362 research outputs found
The Use of Odors to Induce Avoidance Behavior in Pine Voles
Commercial orchards, ornamental nurseries, and residential horticulture in North Carolina experience economic losses due to pine vole (Microtus pinetorum) depredation. Predator odors and the herbicide Casoron were tested as potential repellents for pine voles. To test for avoidance behavior, animals were allowed to build a nest in one of two chambers attached to each arm of a Y-maze. The cage containing the nest was treated with either a test repellent compound, methylene chloride (solvent control), or left unmanipulated (control). Animals were categorized as either maintaining or changing nest cage preference between pre-test and test periods. The number of animals that changed cage preference in the control group was compared to the treatment groups. Only the Casoron treatments were significantly different, with approximately 50% of the animals changing preference. The difference in time spent in the nest cage during the pre-test and test periods for the treatment groups were compared to control groups. The Casoron and DTT treatments resulted in significant time differences. These results indicate that Casoron has repellent potential and warrants further investigation into its effectiveness in the field. The predator odors tested showed little promise as repellents
NGC 2419, M92, and the Age Gradient in the Galactic Halo
The WFPC2 camera on HST has been used to obtain deep main sequence photometry
of the low-metallicity ([Fe/H]=-2.14), outer-halo globular cluster NGC 2419. A
differential fit of the NGC 2419 CMD to that of the similarly metal-poor \
standard cluster M92 shows that they have virtually identical principal
sequences and thus the same age to well within 1 Gyr. Since other
low-metallicity clusters throughout the Milky Way halo have this same age to
within the 1-Gyr precision of the differential age technique, we conclude that
the earliest star (or globular cluster) formation began at essentially the same
time everywhere in the Galactic halo throughout a region now almost 200 kpc in
diameter. Thus for the metal-poorest clusters in the halo there is no
detectable age gradient with Galactocentric distance. To estimate the absolute
age of NGC 2419 and M92, we fit newly computed isochrones transformed through
model-atmosphere calculations to the (M_V,V-I) plane, with assumed distance
scales that represent the range currently debated in the literature.
Unconstrained isochrone fits give M_V(RR) = 0.55 \pm 0.06 and a resulting age
of 14 to 15 Gyr. Incorporating the full effects of helium diffusion would
further reduce this estimate by about 1 Gyr. A distance scale as bright as
M_V(RR) = 0.15 for [Fe/H] = -2, as has recently been reported, would leave
several serious problems which have no obvious solution in the context of
current stellar models.Comment: 32 pages, aastex, 9 postscript figures; accepted for publication in
AJ, September 1997. Also available by e-mail from [email protected]
Localization of the dopamine transporter gene, Dat1 , on mouse Chromosome 13
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47009/1/335_2004_Article_BF00292340.pd
Field Blue Stragglers and Related Mass Transfer Issues
This chapter contains my impressions and perspectives about the current state
of knowledge about field blue stragglers (FBS) stars, drawn from an extensive
literature that I searched. I conclude my review of issues that attend FBS and
mass transfer, by a brief enumeration of a few mildly disquieting observational
facts.Comment: Chapter 4, in Ecology of Blue Straggler Stars, H.M.J. Boffin, G.
Carraro & G. Beccari (Eds), Astrophysics and Space Science Library, Springe
Prevalence and Clinical Presentation of Health Care Workers With Symptoms of Coronavirus Disease 2019 in 2 Dutch Hospitals During an Early Phase of the Pandemic
Importance: On February 27, 2020, the first patient with coronavirus disease 2019 (COVID-19) was reported in the Netherlands. During the following weeks, at 2 Dutch teaching hospitals, 9 health care workers (HCWs) received a diagnosis of COVID-19, 8 of whom had no history of travel to China or northern Italy, raising the question of whether undetected community circulation was occurring. Objective: To determine the prevalence and clinical presentation of COVID-19 among HCWs with self-reported fever or respiratory symptoms. Design, Setting, and Participants: This cross-sectional study was performed in 2 teaching hospitals in the southern part of the Netherlands in March 2020, during the early phase of the COVID-19 pandemic. Health care workers employed in the participating hospitals who experienced fever or respiratory symptoms were asked to voluntarily participate in a screening for infection with the severe acute respiratory syndrome coronavirus 2. Data analysis was performed in March 2020. Main Outcomes and Measures: The prevalence of severe acute respiratory syndrome coronavirus 2 infection was determined by semiquantitative real-time reverse transcriptase-polymerase chain reaction on oropharyngeal samples. Structured interviews were conducted to document symptoms for all HCWs with confirmed COVID-19. Results: Of 9705 HCWs employed (1722 male [18%]), 1353 (14%) reported fever or respiratory symptoms and were tested. Of those, 86 HCWs (6%) were infected with severe acute respiratory syndrome coronavirus 2 (median age, 49 years [range, 22-66 years]; 15 [17%] male), representing 1% of all HCWs employed. Most HCWs experienced mild disease, and only 46 (53%) reported fever. Eighty HCWs (93%) met a case definition of fever and/or coughing and/or shortness of breath. Only 3 (3%) of the HCWs identified through the screening had a history of travel to China or northern Italy, and 3 (3%) reported having been exposed to an inpatient with a known diagnosis of COVID-19 before the onset of symptoms. Conclusions and Relevance: Within 2 weeks after the first Dutch case was detected, a substantial proportion of HCWs with self-reported fever or respiratory symptoms were infected with severe acute respiratory syndrome coronavirus 2, likely as a result of acquisition of the virus in the community during the early phase of local spread. The high prevalence of mild clinical presentations, frequently not including fever, suggests that the currently recommended case definition for suspected COVID-19 should be used less stringently
Maternal effects on anogenital distance in a wild marmot population
Peer reviewedPublisher PD
Analysis of Male Pheromones That Accelerate Female Reproductive Organ Development
Male odors can influence a female's reproductive physiology. In the mouse, the odor of male urine results in an early onset of female puberty. Several volatile and protein pheromones have previously been reported to each account for this bioactivity. Here we bioassay inbred BALB/cJ females to study pheromone-accelerated uterine growth, a developmental hallmark of puberty. We evaluate the response of wild-type and mutant mice lacking a specialized sensory transduction channel, TrpC2, and find TrpC2 function to be necessary for pheromone-mediated uterine growth. We analyze the relative effectiveness of pheromones previously identified to accelerate puberty through direct bioassay and find none to significantly accelerate uterine growth in BALB/cJ females. Complementary to this analysis, we have devised a strategy of partial purification of the uterine growth bioactivity from male urine and applied it to purify bioactivity from three different laboratory strains. The biochemical characteristics of the active fraction of all three strains are inconsistent with that of previously known pheromones. When directly analyzed, we are unable to detect previously known pheromones in urine fractions that generate uterine growth. Our analysis indicates that pheromones emitted by males to advance female puberty remain to be identified
Isolation of bacterial extrachromosomal DNA from human dental plaque associated with periodontal disease,using transposonaided capture (TRACA)
The human oral cavity is host to a complex microbial community estimated to comprise > 700 bacterial species, of which at least half are thought to be not yet cultivable in vitro. To investigate the plasmids present in this community, we used a transposon-aided capture system, which allowed the isolation of plasmids from human oral supra- and subgingival plaque samples. Thirty-two novel plasmids and a circular molecule that could be an integrase-generated circular intermediate were isolated
The Functional DRD3 Ser9Gly Polymorphism (rs6280) Is Pleiotropic, Affecting Reward as Well as Movement
Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3) gene (ser9gly, rs6280) on reward-associated dopamine (DA) release in the striatum. Twenty-six healthy controls (HCs) and 10 unmedicated subjects with major depressive disorder (MDD) completed two positron emission tomography (PET) scans with [11C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition) and on another occasion subjects completed a gambling task (reward condition). A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release) in the middle (anterior) caudate (p<0.01) and the ventral striatum (p<0.05). The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis
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