52,521 research outputs found
Charge-transfer photodissociation of adsorbed molecules via electron image states
The 248nm and 193nm photodissociation of submonolayer quantities of CHBr
and CHI adsorbed on thin layers of n-hexane indicate that the dissociation
is caused by dissociative electron attachment from sub-vacuum level
photoelectrons created in the copper substrate. The characteristics of this
photodissociation-- translation energy distributions and coverage dependences
show that the dissociation is mediated by an image potential state which
temporarily traps the photoelectrons near the n-hexane--vacuum interface, and
then the charge transfers from this image state to the affinity level of a
co-adsorbed halomethane which then dissociates.Comment: submitted to Journal of Chemical Physic
NECAP 4.1: NASA's Energy-Cost Analysis Program fast input manual and example
NASA's Energy-Cost Analysis Program (NECAP) is a powerful computerized method to determine and to minimize building energy consumption. The program calculates hourly heat gain or losses taking into account the building thermal resistance and mass, using hourly weather and a response factor method. Internal temperatures are allowed to vary in accordance with thermostat settings and equipment capacity. NECAP 4.1 has a simplified input procedure and numerous other technical improvements. A very short input method is provided. It is limited to a single zone building. The user must still describe the building's outside geometry and select the type of system to be used
White primer permits a corrosion-resistant coating of minimum weight
White primer for coating 2219 aluminum alloy supplies a base for a top coating of enamel. A formulation of pigments and vehicle results in a primer with high corrosion resistance and minimum film thickness
Critical exponents of the pair contact process with diffusion
We study the pair contact process with diffusion (PCPD) using Monte Carlo
simulations, and concentrate on the decay of the particle density with
time, near its critical point, which is assumed to follow . This model is known for its slow
convergence to the asymptotic critical behavior; we therefore pay particular
attention to finite-time corrections. We find that at the critical point, the
ratio of and the pair density converges to a constant,
indicating that both densities decay with the same powerlaw. We show that under
the assumption , two of the critical exponents of
the PCPD model are and , consistent with
those of the directed percolation (DP) model
Worldsheet Instanton Corrections to the Kaluza-Klein Monopole
The Kaluza-Klein monopole is a well known object in both gravity and string
theory, related by T-duality to a "smeared" NS5-brane which retains the
isometry around the duality circle. As the true NS5-brane solution is localized
at a point on the circle, duality implies that the Kaluza-Klein monopole should
show some corresponding behavior. In this paper, we express the Kaluza-Klein
monopole as a gauged linear sigma model in two dimensions and show that
worldsheet instantons give corrections to its geometry. These corrections can
be understood as a localization in "winding space" which could be probed by
strings with winding charge around the circle.Comment: 20 pages, REVTeX, v2: minor equation correctio
Relative production rates of He, Be, C in astrophysical environments
We assume an environment of neutrons and -particles of given density
and temperature where nuclear syntheses into He, Be and C
are possible. We investigate the resulting relative abundance as a function of
density and temperature. When the relative abundance of -particles
is between 0.2 and 0.9, or larger than 0.9, the largest production
is Be or C, respectively. When He is mostly
frequently produced for temperatures above about 2 GK whereas the Be
production dominates at smaller temperatures.Comment: 5 pages, 4 figure
Role of Insects and Diseases in a Jack Pine Provenance Study
Two jack pine plantations were established at the Cloquet Forestry Center, Cloquet, Minnesota, in 1942 and 1943, using trees originating from 22 sites in the United States and 10 in Canada. From 1945 to 1953 the incidence of attack by insects and diseases was recorded individually for all trees, and in 1980-1981 the diameter and form of both living and dead trees were recorded. There were differences in the incidence of attack by the pests and in tree response to early injury among the various seed sources. In 1980 and in 1981 there were differences in tree form resulting from insect and both living and dead pest-free trees had the best form. The diameter increases from 1955 to 1980-1981 were almost identical for all categories with the exception of the dead pest-free trees which had the smallest diameters
How health systems in sub-Saharan Africa can benefit from tuberculosis and other infectious disease programmes.
Weak and dysfunctional health systems in low-income countries, particularly in sub-Saharan Africa, are recognised as major obstacles to attaining the health-related Millennium Development Goals by 2015. Some progress is being made towards achieving the targets of Millennium Development Goal 6 for tuberculosis (TB), HIV/AIDS and malaria, with the achievements largely resulting from clearly defined strategies and intervention delivery systems combined with large amounts of external funding. This article is divided into four main sections. The first highlights the crucial elements that are needed in low-income countries in sub-Saharan Africa to deliver good quality health care through general health systems. The second discusses the main characteristics of infectious disease and TB control programmes. The third illustrates how TB control and other infectious disease programmes can help to strengthen these components, particularly in human resources; infrastructure; procurement and distribution; monitoring, evaluation and supervision; leadership and stewardship. The fourth and final section looks at progress made to date at the international level in terms of policy and guidelines, with some specific suggestions about this might be moved forward at the national level. For TB and other infectious disease programmes to drive broad improvements in health care systems and patient care, the lessons that have been learnt must be consciously applied to the broader health system, and sufficient financial input and the engagement of all players are essential
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