1,720,963 research outputs found
Arithmetics of homogeneous spaces over -adic function fields
Get PDFLet be the function field of a smooth projective geometrically integral
curve over a finite extension of . Following the works of Harari,
Scheiderer, Szamuely, Izquierdo, and Tian, we study the local-global and weak
approximation problems for homogeneous spaces of with
geometric stabilizers extension of a group of multiplicative type by a
unipotent group. The tools used are arithmetic (local and global) duality
theorems in Galois cohomology, in combination with techniques similar to those
used by Harari, Szamuely, Colliot-Th\'el\`ene, Sansuc, and Skorobogatov. As a
consequence, we show that any finite abelian group is a Galois group over ,
rediscovering the positive answer to the abelian case of the inverse Galois
problem over . In the case where the curve is defined over a
higher-dimensional local field instead of a finite extension of ,
coarser results are also given.Comment: 55 pages, major improvements from the previous versio
On the descent conjecture for rational points and zero-cycles
Get PDFThe descent method is one of the strategies allowing one to study the
Brauer--Manin obstruction to the local--global principle and to weak
approximation on varieties over number fields, by reducing the problem to
``descent varieties''. Very recently, in his Park City lecture notes,
Wittenberg formulated a ``descent conjecture'' for torsors under linear
algebraic groups. The present article gives a proof of this conjecture in the
case of connected groups, generalizing the toric case from the previous work of
Harpaz--Wittenberg. As an application, we deduce directly from Sansuc's work
the theorem of Borovoi for homogeneous spaces of connected linear algebraic
groups with connected stabilizers. We are also able to reduce the general case
to the case of finite (\'etale) torsors. When the set of rational points is
replaced by the Chow group of zero-cycles, an analogue of the above conjecture
for arbitrary linear algebraic groups is proved.Comment: 41 pages, fixed a gap in the proof of Proposition 2.7 on the
abelianization map, added the section on the descent conjecture for
zero-cycles, all the parts on non-abelian descent type have been separated
into arXiv:2401.0034
FIBEROPTIC ENDOSCOPIC EVALUATION OF SWALLOWING: EXPERIENCE AT THE NATIONAL REHABILITATION HOSPITAL (2019 - 2025)
No full textDysphagia is increasingly recognized due to higher survival rates after central nervous system injuries, head and neck cancer treatment, and in some cases in healthy elderly individuals. It leads to severe consequences including prolonged hospitalization, delayed recovery, recurrent pneumonia, and even mortality. Bedside clinical tests alone are insufficient for diagnosis. Fiberoptic Endoscopic Evaluation of Swallowing (FEES) is one of the gold standards in dysphagia assessment, proven to be safe, effective, and feasible worldwide. However, FEES has not been widely adopted in Vietnam. This paper reports the implementation and clinical experience of FEES at the National Rehabilitation Hospital between 2019 and 2025. Literature review and clinical experience were combined. More than 700 FEES procedures were performed between April 2019 and July 2025. FEES allowed direct visualization of swallowing physiology, identification of penetration/aspiration, and guided compensatory strategies. No serious complications were reported, apart from mild discomfort. FEES is an effective and safe diagnostic tool for dysphagia, supporting individualized management strategies and should be expanded in Vietnam
Non-abelian descent types
Get PDFWe present the notion of non-abelian descent type, which classifies torsors up to twisting by a Galois cocycle. This relies on the previous construction of kernels and non-abelian Galois 2-cohomology due to Springer and Borovoi. The necessity of descent types arises in the context of the descent theory where no torsors are given a priori, for example, when we wish to study the arithmetic properties such as the Brauer--Manin obstruction to the Hasse principle on homogeneous spaces without rational points. This new definition also unifies the types by Colliot-Thélène--Sansuc, the extended types by Harari--Skorobogatov, and the finite descent type by Harpaz--Wittenberg.39 pages, separated from arXiv:2305.13228 with some improvement
Groupes de Brauer alg\'ebriques modulo les constants d'espaces homog\`enes et leurs compactifications
Get PDFLet be a smooth, geometrically integral variety over a field . Then
the quotient of the "algebraic" Brauer group of by
injects into . We show that this
inclusion is not always an isomorphism, even in the case where is a
homogeneous space of a connected linear algebraic group over . A similar
result for the smooth compactifications of is also given. --
Soit une vari\'et\'e lisse, g\'eom\'etriquement int\`egre sur un corps
. Alors le quotient du groupe Brauer "alg\'ebrique" de par
s'injecte dans . Nous montrons que cette inclusion n'est pas toujours un isomorphisme
m\^eme dans le cas o\`u est un espace homog\`ene d'un groupe alg\'ebrique
lin\'eaire connexe sur . Un r\'esultat similaire pour les compactifications
lisses de est aussi donn\'e.Comment: 9 pages, in Frenc
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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