Climate warming causes photobiont degradation and carbon starvation in a boreal climate sentinel lichen.

PREMISE: The long-term potential for acclimation by lichens to changing climates is poorly known, despite their prominent roles in forested ecosystems. Although often considered "extremophiles," lichens may not readily acclimate to novel climates well beyond historical norms. In a previous study (Smith et al., 2018), Evernia mesomorpha transplants in a whole-ecosystem climate change experiment showed drastic mass loss after 1 yr of warming and drying; however, the causes of this mass loss were not addressed. METHODS: We examined the causes of this warming-induced mass loss by measuring physiological, functional, and reproductive attributes of lichen transplants. RESULTS: Severe loss of mass and physiological function occurred above +2°C of experimental warming. Loss of algal symbionts ("bleaching") and turnover in algal community compositions increased with temperature and were the clearest impacts of experimental warming. Enhanced CO2 had no significant physiological or symbiont composition effects. The functional loss of algal photobionts led to significant loss of mass and specific thallus mass (STM), which in turn reduced water-holding capacity (WHC). Although algal genotypes remained detectable in thalli exposed to higher stress, within-thallus photobiont communities shifted in composition toward greater diversity. CONCLUSIONS: The strong negative impacts of warming and/or lower humidity on Evernia mesomorpha were driven by a loss of photobiont activity. Analogous to the effects of climate change on corals, the balance of symbiont carbon metabolism in lichens is central to their resilience to changing conditions.

Awareness and Counseling Among Dermatologists of the Association Between Hydrochlorothiazide and Nonmelanoma Skin Cancer: Barriers and Opportunities.

BACKGROUND: Cumulative hydrochlorothiazide (HCTZ) use is linked to the development of nonmelanoma skin cancers. In August 2020, the U.S. FDA approved changes to the HCTZ drug label to indicate this. OBJECTIVE: To uncover what proportion of dermatologists are aware of this association and how often screening and counseling are performed. MATERIALS AND METHODS: An observational, cross-sectional survey assessing risk awareness and counseling frequency and barriers was distributed among academic dermatologists. Chi-square tests compared resident and attending respondent data. RESULTS: A total of 83 respondents completed the questionnaire; most endorsed awareness of the association between HCTZ use and nonmelanoma skin cancer development before the survey, yet only 28.9% of respondents were aware of changes to the HCTZ drug label. A greater proportion of attendings than residents were aware of the association and drug label changes. The most reported barrier to counseling was the lack of specific screening guidelines for patients taking HCTZ. CONCLUSION: Concerted efforts should be made in residency training and continuing medical education to ensure dermatologists are aware of this well-established link. Specialty-specific efforts should be made to implement clear guidelines on best screening practices and optimized counseling strategies for patients taking HCTZ.

Effects of dipeptidyl peptidase-4 inhibitors and sulphonylureas on cognitive and physical function in nursing home residents.

AIMS: Dipeptidyl peptidase-4 inhibitors (DPP4Is) may mitigate hypoglycaemia-mediated declines in cognitive and physical functioning compared with sulphonylureas (SUs), yet comparative studies are unavailable among older adults, particularly nursing home (NH) residents. We evaluated the effects of DPP4Is versus SUs on cognitive and physical functioning among NH residents. MATERIALS AND METHODS: This new-user cohort study included long-stay NH residents aged ≥65 years from the 2007-2010 national US Minimum Data Set (MDS) clinical assessments and linked Medicare claims. We measured cognitive decline from the validated 6-point MDS Cognitive Performance Scale, functional decline from the validated 28-point MDS Activities of Daily Living scale, and hospitalizations or emergency department visits for altered mental status from Medicare claims. We compared 180-day outcomes in residents who initiated a DPP4I versus SU after 1:1 propensity score matching using Cox regression models. RESULTS: The matched cohort (N = 1784) had a mean ± SD age of 80 ± 8 years and 73% were women. Approximately 46% had no or mild cognitive impairment and 35% had no or mild functional impairment before treatment initiation. Compared with SU users, DPP4I users had lower 180-day rates of cognitive decline [hazard ratio (HR) = 0.61, 95% confidence interval (CI) 0.31-1.19], altered mental status events (HR = 0.71, 95% CI 0.39-1.27), and functional decline (HR = 0.89, 95% CI 0.51-1.56), but estimates were imprecise. CONCLUSIONS: Rates of cognitive and functional decline may be reduced among older NH residents using DPP4Is compared with SUs, but larger studies with greater statistical power should resolve the remaining uncertainty by providing more precise effect estimates.

Reconciling multiple counterfactuals when evaluating biodiversity conservation impact in social-ecological systems.

When evaluating the impact of a biodiversity conservation intervention, a counterfactual is typically needed. Counterfactuals are possible alternative system trajectories in the absence of an intervention. Comparing observed outcomes against the chosen counterfactual allows the impact (change attributable to the intervention) to be determined. Because counterfactuals by definition never occur, they must be estimated. Sometimes, there may be many plausible counterfactuals, including various drivers of biodiversity change and defined on a range of spatial or temporal scales. Here, we posit that, by definition, conservation interventions always take place in social-ecological systems (SES) (i.e., ecological systems integrated with human actors). Evaluating the impact of an intervention in an SES, therefore, means taking into account the counterfactuals assumed by different human actors. Use of different counterfactuals by different actors will give rise to perceived differences in the impacts of interventions, which may lead to disagreement about its success or the effectiveness of the underlying approach. Despite that there are biophysical biodiversity trends, it is often true that no single counterfactual is definitively the right one for conservation assessment, so multiple evaluations of intervention efficacy could be considered justifiable. Therefore, we propose calculating the sum of perceived differences, which captures the range of impact estimates associated with different actors in a given SES. The sum of perceived differences gives some indication of how closely actors in an SES agree on the impacts of an intervention. We applied the concept of perceived differences to a set of global, national, and regional case studies (e.g., global realization of Aichi Target 11 for marine protected areas, effect of biodiversity offsetting on vegetation condition in Australia, and influence of conservation measures on an endangered ungulate in Central Asia). We explored approaches for minimizing the sum, including a combination of negotiation and structured decision making, careful alignment of expectations on scope and measurement, and explicit recognition of any intractable differences between stakeholders.

Reconciliación de Múltiples Hipótesis de Contraste al Evaluar el Impacto de la Conservación de la Biodiversidad en los Sistemas Socio-Ecológicos Resumen Cuando se evalúa el impacto de una intervención de conservación de la biodiversidad, generalmente se requiere una hipótesis de contraste. Las hipótesis de contraste son las posibles trayectorias alternativas del sistema en ausencia de una intervención. La comparación de los resultados observados con la hipótesis de contraste elegida permite que se determine el impacto (cambio atribuible a la intervención). Ya que las hipótesis de contraste por definición nunca ocurren, éstas deben ser estimadas. En algunos casos es posible que existan muchas hipótesis de contraste, incluyendo a muchos conductores del cambio en la biodiversidad, y que estén definidas bajo una gama de escalas espaciales o temporales. En este artículo planteamos que, por definición, las intervenciones de conservación siempre ocurren en sistemas socioecológicos (SES) (es decir, sistemas ecológicos integrados con actores humanos). Por lo tanto, la evaluación del impacto de una intervención en un SES implica la consideración de las hipótesis de contraste asumidas por los diferentes actores humanos. El uso de diferentes hipótesis de contraste por los diferentes actores hará que surjan diferencias percibidas en los impactos de las intervenciones, lo que puede llegar a discrepancias sobre su éxito o sobre la efectividad de la estrategia subyacente. A pesar de que existen tendencias biofísicas de la biodiversidad, con frecuencia es cierto que no hay una sola hipótesis de contraste que sea correcta de manera definitiva para la evaluación de la conservación, por lo que múltiples evaluaciones de la eficiencia de la intervención podrían considerarse como justificables. Así, proponemos que se calcule la suma de las diferencias percibidas, la cual captura la gama de las estimaciones de impacto asociadas con diferentes actores en un SES dado. La suma de las diferencias percibidas nos da algún tipo de indicación sobre cuán de acuerdo están los actores de un SES sobre los impactos de una intervención. Aplicamos el concepto de diferencias percibidas a un conjunto de estudios de caso mundiales, nacionales y regionales (p. ej.: la realización mundial del Objetivo Aichi 11 para las áreas marinas protegidas, el efecto de la compensación de la biodiversidad sobre las condiciones botánicas en Australia y la influencia de las medidas de conservación sobre un ungulado en peligro en Asia central). Exploramos las estrategias para minimizar la suma, incluyendo una combinación de negociación y toma estructurada de decisiones, la alineación cuidadosa de las expectativas sobre el enfoque y la medida y el reconocimiento explícito de cualquier diferencia intratable entre los actores sociales.

Motivations for the use and consumption of wildlife products.

The dominant approach to combating the illegal wildlife trade has traditionally been to restrict the supply of wildlife products. Yet conservationists increasingly recognize the importance of implementing demand-side interventions that target the end consumers in the trade chain. Their aim is to curb the consumption of wildlife or shift consumption to more sustainable alternatives. However, there are still considerable knowledge gaps in understanding of the diversity of consumer motivations in the context of illegal wildlife trade, which includes hundreds of thousands of species, different uses, and diverse contexts. Based on consultation with multiple experts from a diversity of backgrounds, nationalities, and focal taxa, we developed a typology of common motivations held by wildlife consumers that can be used to inform conservation interventions. We identified 5 main motivational categories for wildlife use: experiential, social, functional, financial, and spiritual, each containing subcategories. This framework is intended to facilitate the segmentation of consumers based on psychographics and allow the tailoring of interventions-whether behavior change campaigns, enforcement efforts, or incentive programs-to the specific context in which they will be used. Underlining the importance of consumer research and collaborating with local actors is an important step toward promoting a more systematic approach to the design of demand reduction interventions.

Motivaciones para el Uso y Consumo de Productos de Fauna Resumen Tradicionalmente, la estrategia dominante para combatir el mercado ilegal de fauna ha sido restringir la oferta de productos de fauna. Aun así, los conservacionistas cada vez reconocen más la importancia de implementar intervenciones por el lado de la demanda que se enfoquen en los consumidores finales en la cadena de mercado. Su objetivo es reducir el consumo de fauna o redirigir ese consumo hacia alternativas más sustentables. Sin embargo, todavía existen vacíos de conocimiento en el entendimiento de la diversidad de motivos para los consumidores dentro del contexto del mercado ilegal de fauna, el cual incluye cientos de miles de especies, diferentes usos y contextos diversos. Con base en consultas a varios expertos con una diversidad de antecedentes, nacionalidades y taxones de enfoque desarrollamos una tipología de motivos comunes que tienen los consumidores de fauna que pueden usarse para orientar las intervenciones de conservación. Identificamos cinco categorías principales de motivos para el uso de fauna: vivencial, social, funcional, financiero y espiritual, cada uno con subcategorías. Este marco de trabajo tiene la intención de facilitar la segmentación de consumidores con base en psicográficos y permitir la personalización de las intervenciones - sean campañas de cambios en el comportamiento, esfuerzos por hacer cumplir las reglas o programas de incentivos - al contexto específico en el que serán utilizadas. Resaltar la importancia de los estudios de mercado y la colaboración con los actores locales es un paso importante hacia la promoción de una estrategia más sistemática para el diseño de intervenciones para reducir la demanda.

Dermatologic support for oncology: Quantifying the consultative services received by hospitalized oncology patients.

Hospitalized oncology patients often require multidisciplinary care. Inpatient consultative dermatologists can provide expertise in the management of cutaneous complications that patients with cancer may experience. The goal of this study was to quantify the types of consults received by hospitalized oncology patients to better understand the utilization of dermatology consults in this population. Hospital billing codes were used to identify inpatient oncology patients and the types of consults they received at a single quaternary care hospital center. Between July 1, 2015, and January 31, 2020, 14,175 patients were admitted to an oncology service for more than 24 hours, and 5,243 (37%) of these patients received at least 1 consultation during their hospital admission. These patients received a total of 10,492 consults from 101 different services. Dermatology had the fifth-highest number of consults (n = 623; 5.9%). Among patients receiving consults, 608 (11.6%) received inpatient dermatology consults. Infectious disease was the service with the most consults (n = 1,485; 14.2%) and was also the service most commonly co-consulted with dermatology (n = 262; 42.1%). The inpatient consultative dermatology service is highly utilized among hospitalized oncology patients, suggesting that expertise in dermatologic care is valued by oncology teams.

Facebook language predicts depression in medical records.

Depression, the most prevalent mental illness, is underdiagnosed and undertreated, highlighting the need to extend the scope of current screening methods. Here, we use language from Facebook posts of consenting individuals to predict depression recorded in electronic medical records. We accessed the history of Facebook statuses posted by 683 patients visiting a large urban academic emergency department, 114 of whom had a diagnosis of depression in their medical records. Using only the language preceding their first documentation of a diagnosis of depression, we could identify depressed patients with fair accuracy [area under the curve (AUC) = 0.69], approximately matching the accuracy of screening surveys benchmarked against medical records. Restricting Facebook data to only the 6 months immediately preceding the first documented diagnosis of depression yielded a higher prediction accuracy (AUC = 0.72) for those users who had sufficient Facebook data. Significant prediction of future depression status was possible as far as 3 months before its first documentation. We found that language predictors of depression include emotional (sadness), interpersonal (loneliness, hostility), and cognitive (preoccupation with the self, rumination) processes. Unobtrusive depression assessment through social media of consenting individuals may become feasible as a scalable complement to existing screening and monitoring procedures.

Painful scrotal dermatitis secondary to topical 5-fluorouracil.

5-Fluorouracil (5-FU) is an antineoplastic agent that is used topically to treat actinic keratoses. Although topical 5-FU frequently causes irritant contact dermatitis at the site of application, distant skin reactions are rare and could relate to accidental transfer or systemic absorption of the drug. We present a patient who developed a painful scrotal dermatitis after applying the topical cream to actinic keratoses on his chest. Upon discontinuation of topical 5-FU, the reaction resolved over a four-week period with oral prednisone and topical betamethasone ointment. The patient was re-challenged with topical 5-FU one year later and again developed scrotal pain and erythema similar to the initial reaction. Scrotal dermatitis is a rare adverse effect of topical 5-FU therapy that can be associated with significant distress and disruption of daily activities.

Pediatric nail disorders: a review.

PURPOSE OF REVIEW: Nail disorders represent an uncommon subset of complaints seen in pediatric dermatology. There is a wide array of disorders that can affect the nail unit in children, including infectious, inflammatory, neoplastic, congenital, and traumatic processes. In order to enhance familiarity with pediatric nail conditions, we review the background and treatment of the more common entities seen in pediatric onychology, including onychomycosis, onychomadesis, nail psoriasis, trachyonychia, longitudinal melanonychia, onychophagia, and onychocryptosis. RECENT FINDINGS: Nail involvement in pediatric patients with psoriasis may indicate increased risk for both overall disease severity and the development psoriatic arthritis. In the evaluation of longitudinal melanonychia, the clinical findings that raise concern for subungual melanoma in adults are often found in benign nail unit nevi in children. In the systemic treatment of pediatric onychomycosis, new data raises the possibility that laboratory monitoring may be approached differently. In the approach to onychophagia, emerging pharmacotherapies include N-acetylcysteine. SUMMARY: Most nail disorders in pediatric patients have an overall favorable prognosis. However, nail abnormalities can lead to patient and parental anxiety, decreased quality of life, pain, and functional impairment. Clinicians should be aware of these more common diverse entities in order to identify them and apply state of the art management for these issues. Additionally, the reader will learn factors related to these nail disorders, which may require systemic work-up and/or specialist referral.

Segmental congenital hemangiomas: Three cases of a rare entity.

Congenital hemangiomas (CHs) are unusual and diverse tumors distinguished from infantile hemangiomas by being largely developed at birth and glucose transporter (GLUT1)-negative. We describe three infants who presented in utero or at birth with segmentally distributed vascular tumors that were GLUT1-negative, had histology compatible with congenital hemangioma, and exhibited spontaneous clinical involution. One of the three patients had high-output cardiac failure and was found to have a mutation in GNAQ (c.626A>c, p.Gln209Pro); another had high-output cardiac failure, heterotaxy, and transient hematologic abnormalities and was found to have a mutation in GNA11 (c.626_627delinsCC, p.Gln209Pro). In addition to describing a novel segmental pattern of congenital hemangioma variant with genetic correlations, these cases illustrate the utility of targeted genetic testing to elucidate the exact mutation and thus classification of vascular tumors.

Arrival timing and the influence of weather experienced during the nonbreeding and breeding periods on correlates of reproductive success in female field sparrows (Spizella pusilla) breeding in northeastern Pennsylvania, USA.

Increasing evidence suggests that the environment encountered by migrating landbirds during the nonbreeding season, including temperature and precipitation, may influence individuals and population processes in subsequent seasons. However, to date, most studies have focused on linkages between factors encountered during the wintering and breeding periods in long-distance, primarily insectivorous landbirds. Here, we take advantage of a long-term (23 breeding seasons) data set on the arrival and breeding ecology of female field sparrows (Spizella pusilla), a granivorous, short-distance species that winters in the southeastern USA, to look for time periods (windows) over the preceding winter and spring migratory periods when average daily precipitation or temperature may have influenced when a female arrived at breeding grounds in northeastern Pennsylvania and correlates of seasonal reproductive performance. We employed a sliding window analysis approach using weather data obtained from the south of our site (to evaluate effects of weather experienced during the nonbreeding period) and, separately, near our site (to evaluate effects of weather experienced during the breeding period), finding windows in which temperature and precipitation during the nonbreeding period were associated with arrival timing and clutch initiation day and a window in which temperature experienced during the breeding period was associated with clutch initiation day. We did not, however, find evidence that temperature or precipitation, either during the nonbreeding period or breeding period, was associated with clutch size nor total egg volume. Finally, early arriving females initiated clutches early, produced larger clutches, more nests, and more total eggs than later arriving females. Our findings contribute to the growing body of evidence that events experienced prior to the breeding season may influence individuals and population processes in subsequent seasons.

Novel climates reverse carbon uptake of atmospherically dependent epiphytes: Climatic constraints on the iconic boreal forest lichen Evernia mesomorpha.

PREMISE OF THE STUDY: Changing climates are expected to affect the abundance and distribution of global vegetation, especially plants and lichens with an epiphytic lifestyle and direct exposure to atmospheric variation. The study of epiphytes could improve understanding of biological responses to climatic changes, but only if the conditions that elicit physiological performance changes are clearly defined. METHODS: We evaluated individual growth performance of the epiphytic lichen Evernia mesomorpha, an iconic boreal forest indicator species, in the first year of a decade-long experiment featuring whole-ecosystem warming and drying. Field experimental enclosures were located near the southern edge of the species' range. KEY RESULTS: Mean annual biomass growth of Evernia significantly declined 6 percentage points for every +1°C of experimental warming after accounting for interactions with atmospheric drying. Mean annual biomass growth was 14% in ambient treatments, 2% in unheated control treatments, and -9% to -19% (decreases) in energy-added treatments ranging from +2.25 to +9.00°C above ambient temperatures. Warming-induced biomass losses among persistent individuals were suggestive evidence of an extinction debt that could precede further local mortality events. CONCLUSIONS: Changing patterns of warming and drying would decrease or reverse Evernia growth at its southern range margins, with potential consequences for the maintenance of local and regional populations. Negative carbon balances among persisting individuals could physiologically commit these epiphytes to local extinction. Our findings illuminate the processes underlying local extinctions of epiphytes and suggest broader consequences for range shrinkage if dispersal and recruitment rates cannot keep pace.

Trachelas tranquillus envenomation with presumed bacterial superinfection in a child.

A 27-month-old girl with a history of congenital myopathy presented with two indurated, pink plaques involving the right arm and left thigh. Closer examination identified central puncta within these plaques, which reportedly occurred at sites of witnessed arachnid bites. After confirmation of the spider species as Trachelas tranquillus, she was treated to address cutaneous inflammation and suspected superinfection using oral and topical antibiotics as well as topical corticosteroid resulting in prompt resolution of her lesions. Trachelas tranquillus should be considered as a possible source of inflammatory spider bites that can become superinfected.

Retrospective review of immunocompromised children undergoing skin biopsy for suspected invasive infection: Analysis of factors predictive of invasive mold.

OBJECTIVES: Cutaneous lesions are often the first marker of invasive mold infection, which can cause substantial morbidity in immunocompromised children. The purpose of this study was to describe the evaluation and outcomes of immunocompromised children who presented with findings requiring skin biopsy because of concern about invasive infection. In children who were biopsied, we sought to determine the factors predictive of invasive mold infection. METHODS: A retrospective review was conducted at the Children's Hospital of Philadelphia. Patients included in the study were immunocompromised individuals younger than 26 years old who underwent skin biopsy by the inpatient dermatology consultation team between January 1, 2003, and March 15, 2015, because of development of new cutaneous lesions that were suspected of being invasive infection. RESULTS: One hundred five encounters met the inclusion criteria. Fifty (47.6%) biopsied individuals had an infectious pathogen identified on histopathology or culture. Mold was the most common (36%) pathogen, followed by bacteria (32%) and yeast (26%). The presence of a single lesion (P = .001) and prior occlusion at the site of the lesion (P < .001) were associated with mold on biopsy. The combination of a single lesion, history of occlusion, and tissue necrosis on examination was highly predictive for invasive mold infection (86.3% [95% confidence interval 55.1-97.0%]). Of the 18 individuals with confirmed invasive mold infection, 13 (72%) underwent surgical resection, of whom 12 (92%) survived the 30-day follow-up period. CONCLUSION: Skin biopsy enabled the detection of a pathogen that informed directed therapeutic interventions in nearly half of participants. Institutions caring for immunocompromised children should ensure adequate staffing of clinical personnel approved to perform skin biopsies.

Targeting global protected area expansion for imperiled biodiversity.

Governments have agreed to expand the global protected area network from 13% to 17% of the world's land surface by 2020 (Aichi target 11) and to prevent the further loss of known threatened species (Aichi target 12). These targets are interdependent, as protected areas can stem biodiversity loss when strategically located and effectively managed. However, the global protected area estate is currently biased toward locations that are cheap to protect and away from important areas for biodiversity. Here we use data on the distribution of protected areas and threatened terrestrial birds, mammals, and amphibians to assess current and possible future coverage of these species under the convention. We discover that 17% of the 4,118 threatened vertebrates are not found in a single protected area and that fully 85% are not adequately covered (i.e., to a level consistent with their likely persistence). Using systematic conservation planning, we show that expanding protected areas to reach 17% coverage by protecting the cheapest land, even if ecoregionally representative, would increase the number of threatened vertebrates covered by only 6%. However, the nonlinear relationship between the cost of acquiring land and species coverage means that fivefold more threatened vertebrates could be adequately covered for only 1.5 times the cost of the cheapest solution, if cost efficiency and threatened vertebrates are both incorporated into protected area decision making. These results are robust to known errors in the vertebrate range maps. The Convention on Biological Diversity targets may stimulate major expansion of the global protected area estate. If this expansion is to secure a future for imperiled species, new protected areas must be sited more strategically than is presently the case.

Synthesis of Chromones from 1,1-Diacylcyclopropanes: Toward the Synthesis of Bromophycoic Acid E.

A tandem deprotection-cyclization reaction of 1,1-diacylcyclopropanes is described which allows rapid access to structurally diverse 2,3-disubstituted chromones in good yields, and with straightforward purification. The utility of this reaction is showcased by the construction of the potent antibacterial marine natural product bromophycoic acid E scaffold.

Variations in Facebook Posting Patterns Across Validated Patient Health Conditions: A Prospective Cohort Study.

BACKGROUND: Social media is emerging as an insightful platform for studying health. To develop targeted health interventions involving social media, we sought to identify the patient demographic and disease predictors of frequency of posting on Facebook. OBJECTIVE: The aims were to explore the language topics correlated with frequency of social media use across a cohort of social media users within a health care setting, evaluate the differences in the quantity of social media postings across individuals with different disease diagnoses, and determine if patients could accurately predict their own levels of social media engagement. METHODS: Patients seeking care at a single, academic, urban, tertiary care emergency department from March to October 2014 were queried on their willingness to share data from their Facebook accounts and electronic medical records (EMRs). For each participant, the total content of Facebook posts was extracted. Using the latent Dirichlet allocation natural language processing technique, Facebook language topics were correlated with frequency of Facebook use. The mean number of Facebook posts over 6 months prior to enrollment was then compared across validated health outcomes in the sample. RESULTS: A total of 695 patients consented to provide access to their EMR and social media data. Significantly correlated language topics among participants with the highest quartile of posts contained health terms, such as "cough," "headaches," and "insomnia." When adjusted for demographics, individuals with a history of depression had significantly higher posts (mean 38, 95% CI 28-50) than individuals without a history of depression (mean 22, 95% CI 19-26, P=.001). Except for depression, across prevalent health outcomes in the sample (hypertension, diabetes, asthma), there were no significant posting differences between individuals with or without each condition. CONCLUSIONS: High-frequency posters in our sample were more likely to post about health and to have a diagnosis of depression. The direction of causality between depression and social media use requires further evaluation. Our findings suggest that patients with depression may be appropriate targets for health-related interventions on social media.

The impact of human and vector distributions on the spatial prevalence of malaria in sub-Saharan Africa.

Eradication of malaria from the world in the latter part of the twentieth century proved an elusive, albeit desirable, objective. Unfortunately, resurgence of malarial incidence is currently underway. Key to understanding effective control schemes such as indoor residual spraying (spraying insecticide inside houses to kill the malarial vector mosquitoes) is the impact of spatial distributions for communities exposed to the malarial vector mosquito populations. Densities of human dwellings in small communities vary considerably in regions exposed to larval breeding sites. We extend prior modelling work to explore the spatial impact and diffusive transport of mosquito population densities on various distributions of human populations on relatively small landscape representations. Bistable dynamics of our reaction-diffusion model, which excludes advective transport, suggest two temporal phases for infection. An initial rapid phase occurs during transitions from initial homogeneous or spatially confined infections to peak levels over the course of days, and a relaxation phase develops to a steady state over weeks or months, suggesting successful intervention methods likely require recognising the phase of infection. We further observe a strong dependence of human infection and recovery on distributions of susceptible human populations with some degree of independence from mosquito distributions given an adequate supply of mosquito vectors to sustain infections. A subtle and complex interplay between human dwelling densities, mosquito diffusion and infection rates also emerges. With a sufficiently fast diffusive transport of mosquitoes, our model indicates that relative timescales for infection rates are slower, leading to lower rates of infection. This suggests that, although we here only include diffusive transport, if mosquitoes are subject to rapid enough movement (e.g., wind), communities situated in windy areas are exposed to less infectious risk than those in non-windy areas. This should help to guide intervention strategies with geographical considerations in mind. Our implementation of a reaction-diffusion model here further reveals some issues regarding continuum methods for population and infectious disease models that suggest consideration of discrete spatial methods (e.g., agent-based) for future work.