5,270 research outputs found
El o los fines de la etnografía: del desorden de lo experimental al desorden de lo barroco
Desde los pasados años ochenta, con la crítica a la representación etnográfica de Writing Culture, la escritura de textos etnográficos en antropología se ha distinguido por la aparición perenne de neófitos de nuevos trabajos compuestos de tropos y estrategias estilísticas que reflejan las diversas influencias de un periodo de crítica. Estos textos “desordenados” eran, y son, valorados como experimentos. Este ensayo argumenta como crítica, que estas etnografías actuales no son tanto experimentales como barrocas, indicando quizá un límite a la forma etnográfica histórica y la necesidad de empujar de nuevo el espíritu de lo experimental hacia las condiciones de producir etnografía en el trabajo de campo. Esta “refuncionalización” de la etnografía en su espíritu experimental reconocería y abordaría el límite presente de lo barroco, al que este periodo de crítica nos ha conducido de los últimos años ochenta en adelante.Since the 1980s, and the Writing Culture critique of ethnographic representation, the writing of ethnographic texts in anthropology has been distinguished by the perennial appearance by neophytes of new works composed of tropes and stylistic strategies that reflect the diverse influences of the period of critique. These “messy” texts were, and are, valorizied as experiments. This essay argues as critique that current such ethnographies are not so much experimental as baroque. Indicating perhaps a limit of the historic ethnographic form, and the need to push the spirit of experiment back toward the conditions of producing ethnography in fieldwork. This “refunctioning” of ethnography in its experimental spirit would recognize and address the present limit of the baroque to which the 1980s period of critique and after has led
Using molecular genetic information to infer causality in observational data:Mendelian randomisation
The Flight Spectral Response of the ACIS Instrument
We discuss the flight calibration of the spectral response of the Advanced
CCD Imaging Spectrometer (ACIS) on-board the Chandra X-ray Observatory (CXO).
The spectral resolution and sensitivity of the ACIS instrument have both been
evolving over the course of the mission. The spectral resolution of the
frontside-illuminated (FI) CCDs changed dramatically in the first month of the
mission due to radiation damage. Since that time, the spectral resolution of
the FI CCDs and the backside-illuminated (BI) CCDs have evolved gradually with
time. We demonstrate the efficacy of charge-transfer inefficiency (CTI)
correction algorithms which recover some of the lost performance. The detection
efficiency of the ACIS instrument has been declining throughout the mission,
presumably due to a layer of contamination building up on the filter and/or
CCDs. We present a characterization of the energy dependence of the excess
absorption and demonstrate software which models the time dependence of the
absorption from energies of 0.4 keV and up. The spectral redistribution
function and the detection efficiency are well-characterized at energies from
1.5 to 8.0 keV. The calibration at energies below 1.5 keV is challenging
because of the lack of strong lines in the calibration source and also because
of the inherent non-linear dependence with energy of the CTI and the absorption
by the contamination layer. We have been using data from celestial sources with
relatively simple spectra to determine the quality of the calibration below 1.5
keV. The analysis of these observations demonstrate that the CTI correction
recovers a significant fraction of the spectral resolution of the FI CCDs and
the models of the time-dependent absorption result in consistent measurements
of the flux at low energies for data from a BI (S3) CCD.Comment: 12 pages, 15 figures, SPIE style file, To appear in "Astronomical
Telescopes and Instrumentation 2002" (SPIE Conference Proceedings), eds. J.E.
Truemper and H.D. Tananbau
Investigating causality in the association between 25(OH)D and schizophrenia
Vitamin D deficiency is associated with increased risk of schizophrenia. However, it is not known whether this association is causal or what the direction of causality is. We performed two sample bidirectional Mendelian randomization analysis using single nucleotide polymorphisms (SNPs) robustly associated with serum 25(OH)D to investigate the causal effect of 25(OH)D on risk of schizophrenia, and SNPs robustly associated with schizophrenia to investigate the causal effect of schizophrenia on 25(OH)D. We used summary data from genome-wide association studies and meta-analyses of schizophrenia and 25(OH)D to obtain betas and standard errors for the SNP-exposure and SNP-outcome associations. These were combined using inverse variance weighted fixed effects meta-analyses. In 34,241 schizophrenia cases and 45,604 controls, there was no clear evidence for a causal effect of 25(OH)D on schizophrenia risk. The odds ratio for schizophrenia per 10% increase in 25(OH)D conferred by the four 25(OH)D increasing SNPs was 0.992 (95% CI: 0.969 to 1.015). In up to 16,125 individuals with measured serum 25(OH)D, there was no clear evidence that genetic risk for schizophrenia causally lowers serum 25(OH)D. These findings suggest that associations between schizophrenia and serum 25(OH)D may not be causal. Therefore, vitamin D supplementation may not prevent schizophrenia.</p
Associations between smoking and caffeine consumption in two European cohorts
AIMS: To estimate associations between smoking initiation, smoking persistence and smoking heaviness and caffeine consumption in two population‐based samples from the Netherlands and the United Kingdom. DESIGN: Observational study employing data on self‐reported smoking behaviour and caffeine consumption. SETTING: Adults from the general population in the Netherlands and the United Kingdom. PARTICIPANTS: Participants from the Netherlands Twin Register [NTR: n = 21 939, mean age 40.8, standard deviation (SD) = 16.9, 62.6% female] and the Avon Longitudinal Study of Parents and Children (ALSPAC: n = 9086, mean age 33.2, SD = 4.7, 100% female). MEASUREMENTS: Smoking initiation (ever versus never smoking), smoking persistence (current versus former smoking), smoking heaviness (number of cigarettes smoked) and caffeine consumption in mg per day through coffee, tea, cola and energy drinks. FINDINGS: After correction for age, gender (NTR), education and social class (ALSPAC), smoking initiation was associated with consuming on average 52.8 [95% confidence interval (CI) = 45.6–60.0; NTR] and 59.5 (95% CI = 51.8–67.2; ALSPAC) mg more caffeine per day. Smoking persistence was also associated with consuming more caffeine [+57.9 (95% CI = 45.2–70.5) and +83.2 (95% CI = 70.2–96.3) mg, respectively]. Each additional cigarette smoked per day was associated with 3.7 (95% CI = 1.9–5.5; NTR) and 8.4 (95% CI = 6.9–10.0; ALSPAC) mg higher daily caffeine consumption in current smokers. Smoking was associated positively with coffee consumption and less strongly with cola and energy drinks. For tea, associations were positive in ALSPAC and negative in NTR. CONCLUSIONS: There appears to be a positive association between smoking and caffeine consumption in the Netherlands and the United Kingdom
Hot Carrier Transport and Photocurrent Response in Graphene
Strong electron-electron interactions in graphene are expected to result in
multiple-excitation generation by the absorption of a single photon. We show
that the impact of carrier multiplication on photocurrent response is enhanced
by very inefficient electron cooling, resulting in an abundance of hot
carriers. The hot-carrier-mediated energy transport dominates the photoresponse
and manifests itself in quantum efficiencies that can exceed unity, as well as
in a characteristic dependence of the photocurrent on gate voltages. The
pattern of multiple photocurrent sign changes as a function of gate voltage
provides a fingerprint of hot-carrier-dominated transport and carrier
multiplication.Comment: 4 pgs, 2 fg
Civilian casualties and public support for military action: Experimental evidence
In contrast to the expansive literature on military casualties and support for war, we know very little about public reactions to foreign civilian casualties. This article, based on representative sample surveys in the US and Britain, reports four survey experiments weaving information about civilian casualties into vignettes about Western military action. These produce consistent evidence of civilian casualty aversion: where death tolls were higher, support for force was invariably and significantly lower. Casualty effects were moderate in size but robust across our two cases and across different scenarios. They were also strikingly resistant to moderation by other factors manipulated in the experiments, such as the framing of casualties or their religious affiliation. The importance of numbers over even strongly humanizing frames points towards a utilitarian rather than a social-psychological model of casualty aversion. Either way, civilian casualties deserve a more prominent place in the literature on public support for war
Plasmas and Controlled Nuclear Fusion
Contains reports on eleven research projects split into three section.U. S. Atomic Energy Commission (Contract AT(30-1)-3980
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