1,897 research outputs found

    Low-cost 3D printed 1  nm resolution smartphone sensor-based spectrometer: instrument design and application in ultraviolet spectroscopy.

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    We report on the development of a low-cost spectrometer, based on off-the-shelf optical components, a 3D printed housing, and a modified Raspberry Pi camera module. With a bandwidth and spectral resolution of ≈60  nm and 1 nm, respectively, this device was designed for ultraviolet (UV) remote sensing of atmospheric sulphur dioxide (SO2), ≈310  nm. To the best of our knowledge, this is the first report of both a UV spectrometer and a nanometer resolution spectrometer based on smartphone sensor technology. The device performance was assessed and validated by measuring column amounts of SO2 within quartz cells with a differential optical absorption spectroscopy processing routine. This system could easily be reconfigured to cover other UV-visible-near-infrared spectral regions, as well as alternate spectral ranges and/or linewidths. Hence, our intention is also to highlight how this framework could be applied to build bespoke, low-cost, spectrometers for a range of scientific applications

    Quais sĂŁo os fatores de risco para readmissĂŁo em pacientes com ileostomia?

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    OBJETIVO: o objetivo deste estudo foi identificar os fatores de risco para readmissĂŁo em pacientes submetidos Ă  cirurgia colorretal. MÉTODOS: um banco de dados de avaliação da qualidade colorretal em um Ășnico centro foi consultado para pacientes submetidos Ă  procedimentos colorretais com ileostomia em 2009. A amostra foi dividida em readmitidos versus nĂŁo readmitidos. A readmissĂŁo foi definida como a admissĂŁo dentro dos primeiros 30 dias apĂłs o procedimento Ă­ndice. os grupos foram comparados em relação Ă  caracterĂ­sticas prĂ©, intra e pĂłs-operatĂłrias. A anĂĄlise multivariada foi realizada para identificar os fatores de risco para readmissĂŁo. RESULTADOS: a consulta identificou 496 pacientes, [267 (54%) do sexo masculino, idade mĂ©dia de 48 anos (VIQ: 34 -60)]. oitenta e trĂȘs (17%) foram readmitidos; 296 pacientes (60%) foram operados por doença inflamatĂłria intestinal, 89 (18%) por cĂąncer, 16 (3%) por doença diverticular e 95 (19%) devido a outro diagnĂłstico. os trĂȘs procedimentos mais comuns foram proctocolectomia total com anastomose anal e bolsa ileal (IPAA) em 103 pacientes (21%), colectomia total com ileostomia final em 117 (24%) e ressecçÔes do intestino delgado (incluindo a remoção de fĂ­stula enterocutĂąnea e excisĂŁo da bolsa em J) em 149 (30%). As seguintes variĂĄveis foram significativamente mais comuns em pacientes readmitidos: tabagismo atual (24 % vs. 14%, p = 0,02), TVP/EP pĂłs-operatĂłrio (10% vs. 4 %, p = 0,04), infecção da ferida cirĂșrgica (20 % vs. 10% p = 0,01), sepse (22% vs. 8%, p < 0,001) e infecção de ĂłrgĂŁo/espaço do sĂ­tio cirĂșrgico (IOSC) (35 % vs. 5%, p < 0,001). A infecção do IOSC pĂłs-operatĂłrio foi o Ășnico fator independente associado com a readmissĂŁo na anĂĄlise multivariada (p < 0,001). CONCLUSÃO: os cirurgiĂ”es colorretais devem estar alertas para IOSC diante de um paciente com ileostomia readmitido apĂłs um procedimento colorretal.PURPOSE: the aim of this study was to identify the risk factors for readmission among patients submitted to colorectal surgery. METHODS: a single-center colorectal quality-assessment database was queried for patients undergoing colorectal procedures with ileostomy during 2009. The sample was divided into readmitted vs. non-readmitted. Readmission was defined as admission within the first 30 days after the index procedure. Groups were compared by pre, intra and postoperative characteristics. A multivariate analysis was performed to identify the risk factors for readmission. RESULTS: the query returned 496 patients, [267 (54%) males, median age 48 years (IQR: 34-60)]. Eighty-three (17%) were readmitted; 296 patients (60%), were operated due to inflammatory bowel disease, 89 (18%) for cancer, 16 (3%) for diverticular disease and 95 (19%) for other diagnosis. The three most common procedures were total proctocolectomy with ileal pouch-anal anastomosis (IPAA) in 103 patients (21%), total colectomy with end ileostomy in 117 (24%) and small bowel resections (including enterocutaneous fistula takedown and J-pouch excision) in 149 (30%). The following variables were significantly more common in readmitted patients: current smoking (24% vs. 14%, p = 0.02), postoperative DVT/PE (10% vs. 4%, p = 0.04), wound infection (20% vs. 10% p = 0.01), sepsis (22% vs. 8% p < 0.001) and organ or space surgical site infection (OrgSSI) (35% vs. 5%, p < 0.001). Postoperative OrgSSI was the only independent factor associated with readmission in a multivariate analysis (p < 0.001). CONCLUSION: colorectal surgeons should be alert for OrgSSI when facing an ileostomy patient readmitted after a colorectal procedure

    Fatores de risco para prolongamento do tempo de permanĂȘncia apĂłs cirurgia colorretal

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    OBJETIVO: Os cirurgiĂ”es proctologistas muitas vezes enfrentam dificuldades para explicar aos administradores/contribuintes as razĂ”es para o prolongamento do tempo de internação hospitalar (TIH). O objetivo deste estudo foi identificar os fatores associados ao aumento do TIH apĂłs cirurgia colorretal. MÉTODO: A população do estudo incluiu pacientes que constam do banco de dados do American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) no ano de 2007 e que foram submetidos Ă  ressecção ileocĂłlica, colectomia segmentar ou ressecção anterior. A população do estudo foi dividida em normal (abaixo do percentil 75) e TIH prolongado (acima do percentil 75). A anĂĄlise multivariada foi realizada usando o TIH prolongado como variĂĄvel dependente e as variĂĄveis do ACS-NSQIP como preditivas. Um valor de p < 0,01 foi considerado significativo. RESULTADOS: No total, 12.269 pacientes com um TIH mediano de 6 dias (intervalo interquartil, 4-9) foram incluĂ­dos. Havia 2.617 pacientes (21,3%) com TIH prolongado (mediana, 15 dias; intervalo interquartil, 13-22). A idade mĂ©dia dos pacientes era de 69 anos (intervalo interquartil, 57-79) e 1.308 (50%) eram do sexo feminino. Os fatores de risco para TIH prolongado foram sexo masculino, insuficiĂȘncia cardĂ­aca congestiva, perda de peso, doença de Crohn, albumina < 3,5 g/dL e hematĂłcrito < 47% no prĂ©-operatĂłrio, sepse basal, classe ASA ≄ 3, cirurgia aberta, tempo cirĂșrgico ≄ 190 minutos, pneumonia no pĂłs-operatĂłrio, falha no desmame da ventilação mecĂąnica, trombose venosa profunda, infecção do trato urinĂĄrio, sepse sistĂȘmica, infecção do sĂ­tio cirĂșrgico e reoperação dentro de 30 dias da cirurgia primĂĄria. CONCLUSÃO: VĂĄrios fatores estĂŁo associados ao aumento do TIH apĂłs a cirurgia colorretal. Nossos resultados sĂŁo Ășteis para que os cirurgiĂ”es possam explicar os TIH prolongados aos administradores/contribuintes que sĂŁo crĂ­ticos dessa mĂ©trica.OBJECTIVE: Colorectal surgeons often struggle to explain to administrators/payers reasons for prolonged length of stay (LOS). This study aim was to identify factors associated with increased LOS after colorectal surgery. DESIGN: The study population included patients from the 2007 American-College-of-Surgeons-National-Surgical-Quality-Improvement-Program (ACS-NSQIP) database undergoing ileocolic resection, segmental colectomy, or anterior resection. The study population was divided into normal (below 75th percentile) and prolonged LOS (above the 75th percentile). A multivariate analysis was performed using prolonged LOS as dependent variable and ACS-NSQIP variables as predictive variables. P-value < 0.01 was considered significant. RESULTS: 12,269 patients with a median LOS of 6 (inter-quartile range 4-9) days were included. There were 2,617 (21.3%) patients with prolonged LOS (median 15 days, inter-quartile range 13-22). 1,308 (50%) were female, and the median age was 69 (inter-quartile range 57-79) years. Risk factors for prolonged LOS were male gender, congestive heart failure, weight loss, Crohn's disease, preoperative albumin < 3.5 g/dL and hematocrit < 47%, baseline sepsis, ASA class ≄ 3, open surgery, surgical time ≄ 190 min, postoperative pneumonia, failure to wean from mechanical ventilation, deep venous thrombosis, urinary-tract infection, systemic sepsis, surgical site infection and reoperation within 30-days from the primary surgery. CONCLUSION: Multiple factors are associated with increased LOS after colorectal surgery. Our results are useful for surgeons to explain prolonged LOS to administrators/payers who are critical of this metric

    Measurement of Neutrino-Electron Scattering Cross-Section with a CsI(Tl) Scintillating Crystal Array at the Kuo-Sheng Nuclear Power Reactor

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    The Μˉe−e−\bar{\nu}_{e}-e^{-} elastic scattering cross-section was measured with a CsI(Tl) scintillating crystal array having a total mass of 187kg. The detector was exposed to an average reactor Μˉe\bar{\nu}_{e} flux of 6.4×1012 cm−2s−1\rm{6.4\times 10^{12} ~ cm^{-2}s^{-1}} at the Kuo-Sheng Nuclear Power Station. The experimental design, conceptual merits, detector hardware, data analysis and background understanding of the experiment are presented. Using 29882/7369 kg-days of Reactor ON/OFF data, the Standard Model(SM) electroweak interaction was probed at the squared 4-momentum transfer range of Q2∌3×10−6 GeV2\rm{Q^2 \sim 3 \times 10^{-6} ~ GeV^2}. The ratio of experimental to SM cross-sections of Ο=[1.08±0.21(stat)±0.16(sys)] \xi =[ 1.08 \pm 0.21(stat)\pm 0.16(sys)] was measured. Constraints on the electroweak parameters (gV,gA)(g_V , g_A) were placed, corresponding to a weak mixing angle measurement of \s2tw = 0.251 \pm 0.031({\it stat}) \pm 0.024({\it sys}) . Destructive interference in the SM \nuebar -e process was verified. Bounds on anomalous neutrino electromagnetic properties were placed: neutrino magnetic moment at \mu_{\nuebar}< 2.2 \times 10^{-10} \mu_{\rm B} and the neutrino charge radius at -2.1 \times 10^{-32} ~{\rm cm^{2}} < \nuchrad < 3.3 \times 10^{-32} ~{\rm cm^{2}}, both at 90% confidence level.Comment: 18 Figures, 7 Tables; published version as V2 with minor revision from V

    Grassland Resistance and Resilience after Drought Depends on Management Intensity and Species Richness

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    The degree to which biodiversity may promote the stability of grasslands in the light of climatic variability, such as prolonged summer drought, has attracted considerable interest. Studies so far yielded inconsistent results and in addition, the effect of different grassland management practices on their response to drought remains an open question. We experimentally combined the manipulation of prolonged summer drought (sheltered vs. unsheltered sites), plant species loss (6 levels of 60 down to 1 species) and management intensity (4 levels varying in mowing frequency and amount of fertilizer application). Stability was measured as resistance and resilience of aboveground biomass production in grasslands against decreased summer precipitation, where resistance is the difference between drought treatments directly after drought induction and resilience is the difference between drought treatments in spring of the following year. We hypothesized that (i) management intensification amplifies biomass decrease under drought, (ii) resistance decreases with increasing species richness and with management intensification and (iii) resilience increases with increasing species richness and with management intensification

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+→Ό+ÎœW^+ \rightarrow \mu^+\nu and W−→Ό−ΜW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal
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