1,446 research outputs found

    Filtering Irreducible Clifford Supermodules

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    A Clifford algebra is an associative algebra that generalizes the sequence R, C, H, etc. Filtrations are increasing chains of subspaces that respect the structure of the object they are filtering. In this paper, we filter ideals in Clifford algebras. These filtrations must also satisfy a ā€œClifford conditionā€, making them compatible with the algebra structure. We define a notion of equivalence between these filtered ideals and proceed to analyze the space of equivalence classes. We focus our attention on a specific class of filtrations, which we call principal filtrations. Principal filtrations are described by a single element in complex projective space and their equivalence classes are orbits of a group action inside complex projective space. In this paper, we identify when the space of equivalence classes of principal filtrations has a discrete topology or not. We find one example where the space of equivalence classes is not discrete, and is instead homeomorphic to S^2

    A Quantum Random Walk Search Algorithm

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    Quantum random walks on graphs have been shown to display many interesting properties, including exponentially fast hitting times when compared with their classical counterparts. However, it is still unclear how to use these novel properties to gain an algorithmic speed-up over classical algorithms. In this paper, we present a quantum search algorithm based on the quantum random walk architecture that provides such a speed-up. It will be shown that this algorithm performs an oracle search on a database of NN items with O(N)O(\sqrt{N}) calls to the oracle, yielding a speed-up similar to other quantum search algorithms. It appears that the quantum random walk formulation has considerable flexibility, presenting interesting opportunities for development of other, possibly novel quantum algorithms.Comment: 13 pages, 3 figure

    Changes in invasive pneumococcal disease caused by streptococcus pneumoniae serotype 1 following introduction of pcv10 and pcv13 : Findings from the pserenade project

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    Funding Information: Funding: The PSERENADE project is funded by the Bill and Melinda Gates Foundation as part of the World Health Organization Pneumococcal Vaccines Technical Coordination Project, grant numā€ ber INVā€010429/OPP1189065. Funding Information: Conflicts of Interest: KH conducted the study and analyses while working at the Johns Hopkins School of Public Health but is an employee at Pfizer, Inc. as of 26 October 2020. MDK reports grants from Merck, personal fees from Merck, and grants from Pfizer, outside the submitted work. JCB reports funding from Pfizer in the past year, unrelated to the submitted work. JAS reports grants from the Bill & Melinda Gates Foundation, the Wellcome Trust, the UK MRC, National Institute of Health Research, outside the submitted work. MCB reports lectures fee from MSD outside from submitted work. AS reports grants and personal fees from Pfizer and personal fees from MSD and Sanofi Pasteur, outside the submitted work. ML has been a member of advisory boards and has received speakers honoraria from Pfizer and Merck. German pneumococcal surveillance has been supported by Pfizer and Merck. SD reports grant from Pfizer, outside the submitted work. KA reā€ ports a grant from Merck, outside the submitted work. AvG as received researching funding from Pfizer (last year 2017, Pfizer Investigatorā€Initiated Research [IIR] Program IIR WI 194379); attended advisory board meetings for Pfizer and Merck. CMA reports grants and personal fees from Pfizer, Qiagen and BioMerieux and grants from Genomica SAU, outside the submitted work. AMā€research support to my institution from Pfizer and Merck; honoraria for advisory board membership from GlaxoSmithKline, Merck and Pfizer. SNL performs contract research for GSK, Pfizer, Sanofi Pasteur on behalf of St. Georgeā€™s University of London, but receives no personal remuneration. IY stated she was a member of mRNAā€1273 study group and has received funding to her institution to conduct clinical research from BioFire, MedImmune, Regeneron, PaxVax, Pfizer, GSK, Merck, Novavax, Sanofiā€Pasteur, and Micron. RD has received grants/research support from Pfizer, Merck Sharp & Dohme and Medimmune; has been a scientific consultant for Pfizer, MeMed, Merck Sharp & Dohme, and Biondvax; had served on advisory boards of Pfizer, Merck Sharp & Dohme and Biondvax and has been a speaker for Pfizer. LLH reports research grants to her institution from GSK, Pfizer and Merck. JDK has received an unrestricted grantā€inā€aid from Pfizer Canada that supā€ ports, in part, the CASPER invasive pneumococcal disease surveillance project. MH received an educational grant from Pfizer AG for partial support of this project. However, Pfizer AG had no role in the data analysis and content of the manuscript. MC has previously received a professional fee from Pfizer (Ireland), an unrestricted research grant from Pfizer Ireland (2007ā€“2016) and an Inā€ vestigator Initiated Reward from Pfizer Ireland in 2018 (W1243730). CLB, MD has intellectual propā€ erty in BioFire Diagnostics and receives royalties through the University of Utah. CLB is an advisor to IDbyDNA. AK reports personal fees from Pfizer, outside the submitted work. MT reports grants from GlaxoSmithKline and grants from Pfizer Inc. to the Finnish Institute for Health and Welfare for research projects outside the submitted work, in which she has been a coā€investigator. JCS reā€ ports had received assistance from Pfizer for attending to scientific meetings outside the submitted work. SCGA received travel grant from Pfizer. BL had two research grants from Pfizer on Streptoā€ coccus pneumoniae. EV reports grants from French public health agency, during the conduct of the study; grants from Pfizer, grants from Merck, outside the submitted work. NBZ has received invesā€ tigatorā€initiated research grants from GlaxoSmithKline, Takeda Pharmaceuticals, Merck and the Seā€ rum Institute of India, all unrelated to this research. CGS reports grant funding from Pfizer, Merck, and AstraZeneca in the past 3 years. NMvS reports grants and fee for service from Pfizer, fee for service from MSD and GSK, outside the submitted work; In addition, NMvS has a patent WO 2013/020090 A3 with royalties paid to University of California San Diego (inventors: Nina van Sorge/Victor Nizet). All other authors did not declare any conflicts of interest. The funders had no Publisher Copyright: Ā© 2021 by the authors. Licensee MDPI, Basel, Switzerland.Streptococcus pneumoniae serotype 1 (ST1) was an important cause of invasive pneumococ-cal disease (IPD) globally before the introduction of pneumococcal conjugate vaccines (PCVs) con-taining ST1 antigen. The Pneumococcal Serotype Replacement and Distribution Estimation (PSEREā€ NADE) project gathered ST1 IPD surveillance data from sites globally and aimed to estimate PCV10/13 impact on ST1 IPD incidence. We estimated ST1 IPD incidence rate ratios (IRRs) compar-ing the preā€PCV10/13 period to each postā€PCV10/13 year by site using a Bayesian multiā€level, mixed-effects Poisson regression and allā€site IRRs using a linear mixedā€effects regression (N = 45 sites). Following PCV10/13 introduction, the incidence rate (IR) of ST1 IPD declined among all ages. After six years of PCV10/13 use, the allā€site IRR was 0.05 (95% credibility interval 0.04ā€“0.06) for all ages, 0.05 (0.04ā€“0.05) for <5 years of age, 0.08 (0.06ā€“0.09) for 5ā€“17 years, 0.06 (0.05ā€“0.08) for 18ā€“49 years, 0.06 (0.05ā€“0.07) for 50ā€“64 years, and 0.05 (0.04ā€“0.06) for ā‰„65 years. PCV10/13 use in infant immunization programs was followed by a 95% reduction in ST1 IPD in all ages after approximately 6 years. Limited data availability from the highest ST1 disease burden countries using a 3+0 schedule constrains generalizability and data from these settings are needed.publishersversionPeer reviewe

    The hustle and bustle of city life : monitoring the effects of urbanisation in the African lesser bushbaby

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    Urbanisation has become a severe threat to pristine natural areas, causing habitat loss and affecting indigenous animals. Species occurring within an urban fragmented landscape must cope with changes in vegetation type as well as high degrees of anthropogenic disturbance, both of which are possible key mechanisms contributing to behavioural changes and perceived stressors. We attempted to elucidate the effects of urbanisation on the African lesser bushbaby, Galago moholi, by (1) recording activity budgets and body condition (body mass index, BMI) of individuals of urban and rural populations and (2) further determining adrenocortical activity in both populations as a measure of stress via faecal glucocorticoid metabolite (fGCM) levels, following successful validation of an appropriate enzyme immunoassay test system (adrenocorticotropic hormone (ACTH) challenge test). We found that both sexes of the urban population had significantly higher BMIs than their rural counterparts, while urban females had significantly higher fGCM concentrations than rural females. While individuals in the urban population fed mainly on provisioned anthropogenic food sources and spent comparatively more time resting and engaging in aggressive interactions, rural individuals fed almost exclusively on tree exudates and spent more time moving between food sources. Although interactions with humans are likely to be lower in nocturnal than in diurnal species, our findings show that the impact of urbanisation on nocturnal species is still considerable, affecting a range of ecological and physiological aspects.Deutsche Forschungsgemeinschaft (DFG; DA 1031/3-1/2) and the DST-NRF SarchI Chair of Mammal Behavioural Ecology and Physiology.http://link.springer.com/journal/1142016-10-31hb201

    Spicing up the menu : evidence of fruit feeding in Galago moholi

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    The African lesser bushbaby, Galago moholi, is currently described as a food specialist, feeding exclusively on small arthropods and gum primarily from Acacia karroo trees. We studied a population of G. moholi in a highly-fragmented habitat in the southernmost part of its natural distributional range in South Africa. In this habitat we opportunistically observed bushbabies feeding on fruits of the winter fruiting tree, Pappea capensis. Plot counts of tree composition revealed that although the dominant tree species in the area belonged to the genus Acacia, A. karroo trees were widely absent and gum could only be found in small quantities on other Acacia species. The analysis of P. capensis fruits showed high levels of protein, fat and energy content, making the fruits a potentially important food source for G. moholi during winter when insect availability is low. Our observation is the first documented case of fruit-feeding in G. moholi, suggesting that the species is not a food specialist as previously reported, but can opportunistically supplement its diet with fruit when available.Deutsche Forschungsgemeinschaft (DFG; DA 1031/3-1), the Department of Research and Innovation (University of Pretoria) and the DST-NRF SarchI Chair of Mammal Behavioural Ecology and Physiology.http://link.springer.com/journal/10329hb201

    Female reproductive activity and its endocrine correlates in the African lesser bushbaby, Galago moholi

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    Steroid hormones play an important role in female reproductive physiology and behaviour and are often used to monitor important female reproductive events. However, such studies are often attempted on captive populations alone, delivering limited data. One such example is the African lesser bushbaby, Galago moholi, for which contradicting observational data exist between captive and free-ranging populations, while hormonal analyses have only been obtained from a single captive population. To extend and rectify the limited information, we monitored faecal progestagen and oestrogen metabolite levels across various important life history stages of both captive and free-ranging G. moholi. We additionally recorded changes in vaginal state as well as the occurrence of reproductive and aggressive behaviour throughout the study. Data from our captive population revealed an ovarian cycle length of 33.44 Ā± 0.59 days (mean Ā± SD), with follicular and luteal phases of 14.2 Ā± 1.0 and 19.1 Ā± 1.5 days, respectively, and an average pregnancy length of 128 Ā± 3.3 days. The initiation of female reproductive activity was closely linked to an oestrus-related increase in faecal oestrogen metabolite levels. Four of the seven captive females monitored in our study conceived during the May mating period, with one additional female fertilised in September, supporting the idea that the September mating period functions as a back-up for female G. moholi. Identified benchmark faecal progestagen metabolite levels (non-pregnant: >1 Ī¼g/g dry weight (DW), pregnant: >9 Ī¼g/g DW) should help researchers to determine pregnancy status of randomly wild-caught females in even a cross-sectional study setup.Deutsche Forschungsgemeinschaft (DFG; DA 1031/3-1/2) and the DST-NRF SarchI Chair of Mammal Behavioural Ecology and Physiology.http://link.springer.com/journal/3602017-02-28hb201

    Comparative gastrointestinal morphology of three small mammalian insectivores : Acomys spinosissimus (Rodentia), Crocidura cyanea (Eulipotyphla), and Amblysomus hottentotus (Afrosoricida)

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    The gastrointestinal morphology was investigated in three mammalian insectivorous species, namely Acomys spinosissimus, Crocidura cyanea, and Amblysomus hottentotus. The aim of the study was to provide a comprehensive morphological comparison between the different species and to explore whether anatomical gastrointestinal adaptations are associated with the insectivorous diet of these species. The shape, proportional length, and proportional surface areas of the different gastrointestinal regions were recorded and compared in the three insectivores. Hematoxylin and Eosin (H&E) and Alcian Blue/Periodic Acid Schiff (AB/PAS) were used for morphological assessment. In all three species, the stomach was simple and uncompartmentalized. The internal aspect of the stomach in A. spinosissimus was hemi-glandular, containing stratified squamous epithelium in the fundus, with glandular epithelium in the body and pyloric region. However, C. cyanea and A. hottentotus had wholly glandular stomachs. Paneth cells were not observed in the intestinal tracts of C. cyanea and A. hottentotus. Acomys spinosissimus was the only species studied that had a cecum. The proximal colonic region of A. spinosissimus had V-shaped mucosal folds. Histologically, C. cyanea had villi throughout the entire gastrointestinal tract (GIT), whereas for A. hottentotus villi were not present in the most distal gastrointestinal regions. In both C. cyanea and A. hottentotus, longitudinal mucosal folds were present in the distal part of the colon. The GITs of C. cyanea and A. hottentotus showed little morphological differentiation namely, a simple, glandular stomach and the lack of a cecum.http://www.interscience.wiley.com/journal/35280/homehb201

    Sometimes you have to take the person and show them how : adapting behavioral activation for peer recovery specialist-delivery to improve methadone treatment retention

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    BACKGROUND: Despite efficacy of medication for opioid use disorder, low-income, ethno-racial minoritized populations often experience poor opioid use disorder treatment outcomes. Peer recovery specialists, individuals with lived experience of substance use and recovery, are well-positioned to engage hard-to-reach patients in treatment for opioid use disorder. Traditionally, peer recovery specialists have focused on bridging to care rather than delivering interventions. This study builds on research in other low-resource contexts that has explored peer delivery of evidence-based interventions, such as behavioral activation, to expand access to care. METHODS: We sought feedback on the feasibility and acceptability of a peer recovery specialist-delivered behavioral activation intervention supporting retention in methadone treatment by increasing positive reinforcement. We recruited patients and staff at a community-based methadone treatment center and peer recovery specialist working across Baltimore City, Maryland, USA. Semi-structured interviews and focus groups inquired about the feasibility and acceptability of behavioral activation, recommendations for adaptation, and acceptability of working with a peer alongside methadone treatment. RESULTS: Participants (N = 32) shared that peer recovery specialist-delivered behavioral activation could be feasible and acceptable with adaptations. They described common challenges associated with unstructured time, for which behavioral activation could be particularly relevant. Participants provided examples of how a peer-delivered intervention could fit well in the context of methadone treatment, emphasizing the importance of flexibility and specific peer qualities. CONCLUSIONS: Improving medication for opioid use disorder outcomes is a national priority that must be met with cost-effective, sustainable strategies to support individuals in treatment. Findings will guide adaptation of a peer recovery specialist-delivered behavioral activation intervention to improve methadone treatment retention for underserved, ethno-racial minoritized individuals living with opioid use disorder

    Variation in the Neisseria lactamica porin, and its relationship to meningococcal PorB

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    One potential vaccine strategy in the fight against meningococcal disease involves the exploitation of outer-membrane components of Neisseria lactamica, a commensal bacterium closely related to the meningococcus, Neisseria meningitidis. Although N. lactamica shares many surface structures with the meningococcus, little is known about the antigenic diversity of this commensal bacterium or the antigenic relationships between N. lactamica and N. meningitidis. Here, the N. lactamica porin protein (Por) was examined and compared to the related PorB antigens of N. meningitidis, to investigate potential involvement in anti-meningococcal immunity. Relationships among porin sequences were determined using distance-based methods and FST, and maximum-likelihood analyses were used to compare the selection pressures acting on the encoded proteins. These analyses demonstrated that the N. lactamica porin was less diverse than meningococcal PorB and although it was subject to positive selection, this was not as strong as the positive selection pressures acting on the meningococcal porin. In addition, the N. lactamica porin gene sequences and the protein sequences of the loop regions predicted to be exposed to the human immune system were dissimilar to the corresponding sequences in the meningococcus. This suggests that N. lactamica Por, contrary to previous suggestions, may have limited involvement in the development of natural immunity to meningococcal disease and might not be effective as a meningococcal vaccine component
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