99 research outputs found

    Development of a variable stocking rate allocation model (VSRAM) in southern Patagonia

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    El ajuste de la carga animal es un aspecto clave en el manejo del pastoreo extensivo y en Santa Cruz, Argentina se realiza tradicionalmente utilizando una asignación fija de forraje (AFF) por animal, indistintamente si un potrero se utiliza continuamente durante el año o se usa estacionalmente durante el invierno. En este trabajo se generó un modelo para asignación variable de carga (MAVC) que contempla aspectos biológicos de balance de biomasa y calidad del pastizal relacionado con distintas variables del animal. El modelo se generó para 6 áreas ecológicas de Patagonia Sur: Pastizal Subandino, Matorral de Mata Negra, Estepa Magallánica Seca, Estepa Magallánica Húmeda, Complejo Andino y Ecotono Fueguino y puede ser utilizado en campos con uso continuo o estacional.El análisis de sensibilidad mostró que la variable porcentaje en dieta de forraje (variable que estima el consumo del animal) fue la más influyente en la respuesta del modelo. La variable de respuesta Residuo Forrajero Estimado por el modelo fue explicada satisfactoriamente por sus variables predictoras (Carga Animal Previa, Carga Animal Propuesta y Disponibilidad Forrajera) y resultó acorde con los datos de residuos forrajeros obtenidos durante los chequeos a campo (R2==0.91; p<0.01). Los resultados indican que el MAVC arroja valores similares a los cálculos realizados mediante AFF cuando los campos son utilizados anualmente. Por el contrario, cuando se evalúa el uso invernal, el modelo propone menores valores de carga animal que el método tradicional. El modelo MACV desarrollado en el presente trabajo ha logrado un balance entre complejidad y practicidad en la estimación de la capacidad de carga animal, lo cual sugiere que es una herramienta importante que puede ser utilizada en el manejo de los sistemas ganaderos en los pastizales de Patagonia Sur.Stocking rate adjustment is a key aspect in extensive grazing management. In Santa Cruz, Argentina, sheep carrying capacity is estimated through a fixed forage allowance (FFA) regardless of paddock use. In this work, we developed a variable stocking rate allocation model (VSRAM) based on the simulation of forage biomass and quality dynamics and the setting of critical residue targets at the end of the grazing period. The model was generated for 6 ecological areas of southern Patagonia and it can be used in paddocks with continuous or seasonal use. Model sensitivity analysis showed that the diet was the most sensitive variable for stocking rate estimations. We found a significant lineal correlation between values estimated by VSRAM and data observed in the field (R2=0.91; p<0.01). The results indicated that stocking rate estimation from the model and FFA had similar values when paddocks were used on an annual basis. However, when paddocks are used for short periods in winter, the model predicted lower stocking rate values than the traditional method. The VSRAM model achieved a balance between complexity and practicability for sheep carrying capacity determination. Our results suggest that this model is an important tool that can be used in the management of livestock systems in grasslands of South Patagonia.Fil: Andrade, Miguel Alberto. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz.; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; ArgentinaFil: Suarez, Diego D.. No especifíca;Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz.; ArgentinaFil: Borrelli, Nicolas Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. OVIS 21; ArgentinaFil: Ormaechea, Sebastián Gabriel. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz.; ArgentinaFil: Ferrante, Daniela. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz.; Argentina. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; ArgentinaFil: Rivera, Emilio H.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz.; ArgentinaFil: Sturzenbaum, María Virginia. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional.patagonia Sur. Estacion Experimental Agropecuaria Santa Cruz.; Argentin

    First radial velocity results from the MINiature Exoplanet Radial Velocity Array (MINERVA)

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    The MINiature Exoplanet Radial Velocity Array (MINERVA) is a dedicated observatory of four 0.7m robotic telescopes fiber-fed to a KiwiSpec spectrograph. The MINERVA mission is to discover super-Earths in the habitable zones of nearby stars. This can be accomplished with MINERVA's unique combination of high precision and high cadence over long time periods. In this work, we detail changes to the MINERVA facility that have occurred since our previous paper. We then describe MINERVA's robotic control software, the process by which we perform 1D spectral extraction, and our forward modeling Doppler pipeline. In the process of improving our forward modeling procedure, we found that our spectrograph's intrinsic instrumental profile is stable for at least nine months. Because of that, we characterized our instrumental profile with a time-independent, cubic spline function based on the profile in the cross dispersion direction, with which we achieved a radial velocity precision similar to using a conventional "sum-of-Gaussians" instrumental profile: 1.8 m s1^{-1} over 1.5 months on the RV standard star HD 122064. Therefore, we conclude that the instrumental profile need not be perfectly accurate as long as it is stable. In addition, we observed 51 Peg and our results are consistent with the literature, confirming our spectrograph and Doppler pipeline are producing accurate and precise radial velocities.Comment: 22 pages, 9 figures, submitted to PASP, Peer-Reviewed and Accepte

    Perivascular spaces are associated with tau pathophysiology and synaptic dysfunction in early Alzheimer’s continuum

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    Background: Perivascular spaces (PVS) have an important role in the elimination of metabolic waste from the brain. It has been hypothesized that the enlargement of PVS (ePVS) could be affected by pathophysiological mechanisms involved in Alzheimer’s disease (AD), such as abnormal levels of CSF biomarkers. However, the relationship between ePVS and these pathophysiological mechanisms remains unknown. Objective: We aimed to investigate the association between ePVS and CSF biomarkers of several pathophysiological mechanisms for AD. We hypothesized that ePVS will be associated to CSF biomarkers early in the AD continuum (i.e., amyloid positive cognitively unimpaired individuals). Besides, we explored associations between ePVS and demographic and cardiovascular risk factors. Methods: The study included 322 middle-aged cognitively unimpaired participants from the ALFA + study, many within the Alzheimer’s continuum. NeuroToolKit and Elecsys® immunoassays were used to measure CSF Aβ42, Aβ40, p-tau and t-tau, NfL, neurogranin, TREM2, YKL40, GFAP, IL6, S100, and α-synuclein. PVS in the basal ganglia (BG) and centrum semiovale (CS) were assessed based on a validated 4-point visual rating scale. Odds ratios were calculated for associations of cardiovascular and AD risk factors with ePVS using logistic and multinomial models adjusted for relevant confounders. Models were stratified by Aβ status (positivity defined as Aβ42/40 < 0.071). Results: The degree of PVS significantly increased with age in both, BG and CS regions independently of cardiovascular risk factors. Higher levels of p-tau, t-tau, and neurogranin were significantly associated with ePVS in the CS of Aβ positive individuals, after accounting for relevant confounders. No associations were detected in the BG neither in Aβ negative participants. Conclusions: Our results support that ePVS in the CS are specifically associated with tau pathophysiology, neurodegeneration, and synaptic dysfunction in asymptomatic stages of the Alzheimer’s continuum

    Efficacy of rifabutin-based triple therapy as second-line treatment to eradicate helicobacter pylori infection

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    <p>Abstract</p> <p>Background</p> <p>Rifabutin has been found to be effective in multi-resistant patients after various treatment cycles for Helicobacter pylori (HP) infection, but it has not been analysed as a second-line treatment. Therefore, we seek to compare the effectiveness of a treatment regimen including rifabutin versus conventional quadruple therapy (QT).</p> <p>Methods</p> <p>Open clinical trial, randomised and multi-centre, of two treatment protocols: A) Conventional regime -QT- (omeprazole 20 mg bid, bismuth citrate 120 mg qid, tetracycline 500 mg qid and metronidazole 500 mg tid); B) Experimental one -OAR- (omeprazole 20 mg bid, amoxicillin 1 gr bid, and rifabutin 150 mg bid), both taken orally for 7 days, in patients with HP infection for whom first-line treatment had failed. Eradication was determined by Urea Breath Test (UBT). Safety was determined by the adverse events.</p> <p>Results</p> <p>99 patients were randomised, QT, n = 54; OAR, n = 45. The two groups were homogeneous. In 8 cases, treatment was suspended (6 in QT and 2 in OAR). The eradication achieved, analysed by ITT, was for QT, 38 cases (70.4%), and for OAR, 20 cases (44.4%); p = 0.009, OR = 1.58. Of the cases analysed PP, QT were 77.1%; OAR, 46.5%; p = 0.002. Adverse effects were described in 64% of the QT patients and in 44% of the OAR patients (p = 0.04).</p> <p>Conclusion</p> <p>A 7-day rifabutin-based triple therapy associated to amoxicillin and omeprazole at standard dose was not found to be effective as a second-line rescue therapy. The problem with quadruple therapy lies in the adverse side effects it provokes. We believe the search should continue for alternatives that are more comfortably administered and that are at least as effective, but with fewer adverse side effects.</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN81058036</p

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Genetic Drivers of Kidney Defects in the DiGeorge Syndrome

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    Background The DiGeorge syndrome, the most common of the microdeletion syndromes, affects multiple organs, including the heart, the nervous system, and the kidney. It is caused by deletions on chromosome 22q11.2; the genetic driver of the kidney defects is unknown. Methods We conducted a genomewide search for structural variants in two cohorts: 2080 patients with congenital kidney and urinary tract anomalies and 22,094 controls. We performed exome and targeted resequencing in samples obtained from 586 additional patients with congenital kidney anomalies. We also carried out functional studies using zebrafish and mice. Results We identified heterozygous deletions of 22q11.2 in 1.1% of the patients with congenital kidney anomalies and in 0.01% of population controls (odds ratio, 81.5; P=4.5×10(-14)). We localized the main drivers of renal disease in the DiGeorge syndrome to a 370-kb region containing nine genes. In zebrafish embryos, an induced loss of function in snap29, aifm3, and crkl resulted in renal defects; the loss of crkl alone was sufficient to induce defects. Five of 586 patients with congenital urinary anomalies had newly identified, heterozygous protein-altering variants, including a premature termination codon, in CRKL. The inactivation of Crkl in the mouse model induced developmental defects similar to those observed in patients with congenital urinary anomalies. Conclusions We identified a recurrent 370-kb deletion at the 22q11.2 locus as a driver of kidney defects in the DiGeorge syndrome and in sporadic congenital kidney and urinary tract anomalies. Of the nine genes at this locus, SNAP29, AIFM3, and CRKL appear to be critical to the phenotype, with haploinsufficiency of CRKL emerging as the main genetic driver. (Funded by the National Institutes of Health and others.)

    Consistent improvement with eculizumab across muscle groups in myasthenia gravis

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    The present gravitational wave detection effort

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    Gravitational radiation offers a new non-electromagnetic window through which to observe the universe. The LIGO and Virgo Collaborations have completed a first joint data run with unprecedented sensitivities to gravitational waves. Results from searches in the data for a variety of astrophysical sources are presented. A second joint data run with improved detector sensitivities is underway, and soon major upgrades will be carried out to build Advanced LIGO and Advanced Virgo with expected improvements in event rates of more than 1000. In parallel there is a vigorous effort in the radio pulsar community to detect nHz gravitational waves via the timing residuals in an array of pulsars at different locations in the sky.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85430/1/jpconf10_203_012002.pd

    Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

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    Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

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