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Nearest Neighbor Sampling of Point Sets Using Rays

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1131-1174页

作者： Liangchen Liu Louis Ly Colin B.Macdonald richard Tsai Department of Mathematics The University of Texas at Austin2515 SpeedwayAustinTX 78712USA Oden Institute for Computational engineering and Sciences The University of Texas at Austin201 E24th StAustinTX 78712USA Department of Mathematics University of British Columbia1984 Mathematics RdVancouverBCV6T1Z2Canada

We propose a new framework for the sampling,compression,and analysis of distributions of point sets and other geometric objects embedded in euclidean *** approach involves constructing a tensor called the RaySense sketch,which captures nearest neighbors from the underlying geometry of points along a set of *** explore various operations that can be performed on the RaySense sketch,leading to different properties and potential *** information about the data set can be extracted from the sketch,independent of the ray *** integrals on point sets can be efficiently computed using the *** also present several examples illustrating applications of the proposed strategy in practical scenarios.

关键词： Point clouds Sampling Classification Registration Deep learning Voronoi cell analysis

Wildfire severity alters soil microbial exoenzyme production and fungal abundances in the southern Appalachian Mountains

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Pedosphere 2024年第5期34卷 865-878页

作者： Megan L.SCHILL richard BAIRD Shawn P.BROWN Allison M.VeACH Department of Integrative Biology University of Texas at San Antonio Biochemistry Molecular Biology Entomology and Plant Pathology Department Mississippi State University Department of Biological Sciences The University of Memphis

Climate change has increased drought frequency and duration that are exacerbated by increased temperatures globally. This effect has, and will continue,to increase fire occurrence across many regions of North America. In the southern Appalachian Mountains, wildfires with high burn severity occurred in 2016due to increased drought and human activity. To investigate the effects of burn severity on soil physicochemical properties, microbial extracellular enzyme production, and microbial abundances in a temperate region, surface soils (0–15 cm) were collected from two sites (the Great Smoky Mountains National Park in Tennessee and the Nantahala National Forest in North Carolina, USA) spanning lightly, moderately, and severely burned areas, accompanied by adjacent unburned locations that act as controls. The soil samples were collected at three time points between 2017 and 2019 (i.e., 0.5, 1, and 2.5 years post-fire)among burn severity plots. Total hydrolytic enzyme production varied over time, with severe burn plots having significantly lower enzyme production at 2.5years post-fire. Individual enzymes varied among burn severities and across time post-fire. Light burn plots showed greater carbon-specific (β-glucosidase and β-xylosidase) and phosphorus-specific (acid phosphatase) enzyme activities at 0.5 years post-fire, but this effect was transient. At 2.5 years post-fire, theβ-xylosidase and acid phosphatase activities were lower in severe or moderate burn plots relative to the controls. In contrast, the activity of nitrogen-specific enzyme leucyl aminopeptidase was the lowest in severe burn plots at 0.5 years post-fire, but was the lowest in light burn plots at 2.5 years post-fire. The fungi:bacteria ratio declined with burn severity, indicating that fungi are sensitive or less resilient to high burn severity during recovery. These results suggest that wildfires alter trajectories for soil microbial structure and function within a 2.5-year timeframe, which potentially

关键词： 16S rRNA burn severity extracellular enzyme fungi:bacteria ratio internal transcribed spacer microbial structure

A hybrid Monte Carlo study of bond-stretching electron–phonon interactions and charge order in BaBiO_(3)

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npj Computational Materials 2023年第1期9卷 1950-1958页

作者： Benjamin Cohen-stead Kipton Barros richard Scalettar Steven Johnston Department of Physics and Astronomy The University of TennesseeKnoxvilleTN 37996USA Institute for Advanced Materials and Manufacturing The University of TennesseeKnoxvilleTN 37996USA Theoretical Division and CNLS Los Alamos National LaboratoryLos AlamosNM 87545USA Department of Physics and Astronomy University of CaliforniaDavisCA 95616USA

The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains *** address this question using nonperturbative hybrid Monte Carlo calculations for the parent compound BaBiO_(3).Our model includes the Bi 6s and O 2pσorbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping *** simulate three-dimensional clusters of up to 4000 orbitals,with input model parameters taken from ab initio electronic structure calculations and a phonon energyℏΩ0=60 *** results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system,despite a relatively small dimensionless *** also find that the transition deviates from the weak-coupling Peierls’*** work demonstrates that off-diagonal e-ph interactions in orbital space are vital in establishing the bismuthate phase diagram.

关键词： stretching phonon charge

Carbon dioxide enrichment affected flower numbers transiently and increased successful post-pollination development stably but without altering final acorn production in mature pedunculate oak (Quercus robur L.)

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Journal of Forestry Research 2024年第4期35卷 1-12页

作者： Ryan McClory richard H.ellis Martin Lukac Jo Clark Carolina Mayoral Kris M.Hart Andrew R.G.Plackett A.Rob MacKenzie School of Agriculture Policy and DevelopmentUniversity of ReadingAgricultureEarley GateWhiteknights RoadPO Box 237Reading RG66EUUK Faculty of Forestry and Wood Sciences Czech University of Life Sciences PraguePrague 165000Czechia Future Trees Trust Harwell Innovation CentreBuilding 173Curie AvenueHarwellOxford OX110QGUK Birmingham Institute of Forest Research University of BirminghamEdgbastonBirmingham B152TTUK School of Biosciences University of BirminghamEdgbastonBirmingham B152TTUK School of Geography Earth and Environmental SciencesUniversity of BirminghamEdgbastonBirmingham B152TTUK

Acorn production in oak(Quercus spp.)shows considerable inter-annual variation,known as masting,which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each *** emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the‘fertilisation effect’that leads to enhanced *** examine if acorn production in mature woodland communities will be affected by further increase in CO_(2),the contents of litter traps from a Free Air Carbon enrichment(FACe)experiment in deciduous woodland in central england were analysed for numbers of flowers and acorns of pedunculate oak(Quercus robur L.)at different stages of development and their predation levels under ambient and elevated CO_(2) ***-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021,with the greatest numbers of mature acorns in 2015,2017 and 2020 but almost none in *** numbers of flowers,enlarged cups,immature acorns,empty acorn cups,and galls in the litter traps also varied amongst years;comparatively high numbers of enlarged cups were recorded in 2018,suggesting *** at this site is a fruit maturation masting species(i.e.,the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly).Raising the atmospheric CO_(2) concentration by 150μL L^(−1),from early 2017,increased the numbers of immature acorns,and all acorn evidence(empty cups+immature acorns+mature acorns)detected in the litter traps compared to ambient controls by 2021,but did not consistently affect the numbers of flowers,enlarged cups,empty cups,or mature *** number of flowers in the elevated CO_(2) plots’litter traps was greater in 2018 than 2017,one year after CO_(2) enrichment began,whereas numbers declined in ambient *** with CO_(2) also increased the number o

关键词： Quercus robur L. Acorns Masting Pedunculate oak Carbon dioxide

Contribution of CT Scanning in the Investigation of Cranioencephalic Lesions in Bangui

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Open Journal of Radiology 2024年第3期14卷 156-165页

作者： Bangue Songrou Francky Kouandongui Timothée Mobima Borel Tambala Yannick Héritier Sombot-Soule Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan richard Bazogo National Center of Medical Imaging of Bangui Bangui Central African Republic Maman elisabeth DOMITIeN Hospital Bangui Central African Republic Community Hospital of Bangui Bangui Central African Republic

Introduction: Cranioencephalic exploration has always played a major role in CT scans. In the Central Africa Republic (CAR), the lack of cross-sectional imaging before the year 2020 meant that no study had focused on cranioencephalic lesions. The aim of this study was to contribute to improving the management of cranioencephalic pathologies in CAR. Patients and Method: The study took place at the Bangui National Medical Imaging Centre (CNIMB). It was a retrospective study over a two-year period (March 1, 2021 to February 30, 2023). All patients referred for cranioencephalic CT scans were included, regardless of age or sex. Results: 1745 CT scans were performed, 575 of which were cranioencephalic CT scans. The majority of patients were male (53%). Most lived in the capital Bangui (90.9%). Patients aged 61 and over were the most representative. The distribution of patients by requesting department showed that the reception and emergency department was one of the least requesting departments. The main abnormalities observed were strokes, 82.1% of which were ischaemic strokes and 17.9% haemorrhagic strokes. Strokes were followed by degenerative lesions. Post-traumatic injuries included haemorrhagic contusions (38.3%), subdural haematomas in 20.5% of cases, and extradural haematomas (9.3%). Craniofacial lesions (fractures) were observed in 45.8% of cases. Conclusion: Cranioencephalic scans accounted for 1/3 of CT examinations performed during the study period. It revealed pathologies that could not be detected by conventional means. All in all, CT scans contributed to the diagnosis of cerebral pathologies.

关键词： Cranioencephalic Scan National Medical Imaging Centre Bangui

Contribution of CT in the exploration of Non-Traumatic Pathologies of the Lumbar Spine in Adults in Bangui

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Open Journal of Radiology 2024年第3期14卷 125-134页

作者： Bangue Songrou Francky Kouandongui Timothée Mobima Yannick Héritier Sombot Borel Tambala Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan richard Bazogo National Center of Medical Imaging of Bangui Bangui Central Africa Republic Maman elisabeth DOMITIeN Hospital Bangui Central Africa Republic Community Hospital of Bangui Bangui Central Africa Republic

Background: In Central African Republic, a study carried out in 2019 highlighted the limits of conventional radiography in the diagnosis of non-traumatic lower back pain in adults. Objective: The objective of this study is to show the value of CT scanning in the exploration of non-traumatic pathologies of the lumbar spine in adults. Patients and Method: Retrospective and descriptive cross-sectional study covering the files of patients aged at least 18 years old, sent for lumbar scanning from March 1 to December 31, 2021 at the medical imaging center. Results: In total, 593 scan examinations were performed including 159 (26.8%) examinations of the lumbar spine. The average age of the patients was 49.84 years. The majority were male (66%). 127 (79.8%) were referred mainly to the neurology and rheumatology departments. Common low back pain (n = 97, 61%) was the main reason for requesting a CT scan. The lumbar scan was performed without contrast product in 88.7% of cases. In total, 148 (93.1%) examinations were pathological and dominated by overall disc overhang (62.2%) and somatic and interapophyseal osteoarthritis (16.9%). The other lesions were spondylodiscitis (7.4%), tumor-like lesions (3.4%) and narrow lumbar canal (1.4%).

关键词： CT Scanning Lumbar Bangui Adults

New approaches to quantify progressive damage and associated dynamic rock mass blockiness

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Journal of Rock Mechanics and Geotechnical engineering 2023年第2期15卷 285-295页

作者： Ladan Karimi Sharif Davide elmo Doug stead NBK Institute of Mining engineering The University of British ColumbiaVancouverCanada Department of earth Science Simon Fraser UniversityBurnabyCanada

In the past decade, numerical modelling has been increasingly used for simulating the mechanical behaviour of naturally fractured rock masses. In this paper, we introduce new algorithms for spatial and temporal analyses of newly generated fractures and blocks using an integrated discrete fracture network (DFN)-finite-discrete element method (FDeM) (DFN-FDeM) modelling approach. A fracture line calculator and analysis technique (i.e. discrete element method (DeM) fracture analysis, DeMFA) calculates the geometrical aspects of induced fractures using a dilation criterion. The resultant two-dimensional (2D) blocks are then identified and characterised using a graph structure. Block tracking trees allow track of newly generated blocks across timesteps and to analyse progressive breakage of these blocks into smaller blocks. Fracture statistics (number and total length of initial and induced fractures) are then related to the block forming processes to investigate damage evolution. The combination of various proposed methodologies together across various stages of modelling processes provides new insights to investigate the dependency of structure's resistance on the initial fracture configuration.

关键词： Numerical modelling Spatial analysis Temporal analysis Discrete fracture network(DFN) Finite-discrete element method(FDeM)modelling Block calculations Graph structure

COVID-19 vaccination produces exercise-responsive SARS-CoV-2 specific T-cells regardless of infection history

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Journal of Sport and Health Science 2024年第1期13卷 99-107页

作者： Kyle A.Smith Tiffany M.Zúñiga Forrest L.Baker Helena Batatinha Charles R.Pedlar Shane C.Burgess Michael P.Gustafson emmanuel Katsanis richard J.Simpson School of Nutritional Sciences and Wellness The University of ArizonaTucsonAZ 85721USA Department of Pediatrics The University of ArizonaTucsonAZ 85724USA Faculty of Sport Allied Health and Performance ScienceSt.Mary's UniversityTwickenham TW14SXUK Institute of Sport exercise and Health University College LondonLondon WC1E 7HUUK Department of Animal and Comparative Biomedical Sciences The University of ArizonaTucsonAZ 85721USA The University of Arizona Cancer Center The University of ArizonaTucsonAZ 85719USA Laboratory Medicine and Pathology Mayo Clinic ArizonaPhoenixAZ 85054USA Department of Immunobiology The University of ArizonaTucsonAZ 85724USA Department of Medicine The University of ArizonaTucsonAZ 85724USA Department of Pathology The University of ArizonaTucsonAZ 85724USA

Background:The mobilization and redistribution of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)specific T-cells and neutralizing antibodies(nAbs)during exercise is purported to increase immune surveillance and protect against severe coronavirus disease 2019(COVID-19).We sought to determine if COVID-19 vaccination would elicit exercise-responsive SARS-CoV-2 T-cells and transiently alter nAb ***:eighteen healthy participants completed a 20-min bout of graded cycling exercise before and/or after receiving a COVID-19 *** major leukocyte subtypes were enumerated before,during,and after exercise by flow cytometry,and immune responses to SARS-CoV-2 were determined using whole blood peptide stimulation assays,T-cell receptor(TCR)-βsequencing,and SARS-CoV-2 nAb ***:COVID-19 vaccination had no effect on the mobilization or egress of major leukocyte subsets in response to intensity-controlled graded ***,non-infected participants had a significantly reduced mobilization of CD4+and CD8+naive T-cells,as well as CD4+central memory T-cells,after vaccination(synthetic immunity group);this was not seen after vaccination in those with prior SARS-CoV-2 infection(hybrid immunity group).Acute exercise after vaccination robustly mobilized SARS-CoV-2 specific T-cells to blood in an intensity-dependent *** groups mobilized T-cells that reacted to spike protein;however,only the hybrid immunity group mobilized T-cells that reacted to membrane and nucleocapsid *** increased significantly during exercise only in the hybrid immunity ***:These data indicate that acute exercise mobilizes SARS-CoV-2 specific T-cells that recognize spike protein and increases the redistribution of nAbs in individuals with hybrid immunity.

关键词： Anti-viral COVID-19 exercise immunology SARS-CoV-2 T-Cells Vaccine

Sinonasal Polyposis: About 60 Cases at Fann University Hospital Center, Senegal

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International Journal of Otolaryngology and Head & Neck Surgery 2024年第1期13卷 53-61页

作者： Mame Sanou Diouf Moustapha Ndiaye Ahmadou Dembele evelyne Siga Diom Ciré Ndiaye Amadou Thiam richard e. A. Deguenonvo Abdou Sy Malick Ndiaye Abdourahmane Tall Issa Cheikh Ndiaye Raymond Diouf HOGIP Hospital Center Dakar Senegal Fann University Hospital Center Dakar Senegal Ourossogui Hospital Center Matam Senegal La Paix Hospital Center Ziguinchor Senegal Children Hospital Center of Diamniadio Dakar Senegal

Introduction: Sinonasal polyposis (SNP) is a chronic inflammatory disease of the mucosa of the nasal cavities and facial sinuses. It is characterized by an oedematous, multifocal and bilateral degeneration of the nasosinus mucosa, which originates in the lateral masses of the ethmoid, where it causes the formation of smooth, gelatinous, translucent and pyriform polyp lesions. The objective of this study was to review epidemiological, clinical, paraclinical data and evaluate the results of endoscopic surgical treatment. Patients and Methods: This is a retrospective study on 60 patients followed at the eNT department of the Fann National University Hospital Center, from January 2010 to December 2015. All patients with sinonasal polyposis were included in the study. Results: The average age of our patients was 38 years and the sex ratio (M/F) was 0.8. In the patients’ histories, we found 18% asthma and 10% Widal’s disease. The average consultation time was 8.5 years. All patients had consulted for nasal obstruction;rhinorrhea was bilateral and found in 67.7% of cases, with olfactory disorders accounting for 50%. The CT scan performed in 58% of cases made it possible to specify the extent of the lesions;the involvement of the ethmoidal sinus was constant and extended to the other sinuses except in 2 cases. All patients had received medical treatment with local corticosteroids. endoscopic surgical treatment was initiated in 43% of cases after failure of corticosteroid-based medical treatment. The evolution under treatment marked by the reappearance of symptoms that increased each month. At one month postoperatively, all clinical symptomatology had improved with the exception of olfactory disorders, which persisted in 3 patients. At 12 months we noted 12 cases of reappearance of nasal obstruction. Conclusion: SNP is a disease of little known etiology. The diagnosis is almost always clinical. endoscopic surgery remains a recourse to medical treatment. For good local contro

关键词： Sinonasal Polyposis endonasal endoscopic Surgery CHNU Fann