4,842 research outputs found

    Affinity of Cherednik algebras on projective space

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    We give sufficient conditions for the affinity of Etingof's sheaves of Cherednik algebras on projective space. To do this we introduce the notion of pull-back of modules under certain flat morphisms.Comment: 20 page

    Recent Advances in Pediatric Use of Oral Paracetamol in Fever and Pain Management

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    Paracetamol is a common analgesic and antipyretic drug for management of fever and mild-to-moderate pain in infants and children, and it is considered as first-line therapy for the treatment of both according to international guidelines and recommendations. The mechanism of action of paracetamol is complex and multifactorial, and several aspects of the pharmacology impact its clinical use, especially in the selection of the correct analgesic and antipyretic dose. A systematic literature search was performed by following procedures for transparent reporting of systematic reviews and meta-analyses. To maximize efficacy and avoid delays in effect, use of the appropriate dose of paracetamol is paramount. Older clinical studies using paracetamol at subtherapeutic doses of ≀10 mg/kg generally show that it is less effective than non-steroidal anti-inflammatory drugs (NSAIDs). However, recent evidence shows that when used at dose of 15 mg/kg for fever and pain management, paracetamol is significantly more effective than placebo, and at least as effective as NSAIDs. Paracetamol 15 mg/kg has a tolerability profile similar to that of placebo and NSAIDs such as ibuprofen and ketoprofen used for short-term treatment of fever. However, when used at repetitive doses for consecutive days, paracetamol shows lower risk of adverse events compared to NSAIDs. Also, unlike NSAIDs, paracetamol is indicated for use in children of all ages. Overall, clinical evidence qualifies paracetamol 15 mg/kg a safe and effective option for treatment of pain and fever in children

    The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle

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    Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis

    Symplectic reflection algebras and Poisson geometry

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    The subject of this thesis is the Poisson geometry of varieties associated to the centres of symplectic reflection algebras in the PI case. In particular it focuses on describing the symplectic leaves of these varieties. Chapter 1 introduces the theory of symplectic reflection algebras. We introduce the classical objects of rings of invariants and skew group rings and describe deformations of these and present some of their basic properties following [26]. We highlight a dichotomy in the theory and focus our attention to the PI case. The framework for studying the representation theory is developed and the close connection with Poisson geometry is explained using results of [11]. Poisson algebras are introduced and the fundamental notion of stratifying Poisson varieties by symplectic leaves is explained. Although symplectic leaves are a well-known concept in the field of Poisson manifolds (see [55] and [79]) we examine them in the context of Poisson algebraic geometry as described in [11]. At the heart of Chapter 2 is the example of representations of deformed preprojective algebras and we view different aspects of the geometry of these varieties. The necessary invariant theory is introduced, which involves discussing the categorical quotient and its properties as in [68] or [48]. Crucial to us will be the stratification by orbit type. Moment maps and Marsden-Weinstein reductions for symplectic varieties are introduced following the approach of [15]. Combinatorial aspects of quivers are examined, in particular this includes the description by root vectors of orbit type strata for representations of preprojective algebras, as given in [16] and [17]. Finally hyper- Kahler manifolds make an appearance and provide a means for establishing the existence of the local normal form of the moment map, as was proved in [63]. The local normal form plays a crucial role in our main theorem concerning symplectic leaves, Theorem 4.2. Chapter 3 combines filtered and gi'aded techniques with the properties of symplectic leaves to establish that the associated variety of a Poisson prime ideal of the centre of a syraplectic reflection algebra is irreducible. The arguments used are ba

    Chapter Disegno: letture integrate per l’interpretazione di conoscenze e competenze pre ingresso al PoliTO

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    The 43rd UID conference, held in Genova, takes up the theme of ‘Dialogues’ as practice and debate on many fundamental topics in our social life, especially in these complex and not yet resolved times. The city of Genova offers the opportunity to ponder on the value of comparison and on the possibilities for the community, naturally focused on the aspects that concern us, as professors, researchers, disseminators of knowledge, or on all the possibile meanings of the discipline of representation and its dialogue with ‘others’, which we have broadly catalogued in three macro areas: History, Semiotics, Science / Technology. Therefore, “dialogue” as a profitable exchange based on a common language, without which it is impossible to comprehend and understand one another; and the graphic sign that connotes the conference is the precise transcription of this concept: the title ‘translated’ into signs, derived from the visual alphabet designed for the visual identity of the UID since 2017. There are many topics which refer to three macro sessions: - Witnessing (signs and history) - Communicating (signs and semiotics) - Experimenting (signs and sciences) Thanks to the different points of view, an exceptional resource of our disciplinary area, we want to try to outline the prevailing theoretical-operational synergies, the collaborative lines of an instrumental nature, the recent updates of the repertoires of images that attest and nourish the relations among representation, history, semiotics, sciences

    Qualitative Attributes of Commercial Pig Meat from an Italian Native Breed: The Nero d'Abruzzo

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    The main objective of this study was to characterize the main qualitative properties of commercial meat obtained from the Nero d'Abruzzo pig, a native breed of Central Italy. In order to valorize this animal production, a direct comparison was made with commercial meat products obtained from hybrid pigs. Over a period of 30 days, 76 steaks for each breed were purchased from the market, and samples were analyzed for total lipid content, fatty acids profile, Coenzyme Q10 content, resistance of meat to oxidative processes, volatile profile of cooked meat and electrophoretic profile of myofibrillar and sarcoplasmic proteins. Results showed the Nero d'Abruzzo to be richer in fat, which, however, is characterized by a higher concentration of alpha-linolenic acid, to which are attributed important health benefits. The native breed was also richer in Coenzyme Q10, a compound credited with antioxidant potential, whose presence could explain the better oxidative stability of meat samples that were cooked and stored for up to 7 days at +4 degrees C. In support of this last data, our finding of the characterization of the volatile profile of cooked meat, at the end of the storage period, showed in Nero d'Abruzzo a reduction in the accumulation of hexanal, notoriously associated with oxidative events and the development of unpleasant aromatic notes. In conclusion, aspects that can justify the nutritional superiority of this niche production compared to meat coming from cosmopolitan breeds have been identified

    Automatic detection of DNS manipulations

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    The DNS is a fundamental service that has been repeatedly attacked and abused. DNS manipulation is a prominent case: Recursive DNS resolvers are deployed to explicitly return manipulated answers to users' queries. While DNS manipulation is used for legitimate reasons too (e.g., parental control), rogue DNS resolvers support malicious activities, such as malware and viruses, exposing users to phishing and content injection. We introduce REMeDy, a system that assists operators to identify the use of rogue DNS resolvers in their networks. REMeDy is a completely automatic and parameter-free system that evaluates the consistency of responses across the resolvers active in the network. It operates by passively analyzing DNS traffic and, as such, requires no active probing of third-party servers. REMeDy is able to detect resolvers that manipulate answers, including resolvers that affect unpopular domains. We validate REMeDy using large-scale DNS traces collected in ISP networks where more than 100 resolvers are regularly used by customers. REMeDy automatically identifies regular resolvers, and pinpoint manipulated responses. Among those, we identify both legitimate services that offer additional protection to clients, and resolvers under the control of malwares that steer traffic with likely malicious goals
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