1,476 research outputs found
Coseismic horizontal slip revealed by sheared clastic dikes in the Dead Sea Basin
Peer reviewedPostprin
Cancer metabolism at a glance
A defining hallmark of cancer is uncontrolled cell proliferation. This is initiated once cells have accumulated alterations in signaling pathways that control metabolism and proliferation, wherein the metabolic alterations provide the energetic and anabolic demands of enhanced cell proliferation. How these metabolic requirements are satisfied depends, in part, on the tumor microenvironment, which determines the availability of nutrients and oxygen. In this Cell Science at a Glance paper and the accompanying poster, we summarize our current understanding of cancer metabolism, emphasizing pathways of nutrient utilization and metabolism that either appear or have been proven essential for cancer cells. We also review how this knowledge has contributed to the development of anticancer therapies that target cancer metabolism
Adherence to Nutrition and Physical Activity Cancer Prevention Guidelines and Development of Colorectal Adenoma.
Adherence to the American Cancer Society's (ACS) Nutrition and Physical Activity Cancer Prevention Guidelines is associated with reductions in overall cancer incidence and mortality, including site-specific cancers such as colorectal cancer. We examined the relationship between baseline adherence to the ACS guidelines and (1) baseline adenoma characteristics and (2) odds of recurrent colorectal adenomas over 3 years of follow-up. Cross-sectional and prospective analyses with a pooled sample of participants from the Wheat Bran Fiber (n = 503) and Ursodeoxycholic Acid (n = 854) trials were performed. A cumulative adherence score was constructed using baseline self-reported data regarding body size, diet, physical activity and alcohol consumption. Multivariable logistic regression demonstrated significantly reduced odds of having three or more adenomas at baseline for moderately adherent (odds ratio [OR] = 0.67, 95% confidence intervals [CI]: 0.46⁻0.99) and highly adherent (OR = 0.50, 95% CI: 0.31⁻0.81) participants compared to low adherers (p-trend = 0.005). Conversely, guideline adherence was not associated with development of recurrent colorectal adenoma (moderate adherence OR = 1.16, 95% CI: 0.85⁻1.59, high adherence OR = 1.23, 95% CI: 0.85⁻1.79)
A genomic map of the effects of linked selection in Drosophila
Natural selection at one site shapes patterns of genetic variation at linked
sites. Quantifying the effects of 'linked selection' on levels of genetic
diversity is key to making reliable inference about demography, building a null
model in scans for targets of adaptation, and learning about the dynamics of
natural selection. Here, we introduce the first method that jointly infers
parameters of distinct modes of linked selection, notably background selection
and selective sweeps, from genome-wide diversity data, functional annotations
and genetic maps. The central idea is to calculate the probability that a
neutral site is polymorphic given local annotations, substitution patterns, and
recombination rates. Information is then combined across sites and samples
using composite likelihood in order to estimate genome-wide parameters of
distinct modes of selection. In addition to parameter estimation, this approach
yields a map of the expected neutral diversity levels along the genome. To
illustrate the utility of our approach, we apply it to genome-wide resequencing
data from 125 lines in Drosophila melanogaster and reliably predict diversity
levels at the 1Mb scale. Our results corroborate estimates of a high fraction
of beneficial substitutions in proteins and untranslated regions (UTR). They
allow us to distinguish between the contribution of sweeps and other modes of
selection around amino acid substitutions and to uncover evidence for pervasive
sweeps in untranslated regions (UTRs). Our inference further suggests a
substantial effect of linked selection from non-classic sweeps. More generally,
we demonstrate that linked selection has had a larger effect in reducing
diversity levels and increasing their variance in D. melanogaster than
previously appreciated
BCC vs. HCP - The Effect of Crystal Symmetry on the High Temperature Mobility of Solid He
We report results of torsional oscillator (TO) experiments on solid He at
temperatures above 1K. We have previously found that single crystals, once
disordered, show some mobility (decoupled mass) even at these rather high
temperatures. The decoupled mass fraction with single crystals is typically 20-
30%. In the present work we performed similar measurements on polycrystalline
solid samples. The decoupled mass with polycrystals is much smaller, 1%,
similar to what is observed by other groups. In particular, we compared the
properties of samples grown with the TO's rotation axis at different
orientations with respect to gravity. We found that the decoupled mass fraction
of bcc samples is independent of the angle between the rotation axis and
gravity. In contrast, hcp samples showed a significant difference in the
fraction of decoupled mass as the angle between the rotation axis and gravity
was varied between zero and 85 degrees. Dislocation dynamics in the solid
offers one possible explanation of this anisotropy.Comment: 10 pages, 5 figures, to appear in Journal of Low Temperature Physics
- special issue on Supersolidit
A Possible Hidden Population of Spherical Planetary Nebulae
We argue that relative to non-spherical planetary nebulae (PNs), spherical
PNs are about an order of magnitude less likely to be detected, at distances of
several kiloparsecs. Noting the structure similarity of halos around
non-spherical PNs to that of observed spherical PNs, we assume that most
unobserved spherical PNs are also similar in structure to the spherical halos
around non-spherical PNs. The fraction of non-spherical PNs with detected
spherical halos around them, taken from a recent study, leads us to the claim
of a large (relative to that of non-spherical PNs) hidden population of
spherical PNs in the visible band. Building a toy model for the luminosity
evolution of PNs, we show that the claimed detection fraction of spherical PNs
based on halos around non-spherical PNs, is compatible with observational
sensitivities. We use this result to update earlier studies on the different PN
shaping routes in the binary model. We estimate that ~30% of all PNs are
spherical, namely, their progenitors did not interact with any binary
companion. This fraction is to be compared with the ~3% fraction of observed
spherical PNs among all observed PNs. From all PNs, ~15% owe their moderate
elliptical shape to the interaction of their progenitors with planets, while
\~55% of all PNs owe their elliptical or bipolar shapes to the interaction of
their progenitors with stellar companions.Comment: AJ, in pres
Phenomenological Constraints on Extended Quark Sectors
We study the flavor physics in two extensions of the quark sector of the
Standard Model (SM): a four generation model and a model with a single
vector--like down--type quark (VDQ). In our analysis we take into account the
experimental constraints from tree--level charged current processes, rare Kaon
decay processes, rare B decay processes, the decay, ,
and mass differences, and the CP violating parameters \frac
\epsilon^\prime}{\epsilon}, and . All the constraints
are taken at two sigma. We find bounds on parameters which can be used to
represent the New Physics contributions in these models (, and in the
four--generation model, and , and in the VDQ model)
due to all the above constraints. In both models the predicted ranges for
(the CP asymmetry in semi-leptonic decays), ,
, and can be significantly higher than the predictions of the
SM, while the allowed ranges for and for are
consistent with the SM prediction.Comment: 22 pages, 5 figures (v3: added a reference, updated a reference,
added missing units
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