3,143 research outputs found
Decreasing initial telomere length in humans intergenerationally understates age-associated telomere shortening
Telomere length shortens with aging, and short telomeres have been linked to a wide variety of pathologies. Previous studies suggested a discrepancy in age-associated telomere shortening rate estimated by cross-sectional studies versus the rate measured in longitudinal studies, indicating a potential bias in cross-sectional estimates. Intergenerational changes in initial telomere length, such as that predicted by the previously described effect of a father's age at birth of his offspring (FAB), could explain the discrepancy in shortening rate measurements. We evaluated whether changes occur in initial telomere length over multiple generations in three large datasets and identified paternal birth year (PBY) as a variable that reconciles the difference between longitudinal and cross-sectional measurements. We also clarify the association between FAB and offspring telomere length, demonstrating that this effect is substantially larger than reported in the past. These results indicate the presence of a downward secular trend in telomere length at birth over generational time with potential public health implications
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Microhabitat associations of northern flying squirrels in burned and thinned forest stands of the Sierra Nevada
Prescribed burning and mechanical thinning are used to manage fuels within
many western North American forest ecosystems, but few studies have examined the relative
impacts of these treatments on forest wildlife. We sampled northern flying squirrels
(Glaucomys sabrinus) and microhabitat variables in burned, thinned and control stands of
mixed-conifer forest of the southern Sierra Nevada at the Teakettle Experimental Forest. We
used this information to determine the effects of burning and thinning on the microhabitat
associations of flying squirrels. Across pretreatment stands, the probability of flying squirrel
capture increased with decreasing distance to a perennial creek and increasing litter depth.
The probability of flying squirrel capture also was greater with increased canopy cover in
thinned stands and increased litter depth in burned stands. Greater canopy cover may provide
protection from predators, thicker litter layers may harbor a greater abundance of
truffles, a primary food of northern flying squirrels, and creeks may provide squirrels with
food sources, drinking water and nest trees. Results from this study underscore the need
for more information on the effects of forest management on northern flying squirrels
near the southern extent of the speciesâ geographic range
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Microhabitat associations of northern flying squirrels in burned and thinned forest stands of the Sierra Nevada
Prescribed burning and mechanical thinning are used to manage fuels within many western North American forest ecosystems, but few studies have examined the relative impacts of these treatments on forest wildlife. We sampled northern flying squirrels (Glaucomys sabrinus) and microhabitat variables in burned, thinned and control stands of mixed-conifer forest of the southern Sierra Nevada at the Teakettle Experimental Forest. We used this information to determine the effects of burning and thinning on the microhabitat associations of flying squirrels. Across pretreatment stands, the probability of flying squirrel capture increased with decreasing distance to a perennial creek and increasing litter depth. The probability of flying squirrel capture also was greater with increased canopy cover in thinned stands and increased litter depth in burned stands. Greater canopy cover may provide protection from predators, thicker litter layers may harbor a greater abundance of truffles, a primary food of northern flying squirrels, and creeks may provide squirrels with food sources, drinking water and nest trees. Results from this study underscore the need for more information on the effects of forest management on northern flying squirrels near the southern extent of the speciesâ geographic range
CHILES: HI morphology and galaxy environment at z=0.12 and z=0.17
We present a study of 16 HI-detected galaxies found in 178 hours of
observations from Epoch 1 of the COSMOS HI Large Extragalactic Survey (CHILES).
We focus on two redshift ranges between 0.108 <= z <= 0.127 and 0.162 <= z <=
0.183 which are among the worst affected by radio frequency interference (RFI).
While this represents only 10% of the total frequency coverage and 18% of the
total expected time on source compared to what will be the full CHILES survey,
we demonstrate that our data reduction pipeline recovers high quality data even
in regions severely impacted by RFI. We report on our in-depth testing of an
automated spectral line source finder to produce HI total intensity maps which
we present side-by-side with significance maps to evaluate the reliability of
the morphology recovered by the source finder. We recommend that this become a
common place manner of presenting data from upcoming HI surveys of resolved
objects. We use the COSMOS 20k group catalogue, and we extract filamentary
structure using the topological DisPerSE algorithm to evaluate the \hi\
morphology in the context of both local and large-scale environments and we
discuss the shortcomings of both methods. Many of the detections show disturbed
HI morphologies suggesting they have undergone a recent interaction which is
not evident from deep optical imaging alone. Overall, the sample showcases the
broad range of ways in which galaxies interact with their environment. This is
a first look at the population of galaxies and their local and large-scale
environments observed in HI by CHILES at redshifts beyond the z=0.1 Universe.Comment: 23 pages, 12 figures, 1 interactive 3D figure, accepted to MNRA
Active compounds and distinctive sensory features provided by American ginseng (Panax quinquefolius L.) extract in a new functional milk beverage
American ginseng (Panax quinquefolius L.) has recognized neurocognitive effects, and a ginsenoside-rich extract of the root of the plant has been shown to improve cognitive functions in young adults. This study aimed at assessing the chemical and sensory profiles of a UHT-treated, low-lactose functional milk containing American ginseng. Individual ginsenosides in the milk were analyzed by HPLC. Descriptive sensory analysis was performed by a trained panel to quantitatively document sensory changes resulting from the addition of ginseng and the UHT process on flavored and unflavored milks. Consumer acceptance of the product was also investigated. Total ginsenoside content in the UHT-treated milk enriched with the ginseng extract after UHT process treatment was 7.52. mg/100. g of milk, corresponding to a recovery of 67.6% compared with the content in the unprocessed extract. The intake of 150 to 300. mL of this ginseng-enriched milk provides the amount of total ginsenosides (11.5 to 23. mg) necessary to improve cognitive function after its consumption. Both the presence of ginsenosides and their thermal treatment affected some sensory properties of the milk, most notably an increase in bitterness and metallic taste, the appearance of a brownish color, and a decrease in milky flavor. Levels of brown color, bitterness, and metallic taste were highest in the industrially processed ginseng-enriched milk. The bitterness attributable to ginseng extract was reduced by addition of vanilla flavor and sucralose. A consumer exploratory study revealed that a niche of consumers exists who are willing to consume this type of product.The financial support of the Ministry of Science and Innovation of Spain (Madrid, Spain) for the project SENIFOOD (CENIT Programme) and for the contract with A. TĂĄrrega (Juan de la Cierva Programme) is acknowledged. We gratefully acknowledge Juan Duato Aguilar, from Naturex Spain S.L. (Quart de Poblet, Spain), for his valuable technical support
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Hypogeous ectomycorrhizal fungal species on roots and in small mammal diet in a mixed-conifer forest
The purpose of this study was to estimate the portion of an ectomycorrhizal (ECM) fungi root
community with a hypogeous fruiting habit. We used molecular methods (DNA sequence analysis of the
internally transcribed spacer [ITS] region of rDNA) to compare three viewpoints: ECM fungi on the roots in a
southern Sierra Nevada Abies-dominated old-growth forest, fungi in scat samples collected from small mammals
in the same forest, and hypogeous sporocarps found throughout the Sierra Nevada. We found that hypogeous
taxa accounted for a minimum of 21% of the species and 25â40% of the dry root biomass of all samples. This
estimate is two to three times greater than estimates from previous studies. This difference may be due to
methodological advantages of this study, but may also be related to conditions in dry forests typical of western
North America where prolonged drought may favor this form of fruiting. Although molecular analysis of scat
samples did not add to our view of the ECM roots, we readily isolated sequences from Rhizopogon species. From
these results we inferred that two species, R. occidentalis and R. olivaceotinctus, are represented primarily in the
spore bank and may be dependent on substantial disturbance to become abundant on roots. FOR. SCI. 51(3):
243â254.Keywords: Fecal pellet, Community structure, Mycophag
Medium-spin states in neutron-rich 83As and 81As
The 83,81 As nuclei have been produced as fission fragments in the fusion reaction 18Oâ+â208Pb at 85 MeV bombarding energy and studied with the Euroball array. Medium-spin states of 83,81 As have been established up to âŒ3.5 MeV excitation energy. From angular correlation analysis, spin values have been assigned to most of the 81 As excited states. The behaviors of the yrast structures identified in this work are discussed in comparison with the general features known in the mass region. Then they are compared to the results of two theoretical approaches: the "rotor + quasiparticle" for 81 As and the shell model using the effective interactions JUN45 for 83,81 As
The first determination of Generalized Polarizabilities of the proton by a Virtual Compton Scattering experiment
Absolute differential cross sections for the reaction (e+p -> e+p+gamma) have
been measured at a four-momentum transfer with virtuality Q^2=0.33 GeV^2 and
polarization \epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum
of the outgoing photon in the photon-proton center of mass frame. The
experiment has been performed with the high resolution spectrometers at the
Mainz Microtron MAMI. From the photon angular distributions, two structure
functions which are a linear combination of the generalized polarizabilities
have been determined for the first time.Comment: 4 pages, 3 figure
Parameter estimation of spinning binary inspirals using Markov-chain Monte Carlo
We present a Markov-chain Monte-Carlo (MCMC) technique to study the source
parameters of gravitational-wave signals from the inspirals of stellar-mass
compact binaries detected with ground-based gravitational-wave detectors such
as LIGO and Virgo, for the case where spin is present in the more massive
compact object in the binary. We discuss aspects of the MCMC algorithm that
allow us to sample the parameter space in an efficient way. We show sample runs
that illustrate the possibilities of our MCMC code and the difficulties that we
encounter.Comment: 10 pages, 2 figures, submitted to Classical and Quantum Gravit
Perceptions of institutional complexity and lobbyistsâ decisions to join lobbying coalitions â evidence from the European Union context
YesWe use data from in-depth interviews with business lobbyists in Brussels to
investigate why they choose to join lobbying coalitions. We find that
lobbyists face two competing institutional incentives. First, they are
confronted with incentives to ally with other European organisations,
develop multilateral policy messages, and communicate messages to the
Commission and the Parliament. Simultaneously, they face inducements to
join narrower coalitions, develop bilateral policy messages, and direct
those messages at the Council. Lobbyistsâ receptivity to these incentives â
and thus their choices of lobbying coalitions â differs with their age,
educational background, and with the type and ownership structure of the
organisations they represent. Combined, our findings contribute to the
limited, mainly American literature on interest coalitions by demonstrating
that lobbyists operate in complex institutional environments, and that their
interpretations of and reactions to institutional complexity are shaped by
individual- and organisational-level factors
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