5,533 research outputs found
Electron Wavefunctions and Densities for Atoms
With a special `Ansatz' we analyse the regularity properties of atomic
electron wavefunctions and electron densities. In particular we prove an a
priori estimate, and obtain for the spherically averaged electron density,
, that exists and is non-negative
Non-isotropic cusp conditions and regularity of the electron density of molecules at the nuclei
We investigate regularity properties of molecular one-electron densities rho
near the nuclei. In particular we derive a representation rho(x)=mu(x)*(e^F(x))
with an explicit function F, only depending on the nuclear charges and the
positions of the nuclei, such that mu belongs to C^{1,1}(R^3), i.e., mu has
locally essentially bounded second derivatives. An example constructed using
Hydrogenic eigenfunctions shows that this regularity result is sharp. For
atomic eigenfunctions which are either even or odd with respect to inversion in
the origin, we prove that mu is even C^{2,\alpha}(R^3) for all alpha in (0,1).
Placing one nucleus at the origin we study rho in polar coordinates x=r*omega
and investigate rho'(r,omega) and rho''(r,omega) for fixed omega as r tends to
zero. We prove non-isotropic cusp conditions of first and second order, which
generalize Kato's classical result.Comment: 19 page
Positivity and lower bounds to the decay of the atomic one-electron density
We investigate properties of the spherically averaged atomic one-electron
density rho~(r). For a rho~ which stems from a physical ground state we prove
that rho~ > 0. We also give exponentially decreasing lower bounds to rho~ in
the case when the eigenvalue is below the corresponding essential spectrum.Comment: 20 page
Probing Compositeness with Higgs Boson Decays at the LHC
A method is proposed to directly probe the Higgs boson compositeness using
the unique characteristics of a boosted Higgs boson produced in association
with a weak gauge boson (). The discovery potential for the upcoming
LHC running is presented, showing that compositeness scales up to 3 TeV can be
probed at the LHC with an integrated luminosity of fb
collected at TeV.Comment: 7 pages, 8 figure
Diatom assemblages in Portuguese temporary rivers
During a survey of benthic diatoms in watercourses from Portugal in spring and summer 2006 and 2007, 76 sites in temporary streams (according to the National Water Institute classification) have been studied. These streams belong to the Ribeiras do Algarve (10 sites), Guadiana (19 sites), Mira (7 sites), Sado (16 sites), Tejo (20 sites), and Douro (4 sites) watersheds. Among these 76 sites, the National Water Institute classified only 48 as reference sites, and only these were therefore considered in the statistical analysis performed.
A total of 276 diatom taxa have been identified in the 48 reference sites, from which 112 were present in abundance above 2% in at least one inventory. The most frequent taxa, present in more than 50% of the studied sites, were Achnanthidium minutissimum (KĂźtzing) Czarnecki, Amphora pediculus (KĂźtzing) Grunow, Cocconeis euglypta Ehrenberg, Eolimna minima (Grunow) Lange-Bertalot, Gomphonema parvulum KĂźtzing, G. rosenstockianum Lange-Bertalot & E. Reichardt, Navicula gregaria Donkin, N. veneta KĂźtzing, Nitzschia inconspicua Grunow and Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot. These are neutrophilous to alcaliphilous, mesosaprobous to -meso-saprobous, eutraphentic to indifferent taxa.
Furthermore, a multivariate analysis relating diatom assemblages with environmental parameters is presented and the ecological preferences of not yet well known taxa, such as G. rosenstockianum, are provided
Perceived parenting and social support: can they predict academic achievement in Argentinean college students?
The aim of this study was to test the ability to predict academic achievement through the perception of parenting and social support in a sample of 354 Argentinean college students. Their mean age was 23.50 years (standard deviation =2.62 years) and most of them (83.3%) were females. As a prerequisite for admission to college, students are required to pass a series of mandatory core classes and are expected to complete them in two semesters. Delay in completing the curriculum is considered low academic achievement. Parenting was assessed taking into account the mother and the father and considering two dimensions: responsiveness and demandingness. Perceived social support was analyzed considering four sources: parents, teachers, classmates, and best friend or boyfriend/girlfriend. Path analysis showed that, as hypothesized, responsiveness had a positive indirect effect on the perception of social support and enhanced achievement. Demandingness had a different effect in the case of the mother as compared to the father. In the mother model, demandingness had a positive direct effect on achievement. In the case of the father, however, the effect of demandingness had a negative and indirect impact on the perception of social support. Teachers were the only source of perceived social support that significantly predicted achievement. The pathway that belongs to teachers as a source of support was positive and direct. Implications for possible interventions are discussed.Fil: de la Iglesia, Guadalupe. Universidad de Buenos Aires. Facultad de PsicologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas; ArgentinaFil: Freiberg Hoffmann, AgustĂn. Universidad de Buenos Aires. Facultad de PsicologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas; ArgentinaFil: Fernandez Liporace, Maria Mercedes. Universidad de Buenos Aires. Facultad de PsicologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas; Argentin
Pollensaisondefinitionen im Kontext der saisonalen polleninduzierten allergischen Rhinitis in sßdeuropäischen Ländern
The identification of the causative pollen in polysensitized patients with seasonal allergic rhinitis (SAR) is of particular challenge to healthcare professionals. As this diagnostic step is essential for the prescription of allergen-specific immunotherapy (AIT), the only disease-modifying treatment of SAR, a clinical decision support system (CDSS) was designed in the @IT.2020 multicenter study to assist professionals with this task. The diagnostic decision process is complicated by overlapping pollination periods, which are particularly prominent in regions with Mediterranean climate such as Southern Europe. A position paper by the European Academy of Allergy and Clinical Immunology (EAACI) suggests criteria to define pollen seasons for medical purposes, especially for standardized monitoring of symptomatic patients in clinical trials testing AIT.
OBJECTIVE:
This present thesis aims to test definitions of pollen seasons proposed by EAACI in four Mediterranean countries for seven pollen taxa.
METHODS:
From January 1 to December 31, 2018, pollen data was collected daily in six cities (namely Valencia, Marseille, Rome, Messina, Istanbul and Izmir) for Poaceae, Oleaceae, Fagales, Cupressaceae, Urticaceae (Parietaria spp.) and Compositae (Ambrosia spp., Artemisia spp.) as part of the @IT.2020 multicenter study. EAACI criteria were applied to the collected data and pollen seasons were identified. On the basis of these seasonal definitions, a potential unified monitoring period for patients sensitized to Urticaceae, Poaceae and Cupressaceae in AIT trials was determined.
RESULTS
The analysis revealed a wide variance in the patterns and lengths of the investigated pollen seasons, both within and between countries. By adding a stop signal according to the EAACI criteria and, consequently, excluding periods of lower pollen concentration (i.e., intercurrent periods), a fragmentation of the seasons was observed. A fragmentation into eight and twelve segments was found for the fragmented pollen seasons and the fragmented high seasons, respectively. Potential monitoring periods for AIT trials included up to 341 days with low pollen exposure (i.e., below EAACI thresholds). The removal of intercurrent periods with no or low pollen counts (i.e., by the fragmented pollen season method) improved the precision of EAACI criteria.
CONCLUSION
Potential symptom-monitoring periods based on EAACI criteria include intermittent periods with low pollen concentrations. This is particularly problematic regarding the assessment of AIT effectiveness as it is based on the evaluation of that patientsâ symptoms within the defined pollen exposure periods. To improve the precision of exposure-related outcomes, fragmented pollen seasons based on EAACI criteria are recommended for Southern Europe. This approach should be further investigated.Bei poly-sensibilisierten Patienten mit pollen-induzierter allergischer Rhinitis stehen Mediziner vor der diagnostischen Herausforderung, das klinisch relevante Hauptallergen zu identifizieren, um eine adäquate allergenspezifische Immuntherapie (AIT) einzuleiten. Insbesondere in mediterranen Ländern erschweren uĚberlappende Pollenflugzeiten und Kreuzsensibilisierungen die Diagnostik. In diesem Kontext wurde ein klinisches EntscheidungsunterstuĚtzungssystem (CDSS) entwickelt, dessen Einzelkomponenten im Rahmen der multizentrischen @IT.2020 Studie untersucht wurden. Ein Positionspapier der European Academy of Allergy and Clinical Immunology (EAACI) schlägt Kriterien fuĚr Pollensaisondefinitionen vor, insbesondere fuĚr die standardisierte Ăberwachung von symptomatischen Patienten in klinischen AIT-Studien.
ZIELSETZUNG:
Das Ziel dieser Arbeit ist die Untersuchung der im EAACI Positionspapier empfohlenen Pollensaisondefinitionen in vier Ländern SuĚdeuropas fuĚr sieben Pollenarten.
METHODIK: Im Rahmen der @IT.2020 Studie wurden in sechs Städten (Valencia, Marseille, Rom, Messina, Istanbul, Izmir) vom 1. Januar bis 31. Dezember 2018 tägliche Pollenkonzentrationen fuĚr Poaceae, Oleaceae, Fagales, Cupressaceae, Urticaceae (Parietaria spp.) und Compositae (Ambrosia spp., Artemisia spp.) erhoben. Basierend auf diesen Daten wurden die jeweiligen Pollensaisons nach EAACI-Kriterien identifiziert. FuĚr Urticaceae, Poaceae und Cupressaceae wurde ein potenzieller einheitlicher Ăberwachungszeitraum fuĚr Patienten in AIT-Studien erstellt.
ERGEBNISSE:
Die Untersuchung ergab eine ausgeprägte Heterogenität hinsichtlich Muster und Länge der untersuchten Pollensaisons, sowohl zwischen als auch innerhalb der Länder. Durch HinzufuĚgen eines auf EAACI-Kriterien basierenden Stoppsignals, wurden Perioden mit geringerer Pollenkonzentration (âZwischenperiodenâ) ausgeschlossen. Daraus resultierte eine Fragmentierung in maximal 8 Segmente fuĚr die Gesamt-Pollensaison und in maximal 12 Segmente fuĚr die Hochsaison. Potenzielle Ăberwachungszeiträume fuĚr AIT-Studien umfassten bis zu 341 Tage mit geringer Pollenbelastung (unterhalb der EAACI-Grenzwerte). Der Ausschluss von âZwischenperioden" (âFragmentierte Pollensaison"-Methode) verbessert die Genauigkeit der EAACI-Kriterien.
SCHLUSSFOLGERUNG:
Auf Anwendung der EAACI-Kriterien basierende SymptomuĚberwachungszeiträume in AIT Studien beinhalten teils lange Zeiträume mit niedrigen Pollenkonzentrationen. Dies ist insbesondere mit Blick auf die Beurteilung von Therapieerfolgen und Studien-Outcomes problematisch, denn diese basieren häufig auf der Symptombewertung innerhalb festgelegter Expositionszeiträume. Um eine mĂśgliche Verzerrung zu minimieren, wird die Verwendung fragmentierter, auf EAACI-Kriterien basierender, Pollensaisons fuĚr SuĚdeuropa empfohlen. Dieser Ansatz sollte in weiteren Studien untersucht werden
The electron density is smooth away from the nuclei
We prove that the electron densities of electronic eigenfunctions of atoms
and molecules are smooth away from the nuclei.Comment: 16 page
âStreamedâ voices : Facebook posts and related thoughts on mainstreaming and inclusion
Several studies conducted in the recent past reveal that a large number of Hungarian mainstream teachers say they are unable and unprepared to deal with disabled students in the classroom. This paper aims to examine what the reasons for the above situation might be. In order to gain deeper insight into teachersâ uncertainty, we listen to studentsâ voices. As insider researchers, having visual impairments ourselves, we also take a look into the present outcomes of an ongoing research where we examine visually impaired secondary school and university studentsâ narratives, Facebook posts and interviews, so that we can understand how students experience mainstreaming and inclusion. As opposed to the Facebook group, where students actively discuss their problems, in the research secondary school students were silent. Only university studentsâ voices could be heard. This passive attitude provokes numerous questions: What makes them silent? Is it the loneliness of mainstreaming? Are they too often misunderstood? Are they treated according to stereotypes? Studentsâ voices imply that teacher education needs reconsideration, and that, except for the cultural model of disability, each model fails to paint a holistic picture of disabled peopleâs lives. Listening to studentsâ voices is not only an important part of the cultural context but also a basic need without which both mainstream and inclusive education remains pure theory.peer-reviewe
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