A dynamical trichotomy for structured populations experiencing positive density-dependence in stochastic environments

Positive density-dependence occurs when individuals experience increased survivorship, growth, or reproduction with increased population densities. Mechanisms leading to these positive relationships include mate limitation, saturating predation risk, and cooperative breeding and foraging. Individuals within these populations may differ in age, size, or geographic location and thereby structure these populations. Here, I study structured population models accounting for positive density-dependence and environmental stochasticity i.e. random fluctuations in the demographic rates of the population. Under an accessibility assumption (roughly, stochastic fluctuations can lead to populations getting small and large), these models are shown to exhibit a dynamical trichotomy: (i) for all initial conditions, the population goes asymptotically extinct with probability one, (ii) for all positive initial conditions, the population persists and asymptotically exhibits unbounded growth, and (iii) for all positive initial conditions, there is a positive probability of asymptotic extinction and a complementary positive probability of unbounded growth. The main results are illustrated with applications to spatially structured populations with an Allee effect and age-structured populations experiencing mate limitation

Premenarchal Girls' Genital Examination Experiences

Purpose To explore girls' experiences having an external genital examination during early adolescence. Methods Ten premenarchal girls were interviewed about their experiences receiving an external genital examination as part of a larger longitudinal study. Qualitative methods were used for analysis, looking for concepts based on themes and shared beliefs among the girls to create a model of the genital examination experience. Results Most participants could not remember ever having a genital examination before enrollment in the larger study. The examination was best characterized as “weird,” and many aspects of the examination were novel. Overall, genital examinations were not experienced negatively because of moderating factors like having support from mothers during the examination and having examiner preferences toward gender and personal characteristics. With repeated study examinations in the larger study and for those participants who reported their provider performed genital examinations, the examination was viewed as a skill for growing up or routine. Conclusions External genital examinations, although a new experience for many girls, can be experienced positively. Providers should address concerns about this important recommended examination and acknowledge that examiner attributes, mothers, and experience of having examinations all influence how genital examinations are experienced

Redefining the Social Geography of Community STI Risk: An Ecological Study of the Association, Mediators, and Moderators of Area-Level Prostitution Arrests

Background: Core groups such as sex workers have been implicated in contributing to higher area STI risk but no studies have analyzed mediators and moderators of this relationship using population data. Objectives: Assess the overall association of area-level prostitution and STI risk, and mediators and moderators of the relationship. Methods: Point-level prostitution and drug arrests were geocoded and aggregated by Census blockgroup. Chlamydia (CT), gonorrhea (GC), syphilis and incident HIV positive test results were aggregated by blockgroup after eliminating same-organism positive tests within 14 days of an initial positive test. Census data also defined moderators: blockgroups with >75% black and >20% Latino (top decile) and >60% below 200% of the federal poverty line (top quartile). Negative binomial and zero-inflated negative binomial regressions were used to estimate incident rate ratios (IRR) of each STI. Results: There was a dose-response relationship between prostitution arrest blockgroup quintiles and IRR of each STI. In models including drug arrest data, this association was completely eliminated. Though % black blockgroup composition had significant interaction with prostitution arrest rates and with respect to its relationship with STI IRR, % Latino did not consistently have this association. Blockgroups with proportions of low minority and low poverty had highest drug arrest IRR for each STI. In these areas, prostitution arrest IRR were only significant for CT and GC and were consistently lower than drug arrest IRRs. Conclusions: Though prostitution arrests are associated with STI risk, this relationship is mediated by drug arrests. Associations of both arrest rates are strongest in low minority, low poverty communities, indicating that high baseline STI prevalence is not moderated by levels of drug and prostitution arrests. Implications for Programs, Policy, and Research: These data suggest that important relationships exist for prostitution and, to a greater degree, drug arrests within communities traditionally defined as ‘low-risk’

Geographical gradients in diet affect population dynamics of Canada lynx

Geographical gradients in the stability of cyclic populations of herbivores and their predators may relate to the degree of specialization of predators. However, such changes are usually associated with transition from specialist to generalist predator species, rather than from geographical variation in dietary breadth of specialist predators. Canada lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) populations undergo cyclic. fluctuations in northern parts of their range, but cycles are either greatly attenuated or lost altogether in the southern boreal forest where prey diversity is higher. We tested the influence of prey specialization on population cycles by measuring the stable carbon and nitrogen isotope ratios in lynx and their prey, estimating the contribution of hares to lynx diet across their range, and correlating this degree of specialization to the strength of their population cycles. Hares dominated the lynx diet across their range, but specialization on hares decreased in southern and western populations. The degree of specialization correlated with cyclic signal strength indicated by spectral analysis of lynx harvest data, but overall variability of lynx harvest (the standard deviation of natural-log-transformed harvest numbers) did not change significantly with dietary specialization. Thus, as alternative prey became more important in the lynx diet, the fluctuations became decoupled from a regular cycle but did not become less variable. Our results support the hypothesis that alternative prey decrease population cycle regularity but emphasize that such changes may be driven by dietary shifts among dominant specialist predators rather than exclusively through changes in the predator community

Use of Cell Phone Diaries to Understand Risk Contexts of Sexual Events Among Female Sex Workers

Background Data collection using mobile technologies, such as cell phones, allows more frequent and real-time data collection and is less prone to recall bias. We describe the feasibility of using twice daily cell phone diaries to capture contextual features of STI/HIV-risk that could impact disease acquisition among female sex workers (FSW). Methods Women engaging in transactional sex in the prior 90 days were recruited utilising incentivized snowball sampling. Participants completed STI testing and baseline/exit surveys. Over 4-weeks, they completed twice-daily electronic diaries assessing event-level sexual behaviour, condom use, and drug use. Weekly in-person interviews used open-ended questions to explore geographical characteristics of sexual encounter locations as well as acceptability of event-level monitoring. Results 25/26 participants (median age 43.5 years) completed the 4-week study. At baseline, 27% tested positive for a STI. Participants completed 84.5% of 1,518 expected surveys and 95% of 106 expected interviews. Patterns of diary compliance were stable over time. Partnered sexual activity was captured in 21.4% of diaries. At the participant-level, most reported giving oral sex (84.7%) or vaginal sex (96.1%); fewer (19.2%) reported engaging in anal sex. Among women reporting partnered sexual behaviour with any partner type (i.e., new/regular customers, romantic partners), using condoms was reported 39.2%, 45.5% and 83.3% of the time for giving oral sex, vaginal sex, and anal sex respectively. At the event-level, the frequency of giving oral sex, vaginal sex or anal sex did not significantly change over time. Conclusions It is feasible to engage and retain FSW in a technologically-advanced study to characterise risk contexts of sexual events. Adherence to study protocol was high indicating event-level monitoring using cell phone based diaries is acceptable. These data can be utilised to improve our understanding of the individual, relational and environmental factors that influence STI/HIV acquisition among FSW

Antibiotic therapeutic drug monitoring in intensive care patients treated with different modalities of extracorporeal membrane oxygenation (ECMO) and renal replacement therapy: a prospective, observational single-center study

Background: Efective antimicrobial treatment is key to reduce mortality associated with bacterial sepsis in patients on intensive care units (ICUs). Dose adjustments are often necessary to account for pathophysiological changes or renal replacement therapy. Extracorporeal membrane oxygenation (ECMO) is increasingly being used for the treatment of respiratory and/or cardiac failure. However, it remains unclear whether dose adjustments are necessary to avoid subtherapeutic drug levels in septic patients on ECMO support. Here, we aimed to evaluate and comparatively assess serum concentrations of continuously applied antibiotics in intensive care patients being treated with and without ECMO. Methods: Between October 2018 and December 2019, we prospectively enrolled patients on a pneumological ICU in southwest Germany who received antibiotic treatment with piperacillin/tazobactam, ceftazidime, meropenem, or linezolid. All antibiotics were applied using continuous infusion, and therapeutic drug monitoring of serum concentrations (expressed as mg/L) was carried out using high-performance liquid chromatography. Target concentrations were defned as fourfold above the minimal inhibitory concentration (MIC) of susceptible bacterial isolates, according to EUCAST breakpoints

Prospectus, October 17, 1984

SPORTS FEATURE LADY COBRAS TAKE IV INVITATIONAL; Assistance available; many services offered; Speech team takes honors; Goal is to overthrow the \u27masculine mind\u27; PC Happenings; Parkland hosts Foley exhibit; TV for Parents and Kids debuts; Workshop focuses on sexual abuse of young children; Career restructuring focus of workshop; Hearing topic for retirees; International students enrich us all; Did You Know...; Creative Corner...Especially for you!!; Paper Dolls Souls; History; Depression; Alone; Being & Becoming; So Much; Breakable Item; Thumbism; Diary; \u27Doom Story\u27-the terror escalates; Excerpts from Some Late Evening Thoughts While Anticipating That First Great Thunderstorm of a Dry Month; Midnight; Strength or weakness; The Ultimate Weapon; Photographer captures essence of traditional, contemporary Latin America; Celebrate the Arts Week; WPCD DJ likes job, Parkland; TV programs for parents scheduled; Classifieds; Peter Pan syndrome causes relationship problems; Experience Blues Explosion; Two comedians better than one; 1978 was cruel summer for Sullivan; 1984 is proving to be a sweet fall; Drive on to educate-issues important; Powell wins invitational; Stewart places 4th; Peterson prefers to use an eight-ironhttps://spark.parkland.edu/prospectus_1984/1008/thumbnail.jp

In vivo safety profile and biodistribution of GMP-manufactured human skin-derived ABCB5-positive mesenchymal stromal cells for use in clinical trials

Background aims Human dermal ABCB5-expressing mesenchymal stromal cells (ABCB5+ MSCs) represent a promising candidate for stem cell–based therapy of various currently uncurable diseases in several fields of regenerative medicine. We have developed and validated a method to isolate, from human skin samples, and expand ABCB5+ MSCs that meet the guideline criteria of the International Society for Cellular Therapy. We are able to process these cells into a Good Manufacturing Practice–conforming, MSC-based advanced-therapy medicinal product. Methods To support the development of ABCB5+ MSCs for potential therapeutic topical, intramuscular and intravenous administration, we have tested our product in a series of Good Laboratory Practice–compliant nonclinical in-vivo studies addressing all relevant aspects of biosafety, including potential long-term persistence and proliferation, distribution to nontarget tissues, differentiation into undesired cell types, ectopic tissue formation, tumor formation and local tissue reaction. Results (i) Subcutaneous application of 1 × 107 ABCB5+ MSCs/animal and intravenous application of 2 × 106 ABCB5+ MSCs/animal, respectively, to immunocompromised mice did not result in safety-relevant biodistribution, persistence or proliferation of the cells; (ii) three monthly subcutaneous injections of ABCB5+ MSCs at doses ranging from 1 × 105 to 1 × 107 cells/animal and three biweekly intravenous injections of 2 × 106 ABCB5+ MSCs/animal, respectively, to immunocompromised mice were nontoxic and revealed no tumorigenic potential; and (iii) intramuscular injection of 5 × 106 ABCB5+ MSCs/animal to immunocompromised mice was locally well tolerated. Discussion The present preclinical in vivo data demonstrate the local and systemic safety and tolerability of a novel advanced-therapy medicinal product based on human skin-derived ABCB5+ MSCs

A keratin scaffold regulates epidermal barrier formation, mitochondrial lipid composition, and activity.

Keratin intermediate filaments (KIFs) protect the epidermis against mechanical force, support strong adhesion, help barrier formation, and regulate growth. The mechanisms by which type I and II keratins contribute to these functions remain incompletely understood. Here, we report that mice lacking all type I or type II keratins display severe barrier defects and fragile skin, leading to perinatal mortality with full penetrance. Comparative proteomics of cornified envelopes (CEs) from prenatal KtyI(-/-) and KtyII(-/-)(K8) mice demonstrates that absence of KIF causes dysregulation of many CE constituents, including downregulation of desmoglein 1. Despite persistence of loricrin expression and upregulation of many Nrf2 targets, including CE components Sprr2d and Sprr2h, extensive barrier defects persist, identifying keratins as essential CE scaffolds. Furthermore, we show that KIFs control mitochondrial lipid composition and activity in a cell-intrinsic manner. Therefore, our study explains the complexity of keratinopathies accompanied by barrier disorders by linking keratin scaffolds to mitochondria, adhesion, and CE formation

Structural and mechanistic insights into a Bacteroides vulgatus retaining N-acetyl-β-galactosaminidase that uses neighbouring group participation

Bacteroides vulgatus is a member of the human microbiota whose abundance is increased in patients with Crohn's disease. We show that a B. vulgatus glycoside hydrolase from the carbohydrate active enzyme family GH123, BvGH123, is an N-acetyl-β-galactosaminidase that acts with retention of stereochemistry, and, through a 3-D structure in complex with Gal-thiazoline, provide evidence in support of a neighbouring group participation mechanism