170,713 research outputs found
Social Influence Given (Partially) Deliberate Matching: Career Imprints in the Creation of Academic Entrepreneurs
No full textActors often match with associates on a small set of dimensions that matter most for the particular relationship at hand. In so doing, they are exposed to unanticipated social influences because counterparts have more interests, attitudes, and preferences than would-be associates considered when they first chose to pair. This implies that some apparent social influences (those tied to the rationales for forming the relationship) are endogenous to the matching process, while others (those that are incidental to the formation of the relationship) may be conditionally exogenous, thus enabling causal estimation of peer effects. We illustrate this idea in a new dataset tracking the training and professional activities of academic biomedical scientists. In qualitative and quantitative analyses, we show that scientists match to their postdoctoral mentors based on two dominant factors, geography and scientific focus. They then adopt their advisers' orientations toward commercial science as evidenced by the transmission of patenting behavior, but they do not match on this dimension. We demonstrate this in two-stage models that adjust for the endogeneity of the matching process, using a modification of propensity score estimation and a sample selection correction with valid exclusion restrictions. Furthermore, we draw on qualitative accounts of the matching process recorded in oral histories of the career choices of the scientists in our data. All three methods-qualitative description, propensity score estimators, and those that tackle selection on unobservable factors-are potential approaches to establishing evidence of social influence in partially endogenous networks, and they may be especially persuasive in combination.
Early Re-Operation for Bleeding after Liver Transplantation Has a Severe Prognostic Impact on Prognosis in the Modern Era
No full textA simple technique for procuring liver allografts while protecting arterial vessels
No full textArterial injury remains a common complication during organ procurement, with negative effects on postoperative morbidity and graft survival. We describe a simple technique that helps surgeons avoid vascular injuries during isolated liver procurement (without pancreas). This simple technique has been used in 200 liver procurements without any arterial injuries
Liver Transplantation from Brain Dead Donors > 70 Years Old into Patients with MELD Score > 20
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Vincent Azoulay, Les Tyrannicides d’Athènes. Vie et mort de deux statues
No full textMembre junior de l’Institut universitaire de France depuis 2010, Vincent Azoulay (VA) a mis à profit les excellentes conditions de travail qui lui sont offertes pour écrire la biographie des statues des Tyrannicides. Cette approche originale fait l’intérêt d’une enquête qui éclaire sous un jour nouveau non seulement ce monument bien connu mais aussi l’histoire politique grecque. Dans une introduction argumentée (p. 11-24), VA rappelle comment l’assassinat d’Hipparque en 514 av. J.-C. par deu..
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Social Influence Given (Partially) Deliberate Matching: Career Imprints in the Creation of Academic Entrepreneurs
No full textActors and associates often match on a few dimensions that matter most for the relationship at hand. In so doing, they are exposed to unanticipated social influences because counterparts have broader attitudes and preferences than would-be contacts considered when they first chose to pair. The authors label as “partially deliberate” social matching that occurs on a small set of attributes, and they present empirical methods for identifying causal social influence effects when relationships follow this generative logic. A data set tracking the training and professional activities of academic biomedical scientists is used to show that young scientists adopt their advisers’ orientations toward commercial science as evidenced by adviser-to-advisee transmission of patenting behavior. The authors demonstrate this in twostage models that account for the endogeneity of matching, using both inverse probability of treatment weights and an instrumental variables approach. They also draw on qualitative methods to support a causal interpretation. Overall, they present a theory and a triangulation of methods to establish evidence of social influence when tie formation is partially deliberate
The Diffusion of Scientific Knowledge Across Time and Space: Evidence from Professional Transitions for the Superstars of Medicine
No full textAre scientific knowledge flows embodied in individuals, or "in the air"? To answer this question, we measure the effect of labor mobility in a sample of 9,483 elite academic life scientists on the citation trajectories associated with individual articles (resp. patents) published (resp. granted) before the scientist moved to a new institution. We find that article-to-article citations from the scientific community at the superstar's origin location are barely affected by their departure. In contrast, article-to-patent citations, and especially patent-to-patent citations, decline at the origin location following a star's departure, suggesting that spillovers from academia to industry are not completely disembodied. We also find that article-to-article citations at the superstar's destination location markedly increase after they move. Our results suggest that, to be realized, knowledge flows to industry may require more face-to-face interaction than those to academics. Moreover, to the extent that academic scientists do not internalize the effect of their location decisions on the circulation of ideas, our results raise the intriguing possibility that barriers to labor mobility in academic science limit the recombination of individual bits of knowledge, resulting in a suboptimal rate of scientific exploration.
Outcomes after 3D laparoscopic and robotic liver resection for hepatocellular carcinoma: a multicenter comparative study
No full textBackground: The recent development of 3D vision in laparoscopic and robotic surgical systems raises the question of whether these two procedures are equivalent. The aim of this study was to evaluate the surgical and long-term oncological outcomes of 3D laparoscopic (3D-LLR) and robotic liver resection (RLR) for hepatocellular carcinoma (HCC). Methods: The data for operative time, morbidity, margins, and survival were reviewed for 3D-LLR and compared with RLR. Results: From 2011 to 2017, 93 patients with HCC, including 58 (62%) with cirrhosis, underwent 3D-LLR [49 (53%)] or RLR [44 (47%)]. No difference was observed in operative time (269 vs. 252 min; p = 0.52), overall (27% vs. RLR: 16%; p = 0.49) and severe morbidity (4% vs. 2%; p = 0.77) or in the surgical margin width (9 vs. 11 mm; p = 0.30) between the 3D-LLR and RLR groups. The 3-year overall and recurrence-free survival rates after 3D-LLR and RLR were 82% and 24% and 91% (p = 0.16) and 48% (p = 0.18), respectively. Conclusions: The 3D-LLR and RLR systems provide comparable surgical margins with similar short- and long-term oncological outcomes
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