4,241 research outputs found
Cancer incidence in British vegetarians
Background:
Few prospective studies have examined cancer incidence among vegetarians.
Methods:
We studied 61 566 British men and women, comprising 32 403 meat eaters, 8562 non-meat eaters who did eat fish ('fish eaters') and 20 601 vegetarians. After an average follow-up of 12.2 years, there were 3350 incident cancers of which 2204 were among meat eaters, 317 among fish eaters and 829 among vegetarians. Relative risks (RRs) were estimated by Cox regression, stratified by sex and recruitment protocol and adjusted for age, smoking, alcohol, body mass index, physical activity level and, for women only, parity and oral contraceptive use.
Results:
There was significant heterogeneity in cancer risk between groups for the following four cancer sites: stomach cancer, RRs (compared with meat eaters) of 0.29 (95% CI: 0.07â1.20) in fish eaters and 0.36 (0.16â0.78) in vegetarians, P for heterogeneity=0.007; ovarian cancer, RRs of 0.37 (0.18â0.77) in fish eaters and 0.69 (0.45â1.07) in vegetarians, P for heterogeneity=0.007; bladder cancer, RRs of 0.81 (0.36â1.81) in fish eaters and 0.47 (0.25â0.89) in vegetarians, P for heterogeneity=0.05; and cancers of the lymphatic and haematopoietic tissues, RRs of 0.85 (0.56â1.29) in fish eaters and 0.55 (0.39â0.78) in vegetarians, P for heterogeneity=0.002. The RRs for all malignant neoplasms were 0.82 (0.73â0.93) in fish eaters and 0.88 (0.81â0.96) in vegetarians (P for heterogeneity=0.001).
Conclusion:
The incidence of some cancers may be lower in fish eaters and vegetarians than in meat eaters
Overview of the Nordic Seas CARINA data and salinity measurements
Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic). The data have been subject to rigorous quality control (QC) in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS), the Atlantic (ATL) and the Southern Ocean (SO). With the adjustments the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004) and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. The Arctic Mediterranean Seas include the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. This contribution provides an overview of the CARINA data from the Nordic Seas and summarises the findings of the QC of the salinity data. One cruise had salinity data that were of questionable quality, and these have been removed from the data product. An evaluation of the consistency of the quality controlled salinity data suggests that they are consistent to at least ±0.005
Novel Ferromagnetic Atom Waveguide with in situ loading
Magneto-optic and magnetostatic trapping is realized near a surface using
current carrying coils wrapped around magnetizable cores. A cloud of 10^7
Cesium atoms is created with currents less than 50 mA. Ramping up the current
while maintaining optical dissipation leads to tightly confined atom clouds
with an aspect ratio of 1:1000. We study the 3D character of the magnetic
potential and characterize atom number and density as a function of the applied
current. The field gradient in the transverse dimension has been varied from <
10 G/cm to > 1 kG/cm. By loading and cooling atoms in-situ, we have eliminated
the problem of coupling from a MOT into a smaller phase space.Comment: 4 pages, 4 figure
Biometric variables predict stone tool functional performance more effectively than toolâform attributes: a case study in handaxe loading capabilities
Both the form of a stone tool and the anatomy of the individual using it have potential to influence its cutting performance. To date, however, the selective pressures acting on stoneâtool form and hominin biometric/biomechanical attributes have been investigated in isolation and their relative influence on performance have never been compared directly. This paper examines the influence of both toolâform attributes and biometric variation on the functional performance of Acheulean handaxes. Specifically, it investigates the impact of 13 tool attributes and eight biometric traits on the working forces applied through the edge of 457 replica tools. The relative contribution of toolâform and biometric attributes to handaxe loading levels were examined statistically. Results identify that both toolâform attributes and biometric traits are significantly related to loading; however, toolâuser biometric variation has a substantially greater impact relative to toolâform attributes. This difference was demonstrated by up to a factor of 10. These results bear directly on the coâevolutionary relationships of stone tools and hominin anatomy, and the comparative strength of selective pressure acting on each. They also underline why handaxe forms may have been free to vary in form across time and space without necessarily incurring critical impacts on their functional capabilities
Propagation of Bose-Einstein condensates in a magnetic waveguide
Gaseous Bose-Einstein condensates of 2-3 million atoms were loaded into a
microfabricated magnetic trap using optical tweezers. Subsequently, the
condensates were released into a magnetic waveguide and propagated 12 mm.
Single-mode propagation was observed along homogeneous segments of the
waveguide. Inhomogeneities in the guiding potential arose from geometric
deformations of the microfabricated wires and caused strong transverse
excitations. Such deformations may restrict the waveguide physics that can be
explored with propagating condensates.Comment: 5 pages, 4 figure
Heat treatment significantly increases the sharpness of silcrete stone tools
Humans were regularly heat-treating stone tool raw materials as early as 130,000 years ago. The late Middle Stone Age (MSA) and Late Stone Age (LSA) of South Africa's Western Cape region provides some of the earliest and most pervasive archaeological evidence for this behaviour. While archaeologists are beginning to understand the flaking implications of raw material heat treatment, its potential functional benefits remain unanswered. Using silcrete from the Western Cape region, we investigate the impact of heat treatment on stone tool cutting performance. We quantify the sharpness of silcrete in its natural, unheated form, before comparing it with silcrete heated in three different conditions. Results show that heat-treated silcrete can be significantly sharper than unheated alternatives, with cutting forces halving and energy requirements reducing by approximately two-thirds. The data suggest that silcrete may have been heat treated during the South African MSA and LSA to increase the sharpness and performance of stone cutting edges. This early example of material engineering has implications for understanding Stone Age populationsâ technological capabilities, inventiveness and raw material choices. We predict that heat-treatment behaviours in other prehistoric and ethnographic contexts may also be linked to increases in edge sharpness and concerns about functional performance
Characterizing the Gravitational Wave Signature from Cosmic String Cusps
Cosmic strings are predicted to form kinks and cusps that travel along the
string at close to the speed of light. These disturbances are radiated away as
highly beamed gravitational waves that produce a burst like pulse as the cone
of emission sweeps past an observer. Gravitational wave detectors such as the
Laser Interferometer Space Antenna (LISA) and the Laser Interferometer
Gravitational wave Observatory (LIGO) will be capable of detecting these bursts
for a wide class of string models. Such a detection would illuminate the fields
of string theory, cosmology, and relativity. Here we develop template based
Markov Chain Monte Carlo (MCMC) techniques that can efficiently detect and
characterize the signals from cosmic string cusps. We estimate how well the
signal parameters can be recovered by the advanced LIGO-Virgo network and the
LISA detector using a combination of MCMC and Fisher matrix techniques. We also
consider joint detections by the ground and space based instruments. We show
that a parallel tempered MCMC approach can detect and characterize the signals
from cosmic string cusps, and we demonstrate the utility of this approach on
simulated data from the third round of Mock LISA Data Challenges (MLDCs).Comment: 10 pages, 10 figure
Bose-Einstein Condensation in a Surface Micro Trap
Bose-Einstein condensation has been achieved in a magnetic surface micro trap
with 4x10^5 87Rb atoms. The strongly anisotropic trapping potential is
generated by a microstructure which consists of microfabricated linear copper
conductors at a width ranging from 3 to 30 micrometer. After loading a high
number of atoms from a pulsed thermal source directly into a magneto-optical
trap (MOT) the magnetically stored atoms are transferred into the micro trap by
adiabatic transformation of the trapping potential. The complete in vacuo trap
design is compatible with ultrahigh vacuum below 2x10^(-11) mbar.Comment: 4 pages, 4 figure
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