检索结果-南通市图书馆

Electronic and thermoelectric properties of YbMg_(2)X_(2)(X=P,As,Sb,Bi)zintl compounds by first-principles method

在线全文

学校读者我要写书评

暂无评论

Journal of rare Earths 2024年第1期42卷 147-154,I0006页

作者： Sajid Khan Dil Faraz Khan r.Neffati Tariq Usman Muhammad Waqar Ahsraf Shamim Khan Saeed Ullah jan G.Murtaza Department of Physics University of Science&Technology BannuBannu28100Pakistan Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Laboratoire de Physique de La Matiere Condensee Departement de PhysiqueFaculte des Sciences de TunisUniversite Tunis El ManarCampus Universitaire1060TunisTunisia Department of Physics Shaoxing UniversityShaoxing312000China Department of Mathematics&Natural Sciences Prince Mohammad Bin Fahd UniversityAlkhobar31952Saudi Arabia Materials Modeling Lab Department of PhysicsIslamia College Peshawar25120KhyberPakhtunkhwaPakistan

In this work the structural,electronic and thermoelectric properties of YbMg_(2)X_(2)(X=P,As,Sb,Bi)zintl compounds were investigated comprehensively using first principles *** electronic properties were studied using PBE GGA,TB-mBJ and hybrid(YS-PBE0)*** the structural parameters of optimized structures are in harmonious agreement to the available *** band structure study illustrates that the titled materials manifest metallic and semi metallic nature using PBE and TB-mBJ potentials while they show wide band gap semiconducting behavior by following hybrid(YS-PBE0)*** density of states(TDOS)and partial density of states(PDOS)were also calculated to glimpse the contribution of orbitals of atoms in the formation of *** properties were studied by using BoltzTraP2 code employed to *** get enormous values of Seebeck coefficient(S),power factor(PF)and thermoelectric figure of merit(ZT)for all the samples YbMg_(2)X_(2)(X=P,As,Sb,Bi),Moreover,the overwhelming transport properties for the titled compounds indicate the optimum level of carriers’concentration which pinpoints these materials to be better thermoelectrics in the 1-2-2 zintl family.

关键词： Zintl compounds Hybrid functional Band structure Thermoelectrics rare earths

Postbiotics from Saccharomyces cerevisiae fermentation stabilize microbiota in rumen liquid digesta during grain-based subacute ruminal acidosis(SArA) in lactating dairy cows

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第5期15卷 2059-2080页

作者： Junfei Guo Zhengxiao Zhang Le Luo Guan Ilkyu Yoon jan C.Plaizier Ehsan Khafipour Department of Animal Science University of ManitobaWinnipegMB R3T 2N2Canada Present Address:College of Food and Biological Engineering Jimei UniversityXiamenFujian 361021China Department of Agriculture Food and Nutrition DepartmentUniversity of AlbertaEdmontonAB T6G 2R3Canada Faculty of Land and Food Systems University of British ColumbiaVancouverBC V6T 1Z4Canada Diamond V Cedar RapidsIA 52404United States Present Address:Cargill Animal Nutrition 15407 McGinty Road WestWayzataMN 55391USA

Background Subacute ruminal acidosis(SArA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host *** study evaluated the impact of two postbiotics from Saccharomyces cerevisiae fermentation products(SCFP)on rumen liquid associated microbiota of lactating dairy cows subjected to repeated grain-based SArA challenges.A total of 32 rumen cannulated cows were randomly assigned to 4 treatments from 4 weeks before until 12 weeks after *** groups included a Control diet or diets supplemented with postbiotics(SCFPa,14 g/d Original XPC;SCFPb-1X,19 g/d Nutri Tek;SCFPb-2X,38 g/d Nutri Tek,Diamond V,Cedar rapids,IA,USA).Grain-based SArA challenges were conducted during week 5(SArA1)and week 8(SArA2)after parturition by replacing 20%DM of the base total mixed ration(TMr)with pellets containing 50%ground barley and 50%ground *** DNA from rumen liquid samples was subjected to V3–V416S r rNA gene amplicon *** of rumen microbiota were compared among treatments and SArA *** Both SArA challenges reduced the diversity and richness of rumen liquid microbiota,altered the overall composition(β-diversity),and its predicted functionality including carbohydrates and amino acids metabolic *** SArA challenges also reduced the number of significant associations among different taxa,number of hub taxa and their composition in the microbial co-occurrence *** with SCFP postbiotics,in particular SCFPb-2X,enhanced the robustness of the rumen *** SCFP supplemented cows had less fluctuation in relative abundances of community members when exposed to SArA *** SCFP supplementation promoted the populations of lactate utilizing and fibrolytic bacteria,including members of ruminococcaceae and Lachnospiraceae,and also increased the numbers of hub taxa during non-SArA and SArA *** with S

关键词： Postbiotics rumen microbiota Saccharomyces cerevisiae fermentation products SArA

Ashtekar-Kodama Gravity as a Classical and Quantum Extension of Loop Quantum Gravity

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Physics 2024年第6期15卷 864-937页

作者： jan Helm Department of Electrical Engineering Technical University of Berlin Berlin Germany

This paper presents a new theory of gravity, called here Ashtekar-Kodama (AK) gravity, which is based on the Ashtekar-Kodama formulation of loop quantum gravity (LQG), yields in the limit the Einstein equations, and in the quantum regime a full renormalizable quantum gauge field theory. The three fundamental constraints (hamiltonian, gaussian and diffeomorphism) were formulated in 3-dimensional spatial form within LQG in Ashtekar formulation using the notion of the Kodama state with positive cosmological constant Λ. We introduce a 4-dimensional covariant version of the 3-dimensional (spatial) hamiltonian, gaussian and diffeomorphism constraints of LQG. We obtain 32 partial differential equations for the 16 variables Emn (E-tensor, inverse densitized tetrad of the metric) and 16 variables Amn (A-tensor, gravitational wave tensor). We impose the boundary condition: for large distance the E-generated metric g(E) becomes the Gr-metric g (normally Schwarzschild-spacetime). The theory based on these Ashtekar-Kodama (AK) equations, and called in the following Ashtekar-Kodama (AK-) gravity has the following properties. • For Λ = 0 the AK equations become Einstein equations, A-tensor is trivial (constant), and the E-generated metric g(E) is identical with the Gr-metric g. • When the AK-equations are developed into a Λ-power series, the Λ-term yields a gravitational wave equation, which has only at least quadrupole wave solutions and becomes in the limit of large distance r the (normal electromagnetic) wave equation. • AK-gravity, as opposed to Gr, has no singularity at the horizon: the singularity in the metric becomes a (very high) peak. • AK-gravity has a limit scale of the gravitational quantum region 39 μm, which emerges as the limit scale in the objective wave collapse theory of Gherardi-rimini-Weber. In the quantum region, the AK-gravity becomes a quantum gauge theory (AK quantum gravity) with the Lie group extended SU(2) = ε-tensor-group(four gen

关键词： Quantum Gravity Loop Quantum Gravity General relativity Gravitational Wave Gauge Field Theory Graviton Hamiltonian Constraint Gaussian Constraint Diffeomorphism Constraint

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

共情考试

科学新闻 2024年第4期 59-60页

作者： jan Philipp r?er 倪伟波德国维藤/黑尔德克大学

“哦，现在我明白了。”同事说，“这就是你在考试上这么努力的原因。”在与一位同事共进午餐时，我分享了自己多年前作为一名患有考试焦虑症的学生所经历的挣扎。她的话让我有点吃惊，但让我开始思考，为什么从7年前开始当教授以来，...

“哦，现在我明白了。”同事说，“这就是你在考试上这么努力的原因。”在与一位同事共进午餐时，我分享了自己多年前作为一名患有考试焦虑症的学生所经历的挣扎。她的话让我有点吃惊，但让我开始思考，为什么从7年前开始当教授以来，我一直把缓解学生考试前的紧张放在首位。我意识到她可能是有道理的：作为学生的经历有助于我理解作为一名教授能做些什么让口试尽可能透明、公平和包容。这需要一些额外的工作，但是值得。

关键词：

Assessment of the effectiveness of weight-adjusted antibiotic administration,for reduced duration,in surgical prophylaxis of primary hip and knee arthroplasty

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Orthopedics 2024年第2期15卷 170-179页

作者： Tosan Okoro Michael Wan Takura Darlington Mukabeta Ella Malev Marketa Gross Claudia Williams Muhammad Manjra jan Herman Kuiper John Murnaghan Department of Arthroplasty Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation TrustOswestry SY107AGUnited Kingdom School of Medicine Keele UniversityStaffordshire ST55BGUnited Kingdom St Joseph’s Health Centre Unity Health TorontoToronto M6R 1B5Canada Department of Arthroplasty The Royal London HospitalBarts Health NHS TrustLondon E11BBUnited Kingdom Department of Arthroplasty Sunnybrook Holland Orthopaedic and Arthritis CentreToronto M4Y 1H1Canada Institute for Science and Technology in Medicine Keele UniversityStaffordshire ST51BGUnited Kingdom

BACKGrOUND Prophylactic antibiotics have significantly led to a reduction in the risk of postoperative surgical site infections(SSI)in orthopaedic *** aim of using antibiotics for this purpose is to achieve serum and tissue drug levels that exceed,for the duration of the operation,the minimum inhibitory concentration of the likely organisms that are *** antibiotics reduce the rate of SSIs in lower limb arthroplasty from between 4%and 8%to between 1%and 3%.Controversy,however,still surrounds the optimal frequency and dosing of antibiotic *** To evaluate the impact of introduction of a weight-adjusted antibiotic prophylaxis regime,combined with a reduction in the duration of administration of post-operative antibiotics on SSI incidence during the 2 years following primary elective total hip and knee arthroplasty METHODS Following ethical approval,patients undergoing primary total hip arthroplasty(THA)/total knee arthroplasty(TKA)with the old regime(Or)of a preoperative dose[cefazolin 2 g intravenously(IV)],and two subsequent doses(2 h and 8 h),were compared to those after a change to a new regime(Nr)of a weight-adjusted preoperative dose(cefazolin 2 g IV for patientsr patients>120 kg)and a post-operative dose at 2 *** primary outcome in both groups was SSI rates during the 2 years *** A total of n=1273 operations(THA n=534,TKA n=739)were performed in n=1264 *** was no statistically significant difference in the rate of deep(Or 0.74%(5/675)vs Nr 0.50%(3/598);fishers exact test P=0.72),nor superficial SSIs(Or 2.07%(14/675)vs Nr 1.50%(9/598);chi-squared test P=0.44)at 2 years *** propensity score weighting and an interrupted time series analysis,there was also no difference in SSI rates between both groups[rr 0.88(95%CI 0.61 to 1.30)P=0.46].CONCLUSION A weight-adjusted regime,with a reduction in number of post-operative doses had no adverse impact on S

关键词： Antibiotics Weight-adjusted Hip and knee arthroplasty Surgical site infection

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

具有半子模式欧拉拓扑绝缘体的声学观测

Science Bulletin 2024年第11期69卷 1653-1659页

作者：姜斌 Adrien Bouhon 吴世巧孔泽霖林志康 robert-jan Slager 蒋建华 Suzhou Institute for Advanced research University of Science and Technology of ChinaSuzhou 215123China School of Physical Science and Technology&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China TCM Group Cavendish LaboratoryUniversity of CambridgeCambridge CB30HEUK NOrDITA Stockholm University and KTH Royal Institute of TechnologyStockholm SE-10691Sweden

Topological band theory has conventionally been concerned with the topology of bands around a single gap. Only recently non-Abelian topologies that thrive on involving multiple gaps were studied, unveiling a new horizon in topological physics beyond the conventional paradigm. Here, we report on the first experimental realization of a topological Euler insulator phase with unique meronic characterization in an acoustic metamaterial. We demonstrate that this topological phase has several nontrivial features:First, the system cannot be described by conventional topological band theory, but has a nontrivial Euler class that captures the unconventional geometry of the Bloch bands in the Brillouin ***, we uncover in theory and probe in experiments a meronic configuration of the bulk Bloch states for the first time. Third, using a detailed symmetry analysis, we show that the topological Euler insulator evolves from a non-Abelian topological semimetal phase via. the annihilation of Dirac points in pairs in one of the band gaps. With these nontrivial properties, we establish concretely an unconventional bulk-edge correspondence which is confirmed by directly measuring the edge states via. pump-probe techniques. Our work thus unveils a nontrivial topological Euler insulator phase with a unique meronic pattern and paves the way as a platform for non-Abelian topological phenomena.

关键词： Euler insulators Meronic waves Acoustic metamaterials Topological phases of matter

Diagnostic delay in inflammatory bowel diseases in a German population

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第29期30卷 3465-3478页

作者： Elisabeth Blüthner Annalena Dehe Carsten Büning Britta Siegmund Matthias Prager Jochen Maul Alexander Krannich jan Preiß Bertram Wiedenmann Florian rieder raneem Khedraki Frank Tacke Andreas Sturm Anja Schirbel Department of Hepatology and Gastroenterology Campus Virchow-Klinikum and Campus CharitéMitteCharité-Universitätsmedizin BerlinBerlin 10117Germany Department of Gastroenterology Vivantes Klinikum im FriedrichshainBerlin 10249Germany Department of Internal Medicine Krankenhaus WaldfriedeBerlin 14163Germany Department of Gastroenterology Infectious Diseases and RheumatologyCharité-Universitätsmedizin BerlinBerlin 12203Germany Praxis für Gastroenterologie Berlin Zehlendorf Berlin 14195Germany Gastroenterologie am Bayrischen Platz Berlin 10825Germany Clinical Trial Office Charité-Universitätsmedizin BerlinBerlin 10117Germany Department of Gastroenterology Diabetology and HepatologyVivantes Klinikum NeuköllnBerlin 10117Germany Department of Gastroenterology Hepatology and NutritionDigestive Diseases and Surgery InstituteThe Cleveland Clinic FoundationClevelandOH 44195United States Department of Internal Medicine DRK Kliniken Berlin WestendBerlin 14050Germany Gastroenterologie im Havelland Straße der EinheitFalkensee 14612Germany

BACKGrOUND Early diagnosis is key to prevent bowel damage in inflammatory bowel disease(IBD).risk factor analyses linked with delayed diagnosis in European IBD patients are scarce and no data in German IBD patients *** To identify risk factors leading to prolonged diagnostic time in a German IBD *** Between 2012 and 2022,430 IBD patients from four Berlin hospitals were enrolled in a prospective study and asked to complete a 16-item questionnaire to determine features of the path leading to IBD *** diagnostic time was defined as the time from symptom onset to consulting a physician(patient waiting time)and from first consultation to IBD diagnosis(physician diagnostic time).Univariate and multivariate analyses were performed to identify risk factors for each time *** The total diagnostic time was significantly longer in Crohn’s disease(CD)compared to ulcerative colitis(UC)patients(12.0 vs 4.0 mo;Preased physician diagnostic time(5.5 vs 1.0 mo;Priate analysis,the predominant symptoms diarrhea(P=0.012)and skin lesions(P=0.028)as well as performed gastroscopy(P=0.042)were associated with longer physician diagnostic time in CD *** UC,fever was correlated(P=0.020)with shorter physician diagnostic time,while fatigue(P=0.011)and positive family history(P=0.046)were correlated with longer physician diagnostic *** We demonstrated that CD patients compared to UC are at risk of long diagnostic *** efforts should focus on shortening the diagnostic delay for a better outcome in these patients.

关键词： Diagnostic time Diagnostic delay Crohn’s disease Ulcerative colitis Germany

Outlier detection by means of robust regression estimators for use in engineering science

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 909-921页

作者： Serif HEKIMOGLU r. Cuneyt ErENOGLU jan KALINA Department of Geodesy and Photogrammetry Engineering Yildiz Technical University Department of Probability and Mathematical Statistics Charles University

This study compares the ability of different robust regression estimators to detect and classify outliers. Well-known estimators with high breakdown points were compared using simulated data. Mean success rates (MSr) were computed and used as comparison criteria. The results showed that the least median of squares (LMS) and least trimmed squares (LTS) were the most successful methods for data that included leverage points, masking and swamping effects or critical and concentrated outliers. We recommend using LMS and LTS as diagnostic tools to classify outliers, because they remain robust even when applied to models that are heavily contaminated or that have a complicated structure of outliers.

关键词： Linear regression Outlier Mean success rate (MSr) Leverage point Least median of squares (LMS) Least trimmedsquares (LTS)

Alloying effect of silver in magnesium on the development of microstructure and mechanical properties by indirect extrusion

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2021年第1期9卷 112-122页

作者： Bjorn Wiese regine Willumeit-römer Dietmar Letzig jan Bohlen Division Metallic Biomaterials Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck-Str.1Geesthacht 21502Germany Magnesium Innovation Center(MagIC) Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck-Str.1Geesthacht 21502Germany

The effect of Ag in solid solution on the microstructure,texture and the deformation behaviour of indirectly extruded Mg was *** as a solid solution strengthener affects the behaviour during extrusion,resulting in enhanced deformation related heating and corresponding coarser grained *** substantial effect on the texture development is *** mechanical properties simultaneously increase in stress and strain levels with increasing Ag content,especially in tension as a result of the changing impact of the slip modes which can be associated with a decrease of the lattice parameters as well as the c/a ratio of the hcp lattice *** compression tests with twin dominated flow,the impact is much smaller on the compressive yield stress but higher with respect to the twinning related strain hardening *** solution strength functions for Fleischer and Labusch were determined,also confirming the anisotropic behaviour of the extruded Mg alloys.

关键词： Mg-Ag-alloys Lattice parameters Indirect extrusion Microstructure Mechanical properties