3,255 research outputs found
Data report for the Siple Coast (Antarctica) project
This report presents data collected during three field seasons of glaciological studies in the Antarctica and describes the methods employed. The region investigated covers the mouths of Ice Streams B and C (the Siple Coast) and Crary Ice Rise on the Ross Ice Shelf. Measurements included in the report are as follows: surface velocity and deformation from repeated satellite geoceiver positions; surface topography from optical levelling; radar sounding of ice thickness; accumulation rates; near-surface densities and temperature profiles; and mapping from aerial photography
Radiation Damage Studies of Silicon Photomultipliers
We report on the measurement of the radiation hardness of silicon
photomultipliers (SiPMs) manufactured by
Fondazione Bruno Kessler in Italy (1 mm and 6.2 mm), Center of
Perspective Technology and Apparatus in Russia (1 mm and 4.4 mm), and
Hamamatsu Corporation in Japan (1 mm). The SiPMs were irradiated using a
beam of 212 MeV protons at Massachusetts General Hospital, receiving fluences
of up to protons per cm with the SiPMs at operating
voltage. Leakage currents were read continuously during the irradiation. The
delivery of the protons was paused periodically to record scope traces in
response to calibrated light pulses to monitor the gains, photon detection
efficiencies, and dark counts of the SiPMs. The leakage current and dark noise
are found to increase with fluence. Te leakage current is found to be
proportional to the mean square deviation of the noise distribution, indicating
the dark counts are due to increased random individual pixel activation, while
SiPMs remain fully functional as photon detectors. The SiPMs are found to
anneal at room temperature with a reduction in the leakage current by a factor
of 2 in about 100 days.Comment: 35 pages, 25 figure
Fundamental Strings in Open String Theory at the Tachyonic Vacuum
We show that the world-volume theory on a D-p-brane at the tachyonic vacuum
has solitonic string solutions whose dynamics is governed by the Nambu-Goto
action of a string moving in (25+1) dimensional space-time. This provides
strong evidence for the conjecture that at this vacuum the full (25+1)
dimensional Poincare invariance is restored. We also use this result to argue
that the open string field theory at the tachyonic vacuum must contain closed
string excitations.Comment: LaTeX file, 16 pages, references and clarification adde
Type 2 Diabetes Prevention in the Real World: Three-year results of the GOAL Lifestyle Implementation Trial
The inheritance of color and horns in Blue-gray cattle II
This bulletin is a sequel to Research Bulletin No. 30 published in 1916. It contains information and a discussion concerning the progeny from the original stock subsequent to that date.
The work of the previous investigators, their results and the conclusions drawn therefrom, are retabulated without details. Additional data are added showing that the recessive whites obtained from the F2 breed true.
The nature of the roan in the Shorthorn is considered. While it is recognized that Wright\u27s criticism of the hypothesis used (Wentworth\u27s) rendered it improbable, yet the fact that two whites when mated to self-colored bulls threw self-colored calves, seems to disprove the hypothesis that roan is the simple heterozygote between self-pigmented and white. Accordingly no conclusions are drawn with respect to roaning.
The relation of these whites with dark points to the similarly marked Wild White Park Cattle of Great Britain is discussed, and the conclusion is drawn that they are of a different genetic composition, the former being recessive and the latter dominant to most colors. It seems probable that the only coat color difference between these whites with dark points and the white Shorthorn lies in the degree of pigmentation in the points. The presence of pigment in the ears shows dominance over the almost complete lack of it.
A white with red points was obtained, as demanded by Lloyd Jones\u27 and Evvard\u27s theory.
Matings of the white with dark points to the almost white Ayrshire reveal that there is no genetic similarity between the two types of white. Data were obtained from these matings, but not in a quantity sufficient to advance or prove any hypothesis.
Detailed tables and descriptions of the new individuals are presented
Diet, nutrition and the prevention of type 2 diabetes
Objectives: The overall objective of this study was to evaluate and provide evidence
and recommendations on current published literature about diet and lifestyle in the
prevention of type 2 diabetes.
Design: Epidemiological and experimental studies, focusing on nutritional
intervention in the prevention of type 2 diabetes are used to make disease-specific
recommendations. Long-term cohort studies are given the most weight as to strength
of evidence available.
Setting and subjects: Numerous clinical trials and cohort studies in low, middle and
high income countries are evaluated regarding recommendations for dietary
prevention of type 2 diabetes. These include, among others, the Finnish Diabetes
Prevention Study, US Diabetes Prevention Program, Da Qing Study; Pima Indian
Study; Iowa Womenâs Health Study; and the study of the US Male Physicians.
Results: There is convincing evidence for a decreased risk of diabetes in adults who are
physically active and maintain a normal body mass index (BMI) throughout
adulthood, and in overweight adults with impaired glucose tolerance who lose weight
voluntarily. An increased risk for developing type 2 diabetes is associated with
overweight and obesity; abdominal obesity; physical inactivity; and maternal diabetes.
It is probable that a high intake of saturated fats and intrauterine growth retardation
also contribute to an increased risk, while non-starch polysaccharides are likely to be
associated with a decreased risk. From existing evidence it is also possible that omega-3 fatty acids, low glycaemic index foods and exclusive breastfeeding may play a
protective role, and that total fat intake and trans fatty acids may contribute to the risk.
However, insufficient evidence is currently available to provide convincing proof.
Conclusions: Based on the strength of available evidence regarding diet and lifestyle in the prevention of type 2 diabetes, it is recommended that a normal weight status in the lower BMI range (BMI 21â23) and regular physical activity be maintained throughout adulthood; abdominal obesity be prevented; and saturated fat intake be less than 7% of the total energy intake
Low-Background gamma counting at the Kimballton Underground Research Facility
The next generation of low-background physics experiments will require the
use of materials with unprecedented radio-purity. A gamma-counting facility at
the Kimballton Underground Research Facility (KURF) has been commissioned to
perform initial screening of materials for radioactivity primarily from
nuclides in the 238U and 232Th decay chains, 40K and cosmic-ray induced
isotopes. The facility consists of two commercial low-background high purity
germanium (HPGe) detectors. A continuum background reduction better than a
factor of 10 was achieved by going underground. This paper describes the
facility, detector systems, analysis techniques and selected assay results.Comment: 7 pages, 7 figures. Submitted to NIM
Glass transition and effective potential in the hypernetted chain approximation
We study the glassy transition for simple liquids in the hypernetted chain
(HNC) approximation by means of an effective potential recently introduced.
Integrating the HNC equations for hard spheres, we find a transition scenario
analogous to that of the long range disordered systems with ``one step replica
symmetry breaking''. Our result agree qualitatively with Monte Carlo
simulations of three dimensional hard spheres.Comment: 7 pages, 7 figures, Revtex fil
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