3,414 research outputs found
Line bundles for which a projectivized jet bundle is a product
We characterize the triples (X,L,H), consisting of holomorphic line bundles L
and H on a complex projective manifold X, such that for some positive integer
k, the k-th holomorphic jet bundle of L, J_k(L), is isomorphic to a direct sum
H+...+H. Given the geometrical constrains imposed by a projectivized line
bundle being a product of the base and a projective space it is natural to
expect that this would happen only under very rare circumstances. It is shown,
in fact, that X is either an Abelian variety or projective space. In the former
case L\cong H is any line bundle of Chern class zero. In the later case for k a
positive integer, L=O_{P^n}(q) with J_k(L)=H+...+H if and only if
H=O_{P^n}(q-k) and either q\ge k or q\le -1.Comment: Latex file, 5 page
Wie entscheiden sich Schülerinnen für oder gegen eine HPV-Impfung?
Zusammenfassung: Hintergrund: 2007 wurde die HPV- ("human papilloma virus-")Impfung in der Schweiz eingeführt und in der Stadt Zürich mittels einer Impfaktion des Schulärztlichen Dienstes 2008 allen Schülerinnen zwischen 11 und 16Jahren gratis angeboten. Danach impft der Schulärztliche Dienst im Rahmen einer Schulärztlichen Untersuchung in der 6. Und 8. Klasse. Die HPV-Impfung ist in der Schweiz umstritten und wird nicht selten, v.a. von impfkritischen Eltern, als überflüssig kritisiert. Ziel: Das Ziel der vorgestellten Studie war zu ermitteln, wie 13- bis 15-jährige Schülerinnen die Entscheidung für oder gegen die Impfung treffen, und von welchen Akteuren sie in ihrer Entscheidungsfindung beeinflusst werden. Ergebnis: Der größte Einflussfaktor bei der Entscheidung für oder gegen die Impfung sind die Eltern, insbesondere die Mütter der Schülerinnen. Diese sind ihrerseits von Frauen- und Kinderärzten beeinflusst. Die Medien, die Lehrpersonen sowie die Peers spielen eine eher untergeordnete Rolle. Insgesamt zeigen viele Akteure eine impfkritische Einstellung, die aber nur teilweise ausgesprochen wird. Um eine bessere Akzeptanz zu erreichen, müsste deshalb ein ganzheitlicher Entscheidungsprozess in den Schulen angestrebt werden, der alle Akteure mit einbezieh
Linear Toric Fibrations
These notes are based on three lectures given at the 2013 CIME/CIRM summer
school. The purpose of this series of lectures is to introduce the notion of a
toric fibration and to give its geometrical and combinatorial
characterizations. Polarized toric varieties which are birationally equivalent
to projective toric bundles are associated to a class of polytopes called
Cayley polytopes. Their geometry and combinatorics have a fruitful interplay
leading to fundamental insight in both directions. These notes will illustrate
geometrical phenomena, in algebraic geometry and neighboring fields, which are
characterized by a Cayley structure. Examples are projective duality of toric
varieties and polyhedral adjunction theory
Sirtuins 1–7 expression in human adipose-derived stem cells from subcutaneous and visceral fat depots: influence of obesity and hypoxia
The sirtuin family comprises seven NAD+-dependent deacetylases which control the overall health of organisms through the regulation of pleiotropic metabolic pathways. Sirtuins are important modulators of adipose tissue metabolism and their expression is higher in lean than obese subjects. At present, the role of sirtuins in adipose-derived stem cells has not been investigated yet. Therefore, in this study, we evaluated the expression of the complete panel of sirtuins in adipose-derived stem cells isolated from both subcutaneous and visceral fat of non-obese and obese subjects. We aimed at investigating the influence of obesity on sirtuins' levels, their role in obesity-associated inflammation, and the relationship with the peroxisome proliferator-activated receptor delta, which also plays functions in adipose tissue metabolism. The mRNA levels in the four types of adipose-derived stem cells were evaluated by quantitative polymerase chain reaction, in untreated cells and also after 8 h of hypoxia exposure. Correlations among sirtuins' expression and clinical and molecular parameters were also analyzed. We found that sirtuin1-6 exhibited significant higher mRNA expression in visceral adipose-derived stem cells compared to subcutaneous adipose-derived stem cells of non-obese subjects. Sirtuin1-6 levels were markedly reduced in visceral adipose-derived stem cells of obese patients. Sirtuins' expression in visceral adipose-derived stem cells correlated negatively with body mass index and C-reactive protein and positively with peroxisome proliferator-activated receptor delta. Finally, only in the visceral adipose-derived stem cells of obese patients hypoxia-induced mRNA expression of all of the sirtuins. Our results highlight that sirtuins' levels in adipose-derived stem cells are consistent with protective effects against visceral obesity and inflammation, and suggest a transcriptional mechanism through which acute hypoxia up-regulates sirtuins in the visceral adipose-derived stem cells of obese patients
Local anaesthesia efficacy as postoperative analgesia for open shoulder instability surgery. a prospective randomised controlled study
Background and objectives: The aim of present study was to evaluate for the first time, the clinical effect of local anaesthetic infiltration as postoperative analgesia in open shoulder surgery for anterior-inferior instability. The comparison of the local infiltration and interscalenic brachial plexus block to a control group test the local anaesthetic efficacy in this surgery.
Methods: 78 patients scheduled for open shoulder surgery were enrolled and randomly assigned to one of three groups: local infiltration anaesthesia (LIA), interscalenic brachial plexus block (IBPB) and control (C). All patients received standardized general anaesthesia and all injections were performed with the same dose and volume of anaesthetic. The number boluses delivered by a PCA pump applied at the end of surgery and the visual analogue score (VAS) at 0, 2, 4, 6, 12, 18 and 24 hours after intervention were recorded. A patient satisfaction score was also assessed.
Results: Mean bolus consumption of the rescue analgesic, compared to C, was significantly less both in the LIA and IBPB groups (P<0.05). The IBPB group showed VAS scores that were significantly better than C group at all time points (P<0.05). The VAS scores for LIA group were clinically comparable to IBPB, and only at the 2 and 6 hours, postoperative time points there were no significant differences found in respect to the C group. IBPB and LIA showed comparable patient satisfaction scores.
Conclusion: The local anaesthetic infiltration as postoperative analgesia appears to be a clinically valid alternative, statistically comparable to IBPB, with no clinical meaningful adverse effects
Enhancement of photoacoustic detection of inhomogeneities in polymers
We report a series of experiments on laser pulsed photoacoustic excitationin
turbid polymer samples addressed to evaluate the sound speed in the samples and
the presence of inhomogeneities in the bulk. We describe a system which allows
the direct measurement of the speed of the detected waves by engraving the
surface of the piece under study with a fiduciary pattern of black lines. We
also describe how this pattern helps to enhance the sensitivity for the
detection of an inhomogeneity in the bulk. These two facts are useful for
studies in soft matter systems including, perhaps, biological samples. We have
performed an experimental analysis on Grilon(R) samples in different situations
and we show the limitations of the method.Comment: 8 pages, 7 figure
Longitudinal sleeve gastrectomy: current perspectives
Emanuele Soricelli, Giovanni Casella, Giorgio Di Rocco, Adriano Redler, Nicola BassoDepartment of Surgical Sciences, Policlinico Umberto I, Sapienza, University of Rome, ItalyAbstract: Since the early 2000s, laparoscopic sleeve gastrectomy has increasingly gained consensus in bariatric surgery, thanks to good to excellent results in terms of weight loss and comorbidity resolution, and to simpler technical aspects than in Roux-en-Y gastric bypass and biliopancreatic diversion. In yearly consensus summits, surgical indications, technical details, and management of complications, together with continuous update of data concerning clinical outcome, have been debated on the basis of increasing collective experience. In experimental studies and clinical trials, the pathophysiological mechanisms of weight loss and remission of cardiometabolic comorbidities subsequent to sleeve gastrectomy have been extensively discussed. The aim of this paper is to offer a review of state of the art laparoscopic sleeve gastrectomy and to focus attention on the currently most debated topics and future prospects of this procedure.Keywords: sleeve gastrectomy, type 2 diabetes mellitus, gastroesophageal reflux disease, revisional, quality of lif
HISTORICAL EARTHEN WALLS: FROM KNOWLEDGE TO CONSCIOUS CONSERVATION
Abstract. Centuries-old earthen masonry presenting various stages of degradation, earthen walls that have been restored several times: these are the archeological phases of the city walls of Mascarell, on the Spanish Mediterranean coast. Founded in the first half of the 13th century, this town is the only complex in Castellon Province that preserves all its ancient walls, which were built entirely by means of the brick-faced rammed-earth technique (clay with bricks and lime). This article reports the first results of a research project conducted on the multiple information available on these artifacts: bibliographic, archival and iconographic sources and the results of direct material analysis, stratigraphic analysis and archeological analysis. The situation is complex, as these walls have undergone a long sequence of transformations, including interventions carried out since the 18th century and multiple restorations in the period 1942–2015. The research developed and refined architecture archeology tools in order to analyze the rammed-earth techniques adopted during restoration work (similar but not identical to the historical technique), to characterize the materials used in restoration, to evaluate their resistance to degradation over the years, to define a sort of 'critical evolutionary line' of rammed-earth restoration, and to conduct a cross-sectional study of this building technique from the Middle Ages to the present. Finally, we drafted some guidelines for future interventions for conservation and enhancement
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