6,482 research outputs found
Effects of warm climatic periods on dairy cow behaviour and production in Scotland
Global warming is resulting in an overall increase in temperatures and in the frequency of extreme weather events. In dairy cattle, thresholds within the temperature-humidity index (THI) have been used to indicate points at which cattle will likely experience thermal stress (e.g., a THI threshold of 75 predicts thermal stress). However, high-yielding dairy cows that reside in temperate maritime climates may experience some degree of thermal discomfort below this threshold particularly when they are housed. Housing often results in high levels of humidity. The use of technology such as activity monitors and automated intake measures allow us to monitor responses. The aim of this study was to use technological solutions to assess behavioural changes in response to moderate increases in THI levels. Data from dairy cattle on an experimental unit were used. Data on daily lying times, lying bout frequency, step count, feed and water intake and milk yield were extracted for 8 pairs of warmer (THI<65) and 8 matching cooler (THI=43 to 60) periods. Warm and cool periods were no more than 5 weeks apart to ensure that the data from the same animals were being compared. The first three days from each period were analysed. Results showed that total daily lying time was shorter during warmer periods than cooler periods (P<0.05; means and SEMs (h): warm: 11.3±0.06h; cool: 11.8±0.06h). However, there was no effect of THI level on the no. of steps taken by cows (P>0.05 (counts) warm: 868±8 steps; cool: 878±9 steps). Water intake was higher during warm periods (P<0.05: (l) = warm: 81.2±0.7l; cool: 72.1±0.6), but there was no difference in feed intake (warm: 57.6±0.5kg; cool: 57.1±0.3kg). Milk yield was lower during warm periods than cool periods (P<0.05; (l): warm: 31.8±0.3; cool: 32.7±0.2). This suggests that behaviour and milk yield are mildly adversely affected even in conditions that are not traditionally regarded as exceeding cows’ ability to cope with thermal challenge
Effects of warm climatic periods on dairy cow behaviour and production in Scotland
Global warming is resulting in an overall increase in temperatures and in the frequency of extreme weather events. In dairy cattle, thresholds within the temperature-humidity index (THI) have been used to indicate points at which cattle will likely experience thermal stress (e.g., a THI threshold of 75 predicts thermal stress). However, high-yielding dairy cows that reside in temperate maritime climates may experience some degree of thermal discomfort below this threshold particularly when they are housed. Housing often results in high levels of humidity. The use of technology such as activity monitors and automated intake measures allow us to monitor responses. The aim of this study was to use technological solutions to assess behavioural changes in response to moderate increases in THI levels. Data from dairy cattle on an experimental unit were used. Data on daily lying times, lying bout frequency, step count, feed and water intake and milk yield were extracted for 8 pairs of warmer (THI<65) and 8 matching cooler (THI=43 to 60) periods. Warm and cool periods were no more than 5 weeks apart to ensure that the data from the same animals were being compared. The first three days from each period were analysed. Results showed that total daily lying time was shorter during warmer periods than cooler periods (P<0.05; means and SEMs (h): warm: 11.3±0.06h; cool: 11.8±0.06h). However, there was no effect of THI level on the no. of steps taken by cows (P>0.05 (counts) warm: 868±8 steps; cool: 878±9 steps). Water intake was higher during warm periods (P<0.05: (l) = warm: 81.2±0.7l; cool: 72.1±0.6), but there was no difference in feed intake (warm: 57.6±0.5kg; cool: 57.1±0.3kg). Milk yield was lower during warm periods than cool periods (P<0.05; (l): warm: 31.8±0.3; cool: 32.7±0.2). This suggests that behaviour and milk yield are mildly adversely affected even in conditions that are not traditionally regarded as exceeding cows’ ability to cope with thermal challenge
Aberrational Effects for Shadows of Black Holes
In this paper, we discuss how the shadow of a Kerr black hole depends on the
motion of the observer. In particular, we derive an analytical formula for the
boundary curve of the shadow for an observer moving with given four-velocity at
given Boyer--Lindquist coordinates. We visualize the shadow for various values
of parameters.Comment: 12 pages, 3 figures; Proceedings of the 524. WE-Heraeus-Seminar held
at the Physikzentrum, Bad Honnef, Germany, 17.--23.2.201
The Effect of Synthesis Parameters on the Catalytic Synthesis of Multiwalled Carbon Nanotubes using Fe-Co/CaCO3 Catalysts
Fe-Co bimetallic catalysts supported on CaCO3 were prepared by a wet impregnation, a deposition-precipitation and a reverse micelle method. The sizes of the Fe and Co particles were not affected by the Fe and Co sources (nitrate, acetate) when the wet impregnation and deposition-precipitation methods were used. ‘Clean’ multi-walled carbon nanotubes (MWCNTs) were obtained from all three Fe-Co synthesis procedures under optimal reaction conditions. The CNTs produced gave yields ranging from 623 % to 1215 % in 1 h under the optimal conditions, with similar outer diameters (o.d.) of 20–30 nm and inner diameters (i.d.) ~10 nm. The Fe/Co catalyst formedin the wet impregnation method revealed that the yield, diameter and purity of the CNTs were influenced by the C2H2/N2 ratio, time and temperature. All the methods gave high-quality CNTs after short reaction times but the quality deteriorated as the synthesis time was increased from 5 to 360 min. Indeed, the most influential parameter in controlling CNT purity, length and o.d. was found to be the synthesis time. The as-synthesized CNTs were purified using a single-step mild acid treatment process (30 % HNO3), which readily removed the support and metal particles.Keywords: Carbon nanotubes, synthesis, bimetallic catalyst, iron, cobaltPDF and Supplementry file attache
Mobility, functionality and functional mobility: A review and application for canine veterinary patients
Mobility is an essential aspect of a dog’s daily life. It is defined as the ability to move freely and easily and deviations from an animals’ normal mobility capabilities are often an indicator of disease, injury or pain. When a dog’s mobility is compromised, often functionality (ability to perform activities of daily living; ADL), is also impeded, which can diminish an animal’s quality of life. Given this, it is necessary to understand the extent to which conditions impact a dog’s physiological ability to freely move around their environment to carry out ADL, a concept termed functional mobility. In contrast to human medicine, validated measures of canine functional mobility are currently limited. The aim of this review is to summarise the extent to which canine mobility and functionality are associated with various diseases and how mobility and functional mobility are currently assessed within veterinary medicine. Future work should focus on developing a standardised method of assessing functional mobility in dogs, which can contextualise how a wide range of conditions impact a dog’s daily life. However, for a true functional mobility assessment to be developed, a greater understanding of what activities dogs do on a daily basis and movements underpinning these activities must first be established
Computational Analysis of Flight Deck Structural Behaviour under Variable Loadings
The flight deck of an aircraft carrier is subjected to various loads. In addition, the operation of fixed-wing aircraft presents unique structural requirements for the deck. This paper, therefore, compares the structural behaviour of a flight deck which was designed following the guidelines of three classification societies: Lloyd’s Register (LR), Det Norske Veritas Germanischer Lloyd (DNV), and Registro Italiano Navale (RINA). The loading scenarios considered in this work represent the operation of an F-35B Lightning jet from a Queen Elizabeth-class (QEC) aircraft carrier. A commercial finite element analysis (FEA) software ANSYS was also used to investigate the deflection, stress and strain on the deck plates. The analysis identified that only the calculated deck thickness values based on the LR regulations would meet the requirement for the class. This finding was further supported by the FEA.</jats:p
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Calorimetric observation of single He2* excimers in a 100 mK He bath
We report the first calorimetric detection of individual He2* excimers within a bath of superfluid 4He. The detector used in this work is a single superconducting titanium transition edge sensor (TES) with an energy resolution of 1 eV, immersed directly in the helium bath. He2* excimers are produced in the surrounding bath using an external gamma-ray source. These excimers exist either as short-lived singlet or long-lived triplet states. We demonstrate detection (and discrimination) of both states: in the singlet case the calorimeter records the absorption of a prompt 15 eV photon, and in the triplet case the calorimeter records a direct interaction of the molecule with the TES surface, which deposits a distinct fraction of the 15 eV, released upon decay, into the surface. We also briefly discuss the detector fabrication and characterization
A mechanistic modelling approach for the determination of the mechanisms of inhibition by cyclosporine on the uptake and metabolism of atorvastatin in rat hepatocytes using a high throughput uptake method
(1) Determine the inhibition mechanism through which cyclosporine inhibits the uptake and metabolism of atorvastatin in fresh rat hepatocytes using mechanistic models applied to data generated using a high throughput oil spin method.
(2) Atorvastatin was incubated in fresh rat hepatocytes (0.05–150 nmol/ml) with or without 20 min pre-incubation with 10 nmol/ml cyclosporine and sampled over 0.25–60 min using a high throughput oil spin method. Micro-rate constant and macro-rate constant mechanistic models were ranked based on goodness of fit values.
(3) The best fitting model to the data was a micro-rate constant mechanistic model including non-competitive inhibition of uptake and competitive inhibition of metabolism by cyclosporine (Model 2). The association rate constant for atorvastatin was 150-fold greater than the dissociation rate constant and 10-fold greater than the translocation into the cell. The association and dissociation rate constants for cyclosporine were 7-fold smaller and 10-fold greater, respectively, than atorvastatin. The simulated atorvastatin-transporter-cyclosporine complex derived using the micro-rate constant parameter estimates increased in line with the incubation concentration of atorvastatin.
(4) The increased amount of data generated with the high throughput oil spin method, combined with a micro-rate constant mechanistic model helps to explain the inhibition of uptake by cyclosporine following pre-incubation
Selection on an antagonistic behavioral trait can drive rapid genital coevolution in the burying beetle, Nicrophorus vespilloides
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Male and female genital morphology varies widely across many taxa, and even among populations. Disentangling potential sources of selection on genital morphology is problematic because each sex is predicted to respond to adaptations in the other due to reproductive conflicts of interest. To test how variation in this sexual conflict trait relates to variation in genital morphology we used our previously developed artificial selection lines for high and low repeated mating rates. We selected for high and low repeated mating rates using monogamous pairings to eliminate contemporaneous female choice and male-male competition. Male and female genital shape responded rapidly to selection on repeated mating rate. High and low mating rate lines diverged from control lines after only 10 generations of selection. We also detected significant patterns of male and female genital shape coevolution among selection regimes. We argue that because our selection lines differ in sexual conflict, these results support the hypothesis that sexually antagonistic coevolution can drive the rapid divergence of genital morphology. The greatest divergence in morphology corresponded with lines in which the resolution of intrasexual conflict over mating rate was biased in favor of male interests.Funding was provided by Natural Environment Research Council grants NE/I025468/1 to N.J.R. and A.J.M., and NE/H003738/1 to A.J.M
The efficacy of a lateral wedge insole for painful medial knee osteoarthritis after prescreening : a randomized clinical trial
OBJECTIVE:
Lateral wedge shoe insoles decrease medial knee loading, but trials have shown no effect on pain in medial knee osteoarthritis (OA). However, insoles' loading effects are inconsistent, and they can increase patellofemoral loading. We hypothesized that insoles would reduce pain in preselected patients.
METHODS:
In persons with painful medial knee OA, we excluded those with patellofemoral OA and those with pain <4/10. We further excluded participants who, in a gait laboratory using lateral wedges, did not show at least a 2% reduction in knee adduction moment (KAM) compared with their shoes and a neutral insole. We then randomized subjects to lateral wedge vs. neutral insole for 8 week periods separated by an 8 week washout. Primary outcome was knee pain over the past week (0-10) and secondary outcomes nominated activity pain and KOOS pain. We carried out mixed model analyses adjusted for baseline pain.
RESULTS:
Of 83 participants, 21 (25%) were excluded because of insufficient reduction in KAM. Of 62 included, mean age was 64.2 years (SD 9.1); 37.1% were women. Lateral wedge insoles produced a greater reduction in knee pain than neutral insoles (difference 0.7 on 0-10 scale; 95%CI 0.1, 1.2; p = 0.02). Secondary outcomes showed mixed findings.
CONCLUSIONS:
In persons prescreened to eliminate those with patellofemoral OA and biomechanical non-responders, lateral wedge insoles reduced knee pain, but the effect of treatment was small and is likely of clinical significance in only a minority of patients. Targeting patients may identify those who respond to this treatment
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