658 research outputs found
Family businesses in Eastern European countries: How informal payments affect exports
This article investigates the effect of corruption on the export share of family firms in Eastern European countries. Using the Business Environment and Enterprise Performance Survey and panel data methods, we find that, in contrast to non-family firms, family firms are rather sensitive to corruption. In particular, the export share of family firms is positively associated with informal payments that aim to facilitate business operations. There are at least three compelling explanations for these results. First, if family firms are more risk averse than non-family firms, informal payments may represent additional export risk insurance. Second, informal payments may help family firms compensate for the lack of managerial capabilities to export. Finally, when institutional inefficiencies obstruct business, corruption may be a tool for family firms to protect their socioemotional wealth
Some homogenization and corrector results for nonlinear monotone operators
This paper deals with the limit behaviour of the solutions of quasi-linear
equations of the form \ \ds -\limfunc{div}\left(a\left(x, x/{\varepsilon
_h},Du_h\right)\right)=f_h on with Dirichlet boundary conditions.
The sequence tends to and the map is
periodic in , monotone in and satisfies suitable continuity
conditions. It is proved that weakly in , where is the solution of a homogenized problem \
-\limfunc{div}(b(x,Du))=f on . We also prove some corrector results,
i.e. we find such that in
Correctors for some nonlinear monotone operators
In this paper we study homogenization of quasi-linear partial differential
equations of the form -\mbox{div}\left( a\left( x,x/\varepsilon _h,Du_h\right)
\right) =f_h on with Dirichlet boundary conditions. Here the
sequence tends to as
and the map is periodic in monotone in
and satisfies suitable continuity conditions. We prove that
weakly in as where
is the solution of a homogenized problem of the form -\mbox{div}\left(
b\left( x,Du\right) \right) =f on We also derive an explicit
expression for the homogenized operator and prove some corrector results,
i.e. we find such that in
Psychometric properties and diagnostic accuracy of the short form of the geriatric anxiety scale (GAS-10)
Background: Anxious symptoms have a negative impact on different aspects of the elderly\u2019s quality of life, ranging from the adoption of unhealthy lifestyle behaviours to an increased functional impairment and a greater physical disability. Different brief assessment instruments have been developed as efficacy measures of geriatric anxiety in order to overcome psychometric weaknesses of its long form. Among these, the 10-item Geriatric Anxiety Scale (GAS-10) showed strong psychometric properties in community-dwelling samples. However, its diagnostic accuracy is still unexplored, as well as its discriminative power in clinical samples. Methods: In the present study, we explored the psychometric performance of the GAS-10 in the elderly through Item Response Theory in a sample of 1200 Italian community-dwelling middle-aged and elderly adults (53.8% males, mean age = 65.21 \ub1 9.19 years). Concurrent validity, as well as diagnostic accuracy, was examined in a non-clinical sample (N = 229; 46.72% males) and clinical sample composed of 35 elderly outpatients (74.28% females) with Generalized Anxiety Disorder (GAD). Results: The GAS-10 displayed good internal construct validity, with unidimensional structure and no local dependency, good accuracy, and no signs of Differential Item Functioning (DIF) or measurement bias due to gender, but negligible due to the age. Differences in concurrent validity and diagnostic accuracy among the long form version of the GAS and the GAS-10 were not found significant. The GAS-10 may be more useful than the longer versions in many clinical and research applications, when time constraints or fatigue are issues. Conclusion: Using the ROC curve, the GAS-10 showed good discriminant validity in categorizing outpatients with GAD disorder, and high anxiety symptoms as measured by the GAS-SF cut-off. The stable cut-off point provided could enhance the clinical usefulness of the GAS-10, which seems to be a promising valid and reliable tool for maximize diagnostic accuracy of geriatric anxiety symptoms
Local and global behaviour of nonlinear equations with natural growth terms
This paper concerns a study of the pointwise behaviour of positive solutions
to certain quasi-linear elliptic equations with natural growth terms, under
minimal regularity assumptions on the underlying coefficients. Our primary
results consist of optimal pointwise estimates for positive solutions of such
equations in terms of two local Wolff's potentials.Comment: In memory of Professor Nigel Kalto
Hole conductivity in oxygen-excess BaTi(1-x)CaxO(3-x+d)
BaTiO3 containing Ca substituted for Ti as an acceptor dopant, with oxygen vacancies for charge compensation
and processed in air, is a p-type semiconductor. The hole conductivity is attributed to uptake of a small
amount of oxygen which ionises by means of electron transfer from lattice oxide ions, generating O�
ions as the source of p-type semiconductivity. Samples heated in high pressure O2, up to 80 atm, absorb
up to twice the amount expected from the oxygen vacancy concentration. This is attributed to
incorporation of superoxide, O2
�, ions in oxygen vacancies associated with the Ca2+ dopant and is
supported by Raman spectroscopy results
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Cancer burden among HIV-positive persons in Nigeria: preliminary findings from the Nigerian AIDS-cancer match study
Background: Although Nigeria has a large HIV epidemic, the impact of HIV on cancer in Nigerians is unknown. Methods: We conducted a registry linkage study using a probabilistic matching algorithm among a cohort of HIV positive persons registered at health facilities where the Institute of Human Virology Nigeria (IHVN) provides HIV prevention and treatment services. Their data was linked to data from 2009 to 2012 in the Abuja Cancer Registry. Match compatible files with first name, last name, sex, date of birth and unique HIV cohort identification numbers were provided by each registry and used for the linkage analysis. We describe demographic characteristics of the HIV clients and compute Standardized Incidence Ratios (SIRs) to evaluate the association of various cancers with HIV infection. Results: Between 2005 and 2012, 17,826 persons living with HIV (PLWA) were registered at IHVN. Their median age (Interquartile range (IQR)) was 33 (27–40) years; 41% (7246/17826) were men and 59% (10580/17826) were women. From 2009 to 2012, 2,029 clients with invasive cancers were registered at the Abuja Cancer Registry. The median age (IQR) of the cancer clients was 45 (35–68) years. Among PLWA, 39 cancer cases were identified, 69% (27/39) were incident cancers and 31% (12/39) were prevalent cancers. The SIR (95% CI) for the AIDS Defining Cancers were 5.7 (4.1, 7.2) and 2.0 (0.4, 3.5), for Kaposi Sarcoma and Cervical Cancer respectively. Conclusion: The risk of Kaposi Sarcoma but not Cervical Cancer or Non-Hodgkin’s Lymphoma, was significantly increased among HIV positive persons, compared to the general population in Nigeria
On the commutability of homogenization and linearization in finite elasticity
We study non-convex elastic energy functionals associated to (spatially)
periodic, frame indifferent energy densities with a single non-degenerate
energy well at SO(n). Under the assumption that the energy density admits a
quadratic Taylor expansion at identity, we prove that the Gamma-limits
associated to homogenization and linearization commute. Moreover, we show that
the homogenized energy density, which is determined by a multi-cell
homogenization formula, has a quadratic Taylor expansion with a quadratic term
that is given by the homogenization of the quadratic term associated to the
linearization of the initial energy density
Diffeomorphism-invariant properties for quasi-linear elliptic operators
For quasi-linear elliptic equations we detect relevant properties which
remain invariant under the action of a suitable class of diffeomorphisms. This
yields a connection between existence theories for equations with degenerate
and non-degenerate coerciveness.Comment: 16 page
Derivation of a linearised elasticity model from singularly perturbed multiwell energy functionals
Linear elasticity can be rigorously derived from finite elasticity under the assumption of small loadings in terms of Gamma-convergence. This was first done in the case of one-well energies with super-quadratic growth and later generalised to different settings, in particular to the case of multi-well energies where the distance between the wells is very small (comparable to the size of the load). In this paper we study the case when the distance between the wells is independent of the size of the load. In this context linear elasticity can be derived by adding to the multi-well energy a singular higher order term which penalises jumps from one well to another. The size of the singular term has to satisfy certain scaling assumptions whose optimality is shown in most of the cases. Finally, the derivation of linear elasticty from a two-well discrete model is provided, showing that the role of the singular perturbation term is played in this setting by interactions beyond nearest neighbours
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