1,720,964 research outputs found
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
Renal damage and death in weaned mice after oral infection with Shiga toxin 2-producing Escherichia coli strains
No full textFil: Brando, R J F. División Inmunología, Instituto de Investigationes Hematológicas, Academia Nacional de Medicina; Argentina.Fil: Miliwebsky, Elizabeth. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Bentancor, L. División Inmunología, Instituto de Investigationes Hematológicas, Academia Nacional de Medicina; Argentina.Fil: Deza, N. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Baschkier, Ariela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Ramos, Marina A. División Inmunología, Instituto de Investigationes Hematológicas, Academia Nacional de Medicina; Argentina.Fil: Fernández, G. C. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Meiss, R. Departamento de Patología, Centro de Estudios Oncológicos, Academia Nacional de Medicina; Argentina.Fil: Rivas, Marta. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Palermo, M. División Inmunología, Instituto de Investigationes Hematológicas, Academia Nacional de Medicina; Argentina.Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infections are considered a public health problem in both developed and developing countries because of their increasing incidence and the severity of clinical presentation. Approximately 10% of infected patients develop complications such as haemolytic uraemic syndrome (HUS) characterized by acute renal failure, thrombocytopenia and haemolytic anaemia. The precise sequence of events leading to HUS is still understood incompletely. Because of the lack of a reproducible small animal model for EHEC infections, in vivo studies examining EHEC-host early interactions are limited and insufficient. The aim of this study was to characterize the weaned BALB/c mouse as a model of E. coli O157:H7 infection. In this paper we report that human Shiga toxin 2 (Stx2)-producing EHEC strains can adhere to the intestinal epithelium of weaned BALB/c mice, and produce local damage which leads to systemic disease and death in a percentage of infected mice. The lethality of the EHEC strain is closely age-dependent, and is related to the bacterial ability to colonize intestine and to produce Stx2. It can be concluded that the weaned BALB/c mouse can be used as a small animal model to study host early responses, and the role of bacterial pathogenic factors in the induction of systemic disease, thus providing a useful tool for the evaluation of therapeutic or vaccine approaches
Shiga toxin-producing Escherichia coli O157 in beef and chicken burgers, and chicken carcasses in Buenos Aires, Argentina
Get PDFFil: Chinen, Isabel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Epszteyn, Sergio. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Melamed, Celia L. Departamento Laboratorio Investigación y Monitoreo, Dirección General de Higiene y Seguridad Alimentaria, Gobierno de la Ciudad de Buenos Aires, Patricias Argentinas 277, (1405) Buenos Aires; Argentina.Fil: Aguerre, Lorena. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Martínez Espinosa, Estela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Motter, Mariana M. Departamento Laboratorio Investigación y Monitoreo, Dirección General de Higiene y Seguridad Alimentaria, Gobierno de la Ciudad de Buenos Aires, Patricias Argentinas 277, (1405) Buenos Aires; Argentina.Fil: Baschkier, Ariela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Manfredi, Eduardo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Miliwebsky, Elizabeth. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.Fil: Rivas, Marta. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio Fisiopatogenia; Argentina.We describe the isolation and characterization of Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 from cooked and uncooked beef and chicken burgers and from chicken carcasses collected during sampling procedures in 2001 and 2002 in Buenos Aires City, Argentina. Of the 24 STEC O157:H7 strains isolated, 20 were recovered from 19 (6.8%) out of 279 samples of beef and chicken burgers, and 4 strains from 4 (10.3%) out of 39 chicken carcasses. The samples were analyzed following the USDA/FSIS 2002 method. The prevalent stx genotype was stx(2) and stx(2c) (12 strains, 50%). All strains were characterized as eae and ehxA-positive. By XbaI-PFGE, the strains yielded 10 different patterns. Eighteen out of 24 strains were grouped in four clusters: #1 (4 strains, AREXHX01.0043), #2 (4 strains, AREXHX01.0022), #3 (8 strains, AREXHX01.0139), and #4 (2 strains, AREXHX01.0200). Identical strains by phage typing, stx genotyping and PFGE were detected in uncooked and cooked beef and chicken burgers in different restaurants, which had been collected on the same or different sampling dates. These findings help to underline the importance of STEC O157 detection in meat products, to improve active surveillance, and to define control strategies in order to prevent new cases of STEC infection
Immunization with a Chimera Consisting of the B Subunit of Shiga Toxin Type 2 and Brucella Lumazine Synthase Confers Total Protection against Shiga Toxins in Mice.
No full textThe striking feature of enterohemorrhagic Escherichia coli (EHEC) infections is the production of Shiga toxins (Stx) implicated in the development of the life-threatening hemolytic uremic syndrome. Despite the magnitude of the social impact of EHEC infections, no licensed vaccine or effective therapy is available for human use. One of the biggest challenges is to develop an effective and safe immunogen to ensure nontoxicity, as well as a strong input to the immune system to induce long-lasting, high-affinity Abs with anti-Stx–neutralizing capacity. The enzyme lumazine synthase from Brucella spp. (BLS) is a highly stable dimer of pentamers and a scaffold with enormous plasticity on which to display foreign Ags. Taking into account the advantages of BLS and the potential capacity of the B subunit of Stx2 to induce Abs that prevent Stx2 toxicity by blocking its entrance into the host cells, we engineered a new immunogen by inserting the B subunit of Stx2 at the amino termini of BLS. The resulting chimera demonstrated a strong capacity to induce a long-lasting humoral immune response in mice. The chimera induced Abs with high neutralizing capacity for Stx2 and its variants. Moreover, immunized mice were completely protected against i.v. Stx2 challenge, and weaned mice receiving an oral challenge with EHEC were completely protected by the transference of immune sera. We conclude that this novel immunogen represents a promising candidate for vaccine or Ab development with preventive or therapeutic ends, for use in hemolytic uremic syndrome–endemic areas or during future outbreaks caused by pathogenic strains of Stx-producing E. coli.Fil: Mejias, Maria Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental; ArgentinaFil: Ghersi, Giselle. Inmunova S.a; ArgentinaFil: Craig, Patricio Oliver. Fundación Instituto Leloir; ArgentinaFil: Panek, Cecilia Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental; ArgentinaFil: Bentancor, Leticia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental; ArgentinaFil: Baschkier, Ariela. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Goldbaum, Fernando Alberto. Inmunova S.a; Argentina. Fundación Instituto Leloir; ArgentinaFil: Zylberman, Vanesa. Inmunova S.a; Argentina. Fundación Instituto Leloir; ArgentinaFil: Palermo, Marina Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental; Argentin
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
Hemorragia y oclusión intestinal asociadas a escherichia coli O127:H21 productor de toxina shiga
No full textWe report a case of a nine-year old boy with vomiting, abdominal pain and fever, who underwent surgery with a diagnosis of appendicitis in Mendoza and from whom a Shiga toxin-producing Escherichia coli (STEC) O127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Laboratory findings included: hematocrit, 35%; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildly hydrated child, without fever but with distended and painful abdomen. The patient was again submitted to surgery with a diagnosis of intestinal occlusion. Bleeding and multiple adhesions in jejunum and ileum were found. The patient still had tense and painful abdomen and presented two bowel movements with blood; hematocrit fell to 29% and blood urea nitrogen rose to 0.32 g/L. STEC O127:H21 eae(-)/Stx2/Stx2vh-b(+)/E-Hly(+) was isolated from a stool sample. He was discharged after 10 days of hospitalization and no long-term complications such as HUS or TTP were observed. This is the first report, to our knowledge, on the isolation of E. coli O127:H21, carrying the virulence factors that characterize STEC strains, associated to an enterohemorrhagic colitis case. This serotype was previously characterized as a non-classic enteropathogenic E. coli (EPEC). STEC infections can mimic infectious or noninfectious pathologies. Therefore an important aspect of clinical management is making the diagnosis using different criteria thereby avoiding misdiagnoses which have occasionally led to invasive diagnostic and therapeutic procedures or the inappropriate use of antibiotics.Se presenta el caso de un niño de 9 años, eutrófico, perteneciente a una familia de bajo nivel socioeconómico en Mendoza, que ingresó al hospital con vómitos, fiebre y dolor abdominal y al cual se le practicó apendectomía, aislándose Escherichia coli O127:H21, productor de toxina Shiga (STEC) en el coprocultivo. A las 48 horas post-cirugía, el paciente presentó vómitos biliosos y dos episodios de hemorragia intestinal. El hematocrito fue de 35% y la uremia de 0.22 g/L. La diuresis fue normal. Al día siguiente estaba afebril, alerta, hidratado, pero con el abdomen distendido y doloroso. Fue enviado nuevamente a cirugía con diagnóstico de oclusión intestinal, observándose durante la misma, sangrado intestinal y múltiples adherencias en yeyuno e íleo, que fueron manualmente removidas. El paciente continuó con distensión abdominal y presentó dos deposiciones sanguinolentas, el hematocrito disminuyó a 29% y la urea en sangre se elevó a 0.32 g/L. STEC O127:H21 eae(-)/Stx2/Stx2vh-b(+)/ E-Hly(+) fue aislado de la materia fecal. El niño fue dado de alta después de 10 días de hospitalización sin presentar complicaciones como SUH o PTT. Esta es la primera comunicación sobre el aislamiento de E. coli O127:H21 de un caso de enterocolitis hemorrágica, con los factores de virulencia que caracterizan a STEC. Este serotipo era reconocido como perteneciente a la categoría de E. coli enteropatógeno no clásico. Teniendo en cuenta que las infecciones por STEC pueden mimetizar otras patologías infecciosas o no infecciosas, es importante utilizar distintos criterios diagnósticos, para evitar prácticas médicas o tratamientos innecesarios.Fil: Rivas, Marta. ANLIS Dr.C.G.Malbrán, Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Miliwebsky, Elizabeth. ANLIS Dr.C.G.Malbrán, Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Balbi, Laura. Hospital Pediátrico Dr. Humberto Notti; Argentina.Fil: García, Beatriz. Hospital Pediátrico Dr. Humberto Notti; Argentina.Fil: Leardini, Nelida. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Microbiología; Argentina.Fil: Tous, Monica. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Microbiología; Argentina.Fil: Chillemi, German. ANLIS Dr.C.G.Malbrán, Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Baschkier, Ariela. ANLIS Dr.C.G.Malbrán, Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Strugo, Liliana. Hospital Pediátrico Dr. Humberto Notti; Argentina
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