16,657 research outputs found
Researchers’ opinions about ethically sound dissemination of BCI research to the public media
BCI research and (future) applications raise ethical questions. A websurvey among 144 BCI researchers identified disseminating BCI research to the public media as a central topic. Most researchers felt that BCI scientists must responsibly communicate with the media and that general ethical guidelines on BCI research and application are needed within the next 5 years. We recommend further debate on ethical aspects related to BCI and the development of guidelines
Prestige drives epistemic inequality in the diffusion of scientific ideas
The spread of ideas in the scientific community is often viewed as a
competition, in which good ideas spread further because of greater intrinsic
fitness, and publication venue and citation counts correlate with importance
and impact. However, relatively little is known about how structural factors
influence the spread of ideas, and specifically how where an idea originates
might influence how it spreads. Here, we investigate the role of faculty hiring
networks, which embody the set of researcher transitions from doctoral to
faculty institutions, in shaping the spread of ideas in computer science, and
the importance of where in the network an idea originates. We consider
comprehensive data on the hiring events of 5032 faculty at all 205
Ph.D.-granting departments of computer science in the U.S. and Canada, and on
the timing and titles of 200,476 associated publications. Analyzing five
popular research topics, we show empirically that faculty hiring can and does
facilitate the spread of ideas in science. Having established such a mechanism,
we then analyze its potential consequences using epidemic models to simulate
the generic spread of research ideas and quantify the impact of where an idea
originates on its longterm diffusion across the network. We find that research
from prestigious institutions spreads more quickly and completely than work of
similar quality originating from less prestigious institutions. Our analyses
establish the theoretical trade-offs between university prestige and the
quality of ideas necessary for efficient circulation. Our results establish
faculty hiring as an underlying mechanism that drives the persistent epistemic
advantage observed for elite institutions, and provide a theoretical lower
bound for the impact of structural inequality in shaping the spread of ideas in
science.Comment: 10 pages, 8 figures, 1 tabl
Thin n-i-p radiation-resistant solar cell feasibility study
Silicon solar cells were fabricated to verify the predictions that: (1) thin n(+)pp(+) cells can provide high values of open circuit voltage even when high resistivity base material ( 1000 omega-cm) is used; (2) cells with good p(+) back contacts will display an increase in open circuit voltage with decreasing cell thickness; and (3) high quality, thin, high resistivity, solar cells can be made using processing compatible with conventional practice. Analysis of I-V and spectral response measurements of these cells confirmed theoretical predictions and thereby pointed to voltages beyond the near 600 mV obtained in this study
Mutual information for examining correlations in DNA
This paper examines two methods for finding whether long-range correlations
exist in DNA: a fractal measure and a mutual information technique. We evaluate
the performance and implications of these methods in detail. In particular we
explore their use comparing DNA sequences from a variety of sources. Using
software for performing in silico mutations, we also consider evolutionary
events leading to long range correlations and analyse these correlations using
the techniques presented. Comparisons are made between these virtual sequences,
randomly generated sequences, and real sequences. We also explore correlations
in chromosomes from different species.Comment: 8 pages, 3 figure
Recent progress in high-output-voltage silicon solar cells
The status of the technology associated with the development of high output voltage silicon solar cells is reported. The energy conversion efficiency of a double diffusion process is compared to that of a single diffusion process. The efficiency of a 0.1 ohm/cm solar cell is characterized both before and after covering
Identification of LDH-A as a therapeutic target for cancer cell killing via (i) p53/NAD(H)-dependent and (ii) p53 independent pathways
Most cancer cells use aerobic glycolysis to fuel their growth. The enzyme lactate dehydrogenase-A (LDH-A) is key to cancer’s glycolytic phenotype, catalysing the regeneration of nicotinamide adenine dinucleotide (NAD þ ) from reduced nicotinamide adenine dinucleotide (NADH) necessary to sustain glycolysis. As such, LDH-A is a promising target for anticancer therapy. Here we ask if the tumour suppressor p53, a major regulator of cellular metabolism, influences the response of cancer cells to LDH-A suppression. LDH-A knockdown by RNA interference (RNAi) induced cancer cell death in p53 wild-type, mutant and p53-null human cancer cell lines, indicating that endogenous LDH-A promotes cancer cell survival irrespective of cancer cell p53 status. Unexpectedly,however,weuncoveredanovelroleforp53intheregulationofcancercellNADþ anditsreducedformNADH.Thus, LDH-A silencing by RNAi, or its inhibition using a small-molecule inhibitor, resulted in a p53-dependent increase in the cancer cell ratioofNADH:NADþ.Thiseffectwasspecificforp53þ/þ cancercellsandcorrelatedwith(i)reducedactivityofNADþ-dependent deacetylase sirtuin 1 (SIRT1) and (ii) an increase in acetylated p53, a known target of SIRT1 deacetylation activity. In addition, activation of the redox-sensitive anticancer drug EO9 was enhanced selectively in p53 þ / þ cancer cells, attributable to increased activity of NAD(P)H-dependent oxidoreductase NQO1 (NAD(P)H quinone oxidoreductase 1). Suppressing LDH-A increased EO9-inducedDNAdamageinp53þ/þ cancercells,butimportantlyhadnoadditiveeffectinnon-cancercells.Ourresultsidentifya unique strategy by which the NADH/NADþ cellular redox status can be modulated in a cancer-specific, p53-dependent manner and we show that this can impact upon the activity of important NAD(H)-dependent enzymes. To summarise, this work indicates two distinct mechanisms by which suppressing LDH-A could potentially be used to kill cancer cells selectively, (i) through induction of apoptosis, irrespective of cancer cell p53 status and (ii) as a part of a combinatorial approach with redox-sensitive anticancer drugs via a novel p53/NAD(H)-dependent mechanism
Air-sea interaction in the tropical Pacific Ocean
Charts of 3-month sea surface temperature (SST) anomalies in the eastern tropical Pacific Ocean were produced for the period 1949 to 1970. The anomalies along the United States and South American west coasts and in the eastern tropical Pacific appeared to be oscillating in phase during this period. Similarly, the satellite-derived cloudiness for each of four quadrants of the Pacific Ocean (130 deg E to 100 deg W, 30 deg N to 25 deg S) appeared to be oscillating in phase. In addition, a global tropical cloudiness oscillation from 30 deg N to 30 deg S was noted from 1965 to 1970, by using monthly satellite television nephanalyses. The SST anomalies were found to have a good degree of correlation both positive and negative with the following monthly geophysical parameters: (1) satellite-derived cloudiness, (2) strength of the North and South Pacific semipermanent anticyclones, (3) tropical Pacific island rainfall, and (4) Darwin surface pressure. Several strong direct local and crossequatorial relationships were noted. In particular, the high degree of correlation between the tropical island rainfall and the SST anomalies (r = +0.93) permitted the derivation of SST's for the tropical Pacific back to 1905. The close occurrence of cold tropical SST and North Pacific 700-mb positive height anomalies with central United States drought conditions was noted
Loss of Individual MicroRNAs Causes Mutant Phenotypes in Sensitized Genetic Backgrounds in \u3cem\u3eC. elegans\u3c/em\u3e
MicroRNAs (miRNAs) are small, noncoding RNAs that regulate the translation and/or stability of their mRNA targets. Previous work showed that for most miRNA genes of C. elegans, single-gene knockouts did not result in detectable mutant phenotypes. This may be due, in part, to functional redundancy between miRNAs. However, in most cases, worms carrying deletions of all members of a miRNA family do not display strong mutant phenotypes. They may function together with unrelated miRNAs or with non-miRNA genes in regulatory networks, possibly to ensure the robustness of developmental mechanisms. To test this, we examined worms lacking individual miRNAs in genetically sensitized backgrounds. These include genetic backgrounds with reduced processing and activity of all miRNAs or with reduced activity of a wide array of regulatory pathways. With these two approaches, we identified mutant phenotypes for 25 out of 31 miRNAs included in this analysis. Our findings describe biological roles for individual miRNAs and suggest that the use of sensitized genetic backgrounds provides an efficient approach for miRNA functional analysis
Radiative association and inverse predissociation of oxygen atoms
The formation of \mbox{O}_2 by radiative association and by inverse
predissociation of ground state oxygen atoms is studied using
quantum-mechanical methods. Cross sections, emission spectra, and rate
coefficients are presented and compared with prior experimental and theoretical
results. At temperatures below 1000~K radiative association occurs by approach
along the state of \mbox{O}_2 and above 1000~K inverse
predissociation through the \mbox{B}\,{}^3\Sigma_u^- state is the dominant
mechanism. This conclusion is supported by a quantitative comparison between
the calculations and data obtained from hot oxygen plasma spectroscopy.Comment: submitted to Phys. Rev. A (Sept. 7., 1994), 19 pages, 4 figures,
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Relationship between adiposity and admixture in African-American and Hispanic-American women.
ObjectiveThe objective of this study was to investigate whether differences in admixture in African-American (AFA) and Hispanic-American (HA) adult women are associated with adiposity and adipose distribution.DesignThe proportion of European, sub-Saharan African and Amerindian admixture was estimated for AFA and HA women in the Women's Heath Initiative using 92 ancestry informative markers. Analyses assessed the relationship between admixture and adiposity indices.SubjectsThe subjects included 11 712 AFA and 5088 HA self-identified post-menopausal women.ResultsThere was a significant positive association between body mass index (BMI) and African admixture when BMI was considered as a continuous variable, and age, education, physical activity, parity, family income and smoking were included covariates (P<10(-4)). A dichotomous model (upper and lower BMI quartiles) showed that African admixture was associated with a high odds ratio (OR=3.27 (for 100% admixture compared with 0% admixture), 95% confidence interval 2.08-5.15). For HA, there was no association between BMI and admixture. In contrast, when waist-to-hip ratio (WHR) was used as a measure of adipose distribution, there was no significant association between WHR and admixture in AFA but there was a strong association in HA (P<10(-4); OR Amerindian admixture=5.93, confidence interval=3.52-9.97).ConclusionThese studies show that: (1) African admixture is associated with BMI in AFA women; (2) Amerindian admixture is associated with WHR but not BMI in HA women; and (3) it may be important to consider different measurements of adiposity and adipose distribution in different ethnic population groups
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