214 research outputs found
Improved Bounds on the Phase Transition for the Hard-Core Model in 2-Dimensions
For the hard-core lattice gas model defined on independent sets weighted by
an activity , we study the critical activity
for the uniqueness/non-uniqueness threshold on the 2-dimensional integer
lattice . The conjectured value of the critical activity is
approximately . Until recently, the best lower bound followed from
algorithmic results of Weitz (2006). Weitz presented an FPTAS for approximating
the partition function for graphs of constant maximum degree when
where is the
infinite, regular tree of degree . His result established a certain
decay of correlations property called strong spatial mixing (SSM) on
by proving that SSM holds on its self-avoiding walk tree
where and is an ordering on the neighbors of vertex . As
a consequence he obtained that . Restrepo et al. (2011) improved Weitz's approach for
the particular case of and obtained that
. In this paper, we establish an upper bound for
this approach, by showing that, for all , SSM does not hold on
when . We also present a
refinement of the approach of Restrepo et al. which improves the lower bound to
.Comment: 19 pages, 1 figure. Polished proofs and examples compared to earlier
versio
Oral Plasmablastic Lymphoma: A clinicopathological study of 113 cases
https://drive.google.com/file/d/12WkwlN-xh9ZhZoahJ_c-N4zwuiLBZ0x8/view?usp=sharinghttps://drive.google.com/drive/folders/1Rm_GimQtumx7roigsBwBPMnhFTTUZ-UC?usp=sharinghttps://drive.google.com/drive/folders/1TtTOHdcYPzNddB4h2MCDaXeYTkkHn_v7?usp=sharin
Calcifying Odontogenic Cysts: A 20-year Retrospective Clinical and Radiological Review
https://drive.google.com/file/d/1ITFvU7cm3hNQyBRHV6LwRI47pgIWN37E/view?usp=sharinghttps://drive.google.com/drive/folders/1Rm_GimQtumx7roigsBwBPMnhFTTUZ-UC?usp=sharinghttps://drive.google.com/drive/folders/1TtTOHdcYPzNddB4h2MCDaXeYTkkHn_v7?usp=sharin
Seismology of the Sun : Inference of Thermal, Dynamic and Magnetic Field Structures of the Interior
Recent overwhelming evidences show that the sun strongly influences the
Earth's climate and environment. Moreover existence of life on this Earth
mainly depends upon the sun's energy. Hence, understanding of physics of the
sun, especially the thermal, dynamic and magnetic field structures of its
interior, is very important. Recently, from the ground and space based
observations, it is discovered that sun oscillates near 5 min periodicity in
millions of modes. This discovery heralded a new era in solar physics and a
separate branch called helioseismology or seismology of the sun has started.
Before the advent of helioseismology, sun's thermal structure of the interior
was understood from the evolutionary solution of stellar structure equations
that mimicked the present age, mass and radius of the sun. Whereas solution of
MHD equations yielded internal dynamics and magnetic field structure of the
sun's interior. In this presentation, I review the thermal, dynamic and
magnetic field structures of the sun's interior as inferred by the
helioseismology.Comment: To be published in the proceedings of the meeting "3rd International
Conference on Current Developments in Atomic, Molecular, Optical and Nano
Physics with Applications", December 14-16, 2011, New Delhi, Indi
Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments
Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made
available as an electronic reprint with the permission of ASM International. One print or electronic copy may
be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via
electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or
modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (“pop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor
Atmospheric Heating and Wind Acceleration: Results for Cool Evolved Stars based on Proposed Processes
A chromosphere is a universal attribute of stars of spectral type later than
~F5. Evolved (K and M) giants and supergiants (including the zeta Aurigae
binaries) show extended and highly turbulent chromospheres, which develop into
slow massive winds. The associated continuous mass loss has a significant
impact on stellar evolution, and thence on the chemical evolution of galaxies.
Yet despite the fundamental importance of those winds in astrophysics, the
question of their origin(s) remains unsolved. What sources heat a chromosphere?
What is the role of the chromosphere in the formation of stellar winds? This
chapter provides a review of the observational requirements and theoretical
approaches for modeling chromospheric heating and the acceleration of winds in
single cool, evolved stars and in eclipsing binary stars, including physical
models that have recently been proposed. It describes the successes that have
been achieved so far by invoking acoustic and MHD waves to provide a physical
description of plasma heating and wind acceleration, and discusses the
challenges that still remain.Comment: 46 pages, 9 figures, 1 table; modified and unedited manuscript;
accepted version to appear in: Giants of Eclipse, eds. E. Griffin and T. Ake
(Berlin: Springer
High-time Resolution Astrophysics and Pulsars
The discovery of pulsars in 1968 heralded an era where the temporal
characteristics of detectors had to be reassessed. Up to this point detector
integration times would normally be measured in minutes rather seconds and
definitely not on sub-second time scales. At the start of the 21st century
pulsar observations are still pushing the limits of detector telescope
capabilities. Flux variations on times scales less than 1 nsec have been
observed during giant radio pulses. Pulsar studies over the next 10 to 20 years
will require instruments with time resolutions down to microseconds and below,
high-quantum quantum efficiency, reasonable energy resolution and sensitive to
circular and linear polarisation of stochastic signals. This chapter is review
of temporally resolved optical observations of pulsars. It concludes with
estimates of the observability of pulsars with both existing telescopes and
into the ELT era.Comment: Review; 21 pages, 5 figures, 86 references. Book chapter to appear
in: D.Phelan, O.Ryan & A.Shearer, eds.: High Time Resolution Astrophysics
(Astrophysics and Space Science Library, Springer, 2007). The original
publication will be available at http://www.springerlink.co
Identifying the need for good practices in Health Technology Assessment : summary of the ISPOR HTA Council Working Group Report on Good Practices in HTA
The systematic use of evidence to inform healthcare decisions, particularly health technology assessment (HTA), has gained increased recognition. HTA has become a standard policy tool for informing decision makers who must manage the entry and use of pharmaceuticals, medical devices, and other technologies (including complex interventions) within health systems, for example, through reimbursement and pricing. Despite increasing attention to HTA activities, there has been no attempt to comprehensively synthesize good practices or emerging good practices to support populationbased decision-making in recent years. After the identification of some good practices through the release of the ISPOR Guidelines Index in 2013, the ISPOR HTA Council identified a need to more thoroughly review existing guidance. The purpose of this effort was to create a basis for capacity building, education, and improved consistency in approaches to HTA-informed decision-making. Our findings suggest that although many good practices have been developed in areas of assessment and some other key aspects of defining HTA processes, there are also many areas where good practices are lacking. This includes good practices in defining the organizational aspects of HTA, the use of deliberative processes, and measuring the impact of HTA. The extent to which these good practices are used and applied by HTA bodies is beyond the scope of this report, but may be of interest to future researchers
Effects of plant population density on cabbage (Brassica oleracea var. capitata L.) crop
Com a finalidade de avaliar o efeito da densidade de população de plantas sobre a cultura de repolho (Brassica cleraoea var, capitata L.), foi realizado um experimento no Campo Experimental do Setor de Horticultura da Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba, São Paulo, em um Latossol Roxo, Série Luiz de Queiroz, utilizando-se os espaçamentos de 0,60 mx 0,80 m; 0,60 m x 0,65 m; 0,60 m x 0,45 m; 0,60 m x 0,30 m e 0,60 m x 0,15 m. À medida em que se aumentou a densidade de população, houve as seguintes alterações na planta de repolho: mudança de for mato chato da "cabeça" para cônico, redução do numero de folhas, tamanho (peso, volume e diâmetros transversal e longitudinal) , aumento na densidade da "cabeça" (peso/volume) e aumento na porcentagem de plantas que não produziram "cabeça.In order to study the effects of plant population density on cabbage crop (Brassica oleracea var-. capitata), an experiment using different spacing (0,60 m x 0.80 m, 0.60 m x 0.65 m, 0.60mx0.45m, 0.60 m x 0.30 m, and 0.60mx 0.15m) was carried out. There were the following changes in cabbage plants due to increasing population density: plant head became conical: number and size (weight, volume and diameters) of leaves decreased; density (weight/volume) and percentage of plants forming no head increased
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