306 research outputs found
The maximum Number of parameters for the Hausman Test When the Estimators are from Different Sets of Equations
__Abstract__
Hausman (1978) developed a widely-used model specification test that has passed the test of time. The test is based on two estimators, one being consistent under the null hypothesis but inconsistent under the alternative, and the other being consistent under both the null and alternative hypotheses. In this paper, we show that the asymptotic variance of the difference of the two estimators can be a singular matrix. Moreover, in calculating the Hausman test there is a maximum number of parameters which is the number of different equations that are used to obtain the two estimators. Three illustrative examples are used, namely an exogeneity test for the linear regression model, a test for the Box-Cox transformation, and a test for sample selection bias
Method of refining 2,2-isopropylidenebis-3,5- dibromophenylene-4-oxydiethanol
A method of refining 2,2-isopropylidenebis-3,5-dibromophenylene-4-oxydiethanol is described which is characterized by recrystallization of 2,2-isopropylidenebis-3,5-dibromophenylene-4-oxydiethanol using one or more aromatic hydrocarbons such as benzene, xylene, toluene, ethylbenzene or pseudocumene
Constraints on chiral operators in N=2 SCFTs
Open Access, © The Authors. Article funded by SCOAP3.
This article is distributed under the terms of the Creative Commons
Attribution License (
CC-BY 4.0
), which permits any use, distribution and reproduction in
any medium, provided the original author(s) and source are credited
Super-A-polynomials for Twist Knots
We conjecture formulae of the colored superpolynomials for a class of twist
knots where p denotes the number of full twists. The validity of the
formulae is checked by applying differentials and taking special limits. Using
the formulae, we compute both the classical and quantum super-A-polynomial for
the twist knots with small values of p. The results support the categorified
versions of the generalized volume conjecture and the quantum volume
conjecture. Furthermore, we obtain the evidence that the Q-deformed
A-polynomials can be identified with the augmentation polynomials of knot
contact homology in the case of the twist knots.Comment: 22+16 pages, 16 tables and 5 figures; with a Maple program by Xinyu
Sun and a Mathematica notebook in the ancillary files linked on the right; v2
change in appendix B, typos corrected and references added; v3 change in
section 3.3; v4 corrections in Ooguri-Vafa polynomials and quantum
super-A-polynomials for 7_2 and 8_1 are adde
EFFECTS OF LOW-DOSE-GAMMA RAYS ON THE IMMUNE SYSTEM OF DIFFERENT ANIMAL MODELS OF DISEASE
We reviewed the beneficial or harmful effects of low-dose ionizing radiation on several diseases based on a search of the literature. The attenuation of autoimmune manifestations in animal disease models irradiated with low-dose γ-rays was previously reported by several research groups, whereas the exacerbation of allergic manifestations was described by others. Based on a detailed examination of the literature, we divided animal disease models into two groups: one group consisting of collagen-induced arthritis (CIA), experimental encephalomyelitis (EAE), and systemic lupus erythematosus, the pathologies of which were attenuated by low-dose irradiation, and another group consisting of atopic dermatitis, asthma, and Hashimoto’s thyroiditis, the pathologies of which were exacerbated by low-dose irradiation. The same biological indicators, such as cytokine levels and Tcell subpopulations, were examined in these studies. Low-dose irradiation reduced interferon (IFN)-gamma (γ) and interleukin (IL)-6 levels and increased IL-5 levels and the percentage of CD4+CD25+Foxp3+Treg cells in almost all immunological disease cases examined. Variations in these biological indicators were attributed to the attenuation or exacerbation of the disease’s manifestation. We concluded that autoimmune diseases caused by autoantibodies were attenuated by low-dose irradiation, whereas diseases caused by antibodies against external antigens, such as atopic dermatitis, were exacerbated
High incidence of silent myocardial ischemia in elderly patients with non insulin-dependent diabetes mellitus
Celem badania była ocena częstości występowania
niemego niedokrwienia mięśnia sercowego u bezobjawowych
chorych na cukrzycę w podeszłym wieku
(> 60 lat). Wstępnym etapem badania była maksymalna
próba wysiłkowa na bieżni ruchomej. Spośród
140 chorych u 54 (38,6%) nie udało się osiągnąć
diagnostycznego poziomu wysiłku podczas
próby lub nie można jej było wykonać z innych przyczyn,
u 39 z 86 chorych (45,3%) uzyskano pozytywny
wynik próby wysiłkowej. W drugim etapie tej pracy
u 93 chorych z dodatnią próbą wysiłkową, ale
u których nie można było uzyskać maksymalnego
wysiłku, wykonano scyntygrafię z użyciem talu w
teście z dipirydamolem. U 39 z 93 chorych (41,9%),
u których wystąpiły zaburzenia perfuzji, rozpoznano
nieme niedokrwienie mięśnia sercowego. U 18
chorych z niemym niedokrwieniem mięśnia sercowego,
którzy wyrazili zgodę, wykonano koronarografię.
U 17 spośród 18 chorych (94,4%) stwierdzono
znacznego stopnia zwężenia naczyń wieńcowych,
co potwierdziło duże znaczenie predykcyjne tej metody.
Podsumowując, stwierdzono, że częstość niemego niemego
niedokrwienia mięśnia sercowego u chorych
na cukrzycę typu 2 w podeszłym wieku jest bardzo
wysoka (26,3%). Te wyniki sugerują, że wczesna
intensywna diagnostyka zmian w naczyniach wieńcowych
może się okazać niezbędna jako uzupełnienie
rutynowego postępowania w tej grupie chorych.The present study was designed reveal the incidence
of silent myocardial ischemia in asymptomatic
elderly non-insulin-dependent diabetic (NIDDM) patients
(aged over 60 years). As a first step screening,
maximal treadmill exercise test was performed. Of
140 patients studied, 54 (38.6%) were unable or not
expected to achieve diagnostic levels of exercise
during treadmill testing. A positive exercise test was
noted in 39 of 86 (45.3%) subjects. As a second step
examination, dipyridamole thallium scintigraphy
was performed for 93 subjects who exhibited a positive
exercise test and could not perform a maximal
exercise test. Abnormal perfusion pattern was
found in 39 of 93 (41.9%), who were finally considered to have a silent myocardial ischemia. Coronary
angiography was performed in 18 subjects with
diagnosis of silent myocardial ischemia, who gave
their consent. Significant coronary artery stenosis
was in fact found in 17 of 18 (94.4%) subjects studied,
confirming a very high positive predictive value
of this diagnostic procedure. In conclusion, elderly
NIDDM patients (aged over 60 years) had an
extremely high prevalence (estimated 26.3%) of silent
myocardial ischemia. This evidence suggests that
early and intensive detection may be needed as
a part of routine care for this grou
Localization of N=4 Superconformal Field Theory on S^1 x S^3 and Index
We provide the geometrical meaning of the superconformal index.
With this interpretation, the superconformal index can be realized
as the partition function on a Scherk-Schwarz deformed background. We apply the
localization method in TQFT to compute the deformed partition function since
the deformed action can be written as a -exact form. The
critical points of the deformed action turn out to be the space of flat
connections which are, in fact, zero modes of the gauge field. The one-loop
evaluation over the space of flat connections reduces to the matrix integral by
which the superconformal index is expressed.Comment: 42+1 pages, 2 figures, JHEP style: v1.2.3 minor corrections, v4 major
revision, conclusions essentially unchanged, v5 published versio
Generalized Toda Theory from Six Dimensions and the Conifold
Recently, a physical derivation of the Alday-Gaiotto-Tachikawa correspondence
has been put forward. A crucial role is played by the complex Chern-Simons
theory arising in the 3d-3d correspondence, whose boundary modes lead to Toda
theory on a Riemann surface. We explore several features of this derivation and
subsequently argue that it can be extended to a generalization of the AGT
correspondence. The latter involves codimension two defects in six dimensions
that wrap the Riemann surface. We use a purely geometrical description of these
defects and find that the generalized AGT setup can be modeled in a pole region
using generalized conifolds. Furthermore, we argue that the ordinary conifold
clarifies several features of the derivation of the original AGT
correspondence.Comment: 27+2 pages, 3 figure
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