Estimating Density Dependence, Environmental Variance, and Long-Term Selection on a Stage-Structured Life History.

AbstractA method for analyzing long-term demographic data on density-dependent stage-structured populations in a stochastic environment is derived to facilitate comparison of populations and species with different life histories. We assume that a weighted sum of stage abundances, N, exerts density dependence on stage-specific vital rates of survival and reproduction and that N has a small or moderate coefficient of variation. The dynamics of N are approximated as a univariate stochastic process governed by three key parameters: the density-independent growth rate, the net density dependence, and environmental variance in the life history. We show how to estimate the relative weighs of stages in N and the key parameters. Life history evolution represents a stochastic maximization of a simple function of the key parameters. The long-term selection gradient on the life history can be expressed as a vector of sensitivities of this function with respect to density-independent, density-dependent, and stochastic components of the vital rates. To illustrate the method, we analyze 38 years of demographic data on a great tit population, estimating the key parameters, which accurately predict the observed mean, coefficient of variation, and fluctuation rate of N; we also evaluate the long-term selection gradient on the life history.

Toll-like receptors in mediating pathogenesis in systemic sclerosis.

Toll-like receptors (TLRs) are evolutionarily conserved receptors essential for the host defence against pathogens. Both immune and non-immune cells can express TLRs, although at different levels. Systemic sclerosis (SSc) is a chronic disease in which autoimmunity, dysregulated profibrotic mediator release and activation of fibroblasts lead to dysregulated collagen deposition and fibrosis. There is now increasing knowledge that the innate immune system and, in particular, TLRs take a part in SSc pathogenesis. The list of endogenous ligands that can stimulate TLRs in SSc is growing: these ligands represent specific danger-associated molecular patterns (DAMPs), involved either in the initiation or the perpetuation of inflammation, and in the release of factors that sustain the fibrotic process or directly stimulate the cells that produce collagen and the endothelial cells. This review reports evidences concerning TLR signalling involvement in SSc. We report the new DAMPs, as well as the TLR-linked pathways involved in disease, with emphasis on type I interferon signature in SSc, the role of plasmacytoid dendritic cells (pDCs) and platelets. The dissection of the contribution of all these pathways to disease, and their correlation with the disease status, as well as their values as prognostic tools, can help to plan timely intervention and design new drugs for more appropriate therapeutic strategies.

American Civil War medical practice, the post-bellum opium crisis and modern comparisons.

The American Civil War resulted in massive numbers of injured and ill soldiers. Throughout the conflict, medical doctors relied on opium to treat these conditions, giving rise to claims that the injudicious use of the narcotic caused America's post-bellum opium crisis. Similar claims of medical misuse of opioids are now made as America confronts the modern narcotic crisis. A more nuanced thesis based on a broader base of Civil War era research suggests a more complex set of interacting factors that collectively contributed to America's post-war opium crisis.

Adaptive behavior impaired in children with low-grade glioma.

BACKGROUND: Adaptive behavior, i.e., the performance on daily activities required for personal and social independence, is essential to estimate in children with low-grade glioma (LGG) since most of them are long-term survivors. Our aim was to investigate adaptive behavior in children with LGG. METHODS: In a cross-sectional study, adaptive behavior was assessed using the paper pencil version of the Parent Form of the Vineland Adaptive Behavior Scales 2nd edition (VABS-II) testing communication, daily living skills, social skills, and motor skills. Scores of children with LGG, younger than 20 years, and diagnosed between 2004 and 2014 were compared with family controls. Correlations between clinical variables and adaptive behavior were explored. RESULTS: Fifty-six children with LGG (median age, 12.1 years; 52% male) and 46 controls (median age, 11.0 years; 43% male) were included in the analyses. Compared with controls, the LGG group was more impaired on total adaptive behavior, communication, and motor skills and in the subdomain gross motor skills (effect sizes d, 0.64-0.86, P < 0.003). Younger age at diagnosis (r = -0.357, P < 0.01) and chemotherapy (r = -0.342, P < 0.05) were associated with poorer motor skills. Residual disease was associated with poorer total adaptive behavior (r = -0.282, P < 0.05). No other significant correlations were found. CONCLUSION: At the group level, adaptive functioning of children with LGG is impaired compared with family controls. Regular structured monitoring of adaptive behavior is recommended to be able to define the needs for tailored rehabilitation in daily life at home as well as at school.

Alcohol Biomarkers Associated with Obstructive Sleep Apnea.

The views expressed in this presentation are those of the author and do not reflect the official policy of the Department of the Army/Navy/Air Force or the Department of Defense The identification of specific products or scientific instrumentation does not constitute an endorsement or implied endorsement on the part of the authors, DoD, or any component agency. While we generally excise references to products, companies, manufacturers, organizations, etc. in government produced works, the abstracts produced and other similarly situated researchers presents a special circumstance when such product inclusions become an integral part of the scientific endeavor.

Evolution of phenotypic plasticity and environmental tolerance of a labile quantitative character in a fluctuating environment.

Quantitative genetic models of evolution of phenotypic plasticity are used to derive environmental tolerance curves for a population in a changing environment, providing a theoretical foundation for integrating physiological and community ecology with evolutionary genetics of plasticity and norms of reaction. Plasticity is modelled for a labile quantitative character undergoing continuous reversible development and selection in a fluctuating environment. If there is no cost of plasticity, a labile character evolves expected plasticity equalling the slope of the optimal phenotype as a function of the environment. This contrasts with previous theory for plasticity influenced by the environment at a critical stage of early development determining a constant adult phenotype on which selection acts, for which the expected plasticity is reduced by the environmental predictability over the discrete time lag between development and selection. With a cost of plasticity in a labile character, the expected plasticity depends on the cost and on the environmental variance and predictability averaged over the continuous developmental time lag. Environmental tolerance curves derived from this model confirm traditional assumptions in physiological ecology and provide new insights. Tolerance curve width increases with larger environmental variance, but can only evolve within a limited range. The strength of the trade-off between tolerance curve height and width depends on the cost of plasticity. Asymmetric tolerance curves caused by male sterility at high temperature are illustrated. A simple condition is given for a large transient increase in plasticity and tolerance curve width following a sudden change in average environment.

Prevalence and characteristics of military malingering.

The authors' principle objective was determining the prevalence and characteristics of medical malingering in the military. The authors accessed an electronic database used by the Department of Defense to monitor and manage military health care activities worldwide. The authors searched the database from 2006 to 2011 in the Northern Regional Medical Command for all instances where a health care provider, consequent to an outpatient medical visit, diagnosed malingering, factitious disorder with psychological symptoms, or factitious disorder with physical symptoms. During the time period studied, the Northern Regional Medical Command reported 28,065,568 health care visits. During the same time period, clinicians diagnosed 1,074 individuals with malingering, factitious disorder with predominantly psychological signs and symptoms, or factitious disorder with predominantly physical signs and symptoms. The typical subject diagnosed with one of these disorders was young, male, nonmarried, and enlisted. Although most diagnoses came from a mental health clinic, other medical specialties also contributed to the total tally. These diagnoses are extremely rare based on the findings from this study of outpatient medical care visits.

Adaptation to marginal habitats by evolution of increased phenotypic plasticity.

In an island population receiving immigrants from a larger continental population, gene flow causes maladaptation, decreasing mean fitness and producing continued directional selection to restore the local mean phenotype to its optimum. We show that this causes higher plasticity to evolve on the island than on the continent at migration-selection equilibrium, assuming genetic variation of reaction norms is such that phenotypic variance is higher on the island, where phenotypes are not canalized. For a species distributed continuously in space along an environmental gradient, higher plasticity evolves at the edges of the geographic range, and in environments where phenotypes are not canalized. Constant or evolving partially adaptive plasticity also alleviates maladaptation owing to gene flow in a heterogeneous environment and produces higher mean fitness and larger population size in marginal populations, preventing them from becoming sinks and facilitating invasion of new habitats. Our results shed light on the widely observed involvement of partially adaptive plasticity in phenotypic clines, and on the mechanisms causing geographic variation in plasticity.

Felo De Se: soldier suicides in America's Civil War.

OBJECTIVE: This article examined the factors associated with suicide during America's Civil War and the years immediately following the cessation of armed conflict. METHODS: Contemporary newspaper reports, complemented by book and journal articles, provide an understanding of the incidence and motivations of suicide. RESULTS: The rate of suicide in the general population dramatically increased in the years following the war's end. During the Civil War, suicides occurred nearly every month, reliably peaking in the spring of each year. Depression and alcohol abuse were major factors associated with military suicides. CONCLUSION: Emotional disorders and alcohol misuse, when combined with the hardships of war, contributed to a steady rate of suicides during the Civil War.

Estimating the ratio of effective to actual size of an age-structured population from individual demographic data.

The effective population size is a central concept for understanding evolutionary processes in a finite population. We employ Fisher's reproductive value to estimate the ratio of effective to actual population size for an age-structured population with two sexes using random samples of individual vital rates. The population may be subject to environmental stochasticity affecting the vital rates. When the mean sex ratio at birth is known, improved efficiency is obtained by utilizing the records of total number of offspring rather than considering separately female and male offspring. We also show how to incorporate uncertain paternity.

Nutraceutical Augmentation Strategies for Depression: A Narrative Review.

Context: Depression is one of the most commonly diagnosed psychiatric disorders, but antidepressant pharmacotherapy often fails to achieve remission, leading health care professionals and researchers to consider various augmentation strategies to improve clinical outcomes. Objective: To assess the safety, tolerability, and efficacy of nutraceutical augmentation for depression. Methods: Nutraceutical-focused systematic reviews and clinical practice guidelines identified the more commonly studied augmentation strategies for depression. Results: S-adenosylmethionine, l-methylfolate, omega-3 fatty acids, and hydroxyvitamin D have sufficient scientific evidence to support their clinical consideration in the stepped care approach to the management of depression. Conclusions: Clinical remission is the goal in the management of depression, and nutraceuticals may be part of an overall treatment approach to achieve that outcome.

Native/citrullinated LL37-specific T-cells help autoantibody production in Systemic Lupus Erythematosus.

LL37 exerts a dual pathogenic role in psoriasis. Bound to self-DNA/RNA, LL37 licenses autoreactivity by stimulating plasmacytoid dendritic cells-(pDCs)-Type I interferon (IFN-I) and acts as autoantigen for pathogenic Th17-cells. In systemic lupus erythematosus (SLE), LL37 also triggers IFN-I in pDCs and is target of pathogenic autoantibodies. However, whether LL37 activates T-cells in SLE and how the latter differ from psoriasis LL37-specific T-cells is unknown. Here we found that 45% SLE patients had circulating T-cells strongly responding to LL37, which correlate with anti-LL37 antibodies/disease activity. In contrast to psoriatic Th17-cells, these LL37-specific SLE T-cells displayed a T-follicular helper-(TFH)-like phenotype, with CXCR5/Bcl-6 and IL-21 expression, implicating a role in stimulation of pathogenic autoantibodies. Accordingly, SLE LL37-specific T-cells promoted B-cell secretion of pathogenic anti-LL37 antibodies in vitro. Importantly, we identified abundant citrullinated LL37 (cit-LL37) in SLE tissues (skin and kidney) and observed very pronounced reactivity of LL37-specific SLE T-cells to cit-LL37, compared to native-LL37, which was much more occasional in psoriasis. Thus, in SLE, we identified LL37-specific T-cells with a distinct functional specialization and antigenic specificity. This suggests that autoantigenic specificity is independent from the nature of the autoantigen, but rather relies on the disease-specific milieu driving T-cell subset polarization and autoantigen modifications.

Displacement of flowering phenologies among plant species by competition for generalist pollinators.

We model the evolution of allochronic isolation between sympatric animal-pollinated plant species via displacement of their flowering times. The plant species share generalist pollinators and either produce inviable hybrid seeds or do not hybridize at all. Displacement of flowering times between reproductively isolated species reduces competition for pollinators and the formation of inviable hybrid seeds. Under strong pollen limitation, competition for pollinators causes rapid evolution of allochronic isolation both for hybridizing and nonhybridizing species. Under weak pollen limitation, allochronic isolation evolves rapidly for hybridizing species but more slowly for nonhybridizing species. Positive density-dependent pollinator visitation rate at low flower densities facilitates allochronic isolation under weak pollen limitation. Allochronic isolation among sympatric species sharing generalist pollinators could be common under any intensity of pollen limitation if the flowering season is sufficiently long.

Genetics and demography in biological conservation.

Predicting the extinction of single populations or species requires ecological and evolutionary information. Primary demographic factors affecting population dynamics include social structure, life history variation caused by environmental fluctuation, dispersal in spatially heterogeneous environments, and local extinction and colonization. In small populations, inbreeding can greatly reduce the average individual fitness, and loss of genetic variability from random genetic drift can diminish future adaptability to a changing environment. Theory and empirical examples suggest that demography is usually of more immediate importance than population genetics in determining the minimum viable sizes of wild populations. The practical need in biological conservation for understanding the interaction of demographic and genetic factors in extinction may provide a focus for fundamental advances at the interface of ecology and evolution.

Adaptive topography of fluctuating selection in a Mendelian population.

An adaptive topography is derived for a large randomly mating diploid population under weak density-independent selection in a fluctuating environment. Assuming a stationary distribution of environmental states with no temporal autocorrelation, a diffusion approximation for population size and allele frequency, p, reveals that the expected change in p involves the gradient with respect to p of the stochastic intrinsic rate of increase (the density-independent long-run growth rate), r = r - sigma 2 e/2, where r is the mean Malthusian fitness in the average environment and is the environmental variance in population growth rate. The expected relative fitness of a genotype is its Malthusian fitness in the average environment minus the covariance of its fitness with population growth rate. The influence of fitness correlation between genotypes is illustrated by an analysis of the Haldane-Jayakar model of fluctuating selection on a single diallelic locus, and on two loci with additive effects on a quantitative character.

Survey of alcohol use in the U.S. Army.

The objective of this study was to collect data that would provide information about the frequency, attitudes, and consequences of alcohol use in the U.S. Army. A questionnaire was used to assess the frequency of alcohol consumption, attitudes related to the use of alcohol, and adverse consequences experienced with alcohol use. The survey was conducted at Walter Reed Army Medical Center in Washington, D.C. Survey participants included both military employees working at Walter Reed Army Medical Center and military patients. No attempt was made to identify the medical status of the participants. The investigators distributed 1,200 questionnaires. Following distribution, the investigators received 1,010 completed questionnaires, resulting in an 84% return rate. Thirty-four percent of the survey participants (n = 335) were deployed to an area of combat operations. There was a significant difference in binge drinking between military personnel assigned to an area of combat operations and those not assigned to an area of combat operations (p = 0.023). Multiple regression results showed that age, marital status, and deployment status were correlated with four or more drinks at one time (p < 0.001). In other words, binge drinking is more likely to occur among military personnel who are younger, experiencing marital problems, and recently returned from an area of combat operations. Significant differences between the two groups also emerged in terms of other specific consequences associated with consumption. Deployment to an area of combat operations seems to influence consumption patterns, alcohol related attitudes, and behaviors. This could be a consequence of wartime experiences. This study should help guide the clinical screening of alcohol use disorders, which may complicate emotional recovery from traumatic experiences if undetected.

Invalid corps.

OBJECTIVES: This article explores America's historical experience with medical disability compensation programs during the Revolutionary War and the Civil War. METHODS: Contemporary newspaper reports, complemented by book and journal articles, provide an understanding of the medical disability compensation programs offered during the Revolutionary War and the Civil War. RESULTS: Military planners, politicians, and service members struggled to develop a fair and balanced medical disability compensation program during the Revolutionary War and the Civil War. CONCLUSIONS: Based on America's extensive experience with the Civil War Invalid Corps, an alternative for motivated military personnel could be developed.

Prospective Study of Brain Wave Changes Associated With Cranial Electrotherapy Stimulation.

OBJECTIVE: To explore brain wave changes associated with cranial electrotherapy stimulation (CES) among subjects receiving psychiatric care. METHODS: Quantitative electroencephalogram data were obtained before and after a 20-minute session of CES. The investigators recruited active-duty military subjects from Walter Reed National Military Medical Center's Psychiatry Continuity Service, Bethesda, Maryland. Fifty subjects participated in this prospective, convenience sample study from August 2016 through March 2017. The main outcome measures were changes in brain wave activity and the Subjective Units of Distress Scale. RESULTS: The typical subject was mildly depressed and had severe trauma-related symptoms and sleep problems. There was a significant increase (P = .000) in the higher beta frequencies (18-21 Hz, 21-33 Hz, and 33-48 Hz) and a strong effect (with the Cohen d around 1.5) immediately following the 20-minute CES. Ten minutes after CES, slower wave activity (4-8 Hz and 8-12 Hz) significantly decreased (P < .05), while higher beta wave activity (13-15 Hz, 18-21 Hz, and 21-33 Hz) increased. A strong effect (with the Cohen d around 1.5) persisted in the beta brain wave bands 18-21 Hz and 21-33 Hz. CONCLUSIONS: Brain wave measurements taken immediately after the 20-minute CES session showed a significant and strong effect in the beta region, suggesting an increase in mental alertness, focus, and concentration. Ten minutes after the CES session, an even more marked change in brain wave activity occurred. The significant and strong effect in the beta region persisted but was joined by a reduction in slower wave activity, indicating an increase in mental alertness. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03298308.

The Reasons for Living Scale-Military Version: Assessing Protective Factors Against Suicide in a Military Sample.

INTRODUCTION: Military suicide rates have been rising over the past decade and continue to challenge military treatment facilities. Assessing suicide risk and improving treatments are a large part of the mission for clinicians who work with uniformed service members. This study attempts to expand the toolkit of military suicide prevention by focusing on protective factors over risk factors. In 1983, Marsha Linehan published a checklist called the Reasons for Living Scale, which asked subjects to check the reasons they choose to continue living, rather than choosing suicide. The authors of this article hypothesized that military service members may have different or additional reasons to live which may relate to their military service. They created a new version of Linehan's inventory by adding protective factors related to military life. The purpose of these additions was to make the inventory more acceptable and relevant to the military population, as well as to identify whether these items constitute a separate subscale as distinguished from previously identified factors. MATERIALS AND METHODS: A commonly used assessment tool, the Reasons for Living Inventory (RFL) designed by Marsha Linehan, was expanded to offer items geared to the military population. The RFL presents users with a list of items which may be reasons to not commit suicide (e.g., "I have a responsibility and commitment to my family"). The authors used focus groups of staff and patients in a military psychiatric partial hospitalization program to identify military-centric reasons to live. This process yielded 20 distinct items which were added to Linehan's original list of 48. This expanded list became the Reasons for Living-Military Version. A sample of 200 patients in the military partial hospitalization program completed the inventory at time of or close to admission. This study was approved by the Institutional Review Board at Walter Reed National Military Center for adhering to ethical principles related to pursuing research with human subjects. RESULTS: The rotated factor matrix revealed six factors that have been labeled as follows: Survival and Coping Beliefs, Military Values, Responsibility to Family, Fear of Suicide/Disability/Unknown, Moral Objections and Child-Related Concerns. The subscale of Military Values is a new factor reflecting the addition of military items to the original RFL. CONCLUSIONS: Results suggest that formally assessing protective factors in a military psychiatric population has potential as a useful tool in the prevention of military suicide and therefore warrants further research. The latent factor we have entitled "Military Values" may help identify those service members for whom military training or "esprit de corps" is a reason for living. Further research can focus on further validation, pre/post-treatment effects on scores, expanded clinical use to stimulate increased will to live, or evaluation of whether scores on this scale, or the subscale of Military Values, can predict future suicidal behavior by service members. Finally, a larger sample size may produce more robust results to support these findings.

Components and Characteristics of a Psychiatric Partial Hospital Military Program.

This article describes the components of a psychiatric partial hospital military program and the characteristics of referrals received over the 5-year period from 2009 to 2013. The 5-year study period included ongoing combat operations in Iraq and Afghanistan along with their subsequent troop withdrawals and change in mission. A total of 1,194 service members were referred for this level of care, and even with the changing battlefield conditions, the number of psychiatric referrals remained steady throughout the 5-year period, with a significant spike in admissions in 2013. The principal diagnoses were major depressive disorder and post-traumatic stress disorder. One-third of the admissions came from service members with 4 to 8 years' time in service and slightly more than one-third were employed in direct combat roles or medical support. In terms of gender, females accounted for one-quarter of the admissions.