959 research outputs found
Domain Adaptation for Statistical Classifiers
The most basic assumption used in statistical learning theory is that
training data and test data are drawn from the same underlying distribution.
Unfortunately, in many applications, the "in-domain" test data is drawn from a
distribution that is related, but not identical, to the "out-of-domain"
distribution of the training data. We consider the common case in which labeled
out-of-domain data is plentiful, but labeled in-domain data is scarce. We
introduce a statistical formulation of this problem in terms of a simple
mixture model and present an instantiation of this framework to maximum entropy
classifiers and their linear chain counterparts. We present efficient inference
algorithms for this special case based on the technique of conditional
expectation maximization. Our experimental results show that our approach leads
to improved performance on three real world tasks on four different data sets
from the natural language processing domain
R&D Sourcing, Joint Ventures and Innovation: A Multiple Indicators Approach
This paper reexamines the limits of the firm in Research and Development (R&D). Using evidence drawn from industrial laboratories we study the causes and effects of R&D sourcing. We begin with the causes of sourcing, finding that Research Joint Ventures (RJVs), the option to purchase and acquire, and research with federal government contribute to sourced R&D. We then consider the effects of sourcing, RJVs, and the firm's internal research on innovation, as defined by patents and new products. Our results are that sourcing has little effect on innovation, but that RJVs and internal research increase innovation. This suggests specialization: cost saving is the primary motivation for sourcing, while innovation is the primary motivation for RJVs and internal research. Therefore, shared R&D comes in several varieties: R&D sourcing is not concerned with innovation, but consistent with their purpose, RJVs are instrumental in jointly commercializing the research of different firms.
Non-unitary Conformal Field Theory and Logarithmic Operators for Disordered Systems
We consider the supersymmetric approach to gaussian disordered systems like
the random bond Ising model and Dirac model with random mass and random
potential. These models appeared in particular in the study of the integer
quantum Hall transition. The supersymmetric approach reveals an osp(2/2)_1
affine symmetry at the pure critical point. A similar symmetry should hold at
other fixed points. We apply methods of conformal field theory to determine the
conformal weights at all levels. These weights can generically be negative
because of non-unitarity. Constraints such as locality allow us to quantize the
level k and the conformal dimensions. This provides a class of (possibly
disordered) critical points in two spatial dimensions. Solving the
Knizhnik-Zamolodchikov equations we obtain a set of four-point functions which
exhibit a logarithmic dependence. These functions are related to logarithmic
operators. We show how all such features have a natural setting in the
superalgebra approach as long as gaussian disorder is concerned.Comment: Latex, 20 pages, one figure. Version accepted for publication in
Nuclear Physics B, minor correction
Positive surgical margins in nephron-sparing surgery; the great unknown
There is a currently a general trend towards organ-preserving surgery, and urology is no exception. Specifically, nephron-sparing surgery (NSS) has gained general acceptance for T1a renal cell carcinoma (guidelines recommendations). Moreover T1b, T2 and even T3 stage tumors have been included on the nephron sparing list at some centers. An unresolved issue is that of positive surgical margins (PSM), not only their detection but also the implications for follow up and treatment. This paper highlights data available on risk factors for PSM, their clinical relevance, and possible therapeutic consequences.
From the surgeon’s viewpoint, NSS is a daring and risky surgical procedure. Urological guidelines stress the importance of NSS, and thus the trend is moving in that direction. Unresolved, however, is the problem of PSM. Trifecta, MIC, and pentafecta are applicable concepts which attempt to define the optimal endpoint of NSS, but further elaboration is necessary. Specifically, research needs to focus less on the concept of definitive margins and more on their identification and avoidance. Although some studies suggest that PSMs do not influence overall survival rate, the basic idea of preserving tissue that is not cancerous leads to further medical, social, and psychological considerations
A STUDY ON THE RETURN ON EQUITY FOR THE ROMANIAN INDUSTRIAL COMPANIES
In this paper, a study on a sample of 73 Romanian companies operating in industries was conducted. The survey covered the year 2008 and was based on data extracted from annual financial statements of the companies from the sample. Starting from a number of representative papers in the field, there were identified the influence factors of the return on equity and the quantifiable ones were hold, respectively the operating profit margin, the asset turnover and the financial leverage. These financial rates, together with the return on equity, have been determined for the entire population of enterprises from the sample. Subsequently was tested the statistical correlation between the level of influence factors and the return on equity. The results obtained partially confirmed the hypotheses set when starting the research, but have also denied some of them.return on equity, net profit, equity, operating profit margin, asset turnover,financial leverage
Multiple cyclotron line-forming regions in GX 301-2
We present two observations of the high-mass X-ray binary GX 301-2 with
NuSTAR, taken at different orbital phases and different luminosities. We find
that the continuum is well described by typical phenomenological models, like a
very strongly absorbed NPEX model. However, for a statistically acceptable
description of the hard X-ray spectrum we require two cyclotron resonant
scattering features (CRSF), one at ~35 keV and the other at ~50 keV. Even
though both features strongly overlap, the good resolution and sensitivity of
NuSTAR allows us to disentangle them at >=99.9% significance. This is the first
time that two CRSFs are seen in GX 301-2. We find that the CRSFs are very
likely independently formed, as their energies are not harmonically related
and, if it were a single line, the deviation from a Gaussian shape would be
very large. We compare our results to archival Suzaku data and find that our
model also provides a good fit to those data. We study the behavior of the
continuum as well as the CRSF parameters as function of pulse phase in seven
phase bins. We find that the energy of the 35 keV CRSF varies smoothly as
function of phase, between 30-38 keV. To explain this variation, we apply a
simple model of the accretion column, taking the altitude of the line-forming
region, the velocity of the in-falling material, and the resulting relativistic
effects into account. We find that in this model the observed energy variation
can be explained simply due to a variation of the projected velocity and
beaming factor of the line forming region towards us.Comment: 18 pages, 10 figures, accepted for publication in A&
Некоторые аспекты терапии кандидоза полости рта
Catedra Stomatologie terapeutică, USMF „Nicolae Testemiţanu”The article combines a listing of antifungal treatment therapies and some of the most practical modalities of their application in the treatment
of candidiasis, one of the most frequently encountered pathologies of the oral cavity mucosa. Individualized treatment according to the patient’s
specific condition and the appropriate use of the most effective remedies are especially important as many new and effective medicines have
been introduced in the past several years.Данная работа содержит краткую характеристику арсенала, которым располагает противогрибковая терапия, а также некоторые
практические возможности ее применения при одной из самых распространенных заболеваний полости рта – кандидоза. Успехи,
достигнутые в лечении кандидоза слизистой оболочки, во многом зависят от правильного выбора противогрибковых средств
по отношению к установленному диагнозу. Спецификация лечения, в зависимости от общего и локального статуса больного и
рационального использования выбранных препаратов, имеет большое значение, учитывая и тот факт, что в последнее время появились
новые высокоэффективные препараты
4U 1626-67 as seen by Suzaku before and after the 2008 torque reversal
Aims. The accretion-powered pulsar 4U 1626-67 experienced a new torque
reversal at the beginning of 2008, after about 18 years of steadily spinning
down. The main goal of the present work is to study this recent torque reversal
that occurred in 2008 February.
Methods. We present a spectral analysis of this source using two pointed
observations performed by Suzaku in 2006 March and in 2010 September.
Results. We confirm with Suzaku the presence of a strong emission-line
complex centered on 1 keV, with the strongest line being the hydrogen-like Ne
Ly-alpha at 1.025(3) keV. We were able to resolve this complex with up to seven
emission lines. A dramatic increase of the intensity of the Ne Ly-alpha line
after the 2008 torque reversal occurred, with the equivalent width of this line
reaching almost the same value measured by ASCA in 1993. We also report on the
detection of a cyclotron line feature centered at ~37 keV. In spite of the fact
that an increase of the X-ray luminosity (0.5-100 keV) of a factor of ~2.8
occurred between these two observations, no significant change in the energy of
the cyclotron line feature was observed. However, the intensity of the ~1 keV
line complex increased by an overall factor of ~8.
Conclusions. Our results favor a scenario in which the neutron star in 4U
1626-67 accretes material from a geometrically thin disk during both the
spin-up and spin-down phases.Comment: 7 pages, 5 figures and 2 tables. Accepted in A&
Autofluorescence lifetime augmented reality as a means for real-time robotic surgery guidance in human patients.
Due to loss of tactile feedback the assessment of tumor margins during robotic surgery is based only on visual inspection, which is neither significantly sensitive nor specific. Here we demonstrate time-resolved fluorescence spectroscopy (TRFS) as a novel technique to complement the visual inspection of oral cancers during transoral robotic surgery (TORS) in real-time and without the need for exogenous contrast agents. TRFS enables identification of cancerous tissue by its distinct autofluorescence signature that is associated with the alteration of tissue structure and biochemical profile. A prototype TRFS instrument was integrated synergistically with the da Vinci Surgical robot and the combined system was validated in swine and human patients. Label-free and real-time assessment and visualization of tissue biochemical features during robotic surgery procedure, as demonstrated here, not only has the potential to improve the intraoperative decision making during TORS but also other robotic procedures without modification of conventional clinical protocols
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