560 research outputs found

    Feeding Concentrate Formulated With Native Irish Feed Ingredients and a Low Crude Protein Content to Grazing Dairy Cows Has No Effect on Milk Production or Milk Composition

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    Improving nitrogen use efficiency (NUE) and feeding native feed ingredients offers potential to improve the environmental sustainability of dairy production. However, improving NUE is a key challenge in grass-based systems due to high crude protein (CP) levels in grass and low nitrogen retention by dairy cows. In addition, concentrate feed typically contains imported feed ingredients which contribute to increased carbon footprint. Therefore, the objective of this study was to investigate the effect of concentrate CP level and ingredient source on milk production and composition. Forty-two mixed-parity Holstein-Friesian cows were blocked on parity and balanced on days in milk (DIM), milk production, BCS and Economic Breeding Index (EBI; n=14). Cows grazed full time and were offered a basal diet of perennial ryegrass pasture (average 17 kg DM/cow/day) and fed one of three concentrate supplements at varying levels according to DIM during the main grazing season (153 days). The concentrate treatments (T) were: T1) 14% CP concentrate formulated with non-native ingredients, T2) 12% CP concentrate formulated with non-native ingredients or T3) 12% CP concentrate formulated with native ingredients. Reducing the CP level or formulating with native feed ingredients did not alter milk or milk solids yield (T1: 25.7 kg/day, 2.11 kg/day; T2: 25.3 kg/day, 2.06 kg/day; T3: 24.9 kg/day, 2.01 kg/day respectively). Similarly, no effect of treatment was observed for milk fat or protein percentage (T1: 4.40 %, 3.66 %; T2: 4.44 %, 3.64 %; T3: 4.37 %, 3.66 %, respectively). The results of this study highlight that the sustainability of grass-based dairy may be improved by using a low concentrate CP content (12%) in addition to offering concentrate feed based on native feed ingredients which can result in similar performance to that of dairy cows offered a 14% CP concentrate or a concentrate based on imported ingredients respectively

    The mineral diversity of Jezero crater: Evidence for possible lacustrine carbonates on Mars

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    Noachian-aged Jezero crater is the only known location on Mars where clear orbital detections of carbonates are found in close proximity to clear fluvio-lacustrine features indicating the past presence of a paleolake; however, it is unclear whether or not the carbonates in Jezero are related to the lacustrine activity. This distinction is critical for evaluating the astrobiological potential of the site, as lacustrine carbonates on Earth are capable of preserving biosignatures at scales that may be detectable by a landed mission like the Mars 2020 rover, which is planned to land in Jezero in February 2021. In this study, we conduct a detailed investigation of the mineralogical and morphological properties of geological units within Jezero crater in order to better constrain the origin of carbonates in the basin and their timing relative to fluvio-lacustrine activity. Using orbital visible/near-infrared hyperspectral images from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) along with high resolution imagery and digital elevation models, we identify a distinct carbonate-bearing unit, the “Marginal Carbonates,” located along the inner margin of the crater, near the largest inlet valley and the western delta. Based on their strong carbonate signatures, topographic properties, and location in the crater, we propose that this unit may preserve authigenic lacustrine carbonates, precipitated in the near-shore environment of the Jezero paleolake. Comparison to carbonate deposits from terrestrial closed basin lakes suggests that if the Marginal Carbonates are lacustrine in origin, they could preserve macro- and microscopic biosignatures in microbialite rocks like stromatolites, some of which would likely be detectable by Mars 2020. The Marginal Carbonates may represent just one phase of a complex fluvio-lacustrine history in Jezero crater, as we find that the spectral diversity of the fluvio-lacustrine deposits in the crater is consistent with a long-lived lake system cataloging the deposition and erosion of regional geologic units. Thus, Jezero crater may contain a unique record of the evolution of surface environments, climates, and habitability on early Mars

    Plasma amyloid-β ratios in autosomal dominant Alzheimer's disease: the influence of genotype.

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    In-vitro studies of autosomal dominant Alzheimer's disease implicate longer amyloid-beta peptides in disease pathogenesis, however less is known about the behaviour of these mutations in-vivo. In this cross-sectional cohort study, we used liquid chromatography-tandem mass spectrometry to analyse 66 plasma samples from individuals who were at-risk of inheriting a mutation or were symptomatic. We tested for differences in amyloid-beta42:38, 42:40 and 38:40 ratios between presenilin1 and amyloid precursor protein carriers. We examined the relationship between plasma and in-vitro models of amyloid-beta processing and tested for associations with parental age at onset. 39 participants were mutation carriers (28 presenilin1 and 11 amyloid precursor protein). Age- and sex-adjusted models showed marked differences in plasma amyloid-beta between genotypes: higher amyloid-beta42:38 in presenilin1 versus amyloid precursor protein (p < 0.001) and non-carriers (p < 0.001); higher amyloid-beta38:40 in amyloid precursor protein versus presenilin1 (p < 0.001) and non-carriers (p < 0.001); while amyloid-beta42:40 was higher in both mutation groups compared to non-carriers (both p < 0.001). Amyloid-beta profiles were reasonably consistent in plasma and cell lines. Within presenilin1, models demonstrated associations between amyloid-beta42:38, 42:40 and 38:40 ratios and parental age at onset. In-vivo differences in amyloid-beta processing between presenilin1 and amyloid precursor protein carriers provide insights into disease pathophysiology, which can inform therapy development

    The frequency of giant planets around metal-poor stars

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    Context. The discovery of about 700 extrasolar planets, so far, has lead to the first statistics concerning extrasolar planets. The presence of giant planets seems to depend on stellar metallicity and mass. For example, they are more frequent around metal-rich stars,with an exponential increase in planet occurrence rates with metallicity. Aims. We analyzed two samples of metal-poor stars (-2.0 \leq [Fe/H] \leq 0.0) to see if giant planets are indeed rare around these objects. Radial velocity datasets were obtained with two different spectrographs (HARPS and HIRES). Detection limits for these data,expressed in minimum planetary mass and period, are calculated. These produce trustworthy numbers for the planet frequency. Methods. A general Lomb Scargle (GLS) periodogram analysis was used together with a bootstrapping method to produce the detection limits. Planet frequencies were calculated based on a binomial distribution function within metallicity bins. Results. Almost all hot Jupiters and most giant planets should have been found in these data. Hot Jupiters around metal-poor stars have a frequency lower than 1.0% at one sigma. Giant planets with periods up to 1800 days, however, have a higher frequency of fp=2.630.8+2.5f_p = 2.63^{+2.5}_{-0.8}%. Taking into account the different metallicities of the stars, we show that giant planets appear to be very frequent (fp=4.481.38+4.04(f_p = 4.48^{+4.04}_{-1.38}%) around stars with [Fe/H] > -0.7, while they are rare around stars with [Fe/H] \leq -0.7 (\leq 2.36% at one sigma). Conclusions. Giant planet frequency is indeed a strong function of metallicity, even in the low-metallicity tail. However, the frequencies are most likely higher than previously thought.Comment: Accepted to A&A, 8 pages, 6 figures, 2 table

    The osteoarthritis prevention study (TOPS) - A randomized controlled trial of diet and exercise to prevent Knee Osteoarthritis:Design and rationale

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    Background: Osteoarthritis (OA), the leading cause of disability among adults, has no cure and is associated with significant comorbidities. The premise of this randomized clinical trial is that, in a population at risk, a 48-month program of dietary weight loss and exercise will result in less incident structural knee OA compared to control. Methods/design: The Osteoarthritis Prevention Study (TOPS) is a Phase III, assessor-blinded, 48-month, parallel 2 arm, multicenter randomized clinical trial designed to reduce the incidence of structural knee OA. The study objective is to assess the effects of a dietary weight loss, exercise, and weight-loss maintenance program in preventing the development of structural knee OA in females at risk for the disease. TOPS will recruit 1230 ambulatory, community dwelling females with obesity (Body Mass Index (BMI) ​≥ ​30 ​kg/m2) and aged ≥50 years with no radiographic (Kellgren-Lawrence grade ≤1) and no magnetic resonance imaging (MRI) evidence of OA in the eligible knee, with no or infrequent knee pain. Incident structural knee OA (defined as tibiofemoral and/or patellofemoral OA on MRI) assessed at 48-months from intervention initiation using the MRI Osteoarthritis Knee Score (MOAKS) is the primary outcome. Secondary outcomes include knee pain, 6-min walk distance, health-related quality of life, knee joint loading during gait, inflammatory biomarkers, and self-efficacy. Cost effectiveness and budgetary impact analyses will determine the value and affordability of this intervention. Discussion: This study will assess the efficacy and cost effectiveness of a dietary weight loss, exercise, and weight-loss maintenance program designed to reduce incident knee OA.Trial registration: ClinicalTrials.gov Identifier: NCT05946044.</p

    A Requirement of TolC and MDR Efflux Pumps for Acid Adaptation and GadAB Induction in Escherichia coli

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    BACKGROUND: The TolC outer membrane channel is a key component of several multidrug resistance (MDR) efflux pumps driven by H(+) transport in Escherichia coli. While tolC expression is under the regulation of the EvgA-Gad acid resistance regulon, the role of TolC in growth at low pH and extreme-acid survival is unknown. METHODS AND PRINCIPAL FINDINGS: TolC was required for extreme-acid survival (pH 2) of strain W3110 grown aerobically to stationary phase. A tolC deletion decreased extreme-acid survival (acid resistance) of aerated pH 7.0-grown cells by 10(5)-fold and of pH 5.5-grown cells by 10-fold. The requirement was specific for acid resistance since a tolC defect had no effect on aerobic survival in extreme base (pH 10). TolC was required for expression of glutamate decarboxylase (GadA, GadB), a key component of glutamate-dependent acid resistance (Gad). TolC was also required for maximal exponential growth of E. coli K-12 W3110, in LBK medium buffered at pH 4.5-6.0, but not at pH 6.5-8.5. The TolC growth requirement in moderate acid was independent of Gad. TolC-associated pump components EmrB and MdtB contributed to survival in extreme acid (pH 2), but were not required for growth at pH 5. A mutant lacking the known TolC-associated efflux pumps (acrB, acrD, emrB, emrY, macB, mdtC, mdtF, acrEF) showed no growth defect at acidic pH and a relatively small decrease in extreme-acid survival when pre-grown at pH 5.5. CONCLUSIONS: TolC and proton-driven MDR efflux pump components EmrB and MdtB contribute to E. coli survival in extreme acid and TolC is required for maximal growth rates below pH 6.5. The TolC enhancement of extreme-acid survival includes Gad induction, but TolC-dependent growth rates below pH 6.5 do not involve Gad. That MDR resistance can enhance growth and survival in acid is an important consideration for enteric organisms passing through the acidic stomach

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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