3,082 research outputs found
Affective state influences retrieval-induced forgetting for integrated knowledge
Selectively testing parts of learned materials can impair later memory for nontested materials. Research has shown that such retrieval-induced forgetting occurs for low-integrated materials but may be prevented for high-integrated materials. However, previous research has neglected one factor that is ubiquitous in real-life testing: affective stat
Local Delivery of Human Tissue Kallikrein Gene Accelerates Spontaneous Angiogenesis in Mouse Model of Hindlimb Ischemia
Background —Human tissue kallikrein (HK) releases kinins from kininogen. We investigated whether adenovirus-mediated HK gene delivery is angiogenic in the context of ischemia. Methods and Results —Hindlimb ischemia, caused by femoral artery excision, increased muscular capillary density ( P 1 receptor gene ( P 1 receptors blunted ischemia-induced angiogenesis ( P 2 receptor antagonism was ineffective. Intramuscular delivery of adenovirus containing the HK gene (Ad.CMV-cHK) enhanced the increase in capillary density caused by ischemia (969±32 versus 541±18 capillaries/mm 2 for control, P P P 1 or B 2 receptors prevented HK-induced angiogenesis. Conclusions —HK gene delivery enhances the native angiogenic response to ischemia. Angiogenesis gene therapy with HK might be applicable to peripheral occlusive vascular disease
Evidence for variation in the effective population size of animal mitochondrial DNA
Background: It has recently been shown that levels of diversity in mitochondrial DNA are remarkably constant across animals of diverse census population sizes and ecologies, which has led to the suggestion that the effective population of mitochondrial DNA may be relatively constant. Results: Here we present several lines of evidence that suggest, to the contrary, that the effective population size of mtDNA does vary, and that the variation can be substantial. First, we show that levels of mitochondrial and nuclear diversity are correlated within all groups of animals we surveyed. Second, we show that the effectiveness of selection on non-synonymous mutations, as measured by the ratio of the numbers of non-synonymous and synonymous polymorphisms, is negatively correlated to levels of mitochondrial diversity. Finally, we estimate the effective population size of mitochondrial DNA in selected mammalian groups and show that it varies by at least an order of magnitude. Conclusions: We conclude that there is variation in the effective population size of mitochondria. Furthermore we suggest that the relative constancy of DNA diversity may be due to a negative correlation between the effective population size and the mutation rate per generation
Congenital lobar emphysema: a case report
Congenital lobar emphysema is a rare variety of congenital malformation of lung characterized by over distension of a lobe of a lung due to partial obstruction of the bronchus. We are reporting a neonate admitted in the pediatric emergency ward with the respiratory distress since 16th day of life
Time Reversal Violation from the entangled B0-antiB0 system
We discuss the concepts and methodology to implement an experiment probing
directly Time Reversal (T) non-invariance, without any experimental connection
to CP violation, by the exchange of "in" and "out" states. The idea relies on
the B0-antiB0 entanglement and decay time information available at B factories.
The flavor or CP tag of the state of the still living neutral meson by the
first decay of its orthogonal partner overcomes the problem of irreversibility
for unstable systems, which prevents direct tests of T with incoherent particle
states. T violation in the time evolution between the two decays means
experimentally a difference between the intensities for the time-ordered (l^+
X, J/psi K_S) and (J/psi K_L, l^- X) decays, and three other independent
asymmetries. The proposed strategy has been applied to simulated data samples
of similar size and features to those currently available, from which we
estimate the significance of the expected discovery to reach many standard
deviations.Comment: 17 pages, 2 figures, 6 table
The role of mentorship in protege performance
The role of mentorship on protege performance is a matter of importance to
academic, business, and governmental organizations. While the benefits of
mentorship for proteges, mentors and their organizations are apparent, the
extent to which proteges mimic their mentors' career choices and acquire their
mentorship skills is unclear. Here, we investigate one aspect of mentor
emulation by studying mentorship fecundity---the number of proteges a mentor
trains---with data from the Mathematics Genealogy Project, which tracks the
mentorship record of thousands of mathematicians over several centuries. We
demonstrate that fecundity among academic mathematicians is correlated with
other measures of academic success. We also find that the average fecundity of
mentors remains stable over 60 years of recorded mentorship. We further uncover
three significant correlations in mentorship fecundity. First, mentors with
small mentorship fecundity train proteges that go on to have a 37% larger than
expected mentorship fecundity. Second, in the first third of their career,
mentors with large fecundity train proteges that go on to have a 29% larger
than expected fecundity. Finally, in the last third of their career, mentors
with large fecundity train proteges that go on to have a 31% smaller than
expected fecundity.Comment: 23 pages double-spaced, 4 figure
Robust estimation of microbial diversity in theory and in practice
Quantifying diversity is of central importance for the study of structure,
function and evolution of microbial communities. The estimation of microbial
diversity has received renewed attention with the advent of large-scale
metagenomic studies. Here, we consider what the diversity observed in a sample
tells us about the diversity of the community being sampled. First, we argue
that one cannot reliably estimate the absolute and relative number of microbial
species present in a community without making unsupported assumptions about
species abundance distributions. The reason for this is that sample data do not
contain information about the number of rare species in the tail of species
abundance distributions. We illustrate the difficulty in comparing species
richness estimates by applying Chao's estimator of species richness to a set of
in silico communities: they are ranked incorrectly in the presence of large
numbers of rare species. Next, we extend our analysis to a general family of
diversity metrics ("Hill diversities"), and construct lower and upper estimates
of diversity values consistent with the sample data. The theory generalizes
Chao's estimator, which we retrieve as the lower estimate of species richness.
We show that Shannon and Simpson diversity can be robustly estimated for the in
silico communities. We analyze nine metagenomic data sets from a wide range of
environments, and show that our findings are relevant for empirically-sampled
communities. Hence, we recommend the use of Shannon and Simpson diversity
rather than species richness in efforts to quantify and compare microbial
diversity.Comment: To be published in The ISME Journal. Main text: 16 pages, 5 figures.
Supplement: 16 pages, 4 figure
The Impact of the Oncotype DX Breast Cancer Assay on Treatment Decisions for Women With Estrogen Receptor-Positive, Node-Negative Breast Carcinoma in Hong Kong
Background
The Oncotype DX Breast Cancer Assay is validated to assess risk of distant recurrence and likelihood of chemotherapy (CT) benefit in estrogen receptor-positive ESBC in various populations. In Hong Kong, > 80% of breast cancers are early stage breast cancer (ESBC) and > 60% of these women receive CT. This prospective study measured changes in CT type and recommendations, as well as physician impression of assay impact in a homogenous Chinese population.
Methods
Consecutive patients with estrogen receptor-positive, T1-3 N0-1mi M0 ESBC were offered enrollment. After surgery, physicians discussed treatment options with patients, then ordered the assay, then reassessed treatment recommendation considering assay results. Changes in treatment recommendation, CT utilization, physician confidence, and physician rating of influence on their treatment recommendations were measured.
Results
A total of 146 evaluable patients received pre- and post-testing treatment recommendations. CT recommendations (including changes in intensity of CT) were changed for 34 of 146 patients (23.3%; 95% confidence interval, 16.7%-31.0%); change in intensity occurred in 7 of 146 (4.8%). There were 27 changes in treatment recommendations of adding or removing CT altogether (18.5% change; 95% confidence interval, 12.6%-25.8%). CT recommendations decreased from 52.1% to 37.7%, a net absolute reduction of 14.4% (P < .001; 27.6% net relative reduction). Pre-assay, 96% of physicians agreed/strongly agreed that they were confident in their treatment recommendation; post-assay, 90% of physicians agreed/strongly agreed with the same statement. Thirty percent of physicians agreed/strongly agreed that the test had influenced their recommendation, similar to the proportion of changed recommendations.
Conclusions
The Oncotype DX Assay appears to influence physician ESBC adjuvant treatment recommendations in Hong Kong.published_or_final_versio
Phenomenological Consequences of sub-leading Terms in See-Saw Formulas
Several aspects of next-to-leading (NLO) order corrections to see-saw
formulas are discussed and phenomenologically relevant situations are
identified. We generalize the formalism to calculate the NLO terms developed
for the type I see-saw to variants like the inverse, double or linear see-saw,
i.e., to cases in which more than two mass scales are present. In the standard
type I case with very heavy fermion singlets the sub-leading terms are
negligible. However, effects in the percent regime are possible when
sub-matrices of the complete neutral fermion mass matrix obey a moderate
hierarchy, e.g. weak scale and TeV scale. Examples are cancellations of large
terms leading to small neutrino masses, or inverse see-saw scenarios. We
furthermore identify situations in which no NLO corrections to certain
observables arise, namely for mu-tau symmetry and cases with a vanishing
neutrino mass. Finally, we emphasize that the unavoidable unitarity violation
in see-saw scenarios with extra fermions can be calculated with the formalism
in a straightforward manner.Comment: 22 pages, matches published versio
Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays
The angular distributions of the baryon-antibaryon low-mass enhancements seen
in the charmless three-body baryonic B decays B+ -> p pbar K+, B0 -> p pbar Ks,
and B0 -> p Lambdabar pi- are reported. A quark fragmentation interpretation is
supported, while the gluonic resonance picture is disfavored. Searches for the
Theta+ and Theta++ pentaquarks in the relevant decay modes and possible
glueball states G with 2.2 GeV/c2 < M-ppbar < 2.4 GeV/c2 in the ppbar systems
give null results. We set upper limits on the products of branching fractions,
B(B0 -> Theta+ p)\times B(Theta+ -> p Ks) Theta++
pbar) \times B(Theta++ -> p K+) G K+) \times
B(G -> p pbar) < 4.1 \times 10^{-7} at the 90% confidence level. The analysis
is based on a 140 fb^{-1} data sample recorded on the Upsilon(4S) resonance
with the Belle detector at the KEKB asymmetric-energy e+e- collider.Comment: 14 pages, 13 figure files, update of hep-ex/0409010 for journal
submisssio
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