439 research outputs found
Structural properties and quasiparticule energies of cubic SrO, MgO and SrTiO3
The structural properties and the band structures of the charge-transfer
insulating oxides SrO, MgO and SrTiO3 are computed both within density
functional theory in the local density approximation (LDA) and in the Hedin's
GW scheme for self-energy corrections, by using a model dielectric function,
which approximately includes local field and dynamical effects. The deep
valence states are shifted by the GW method to higher binding energies, in very
good agreement with photoemission spectra. Since in all of these oxides the
direct gaps at high-symmetry points of the Brillouin zone may be very sensitive
to the actual value of the lattice parameter a, already at the LDA level,
self-energy corrections are computed both at the theoretical and the
experimental a. For MgO and SrO, the values of the transition energies between
the valence and the conduction bands are improved by GW corrections, while for
SrTiO3 they are overestimated. The results are discussed in relation to the
importance of local field effects and to the nature of the electronic states in
these insulating oxides.Comment: 3 figures, accepted in J. Phys.: Condens. Matte
Which Conference Is That? A Case Study in Computer Science
Conferences play a major role in some disciplines such as computer science and are often used in research quality evaluation exercises. Differently from journals and books, for which ISSN and ISBN codes provide unambiguous keys, recognizing the conference series in which a paper was published is a rather complex endeavor: There is no unique code assigned to conferences, and the way their names are written may greatly vary across years and catalogs. In this article, we propose a technique for the entity resolution of conferences based on the analysis of different semantic parts of their names. We present the results of an investigation of our technique on a dataset of 42,395 distinct computer science conference names excerpted from the DBLP computer science repository,1 which we automatically link to different authority files. With suitable data cleaning, the precision of our record linkage algorithm can be as high as 94%. A comparison with results obtainable using state-of-the-art general-purpose record linkage algorithms rounds off the article, showing that our ad hoc solution largely outperforms them in terms of the quality of the results
External Carotid Artery Shunting During Carotid Endarterectomy: An Alternative for Cerebral Protection?
AbstractObjectives: to assess the application of external carotid artery (ECA) shunting in cerebral protection during carotid endarterectomy (CEA). Design: prospective study. Materials and Methods: the study comprised 137 consecutive patients who underwent CEA under locoregional anaesthesia. Transcranial Doppler was used to monitor the mean velocity of the middle cerebral artery (mv-MCA): (1) before carotid clamping; (2) after clamping both the common and external carotid arteries; (3) after clamping the internal carotid artery alone (“ECA test”). The decision to shunt was based on the occurrence of neurological deficit during carotid clamping. If the ECA test revealed mv-MCA approaching the pre-clamping values ECA shunting was used, whereas the remaining patients in need of a shunt had a standard internal carotid artery (ICA) shunt. Results: shunting was necessary in 12/137 cases (9%). The ECA test indicated that in four cases – 3% of the whole series or 33% of the shunted cases. In these four patients ECA shunting reversed the neurological deficit, and CEA was successfully performed without any complications. Conclusions: ECA shunting could be considered as an alternative to standard ICA shunting. Suitable cases can be identified on the basis of the ECA test
The Power of Pivoting for Exact Clique Counting
Clique counting is a fundamental task in network analysis, and even the
simplest setting of -cliques (triangles) has been the center of much recent
research. Getting the count of -cliques for larger is algorithmically
challenging, due to the exponential blowup in the search space of large
cliques. But a number of recent applications (especially for community
detection or clustering) use larger clique counts. Moreover, one often desires
\textit{local} counts, the number of -cliques per vertex/edge.
Our main result is Pivoter, an algorithm that exactly counts the number of
-cliques, \textit{for all values of }. It is surprisingly effective in
practice, and is able to get clique counts of graphs that were beyond the reach
of previous work. For example, Pivoter gets all clique counts in a social
network with a 100M edges within two hours on a commodity machine. Previous
parallel algorithms do not terminate in days. Pivoter can also feasibly get
local per-vertex and per-edge -clique counts (for all ) for many public
data sets with tens of millions of edges. To the best of our knowledge, this is
the first algorithm that achieves such results.
The main insight is the construction of a Succinct Clique Tree (SCT) that
stores a compressed unique representation of all cliques in an input graph. It
is built using a technique called \textit{pivoting}, a classic approach by
Bron-Kerbosch to reduce the recursion tree of backtracking algorithms for
maximal cliques. Remarkably, the SCT can be built without actually enumerating
all cliques, and provides a succinct data structure from which exact clique
statistics (-clique counts, local counts) can be read off efficiently.Comment: 10 pages, WSDM 202
Consanguinity and polygenic diseases: a model for antibody deficiencies
Primary immunodeficiencies represent a heterogeneous group of disorders of the immune system, predisposing to various types of infections. Among them, common variable immunodeficiency is the most common symptomatic antibody deficiency. It includes several different forms characterized by defects in the terminal stage of B lymphocyte differentiation, leading to markedly reduced immunoglobulin serum levels and increased susceptibility to bacterial infections. The clinical phenotype is complex, including autoimmunity, granulomatous inflammation, lymphoproliferative disorders and malignancies. Rare autosomal recessive mutations in a number of single genes have recently been reported. However, the underlying genetic defects remain unknown in the majority of cases. In order to seek new genes responsible for the disease, we studied a consanguineous Italian family through exome sequencing combined with homozygosity mapping. Six missense homozygous variants passed our filtering selection and at least two of them were associated with some aspects of the pathological phenotype. Our data remark the complexity of immune system disorders and emphasize the difficulty to understand the significance of genetic results and their correlation with the disease phenotype
Gonadotropin-releasing hormone modulates cholesterol synthesis and steroidogenesis in SH-SY5Y cells.
An eleven-year history of Vanishing White Matter Disease in an adult patient with no cognitive decline and EIF2B5 mutations. A case report
Vanishing White Matter Disease (VWMD) is a rare autosomal recessive leukoencephalopathy. The classical presentation is characterized by a severe cerebellar ataxia, spasticity, neurological deterioration with a chronic progressive course and episodes of acute neurological deterioration after stress conditions. We report a 52-year-old man with VWMD and atypical features who manifested two major events of transient aphasia eleven years apart with complete recovery in 48 hours. No cognitive decline was present. Brain MRI revealed typical aspects of VWMD including diffuse leukoencephalopathy with relative sparing of U-fibers. We identified the presence of c.592G>A (p.Glu198Lys) and c.1360 C>T (p.Pro454Ser) mutations in EIF2B5
Tailored treatments in inborn errors of immunity associated with atopy (IEIs-A) with skin involvement
inborn errors of immunity associated with atopy (IEIs-A) are a group of inherited monogenic disorders that occur with immune dysregulation and frequent skin involvement. several pathways are involved in the pathogenesis of these conditions, including immune system defects, alterations of skin barrier and metabolism perturbations. current technological improvements and the higher accessibility to genetic testing, recently allowed the identification of novel molecular pathways involved in IEIs-A, also informing on potential tailored therapeutic strategies. compared to other systemic therapy for skin diseases, biologics have the less toxic and the best tolerated profile in the setting of immune dysregulation. Here, we review IEIs-A with skin involvement focusing on the tailored therapeutic approach according to their pathogenetic mechanism
- …