Factors influencing population density of stream-living Redband Trout in southeast Oregon, USA

Fisheries managers often use models of population density to evaluate the status of stream-living fishes, but many of these models have low predictive performance for abundance and density. These models could incorporate several factors that can limit population density, particularly the effect of body size, envisioned by the theory of self-thinning. In addition, constraints imposed on density by physical and biological habitat conditions in streams are important to consider. In this study, we describe a two-phase approach to predict density of stream-living fish. We started by modeling maximum density in relation to body size (length and mass) using quantile regression. We extracted residuals from these models (deviations from maximum predicted density, termed “residual density”). In a second phase of analysis, we applied generalized linear models to predict residual density in relation to habitat factors known to limit abundance of stream-living salmonids (temperature, discharge, and non-native species). Models were based on data from Redband Trout (Oncorhynchus mykiss spp.) sampled over 1615 site visits in the Northern Great Basin Region of southeast Oregon, USA. Results in the first phase of the analysis indicated strong evidence for the influence of body size on maximum fish densities in sampled stream reaches. However, in the second phase of the analysis, we found poor predictive capability for models attempting to correlate limiting habitat factors to residual density. The importance of body size as a predictor of population density is qualitatively consistent with theoretical expectations based on body size and density dependence in stream-living fish, as well as a host empirical studies reporting inverse relationships between body size and population density. Our inability to predict residual density of Redband Trout in this study is also consistent with a long history of variably successful attempts to predict density based on local environmental variables. Although there are several possible reasons for why density of stream-living is so difficult to predict based on environmental variables, body size is a consistently important factor. Given this, additional work to understand environmental drivers of body size may be a more productive route to better understand factors that ultimately drive population density of stream-living fishes

Factors Affecting Frequency Discrimination of Vibrotactile Stimuli: Implications for Cortical Encoding

BACKGROUND: Measuring perceptual judgments about stimuli while manipulating their physical characteristics can uncover the neural algorithms underlying sensory processing. We carried out psychophysical experiments to examine how humans discriminate vibrotactile stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Subjects compared the frequencies of two sinusoidal vibrations applied sequentially to one fingertip. Performance was reduced when (1) the root mean square velocity (or energy) of the vibrations was equated by adjusting their amplitudes, and (2) the vibrations were noisy (their temporal structure was irregular). These effects were super-additive when subjects compared noisy vibrations that had equal velocity, indicating that frequency judgments became more dependent on the vibrations' temporal structure when differential information about velocity was eliminated. To investigate which areas of the somatosensory system use information about velocity and temporal structure, we required subjects to compare vibrations applied sequentially to opposite hands. This paradigm exploits the fact that tactile input to neurons at early levels (e.g., the primary somatosensory cortex, SI) is largely confined to the contralateral side of the body, so these neurons are less able to contribute to vibration comparisons between hands. The subjects' performance was still sensitive to differences in vibration velocity, but became less sensitive to noise. CONCLUSIONS/SIGNIFICANCE: We conclude that vibration frequency is represented in different ways by different mechanisms distributed across multiple cortical regions. Which mechanisms support the “readout” of frequency varies according to the information present in the vibration. Overall, the present findings are consistent with a model in which information about vibration velocity is coded in regions beyond SI. While adaptive processes within SI also contribute to the representation of frequency, this adaptation is influenced by the temporal regularity of the vibration

Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis.

INTRODUCTION Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies. METHODS We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale. RESULTS We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11 930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias. CONCLUSIONS This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol

Localization of kisspeptin, NKB, and NK3R in the hypothalamus of gilts treated with the progestin altrenogest

Mechanisms in the brain controlling secretion of gonadotropin hormones in pigs, particularly luteinizing hormone (LH), are poorly understood. Kisspeptin is a potent LH stimulant that is essential for fertility in many species, including pigs. Neurokinin B (NKB) acting through neurokinin 3 receptor (NK3R) is involved in kisspeptin-stimulated LH release, but organization of NKB and NK3R within the porcine hypothalamus is unknown. Hypothalamic tissue from ovariectomized (OVX) gilts was used to determine the distribution of immunoreactive kisspeptin, NKB, and NK3R cells in the arcuate nucleus (ARC). Almost all kisspeptin neurons coexpressed NKB in the porcine ARC. Immunostaining for NK3R was distributed throughout the preoptic area (POA) and in several hypothalamic areas including the periventricular and retrochiasmatic areas but was not detected within the ARC. There was no colocalization of NK3R with gonadotropin-releasing hormone (GnRH), but NK3R-positive fibers in the POA were in close apposition to GnRH neurons. Treating OVX gilts with the progestin altrenogest decreased LH pulse frequency and reduced mean circulating concentrations of LH compared with OVX control gilts (P \u3c 0.01), but the number of kisspeptin and NKB cells in the ARC did not differ between treatments. The neuroanatomical arrangement of kisspeptin, NKB, and NK3R within the porcine hypothalamus confirms they are positioned to stimulate GnRH and LH secretion in gilts, though differences with other species exist. Altrenogest suppression of LH secretion in the OVX gilt does not appear to involve decreased peptide expression of kisspeptin or NKB

Geodemographic analysis of pediatric firearm injuries in Miami, FL

Firearm injuries (GSW) are a growing public health concern and leading cause of morbidity and mortality among children, yet predictors of injury remain understudied. This study examines the correlates of pediatric GSW within our county. We retrospectively queried an urban Level 1 trauma center registry for pediatric (0–18 years) GSW from September 2013 to January 2019, examining demographic, clinical, and injury information. We used a geographic information system to map GSW rates and perform spatial and spatiotemporal cluster analysis to identify zip code “hot spots.” 393 cases were identified. The cohort was 877% male, 87% African American, 10% Hispanic, and 22% Caucasian/Other. Injuries were 92% violence-related and 4% accidental, with 63% occurring outside school hours. Mortality was 12%, with 53% of deaths occurring in the resuscitation unit. Zip-level GSW rates ranged from 0 to 9 (per 1000 < 18 years) by incident address and 0–6 by home address. Statistically significant hot spots were in predominantly underserved African American and Hispanic neighborhoods. Geodemographic analysis of pediatric GSW injuries can be utilized to identify at-risk neighborhoods. This methodology is applicable to other metropolitan areas where targeted interventions can reduce the burden of gun violence among children. Retrospective study. Level III

Analyzing pediatric bicycle injuries using geo-demographic data

Bicycle accidents are potentially preventable, and helmets can mitigate the severity of injuries. The purpose of the study it to investigate geo-demographic areas to establish prevention policies and targeted programs. From October 2013 to March 2020 all bicycle injuries at a Level 1 trauma center were collected for ages ≤18 years. Demographics, injuries, and outcomes were analyzed. Incidents were aggregated to zip codes and the Local Indicators of Spatial Association (LISA) statistic was used to test for spatial clustering of injury rates per 10,000 children. Over the 8-year time period, 77 cases were identified with an average age of 13±4 years, 83% male and 48% non-Hispanic white. The majority of patients (98%) were not wearing a helmet. Loss of consciousness was reported in 44% and 21% sustained a traumatic brain injury. Twenty-eight percent required ICU care and 36% required operative interventions. There was only 1 mortality in the cohort (<1%).Injuries were more common in lower household income zip codes (Figure 1). Six zip codes encompassing several interstate exits and the connected heavy-traffic roadways comprise a statistically significant cluster of pediatric bicycle accidents (Figure 1). Low-income neighborhoods and those near major roadways held the highest risk for pediatric bicycle accidents. Use of helmets was extremely low in the patient population, with high rates of traumatic brain injury. With this information, targeted programs to address high-risk intersections, helmet access, and safety education can be implemented locally

Pediatric Pedestrian Injuries: Striking Too Close to Home

Pediatric pedestrian injuries (PPI) are a major public health concern. This study utilized geospatial analysis to characterize the risk and injury severity of PPI. A retrospective chart review of PPI patients (age < 18) from a level 1 trauma center was performed (2013–2020). A geographic information system geocoded injury location to home and other public landmarks. Incidents were aggregated to zip codes and the Local Indicators of Spatial Association statistic tested for spatial clustering of injury rates per 10,000 children. Predictors for increased injury severity were assessed by logistic regression. PPI encompassed 6% (n = 188) of pediatric traumas. Most patients were black (54%), male (58%), >13 years (56%), and with Medicaid insurance (68%). Nine zip codes comprised a statistically significant cluster of PPI. Nearly half (40%) occurred within a quarter mile of home; 7% occurred at home. Most (65%) PPI occurred within 1 mile of a school, and 45% occurred within a quarter mile of a park. Nearly all (99%) PPI occurred within a quarter mile of a major intersection and/or roadway. Using admission to ICU as a marker for injury severity, farther distance from home (OR 1.060, 95% CI 1.001–1.121, p = 0.045) and age <13 years (3.662, 95% CI 1.854–7.231, p < 0.001) were independent predictors of injury severity. There are significant sociodemographic disparities in PPI. Most injuries occur near patients’ homes and other public landmarks. Multidisciplinary injury prevention collaboration can help inform policymakers, direct local safety programs, and provide a model for PPI prevention at the national level. Level IV. [Display omitted