314 research outputs found

    Infinite generation of non-cocompact lattices on right-angled buildings

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    Let \Gamma be a non-cocompact lattice on a locally finite regular right-angled building X. We prove that if \Gamma has a strict fundamental domain then \Gamma is not finitely generated. We use the separation properties of subcomplexes of X called tree-walls.Comment: 11 pages, one figure. v2: new example and references in the introduction. To appear in Algebr. Geom. To

    Surface quotients of hyperbolic buildings

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    Let I(p,v) be Bourdon's building, the unique simply-connected 2-complex such that all 2-cells are regular right-angled hyperbolic p-gons and the link at each vertex is the complete bipartite graph K(v,v). We investigate and mostly determine the set of triples (p,v,g) for which there exists a uniform lattice {\Gamma} in Aut(I(p,v)) such that {\Gamma}\I(p,v) is a compact orientable surface of genus g. Surprisingly, the existence of {\Gamma} depends upon the value of v. The remaining cases lead to open questions in tessellations of surfaces and in number theory. Our construction of {\Gamma}, together with a theorem of Haglund, implies that for p>=6, every uniform lattice in Aut(I) contains a surface subgroup. We use elementary group theory, combinatorics, algebraic topology, and number theory.Comment: 23 pages, 4 figures. Version 2 incorporates referee's suggestions including new Section 7 discussing relationships between our constructions, previous examples, and surface subgroups. To appear in Int. Math. Res. No

    The Archaeology and History of Alamo Plaza

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    In the Spring of 1975, the Center for Archaeological Research was approached by the Parks and Recreation Department of the City of San Antonio regarding possible archaeological and historical research at Alamo Plaza. The proposed investigations were in connection with the city\u27s plan to renovate the plaza, to coincide with the American Bicentennial. There were two major reasons for the Center\u27s involvement: (1) the architects desired to learn, as a part of the renovation plans, the precise locations of the south wall of the original Alamo (San Antonio de Valero) compound; (2) in order to aid in the planning of the renovation, it was necessary to determine if subsurface archaeological resources existed in Alamo Plaza. To achieve these goals, a contract was agreed upon between the City of San Antonio and the Center for Archaeological Research at The University of Texas at San Antonio. A State Antiquities Permit (No. 94) was secured and all investigations were conducted under the terms of that permit

    Phytochemicals Added to the Feed of Ovariectomized Adult Rats Increase Brown Adipose Activity

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    Background: Brown adipose tissue (BAT) uncouples respiration, using lipids as an energy source while dissipating heat. Increases in BAT activity are protective against obesity, thus compounds that increase BAT activation may help prevent weight gain. Resveratrol (R) increases BAT activity by upregulating thermogenic genes. As phytochemicals have synergistic properties, our research strategy has included investigation of the efficacy of relatively low concentrations of phytochemical blends on BAT activation. Methods: Previously, we showed that R combined with genistein (G) and quercetin (Q) reduced weight gain in aged ovariectomized (OVX) female rats. In the current study, OVX rats were fed diets containing doses of phytochemicals with vitamin D (diet 1: 1000 mg/kg G; diet 2: 500 mg/kg G, 200 mg/kg R, and 1000 mg/kg Q; diet 3: 1000 mg/kg G, 400 mg/kg R, and 2000 mg/kg Q). Results: After 16 weeks, rats in the high dose group had a significantly smaller scapular BAT depot compared to non-OVX controls (0.74 g v 0.92 g;

    Predicting postoperative troponin in patients undergoing elective hip or knee arthroplasty: A comparison of five cardiac risk prediction tools

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    BACKGROUND: Elderly patients undergoing hip or knee arthroplasty are at a risk for myocardial injury after noncardiac surgery (MINS). We evaluated the ability of five common cardiac risk scores, alone or combined with baseline high-sensitivity cardiac troponin I (hs-cTnI), in predicting MINS and postoperative day 2 (POD2) hs-cTnI levels in patients undergoing elective total hip or knee arthroplasty. METHODS: This study is ancillary to the Genetics-InFormatics Trial (GIFT) of Warfarin Therapy to Prevent Deep Venous Thrombosis, which enrolled patients 65 years and older undergoing elective total hip or knee arthroplasty. The five cardiac risk scores evaluated were the atherosclerotic cardiovascular disease calculator (ASCVD), the Framingham risk score (FRS), the American College of Surgeon\u27s National Surgical Quality Improvement Program (ACS-NSQIP) calculator, the revised cardiac risk index (RCRI), and the reconstructed RCRI (R-RCRI). RESULTS: None of the scores predicted MINS in women. Among men, the ASCVD ( CONCLUSION: In elderly patients undergoing elective hip or knee arthroplasty, several of the scores modestly predicted MINS in men and correlated with POD2 hs-cTnI

    Employee perceived effect of leadership training: comparing public and private organizations

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    This study reports on the effectiveness of a year-long field experiment involving training in transformational and transactional leadership in the public and private sectors. Using before and after training assessments by employees of several hundred Danish leaders, the analysis shows that transformational leadership training is associated with increases in behaviors linked to both transformational leadership and the use of verbal rewards, but only for public sector organizations. There is no impact in private sector organizations. Transactional leadership training appears to be equally effective in stimulating the use of pecuniary rewards in both public and private organizations

    Current- and wave- generated bedforms on mixed sand-clay intertidal flats : a new bedform phase diagram and implications for bed roughness and preservation potential

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    Funding: This work was supported by the United Kingdom’s Natural Environment Research Council (NERC) under Grant NE/I027223/1 (COHBED). JM, Julie Hope, and Daniel Parsons were partially funded by a Horizon 2020 European Research Council Consolidator Award (GEOSTICK, Grant 725955). The GEOSTICK project also kindly contributed the article processing fees. Andrew Manning’s contribution toward this research was partly supported by the National Science Foundation grants OCE-1924532 and OCE-1736668, TKI-MUSA project 11204950-000-ZKS-0002, and the HR Wallingford company research project FineScale (Grant Nos. ACK3013_62). DP received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (Grant reference HR09011) and contributing institutions.The effect of bedforms on frictional roughness felt by the overlying flow is crucial to the regional modelling of estuaries and coastal seas. Bedforms are also a key marker of palaeoenvironments. Experiments have shown that even modest biotic and abiotic cohesion in sand inhibits bedform formation, modifies bedform size, and slows bedform development, but this has rarely been tested in nature. The present study used a comprehensive dataset recorded over a complete spring–neap cycle on an intertidal flat to investigate bedform dynamics controlled by a wide range of wave and current conditions, including the effects of wave–current angle and bed cohesion. A detailed picture of different bedform types and their relationship to the flow, be they equilibrium, non-equilibrium, or relict, was produced, and captured in a phase diagram that integrates wave-dominated, current-dominated, and combined wave–current bedforms. This bedform phase diagram incorporates a substantially wider range of flow conditions than previous phase diagrams, including bedforms related to near-orthogonal wave–current angles, such as ladderback ripples. Comparison with laboratory-derived bedform phase diagrams indicates that washed-out ripples, lunate interference ripples and upper-stage plane beds replace the subaqueous dune field; such bedform distributions may be a key characteristic of intertidal flats. The field data also provide a means of predicting the dimensions of these bedforms, which can be transferred to other areas and grain sizes. We show that an equation for the prediction of equilibrium bedform size is sufficient to predict the roughness, even though the bedforms are highly variable in character and only in equilibrium with the flow for approximately half the time. Whilst the effect of cohesive clay is limited under more active spring conditions, clay does play a role in reducing the bedform dimensions under more quiescent neap conditions. We also investigated which combinations of waves, currents, and bed clay contents in the intertidal zone have the highest potential for bedform preservation in the geological record. This shows that combined wave–current bedforms have the lowest preservation potential and equilibrium current ripples have the highest preservation potential, even in the presence of moderate and storm waves. Hence, the absence of wave ripples and combined-flow bedforms and their primary stratification in sedimentary successions cannot be taken as evidence that waves were absent at the time of deposition.Publisher PDFPeer reviewe
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