2,099 research outputs found
Determinants of the structure of U.S. foreign trade, 1958-1976
The Heckscher-Ohlin model with three direct-factor inputs is borne out for U.S. net exports of manufactures in annual cross-section regressions for 1958-1976. The coefficient on unskilled labor became significantly more negative over the period, and there is evidence that the negative sign on physical capital may reflect the inclusion of natural resource industries. Further analysis based upon 1960 and 1970 census years suggests the importance as well of skill and technological variables. Calculations of the total factor requirements of U.S. trade uphold the Leontief paradox for 1958 but not for 1972.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24383/1/0000653.pd
On renormalization group flows and the a-theorem in 6d
We study the extension of the approach to the a-theorem of Komargodski and
Schwimmer to quantum field theories in d=6 spacetime dimensions. The dilaton
effective action is obtained up to 6th order in derivatives. The anomaly flow
a_UV - a_IR is the coefficient of the 6-derivative Euler anomaly term in this
action. It then appears at order p^6 in the low energy limit of n-point
scattering amplitudes of the dilaton for n > 3. The detailed structure with the
correct anomaly coefficient is confirmed by direct calculation in two examples:
(i) the case of explicitly broken conformal symmetry is illustrated by the free
massive scalar field, and (ii) the case of spontaneously broken conformal
symmetry is demonstrated by the (2,0) theory on the Coulomb branch. In the
latter example, the dilaton is a dynamical field so 4-derivative terms in the
action also affect n-point amplitudes at order p^6. The calculation in the
(2,0) theory is done by analyzing an M5-brane probe in AdS_7 x S^4.
Given the confirmation in two distinct models, we attempt to use dispersion
relations to prove that the anomaly flow is positive in general. Unfortunately
the 4-point matrix element of the Euler anomaly is proportional to stu and
vanishes for forward scattering. Thus the optical theorem cannot be applied to
show positivity. Instead the anomaly flow is given by a dispersion sum rule in
which the integrand does not have definite sign. It may be possible to base a
proof of the a-theorem on the analyticity and unitarity properties of the
6-point function, but our preliminary study reveals some difficulties.Comment: 41 pages, 5 figure
Infrastructures and Installation of the Compact Muon Solenoid Data Acquisition at CERN
At the time of this paper, all hardware elements of the CMS Data Acquisition System have been installed and commissioned both in the underground and surface areas. This paper describes in detail the infrastructures and the different steps that were necessary from the very beginning when the underground control rooms and surface building were building sites to a working system collecting data fragment from ~650 sources and sending them to surface for assembly and analysis
Predictors of Unrecognized HIV Infection Among Poor and Ethnic Men Who Have Sex with Men in Los Angeles
This study evaluates associations between unrecognized HIV infection and demographic factors, internalized homonegativity, drug use, and sexual behaviors among HIV positive men who have sex with men (MSM). We analyzed data from 347 HIV positive participants from the Los Angeles site for NIDAâs Sexual Acquisition and Transmission of HIV-Cooperative Agreement Program. Participants were HIV positive MSM and MSM/W and predominantly African American (36.0%) or Latino (38.7%), and unemployed (82.8%). Results from a multivariate logistic regression suggest that, compared to HIV positive participants who correctly reported their HIV positive status, being African-American (OR: 9.81, CI: 1.2â77.9) or Latino (OR: 10.92, CI: 1.3â88.4) rather than White, MSM/W rather than MSM (OR: 3.24, CI: 1.09â9.62), and having higher homonegativity scores (OR: 1.22, CI: 1.02â1.4) is associated with unrecognized HIV infection, controlling for age, education, and homelessness. Findings provide some immediate evidence to help craft HIV prevention interventions
The CMS High Level Trigger System
The CMS Data Acquisition (DAQ) System relies on a purely software driven High Level Trigger (HLT) to reduce the full Level-1 accept rate of 100 kHz to approximately 100 Hz for archiving and later offline analysis. The HLT operates on the full information of events assembled by an event builder collecting detector data from the CMS front-end systems. The HLT software consists of a sequence of reconstruction and filtering modules executed on a farm of O(1000) CPUs built from commodity hardware. This paper presents the architecture of the CMS HLT, which integrates the CMS reconstruction framework in the online environment. The mechanisms to configure, control, and monitor the Filter Farm and the procedures to validate the filtering code within the DAQ environment are described
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