New degeneration of Fay's identity and its application to integrable systems

In this paper we prove a new degenerated version of Fay's trisecant identity. The new identity is applied to construct new algebro-geometric solutions of the multi-component nonlinear Schr\"odinger equation. This approach also provides an independent derivation of known algebro-geometric solutions to the Davey-Stewartson equations

On the numerical evaluation of algebro-geometric solutions to integrable equations

Physically meaningful periodic solutions to certain integrable partial differential equations are given in terms of multi-dimensional theta functions associated to real Riemann surfaces. Typical analytical problems in the numerical evaluation of these solutions are studied. In the case of hyperelliptic surfaces efficient algorithms exist even for almost degenerate surfaces. This allows the numerical study of solitonic limits. For general real Riemann surfaces, the choice of a homology basis adapted to the anti-holomorphic involution is important for a convenient formulation of the solutions and smoothness conditions. Since existing algorithms for algebraic curves produce a homology basis not related to automorphisms of the curve, we study symplectic transformations to an adapted basis and give explicit formulae for M-curves. As examples we discuss solutions of the Davey-Stewartson and the multi-component nonlinear Schr\"odinger equations.Comment: 29 pages, 20 figure

Prevalence and effect of parasitic infections on cycling in traditionally managed cattle herds in Bauchi, Nigeria

The incidence of infection and infestation by parasites (i.e. helminth, ectoparasites and haemoparasites) and the relationship between them and cycling in cattle was investigated in 16 traditionally managed herds in Bauchi, Nigeria. Parasitic infection and infestation show seasonality with most infections and infestations occurring in the rainy season. This study also shows some relationship between parasitic infection and infestation with cycling in some poorly managed herds. Good management practices were also shown to be important in disease control and prevention

Sobre operadores de integración fraccional y algoritmos computacionales

Algunos autores como Kalla, Saxena y Saigo, han definido y estudiado operadores de integración fraccional que tienen como núcleo la función hipergeométrica de Gauss. El propósito de este trabajo es estudiar tales operadores con la función R-∝(b1,b2;t,X) de Carlson como núcleo, así como también presentar algoritmos para el cálculo de semidiferintegrales.Kalla, Saxena, Saigo and some other authors, have defined and studied fractional operators with the Gauss hypergeometric function as nucleus. The object of this paper is to study operators containing the Carlson's function R-∝(b1,b2;t,X); as well as to present and discuss algorithms for numerical calculations of semidiferintegrals

Structural Progression in Patients with Definite and Non-Definite Arrhythmogenic Right Ventricular Cardiomyopathy and Risk of Major Adverse Cardiac Events

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited disease characterised by early arrhythmias and structural changes. Still, there are limited echocardiography data on its structural progression. We studied structural progression and its impact on the occurrence of major adverse cardiovascular events (MACE). In this single-centre observational cohort study, structural progression was defined as the development of new major or minor imaging 2010 Task Force Criteria during follow-up. Of 101 patients, a definite diagnosis of ARVC was made in 51 patients, while non-definite ‘early’ disease was diagnosed in 50 patients. During 4 years of follow-up (IQR: 2–6), 23 (45%) patients with a definite diagnosis developed structural progression while only 1 patient in the non-definite (early) group gained minor imaging Task Force Criteria. Male gender was strongly associated with structural progression (62% of males progressed structurally, while 88% of females remained stable). Patients with structural progression were at higher risk of MACE (64% of patients with MACE had structural progression). Therefore, the rate of structural progression is an essential factor to be considered in ARVC studies

Do monosymptomatic stroke patients with dizziness present a vestibular syndrome without nystagmus? An underestimated entity.

BACKGROUND AND PURPOSE Vestibular symptoms are common in emergency department (ED) patients and have various causes, including stroke. Accurate identification of stroke in patients with vestibular symptoms is crucial for timely management. We conducted a prospective cross-sectional study from 2015 to 2019 to determine stroke prevalence and associated symptoms in ED patients with vestibular symptoms, aiming to improve diagnosis and outcomes. METHODS As part of the DETECT project, we screened 1647 ED patients with acute vestibular symptoms. Following a retrospective analysis of 961 head and neck magnetic resonance imaging (MRI) scans, we included 122 confirmed stroke cases and assessed them for vestibular signs and symptoms. RESULTS Stroke prevalence in dizzy patients was 13% (122/961 MRI scans). Most patients (95%) presented with acute vestibular symptoms with or without nystagmus, whereas 5% had episodic vestibular syndrome (EVS). Nystagmus was present in 50% of stroke patients. Eighty percent had a purely posterior circulation stroke, and nystagmus was absent in 46% of these patients. Seven patients (6%) had lesions in both the anterior and posterior circulation. Vertigo was experienced by 52% regardless of territory. CONCLUSIONS A stroke was identified in 13% of ED patients presenting with acute vestibular symptoms. In 5%, it was EVS. Most strokes were in the posterior circulation territory; vertigo occurred with similar frequency in anterior and posterior circulation stroke, and absence of nystagmus was common in both

Investigating short-time-scale variations in cometary ions around comet 67P

The highly varying plasma environment around comet 67P/Churyumov–Gerasimenko inspired an upgrade of the ion mass spectrometer (Rosetta Plasma Consortium Ion Composition Analyzer) with new operation modes, to enable high time resolution measurements of cometary ions. Two modes were implemented, one having a 4 s time resolution in the energy range 0.3–82 eV/q and the other featuring a 1 s time resolution in the energy range 13–50 eV/q. Comparing measurements made with the two modes, it was concluded that 4 s time resolution is enough to capture most of the fast changes of the cometary ion environment. The 1462 h of observations done with the 4 s mode were divided into hour-long sequences. It is possible to sort 84 per cent of these sequences into one of five categories, depending on their appearance in an energy–time spectrogram. The ion environment is generally highly dynamic, and variations in ion fluxes and energies are seen on time-scales of 10 s to several minutes

Stroke Prediction Based on the Spontaneous Nystagmus Suppression Test in Dizzy Patients: A Diagnostic Accuracy Study.

ObjectiveFailure of fixation suppression of spontaneous nystagmus is sometimes seen in patients with vestibular strokes involving the cerebellum or brainstem, however, the accuracy of this test for the discrimination between peripheral and central causes in patients with an acute vestibular syndrome (AVS) is unknown.MethodsPatients with AVS were screened and recruited (convenience sample) as part of a prospective cross-sectional study in the Emergency Department between 2015-2020. All patients received neuroimaging which served as a reference standard. We recorded fixation suppression with video-oculography (VOG) for straight, right and left gaze. The ocular fixation index (OFI) and the spontaneous nystagmus slow velocity reduction was calculated.ResultsWe screened 1646 dizzy patients in the emergency department and tested for spontaneous nystagmus in 148 included AVS patients. We analyzed 56 patients with a diagnosed acute unilateral vestibulopathy (vestibular neuritis) and 28 patients with a confirmed stroke. There was a complete nystagmus fixation suppression in 49.5% of AVS patients, in 40% of patients with vestibular neuritis and in 62.5% of vestibular strokes. OFI scores had no predictive value for detecting strokes, however, a nystagmus reduction of less than 2deg/s showed a high accuracy of 76.9% (CI 0.59-0.89) with a sensitivity of 62.2% and specificity of 84.8% in detecting strokes..ConclusionsThe presence of fixation suppression does not rule out a central lesion. The magnitude of suppression was lower compared to patients with vestibular neuritis. The nystagmus suppression test still predicts accurately vestibular strokes provided that eye movements are recorded with VOG.Classification of EvidenceThis study provides Class II evidence that in patients with an acute vestibular syndrome, decreased fixation suppression recorded with VOG occurred more often in stroke (76.9%) than in vestibular neuritis (37.8%)

Discrimination, Crypticity, and Incipient Taxa in Entamoeba

Persistent difficulties in resolving clear lineages in diverging populations of prokaryotes or unicellular eukaryotes (protistan polyphyletic groups) are challenging the classical species concept. Although multiple integrated approaches would render holistic taxonomies, most phylogenetic studies are still based on single-gene or morphological traits. Such methodologies conceal natural lineages, which are considered “cryptic.” The concept of species is considered artificial and inadequate to define natural populations. Social organisms display differential behaviors toward kin than to nonrelated individuals. In “social” microbes, kin discrimination has been used to help resolve crypticity. Aggregative behavior could be explored in a nonsocial protist to define phylogenetic varieties that are considered “cryptic.” Two Entamoeba invadens strains, IP-1 and VK-1:NS are considered close populations of the same “species.” This study demonstrates that IP-1 and VK-1:NS trophozoites aggregate only with alike members and discriminate members of different strains based on behavioral and chemical signals. Combined morphological, behavioral/chemical, and ecological studies could improve Archamoebae phylogenies and define cryptic varieties. Evolutionary processes in which selection acted continuously and cumulatively on ancestors of Entamoeba populations gave rise to chemical and behavioral signals that allowed individuals to discriminate nonpopulation members and, gradually, to the emergence of new lineages; alternative views that claim a “Designer” or “Creator” as responsible for protistan diversity are unfounded