This study, designed to determine the relative degree of testosterone deficiency, estradiol deficiency, or both at which undesirable bodily changes occur, showed that some features of male ...hypogonadism are due to both androgen deficiency and estrogen deficiency.
Testosterone therapy is prescribed for millions of men each year, and the number is increasing rapidly. Prescription sales of testosterone increased by 500% in the United States between 1993 and 2000.
1
Most testosterone prescriptions are written to treat nonspecific symptoms, such as fatigue or sexual dysfunction, when accompanied by testosterone levels below the laboratory reference range. Currently, testosterone levels that are at least 2 SD below the mean value for healthy young adults are classified as low.
1
,
2
Although convenient, this classification fails to consider the physiological consequences of specific testosterone levels.
More than 80% of circulating estradiol in men . . .
Co-infection is an underappreciated phenomenon in contemporary disease ecology despite its ubiquity and importance in nature. Viruses, and other co-infecting agents, can interact in ways that shape ...host and agent communities, influence infection dynamics, and drive evolutionary selective pressures. Bats are host to many viruses of zoonotic potential and have drawn increasing attention in their role as wildlife reservoirs for human spillover. However, the role of co-infection in driving viral transmission dynamics within bats is unknown. Here, we systematically review peer-reviewed literature reporting viral co-infections in bats. We show that viral co-infection is common in bats but is often only reported as an incidental finding. Biases identified in our study database related to virus and host species were pre-existing in virus studies of bats generally. Studies largely speculated on the role co-infection plays in viral recombination and few investigated potential drivers or impacts of co-infection. Our results demonstrate that current knowledge of co-infection in bats is an ad hoc by-product of viral discovery efforts, and that future targeted co-infection studies will improve our understanding of the role it plays. Adding to the broader context of co-infection studies in other wildlife species, we anticipate our review will inform future co-infection study design and reporting in bats. Consideration of detection strategy, including potential viral targets, and appropriate analysis methodology will provide more robust results and facilitate further investigation of the role of viral co-infection in bat reservoirs.
Abstract
The California Current System is thought to be particularly vulnerable to ocean acidification, yet pH remains chronically undersampled along this coast, limiting our ability to assess the ...impacts of ocean acidification. To address this observational gap, we integrated the Deep-Sea-DuraFET, a solid-state pH sensor, onto a Spray underwater glider. Over the course of a year starting in April 2019, we conducted seven missions in central California that spanned 161 glider days and >1600 dives to a maximum depth of 1000 m. The sensor accuracy was estimated to be ± 0.01 based on comparisons to discrete samples taken alongside the glider (
n
= 105), and the precision was ±0.0016. CO
2
partial pressure, dissolved inorganic carbon, and aragonite saturation state could be estimated from the pH data with uncertainty better than ± 2.5%, ± 8
μ
mol kg
−1
, and ± 2%, respectively. The sensor was stable to ±0.01 for the first 9 months but exhibited a drift of 0.015 during the last mission. The drift was correctable using a piecewise linear regression based on a reference pH field at 450 m estimated from published global empirical algorithms. These algorithms require accurate O
2
as inputs; thus, protocols for a simple predeployment air calibration that achieved accuracy of better than 1% were implemented. The glider observations revealed upwelling of undersaturated waters with respect to aragonite to within 5 m below the surface near Monterey Bay. These observations highlight the importance of persistent observations through autonomous platforms in highly dynamic coastal environments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
Exertional rhabdomyolysis (ER) is on the rise among service members and high school and college athletes. Reported risk factors for ER include fitness level, sudden increase in exercise ...intensity and duration, and eccentric predominant exercise. This study examined an ER cluster among Reserve Officer Training Corps cadets who participated in a mandatory, timed, extreme conditioning program (ECP) workout. Forty-four cadets participated in this ECP; 11 were subsequently hospitalized with ER. Thirty-five cadets, including all who developed ER, completed a questionnaire to assess ECP times, prior fitness scores, and other ER risk factors. Cadets completed the ECP workout as individuals or in teams. Nine of 29 (31%) individual and two of 15 (13%) team participants were hospitalized with ER. Among the cadets, no associations were noted between hospitalization for ER and finish time, previous fitness scores, or dietary supplement use. The relative risk of developing ER was significantly increased in those who consumed alcohol in the week preceding the ECP (RR = 4.20; 95% CI 1.95, 9.03). In this cohort of Reserve Officer Training Corps cadets, an ECP resulted in a high rate of hospitalization for ER. Contrary to reported ER risk factors, higher baseline fitness was not protective. Rather, cadet knowledge that ECP performance was strongly linked to final cadet ranking greatly influenced intensity of effort.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Low-frequency sound from large vessels is a major, global source of ocean noise that can interfere with acoustic communication for a variety of marine animals. Changes in vessel activity provide ...opportunities to quantify relationships between vessel traffic levels and soundscape conditions in biologically important habitats. Using continuous deep-sea (890 m) recordings acquired ∼20 km (closest point of approach) from offshore shipping lanes, we observed reduction of low-frequency noise within Monterey Bay National Marine Sanctuary (California, United States) associated with changes in vessel traffic during the onset of the COVID-19 pandemic. Acoustic modeling shows that the recording site receives low-frequency vessel noise primarily from the regional shipping lanes rather than via the Sound Fixing and Ranging (SOFAR) channel. Monthly geometric means and percentiles of spectrum levels in the one-third octave band centered at 63 Hz during 2020 were compared with those from the same months of 2018–2019. Spectrum levels were persistently and significantly lower during February through July 2020, although a partial rebound in ambient noise levels was indicated by July. Mean spectrum levels during 2020 were more than 1 dB re 1 μPa
2
Hz
–1
below those of a previous year during 4 months. The lowest spectrum levels, in June 2020, were as much as 1.9 (mean) and 2.4 (25% exceedance level) dB re 1 μPa
2
Hz
–1
below levels of previous years. Spectrum levels during 2020 were significantly correlated with large-vessel total gross tonnage derived from economic data, summed across all California ports (
r
= 0.81,
p
< 0.05; adjusted
r
2
= 0.58). They were more highly correlated with regional presence of large vessels, quantified from Automatic Identification System (AIS) vessel tracking data weighted according to vessel speed and modeled acoustic transmission loss (
r
= 0.92,
p
< 0.01; adjusted
r
2
= 0.81). Within the 3-year study period, February–June 2020 exhibited persistently quiet low-frequency noise and anomalously low statewide port activity and regional large-vessel presence. The results illustrate the ephemeral nature of noise pollution by documenting how it responds rapidly to changes in offshore large-vessel traffic, and how this anthropogenic imprint reaches habitat remote from major ports and shipping lanes.
Abstract
Many fixed oceanographic instruments and observing systems are deployed in the water column or on the seafloor for extended periods of time without any expression at the sea surface. To ...routinely communicate with such subsurface instruments in the deep ocean, here a system is presented that uses underwater gliders and commercially available acoustic modems for this task and its use is demonstrated with subsurface moorings and inverted echo sounders plus bottom pressure sensor (PIES). One recent glider mission spent 31 days in data retrieval dives, capturing 2 MB of error-free subsurface data. To acquire this volume, a total of 2.65 MB (including all retransmissions) were sent, with a success rate of 75%. A model for the energy usage of each phase of modem function was derived from laboratory measurements. While the model predicts that the glider would expend 0.21 J to acquire each data byte, the actual consumption of the glider in the field is 0.49 J byte−1. The inefficiency is due to overhead associated with establishment of the acoustic link and with the resending of data that is received with errors. Including all the time for negotiating the acoustic link and for the retransmission of erroneous data, the net data throughput are around 3 bytes s−1 in spite of the modem operating at 140 to 600 baud. Even with these limitations, the technique has shown to be useful and is being utilized routinely in a research project in the California Current to obtain data from horizontal distances up to 7 km from an instrument at depths up to 4000 m, transferring on average 6 kB of data in a day of acoustic communications.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
An exploratory study of applicants who rejected admission to the Texas Academy of Mathematics and Science (TAMS) is described in this article. TAMS is a residential early college entry program at the ...University of North Texas in Denton. Up to 600 mathematically talented sophomores apply to TAMS each year and among the 200 selectees, a predictable 10% to 15% will decline admission and remain in high school. Over 9 years, decliners responded to surveys asking why they rejected offers they had vigorously pursued. Respondents indicated their dissonance sprang mostly from preoccupation with extracurricular pursuits, reluctance to leave family and friends, and reassessments of their preparedness for early college entry and science, technology, engineering, and mathematics (STEM) careers. Several interventions are offered to help prospects make informed decisions before applying. Findings may provide insights to guide enrollment policies at other accelerative programs.
The diet of the extinct European cave bear, Ursus spelaeus, has widely been debated. Diverging from the extant brown bear (Ursus arctos) approximately 1.2 million years ago, the cave bear is one of ...the most ubiquitous fossil bears occurring in Europe during the Middle and Late Pleistocene. Early morphological studies suggested that the cave bear was likely specialized on processing tough and/or abrasive foods, while later two-dimensional low-magnification microwear studies suggested that they were omnivorous and may have consumed more bone than U. arctos. Here, we used dental microwear texture analysis (DMTA) to further interpret the diet of the cave bear. Microscopic wear features were assessed and compared to modern ursids, including the cave bears' closest living relative, U. arctos. Results suggest that U. spelaeus consumed a diet with a diversity of textural properties, similar to most other bears and only distinguishable from the hyper-carnivorous polar bear (Ursus maritimus). Further, only U. maritimus can be distinguished from all bear species here examined (i.e., the giant panda bear, Ailuropoda melanoleuca; sun-bear, Ursus malayanus; spectacled bear, Tremarctos ornatus; American black bear, Ursus americanus; and U. arctos), with significantly greater area-scale fractal complexity (Asfc) of microwear surfaces. The DMTA of A. melanoleuca also has significantly lower Asfc than T. ornatus and U. americanus, consistent with observed dietary behavior. As modern bears vary their diets seasonally and across their range, it may be difficult to characterize the dietary ecology of extinct bears using dental microwear alone. Nevertheless, DMTA here demonstrates that U. spelaeus had a diet distinct from the hyper-carnivorous U. maritimus and instead likely consumed food with textural properties most similar to other herbivorous/omnivorous bears. Lastly, the European cave bear and North American giant short-faced bear (Arctodus simus) may have had similar diets as evident from DMTA, with U. spelaeus potentially eating tougher food items.
Four pigeons performed a simultaneous matching‐to‐sample (MTS) task involving two samples and two comparisons that differed in their pixel density and luminance. After a long history of reinforcers ...for correct responses after both samples, 15 conditions arranged either continuous reinforcement of correct responses after Sample 1 and extinction for all responses after Sample 2, or vice versa. The sample after which correct responses were reinforced alternated across successive conditions. The disparity between the samples and the disparity between the comparisons were varied independently across conditions in a quasifactorial design. Contrary to predictions of extant quantitative models, which assume that MTS tasks involve two 3‐term contingencies of reinforcement, matching accuracies were not at chance levels in these conditions, comparison–selection ratios differed after the two samples, and effects on matching accuracies of both sample disparity and comparison disparity were observed. These results were, however, consistent with ordinal and sometimes quantitative predictions of Jones' (2003) theory of stimulus and reinforcement effects in MTS tasks. This theory asserts that MTS tasks involve four‐term contingencies of reinforcement and that any tendency to select one comparison more often than the other over a set of trials reflects meaningful differences between comparison‐discrimination accuracies after the two samples.
The Texas Academy of Mathematics and Science (TAMS) is a publicly financed, residential early college entrance institute at the University of North Texas at Denton. Created in 1987, TAMS enables ...high-achieving students planning STEM careers to complete their last 2 years of high school simultaneously with their first 2 years of college. Admission is selective, and students pay no tuition or book costs. Students must complete a rigorous curriculum of biology, chemistry, physics, mathematics, and humanities. The academy offers intramural athletics, a variety of clubs and organizations, and mentor-guided research opportunities that can lead to prestigious awards and scholarships. Graduates earn a high school diploma and at least 57 transferable college credits—enough to enter many universities 2 years advanced. Now in its third decade, the academy continues to help expand the supply of skilled domestic mathematicians, engineers, and scientists.
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