943 research outputs found
Higher Spin Black Holes from CFT
Higher spin gravity in three dimensions has explicit black holes solutions,
carrying higher spin charge. We compute the free energy of a charged black hole
from the holographic dual, a 2d CFT with extended conformal symmetry, and find
exact agreement with the bulk thermodynamics. In the CFT, higher spin
corrections to the free energy can be calculated at high temperature from
correlation functions of W-algebra currents.Comment: 24 pages; v2 reference adde
Nonlinear W(infinity) Algebra as Asymptotic Symmetry of Three-Dimensional Higher Spin Anti-de Sitter Gravity
We investigate the asymptotic symmetry algebra of (2+1)-dimensional higher
spin, anti-de Sitter gravity. We use the formulation of the theory as a
Chern-Simons gauge theory based on the higher spin algebra hs(1,1). Expanding
the gauge connection around asymptotically anti-de Sitter spacetime, we specify
consistent boundary conditions on the higher spin gauge fields. We then study
residual gauge transformation, the corresponding surface terms and their
Poisson bracket algebra. We find that the asymptotic symmetry algebra is a
nonlinearly deformed W(infinity) algebra with classical central charges. We
discuss implications of our results to quantum gravity and to various
situations in string theory.Comment: 25 pages, no figure; v2. minor corrections, references added, v3.
JHEP published versio
Who fits into the digital workplace? mapping digital self-efficacy and agility onto psychological traits
Abstract: Todayβs rapidly changing and volatile markets demand a novel set of skills from organizations and employees that allows them to agilely adapt to and surmount the ever-evolving challenges posed by the ongoing development of digital technologies and changes in market conditions. Previous research conducted on structured workplaces using traditional industrialist paradigms had established an ideal composition of employee traits. However, todayβs contrasting fast-paced environments may have made those profiles obsolete, prompting the need to identify a profile of personalities and interests that enables organizations to assemble a workforce high in digital self-efficacy, which fundamentally drives organizationsβ agility. We proposed and evaluated such a model by conducting two studies at international (Study 1, N = 309) and French (Study 2, N = 1,025) publicly traded organizations. The results indicate the personality dimensions openness to experience and emotional stability and investigative and realistic vocational interests are predispositions for the development of digital self-efficacy. Furthermore, we found corroborative evidence for digital self-efficacy to facilitate workforce agility. These findings offer novel insights into those individual psychological traits that foster an agile workforce and make it well-equipped to face the challenges of rapidly changing digital business environments today and in the future
On effective actions of BPS branes and their higher derivative corrections
We calculate in detail the disk level S-matrix element of one Ramond-Ramond
field and three gauge field vertex operators in the world volume of BPS branes,
to find four gauge field couplings to all orders of up to on-shell
ambiguity. Then using these infinite couplings we find that the massless pole
of the field theory amplitude is exactly equal to the massless pole S-matrix
element of this amplitude for the case to all orders of .
Finally we show that the infinite massless poles and the contact terms of this
amplitude for the case can be reproduced by the Born-Infeld action and
the Wess-Zumino actions and by their higher derivative corrections.Comment: 26 pages, 2 figures, minor corrections,references added and version
published in JHE
STUDI EKSPERIMENTAL KARAKTERISTIK KUAT TEKAN DAN KARAKTERISTIK PEMBAKARAN BRIKET DAUN CENGKEH DAN JERAMI PADI
Penelitian ini mempelajari tentang karakteristik kuat tekan dan karakteristik
pembakaran briket daun cengkeh dan jerami padi. Pembriketan dilakukan dengan
menggunakan mesin pres hidrolik dengan tekanan pembriketan sebesar 450
kg/cm2, dengan bahan pengikat dan tanpa bahan pengikat. Bahan pengikat yang
digunakan adalah lem kanji dengan kadar 5 %. Briket berbentuk silinder dengan
diameter sekitar 3 cm dan tinggi 5 cm. Variasi parameter pembriketan yang
digunakan adalah ukuran butir 20, 40 dan 80 mesh, kadar air 15 %, 20 % dan 25
%, serta suhu pembriketan sebesar 60 oC, 80 oC, 100 oC dan 120 oC. Uji
pembakaran dilakukan dalam tungku berbentuk tabung horisontal berdiameter
dalam 170 mm. Variasi perameter uji pembakaran yang digunakan adalah
kecepatan aliran udara sebesar 0,6 m/s; 0,8 m/s; 1,0 m/s dan 1,2 m/s serta variasi
ukuran butir sebesar 20, 40, dan 80 mesh. Suhu pembriketan berpengaruh
signifikan terhadap peningkatan kuat tekan briket. Dari hasil uji pembakaran
dapat ditentukan besarnya laju pembakaran, profil suhu pembakaran, nilai energi
aktivasi (E ), konstanta Arrhenius (A), dan emisi CO. Dari semua percobaan,
kadar emisi CO puncak lebih dari 400 ppm.
Kata kunci: kuat tekan, daun cengkeh, jerami, bahan pengikat, ukuran butir,
suhu pembriketan, kadar air, laju pembakaran, energi aktivasi,
emisi CO.
Caloric Restriction Alters the Metabolic Response to a Mixed-Meal: Results from a Randomized, Controlled Trial
OBJECTIVES: To determine if caloric restriction (CR) would cause changes in plasma metabolic intermediates in response to a mixed meal, suggestive of changes in the capacity to adapt fuel oxidation to fuel availability or metabolic flexibility, and to determine how any such changes relate to insulin sensitivity (S(I)). METHODS: Forty-six volunteers were randomized to a weight maintenance diet (Control), 25% CR, or 12.5% CR plus 12.5% energy deficit from structured aerobic exercise (CR+EX), or a liquid calorie diet (890 kcal/d until 15% reduction in body weight)for six months. Fasting and postprandial plasma samples were obtained at baseline, three, and six months. A targeted mass spectrometry-based platform was used to measure concentrations of individual free fatty acids (FFA), amino acids (AA), and acylcarnitines (AC). S(I) was measured with an intravenous glucose tolerance test. RESULTS: Over three and six months, there were significantly larger differences in fasting-to-postprandial (FPP) concentrations of medium and long chain AC (byproducts of FA oxidation) in the CR relative to Control and a tendency for the same in CR+EX (CR-3 month Pβ=β0.02; CR-6 month Pβ=β0.002; CR+EX-3 month Pβ=β0.09; CR+EX-6 month Pβ=β0.08). After three months of CR, there was a trend towards a larger difference in FPP FFA concentrations (Pβ=β0.07; CR-3 month Pβ=β0.08). Time-varying differences in FPP concentrations of AC and AA were independently related to time-varying S(I) (P<0.05 for both). CONCLUSIONS: Based on changes in intermediates of FA oxidation following a food challenge, CR imparted improvements in metabolic flexibility that correlated with improvements in S(I). TRIAL REGISTRATION: ClinicalTrials.gov NCT00099151
Single neuron transcriptomics identify SRSF/ SR protein B52 as a regulator of axon growth and Choline acetyltransferase splicing.
We removed single identified neurons from living Drosophila embryos to gain insight into the transcriptional control of developing neuronal networks. The microarray analysis of the transcriptome of two sibling neurons revealed seven differentially expressed transcripts between both neurons (threshold: log(2)1.4). One transcript encodes the RNA splicing factor B52. Loss of B52 increases growth of axon branches. B52 function is also required for Choline acetyltransferase (ChATβ) splicing. At the end of embryogenesis, loss of B52 function impedes splicing of ChAT, reduces acetylcholine synthesis, and extends the period of uncoordinated muscle twitches during larval hatching. ChAT regulation by SRSF proteins may be a conserved feature since changes in SRSF5 expression and increased acetylcholine levels in brains of bipolar disease patients have been reported recently
The Evolution of Compact Binary Star Systems
We review the formation and evolution of compact binary stars consisting of
white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and
BHs are thought to be the primary astrophysical sources of gravitational waves
(GWs) within the frequency band of ground-based detectors, while compact
binaries of WDs are important sources of GWs at lower frequencies to be covered
by space interferometers (LISA). Major uncertainties in the current
understanding of properties of NSs and BHs most relevant to the GW studies are
discussed, including the treatment of the natal kicks which compact stellar
remnants acquire during the core collapse of massive stars and the common
envelope phase of binary evolution. We discuss the coalescence rates of binary
NSs and BHs and prospects for their detections, the formation and evolution of
binary WDs and their observational manifestations. Special attention is given
to AM CVn-stars -- compact binaries in which the Roche lobe is filled by
another WD or a low-mass partially degenerate helium-star, as these stars are
thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure
Current drinking and health-risk behaviors among male high school students in central Thailand
<p>Abstract</p> <p>Background</p> <p>Alcohol drinking is frequently related to behavioral problems, which lead to a number of negative consequences. This study was to evaluate the characteristics of male high school students who drink, the drinking patterns among them, and the associations between current drinking and other health risk behaviors which focused on personal safety, violence-related behaviors, suicide and sexual behaviors.</p> <p>Method</p> <p>A cross-sectional study was conducted to explore current alcohol drinking and health-risk behaviors among male high school students in central Thailand. Five thousand one hundred and eighty four male students were classified into 2 groups according to drinking in the previous 30 days (yes = 631, no = 4,553). Data were collected by self-administered, anonymous questionnaire which consisted of 3 parts: socio-demographic factors, health-risk behaviors and alcohol drinking behavior during the past year from December 2007 to February 2008.</p> <p>Results</p> <p>The results showed that the percent of current drinking was 12.17. Most of them were 15-17 years (50.21%). Socio-demographic factors such as age, educational level, residence, cohabitants, grade point average (GPA), having a part time job and having family members with alcohol/drug problems were significantly associated with alcohol drinking (p < 0.05). Multiple logistic regression analysis, after adjusting for socio-demographic factors, revealed that health-risk behavioral factors were associated with current alcohol consumption: often drove after drinking alcohol (OR = 3.10, 95% CI = 1.88-5.12), often carried a weapon (OR = 3.51, 95% CI = 2.27-5.42), often got into a physical fight without injury (OR = 3.06, 95% CI = 1.99-4.70), dating violence (OR = 2.58, 95% CI = 1.79-3.71), seriously thought about suicide (OR = 2.07, 95% CI = 1.38-3.11), made a suicide plan (OR = 2.10, 95% CI = 1.43-3.08), ever had sexual intercourse (OR = 5.62, 95% CI = 4.33-7.29), alcohol or drug use before last sexual intercourse (OR = 2.55, 95% CI = 1.44-4.53), and got someone pregnant (OR = 3.99, 95% CI = 1.73-9.25).</p> <p>Conclusions</p> <p>An increased risk of health-risk behaviors, including driving vehicles after drinking, violence-related behaviors, sad feelings and attempted suicide, and sexual behaviors was higher among drinking students that led to significant health problems. Effective intervention strategies (such as a campaign mentioning the adverse health effects and social consequences to the risk groups, and encouraging parental and community efforts to prevent drinking) among adolescents should be implemented to prevent underage drinking and adverse consequences.</p
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of βs = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTβ₯20 GeV and pseudorapidities {pipe}Ξ·{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}Ξ·{pipe}<0. 8) for jets with 60β€pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2β€{pipe}Ξ·{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. Β© 2013 CERN for the benefit of the ATLAS collaboration
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