5,656 research outputs found
What Do CFTs Tell Us About Anti-de Sitter Spacetimes?
The AdS/CFT conjecture relates quantum gravity on Anti-de Sitter (AdS) space
to a conformal field theory (CFT) defined on the spacetime boundary. We
interpret the CFT in terms of natural analogues of the bulk S-matrix. Our first
approach finds the bulk S-matrix as a limit of scattering from an AdS bubble
immersed in a space admitting asymptotic states. Next, we show how the
periodicity of geodesics obstructs a standard LSZ prescription for scattering
within global AdS. To avoid this subtlety we partition global AdS into patches
within which CFT correlators reconstruct transition amplitudes of AdS states.
Finally, we use the AdS/CFT duality to propose a large N collective field
theory that describes local, perturbative supergravity. Failure of locality in
quantum gravity should be related to the difference between the collective 1/N
expansion and genuine finite N dynamics.Comment: 33 pages, 7 figures, uses harvmac, reference adde
Employment, Income and Labour Supply Decision of Rural Households : An Economic Analysis of MGNREGS in Tamil Nadu
In India, Mahatma Gandhi National Rural Employment Guarantee Scheme (MGMGNREGS) is one of the major rural development programmes. It provides guaranteed employment to the rural households for 100 days in a year. This paper has attempted to find out the employment status, income and labour supply decision of the participants and non-participants of MGNREGS in Tamil Nadu. It has also studied the household nutritional security of these households. The study has revealed that the number of migrants in the family, number of livestock units owned, and number of person-days employed in agriculture, nonagriculture and MGNREGS are significantly influenced by the household income of the participants and non-participants of MGNREGS. The analysis of household food-security has shown that the expenditure for all commodities, viz. leisure, cereals, pulses, oils, fruits & vegetables, milk, chicken and fish are positive and significant in the case of MGNREGS participants, whereas the expenditure variable is significant only for two commodities, viz. cereals and oils in case of MGNREGS non-participants. It shows that the MGNREGS participants consume more high-value commodities like milk, chicken and fish, as compared to MGNREGS non-participants. The labour supply decision of sample respondents has shown that the elasticity of labour supply with respect to wage rate is more than one in both participants and non-participants of MGNREGS, indicating that an one per cent increase in wage rate increases labour supply by 1.92 per cent and 2.36 per cent, respectively. In addition, as the number of dependents increases, the household increases labour supply to derive additional income to meet the increased household expenditures. An interesting and encouraging observation is that the scheme has reduced the migration of people from rural to urban areas.MGNREGS, employment, income, labour supply, Agricultural and Food Policy, J21, J22, H23, I31,
What we don't know about time
String theory has transformed our understanding of geometry, topology and
spacetime. Thus, for this special issue of Foundations of Physics commemorating
"Forty Years of String Theory", it seems appropriate to step back and ask what
we do not understand. As I will discuss, time remains the least understood
concept in physical theory. While we have made significant progress in
understanding space, our understanding of time has not progressed much beyond
the level of a century ago when Einstein introduced the idea of space-time as a
combined entity. Thus, I will raise a series of open questions about time, and
will review some of the progress that has been made as a roadmap for the
future.Comment: 15 pages; Essay for a special issue of Foundations of Physics
commemorating "Forty years of string theory
Phonon-induced linewidths of graphene electronic states
The linewidths of the electronic bands originating from the electron-phonon
coupling in graphene are analyzed based on model tight-binding calculations and
experimental angle-resolved photoemission spectroscopy (ARPES) data. Our
calculations confirm the prediction that the high-energy optical phonons
provide the most essential contribution to the phonon-induced linewidth of the
two upper occupied bands near the -point. For larger
binding energies of these bands, as well as for the band, we find
evidence for a substantial lifetime broadening from interband scattering and , respectively, driven by the
out-of-plane ZA acoustic phonons. The essential features of the calculated
band linewidths are in agreement with recent published ARPES data [F.
Mazzola et al., Phys.~Rev.~B. 95, 075430 (2017)] and of the band
linewidth with ARPES data presented here.Comment: 7 pages, 4 figure
Deep Model Compression: Distilling Knowledge from Noisy Teachers
The remarkable successes of deep learning models
across various applications have resulted in the design of
deeper networks that can solve complex problems. How-
ever, the increasing depth of such models also results in
a higher storage and runtime complexity, which restricts
the deployability of such very deep models on mobile and
portable devices, which have limited storage and battery
capacity. While many methods have been proposed for deep
model compression in recent years, almost all of them have
focused on reducing storage complexity. In this work, we
extend the teacher-student framework for deep model com-
pression, since it has the potential to address runtime and
train time complexity too. We propose a simple method-
ology to include a noise-based regularizer while training
the student from the teacher, which provides a healthy im-
provement in the performance of the student network. Our
experiments on the CIFAR-10, SVHN and MNIST datasets
show promising improvement, with the best performance on
the CIFAR-10 dataset. We also conduct a comprehensive
empirical evaluation of the proposed method under related
settings on the CIFAR-10 dataset to show the promise of the
proposed approach
Effect of handball specific aerobic training on body composition and VO2 max of male handball players
The aim of this study is to assess the effect of four and eight weeks small-sided handball game on body composition and VO2 max of male handball players. Sixteen (16) male university handball players volunteered to act as subjects and were randomly assigned to small sided handball game group (SSHG) and control group (CG). Small-sided handball game was administered three days in a week for eight weeks. Subjects were measured on percent body fat, lean body mass and VO2 max on three occasions first before administration of training as pretest, after four weeks of training as mid test and after eight weeks of training as post-test. A two-way repeated measure ANOVA with last factor repeated revealed that percent body fat and lean body mass remained unaltered after four and eight weeks of training. However, VO2 max improved (p<0.05). VO2 max showed an improvement of 4.75% after four weeks and 8.83% % after eight weeks of small-sided handball game training in male handball players. This study shows that small-sided handball game (4 vs. 4) is effective in improving aerobic capacity in four and eight weeks of training but body composition elicited no changes
Single genome retrieval of context-dependent variability in mutation rates for human germline
Abstract
Background
Accurate knowledge of the core components of substitution rates is of vital importance to understand genome evolution and dynamics. By performing a single-genome and direct analysis of 39,894 retrotransposon remnants, we reveal sequence context-dependent germline nucleotide substitution rates for the human genome.
Results
The rates are characterised through rate constants in a time-domain, and are made available through a dedicated program (Trek) and a stand-alone database. Due to the nature of the method design and the imposed stringency criteria, we expect our rate constants to be good estimates for the rates of spontaneous mutations. Benefiting from such data, we study the short-range nucleotide (up to 7-mer) organisation and the germline basal substitution propensity (BSP) profile of the human genome; characterise novel, CpG-independent, substitution prone and resistant motifs; confirm a decreased tendency of moieties with low BSP to undergo somatic mutations in a number of cancer types; and, produce a Trek-based estimate of the overall mutation rate in human.
Conclusions
The extended set of rate constants we report may enrich our resources and help advance our understanding of genome dynamics and evolution, with possible implications for the role of spontaneous mutations in the emergence of pathological genotypes and neutral evolution of proteomes
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