ABSTRACT
Mental health concerns are common among college students and more prevalent during examination periods when stress and anxiety are heightened. While the benefits of equine interaction have been reported, the impact of short-term equine interaction on coping skills valuable for managing test anxiety have yet to be studied. Therefore, the purpose of this preliminary study was to evaluate the impact of short-term equine interaction during the college examination period on development of coping skills and anxiety levels associated with testing, both self-reported and those reflected in physiological measures. Full-time college students engaged in a one-hour equine interaction session held on campus at the onset of final exam week. Participants completed a survey targeting perception of anxiety levels and coping skills. Heart rate and salivary cortisol measurements were collected pre- and post-session. Paired t-tests were performed between pre- and post- session measures and correlations between survey answers and physiological measures determined. Significant reductions were found in all areas of anxiety (Overall Academics P = 0.0003, Final Exam Preparation P = 0.0003, Taking Final Exam P = 0.0003). The reduction in exam-related anxiety was positively correlated to cortisol concentrations (r = 0.69, P = 0.03) with lower concentrations (P = 0.05) and increased heart rate (P = 0.003) post-session. Regarding coping skills, improvements were observed post-session in assertiveness (P = 0.008). Skill development coupled with reduced anxiety supports the potential benefits short-term equine interaction can offer students during the high stress periods, but these findings should be confirmed with more in-depth study.
Subject(s)
Coping Skills , Students , Adult , Animals , Female , Humans , Male , Young Adult , Anxiety/psychology , Heart Rate/physiology , Horses , Hydrocortisone/analysis , Hydrocortisone/metabolism , Saliva/chemistry , Saliva/metabolism , Students/psychology , Test Anxiety/metabolism , UniversitiesABSTRACT
Our study aimed to investigate responses to supplementation of calcium (Ca), magnesium (Mg) and sodium (Na) to lactating ewes and lambs grazing barley forage from lamb marking to weaning. A 10-ha paddock sown to barley was subdivided into eight plots as four replicates of two treatments. Merino ewes (n = 104) with lambs at foot were stratified to the eight plots (13 ewes and 21 lambs/plot) based on number of lambs (twin or single) and ewes' weight. Supplemented groups had access to mineral supplements (30 g/ewe/day) supplying 12 g/ewe/day ground limestone, 12 g/ewe/day Causmag® and 6 g/ewe/day coarse salt in a ratio of 2: 2: 1 by weight (as fed) from day 0 (a day before lamb marking) after sample collection. Control groups were not supplemented with minerals. Blood, milk and urine samples from ewes and blood from lambs were collected at different time points, namely, a day prior to lamb marking (day 0), 14 days after the commencement of study (day 14), and 28 days after the commencement of study (day 28). Weight of the lambs was also recorded at each time point. We found that the concentration of the forage minerals (Ca, Mg and potassium (K)) was lower on day 28 than on day 0 (P < 0.025). Liveweight gain was greater in the first 14 days compared with the second weight gain period (P < 0.001). The interaction of time and treatment was significant for liveweight (P < 0.001). Due to the improvement in weight gain of supplemented lambs, we recommend that mineral supplementation during late lactation is beneficial considering the low cost of minerals, even though the mineral content of the forage was not deficient.
Subject(s)
Animal Nutritional Physiological Phenomena , Calcium , Dietary Supplements , Lactation , Magnesium , Sodium , Animals , Female , Lactation/physiology , Minerals , Sheep , Sheep, Domestic , Weight GainABSTRACT
Retention of aging ewes is a strategy producers may use to maintain or increase flock size. Older ewes can have a higher risk of mortality and health issues, but these may be minimised with early intervention and culling. This retrospective study examined the incidence and causes of mortality and culling in a flock of Merino ewes as they aged from 4.5 to 5.5 until 9.5 to 10.5 years. The annual rate of ewe mortality ranged from 6.2% to 9.9%, with lambing complications being the major source of reported loss. Annual culling rates ranged from 1.6% to 42.8%, the larger rates reflecting opportunistic replacement with younger ewes rather than essential culling to maintain welfare and productivity. The major reasons for culling were low condition score, worn or missing teeth or faulty udders. The incidence of other faults was low. Only 18.3% of ewes remained when aged 9.5-10.5 years and these were fertile (89% pregnant) with a high proportion of multiple fetuses (52%) in their final year, although fleece weight had declined. Younger ewes born in 2004/2005 tended to have lower annual mortality rates than the aged ewes, but 8%-12% were still culled annually. It is concluded that an annual inspection pre-joining of all ewes and preventative culling for health issues is necessary to minimise any increase in mortality and risk to ewe welfare from retaining aging ewes. More frequent inspection will be required as potential health issues develop during the year, as these may not be evident pre-joining.
Subject(s)
Aging , Fertility , Pregnancy , Sheep , Animals , Female , Retrospective Studies , Sheep, DomesticABSTRACT
PURPOSE: Access and affordability of hearing health care varies depending on residency and individual financial means. Those living in rural areas have limited health care resources and experience higher levels of poverty compared to those living in urban regions. The purpose of this study was to determine the feasibility of interprofessional collaboration among physicians and audiologists and pharmacists and audiologists to improve access and affordability of hearing health care in rural communities. METHOD: Sixteen family physicians and medicine residents and 15 community pharmacists participated in the study. Physicians and residents completed an online survey to assess education regarding hearing health care and their understanding of hearing loss intervention. They also participated in small virtual focus group discussions. Pharmacists participated in virtual discussions based on guided questions. RESULTS: The discussions with both physicians and pharmacists highlighted the need for more education, resources, and awareness of the negative impact of hearing loss on overall quality of life. Comments from these discussions were placed within the socio-ecological model of health behavior to increase understanding of hearing health behavior. CONCLUSIONS: Increased collaboration among medical professionals has the potential to improve access to hearing health care for those living in audiologically underserved regions of the country. Further research will identify how to increase effective and sustainable hearing health care resources in rural communities.
Subject(s)
Audiology , Hearing Loss , Pharmacy , Alabama , Audiology/education , Delivery of Health Care , Hearing , Humans , Quality of Life , Rural PopulationABSTRACT
Containment feeding, where ewes are fed complete rations, is used to maintain flock numbers in periods of inadequate pasture supply. Producer practices influence both the reproductive performance of ewes and the risk of health challenges. The aim of this study was to evaluate the reproductive, feeding and health management practices of producers using containment or supplementary feeding, and quantify any associations between practice and reproductive performance. An online survey of Australian producers was conducted in 2020. The number of responses (n = 43) allowed benchmarking but was insufficient to determine correlations between practice and performance. The reported pregnancy rate of adult Merino ewes was variable between respondents (78%-95%; n = 11), and lambs marked per ewe joined ranged from 60% to 110% (n = 9). In non-Merino flocks, lambs marked ranged from 82% to 161% (n = 4). Most respondents (9/11) fed cereal grain with hay or straw, either daily or two or three times a week. However, some respondents fed grain only or roughage only, such that the percentage of roughage in diets ranged from 0% to 100%. Ewes were most frequently separated into age groups for feeding, and shy feeders were only removed by 25% of respondents. Although generally the reported reproductive rate was high, wide variation indicates potential for improvement. Best practice management for containment remains unclear and requires further research given the diverse practices used. Veterinary practitioners should be aware that some of the practices used may contribute to reduced productivity or health issues in ewes.
Subject(s)
Diet , Reproduction , Animals , Australia , Female , Pregnancy , Pregnancy Rate , Sheep , Surveys and QuestionnairesABSTRACT
Perinatal mortality of lambs is the major source of reproductive loss in extensive sheep production systems. Treatment with caffeine has reduced intra-partum mortality and/or improved metabolic indicators in other species following hypoxia. This study was conducted to evaluate the efficacy of caffeine for improving perinatal lamb survival. Experiment 1 comprised group-fed Merino ewes grazing pasture and offered 1.8 g/day (estimated 20 mg/kg live weight) caffeine throughout a 4-week lambing period, and a control without caffeine. The survival of lambs to marking (vaccinated, tail docked, males castrated) age in the caffeine treatment group (0.81) did not differ (P = 0.199) from that of control lambs (0.73; total born n = 877). Experiment 2 comprised Merino ewes lambing from three successive weekly joining groups. Treated ewes were drenched with an aqueous caffeine solution at a dose rate of 10 mg/kg live weight from the day before anticipated lambing, until the individual lambed. Control ewes were drenched with water. The proportion of lambs born dead (0.07) and the survival of lambs to marking age (caffeine 0.61; control 0.62) were similar between treatment groups (total born n = 1158). In both experiments, ewe mortality and the weight of lambs at marking were not altered by caffeine treatments. The results from this large-scale field study indicate caffeine is not an effective therapeutic agent to increase either intra-partum or perinatal survival, or lamb growth rates.
Subject(s)
Caffeine/pharmacology , Central Nervous System Stimulants/pharmacology , Dystocia/veterinary , Sheep/physiology , Administration, Oral , Animals , Animals, Newborn/physiology , Caffeine/administration & dosage , Central Nervous System Stimulants/administration & dosage , Female , Male , PregnancyABSTRACT
Correct diagnosis of cause of death is necessary to suggest the most effective management interventions to reduce perinatal lamb mortality. Haemorrhage on the surface of the brain has been used as a field diagnostic tool to allocate lambs to a cause of death category, but the usefulness of this method was unclear. This study aimed to evaluate whether gross pathology was related to neuronal death and whether haemorrhage of the central nervous system (CNS) was distinct between differing causes of death, enabling indicators to be used in field diagnoses. Lambs dying from natural causes (n = 64) and from euthanasia (n = 7) underwent postmortem examination, then the brain and spinal cord were extracted and examined histologically. Histological changes consistent with neuronal death were not detected in any lamb. Haemorrhage of the meninges and/or parenchyma of the CNS occurred in all lambs. The age of the haemorrhage indicated that it occurred near the time of death in most lambs. Dilation of blood vessels varied in severity but appeared to be unrelated to causal diagnosis, severity of subcutaneous oedema, breathing or milk status. Moderate or severe dilation of blood vessels and haemorrhage of the CNS did not occur in all lambs with alternative clear indicators of dystocia and occurred in all death classifications, so it could not be used as diagnostic indicators for classification of cause of death. Dilation and haemorrhage were unrelated to neuronal damage and may have been artefactual. In conclusion, haemorrhage of the CNS was not indicative of neuronal damage and could not be used to distinguish between lambs with clear indicators of differing causes of death, so it is not recommended as a field diagnostic tool.
Subject(s)
Dystocia , Sheep Diseases , Animals , Animals, Newborn , Central Nervous System , Dystocia/veterinary , Female , Pregnancy , Sheep , Sheep Diseases/diagnosis , Sheep, DomesticABSTRACT
Perinatal mortality of lambs is on average 20% of lambs born in extensive Australian grazing systems, constituting a substantial production loss and welfare concern. Hypoxia resulting from prolonged or difficult births contributes to lower rates of lamb survival, and caffeine may reduce the effects of hypoxia. This study evaluated whether oral supplementation of grazing ewes with caffeine could improve lamb survival. Pregnant Merino ewes (n=492) which had been naturally mated to Merino rams in February/March were allocated to three replicates of control (no caffeine) or caffeine treatments. Caffeine was fed daily in troughs in each paddock at a rate of 1.6 g/ewe per day (estimated at 20 mg/kg live weight) from the day before the first lamb was born, for 14 days, with lambing continuing for 6 weeks. Intake was facilitated using 320 g/day per ewe of barley grain with molasses, which was fed to both treatments. The proportion of lambs born alive during the period of supplementation did not differ (P>0.05) between treatments. The proportion mortality of lambs to 1 day of age was lower (P=0.029) in the caffeine (0.01) compared with the control (0.16) treatment for lambs born during the 1st week of supplementation, but not in later weeks. This difference in mortality for lambs born in the 1st week of supplementation was maintained to marking age (caffeine 0.09; control 0.30; P=0.027). Extreme weather during the 2nd week of supplementation may have prevented any reduction in mortality due to caffeine in that week. Feeding caffeine to a naturally lambing flock of grazing ewes may be a highly effective and commercially practical method of increasing lamb survival, but further research is needed to confirm these results, and caffeine be regulated for use.
Subject(s)
Caffeine/pharmacology , Sheep/physiology , Animals , Australia , Female , Male , Parturition/drug effects , Pregnancy , Random AllocationABSTRACT
The internal structure of nucleons (protons and neutrons) remains one of the greatest outstanding problems in modern nuclear physics. By scattering high-energy electrons off a proton we are able to resolve its fundamental constituents and probe their momenta and positions. Here we investigate the dynamics of quarks and gluons inside nucleons using deeply virtual Compton scattering (DVCS)-a highly virtual photon scatters off the proton, which subsequently radiates a photon. DVCS interferes with the Bethe-Heitler (BH) process, where the photon is emitted by the electron rather than the proton. We report herein the full determination of the BH-DVCS interference by exploiting the distinct energy dependences of the DVCS and BH amplitudes. In the regime where the scattering is expected to occur off a single quark, measurements show an intriguing sensitivity to gluons, the carriers of the strong interaction.
ABSTRACT
We report the first longitudinal-transverse separation of the deeply virtual exclusive π^{0} electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσ_{L}/dt, dσ_{T}/dt, dσ_{LT}/dt, and dσ_{TT}/dt are extracted as a function of the momentum transfer to the recoil system at Q^{2}=1.75 GeV^{2} and x_{B}=0.36. The edâedπ^{0} cross sections are found compatible with the small values expected from theoretical models. The enâenπ^{0} cross sections show a dominance from the response to transversely polarized photons, and are in good agreement with calculations based on the transversity generalized parton distributions of the nucleon. By combining these results with previous measurements of π^{0} electroproduction off the proton, we present a flavor decomposition of the u and d quark contributions to the cross section.
ABSTRACT
A significant number of lambs born each yr in Australia die within 72 h of birth. Periods of high wind, combined with rain and low temperatures, can lead to marked increases in the level of mortality. Under these weather conditions mortality levels may be reduced with the provision of shelter, provided it is utilized by lambs. This study used GPS collars to determine the use of shelter by ewes and lambs, to compare the movement of ewes with twin lambs across 2 types of shelter (hedgerows and shrubs), while also comparing ewes with single and twin lambs in a single shelter type (hedgerows). Additionally, the birth sites of 364 lambs and death sites of 252 lambs were recorded across the 3 shelter type and litter size combinations (Twins in shrubs, Twins in hedgerows, Singles in hedgerows) plus an unsheltered group (Singles in unsheltered). A higher (P < 0.001) than randomly expected percentage of ewes lambed in the areas closest to both shelter types; in the shrub shelter 42% of ewes lambed within 2.5 m of shrub rows compared to an expected 11% based on the proportion of the paddock this area constituted. Despite the higher than expected percentage of ewes lambing close to the shelter rows, ewes in both twin lamb shelter types avoided the areas close to the shelter before and after lambing (Hedgerows-2.5 m; Shrubs- 6.25 m) and single bearing ewes showed no preference for or against these areas. With a high proportion of twin bearing ewes lambing close to the shelter, a design that reduces the potential for ewe and offspring separation while providing good shelter will offer the greatest potential reduction in newborn twin lamb mortality arising from exposure.
Subject(s)
Parturition , Sheep/physiology , Animals , Animals, Newborn , Australia , Behavior, Animal , Female , Housing, Animal , Litter Size , MovementABSTRACT
We present deeply virtual π^{0} electroproduction cross-section measurements at x_{B}=0.36 and three different Q^{2} values ranging from 1.5 to 2 GeV^{2}, obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σ_{LT}. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q^{2} regime.
ABSTRACT
High intake of lucerne pastures or feeding of other high quality diets during early pregnancy may increase embryo mortality, negating any benefit of improved nutrition on ovulation rate in ewes. This study was conducted to determine whether grazing ewes on lucerne (Medicago sativa) pastures for 7 days prior to and throughout joining would result in greater foetal numbers than if ewes were removed 7 days after the commencement of joining, or if ewes grazed senescent pasture throughout the joining period. Merino ewes (300) were allocated to two replicates of three treatments, grazing pastures between Days -7 and 36 of an unsynchronised, natural autumn joining. Grazing lucerne to Day 7 of joining resulted in 30% more (P<0.05) foetuses per ewe than grazing senescent pasture (1.60±0.07 and 1.31±0.07, respectively), and 19% more lambs marked per ewe joined. Extending grazing of lucerne past Day 7 of joining did not result in additional foetuses per ewe (1.61±0.06) in comparison with only grazing lucerne to Day 7 of joining. Greater than 80% of ewes mated during the first 14 days of joining, and the proportions of ewes returning to oestrus and re-mating (0.18±0.022) and of non-pregnant (0.09±0.017) ewes were similar (P>0.05) among all treatment groups, suggesting no differences between treatments in embryo mortality. Grazing naturally cycling ewes on lucerne prior to and during joinings in autumn is recommended as a means to increase the number of lambs born, although additional gains may not be obtained by grazing past day seven of joining.
Subject(s)
Diet/veterinary , Medicago sativa , Reproduction/physiology , Sheep/physiology , Animals , Female , Pregnancy , Pregnancy Outcome/veterinaryABSTRACT
Feeding ewes a diet high in n-6 in late gestation can affect fatty acid concentrations in the newborn lamb. The effect of feeding ewes a high n-6 diet prior to conception and in early gestation on lamb n-6 and n-3 status has not previously been examined. The aim of the current study was to determine whether the concentration of n-6 was higher and n-3 was lower in lamb red blood cells (RBC) and plasma when Merino dams were fed a diet high in n-6 either pre-conception only or both pre-conception and in early gestation. Dams were fed a diet low (silage) or high (oats/CSM) in n-6 for either 6 weeks pre-mating only or 6 weeks pre-mating and 17 days post-mating. The fatty acid status of lamb RBC and plasma was determined following birth and compared with dam fatty acids around parturition. The concentration of lamb RBC and plasma n-3 was lower (p < 0.05) when dams received the high n-6 compared with low-n-6 diet around mating, independent of the length of time of feeding. The concentration of n-3 in lamb plasma was also higher when lambs were assessed as being likely rather than unlikely to have suckled prior to blood collection. Lamb RBC and plasma n-3 fatty acids were lower when dams were fed the high compared with the low n-6 diet for only a short time around mating. Transfer of fatty acids via the placenta and milk may account for the differences.
Subject(s)
Diet , Erythrocytes/metabolism , Fatty Acids, Omega-3/blood , Fatty Acids, Omega-6/blood , Animals , Animals, Newborn , Female , Pregnancy , Reproduction , SheepABSTRACT
Elevated intakes of protein and energy may increase embryo mortality, but it is not clear whether fresh lucerne (Medicago sativa) pasture poses a risk. A two-year pen study using oestrous synchronised and artificially inseminated Merino ewes (n=175 in 2013 and 215 in 2014) evaluated whether feeding freshly cut lucerne pasture (mean crude protein 19.7%, metabolisable energy 9.4MJ/kg DM) at maintenance or ad libitum during different periods around insemination altered reproductive performance in comparison with ewes fed a Control diet (mean crude protein 7.8%, metabolisable energy 9.0MJ/kg DM) of pelleted faba bean hulls and oat grain hulls at maintenance. The proportion of pregnant ewes carrying multiple fetuses was reduced (P=0.026) when ewes were fed lucerne ad libitum between days 0 and 17 after insemination compared with the Control diet (0.18 and 0.34, respectively), but not when ewes were fed lucerne ad libitum between days 0 and 7 after insemination (0.22). Reproductive performance, including the proportion of ewes pregnant and the proportion with multiple fetuses, was not different (P>0.05) when ewes were fed lucerne at maintenance between days 0 and 7 compared with the Control diet. While reproductive performance was similar when ewes were fed lucerne at maintenance between 0 and 17 days after artificial insemination compared with pellets at maintenance, fetal numbers per pregnant ewe were reduced by feeding lucerne ad libitum after insemination.
Subject(s)
Animal Feed/analysis , Medicago sativa , Sheep/physiology , Animal Nutritional Physiological Phenomena , Animals , Diet/veterinary , Female , Fertility , Insemination, Artificial/veterinary , Litter Size , PregnancyABSTRACT
Two experiments were conducted to assess preference by sheep for endophyte-infected tall fescue growing in monoculture at least 5 m away from alfalfa (fescue-middle (FM)) over endophyte-infected tall fescue growing adjacent (0.2 to 1 m; fescue-alfalfa (FA)) to alfalfa (FA), and the effect of legume scent on preference for endophyte-infected tall fescue. In Experiment 1, 10 six-month-old lambs were offered for 12 days a choice of freshly harvested FA and FM. On days 13 and 14, lambs were offered the same choice, except cages (to allow access only to scent) containing freshly harvested alfalfa were put in the feeders containing FA, whereas cages containing freshly harvested FM were included with the feeders containing FM. Forage intake was measured 1 h after feeding and at three consecutive 2-h intervals thereafter. FA contained greater (P<0.002) concentrations of the alkaloid ergovaline (360 ± 27 ppm) and CP (8 ± 0.4%) than FM (219 ± 27 ppm and 6 ± 0.4%, respectively). Lambs preferred (P<0.05) FA to FM during the 1st hour of feeding, but the differences became smaller and disappeared in later feeding periods (P<0.005). Lambs offered FA with alfalfa scent or FM with FM scent preferred (P<0.05) FA but only on the 2nd day. In Experiment 2, 10 six-month-old lambs were offered a choice of FM with cages (to allow access only to scent) containing freshly harvested alfalfa or FM for 8 days. During the following 4 days, FM in the cages was replaced with freshly harvested sainfoin. Preference was greater (P<0.05) for FM offered with alfalfa scent than for FM offered with FM scent only on days 4 and 8. When lambs were offered FM with alfalfa or sainfoin in cages, they preferred (P<0.05) tall fescue with sainfoin scent over fescue with alfalfa scent, but intake was variable across hours and days (P<0.001). It is concluded that (1) lambs adjusted their intake of and preference for FA and FM over successive feeding bouts within each day, likely owing to an attempt to balance intakes of nutrients and alkaloids and (2) olfactory cues influenced preference, but to a lesser extent than nutrients and alkaloids in endophyte-infected tall fescue.
Subject(s)
Animal Nutritional Physiological Phenomena , Endophytes/chemistry , Festuca/growth & development , Food Preferences/physiology , Medicago sativa/growth & development , Sheep, Domestic/physiology , Animals , Ergotamines/analysis , Festuca/microbiology , Models, Statistical , Odorants/analysis , Sheep , Time FactorsABSTRACT
Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.
ABSTRACT
We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond â¼500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.
ABSTRACT
We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.
ABSTRACT
The principles of domestic herbivore nutrition are well understood and have been developed through detailed physiological studies, although methods to accurately measure field-based intake still challenge herbivore nutrition research. Nutritional ecology considers an animal's interaction with the environment based on its nutritional demands. Although there are a number of theoretical frameworks that can be used to explore nutritional ecology, optimal foraging provides a suitable starting point. Optimal foraging models have progressed from deterministic techniques to spatially explicit agent-based simulation methods. The development of optimal foraging modelling points towards opportunities for field-based research to explore behavioural preferences within studies that have an array of nutritional choices that vary both spatially and temporally. A number of techniques including weighing animals, weighing herbage, using markers (both natural and artificial) and sampling forage, using oesophageal-fistulated animals, have been used to determine intake in the field. These intake measurement techniques are generally most suited to studies that occur over a few days and with relatively small (often less than 10) groups of animals. Over the last 10 years, there have been a number of advances in automated behavioural monitoring technology (e.g. global positioning systems) to track animal movement. A number of recent studies have integrated detailed spatial assessments of vegetation using on-ground sampling and satellite remote sensing; these data have been linked to behavioural preferences of herbivores. Although the recent studies still do not address nutritional interactions over months or years, they do point to methods that could be used to address landscape scale nutritional interactions. Emerging telemetry techniques used to monitor herbivore behavioural preferences and also to determine detailed landscape vegetation mapping provide the opportunity for future herbivore nutritional ecology studies.