ideas that emerged were then used by the first author for recoding the material, generating a new mind map that was discussed in the research group. This process was repeated twice until the mind map was refined and a candidate thematic map had been created. The codes were then sorted into two overarching themes reflecting either the sense of agency or frustration in the process of vocational rehabilitation. In phase four, the themes were reviewed by the first author, reading all the coded data extracts for each theme to ensure that a coherent pattern was formed within each theme. After that, the entire data set was re-read to ensure that the themes accurately represented the data. In phase five, the essence of each theme was further defined and refined by the researchers, also further determining which detailed aspects of the data the theme captured. Themes and sub-themes were described in detail and the themes were given names. As the sixth and final phase, the report was produced. Direct quotes were used in the report to allow readers to evaluate the analysis. During the process, Braun and Clarke’s  15-pointfrustration and agency. All narratives embraced both experiences, but some were more characterized by frustration, others more on agency. These experiences form the two main themes in the analysis. They can be read as two in-depth descriptions of experienced problematic factors and facilitating factors in relation to vocational rehabilitation.All participants considered traditional vocational rehabilitation  to be of great importance for patients’ well-being and health. But the narratives were characterized by two opposite experiences in relation to vocational rehabilitation: Lack of competence, Lack of support, Lack of power and Questioning of the psychiatrist’s role.The overarching theme of frustration brings into focus an inner experience characterized by feeling responsible but not being able to help the patients. The experience of frustration is outlined in the four sub-themes I think we should get better training, at least about insurance medicine. We should know more about it, and how it works, and what is most relevant. We get it in some way but not in such detail that we would like to have. (Participant 10).Participants described the procedures of vocational rehabilitation as unclear and difficult to overview. Some participants wished for increased clarity regarding general routines of how to work with vocational rehabilitation at the outpatient clinic, including concrete instructions. Furthermore, training regarding the social insurance system was described as insufficient or inappropriate, not generating the necessary understanding of the processes of vocational rehabilitation.Uncertainty about current research in the field of vocational rehabilitation was expressed by most participants, and some described frustration arising from a lack of applicable research in the area: “Regarding returning to work, research is practically non-existent” (Participant 1). Failure to follow the formal descriptions of sickness certification was related to this frustration.So I think, for example, that the patient could work in some kind of adapted job. (…) But the patient himself doesn’t want to and has been on sick leave for 10 years. Other doctors have met him and I just renew the sickness certificate. (Participant 8).In the following example, the participant describes how he renews the sickness certificate even if the assessment is that the patient has a work ability, a procedure that is not in line with SIA guidelines.Lack of competence was associated with being unfamiliar with the Swedish social insurance system and the Swedish organization of interventions in vocational rehabilitation. This uncertainty was particularly regarded as an obstacle by participants having either an overseas education or having done the training as a resident physician in another country. This was also the case for participants who were new at the clinic. “Because I am new here in Sweden, I came here four years ago, so I do not know the system very well.” (Participant 8).During a period of one calendar year, I would suspect that the patient has at least two to four changes of administrator handling the patient’s case which means an incredible uncertainty on both sides. (Participant 3).Feeling a lack of power in the process of vocational rehabilitation was related to feelings of frustration and anger. One aspect of this experienced powerlessness was when external actors made decisions that differed from one patient to another, or had a rapid turnover of staff dealing with the patient, thus making their decisions arbitrary and difficult to influence.The participants stressed that collaboration with the SIA and PES was crucial to the process. Some had the impression that staff at the authorities seemed to lack time to communicate or meet when it was needed. As a result, the participants felt less able to influence the process. “There are such difficult working conditions at the SIA that they have not been able to attend as many coordination meetings as they did before.” (Participant 5).So it is also that, with the SIA, you speak ‘disability language’. And for rehabilitation, you speak ‘habilitation language’. For example, the Employment Office as an actor is very well aware of that dilemma: Should one describe the sickness or should one promote the healthy side? But it is precisely that, that even related actors in the social security system no longer speak the same language. (Participant 3).Problems in the communication between the SIA and PES was also described as destructive to the process. When they could not agree on financing, or on a suitable intervention for a patient, the process could get stuck. One explanation for the difficulties in collaboration was differences in language traditions.As a doctor you stretch the boundaries more and more to declare dysfunction because … how should I put it … a more reasonable or moderate degree of dysfunction is not accepted at all as objective evidence of some degree of reduction in work ability. (Participant 3).Participants stated that the demand from the SIA for specific formulations concerning objective evidence in the written sickness certificates was problematic, since it led to a devaluation of the role of the psychiatrist as a medical expert.Now the SIA is changing rules all the time, but something that has been bothersome (…) I don't know if they have new rules, but for a while they demanded that we should have very precise planning in connection with return to work, that you would know exactly when the patient could go back to which degree of work. (Participant 5).Lack of power was also experienced when the SIA or PES rules were perceived as obstacles. For example, the rule stating that the individual plan must include work training increasing from 25 to 100% over a year was considered unrealistic for patients who had been on sick leave for many years. Furthermore, the rule that the patient must have 25% work ability to be granted work-oriented interventions from the SIA or PES was considered a problem. Patients with less than 25% work ability were sent instead to, for example, general activity centres run by the municipality, which had no particular focus on supporting vocational rehabilitation. Frequent changes of the rules that governed the decision-making of SIA and PES administrators were also described as a problem.The general lack of jobs suitable for this vulnerable group of people was also regarded as problematic. Participants described that the patients tended to be unattractive on the labour market because of their fragility and need for adjustments in work demands. “In this society there is a problem for our group of patients, that we don’t have many workplaces of that kind.” (Participant 1).As a doctor, you have two different roles, you must be on the patient’s side, but at the same time, you should be a person in authority and be able to act in the process as a medical expert. It can sometimes be a little hostile … or it complicates the relationship with the patient a good deal. (Participant 6).Frustrated participants tended to question their role in the process. This included questioning the fact that both psychiatrist and primary physician were responsible for sickness certification. Being a medical expert in social insurance decisions and at the same time being responsible for the clinical treatment of the patient was described as a challenge by some participants. The two roles were sometimes found to be in conflict, for example when the participant assessed that the patient had a level of functioning sufficient to be able to work and the patient did not agree.Participants also felt burdened by being responsible for an assessment that impacts the patient’s economic situation. Other expressed the wish that other social authorities would take more responsibility for vocational rehabilitation. “I would like to have another authority, responsible for vocational rehabilitation (…), motivational dialogs, offering adapted employment, physicians, sickness certification, everything.” (Participant 8).Orientation, Having adequate support and Mastery of procedures.The experience of agency in the process of vocational rehabilitation is described in the sub-themes There is a need for some kind of orientation map, the one that I have drawn here (…) I have come up with it myself and it is just my way of being able to orientate myself among all these different interventions, authorities and actors. (Participant 6).Among participants who described themselves as active and competent in the process of vocational rehabilitation, narratives were characterized by feeling oriented in the process and their role. Some participants likened their sense of orientation to having a mental map of the process.You identify what level in the process we are at and chart what we would need to do more to move forward in the process. So that structure could be imagined, because in some way you have a map of it, in different steps, where you try to place yourself together with the patient. (Participant 1).Being sufficiently oriented in the process of vocational rehabilitation was described as a necessary prerequisite for agency, enabling progression through the different steps of the process.Learning from experienced colleagues, working with rehabilitation, reading scientific articles and searching for information on the internet were described as different ways to gather information that helped them to acquire agency. “The occupational therapist was a driving force (…) She also – about research and what is going on – sent us information and so on, and there we had many good discussions.” (Participant 9).Training from the SIA in writing sickness certificates, together with templates used at the clinic, were described as helpful. “I got training from the SIA, who taught me how to write a [sickness] certificate.” (Participant 4).She can meet the patient herself (…) and then she usually does it in a really thorough way or delves deep into the case in some way. (Participant 2).Among participants describing a sense of agency, the experience of having access to adequate internal and external resources was prominent. Psychiatrists who reported receiving sufficient support from other professionals at the outpatient clinic during the rehabilitation process, commented that this enabled their sense of agency. All participants described collaboration with a rehabilitation coordinator at the outpatient clinic as valuable. Rehabilitation coordinators were described as supportive in making assessments, planning interventions and handling collaboration with external actors.Then you have to have it as a theme at the team conference (…) you also have to talk work-oriented rehabilitation, what kind of employment does the person have, is it thought that they should be able to start working, for when you start there, then you start to become more conscious in each treatment intervention (Participant 1).For the psychiatrist to experience a sense of agency, he or she had to feel supported by the outpatient team and feel that vocational rehabilitation was identified as an important issue also by the team.“I think personal continuity is very important, genuine commitment.” (Participant 6).For the psychiatrist to experience agency there also had to be well-functioning cooperation with external actors. When forming a plan for rehabilitation, continuity at the SIA and optional interventions on their part were emphasized as important. Otherwise the participants perceived it as impossible to plan and make a prognosis for the patient’s return to work. To build collaboration with a genuinely committed and independent administrator at the SIA was described as an integral part of a successful vocational rehabilitation process. The ability to collaborate and communicate with officers at other authorities was needed to modify the planned interventions or steps in the process. “I suppose my feeling is that once we have meetings and the SIA is there, things get easier.” (Participant 2).Another thing that has helped a lot is when there is information and ongoing projects to help patients getting into projects that support young people on sick leave to join the job market. (Participant 2).Participants mentioned interventions provided by coordination associations organized by municipalities with the aim of bridging gaps between SIA, PES, social services and health care, often targeting individuals far from the labour market, as particularly helpful.There is a fear of failure (…) they think about all 15 previous trials. And it is very important also to know what has been done previously (…). Many times they have done some work training with insufficient support or they increased their working hours too quickly. (Participant 7).This theme captures the experience of being skillful and capable in performing various procedures relevant to vocational rehabilitation. Participants expressed a sense of agency through influencing and motivating the patient and exerting influence in the decision-making of other actors. To define a reasonable goal based on the patient’s ability and wishes, followed by continual evaluation, was expressed as an important part of the motivational work. Furthermore, helping the patient to take the next step in the process by giving reasons and explanations of why previous efforts had failed was given as examples of motivational interventions.I try to set the tone and the agenda on those meetings. So I usually start with a small long monologue and talk a little about the process and the results so far. I also describe the patient’s current state, and motivation, and my own thoughts. My strategy has been to have a consultation with the patient some half-hour before the actual meeting (…) we have then come to an agreement about what we want to present and achieve. (Participant 6).The experience of confidence in influencing other authorities in their decision-making in the vocational rehabilitation process was prominent in narratives of agency. Taking an active role in coordination meetings organized by the SIA was also important to master.The role is, I think, to follow up the process and support the patient and bring in the factors that are needed but also the required efforts at the clinic. During this period it is we as doctors who many times follow up the whole process, but then yes … people of other professional categories sometimes do some interventions and follow up a little further along and at times a little less. And it is important that municipal actors, like the employer, the SIA and the Employment Office, collaborate. (Participant 7).The management of vocational rehabilitation processes was described as implying an initiation of the process, facilitating the creation of a plan for the process, bringing the process forward and carrying out a continual evaluation.The present qualitative study is the first study to investigate psychiatrists’ experience of vocational rehabilitation within psychiatry. The psychiatrists who took part in the study experienced agency as well as frustration in their role. Frustration was characterised by shortcomings in terms of expertise, support, and power. The participants reported a lack of knowledge of routines, laws, regulations, concrete methods, and relevant research into vocational rehabilitation. The participants also expressed a lack of support from the psychiatric team, and stated that other professionals, such as occupational therapists and social workers, were not always available due to work commitments. Lack of power was experienced in dealings with external agencies, such as the SIA or PES. There was a high degree of frustration with regard to the questioning of the psychiatrist’s role in vocational rehabilitation. Experience of agency was characterised by orientation, receiving sufficient support, and mastering relevant procedures.The reported lack of expertise has also been reported in previous studies in other clinical settings. Physicians have reported a need for more knowledge about the labour market and the social security system , 27 and Communication difficulties and limited collaboration with other agencies, such as insurance boards, have been reported in other studies , 30, 34.All participants reported that rehabilitation coordinators help discharge tasks related to vocational rehabilitation. This is in line with previous research into physicians’ experiences when working with rehabilitation coordinators. In a survey conducted among a very large population of physicians who had access to rehabilitation coordinators, 60% stated that the involvement of rehabilitation coordinators was of considerable value in terms of improved quality when working with sickness certification, and 31% stated it was of moderate value . In primIn an attempt to overcome these difficulties and work towards improving the potential for psychiatrists to orientate themselves, receive sufficient support, and master relevant procedures, there is potential to make structural improvements. There is a need for education and training of psychiatrists in the vocational rehabilitation process, along with relevant research and a clear definition of the roles of the psychiatrist and insurance medicine. Case conferences and coaching by colleagues with greater expertise in rehabilitation could be further ways to improve orientation. The results suggest that the need for support could be even more pronounced for psychiatrists who completed their specialist training in countries other than Sweden.As regards the provision of evidence-based methods to facilitate return to work, psychiatry requires better structures when collaborating with the SIA, PES, and external bodies. A coordination association is an example of an external body with the potential to raise the level of collaboration. A national report suggests that interventions by coordination associations help narrow the gap between the individual and the labour market .The results indicate a need for the psychiatric team to focus more on vocational rehabilitation by bringing this issue to the fore when planning further patient interventions. There is also a need for clarification of professional roles and responsibilities within the team.This is the first qualitative study of psychiatrists’ experiences of vocational rehabilitation. It includes a relevant range of topics and a diverse participant base in terms of years of working as a psychiatrist, those who qualified in Sweden and those who qualified abroad, and representation across a variety of outpatient clinics. This has enabled a rich body of data to be collected that reflects a wide range of perspectives. The present study could provide valuable information to further develop vocational rehabilitation within psychiatry.The number of participants in the study (n = 10) was limited and they were all based in Gothenburg. There could be local variations in the relationship between the psychiatric profession and other relevant bodies, such as the SIA and PES. Despite possible local differences within Swedish psychiatry and within the social insurance systems in different European countries, we believe that the results from this study could contribute to acquiring a deeper understanding of the difficulties facing psychiatrists when working with vocational rehabilitation. It should be borne in mind that the participants in this study completed their specialist training before insurance medicine was included in the specialist training syllabus in 2015, and these results may not be as valid in the case of psychiatrists who completed their training after 2015.Future research dealing with further perspectives on vocational rehabilitation within the healthcare system, such as those of patients and other professionals, including rehabilitation coordinators, could contribute to a broader understanding of vocational rehabilitation.


Populus spp. are among the most economically important species worldwide. These trees are used not only for wood and fiber production, but also in the rehabilitation of degraded lands. Since they are clonally propagated, the ability of stem cuttings to form adventitious roots is a critical point for plant establishment and survival in the field, and consequently for the forest industry. Adventitious rooting in different Populus clones has been an agronomic trait targeted in breeding programs for many years, and many factors have been identified that affect this quantitative trait. A huge variation in the rooting capacity has been observed among the species in the Populus genus, and the responses to some of the factors affecting this trait have been shown to be genotype-dependent. This review analyses similarities and differences between results obtained from studies examining the role of internal and external factors affecting rooting of Populus species cuttings. Since rooting is the most important requirement for stand establishment in clonally propagated species, understanding the physiological and genetic mechanisms that promote this trait is essential for successful commercial deployment. Adventitious roots (ARs) are formed post-embryonically from new cells of non-root tissues such as leaves and stems. Many species can produce ARs during normal development, but also in response to environmental stresses such as wounding, flooding, or nutrient deficiency . The abiPopulus is among the most economically important woody plants  in which cuttings contain preformed and newly formed AR primordia that co-exist  rooted 14 days after cutting, whereas the aspen (P. davidiana) did not produce roots at all. In another study, results showed that the variability in different rooting traits observed in 21 clones of Populus species was due to the combination of genetic variation between and within groups, as well as to the environmental conditions and the ability of each genotype to respond to the contrasting field conditions  cuttings, both initial carbohydrate and nitrogen content can limit root formation  . In the difficult-to-root hazelnut (Corylus avellana), rooting was positively correlated to the carbohydrate content in stem cuttings which was positively influenced by leaf photosynthesis activity  , the addactivity .Populus species  the age of the cutting is associated with a significant decrease in the rooting ability , for which the loss of ability to form ARs in mature tissues in response to auxin is not due to the lack of initial auxin responses, but rather to an intrinsic incapacity of cells to organize into a root meristem in response to auxin  cuttings, increasing the number of ARs per cutting  proteins which will be sent for degradation. In arabidopsis, it has been shown that auxin controls AR initiation by modulating jasmonate homeostasis. It acts through an Aux/IAA-ARF module including two positive regulators (auxin responsive factors ARF6 and ARF8) whose transcriptional activity is regulated by at least three Aux/IAA genes , and one negative regulator ARF17. This module controls the expression of three Gretchen Hagen genes  that encode acyl-acid-amino synthetases that inactivates IAA and jasmonic acid, a known AR inhibitor in arabidopsis hypocotyls  were upregulated during AR initiation, suggesting that the PagFBL1-PagIAA28 interaction may release PagARFs activity (GH3 genes to promote adventitious rooting. In arabidopsis hypocotyls it has been shown that ARF7 act together with ARF19 as positive AR regulators by activating the downstream transcription factors ORGAN BOUNDARIES DOMAIN (LBD) LBD16 and LBD18 , ARF8 overexpression promoted adventitious rooting, whereas the overexpression of the miRNA miR167, which targets ARF8 mRNA, negatively regulated rooting, as in arabidopsis  genes, which restrict mitochondrial energy production, resulting in an increase of the mitochondrial functionality. This dynamic regulation of mitochondrial homeostasis modulates the auxin pathway by the activation of the auxin efflux carriers PIN-FORMED2/5b (PIN2/5b)  regulate several plant developmental processes, including AR formation as shown for the complex regulatory mechanism including  Populus . In the bidopsis . Liu et bidopsis , was a pbolleana . Its oveitiation . These rPIN2/5b) , which aPIN2/5b) , promotiranching .WUSCHEL-related homeobox (WOX) genes WOX11 and WOX12 are activated by auxin during the first step of de novo root organogenesis  genes which are involved in cell division and differentiation  were also shown to be involved in AR development in trees. In arabidopsis, the SCR gene is involved in the organization of the root meristem  transcription factor PeSHR  family, was found to be induced by auxin and to positively control rooting of the hybrid P. tremula × P. alba cuttings , which induces auxin biosynthesis thereby promoting ARs in arabidopsis leaf explants. ERF109 is later inhibited by JASMONATE-ZIM DOMAIN (JAZ) proteins to prevent hypersensitivity to wounding (Nicotiana tabacum) and pea (Pisum sativum) stem cuttings, suggesting that JA could be a positive regulator of AR formation after wounding in these species (in vitro (ETHYLENE INSENSITIVE3/ETHYLENE INSENSITIVE3-LIKE1 (EIN3/EIL1) signaling pathway (Jasmonate (JA) participates in the regulation of several physiological processes and is especially important in the response to biotic and abiotic stresses . The rol pathway . In contwounding . A sharp species . Neverth species . In arabin vitro . It was  pathway .PuHox52, from the HD-Zip I transcription factor family, is a positive regulator of AR development downstream of JA in Populus ussuriensis  are plant hormones that promote cell division and are involved in different processes of plant growth and development. They act as antagonists of auxin in many aspects of development. For example, a high auxin/CK ratio induces root formation, whereas a low ratio stimulates the formation of shoots. Thus, CKs are known to inhibit adventitious rooting. Populus cuttings, PtRR13), which acts in the CK signaling pathway, reduced AR formation in cuttings of the hybrid P. tremula × P. alba (COV1) and a PLEIOTROPIC DRUG RESISTANCE TRANSPORTER9 (PDR9), an auxin efflux transporter, whereas it inhibited the transcript expression of two AP2/ERF genes TINY-like. In the proposed model CK signaling is reduced after shoot excision at the base of the cuttings, which enables coordinated expression of ethylene, auxin, and vascularization pathways leading to AR development. Moreover, in Populus tomentosa, the overexpression of CKX2, a cytokinin oxidase that converts active CKs to the inactive form, in the roots enhanced root growth without modifying shoot growth  hypocotyl cuttings, where a peak of ET was observed that was correlated with AR formation  synthase and oxidase genes, at the base of cuttings of the P. tremula × P. alba hybrid, after shoot excision. These genes code for enzymes of the ET synthesis pathway, and their increased expression might explain the ET peak observed after wounding in the study by ACC synthase and oxidase genes were rapidly induced after cutting, suggesting that ET is required for early adventitious root induction  is a gaseous plant hormone which regulates many physiological and developmental stages and mediates adaptive responses to biotic and abiotic stress factors . In arabormation . In the ormation . Ramireznduction . In a ren poplar .P. tremula × P. alba showed that ETHYLENE RESPONSE 2 (ETR2) and the RING-type E3 ligase XBAT32 genes play a role in AR development, since both over-expressing lines showed increased rooting  seedlings where ACC treatment increased AR development (Picea abies) , an inhibitor of t length . Similarelopment . Ethylena abies) , but a sa abies) .Eucalyptus cuttings, at high auxin levels ET inhibits AR formation  repressed AR development , the Populus ortholog of A. thaliana STERILE APETALA (SAP) belonging to the AP2-domain transcription factor family, is a positive regulator of AR development. BL gene expression was correlated with PtAIL1 transcript abundance, suggesting that the rooting-inducing effects of BL could be mediated via modulation of PtAIL1 expression.In ormation , whereaselopment  and propPopulus, as well as its interaction with other plant hormones in this process. More studies are needed in order to confirm the positive effect of ET during the induction phase and the negative effect of ET in later rooting phases in Populus.These studies demonstrate the significant role of ethylene in AR formation in Populus. In the aspen P. tremula, the application of paclobutrazol (PBZ), an inhibitor of GA biosynthesis, was found to promote AR formation, whereas GA treatment had a negative effect on AR development in in vitro culture cuttings  gene, which is a repressor of GA signaling, increased the number of ARs  was increased two to three times compared to the control line. Exogenous GA application could not inhibit AR formation in these transgenic lines as it did in the wild type. 35S:PcGA2ox1 and the insensitive 35S:RGL1 transgenic poplars had increased lateral root proliferation and elongation under in vitro and greenhouse conditions, and that these effects were reversed by exogenous GA treatment.The role of gibberellins (GAs) in AR formation is still unclear but a few studies have demonstrated that exogenous applications of gibberellic acid are inhibitors of AR formation in cuttings . Moreover of ARs . SimilarPopulus. Nevertheless, more studies are needed in order to determine the developmental stage at which GAs are detrimental for AR development. Indeed, GA20ox1-OE aspen was found to exhibit poor rooting that affected plant survival, but those plants that produced roots had the same total root biomass as the wild type at later developmental stages. This suggests that the effect of GAs varies with the root development stage  ABA has been shown to negatively control AR emergence  with different rooting abilities. No differences in ABA content were found between the two genotypes, suggesting that the endogenous content of ABA in the shoots is not correlated with the rooting ability of these two genotypes. Nevertheless, treatment with ABA added to the medium reduced the number of roots in both genotypes, suggesting that exogenous application of ABA negatively affects adventitious rooting in Populus.Abscisic acid (ABA) is a plant hormone that helps plants to adapt to stresses. ABA is often accumulated under water stress and inhibits cell cycle progression. In flooded rice (mergence . The tomild type . In grapcuttings . In PopuPopulus transgenic line overexpressing a cytokinin type-B response regulator (PtRR13), the Brassinosteroid Enhanced Expression (BEE) gene was in the top five most significantly up-regulated transcripts 24 h after cutting, suggesting that this gene is affected by the overexpression of PtRR13, and that BEE may also be involved in the negative regulation of adventitious rooting in this transgenic line (Brassinosteroids (BRs) are plant steroid hormones that play a role in various developmental processes such as cell elongation and division, as well as in biotic and abiotic stress responses . The effnic line .Strigolactones (SLs) are plant hormones derived from the carotenoid pathway. They participate in different physiological aspects of plant development such as apical dominance and root growth . SLs aremax4 mutant, which has reduced SL synthesis  and SL-insensitive (d3) rice mutants exhibited reduced AR production compared to the wild type , an inhibitor of GABA degradation, was applied, AR growth decreased. With both GABA at the highest concentrations and VGB applications, endogenous GABA levels were increased, whereas in the lower GABA treatments the endogenous content decreased. These results provide evidence that endogenous GABA accumulation is negatively correlated with AR formation in poplar  on AR formation in the hybrid poplar n poplar .P. alba and P. canescens, the external application of phenolic substances such as pyrogallol or salicylic acid improved rooting. This beneficial effect was greater when the natural ability to form roots was low. Moreover, addition of these compounds enhanced the positive effect of auxin , salicylic acid, a phenolic acid involved in biotic and abiotic stress responses, promotes AR formation via the process of hydrogen peroxide (H2O2) accumulation  , a chemical H2O2 scavenger, had the opposite effect  . Recentl of H2O2 . In addie effect .2O2 or other organic peroxides. Many studies have shown a correlation between peroxidase enzyme activity and the rooting process, and it has even been proposed that changes in peroxidase activity could be used as biochemical markers for rooting phases in several species  cuttings, where an ectomycorrhizal fungus stimulated branching of the adventitious roots , the rooting of microcuttings grown in media with exogenous auxin (IBA), was better under fluorescent light than under light emitting diodes (LEDs)  . To dateransport .Populus × euramericana. Their results showed that soil moisture as well as pre-soaking of cuttings had a positive effect on rooting. Water-stressed cuttings took longer to root and formed fewer roots, whereas pre-soaked cuttings rooted better, especially in drier soil.Pre-soaking cuttings in water is a pre-planting treatment that increases the success of rooting and enhances the survival and growth of the plants. Populus cuttings. Removing 50% or more buds from the cuttings of ten poplar clones significantly reduced the number of ARs, but had no effect on the total root dry mass  whereas cooler temperatures were more effective for rooting in the hybrids evaluated  to 30°C in a controlled air temperature, had a positive impact on root growth as well  ratio favors rooting, whereas a low one increases shoot growth. Nevertheless, in some studies it has been shown that the number and length of roots are positively correlated with the initial total N content in the cuttings . Only coew roots , whereasew roots . Similar nitrate .Zea mays), rice, and common bean (Phaseolus vulgaris). Under limiting P conditions, AR development was increased in these species  is another macronutrient that has been shown to affect AR formation in a variety of species such as maize ( species . Similarcuttings . Moreovecuttings .Cucumis sativus) and bean cuttings (WOX11 in the roots increased K acquisition efficiency and root biomass (Potassium (K) has been shown to promote AR formation in cucumber  also plays an essential role in AR formation. In the absence of Ca in the media, only 55% of cuttings from the hybrid aspen cuttings . RecentlPopulus alba cuttings  content has a negative effect on rooting of cuttings . In addicuttings . Becauseon phase .Populus. A more complete study examining how mineral nutrition and hormonal balance interact may be beneficial to understand AR development in Populus cuttings.It is clear that the content of macro and microelements affects AR formation in different species. However, very few studies analyzing the individual and collective role of these nutrients have been carried out in Populus. Plant establishment and survival, as well as adaptation to different environments is essential for breeding programs and they rely on a good rooting system. Different Populus genotypes present a broad variation in AR formation. Sections Aigeiros and Tacamahaca exhibit the best rooting performance and, therefore, are the most thoroughly studied and are normally used as elite parents. Nonetheless, traits from species belonging to other sections are desirable, such as the fiber quality from hybrid aspens, and introducing these traits by crossing is very limited. It is therefore important to study the factors and molecular bases that control AR formation in the different Populus genotypes in order to exploit the phenotypic diversity present in the genus.Adventitious rooting is one of the most important traits in clonally propagated trees such as Populus which seems to be the master hormone regulator of this process, but complex crosstalk with and between other phytohormones, and also with external factors exists and this complexifies the mechanisms controlling adventitious rooting throughout the rooting process. Thus, more detailed studies are needed in which these interactions are taken into consideration and different genotypes are analyzed.Adventitious root formation is a complex trait affected by many internal and external factors. Out of all of these, hormones seem, so far, to be the most important and central ones, as they not only interact with each other  but alsoPopulus genotypes, comparing results from different studies is very difficult and may not unravel the complex rooting process. It would be very interesting, though, to compare good and poor rooting genotypes in order to identify genes that are responsible for the differences observed. Performing transcriptomic analyses to compare extreme phenotypes could be a starting point to identify putative candidate genes that either induce or repress adventitious rooting in Populus species.In recent years, many transcriptomic analyses performed during the different rooting phases have been published and many genes involved directly or indirectly in the rooting process have been identified. During the first hours after wounding, many genes change their expression profile, suggesting that they may play a role in the rooting process at a very early stage. Nevertheless, because of the great diversity in the rooting ability of various FB conceived the manuscript, prepared the figures, and wrote the manuscript. CB reviewed and edited the manuscript. Both authors approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Social dilemmas are mixed-motive games. Although the players have a common interest in maintaining cooperation, each may try to obtain a larger payoff by cooperating less than the other. This phenomenon received increased attention after Press and Dyson discovered a class of strategies for the repeated prisoner’s dilemma (extortionate strategies) that secure for themselves a payoff that is never smaller, but can be larger, than the opponent’s payoff. We conducted an experiment to test whether humans adopt extortionate strategies when playing a social dilemma. Our results reveal that human subjects do try to extort a larger payoff from their opponents. However, they are only successful when extortionate strategies are part of a Nash equilibrium. In settings where extortionate strategies do not appear in any Nash equilibrium, attempts at extortion only result in a breakdown of cooperation. Our subjects recognized the different incentives implied by the two settings, and they were ready to “extort” the opponent when allowed to do so. This suggests that deviations from mutually cooperative equilibria, which are usually attributed to players’ impatience, coordination problems, or lack of information, can instead be driven by subjects trying to reach more favorable outcomes. Although their payoff is larger if they both cooperate, each of them has an incentive to defect. This game is interesting because if it is played only once, mutual defection is the only rational course of action, but, if it is played repeatedly and with a sufficiently long time-horizon, cooperation becomes a Nash equilibrium (NE). For this reason, over the years, the repeated version of the PD has become a fundamental element in studying the emergence of cooperation, both in biology16 attracted scholars’ attention to a somewhat neglected issue. They noticed that when a social dilemma is played repeatedly, there is always some conflict of interest because each player is tempted to cooperate less than the other to reap a larger share of the gains from cooperation. This result was not novel. One of the best-established results in game theory, the so-called folk-theorem, shows that when a game like the PD is repeated with a sufficiently long time-horizon, a host of new equilibria emerge17. In most of them, one player obtains a larger payoff than the other. The novelty of Press and Dyson’s result is that the repeated PD contains a class of strategies that they termed extortionate strategies (ExS), which secure for themselves a payoff that is never smaller (but may be larger) than the opponent’s, regardless of the strategy that the latter may employ. In this sense, ExS are unbeatable18. What makes this result particularly intriguing is that ExS are simple memory-one strategies: they base their current decision only on the outcome of the previous round.In a seminal paper, Press and Dyson19. First, since the PD is a symmetric game, asymmetric outcomes are hard to justify. Press and Dyson had already noticed that when two ExS are matched against each other, no extortion takes place because they both get the mutual defection payoff. This means that ExS can only succeed when they meet strategies that are not ExS, and hence they can never become dominant within a single population. This has led some authors to question whether ExS can play any significant role in the emergence of cooperation27.The literature that followed pointed out several weak points of this result28. Much less is known about whether human beings are able to discover them. To the best of our knowledge, the only study that has investigated whether human subjects adopt ExS in experimental settings is Becks and Milinski29. Their study reveals that ExS are observed only when an extra reward is given to the player who is able to gain more than the opponent. The authors concluded that ExS can only prevail when higher competitiveness is rewarded with extra gain.Second, in a standard PD, ExS are difficult to compute, which partly explains why they have long-escaped scholars’ attention. This issue is particularly relevant for experimental contexts in which human behavior is observed, because it is unlikely that bounded rational players discover them by trial and error. A few experiments have investigated how humans react when facing ExS, by observing how they play against computers programmed to play such strategies31 and may be more difficult to observe in experiments32.Finally, a question left open by Press and Dyson is whether ExS can be part of a NE when players are constrained to play memory-one strategies. This question is important because, if the answer is negative, ExS are bound to play a minor role in evolutionary models, even in asymmetric, multi-population settingsThese considerations suggest that ExS are more likely to play a role, both in theoretical models and in laboratory experiments, in settings that differ from the standard PD, at least in these three respects. First, we should look for asymmetric games where one player is in a better position to extort a larger payoff. Second, these games should contain ExS that are intuitive and relatively easy to discover. Finally, these ExS must be part of a NE.34 (STG) shown in Fig. To address these issues, we consider the Simultaneous-move Trust Gamepayoff premium. We label a strategy as extortionate if it is able to enforce a payoff premium when it is matched against its best reply. In contrast to the PD, in the STG only Player 2 can have ExS, as Player 1 can never get more than the mutual cooperation payoff. A second crucial difference is that the STG includes a very simple and intuitive class of ExS. These strategies prescribe to play C with a fixed probability q, independently from the previous history of the play. For this reason they are referred to as unconditional strategies. For an unconditional strategy to be ExS, the probability q must be sufficiently large to make C the best reply for Player 1. In the game in Fig. q must be larger than and in response to D. But if this is the case, then the optimal choice for Player 2 is to play D always, rather than in half of the rounds. The reason is that Player 1 (who only takes into account the previous outcome) cannot punish deviations from a mixed strategy, which proves that the initial strategy profile was not a NE. This result holds in general: as long as Player 1 can base her decision only on the previous round’s outcome, no NE exists in which Player 2 gets more than the mutual cooperation payoff . We circumvented this problem with the following experimental design. At the beginning of the experiment, subjects were equally divided to play either as Player 1 or Player 2, and they maintained the same role for the experiment’s entire duration. The experiment lasted for a variable number of rounds, not known to the subjects. At each round, subjects were randomly matched to play the STG in Fig. Depending on the type of information that we disclosed, two classes of treatments were obtained. In the Outcome treatments, Player 1 observed the action  that Player 2 chose in the previous round. In the Mixture treatments, Player 1 observed the frequency with which Player 2 played C in all the previous rounds.The link between our experimental design and the original Press and Dyson result is provided by our final theoretical result. We prove that the set of Nash equilibria for the Mixture and Outcome treatments (our stranger setting) is a subset of the set of Nash equilibria for a standard repeated STG  in which Player 1 bases her choice either on the previous round outcome (in the Outcome treatments) or on the mixed strategy chosen by Player 2 (in the Mixture treatments).The intuition behind this result is straightforward. From the point of view of Player 2, it makes no difference whether he faces a single memory-one Player 1 who only remembers the strategy Player 2 choose in the previous round, or a succession of different Players 1, each of whom can observe the strategy Player 2 used with the previous Player 1. From the point of view of Player 1, C is the best reply in the current round whenever she expects Player 2 to play C with a sufficiently large probability. It follows that if to play C is optimal for a patient Player 1 who interacts repeatedly with the same Player 2, it will also be optimal for a succession of Players 1, each of whom only plays once. In both cases, Player 1 will play a myopic best reply to the (mixed) strategy she expects Player 2 to play in the current round.Our theoretical result implies that Extortionate equilibria only exist in the Mixture treatments, and this gives us the following predictions:Prediction1 Player 2 can enforce a payoff premium in the Mixture, but not in the Outcome treatments.Prediction2 ExS are more frequent in the Mixture than in the Outcome treatments.The results from our experiment are in surprisingly good agreement with these predictions.37. The actual play of the repeated game was then carried out by the computer, and each subject received the payoff obtained by the program he chose (see Table A common problem with experiments involving repeated games is how to infer the repeated game strategies employed by the subjects from the actions (either C or D) they choose during the game. This problem is particularly acute in an experiment like ours, in which subjects were expected to use mixed strategies. To address this issue, we elicited subjects’ strategies by using two different approaches. In the Direct Response Method (DRM), subjects chose an action at each round of the game. In the Strategy Method (SM), subjects submitted their strategies in the form of simple computer programsFigure Figure In accordance with our Prediction 1, Players 2 are more likely to enforce a payoff premium in the Mixture, rather than in the Outcome treatments.Figure In the SM, we just considered the strategy submitted by Player 2, that is, the probability with which a subject had instructed the computer to play C. Since we allowed Player 2 to choose among five probabilities . Recall that, in our game, a strategy is extortionate if it prescribes to cooperate with a probability larger than . Remarkably, only one subject in the Mixture treatment chose to cooperate with a smaller probability. In the Outcome treatments, hich we also used t ExS were chosen by 63% of Players 2 in the DRM and by 48% in the SM . On the contrary, in the Outcome treatments, the most chosen ExS was 0.95 (that played C 95% of the times) in the DRM (chosen by 15% of Players 2), while in the SM, both 0.5 and 0.75 were chosen by 19% of Players 2. This finding is interesting because it shows that some Players 2 were trying to enforce a payoff premium by using an extortionate strategy, even in a context where they could not succeed because mixed strategies were not observable. Further details on Players 2’s strategies are provided in ‘Supplementary Information”.In accordance with our Prediction 2, full cooperation was the (only) modal choice in the Outcome treatments, while in the Mixture treatment the modal choice was  an extortionate strategy.We classified Players 1 according to the strategy that they chose in reaction to the information that they had received. For each treatment, we assumed that subjects used the strategies that appear in our theoretical model. (The details of the classification are in “Supplementary Information”).In the Mixture treatments, this implies that Players 1 used a step strategy, which cooperates only if, in the previous round, Player 2 cooperated with a probability larger than a threshold r 1 see “”, which For the Outcome treatments, we classified subjects as: AllD and AllC , TfT  Player 1 cooperated and Player 2 defected.We consider a general version of the STG in Fig. 1We are interested in how the equilibria for the repeated game are affected by two factors: the information on which players base their choices at every round, and their time preferences.observable outcomes, in which memory-one strategies could base their choice in round t only on the the outcome of the previous period, that is, on observable mixtures, in which memory-one strategies may base their choice in round t also on the previous (mixed) strategy profile, We first considered information. Press and Dyson, like most of the existing literature, focus exclusively on games with t rounds is Second, we explored how equilibria are affected by players’ time preferences. To do this, we departed from the existing literature by considering the general case in which players may have different discount factors, which we denote with q, which, in the stage game, is large enough to make C the best reply for Player 1. Simple algebra suffices in showing that this probability needs to be larger than As we anticipated in “i. The set of payoff profiles on the Pareto frontier is F, and P , implying that there are no extortionate equilibria on the Pareto frontier:We first state a very general result that has a relatively simple proof . With observable outcomes, if Player 1 is restricted to use memory-one strategies,the only efficient payoff profile that can be sustained in equilibrium is  played by Player 2 in the previous round, and the case in which she can also observe the mixed strategy previously chosen by Player 2. This model is in the spirit of45, where one long-lived Player 2 interacts repeatedly with a series of short-lived Players 1, and where each Player 1 can only observe how Player 2 behaved in the previous round.Before playing, each Player 1 can observe how the current Player 2 behaved in the previous round. Player 2 is given no information about the past behavior of Player 1. This puts a restriction on the type of strategies that the players can employ. Players 2 are constrained to use Let entclass1pt{minimaLet Players 1 be constrained to reactive strategies and Players 2 to unconditional strategies. Then (a)and (b)Our two experimental predictions are an immediate consequence of this proposition.a. This implies that, in the Mixture treatment, extortionate equilibria exist for any In our experiment, payoffs’ values are as shown in Fig. 146. Instructions were given neutrally, and actions were labeled as “Left” and “Right” for Player 2, and “Top” and “ Bottom” for Player 1.The experiment was run at the Cognitive and Experimental Economics Laboratory , with a total of 112 subjects (54 for the Outcome treatments and 58 for the Mixture treatments), all of which were students at the University of Trento. The study was conducted using Z-treeThe experiment was divided into two parts. In the first part (part A), subjects interacted directly with each other. In both treatments, subjects were randomly matched to play the STG for a minimum of 20 periods. To limit the end-game effect, a coin toss ensued at the end of every period after the 20th, to determine the ending of the game. At every round after the first one, Player 1 was informed of Player 2’s previous behavior. In the Mixture treatment, we provided information about the overall frequency with which each action was chosen. In the Outcome treatment, we gave only information about the last action taken by Player 2, thus forcing Player 1 to use a memory-one strategy.In the second part (part B) we asked participants to submit their strategies in the form of simple computer programs. In both treatments, a strategy for Player 2 was a probability with which the computer had to play C in every period of the game. The set of available strategies was plan of behavior: it specified one action (either C or D) to be played in the first period of the game, and a set of actions (one action for each possible contingency) to be played afterwards. In the Mixture treatment, a strategy for Player 1 had to specify, for each possible mixed strategy that Player 2 could have chosen, whether to play C or D. For example, a subject could instruct the computer to play C when the strategy played by the other player was 0.5, and D otherwise. In this case, the computer would play C in all and only the rounds in which it was matched with a Player 2 who choose to play C with probability 0.5. In the Outcome treatment, a strategy for Player 1 had to specify the action to take for each possible outcome (i.e. either C or D) of Player 2’s strategy. For example, if a subject instructed the computer to play C after C, and D after D, then the computer would play C in every period in which it encountered a Player 2 who played C in the previous period, independently from the mixed strategy chosen by Player 2.A strategy for Player 1 was a For each treatment, we collected all the strategies and let the computer play them for 20 periods. That is, in every period of the game the computer would match each Player1 with a different Player 2. In every period after the first one, the computer would check the previous behavior of Player 2, and it would select the corresponding action of Player 1 according to the plan of behavior that Player 1 submitted at the beginning of the game. Similarly, the computer would select an action for Player 2 according with the strategy that Player 2 submitted at the beginning of the game, and would thus determine the outcome of that round.The experiment lasted about 60 min. Payoffs were expressed in experimental monetary units (EMS).We obtained a written informed consent from all our participants. All experimental procedures were in accordance with the Declaration of Helsinki, and with the General Data Protection Regulation (GDPR) of the European Union. The study was approved by the Comitato etico per la ricerca  of the University of Trento.Supplementary Information 1.


Background: Previous studies have analyzed the association of aspect ratio (AR) on the ruptured intracranial aneurysm (IA), but the findings are inconclusive and controversial. Therefore, the study aimed to derive a more detailed estimation of this association between AR and ruptured IA in Chinese IA patients.Methods: The present work was a cross-sectional study. We retrospectively collected 1,588 Chinese patients with a single IA from January 2010 to November 2017. The relationship was examined between AR at diagnosis and ruptured IA. Covariates included data of demographics, morphological parameters, lifestyle habits, clinical features, and comorbidities. Binary logistic regression and two-piecewise linear models were used to analyze independent associations of AR with ruptured IA.Results: The results suggest that the association between AR and IA rupture was U-shaped. In the AR range of 1.08–1.99, the prevalence of IA rupture was 13% lower for each 0.1-unit increment in AR . Conversely, for every 0.1-unit increase in AR, the prevalence of IA rupture increased by ~3%  in the AR range of 3.42–4.08.Conclusion: The relationship between AR and ruptured IA was U-shaped, with the negative association at AR of 1.08–1.99 and positive association at AR of 3.42–4.08. Due to methodological limitations, the exact prevalence of intracranial aneurysms (IA) and the risk of rupture remains unclear . A curreThe prerequisites of predicted model development are based on the full clarification of ruptured IA-associated factors . AlthougWe performed a cross-sectional study based on a large sample. The interesting independent variable is AR. The outcome variable is the rupture status of a single IA .n = 55), feeding artery aneurysms-associated arteriovenous malformations (n = 67), fusiform IA (n = 29), or dissecting aneurysms (n = 47), leaving 1,588 individuals for the main analysis. Clinical information for each IA patient was obtained from our electronic medical record system. Participants' informed consent is not required in this study because of the nature of the retrospective study. The hospital institutional review board approved this study.There were 1,786 patients with IA initially collected between January 2010 and November 2017 at the Department of Neurosurgery, Zhujiang Hospital. Diagnosis of IA for all involved patients was confirmed by magnetic resonance angiography (MRA) or computed tomography angiography (CTA) examination or by digital subtraction angiography (DSA) after admission. We excluded individuals with multiple IA . The patient-specific geometries were reconstructed from 3D-DSA images to confirm the morphological parameters , 12.Aspect ratio: The aneurysm AR was determined as the ratio of the greatest perpendicular height to the mean neck diameter, where the mean neck diameter was evaluated as twice the mean distance from the neck centroid to the edge of the neck (the neck .Size ratio: The aneurysm-to-vessel size ratio (SR) integrates the geometries of the IA and its parent vessel and was explained as SR = (maximum aneurysm height)/(average vessel diameter) (iameter) .IA size: IA size was defined as the largest perpendicular distance of the dome from the neck plane (ck plane .The outcome in this study was IA rupture. The diagnosis of subarachnoid hemorrhage was confirmed by computed tomography (CT) scan.We collected information on covariates that are known risk factors for IA –22. ConsThe proportion of missing data was low (<5%) for all variables, multiple imputation was not used.t test for continuous variables. Multivariable logistic regression was performed to determine the association between AR and ruptured IA. We present both univariate and multivariate models. In the multivariate model, we included those variables that showed statistical differences between the two groups.Continuous variables are presented as mean (SD) and categorical variables as No. (%). Differences between the unruptured and ruptured groups were evaluated using chi-square test for categorical variables and using We also test the possibility of a non-linear relation of AR with ruptured IA. By the recurrence method, we calculated the inflection points of the U-shaped curve. Afterward, by the two-piecewise linear regression model, we divided the U-shaped curve according to the inflection point, and established the two-piecewise linear model on both sides of the inflection points, and calculated the OR and confidence intervals, respectively.http://www.R-project.org, The R Foundation) and EmpowerStats . P < 0.05 (two-sided) were considered statistically significant.All the analyses were performed with the statistical software packages R (n = 663). At baseline, the mean age of participants was 59.69 years, and the proportion of men was 40.0%. P > 0.05). The ruptured group contained more patients who were older and had larger IA size, mean neck diameter, and comorbidity, more likely to be located in AcoA, PcoA, or MCA compared with patients with unruptured IA. In terms of morphological parameters, those in the ruptured group had lower SR, with a higher proportion of irregular shape, wide neck, and CMBs compared with the unruptured group.The overall prevalence of ruptured IA was 41.75% , including 663 patients with ruptured IA. The U-shaped relationship was seen here for AR with IA rupture. Interestingly, the non-linearity analysis by the two-piecewise linear model demonstrated here captures more variation than a single-slope logistic regression model: AR appears to follow a different pattern of association with ruptured IA in different ranges.In this study, we analyzed the relationship of AR with the prevalence of ruptured IA in a large sample set (Previous studies focused only on the “linear” relationship and yielded conflicting results. Twelve studies (sample size ranging from 8 to 425) and two systematic reviews  found a positive correlation between AR and IA rupture –36. EighGreving et al.  pooled fWe also found that patients with concurrent cerebral microbleeds or irregular IA are associated with a high risk of aneurysm rupture. This is consistent with the previously published literature. Two studies , 45 haveTo investigate how these indicators could influence the differing impact of AR on bleeding risk, we conducted a series of sensitivity analyses. First, when we stratified by age , we found that the relationship between AR and IA bleeding risk is still a U-shaped relationship in patients older than 60 years . SimilarGiven that AR is the ratio of the greatest perpendicular height (IA size) to the mean neck diameter, we also evaluated the association between IA size and mean neck diameter and aneurysm rupture, respectively in this study. We observed a positive association between IA size and IA rupture. This is the same as the previous results. These studies found that the unruptured IAs were significantly smaller than the maximum size of ruptured IAs, and the presence of an unruptured IA of ≥7 mm was an independent risk factor for the lifetime occurrence of SAH , 47. We This research has several strengths of note. First, the sample size of this study is large, ensuring sufficient statistical power. Second, a case-control study design was not used in this study. Compared with previous studies, therefore, the selection bias is reduced. Third, compared to most previous studies that only adjust morphological parameters or demographic characteristics, the adjustment strategy of this study is sufficient and more complete. Fourth, to our best knowledge, it is first to address non-linearity and test interaction on the association of AR with IA rupture. Fifth, sensitivity analysis ensures the robustness of our findings. It roughly explains why the U-shaped relationship between AR and aneurysm rupture can be observed in this study.Indeed, the interpretation of the findings of this study should be cautious. Several limitations are also noteworthy. First, we only include patients who have clinical symptoms to see a doctor. Therefore, the absence of patients without symptoms will result in selection bias. But such patients are non-ruptured IA, therefore, this would have biased results toward the null. Second, conclusions can be generalized to patients with single IA only, and the correlation of AR and ruptured IA may be different in multiple IA. Third, this study was designed for cross-section, so the causal association between AR and IA rupture could not be confirmed because there is no evidence that the morphological parameters before and after IA rupture are unchanged. Fourth, although we have adjusted for those of measurable confounders, as in all observational studies, there might have been still uncontrolled confounding due to unmeasured differences between IA with and without rupture.The independent correlation between AR and ruptured IA is U-shaped. When clinically using AR to estimate the risk of IA bleeding, the different trends within different AR ranges should be judged, especially for the elderly or non-smokers. In addition, older, a history of hypertension, current smoker, large-size IA, located in MCA are independent risk factors for aneurysm rupture. Neurosurgeons can make more detailed and individualized clinical decisions for patients with aneurysms based on these characteristics.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by Ethics Committee of Zhujiang Hospital. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.J-HY wrote the manuscript. S-XS is responsible for data analysis. XZ is responsible for study design and data analysis. Y-MB is responsible for data collection. C-ZD is responsible for the revision of the paper. W-mH and X-LW are responsible for data collection. All authors contributed to the article and approved the submitted version.This work was supported by the National Natural Science Foundation Project (Grant Number: 81974177) and Initiation Plan Project of Clinical Research of Southern Medical University (Grant Number: QD2018N022).The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.