17,414 research outputs found
Weaning lambs under pastoral conditions
IN the summer rainfall region of the pastoral areas lambs are too often born too late to ensure their survival.
In good seasons with a fair measure of winter rain more late lambs will survive, but losses are still serious. The only solution to this problem is to make sure lambs drop in May-June.
But the presence of late and often unmarked lambs at mating time is a disturbing influence, which makes it hard to advance the established mating pattern
Relaxation of strained silicon on Si0.5Ge0.5 virtual substrates
Strain relaxation has been studied in tensile strained silicon layers grown on Si0.5Ge0.5 virtual substrates, for layers many times the critical thickness, using high resolution x-ray diffraction. Layers up to 30 nm thick were found to relax less than 2% by the glide of preexisting 60° dislocations. Relaxation is limited because many of these dislocations dissociate into extended stacking faults that impede the dislocation glide. For thicker layers, nucleated microtwins were observed, which significantly increased relaxation to 14%. All these tensile strained layers are found to be much more stable than layers with comparable compressive strain
Three-dimensional flow structure and bed morphology in large elongate meander loops with different outer bank roughness characteristics
© 2016. American Geophysical Union. All Rights Reserved. Few studies have examined the three-dimensional flow structure and bed morphology within elongate loops of large meandering channels. The present study focuses on the spatial patterns of three-dimensional flow structure and bed morphology within two elongate meander loops and examines how differences in outer bank roughness influence near-bank flow characteristics. Three-dimensional velocities were measured during two different eventsâa near-bankfull flow and an overbank event. Detailed data on channel bathymetry and bed form geometry were obtained during a near-bankfull event. Flow structure within the loops is characterized by strong topographic steering by the point bar, by the development of helical motion associated with flow curvature, and by acceleration of flow where bedrock is exposed along the outer bank. Near-bank velocities during the overbank event are less than those for the near-bankfull flow, highlighting the strong influence of the point bar on redistribution of mass and momentum of the flow at subbankfull stages. Multiple outer bank pools are evident within the elongate meander loop with low outer bank roughness, but are not present in the loop with high outer bank roughness, which may reflect the influence of abundant large woody debris on near-bank velocity characteristics. The positions of pools within both loops can be linked to spatial variations in planform curvature. The findings indicate that flow structure and bed morphology in these large elongate loops is similar to that in small elongate loops, but differs somewhat from flow structure and bed morphology reported for experimental elongate loops
Detection of lithium in nearby young late-M dwarfs
Late M-type dwarfs in the solar neighborhood include a mixture of very
low-mass stars and brown dwarfs which is difficult to disentangle due to the
lack of constraints on their age such as trigonometric parallax, lithium
detection and space velocity.
We search for young brown dwarf candidates among a sample of 28 nearby late-M
dwarfs with spectral types between M5.0 and M9.0, and we also search for debris
disks around three of them.
Based on theoretical models, we used the color , the -band absolute
magnitude and the detection of the Li I 6708 doublet line as a strong
constraint to estimate masses and ages of our targets. For the search of debris
disks, we observed three targets at submillimeter wavelength of 850 m.
We report here the first clear detections of lithium absorption in four
targets and a marginal detection in one target. Our mass estimates indicate
that two of them are young brown dwarfs, two are young brown dwarf candidates
and one is a young very low-mass star. The closest young field brown dwarf in
our sample at only 15 pc is an excellent benchmark for further studying
physical properties of brown dwarfs in the range 100150 Myr. We did not
detect any debris disks around three late-M dwarfs, and we estimated upper
limits to the dust mass of debris disks around them.Comment: 10 pages, 5 figures, accepted for publication in Astronomy and
Astrophysic
Protocol for a single-centre randomised controlled trial of multimodal periarticular anaesthetic infiltration versus single-agent femoral nerve blockade as analgesia for total knee arthroplasty: Perioperative Analgesia for Knee Arthroplasty (PAKA)
Introduction: Total knee arthroplasty (TKA) surgery causes postoperative pain. The use of perioperative injections around the knee containing local anaesthetic, opiates and non-steroidal anti-inflammatory drugs has increased in popularity to manage pain. Theoretical advantages include reduced requirements for analgesia and earlier mobilisation. We propose a single-centre randomised controlled trial of multimodal periarticular anaesthetic infiltration versus femoral nerve anaesthetic blockade as analgesia for TKA. The aim is to determine, in patients undergoing TKA, if there is a difference in patient-reported pain scores on the visual analogue scale (VAS) prior to physiotherapy on day 1 postoperatively between treatment groups.
Methods and analysis: Patients undergoing a primary unilateral TKA at University Hospitals Coventry and Warwickshire Hospitals will be assessed for eligibility. A total of 264 patients will provide 90% power to detect a difference of 12â
mm on the VAS on day 1 postoperatively at the 5% level. The trial will use 1:1 randomisation, stratified by mode of anaesthetic. Primary outcome measure will be the VAS for pain prior to physiotherapy on day 1. Secondary outcome measures include VAS on day 2, total use of opiate analgesia up to 48â
h, ordinal pain scores up to 40â
min after surgery, independent functional knee physiotherapist assessment on days 1 and 2. Oxford knee Scores (OKS), EuroQol (EQ-5D) and Douleur Neuropathic Pain Scores (DN2) will be recorded at baseline, 6â
weeks and 12â
months. Adverse events will be recorded up to 12â
months. Analysis will investigate differences in VAS on day 1 between the two treatment groups on an intention-to-treat basis. Tests will be two-sided and considered to provide evidence for a significant difference if p values are less than 0.05.
Ethics and dissemination: NRES Committee West Midlands, 23 September 2013 (ref: 13/WM/0316). The results will be disseminated via peer-reviewed publications and conference presentations.
Trial registration numbers: ISRCTN 60611146 and EUDRACT Number 2013-002439-10 (protocol code number PAKA-33601-AS117013); Pre-results
A systematic review of patient reported outcome measures (PROMs) and quality of life reporting in patients undergoing laparoscopic cholecystectomy
Background Patient Reported Outcome Measures (PROMs) provide a valuable means of measuring outcomes subjectively from a patient's perspective, facilitating the assessment of service quality across healthcare providers, and assisting patients and clinicians in shared decision making. The primary aim of this systematic review was to critically appraise all historic studies evaluating patient reported quality of life, in adult patients undergoing laparoscopic cholecystectomy for symptomatic gallstones. The secondary aim was to perform a quality assessment of cholecystectomy-specific PROM-validation studies. Methods A literature review was performed in PubMed, Google ScholarTM, the Cochrane Library, Medline, CINAHL, EMBASE and PsychINFO databases up to September 2017. Study characteristics, PROM-specific details and a bias assessment were summarised for non-validation studies. A COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) analysis was performed to assess the methodological quality of identified PROM-validation studies. Results Fifty one studies were found to evaluate Health-Related Quality of Life (HRQoL) after laparoscopic cholecystectomy. Although 94.1% of these studies included PROMs as a primary outcome measure
Evidence of Low-Temperature Superparamagnetism in Mn_{4}$ Nanoparticle Ensembles
Please refer to the abstract within the main body of the paper
Extremes in dune preservation: controls on the completeness of fluvial deposits
Understanding sedimentary preservation underpins our ability to interpret the ancient sedimentary record and reconstruct palaeoenvironments and palaeoclimates. Dune sets are ubiquitous in preserved river deposits and are typically interpreted based on a model that that describes the recurrence of erosion in a vertical sequence, but without consideringspatial variability. However, spatial variability in flow and sediment transport will change the recurrence of erosion, and therefore dune preservation. In order to better understand the limits of these Interpretations and outline the causes of potential variability in preservation potential, this paper reviews existing work and presents new observations of an extreme end-member of dune preservation: ?form-sets?, formed by dunes in which both stoss- and lee- slopes are preserved Intact. These form-sets do not conform to models that are based on the recurrence of erosion, since erosion does not recur in their case, and can therefore be used to evaluate the assumptions that underpin sedimentary preservation. New Ground Penetrating Radar data from the RĂo ParanĂĄ, Argentina, show dune fields that are buried intact within larger scale barforms. These trains of form-sets are up to 300 m in length, are restricted to unit-bar troughs in the upper 5 m of the channel deposits, occur in >5% of the mid-channel bar deposits, show reactivation surfaces, occur in multiple levels, and match the size of average-flow dunes. A review of published accounts of form-sets highlights a diversity of processes that can be envisaged for their formation: i) abandonment after extreme floods, ii) slow burial of abandoned dune forms by cohesive clay in sheltered bar troughs and meander-neck cut-offs, iii) fast burial by mass-movement processes, and iv)climbing of dune sets due to local dominance of deposition over dune migration.Analysis of these new and published accounts of form-sets and their burial processes highlights that form-sets need not be indicative of extreme floods. Instead, form-sets are closely associated with surrounding geomorphology such as river banks, meander-neck cutoffs,and bars because this larger-scale context controls the local sediment budget and the nature of recurrence of erosion. Locally enhanced preservation by the ?extreme? dominance of deposition is further promoted by finer grain sizes and prolonged changes in flow stage. Such conditions are characteristic, although not exclusive, of large lowland rivers such as the RĂo ParanĂĄ. The spatial control on dune preservation is critical: although at-a-point models adequately describe near-horizontal sets of freely migrating dunes in uniform flows, they are unsuitable for inclined dune co-sets and other cases where multiple scales of bedforms interact. Spatial and temporal variations in flow and sediment transport betweenthe thalweg and different positions on larger bar-forms can change the preservation potential of dunes within river channels. Therefore, dune set thickness distributions are likely grouped in larger-scale units that reflect both formative dune geometries and bar-scale variations inpreservation potential. The multi-scale dynamics of preservation highlighted herein also provides a useful comparison for other sedimentary systemsFil: Reesink, Arnold J.. University Of Binghamton; Estados UnidosFil: Van den Berg, J. H.. University of Utrecht; PaĂses BajosFil: Parsons, Daniel R.. University Of Hull; Reino UnidoFil: Amsler, Mario Luis. Universidad Nacional del Litoral. Facultad de IngenierĂa y Ciencias HĂdricas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Best, James L.. University of Illinois. Urbana - Champaign; Estados UnidosFil: Hardy, Richard J.. University Of Durham; Reino UnidoFil: Orfeo, Oscar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste. Centro de EcologĂa Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de EcologĂa Aplicada del Litoral; ArgentinaFil: Szupiany, Ricardo Nicolas. Universidad Nacional del Litoral. Facultad de IngenierĂa y Ciencias HĂdricas; Argentin
Determination of Load Equivalency for Unpaved Roads
The load equivalency method is widely used to consider the effect of traffic loading on pavement design, and the equivalent axle load factor (EALF) for paved roads has been studied often. For unpaved roads, however, EALF is not well understood because it is not necessarily the same as it is for paved roads. In this study, cyclic plate load tests were conducted on unpaved road sections (six base-over-subgrade sections and four subgrade-only sections) constructed in a geotechnical box (2 m Ă 2.2 m Ă 2 m) to investigate the load equivalency for unpaved roads. The base-over-subgrade sections were constructed as unstabilized, T1 geogridâstabilized, and T2 geogridâstabilized base courses of 15% California bearing ratio (CBR) with thicknesses of 0.23 m and 0.30 m over weak subgrade of 2% CBR. The subgrade-only sections were constructed with CBR values of 6.2%, 7.4%, 9.5%, and 11.0%. The intensities of the cyclic loads were increased from 5 kN to 65 kN, at increments of 5 kN. For each load intensity, 100 cycles were applied on one test section. The EALFs were analyzed in terms of permanent deformation. The results showed that the regression powers of the ratios of axle loads for unpaved roads with aggregate bases over weak subgrade ranged from 1.9 to 2.9, which were lower than a power of 4, the typical value used for paved roads. The powers for subgrade-only sections had an even wider range, from 1.1 to 3.4. The increase of base thickness, the presence of geogrid, and the use of a higher-grade geogrid increased the power
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