2,805 research outputs found
Generalized Rayleigh and Jacobi processes and exceptional orthogonal polynomials
We present four types of infinitely many exactly solvable Fokker-Planck
equations, which are related to the newly discovered exceptional orthogonal
polynomials. They represent the deformed versions of the Rayleigh process and
the Jacobi process.Comment: 17 pages, 4 figure
Metagenomes in the borderline ecosystems of the Antarctic cryptoendolithic communities
Antarctic cryptoendolithic communities are microbial ecosystems dwelling inside rocks of the Antarctic desert. We present the first 18 shotgun metagenomes from these communities to further characterize their composition, biodiversity, functionality, and adaptation. Future studies will integrate taxonomic and functional annotations to examine the pathways necessary for life to evolve in the extreme
Identification of Histopathological Criteria for the Diagnosis of Canine Cutaneous Progressive Angiomatosis
The term angiomatosis is used to denote a group of well-known to poorly characterized
proliferative vascular entities. In animals, cutaneous progressive angiomatosis (CPA) is a disorder
with variable prognosis related to the extension and depth of infiltration of the surrounding tissues
by vessels. CPA may share some microscopical features with other vascular proliferations such as
low-grade well-differentiated capillaritic hemangiosarcoma (HS), making the diagnosis not always
straightforward, especially in small biopsies. The aim of this study is to retrospectively assess the most
common diagnostic microscopical features of CPA in dogs. In this work, 11 histopathological criteria
were analyzed on 31 CPA and 11 primary cutaneous HS in dogs. Features significantly associated with
CPA included: lobular growth, interposition of connective tissue and adnexa between the vascular
proliferation, presence of nerve fibers, and a mixed vascular proliferative component. Absence of
plump/prominent endothelial cells, lack of atypia, and lack of mitoses were also significant factors
differentiating CPA from HS. Additional distinctive findings in CPA, although with no statistical
association to CPA diagnosis, were vascular shunting, absence of necrosis, and endothelial cell piling
up. In conclusion, the combined use of different microscopical clues allowed for the distinction of
CPA from HS and was considered useful for the diagnosis of CPA
The Left Ventricular Dysfunction Questionnaire: Italian translation and validation.
Patients affected by heart failure have a compromised quality of life (QOL) and in the last few years "health related quality of life" has become an important outcome indicator for the evaluation of heart failure treatment. Methods: Translation into Italian of the Left Ventricular Dysfunction Questionnaire (LVD-36), a new, 36-item, disease-specific health status instrument for patients with congestive heart failure, and its subsequent validation by administration to 50 consecutive patients in our heart failure outpatient clinic. The Italian LVD-36 was compared to the "The Minnesota Living with Heart Failure Questionnaire" (MLHF). Results: The Italian version of the LVD-36 correlates well with MLHF for ejection fraction (EF), NYHA class I and II, etiology and therapy. Since, however, the LVD-36 has only one domain, it may be able to offer more synthetic information than MLHF about patients' status. Conclusions: The Italian version of the LVD-36 appears to be a reliable instrument for assessing patients' QOL and the degree of limitations imposed on them by the disease. It is short, clear and easy to complete. In patients with heart failure the LVD-36 correlates well with the MLHF and may be considered a new disease- specific instrument to estimate changes in health status, and an useful support in optimizing therapeutic options
First-passage and first-exit times of a Bessel-like stochastic process
We study a stochastic process related to the Bessel and the Rayleigh
processes, with various applications in physics, chemistry, biology, economics,
finance and other fields. The stochastic differential equation is , where is the Wiener process. Due to the
singularity of the drift term for , different natures of boundary at
the origin arise depending on the real parameter : entrance, exit, and
regular. For each of them we calculate analytically and numerically the
probability density functions of first-passage times or first-exit times.
Nontrivial behaviour is observed in the case of a regular boundary.Comment: 15 pages, 6 figures, submitted to Physical Review
The Severe Heart Failure Questionnaire: Italian translation and linguistic validation
Introduction. The quality of life (QoL) is an important outcome indicator for heart failure management. As the use of a validate questionnaire in a different cultural context can affect data interpretation our main objective is the Italian translation and linguistic validation of the Severe Heart Failure Questionnaire (SHF) and its comparison with the MLHF (Minnesota Living with Heart Failure) Questionnaire.
Methods. The SHF and ?The Minnesota Living with Heart Failure Questionnaire? were translated. A consensus involving parallel back-translations was established among a group of cardiologists, psychologists and biostatisticians. SHF and MLHF were both administrated to a sample of 50 patients
Results. The patients? median age was 63 years. Ace inhibitors therapy was administered in 88% of cases and betablockers in 56% of cases. Finally the Italian version of SHF correlates well with MLHF for all domains, except life satisfaction SHF domain.
Discussion: The Italian version of the SHF correlates well with MLHF for almost all domains and it represents a valid alterna- tive for quality of life assessment in heart failure patients
General critical states in type-II superconductors
The magnetic flux dynamics of type-II superconductors within the critical
state regime is posed in a generalized framework, by using a variational theory
supported by well established physical principles. The equivalence between the
variational statement and more conventional treatments, based on the solution
of the differential Maxwell equations together with appropriate conductivity
laws is shown. Advantages of the variational method are emphasized, focusing on
its numerical performance, that allows to explore new physical scenarios. In
particular, we present the extension of the so-called double critical state
model to three dimensional configurations in which only flux transport
(T-states), cutting (C-states) or both mechanisms (CT-states) occur. The theory
is applied to several problems. First, we show the features of the transition
from T to CT states. Second, we give a generalized expression for the flux
cutting threshold in 3-D and show its relevance in the slab geometry. In
addition, several models that allow to treat flux depinning and cutting
mechanisms are compared. Finally, the longitudinal transport problem (current
is applied parallel to the external magnetic field) is analyzed both under T
and CT conditions. The complex interaction between shielding and transport is
solved.Comment: 21 figures, submitted for publicatio
The Diabetic Cardiomyopathy: The Contributing Pathophysiological Mechanisms
Individuals with diabetes mellitus (DM) disclose a higher incidence and a poorer prognosis of heart failure (HF) than non-diabetic people, even in the absence of other HF risk factors. The adverse impact of diabetes on HF likely reflects an underlying “diabetic cardiomyopathy” (DM–CMP), which may by exacerbated by left ventricular hypertrophy and coronary artery disease (CAD). The pathogenesis of DM-CMP has been a hot topic of research since its first description and is still under active investigation, as a complex interplay among multiple mechanisms may play a role at systemic, myocardial, and cellular/molecular levels. Among these, metabolic abnormalities such as lipotoxicity and glucotoxicity, mitochondrial damage and dysfunction, oxidative stress, abnormal calcium signaling, inflammation, epigenetic factors, and others. These disturbances predispose the diabetic heart to extracellular remodeling and hypertrophy, thus leading to left ventricular diastolic and systolic dysfunction. This Review aims to outline the major pathophysiological changes and the underlying mechanisms leading to myocardial remodeling and cardiac functional derangement in DM-CMP
Left ventricular (LV) pacing in newborns and infants. Echo assessment of LV systolic function and synchrony at 5-year follow-up
Background: Small retrospective studies reported that left ventricular (LV) pacing is likely to preserve LV function in children with isolated congenital complete atrioventricular block (CCAVB). The aim of this study was to prospectively evaluate LV contractility and synchrony in a cohort of neonates/infants at pacemaker implantation and follow-up. Methods: Patients with CCAVB who underwent LV pacing were evaluated with electrocardiogram and echocardiogram in a single-center, prospective study. Data were collected at implantation, at 1-month and every year of follow-up, up to 5 years. LV ventricular dimensions (diameters and volumes), systolic function (ejection fraction [EF] and global longitudinal strain [GLS]), and synchrony were evaluated. Data are reported as median (25th-75th centiles). Results: Twenty consecutive patients with CCAVB underwent pacemaker implantation (12 single-chamber pacemaker [VVIR] and eight dual-chamber pacemaker [DDD]) with epicardial leads: 17 on the LV apex and three on the free wall. Age at implantation was 0.3 months (1 day-4.5 months). Patients showed good clinical status, normal LV dimensions, preserved systolic function, and synchrony at 60 (30-60) months follow-up. EF increased to normal values in patients with preimplantation EF <50%. Presence of antibodies and pacing mode (DDD vs VVIR) had no impact on the outcome. Conclusions: LV pacing preserved LV systolic function and synchrony in neonates and infants with CCAVB at 5-year follow-up. LV EF improved in patients with low preimplantation EF. Pacing mode or the presence of autoantibodies did not demonstrated an impact on LV contractility and synchrony
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