8,943 research outputs found
Rapid detection and quantification of features such as damage or flaws in composite and metallic structures
An apparatus, system, and method for non-destructible evaluation (NDE) of a material use thermography to rapidly detect and/or generally locate a feature such as, for example, damage or a defect in the material. The apparatus, system, and method also use ultrasound to specifically locate the feature in the material for quantification and/or evaluation either by an operator or by an external device suited for such purpose. Accordingly, the apparatus, system and method are particularly useful for NDE in applications such as the analysis of the structure of an aircraft, for example, in which the scale of the material to be analyzed is large, thus requiring the rapid NDE afforded by thermography, and in which quantification and/or evaluation of a feature must be performed with precision, thus requiring the relatively high-resolution NDE afforded by ultrasound
Rumen function and digestion parameters associated with differences between sheep in methane emissions when fed chaffed lucerne hay
An indoor experiment involving 10 rumen-cannulated Romney sheep was conducted in May and June 1998 at AgResearch Grasslands, Palmerston North, New Zealand, under restricted feeding conditions. in order to test the hypothesis that animal factors, in particular rumen fractional outflow rate (FOR) and rumen volume, have an influence on the between-sheep variation in methane (CH4) emission. Sheep were fed 2-hourly on chaffed lucerne hay. Following an acclimatization period of 21 days, the experiment lasted 16 days. Energy and nitrogen (N) balances were measured on days 1-6. Cr-EDTA marker was continuously infused into the rumen from day 9 to 16, and rumen contents emptied and sampled on days 13 and 16. Particulate and fluid FOR were estimated using feed lignin and Cr-EDTA, respectively. Daily CH, production was measured by the sulphur hexafluoride tracer technique on days 2, 5, 6, 12 and 15 of the experiment.
CH4 production (g/day) was positively correlated with the pool size of organic matter (OM) in the rumen (OM pool, g) (r = 0.84, P = 0.002), OM intake (OMI, g/day) (r = 0.67, P = 0.04), and the rumen fill (g. wet digesta) (r = 0.76, P = 0.01). Multiple regression analysis showed that CH4 production was best predicted (R-2 = 0.88) as a function of OM pool and the molar % of butyrate; however, OM pool alone accounted for a large proportion (R-2 = 0.71) of the variation in CH4 production.
CH4 yield (% gross energy intake, % GEI) was negatively correlated with the particulate FOR (%/h) ( r= -0.75, P = 0.01) and buffering capacity of rumen fluid (mmol HCl) (r = -0.72, P = 0.02) but positively correlated with the digestibility of cellulose (r = 0.66, P = 0.04). Multiple regression analysis showed that CH, yield was best predicted as a function of particulate FOR, OMI (g/kg liveweight(0.75)) and the molar % of butyrate (R-2 = 0.88). Particulate FOR alone explained a large proportion (R-2 = 0.57) of the variation in CH4 Yield. Particulate FOR was negatively correlated with rumen fill (r = -0.69, P = 0.03) and digestibility of cellulose (r = -0.65, P = 0.04).
These results suggest that sheep with lower rumen particulate FOR (i.e. longer rumen retention times) had larger rumen fills and higher fibre digestibilities and CH4 yields. If rumen particulate FOR is to be used as a tool for CH4 mitigation, the repeatability of its relationship to CH4 emission must be assessed, preferably under grazing conditions
Persistence of differences between sheep in methane emission under generous grazing conditions
Four low and four high methane (CH4) emitters were selected from a flock of 20 Romney sheep on the basis of CH4 production rates per unit of intake, measured at grazing using the sulphur hexafluoride (SF,) tracer technique. Methane emissions from these sheep were monitored at grazing for four periods (P): October, November, January and February 1999/2000. All measurements were carried out on perennial ryegrass/white clover pasture under generous herbage allowance, and the sheep were maintained on similar pastures during non-measurement periods. The tracer technique was used for all the CH4 measurements and feed DM intake was calculated from total faecal collection and estimated DM digestibility. Data for liveweight (LW), gross energy intake (GEI) and CH4 emission were analysed using split-plot analysis of variance. In addition, a between-period rank order correlation analysis was carried out for CH4 emission data.
Low CH4 emitters were heavier (P < 0.05) than the high emitters in all the periods, but they did not differ (P < 0.05) in their gross energy intakes (GEL MJ/kg LW0.75). Low and high CH4 emitters consistently maintained their initial rankings in CH4 yield (% GEI) throughout the subsequent periods and the correlation analysis of rank order for CH4 yield showed strong between-period correlation coefficients, although this was weaker in the last period. It is suggested that feeding conditions that maximize feed intake (e.g. generous allowance of good quality pasture under grazing) favour the expression and persistence of between-sheep differences in CH4 yield
Agreement between methods of measurement with multiple observations per individual
Limits of agreement provide a straightforward and intuitive approach to agreement between different methods for measuring the same quantity. When pairs of observations using the two methods are independent, i.e., on different subjects, the calculations are very simple and straightforward. Some authors collect repeated data, either as repeated pairs of measurements on the same subject, whose true value of the measured quantity may be changing, or more than one measurement by one or both methods of an unchanging underlying quantity. In this paper we describe methods for analysing such clustered observations, both when the underlying quantity is assumed to be changing and when it is not
Plant Secondary Compounds; Their Impact on Forage Nutritive Value and upon Animal Production
Both the anti-nutritional and beneficial effects of secondary compounds in a range of temperate and tropical forages have been reviewed. Major secondary compounds in temperate and tropical forage plants occur in the phenolic fraction and include condensed and hydrolysable tannins, phenolic monomers and lignin. Condensed tannins (CT) bind to plant protein by pH-reversible hydrogen bonding. In temperate legume forages this reduces rumen protein degradation and can increase the absorption of essential amino acids (EAA) from the small intestine, with reactivity depending on CT concentration, molecular weight and chemical structure. Low concentrations of CT in Lotus corniculatus (20-40g/kg DM) increased EAA absorption by 62% and increased wool growth (15%) and ovulation rate (25%) in grazing sheep and increased milk production in ewes and dairy cows, all without changing voluntary feed intake (VFI). High concentrations of CT in Lotus pedunculatus (80- 100 g/kg DM) depressed VFI and depressed rates of body and wool growth in grazing sheep. Sulla, containing 80-120 g CT/kg DM, was particularly effective for counteracting the effects of parasitism and for promoting high rates of body growth in parasitised lambs. CT is present in tropical species such as Leucaena and Acacia at higher concentrations (60-200 g/kg DM) than in temperate species. Action of CT reduced rumen protein degradation in sheep fed tropical forages, but as yet there is no convincing evidence that this leads to increases in EAA absorption from the small intestine or that CT increases animal production. Further research is needed in these areas with tropical forages, particularly on the relationship between CT structure and its reactivity with proteins. Increasing CT concentration did not depress rumen microbial protein synthesis in sheep fed either temperate or tropical forages, until CT concentration exceeded 130 g/kg DM. Effect of CT upon undegraded, dietary protein release in the small intestine and upon endogenous protein secretion is defined as a future research area.
Flavonoids have been detected in tropical legume forages in the same concentrations as CT. They have anti-nutritional effects in terms of causing amino acid loss during their excretion as conjugates in the urine and by disturbing blood acid/base balance, leading to reduced VFI.
Research currently in progress with other secondary compounds in both temperate and tropical forages is reviewed. This includes sesquiterpene lactones in chicory, acubin in plantain, isoflavones in red clover and coumarin and dihydro-coumarin in glyricidia. The nutritional and anti-nutritional effects of these compounds for both ruminants and non-ruminants is discussed
Methane emission by alpaca and sheep fed on lucerne hay or grazed on pastures of perennial ryegrass/white clover or birdsfoot trefoil
Based on the knowledge that alpaca (Lama pacos) have a lower fractional outflow rate of feed particles (particulate FOR) from their forestomach than sheep (San Martin 1987), the current study measured methane (CH4) production and other digestion parameters in these species in three successive experiments (1, 2 and 3): Experiment 1, lucerne hay fed indoors; Experiment 2, grazed on perennial ryegrass/white clover pasture (PRG/WC); and Experiment 3, grazed on birdsfoot trefoil (Lotus corniculatits) pasture (Lotus). Six male alpaca and six castrated Romney sheep were simultaneously and successively fed on the forages either ad libitium or at generous herbage allowances (grazing). CH4 production (g/day) (using the sulphur hexafluoride tracer technique), voluntary feed intake (VFI), diet quality, and protozoa counts and volatile fatty acid concentrations in samples of forestomach contents were determined. In addition, feed digestibility, energy and nitrogen (N) balances and microbial N supply from the forestomach (using purine derivatives excretion) were measured in Experiment 1.
Diets selected by alpaca were of lower quality than those selected by sheep, and the voluntary gross energy intakes (GEI, MJ) per kg of liveweight(0.75) were consistently lower (P0.05) in their CH4 yields (% GEI) when fed on lucerne hay (5.1 v. 4.7), but alpaca had a higher CH4 yield when fed on PRG/WC (9.4 v. 7.5, P0.05) in diet N partition or microbial N yield, but alpaca had higher (P<0.05) neutral detergent fibre digestibility (0.478 v. 0.461) and lower (P<0.01) urinary energy losses (5.2 v. 5.8 % GEI) than sheep. It is suggested that differences between these species in forestomach particulate FOR might have been the underlying physiological mechanism responsible for the differences in CH4 yield, although the between-species differences in VFI and diet quality also had a major effect on it
Who is in the transition gap? Transition from CAMHS to AMHS in the Republic of Ireland
Objective: The ITRACK study explored the process and predictors of transition between Child and Adolescent Mental Health Services (CAMHS) and Adult Mental Health Services (AMHS) in the Republic of Ireland. Method: Following ethical approval, clinicians in each of Ireland's four Health Service Executive (HSE) areas were contacted, informed about the study and invited to participate. Clinicians identified all cases who had reached the transition boundary (i.e. upper age limit for that CAMHS team ) between January and December 2010. Data were collected on clinical and socio-demographic details and factors that informed the decision to refer or not refer to AMHS and case notes were scrutinised to ascertain the extent of information exchanged between services during transition
Comparative energetics and kinetics of autotrophic lipid and starch metabolism in chlorophytic microalgae: implications for biomass and biofuel production
A fourth account of centipede (Chilopoda) predation on bats
With an incident in Palo Duro Canyon, Texas, USA, Scolopendra heros Girard (Chilopoda: Scolopendromorpha: Scolopendridae) becomes the third centipede species known to prey on bats; S. gigantea Linnaeus and S. viridicornis Newport have been so documented in Venezuela and Brazil, respectively. The Texas predation was interrupted by the predator/prey pair’s falling around 15–20 m from the canyon wall and, perhaps also, by human presence where they landed. The centipede uncoiled and retreated to shelter under a nearby rock and, after initial immobilization, so did the bat.
Con un incidente en Palo Duro Canyon, Texas, Estados Unidos, Scolopendra heros Girard (Chilopoda: Scolopendromorpha: Scolopendridae) se convierte en el tercer ciempiés que se sabe depreda murciélagos; S. gigantea Linnaeus y S. viridicornis Newport han sido documentados mostrando este comportamiento en Venezuela y Brasil, respectivamente. El incidente de Texas fue interrumpido por el despeñamiento del par depredador/presa unos 15–20 m desde la pared del cañón y, al parecer, por la presencia humana en el sitio de caÃda. El ciempiés se desenrolló y retiró para refugiarse bajo una roca cercana. Tras permanecer inmóvil inicialmente, el murciélago hizo lo mismo
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