Body Position,Age and Mass Effect of Adiposity on Adipose Tissue Red Cell Flux in Morbid Obesity

Objective: To measure red cell flux of adipose tissue in morbidly obese patients' pannus in the upright and supine position to determine factors which would render the lower pannus susceptible to ischemic necrosis. Design: A cohort study of morbidly obese subjects without ischemic necrosis. Setting: University teaching hospital. Patients: Twenty-three consecutive morbidly obese patients referred for gastroplasty. Measurements: Red cell flux, measured as RMS voltage by a laser Doppler velocimeter. An optical fiber with a tip diameter of 250μ was inserted into the upper and lower pannus and output recorded in the upright and supine positions. Other variables recorded were age, BMI, blood pressure and serum lipids. Results: Adipose tissue red cell flux demonstrates considerable spatial and temporal heterogeneity from subject to subject and in various locations in the pannus. No differences in red cell flux were detected in response to change in position. However, regression analysis demonstrated that the gradient between the upper and lower abdomen in the supine position was increasingly positive with age and in the upright position it was increasingly positive with increasing weight or BMI. Conclusions: These data suggest that red cell flux is heterogeneously distributed in the abdominal pannus and is not greatly influenced by body position. However, with increasing age and adiposity there is a gradient for decreased red cell flux to the lower portion of the pannus. This may be a factor in rendering this part of the pannus prone to ischemic fat necrosis.     

Effects of posture, hypotension and locally applied vasoconstriction on the middle ear microcirculation in anaesthetized humans

Studies by laser-Doppler flowmetry of middle ear microcirculation changes induced by physical and chemical stimuli in the animal have only recently been made. This prospective study, performed in humans, was designed to compare the effects of a postural manoeuvre (headup tilt 30°), hypotension and locally applied vasoconstriction on middle ear blood flow during anaesthesia. Circulatory changes provoked by a headup tilt of 30°, and successive intravenous boluses of potent vasodilators, were compared with circulatory changes provoked by locally applied adrenaline, in ten healthy patients in good physical states undergoing middle ear surgical repair. Heart rate and direct arterial pressure were continuously recorded via a radial artery cannula. Middle ear blood flow was continuously recorded via a laser-Doppler probe placed on the promontorium cavi tympani. Metabolic parameters (partial pressure of O₂ and CO₂ in arterial blood, pH, arterial lactate concentrations) and arterial concentrations of propofol were measured just before and just after the experiment. Headup tilt did not modify heart rate, mean arterial pressure or middle ear blood flow. Vasodilators (nicardipine, nitroprusside, nitroglycerin) provoked a fall in arterial pressure (P<0.0001,P<0.0001,P<0.019, respectively), but did not induce any significant variations in heart rate; variations occurred in middle ear blood flow (P>0.05, not significant) which were different according to patients and agents. Locally applied adrenaline provoked a fall in the middle ear blood flow (P<0.0012), with no effect on heart rate and arterial pressure. There were no significant changes in metabolic values, or propofol serum concentrations. The behaviour of the middle ear blood flow submitted to hypotension, posture, or to vasoconstriction could be related to counteracting regulatory responses and/or to direct vascular effects.     

Productivity of outdoor algal cultures in unstable weather conditions

In the outdoor cyclic fed batch cultures of Chlorella pyrenoidosa, some typical growth kinetics patterns in unstable weather conditions were observed. On cloudy days, the biomass output rate (R) was low, but the bioenergetic growth yield (Y) was generally high. In the cloudy morning-sunny afternoon condition, the values of Y were low, especially in the afternoon. In the sunny morning-cloudy afternoon condition, both R and Y were high. A few very high short-term Y values were measured during the cloudy the cloudy afternoon. (c) 1993 Wiley & Sons, Inc.     

Cardiovascular responses to sustained maximal isometric contractions of the finger flexors

This study investigated cardiovascular responses to 2 min sustained submaximal (20% MVC) and maximal (100% MVC) voluntary isometric contractions of the finger flexors in healthy young women. Cardiovascular variables investigated were: heart rate (f _c), mean arterial pressure ( _a), and stroke volume (SV). Doppler echocardiography was used to estimate SV from measures of aortic diameter (AD) and time-velocity integrals. Preliminary studies indicated that AD did not change significantly after 2 min sustained 100% MVC. Therefore, pre-exercise AD values were used to calculate SV before, during and after exercise. During the 2-min 100% MVC period, f _c and _aincreased significantly during the first 30 s of contraction. f _c then remained constant during the remainder of the 2-min contraction period, while _acontinued to rise. SV did not change significantly during the 100% MVC task but increased significantly during recovery from sustained 100% MVC. The data suggest that the magnitude of cardiovascular responses to isometric exercise is dependent on the specific task performed, and that there is a different pattern of response for f _c, _a, and SV during 20% and 100% MVC tasks. Unlike f _c and _a, SV did not change significantly during isometric exercise, but increased significantly after sustained 100% MVC.     

The evaluation of corpus luteum blood flow using color-flow Doppler ultrasound for early pregnancy diagnosis in bovine embryo recipients

The objective of this experiment was to evaluate corpus luteum blood flow (CLBF) as an early indicator of pregnancy status in bovine embryo recipients. Fifty crossbred beef cows were submitted to embryo transfer on Day 7 after estrus. On Days 7, 11, 13, 15, 17, 19, 21, 26, 33, and 40, a blood sample was taken, the CL examined using a color-flow Doppler ultrasound scanner, and video was recorded of each scanning session. Ultrasound data were grouped by the first day progesterone concentrations were <1 ng/mL (indicating early embryo loss, EEL) through Day 21 (EEL-17, n = 3; EEL-19, n = 9; EEL-21, n = 3), absence of an embryo on Days 26, 33, or 40 (late embryo loss; LEL; n = 12), or remained pregnant (P; n = 23). The first decrease in CLBF of EEL-17, EEL-19, and EEL-21 cows compared to P cows occurred on Days 17, 19, and 21, respectively (P < 0.05). There was no difference in CLBF between LEL and P cows on Days 17, 19, and 21. Six evaluators diagnosed pregnancy from randomized video clips on Days 17, 19, and 21. Evaluators made more (P < 0.004) correct diagnoses on Day 19 than Day 17. Sensitivity (82.9 ± 10.1%) was not affected by day. From Days 17 to 19, diagnostic specificity increased (P = 0.046) from 43.2 ± 3.0 to 54.3 ± 3.0% but remained unchanged thereafter. Due to low specificity and sensitivity, evaluation of CLBF alone was insufficient for early pregnancy diagnosis.     

Survivorship and Spatial Patterns of an Urban Population of Texas Horned Lizards

Habitat fragmentation has negative consequences on threatened and endangered species by creating isolated populations. The Texas horned lizard (Phrynosoma cornutum) is experiencing population declines and localized extirpations throughout its range and has been classified as a species of greatest conservation need in Oklahoma, USA. Younger age classes have been poorly studied but may be vital to the stability of remaining populations. To address gaps in knowledge concerning subadult (hatchling and juvenile) morphometrics, survivorship, and home range sizes, we studied 2 cohorts of subadults, for 2 years each, covering their hatching and juvenile years (2016–2019). We used a combination of radio-telemetry and novel harmonic radar methodology to study a closed population of Texas horned lizards in 15 ha of native grassland at Tinker Air Force Base, Oklahoma. Population abundance for adults and juveniles was estimated as 56.5 ± 5.5 lizards and density as 7.96 lizards/ha. Our lowest estimates of survival indicated an average survival probability for the hatchling life stage of 0.285 (95% CI = 0.15–0.44), which is lower than for adults on the site. Average home range size increased from hatchling to adult life stages. Our results will have an immediate effect on the planning and assessment of ongoing headstart and management programs for Texas horned lizards. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

陕西长武玉米降水指数保险设计

天气指数保险能有效规避传统农业保险的弊端。本研究基于陕西长武长序列产量数据和气象数据,采用统计分析的方法进行种植面积、产量、单产、趋势产量、相对气象产量以及玉米生育期需供水的分析;采用基于损失的风险评估方法评价种植风险;采用基于Logistic模型的费率厘定方法进行纯费率厘定;根据降水指数和减产率的相关性,设计降水指数;采用投影寻踪的方法设计降水指数赔付方案。结果表明:长武玉米种植面积、产量、单产、趋势产量以及相对气象产量都呈现出增加趋势;生育期平均需水650 mm,降水434mm,亏缺216 mm;从4月下旬到8月下旬,玉米呈现出水分亏缺的状态,7月中旬抽雄期水分亏缺最多,为33.65 mm;9月出现微弱的水分盈余;1994、1995和1997年为减产年,减产率分别为14%、20%和44%,相应降水距平分别为-42.44%、-47.72%和-29.71%;玉米种植轻、中、重和巨灾的发生概率分别是7.49%、3.40%、1.43%和1%;玉米降水指数保险纯费率为2.92%;生育期内旬降水(阈值为40 mm)累积值指定为玉米降水指数,并以降水指数为变量进行分段赔付。本研究剖析了长武玉米种植状况和干旱灾害,并设计了玉米的降水指数保险产品,为长武玉米农业保险提供了新的选择,对解决农业保险目前的困境具有重要的意义。     

Spatial co‐localisation of extreme weather events: a clear and present danger

Extreme weather events have become a dominant feature of the narrative surrounding changes in global climate with large impacts on ecosystem stability, functioning and resilience; however, understanding of their risk of co‐occurrence at the regional scale is lacking. Based on the UK Met Office’s long‐term temperature and rainfall records, we present the first evidence demonstrating significant increases in the magnitude, direction of change and spatial co‐localisation of extreme weather events since 1961. Combining this new understanding with land‐use data sets allowed us to assess the likely consequences on future agricultural production and conservation priority areas. All land‐uses are impacted by the increasing risk of at least one extreme event and conservation areas were identified as the hotspots of risk for the co‐occurrence of multiple event types. Our findings provide a basis to regionally guide land‐use optimisation, land management practices and regulatory actions preserving ecosystem services against multiple climate threats.     

A place to land: spatiotemporal drivers of stopover habitat use by migrating birds

Migrating birds require en route habitats to rest and refuel. Yet, habitat use has never been integrated with passage to understand the factors that determine where and when birds stopover during spring and autumn migration. Here, we introduce the stopover‐to‐passage ratio (SPR), the percentage of passage migrants that stop in an area, and use 8 years of data from 12 weather surveillance radars to estimate over 50% SPR during spring and autumn through the Gulf of Mexico and Atlantic coasts of the south‐eastern US, the most prominent corridor for North America’s migratory birds. During stopovers, birds concentrated close to the coast during spring and inland in forested landscapes during autumn, suggesting seasonal differences in habitat function and highlighting the vital role of stopover habitats in sustaining migratory communities. Beyond advancing understanding of migration ecology, SPR will facilitate conservation through identification of sites that are disproportionally selected for stopover by migrating birds.