680 research outputs found
Of Genes and Antigens: The Inheritance of Psoriasis
Psoriasis is one of a number of autoimmune diseases that display significant HLA associations. In particular, individuals with onset of disease prior to 40 years of age display striking associations with HLA-Cw6 and are much more likely to have a positive family for psoriasis. However, only about 10% of Cw6-positive individuals develop disease, suggesting that other genetic and/or environmental factors must be involved. Several compelling lines of epidemiologic evidence indicate that psoriasis susceptibility is inherited, albeit not in a simple monogenic fashion, and that genetic, rather than environmental, factors are primarily responsible for the variability in inheritance of psoriasis. Taken together, these observations suggest that one or more loci in addition to HLA are necessary for the development of psoriasis. The number of additional loci is likely to be small, because i) the disease is very common ii) substantial excess risk of psoriasis is observed in first degree relatives, and iii) nevoid variants of psoriasis have been reported, suggestive of somatic mutation of a single gene during development. The substantial homogeneity of the psoriatic phenotype and the clear evidence for increased HLA association and heritability in juvenile onset disease indicate that despite its complexity, psoriasis is a common disease whose etiology is amenable to elucidation through the techniques of modern molecular genetics. J Invest Dermatol 103:150S-153S, 199
Nonadiabatic pumping in classical and quantum chaotic scatterers
We study directed transport in periodically forced scattering systems in the
regime of fast and strong driving where the dynamics is mixed to chaotic and
adiabatic approximations do not apply. The model employed is a square potential
well undergoing lateral oscillations, alternatively as two- or single-parameter
driving. Mechanisms of directed transport are analyzed in terms of asymmetric
irregular scattering processes. Quantizing the system in the framework of
Floquet scattering theory, we calculate directed currents on basis of
transmission and reflection probabilities obtained by numerical wavepacket
scattering. We observe classical as well as quantum transport beyond linear
response, manifest in particular in a non-zero current for single-parameter
driving where according to adiabatic theory, it should vanish identically.Comment: 13 pages, 8 figure
Small Disks and Semiclassical Resonances
We study the effect on quantum spectra of the existence of small circular
disks in a billiard system. In the limit where the disk radii vanish there is
no effect, however this limit is approached very slowly so that even very small
radii have comparatively large effects. We include diffractive orbits which
scatter off the small disks in the periodic orbit expansion. This situation is
formally similar to edge diffraction except that the disk radii introduce a
length scale in the problem such that for wave lengths smaller than the order
of the disk radius we recover the usual semi-classical approximation; however,
for wave lengths larger than the order of the disk radius there is a
qualitatively different behaviour. We test the theory by successfully
estimating the positions of scattering resonances in geometries consisting of
three and four small disks.Comment: Final published version - some changes in the discussion and the
labels on one figure are correcte
Alleviating poverty through Islamic microfinance: factors and measures of financial performance, and roles of Islamic values and financial policies
Indonesia has a strong presence of microfinance sector with the number of Islamic Microfinance Institutions (IMFIs) estimated to be around 5,000 currently. Microfinance is an effective tool in alleviating poverty in Indonesia due to the limited access to financial services by the poor who accounted for approximately 96 million Indonesians (or 37% of the total population), living on less than USD 1.90 a day. In the absence of collateral and steady income, the poor are considered too risky to be given credit facilities by the formal financial services providers and living in remote areas has also limited their access to formal financial services. This study aims to examine the poverty alleviation efforts from the perspective of the IMFIs in view of their direct involvement in the process and having rich information about financial issues facing the borrowers. The managers also understand about financial inclusion agenda as well as financial guidelines and regulations issued by the relevant authorities. A total of 34 managers of Baitulmaal Wa Tamwil (BMTs), which registered under the Sharia Cooperative Centre (INKOPSYAH) are taken as respondents from the Jakarta, Bogor, Depok, Tangerang and Bekasi (JABODETABEK) areas. The first instrument was a survey questionnaire, and the second one was an in-depth interview to outline data related to the model design. The findings of this research are expected to contribute to better decision-making for the BMTs to further enhance its role in alleviating poverty. The findings also elaborate several dimensions to improving financial inclusion among the poor including providing financial services, implementing Islamic principles, significant policies, community-based framework concept and training financial education. This research highlights the need for a variety of strategies to warrant success of poverty alleviation efforts by BMT
Geometry and material effects in Casimir physics - Scattering theory
We give a comprehensive presentation of methods for calculating the Casimir
force to arbitrary accuracy, for any number of objects, arbitrary shapes,
susceptibility functions, and separations. The technique is applicable to
objects immersed in media other than vacuum, to nonzero temperatures, and to
spatial arrangements in which one object is enclosed in another. Our method
combines each object's classical electromagnetic scattering amplitude with
universal translation matrices, which convert between the bases used to
calculate scattering for each object, but are otherwise independent of the
details of the individual objects. This approach, which combines methods of
statistical physics and scattering theory, is well suited to analyze many
diverse phenomena. We illustrate its power and versatility by a number of
examples, which show how the interplay of geometry and material properties
helps to understand and control Casimir forces. We also examine whether
electrodynamic Casimir forces can lead to stable levitation. Neglecting
permeabilities, we prove that any equilibrium position of objects subject to
such forces is unstable if the permittivities of all objects are higher or
lower than that of the enveloping medium; the former being the generic case for
ordinary materials in vacuum.Comment: 44 pages, 11 figures, to appear in upcoming Lecture Notes in Physics
volume in Casimir physic
Floquet Formalism of Quantum Pumps
We review Floquet formalism of quantum electron pumps. In the Floquet
formalism the quantum pump is regarded as a time dependent scattering system,
which allows us to go beyond the adiabatic limit. It can be shown that the
well-known adiabatic formula given by Brouwer can be derived from the adiabatic
limit of Floquet formalism. We compare various physical properties of the
quantum pump both in the adiabatic and in the non-adiabatic regime using the
Floquet theory.Comment: Latex2e 16 pages, 6 figures. A review paper to appear in Int. J. Mod.
Phys.
Investigating the uses of corporate reputation and its effects on brand segmentation, brand differentiation and brand positioning: evidence from the Taiwanese pharmaceutical industry
This study advances current knowledge on building a brand strategy that includes corporate reputation. It employs three theories – value creation, strategic resources and corporate communication – to study the uses of corporate reputation and its effect on brand segmentation, brand differentiation and brand positioning. In the context of the Taiwanese pharmaceutical industry, a sequential mixed method approach is applied and data are analyzed using PLS SEM. Findings demonstrate the relative impacts of three uses of corporate reputation (value creation, strategic resources and corporate communication) on brand image strategy (brand segmentation, brand differentiation and brand positioning) and the implications are evaluated. This study discovers that the inclusion of medicine prices is necessary and that it negatively moderates the impact of the overall uses of corporate reputation on overall brand image strategy. This research contributes empirically as one of the few that tests reputation-and-branding-building models outside the USA and Europe
Pumping angular momentum by driven chaotic scattering
Chaotic scattering with an internal degree of freedom and the possibility to
generate directed transport of angular momentum is studied in a specific model,
a magnetic dipole moving in a periodically modulated magnetic field confined to
a compact region in space. We show that this system is an irregular scatterer
in large parts of its parameter space. If in addition all spatio-temporal
symmetries are broken, directed transport of mass as well as angular momentum
occurs. The sensitive parameter dependence of the corresponding currents
includes frequent sign reversals. Zeros of either quantity entail the exclusive
occurrence of the other and thus give rise in particular to angular-momentum
separation without mass transport as a classical analogue of spin-polarized
currents.Comment: 17 pages, 12 figure
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