1,203 research outputs found
An improved geometric inequality via vanishing moments, with applications to singular Liouville equations
We consider a class of singular Liouville equations on compact surfaces
motivated by the study of Electroweak and Self-Dual Chern-Simons theories, the
Gaussian curvature prescription with conical singularities and Onsager's
description of turbulence. We analyse the problem of existence variationally,
and show how the angular distribution of the conformal volume near the
singularities may lead to improvements in the Moser-Trudinger inequality, and
in turn to lower bounds on the Euler-Lagrange functional. We then discuss
existence and non-existence results.Comment: some references adde
New improved Moser-Trudinger inequalities and singular Liouville equations on compact surfaces
We consider a singular Liouville equation on a compact surface, arising from
the study of Chern-Simons vortices in a self dual regime. Using new improved
versions of the Moser-Trudinger inequalities (whose main feature is to be
scaling invariant) and a variational scheme, we prove new existence results.Comment: to appear in GAF
LANDSAT-4/5 image data quality analysis
A LANDSAT Thematic Mapper (TM) quality evaluation study was conducted to identify geometric and radiometric sensor errors in the post-launch environment. The study began with the launch of LANDSAT-4. Several error conditions were found, including band-to-band misregistration and detector-to detector radiometric calibration errors. Similar analysis was made for the LANDSAT-5 Thematic Mapper and compared with results for LANDSAT-4. Remaining band-to-band misregistration was found to be within tolerances and detector-to-detector calibration errors were not severe. More coherent noise signals were observed in TM-5 than in TM-4, although the amplitude was generally less. The scan direction differences observed in TM-4 were still evident in TM-5. The largest effect was in Band 4 where nearly a one digital count difference was observed. Resolution estimation was carried out using roads in TM-5 for the primary focal plane bands rather than field edges as in TM-4. Estimates using roads gave better resolution. Thermal IR band calibration studies were conducted and new nonlinear calibration procedures were defined for TM-5. The overall conclusion is that there are no first order errors in TM-5 and any remaining problems are second or third order
Semilinear equations with exponential nonlinearity and measure data
We study the existence and non-existence of solutions of the problem [GRAPHICS] where Omega is a bounded domain in R-N, N >=, 3, and it is a Radon measure. We prove that if it 4 pi HN-2, then (0.1) has a unique solution. We also show that the constant 4 pi in this condition cannot be improved. (c) 2005 Elsevier SAS. All rights reserved
Existence of Multistring Solutions of the Self-Gravitating Massive Boson
We consider a semilinear elliptic system which include the model system of
the strings in the cosmology as a special case. We prove existence of
multi-string solutions and obtain precise asymptotic decay estimates near
infinity for the solutions.
As a special case of this result we solve an open problem posed in
\cite{yan}Comment: 12 page
Classification and nondegeneracy of Toda system with singular sources
We consider the following Toda system \Delta u_i + \D \sum_{j = 1}^n
a_{ij}e^{u_j} = 4\pi\gamma_{i}\delta_{0} \text{in}\mathbb R^2, \int_{\mathbb
R^2}e^{u_i} dx -1\delta_0a_{ij}\gamma_i=0\forall \;1\leq i\leq n\gamma_i+\gamma_{i+1}+...+\gamma_j \notin \mathbb Z1\leq i\leq
j\leq nu_i$ is \textit{radially symmetric} w.r.t. 0.
(iii) We prove that the linearized equation at any solution is
\textit{non-degenerate}. These are fundamental results in order to understand
the bubbling behavior of the Toda system.Comment: 28 page
Conserving plant diversity in Europe: outcomes, criticisms and perspectives of the Habitats Directive application in Italy
Habitat Directive is the core strategy of nature conservation in Europe aiming at halting biodiversity loss. In this study the results of the third Italian assessment regarding the conservation status (CS) of plants listed in the Habitat Directive (Flora of community interest—FCI) was presented. Data was collected from several sources related to plant distribution, population data, habitats and pressures. Following the official European procedure, all parameters were evaluated and combined to give the CS of each taxon in each biogeographical region of presence. A comparison between the recent Italian IUCN and Reporting assessments was performed in order to evaluate the consistency between these two assessments. The official EU checklist comprises 113 Italian plant taxa, 107 of which were examined in this study. Our results showed a critical situation with only 34% of favourable CS, while 50% were unfavourable (40% inadequate plus 10% bad) and 16% unknown, in particular in the Mediterranean bioregion, where the unfavourable assessments reach the 65%. The results of the Report were consistent with those of the IUCN assessment, in which 41.9% of plants were threatened with extinction. This report highlighted some benefits and criticisms at national level, but it may have a wider significance. Although a general advance of knowledge, a great effort is needed to reach the Habitats Directive goals. Despite the limited resources, monitoring activities needs to be improved in order to close information gaps for several plants. A positive outcome was the development of a specific national project funded by the Italian Ministry of Environment, with the ambitious target to set future monitoring activities for FCI and optimize monitoring efforts
RF MEMS ohmic switches for matrix configurations
Two different topologies of radio frequency micro-electro-mechanical system (RF MEMS) series ohmic switches (cantilever and clamped–clamped beams) in coplanar waveguide (CPW) configuration have been characterized by means of DC, environmental, and RF measurements. In particular, on-wafer checks have been followed by RF test after vibration, thermal shocks, and temperature cycles. The devices have been manufactured on high resistivity silicon substrates, as building blocks to be implemented in different single-pole 4-throw (SP4 T), double-pole double-throw (DPDT) configurations, and then integrated in Low Temperature Co-fired Ceramics (LTCC) technology for the realization of large-order Clos 3D networks
Hospital Organization and Importance of an Interventional Radiology Inpatient Admitting Service:Italian Single-Center 3-year Experience
In June 2005 a Complex Operating Unit of
Interventional Radiology (COUIR), consisting of an outpatient
visit service, an inpatient admitting service with
four beds, and a day-hospital service with four beds was
installed at our department. Between June 2005 and May
2008, 1772 and 861 well-screened elective patients were
admitted to the inpatient ward of the COUIR and to the
Internal Medicine Unit (IMU) or Surgery Unit (SU) of our
hospital, respectively, and treated with IR procedures. For
elective patients admitted to the COUIR’s inpatient ward,
hospital stays were significantly shorter and differences
between reimbursements and costs were significantly
higher for almost all IR procedures compared to those for
patients admitted to the IMU and SU (Student’s t-test for
unpaired data, p\0.05). The results of the 3-year activity
show that the activation of a COUIR with an inpatient
admitting service, and the better organization of the patient
pathway that came with it, evidenced more efficient use of
resources, with the possibility for the hospital to save
money and obtain positive margins (differences between
reimbursements and costs). During 3 years of activity, the
inpatient admitting service of our COUIR yielded a positive
difference between reimbursements and effective costs
of €1,009,095.35. The creation of an inpatient IR service
and the admission of well-screened elective patients
allowed short hospitalization times, reduction of waiting
lists, and a positive economic outcome.
Keywords Inpatients Hospitalization Costs
Reimbursement
Primary-school class composition and the development of social capital
We study the development of social capital through adult civic engagement, in relation to social capital exposure having occurred during childhood based on experiences outside the family at primary school. We assume that the types of classmates in attendance at a child's school would have influenced her/his social capital. To identify the types of classmates, we take advantage of the heterogeneity in the ability levels of British primary-school classes during the 1960s. At that time, some schools were practicing a method of streaming, whereas others were not. Using British National Child Development data, we construct a single score of civic engagement and evaluate the effect on adult civic engagement of attending homogeneous-ability classes versus nonhomogeneous-ability classes and being in high-, average- or low-ability classes when enrolled in streamed schools. Our results show that children who were grouped in homogeneous-ability classes developed a lower interest in civic engagement than their peers who attended mixed-ability classes (nonstreamed schools). Moreover, among children who attended streamed schools, a lower attitude toward civic engagement was observed among low-ability students. Thus, streaming appears to be detrimental to social capital development, especially for low-ability individuals
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