30 research outputs found

    Implicit Complexity over an Arbitrary Structure: Quantifier Alternations

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    Rapport interne.We provide machine-independent characterizations of some complexity classes, over an arbitrary structure, in the model of computation proposed by L.~Blum, M.~Shub and S.~Smale. We show that the levels of the polynomial hierarchy correspond to safe recursion with predicative minimization and the levels of the digital polynomial hierarchy to safe recursion with digital predicative minimization. Also, we show that polynomial alternating time corresponds to safe recursion with predicative substitutions and that digital polynomial alternating time corresponds to safe recursion with digital predicative substitutions

    Grimace scale, burrowing, and nest building for the assessment of post-surgical pain in mice and rats-A systematic review

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    Several studies suggested an informative value of behavioral and grimace scale parameters for the detection of pain. However, the robustness and reliability of the parameters as well as the current extent of implementation are still largely unknown. In this study, we aimed to systematically analyze the current evidence-base of grimace scale, burrowing, and nest building for the assessment of post-surgical pain in mice and rats. The following platforms were searched for relevant articles: PubMed, Embase via Ovid, and Web of Science. Only full peer-reviewed studies that describe the grimace scale, burrowing, and/or nest building as pain parameters in the post-surgical phase in mice and/or rats were included. Information about the study design, animal characteristics, intervention characteristics, and outcome measures was extracted from identified publications. In total, 74 papers were included in this review. The majority of studies have been conducted in young adult C57BL/6J mice and Sprague Dawley and Wistar rats. While there is an apparent lack of information about young animals, some studies that analyzed the grimace scale in aged rats were identified. The majority of studies focused on laparotomy-associated pain. Only limited information is available about other types of surgical interventions. While an impact of surgery and an influence of analgesia were rather consistently reported in studies focusing on grimace scales, the number of studies that assessed respective effects was rather low for nest building and burrowing. Moreover, controversial findings were evident for the impact of analgesics on post-surgical nest building activity. Regarding analgesia, a monotherapeutic approach was identified in the vast majority of studies with non-steroidal anti-inflammatory (NSAID) drugs and opioids being most commonly used. In conclusion, most evidence exists for grimace scales, which were more frequently used to assess post-surgical pain in rodents than the other behavioral parameters. However, our findings also point to relevant knowledge gaps concerning the post-surgical application in different strains, age levels, and following different surgical procedures. Future efforts are also necessary to directly compare the sensitivity and robustness of different readout parameters applied for the assessment of nest building and burrowing activities

    Anesthesia and analgesia for experimental craniotomy in mice and rats: a systematic scoping review comparing the years 2009 and 2019

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    Experimental craniotomies are a common surgical procedure in neuroscience. Because inadequate analgesia appears to be a problem in animal-based research, we conducted this review and collected information on management of craniotomy-associated pain in laboratory mice and rats. A comprehensive search and screening resulted in the identification of 2235 studies, published in 2009 and 2019, describing craniotomy in mice and/or rats. While key features were extracted from all studies, detailed information was extracted from a random subset of 100 studies/year. Reporting of perioperative analgesia increased from 2009 to 2019. However, the majority of studies from both years did not report pharmacologic pain management. Moreover, reporting of multimodal treatments remained at a low level, and monotherapeutic approaches were more common. Among drug groups, reporting of pre- and postoperative administration of non-steroidal anti-inflammatory drugs, opioids, and local anesthetics in 2019 exceeded that of 2009. In summary, these results suggest that inadequate analgesia and oligoanalgesia are persistent issues associated with experimental intracranial surgery. This underscores the need for intensified training of those working with laboratory rodents subjected to craniotomies.Systematic review registrationhttps://osf.io/7d4qe

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Résultats de complétude et caractérisations syntaxiques de classes de complexité sur des structures arbitraires

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    Nous nous plaçons dans le modèle de calcul BSS sur des structures arbitraires. Nous présentons de nouveaux résultats de complétude concernant des problèmes géométriques sur les nombres réels avec addition et ordre. Nous présentons aussi plusieurs caractérisations de classes de complexité indépendantes du modèle de calcul sous-jacent. Nous êtendons des résultats de Gradel, Gurevich et Meer en complexité descriptive, qui caractérisent les prob- lèmes de décisions calculables en temps polynomial déterministe et non-déterministe en termes de logique sur des structures métafinies. Nous étendons des résultats de Bellantoni et Cook pour caractériser les fonctions calculables en temps polynomial sêquentiel, et de Leivant et Marion pour caractériser les fonctions calculables en temps polynomial parallèle, en termes d'algèbres de fonctions récursives. Nous présentons également des caractérisations de fonctions calculables dans la hiérarchie polynomiale et en temps polynomial alternant.We focus on the BSS model of computation over arbitrary structures. We provide new completeness results for geometrical problems when this structure is the set of real numbers with addition and order. We also provide several machine independent characterizations of complexity classes over arbitrary structures. We extend some results by Gradel, Gurevich and Meer in descriptive complexity, characterizing deterministic and non deterministic polynomial.time decision problems in terms of logics over metaflnite structures. We extend some results by Bellantoni and Cook, characterizing functions computable in sequential determin- isitc polynomial time, and by Leivant and Marion, characterizing functions computable in parallel determinisitc polynomial time in terms of algebras of recursive functions. We also provide some characterizations of functions computable within the polynomial hierarchy and in polynomial alternating time.NANCY/VANDOEUVRE-INPL (545472102) / SudocSudocFranceF

    Safe Recursion and Calculus over an Arbitrary Structure

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    Colloque avec actes et comité de lecture. internationale.International audienceIn this paper, we show that the Bellantoni and Cook characterization of polynomial time computable functions in term of safe recursive functions can be transfered to the model of computation over an arbitrary structure developped by L. Blum, M. Shub and S. Smale. Hence, we provide an implicit complexity characterization of functions computable in polynomial time over any arbitrary structure

    Mechanism for rapid passive-dynamic prey capture in a pitcher plant

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    catch animal prey. Most rapid-release mechanisms only work once and, if repeatable, regaining the prerelease state is a slow and costly process. We present an encompassing mechanism for a rapid, repeatable, passive-dynamic motion used by a carnivorous pitcher plant to catch prey. Nepenthes gracilis uses the impact of rain drops to catapult insects from the underside of the canopy-like pitcher lid into the fluid-filled trap below. High-speed video and laser vibrometry revealed that the lid acts as a torsional spring system, driven by rain drops. During the initial downstroke, the tip of the lid reached peak velocities similar to fast animal motions and an order of magnitude faster than the snap traps of Venus flytraps and catapulting tentacles of the sundew Drosera glanduligera. In contrast to these active movements, the N. gracilis lid oscillation requires neither mechanical preloading nor metabolic energy, and its repeatability is only limited by the intensity and duration of rainfall. The underside of the lid is coated with friction-reducing wax crystals, making insects more vulnerable to perturbations. We show that the trapping success of N. gracilis relies on the combination of material stiffness adapted for momentum transfer and the antiadhesive properties of the wax crystal surface. The impact-driven oscillation of the N. gracilis lid represents a new kind of rapid plant movement with adaptive function. Our findings establish the existence of a continuum between active and passive trapping mechanisms in carnivorous plants

    Safe Recursion over an Arbitrary Structure: Deterministic Polynomial Time

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    Rapport interne.In this paper, we provide several machine-independent characterizations of deterministic complexity classes in the model of computation proposed by L. Blum, M. Shub and S. Smale. We provide a characterization of partial recursive functions over any arbitrary structure. We show that polynomial time computable functions over any arbitrary structure can be characterized in term of safe recursive functions. We show that polynomial parallel time decision problems over any arbitrary structure can be characterized in terms of safe recursive functions with substitutions

    Implicit Complexity over an Arbitrary Structure: Quantifier Alternations

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    We provide machine-independent characterizations of some complexity classes, over an arbitrary structure, in the model of computation proposed by L. Blum, M. Shub and S. Smale. We show that the levels of the polynomial hierarchy correspond to safe recursion with predicative minimization and the levels of the digital polynomial hierarchy to safe recursion with digital predicative minimization. Also, we show that polynomial alternating time corresponds to safe recursion with predicative substitutions and that digital polynomial alternating time corresponds to safe recursion with digital predicative substitutions
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