The timing and development of infections in a fish-cestode host-parasite system.

The cestode Schistocephalus solidus is a common parasite in freshwater threespine stickleback populations, imposing strong fitness costs on their hosts. Given this, it is surprising how little is known about the timing and development of infections in natural stickleback populations. Previous work showed that young-of-year stickleback can get infected shortly after hatching. We extended this observation by comparing infection prevalence of young-of-year stickleback from 3 Alaskan populations (Walby, Cornelius and Wolf lakes) over 2 successive cohorts (2018/19 and 2019/20). We observed strong variation between sampling years (2018 vs 2019 vs 2020), stickleback age groups (young-of-year vs 1-year-old) and sampling populations.

Replicated evolutionary inhibition of a complex ancestral behaviour in an adaptive radiation.

Adaptive radiations often exhibit high levels of phenotypic replication, a phenomenon that can be explained by selection on standing variation in repeatedly divergent environments or by the influence of ancestral plasticity on selection in divergent environments. Here, we offer the first evidence that plastic loss of expression of a complex display in a novel environment, followed by selection against expression, could lead to replicated evolutionary inhibition of the phenotype. In both ancestral (oceanic) and benthic (freshwater) populations of the threespine stickleback fish, cannibalism is common and males defending nests respond to approaching groups with a complex diversionary display. This display is not exhibited by males in allopatric, limnetic (freshwater) populations from which cannibalistic groups are absent. Laboratory-reared males from three limnetic populations exhibit a reduced tendency to respond to cannibalistic foraging groups relative to laboratory-reared ancestral and benthic males, but still are capable of producing a similar array of forms of the display despite many generations of disuse. Thus, replication in adaptive radiations can reflect reduced expression of an ancestral trait followed by evolutionary inhibition while the population retains the capacity to express the trait under extreme ancestral conditions.

Evolution of steroid hormones in reproductive females of the threespine stickleback fish.

Hormones play a prominent role in animal development, mediating the expression of traits and coordinating phenotypic responses to the environment. Their role as physiological integrators has implications for how populations respond to natural selection and can impact the speed and direction of evolutionary change. However, many emerging and established fish models with the potential to be ecologically or evolutionarily informative are small-bodied, making hormone sampling through traditional methods (whole-body or plasma) lethal or highly disruptive. Sampling methodology has thus restricted study design, often limiting sample sizes, and has prevented the study of at-risk/endangered populations. We utilize water-borne hormone sampling, a minimally invasive method of measuring the rate of steroid hormone release across the gills and further validate this method in a novel, evolutionary context. First, we compare water-borne hormone measures of cortisol with those quantified from plasma and whole-body samples collected from the same individuals to establish the relationship between concentrations quantified via the three methods. We then compare the release of steroid hormones in three populations of threespine stickleback to establish the sensitivity of this tool in measuring within-individual and between-individual variation in biologically relevant contexts (reproductive stages), and in assessing differences among populations with distinct evolutionary histories. We demonstrate a strong positive relationship between cortisol concentrations measured with water-borne, plasma, and whole-body collection techniques. Tracking estradiol and testosterone throughout clutch production in females produced anticipated patterns associated with growing and maturing eggs, with divergence in estradiol production in one population. Additionally, differences among populations in cortisol levels at ovulation paralleled the relative presence of a social stressor, and thus expected energetic needs within each population. We confirm that water-borne hormone sampling is sufficiently sensitive to capture biologically relevant fluctuations in steroid hormones between environmental contexts and demonstrate that among-population differences are detectable. This technique can be applied broadly to small fish to answer important ecological and evolutionary questions. By linking population variation in hormones and the multivariate phenotype, this technique will help elucidate both proximate mechanisms underlying phenotypic development and variation, and the way hormone networks alter evolutionary responses to selection.

ED Triage Decision-Making With Mental Health Presentations: A "Think Aloud" Study.

INTRODUCTION: Triage is the process whereby persons presenting to the emergency department are quickly assessed by a nurse and their need for care and service is prioritized. Research examining the care of persons presenting to emergency departments with psychiatric and mental health problems has shown that triage has often been cited as the most problematic aspect of the encounter. Three questions guided this investigation: Where do the decisions that triage nurses make fall on the intuitive versus analytic dimensions of decision making for mental health presentations in the emergency department, and does this differ according to comfort or familiarity with the type of mental health/illness presentation? How do "decision aids" (i.e., structured triage scales) help in the decision-making process? To what extent do other factors, such as attitudes, influence triage nurses' decision making? METHODS: Eleven triage nurses participating in this study were asked to talk out loud about the reasoning process they would engage in while triaging patients in 5 scenarios based on mental health presentations to the emergency department. RESULTS: Themes emerging from the data were tweaking the results (including the use of intuition and early judgments) to arrive at the desired triage score; consideration of the current ED environment; managing uncertainty and risk (including the consideration of physical reasons for presentation); and confidence in communicating with patients in distress and managing their own emotive reactions to the scenario. DISCUSSION: Findings support the preference for using the intuitive mode of decision making with only tacit reliance on the decision aid.

Fecundity compensation and fecundity reduction among populations of the three-spined stickleback infected by Schistocephalus solidus in Alaska.

We surveyed nine populations of the three-spined stickleback infected by the diphyllobothriidean cestode Schistocephalus solidus from south-central Alaska for two apparent forms of tolerance to infection in females capable of producing egg clutches notwithstanding large parasite burdens. Seven populations exhibited fecundity reduction, whereas two populations showed fecundity compensation. Our data suggest that fecundity reduction, a side effect resulting from nutrient theft, occurs in two phases of host response influenced by the parasite : host body mass (BM) ratio. The first is significantly reduced ovum mass without significant reduction in clutch size, and the second one involves significant reductions in both ovum mass and clutch size. Thus, ovum mass of host females who are functionally being starved through nutrient theft seems to be more readily influenced by parasitism and, therefore, decreased before clutch size is reduced. This inference is consistent with expectations based on the biology of and effect of feeding ration on reproduction in stickleback females. Fecundity compensation appears to be uncommon among populations of three-spined stickleback in Alaska and rare among populations throughout the northern hemisphere. Fecundity reduction seems to be common, at least among stickleback populations in Alaska.

Effects of predation risk on egg steroid profiles across multiple populations of threespine stickleback.

Predation often has consistent effects on prey behavior and morphology, but whether the physiological mechanisms underlying these effects show similarly consistent patterns across different populations remains an open question. In vertebrates, predation risk activates the hypothalamic-pituitary-adrenal (HPA) axis, and there is growing evidence that activation of the maternal HPA axis can have intergenerational consequences via, for example, maternally-derived steroids in eggs. Here, we investigated how predation risk affects a suite of maternally-derived steroids in threespine stickleback eggs across nine Alaskan lakes that vary in whether predatory trout are absent, native, or have been stocked within the last 25 years. Using liquid chromatography coupled with mass spectroscopy (LC-MS/MS), we detected 20 steroids within unfertilized eggs. Factor analysis suggests that steroids covary within and across steroid classes (i.e. glucocorticoids, progestogens, sex steroids), emphasizing the modularity and interconnectedness of the endocrine response. Surprisingly, egg steroid profiles were not significantly associated with predator regime, although they were more variable when predators were absent compared to when predators were present, with either native or stocked trout. Despite being the most abundant steroid, cortisol was not consistently associated with predation regime. Thus, while predators can affect steroids in adults, including mothers, the link between maternal stress and embryonic development is more complex than a simple one-to-one relationship between the population-level predation risk experienced by mothers and the steroids mothers transfer to their eggs.

Clinical decision-making for 'as needed' medications in mental health care.

AIM: This paper is a report of a study exploring the medical and nursing decision-making process associated with the prescription and administration of 'as needed' psychotropic medication. BACKGROUND: The administration of 'as needed' psychotropic medications is a relatively autonomous component of a nurse's role, allowing for the capacity to administer psychotropic medications rapidly in acute situations or at the request of a patient. From the research evidence available to date, it is very difficult to determine how doctors and nurses make decisions about the prescription and administration of 'as needed' psychotropic medications. METHOD: A qualitative exploratory-descriptive study was undertaken to explore nurses and doctors decision-making surrounding the administration of pro re nata or 'as needed' psychotropic medications. Nineteen medical and nursing staff from three mental healthcare sites (acute, secure and rehabilitation) in Australia participated in semi-structured interviews in 2006. Thematic content analysis of the transcripts was conducted independently by two members of the research team and then merged to form the final themes. RESULTS: Four themes were identified in the data: decision-making processes; factors which influenced the administration and prescription of 'as needed' medication; individual protocols and improving practice. CONCLUSION: In-service education should be developed for mental health nurses on psychotropic medications and 'as needed' medications, and on the appropriate use of 'as needed' medications as a behaviour management strategy. Further, an extensive review of 'as needed' medication prescription and administration compared to best practice guidelines is needed.

The relationship between workforce characteristics and perception of quality of care in mental health: A qualitative study.

BACKGROUND: Mental health services worldwide are under strain from a combination of unprecedented demand, workforce reconfigurations, and government austerity measures. There has been relatively little research or policy focus on the impact of staffing and skill mix on safety and quality in mental health services leaving a considerable evidence gap. Given that workforce is the primary therapeutic intervention in secondary mental health care this constitutes a major deficit. OBJECTIVE: This study aimed to explore the impact of staffing and skill mix on safety and quality of care in mental health inpatient and community services. DESIGN: Exploratory, qualitative methodology; purposive sampling. SETTINGS: Inpatient and community mental health services in the United Kingdom. PARTICIPANTS: 21 staff (including nurses, occupational therapists, psychiatrists, social workers, and care co-ordinators) currently working in mental health services. METHODS: We conducted semi-structured telephone interviews with a purposive sample of staff recruited via social media. We asked participants to describe the staffing and skill mix in their service; to reflect on how staffing decisions and/or policy affected safety and patient care; and for their views of what a well-staffed ward/service would look like. We conducted thematic analysis of the interview transcripts. RESULTS: The participants in this study considered safestaffing to require more than having 'enough' staff and offered multiple explanations of how staffing and skill mix can impact on the safety and quality of mental health care. From their accounts, we identified how the problem of 'understaffing' is self-perpetuating and cyclical and how its features interact and culminate in unsafe care. We conceptualised the relationship between staffing and safety as a 'vicious cycle of unsafestaffing' which comprised: (1) understaffing (the depletion of resources for safe care provision); (2) chronic understaffing (conditions resulting from and exacerbating understaffing); and, (3) unsafestaffing (the qualities of staffing that compromise staff capacity to provide safe care). CONCLUSIONS: Continued policy focus on safestaffing is clearly warranted, especially in mental health as staffing constitutes both the principal cost and main therapeutic driver of care. This paper provides compelling reasons to look beyond regulating staff numbers alone, and to consider staff morale, burden and the cyclical nature of attrition to ensure the delivery of high quality, safe and effective services. Future research should investigate other mechanisms via which staffing impacts on safety in mental health settings.

A test of the "flexible stem" model of evolution: ancestral plasticity, genetic accommodation, and morphological divergence in the threespine stickleback radiation.

If an ancestral stem group repeatedly colonizes similar environments, developmental plasticity specific to that group should consistently give rise to similar phenotypes. Parallel selection on those similar phenotypes could lead to the repeated evolution of characteristic ecotypes, a property common to many adaptive radiations. A key prediction of this "flexible stem" model of adaptive radiation is that patterns of phenotypic divergence in derived groups should mirror patterns of developmental plasticity in their common ancestor. The threespine stickleback radiation provides an excellent opportunity to test this prediction because the marine form is representative of the ancestral stem group, which has repeatedly given rise to several characteristic ecotypes. We examined plasticity of several aspects of shape and trophic morphology in response to diets characteristic of either the derived benthic ecotype or the limnetic ecotype. When marine fish were reared on alternative diets, plasticity of head and mouth shape paralleled phenotypic divergence between the derived ecotypes, supporting the flexible stem model. Benthic and limnetic fish exhibited patterns of plasticity similar to those of the marine population; however, some differences in population means were present, as well as subtle differences in shape plasticity in the benthic population, indicating a role for genetic accommodation in this system.

A best-evidence synthesis review of the administration of psychotropic pro re nata (PRN) medication in in-patient mental health settings.

AIMS AND OBJECTIVES: This paper aims to synthesise published literature of drug use/administration studies of pro re nata psychotropic medications in mental health wards. DESIGN: The study employed a best-evidence synthesis review design. BACKGROUND: The administration of psychotropic pro re nata medications is a frequently used clinical intervention in mental health wards. Pro re nata contributes to exposing patients to high doses of antipsychotic medication. Despite the frequent use of pro re nata, there is limited evidence of their effectiveness. METHODS: A best-evidence synthesis review. RESULTS: Six major themes emerged from the literature: (i) frequency of administration; (ii) administration during the 24-hour day; (iii) administration associated with length and stage of admission; (iv) rationales for administration; (v) medicines administered (including route of administration); and (vi) effects and side effects of the medicines administered. CONCLUSIONS: Overall findings indicate that the administration of psychotropic pro re nata varies radically and appears to be influenced by many variables. Relevance to clinical practice. Patients are most likely to receive a benzodiazepine or typical antipsychotic as pro re nata. Pro re nata is an important and under-researched clinical intervention used in mental health wards.

Exploration of therapeutic interventions that accompany the administration of p.r.n. ('as required') psychotropic medication within acute mental health settings: a retrospective study.

Within acute mental health settings, pro re nata (p.r.n.) 'as required' medication is a widely used adjunct to regular treatment plans, and is administered at the discretion of a registered nurse. However, there is concern that some orders may benefit staff more than patients by providing a 'quick fix' to compensate for inadequate therapeutic programmes. Previous authors assert that p.r.n. medication administration should not be the first line of action, but should be used when other less invasive interventions such as de-escalation, talking, or separation from the group are unsuccessful. This project explored the occurrence of p.r.n. medication administration and the type of alternative therapeutic interventions that are documented as accompanying its administration. A retrospective 1-month chart audit was undertaken for a cohort of inpatients in a 20-bed mental health facility attached to a regional hospital in New South Wales, Australia. Forty-seven patients (73.4%) received p.r.n. medication at least once, with a total of 309 doses of p.r.n. medication administered during this time. There were wide variations in the documented rationales, and for nearly three-quarters (73%) of p.r.n. medication administrations, no other therapeutic intervention was documented as occurring prior to administration.

Cognitive behaviour therapy within acute mental health care: a critical appraisal.

This paper examines the evidence for the use of cognitive behavioural therapy (CBT) within acute mental health-care settings. Through the provision of a literature review the authors critique the research into the effectiveness of CBT when delivered within acute mental health-care settings, to clients who are acutely psychotic. The review concludes with recommendations for future research to expand the current evidence base.

Evolutionary Influences of Plastic Behavioral Responses Upon Environmental Challenges in an Adaptive Radiation.

At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of responses to environmental modification. Our work offers insights into the complexity of cognitive responses to environmental change, and into the importance of examining multiple aspects of the phenotype simultaneously, if we are to understand how behavioral shifts contribute to the persistence of populations and to subsequent evolution. We conclude by discussing the origins of apparent novelties induced by environmental shifts, and the importance of accounting for geographic variation within species if we are to accurately anticipate the effects of anthropogenic environmental modification on the persistence and evolution of animals.

The evolution of antipredator behaviour following relaxed and reversed selection in Alaskan threespine stickleback fish.

Changing environments, whether through natural or anthropogenic causes, can lead to the loss of some selective pressures ('relaxed selection') and possibly even the reinstatement of selective agents not encountered for many generations ('reversed selection'). We examined the outcome of relaxed and reversed selection in the adaptive radiation of the threespine stickleback fish, Gasterostues aculeatus L., in which isolated populations encounter a variety of predation regimes. Oceanic stickleback, which represent the ancestral founders of the freshwater radiation, encounter many piscivorous fish. Derived, freshwater populations, on the other hand, vary with respect to the presence of predators. Some populations encounter native salmonids, whereas others have not experienced predation by large fish in thousands of generations (relax-selected populations). Some relax-selected populations have had sport fish, including rainbow trout, Oncorhynchus mykiss, introduced within the past several decades (reverse-selected). We examined the behavioural responses of stickleback from three populations of each type to simulated attacks by trout and birds to determine whether relaxed and reversed selection has led to divergence in behaviour, and whether this divergence was predator specific. Fish from trout-free populations showed weak responses to trout, as predicted, but these responses were similar to those of oceanic (ancestral) populations. Fish from populations that co-occur with trout, whether native or introduced, showed elevated antipredator responses, indicating that in freshwater, trout predation selects for enhanced antipredator responses, which can evolve extremely rapidly. Comparison of laboratory-reared and wild-caught individuals suggests a combination of learned and genetic components to this variation. Responses to a model bird flyover were weakly linked to predation environment, indicating that the loss of predation by trout may partially influence the evolution of responses to birds. Our results reject the hypothesis that the consistent presence of predatory birds has been sufficient to maintain responses to piscivorous fish under periods of relaxed selection.

Reduction of egg size in natural populations of threespine stickleback infected with a cestode macroparasite.

Manifestations of infectious disease may represent host adaptations to avoid or reduce the effects of infection on host fitness, parasite manipulations that benefit the pathogen's fitness, or nonadaptive side effects of parasitism. Threespine stickleback fish (Gasterosteus aculeatus) from Alaska and the cestode macroparasite Schistocephalus solidus provide an excellent system for study of the effects of parasitism on host egg size because females in populations there are capable of producing clutches of eggs in the face of substantial infection, contrary to the inhibition of reproduction that has been observed in other stickleback populations or other species of fish. A side effect resulting in reduction of mean ovummass among infected females was predicted based on the egg production process in female stickleback, the considerable energy and resource demands of S. solidus, and the chronic and progressive nature of the effects the macroparasite should have on the host fish. In each of 9 populations of G. aculeatus representing replicate natural experiments in lakes scattered across the Matanuska-Susitna Valley and the Kenai Peninsula of south-central Alaska and among all populations combined, the mean ovum mass of infected female fish is significantly reduced in comparison with that of uninfected females taken from the same population at the same time. Reduction in mean female egg mass ranged from 8 to 32% across all populations. To examine whether reduction in mean female ovum mass was a nonadaptive side effect or an adaptation, relatively large data sets from 2 of the populations were used. Mean ovum mass of infected females was predicted to decrease directly in relation to parasite index (PI) if the diminution in mean egg mass were the result of a nonadaptive side effect resulting from host nutrient loss. Alternatively, the absence of a relationship between PI and reduction in ovum mass is predicted if decreases in mean female ovum mass result from host or parasite adaptation (or both) because lightly infected hosts should show a response similar to that of heavily infected ones. In each of the 2 populations, there is a significant, negative relationship between mean female ovum mass and PI, demonstrating a correlation between the decrease in ovum mass and the level of infection. Thus, the results are consistent with the hypothesis that the reductions in mean female egg mass represent side effects of parasitism involving nutrient theft. Moreover, the proportional decline in egg mass with increasing PI apparently differed between the 2 populations, and there was no significant relationship between mean percent decrease in mean female ovum mass and mean PI across populations. These observations suggest that unknown ecological and evolutionary factors influence the degree of reduction in mean ovum mass in a population-specific manner.

The "crowding effect" in the cestode Schistocephalus solidus: density-dependent effects on plerocercoid size and infectivity.

The occurrence of the crowding effect was demonstrated in plerocercoids of the cestode Schistocephalus solidus infecting threespine stickleback Gasterosteus aculeatus from Walby and Scout lakes, Alaska. Contrary to an earlier report, relatively large numbers of parasites (>3-4 plerocercoids) were observed to grow large enough in an intermediate host fish to become competent to infect and to mature in the definitive host under any of 3 assumed threshold values and 1 scenario of graded sizes for parasite competency. In Walby Lake, intensity and host body mass were significant predictors of mean plerocercoid mass per host, whereas intensity, host body mass, and combined parasite index were significant predictors in Scout Lake. Slopes of equations expressing the relationship between mean parasite mass and intensity for both lakes were less than 1, implying that processes other than or in combination with simple resource limitation might be producing the observed crowding effect. The causal mechanism for the crowding effect could include exploitative competition, interference competition, and host immune response. There were significant differences in infection between the two lakes, including different distributions of parasite intensities among hosts and different expressions of the crowding effect; however, an explanation of the differences awaits further investigation.

The prevalence of asymptomatic Chlamydia trachomatis in military dependent adolescents.

Chlamydia trachomatis infection is common among sexually active populations and often asymptomatic. Infection is associated with complications, including pelvic inflammatory disease and infertility. Using a noninvasive urine ligase chain reaction assay, we determined the prevalence of asymptomatic C. trachomatis infection among sexually active military dependent adolescents and young adults attending clinics at military facilities in San Antonio. The overall prevalence rate was 14%, higher than that reported in many high-risk settings, including sexually transmitted disease clinics. Gender-specific rates were 15% for females and 11% for males. Given a clear cost benefit to screening and treating at-risk populations, we conclude that screening of all sexually active military dependents, both male and female, using this noninvasive test should be performed routinely.

Accelerating electrostatic pair methods on graphical processing units to study molecules in supercritical carbon dioxide.

Traditionally, electrostatic interactions are modelled using Ewald techniques, which provide a good approximation, but are poorly suited to GPU architectures. We use the GPU versions of the LAMMPS MD package to implement and assess the Wolf summation method. We compute transport and structural properties of pure carbon dioxide and mixtures of carbon dioxide with either methane or difluoromethane. The diffusion of pure carbon dioxide is indistinguishable when using the Wolf summation method instead of PPPM on GPUs. The optimum value of the potential damping parameter, α, is 0.075. We observe a decrease in accuracy when the system polarity increases, yet the method is robust for mildly polar systems. We anticipate the method can be used for a number of techniques, and applied to a variety of systems. Substitution of PPPM can yield a two-fold decrease in the wall-clock time.

Ancestral Plasticity and Allometry in Threespine Stickleback Fish Reveal Phenotypes Associated with Derived, Freshwater Ecotypes.

For over a century, evolutionary biologists have debated whether and how phenotypic plasticity impacts the processes of adaptation and diversification. The empirical tests required to resolve these issues have proven elusive, mainly because it requires documentation of ancestral reaction norms, a difficult prospect where many ancestors are either extinct or have evolved. The threespine stickleback radiation is not limited in this regard, making it an ideal system in which to address general questions regarding the role of plasticity in adaptive evolution. As retreating ice sheets have exposed new habitats, oceanic stickleback founded innumerable freshwater populations, many of which have evolved parallel adaptations to their new environments. Because the founding oceanic population is extant, we can directly evaluate whether specific patterns of ancestral phenotypic expression in the context of novel environments (plasticity), or over ontogeny, predisposed the repeated evolution of "benthic" and "limnetic" ecotypes in shallow and deep lakes, respectively. Consistent with this hypothesis, we found that oceanic stickleback raised in a complex habitat and fed a macroinvertebrate diet expressed traits resembling derived, benthic fish. Alternatively, when reared in a simple environment on a diet of zooplankton, oceanic stickleback developed phenotypes resembling derived, limnetic fish. As fish in both treatments grew, their body depths increased allometrically, as did the size of their mouths, while their eyes became relatively smaller. Allometric trajectories were subtly but significantly impacted by rearing environment. Thus, both environmental and allometric influences on development, along with their interactive effects, produced variation in phenotypes consistent with derived benthic and limnetic fish, which may have predisposed the repeated genetic accommodation of this specific suite of traits. We also found significant shape differences between marine and anadromous stickleback, which has implications for evaluating the ancestral state of stickleback traits.