Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 161
Filtrar
1.
J Dairy Sci ; 104(7): 7856-7870, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33896637

RESUMEN

Spray-dried plasma protein (SDP) has been shown to improve growth and intestinal function in young calves when included in milk replacers (MR) fed at conventional rates. Use of an SDP and wheat protein blend to replace a portion of whey protein has been shown to perform similarly to using an all-whey protein control MR. However, a trend in the dairy industry is to feed calves for greater rates of growth during the preweaning period. The purpose of this study was to determine the effects of increasing amounts of SDP inclusion in MR on growth and health of calves fed at a high plane of nutrition. Young (<7 d) Holstein calves were offered starter and assigned to 1 of 5 MR treatments: an all-milk protein (whey) control MR (0SDP, n = 26) or MR containing 5% SDP (5SDP, n = 20), 7.5% SDP (7.5SDP, n = 14), 10% SDP (10SDP, n = 20), or 12% of an approximate 1:1 SDP plus wheat protein blend (PW, n = 17). All MR were formulated to contain 26% CP and 16% fat and were fed at a maximum rate of 1 kg of powder (as fed) from d 8 to 36. Amounts of MR powder were decreased by 25%/wk from d 37 to weaning at d 57. Thereafter, calves were provided only starter feed until the end of the study at d 63. On d 4, 15, 36, and 57, intestinal permeability was assessed via oral administration of lactulose and d-mannitol followed by analysis of lactulose and mannitol in blood at 60 min after administration. Increasing SDP led to a small linear decrease in MR consumed. There was a tendency for a positive linear relationship between increasing SDP and average daily gain of body weight, and SDP had mixed effects on body frame variables. Increasing SDP tended to increase fecal scores and increased the amount of fluid therapy given. Diet had no effect on intestinal permeability. Increasing SDP led to an increase in serum total cholesterol and serum urea N and tended to have a quadratic effect on serum glucose concentration on d 36. Calves fed PW tended to have increased withers height, increased intestinal permeability on d 36, and an increased likelihood of being medicated for any reason or being medicated for respiratory illness, but growth and health were not different from the control diet otherwise. Feeding PW led to an increase in serum total cholesterol and tended to lead to increased serum glucose concentration on d 36. Results of this study indicate that SDP can be included at up to 10% as fed in the MR of calves fed at a high plane of nutrition (1 kg/d of MR powder, as fed) with improvements in average daily gain. Additionally, a 1:1 SDP plus wheat protein blend can be used at 12% inclusion with no difference in most health and growth parameters.


Asunto(s)
Alimentación Animal , Leche , Alimentación Animal/análisis , Animales , Proteínas Sanguíneas , Peso Corporal , Bovinos , Dieta/veterinaria , Morbilidad , Permeabilidad , Destete
2.
J Dairy Sci ; 102(8): 7183-7188, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31202645

RESUMEN

The objective of this study was to evaluate the effects of incorporating 2 commonly used additives or spray-dried porcine plasma in calf milk replacer (CMR) on calf performance and health. Male Holstein calves (n = 158) transported from auction barns and local dairy farms were randomly assigned to receive 1 of 3 decoquinate-containing CMR for the first 49 d of the experiment: all milk protein and no additives (CONT); 15% of crude protein (CP) replaced with spray-dried porcine plasma, no additives (PLM); or all milk protein and an added combination of sodium butyrate (rate 1.4 kg of butyric acid/Mt) and Bacillus subtilis (1.28 million cfu/g of feed; BB). All milk replacers were formulated to contain 26% CP and 17% fat, 2.4% Lys, and 0.8% Met, and were bucket-fed at daily feeding rates of 520 g during wk 1 and 2, 650 g during wk 3, and 900 g during wk 4 and 5, in a total of 4, 5, and 6 L of solution, respectively. Calves were offered texturized calf starter (18% CP) upon arrival until wk 3 and transitioned to a corn and pellet ration with 2% straw (18.1% CP). No prophylactic administration of antibiotics occurred. All calves were gradually weaned over a 2-wk period. Calves were individually housed until weaned and then housed in groups of 5 in a mechanically ventilated facility in southwestern Ontario, Canada. Fecal scores, treatments administered (antibiotic or supportive therapy), and mortalities were recorded daily. Body weight was measured using a digital scale at arrival and at 14, 49, 56, and 78 d after arrival. No differences were found among the groups with respect to growth, feed efficiency, or incidence of diarrhea or respiratory infection treatment. Calves supplemented with BB had a greater hazard of mortality over the growing period compared with CONT. An interaction was found between the BB group and the level of total serum protein, with the BB group having a lower proportion of days with a fecal score of 3 when the calves had a higher total serum protein level. Calves fed PLM had a lower proportion of d with a fecal score of 3 relative to CONT but no difference in the proportion of d with a fecal score of 2 or higher. This study found that the addition of spray-dried plasma in CMR reduced diarrhea severity; however, supplementing BB was associated with a higher hazard of calf mortality and had a varying response on fecal score.


Asunto(s)
Alimentación Animal/análisis , Bacillus subtilis , Ácido Butírico/administración & dosificación , Bovinos/fisiología , Suplementos Dietéticos , Animales , Peso Corporal , Bovinos/crecimiento & desarrollo , Dieta/veterinaria , Masculino , Proteínas de la Leche/administración & dosificación , Sustitutos de la Leche/administración & dosificación , Ontario , Plasma , Distribución Aleatoria , Porcinos , Zea mays
3.
Phys Rev Lett ; 121(3): 032301, 2018 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-30085817

RESUMEN

We report measurements of the nuclear modification factor R_{CP} for charged hadrons as well as identified π^{+(-)}, K^{+(-)}, and p(p[over ¯]) for Au+Au collision energies of sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-p_{T} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP} at high p_{T} does depend on the collision energy, neither the proton nor the antiproton R_{CP} at high p_{T} exhibit net suppression at any energy. A study of how the binary collision-scaled high-p_{T} yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.

5.
Phys Rev Lett ; 120(6): 062301, 2018 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-29481217

RESUMEN

Rapidity-odd directed-flow measurements at midrapidity are presented for Λ, Λ[over ¯], K^{±}, K_{s}^{0}, and ϕ at sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV in Au+Au collisions recorded by the Solenoidal Tracker detector at the Relativistic Heavy Ion Collider. These measurements greatly expand the scope of data available to constrain models with differing prescriptions for the equation of state of quantum chromodynamics. Results show good sensitivity for testing a picture where flow is assumed to be imposed before hadron formation and the observed particles are assumed to form via coalescence of constituent quarks. The pattern of departure from a coalescence-inspired sum rule can be a valuable new tool for probing the collision dynamics.

6.
Lett Appl Microbiol ; 67(5): 442-448, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30152866

RESUMEN

The objectives of this study were to assess the effectiveness of an ultraviolet (UV-C, 254 nm) irradiation system and the spray-drying method as two independent safety steps on inactivation of Escherichia coli K88 and K99 spiked in porcine plasma at 6·46 ± 0·04 log10  ml-1 and 6·78 ± 0·67 log10  ml-1 respectively for UV-C method, and at 7·31 ± 0·39 log10  ml-1 and 7·66 ± 0·11 log10  ml-1 , respectively for the spray-drying method. The UV-C method was performed at different UV light doses (from 750 to 9000 J l-1 ) using a pilot plant UV-C device working under turbulent flow. Spray-drying treatment was done at inlet temperature 220 ± 1°C and two different outlet temperatures, 80 ± 1°C or 70 ± 1°C. Results indicated that UV-C treatment induced a 4 log10 viability reduction for both E. coli at 3000 J l-1 . Full inactivation of both E. coli strains was achieved in all spray-dried samples dehydrated at both outlet temperatures. The special UV-C system design for turbid liquid porcine plasma is a novel treatment that can provide an additional redundant biosafety feature that can be incorporated into the manufacturing process for spray-dried animal plasma. SIGNIFICANCE AND IMPACT OF THE STUDY: The safety of raw materials from animal origin such as spray-dried porcine plasma (SDPP) may be a concern for the swine industry. Ultraviolet treatment at 254 nm (UV-C) of liquid plasma has been proposed as an additional biosafety feature in the manufacturing process of SDPP. We found that UV-C exposure in the liquid plasma at 3000 J l-1 reduces about 4 log10 ml-1 for E. coli K88 and K99. Full inactivation of both E. coli strains was achieved in all spray-dried samples. The incorporation of UV-C treatment to liquid plasma improves the robustness of the SDPP manufacturing process.


Asunto(s)
Alimentación Animal/microbiología , Escherichia coli Enterotoxigénica/crecimiento & desarrollo , Rayos Ultravioleta , Animales , Desecación , Plasma/microbiología , Porcinos/sangre , Enfermedades de los Porcinos/microbiología , Enfermedades de los Porcinos/prevención & control
7.
Lett Appl Microbiol ; 67(2): 205-211, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29889981

RESUMEN

The objective of this study was to determine the effectiveness of the spray-drying process on the inactivation of Salmonella choleraesuis and Salmonella typhimurium spiked in liquid porcine plasma and to test the additive effect of immediate postdrying storage. Commercial spray-dried porcine plasma was sterilized by irradiation and then reconstituted (1:9) with sterile water. Aliquots of reconstituted plasma were inoculated with either S. choleraesuis or S. typhimurium, subjected to spray-drying at an inlet temperature of 200°C and an outlet temperature of either 71 or 80°C, and each spray-drying temperature combinations were subjected to either 0, 30 or 60 s of residence time (RT) as a simulation of residence time typical of commercial dryers. Spray-dried samples were stored at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days. Bacterial counts of each Salmonella spp., were completed for all samples. For both Salmonella spp., spray-drying at both outlet temperatures reduced bacterial counts about 3 logs at RT 0 s, while there was about a 5·5 log reduction at RT 60 s. Storage of all dried samples at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days eliminate all detectable bacterial counts of both Salmonella spp. SIGNIFICANCE AND IMPACT OF THE STUDY: Safety of raw materials from animal origin like spray-dried porcine plasma (SDPP) may be a concern for the swine industry. Spray-drying process and postdrying storage are good inactivation steps to reduce the bacterial load of Salmonella choleraesuis and Salmonella typhimurium. For both Salmonella spp., spray-drying at 71°C or 80°C outlet temperatures reduced bacterial counts about 3 log at residence time (RT) 0 s, while there was about a 5.5 log reduction at RT 60 s. Storage of all dried samples at either 4.0 ± 3.0°C or 23.0 ± 0.3°C for 15 days was effective for eliminating detectable bacterial counts of both Salmonella spp.


Asunto(s)
Desecación , Plasma/microbiología , Salmonella typhimurium/crecimiento & desarrollo , Enfermedades de los Porcinos/microbiología , Animales , Recuento de Colonia Microbiana , Calor , Porcinos
8.
J Dairy Sci ; 101(7): 6019-6031, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29605308

RESUMEN

Spray-dried plasma protein (SDP) compared with blood meal (BM) may contain various functional and active components that may benefit animal health. The objective of this experiment was to investigate the effects of feeding SDP or BM on production and blood profile in dairy cows during the transition and early-lactation periods. Seventy-two Holstein cows at 14 d before calving were used in a randomized block design. During the prepartum period, cows were fed a typical late-gestation diet containing BM (100 g/cow per day; 100BM, n = 24) or SDP (100 g/cow per day; 100SDP; n = 48). After calving, cows that were fed BM prepartum were fed a typical lactation diet formulated to provide 100 g/d of BM (100BM). Half the cows that were fed 100SDP prepartum were fed a lactation diet formulated to provide 100 g/d of SDP (100SDP; n = 24), and half were fed a diet formulated to provide 400 g/d of SDP (400SDP; n = 24) on a dry matter basis where SDP replaced BM (100SDP) or BM and soybean products (400SDP). All diets were balanced for crude protein concentration and metabolizable protein supply assuming BM and SDP were equal in rumen-degradable protein and rumen-undegradable protein. All data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC) as a randomized block design where contrasts were made for 100BM versus 100SDP for prepartum variables and 100BM versus 100SDP and 100SDP versus 400SDP for postpartum variables. Prepartum supplementation of SDP had no effect on plasma fatty acids and ß-hydroxybutyrate (2 d before calving). Plasma fatty acids (255 ± 29 µEq/mL) and ß-hydroxybutyrate (675 ± 70 µmol/L) at 8 and 14 d of lactation were not affected by SDP in the diet. Feeding SDP at 100 g/d compared with 100BM increased or tended to increase milk fat, protein, and lactose contents for 16 wk after parturition. Providing SDP at 400 g/d in the diet increased milk yield (42 vs. 39 kg/d), energy-corrected milk (44 vs. 41 kg/d), energy-corrected milk per kilogram of dry matter intake, and yields of milk fat (1.60 vs. 1.48 kg/d), protein (1.21 vs. 1.16 kg/d), and lactose compared with 100SDP. Body weight losses tended to be lower for 100SDP compared with 100BM without a difference between 100SDP and 400SDP. Plasma histidine concentration (d 14 of lactation) was lower for SDP compared with 100BM. In addition, plasma 1-methyl-l-histidine tended to be lower as inclusion rate of SDP increased. In conclusion, SDP at 400 g/d increased milk and milk component yields without an increase in feed intake. Studies evaluating effects of functional and active compounds in SDP on gut microbiome, gut health, and immune functions may be needed to determine mode of action.


Asunto(s)
Proteínas Sanguíneas/farmacología , Bovinos , Dieta/veterinaria , Lactancia/efectos de los fármacos , Alimentación Animal , Animales , Proteínas Sanguíneas/administración & dosificación , Femenino , Lactancia/fisiología , Leche , Rumen
9.
Pharmacogenomics J ; 17(1): 21-28, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27503581

RESUMEN

Irinotecan chemotherapy toxicities can be severe, and may result in treatment delay, morbidity and in some rare cases death. This systematic review of systematic reviews synthesises all meta-analyses on biomarkers for irinotecan toxicity across all genetic models for Asians, Caucasians, low dose, medium/high dose and regimens with and without fluorouracil. False-positive findings are a problem in pharmacogenetics, increasing the importance of systematic reviews. Four systematic reviews that investigated the effect of the polymorphisms UGT1A1*6 and/or*28 on neutropenia or diarrhoea toxicity were included. Both UGT1A1*6 and *28 were reliably demonstrated to be risk factors for irinotecan-induced neutropenia, with tests for both polymorphisms potentially being particularly useful in Asian cancer patients. UGT1A1*6 and *28 were also related to diarrhoea toxicity; however, at low doses of irinotecan there was evidence that UGT1A1*28 was not. In synthesising the best available evidence, this umbrella systematic review provides a novel reference for clinicians applying personalised medicine and identifies important research gaps.


Asunto(s)
Antineoplásicos Fitogénicos/efectos adversos , Camptotecina/análogos & derivados , Diarrea/genética , Glucuronosiltransferasa/genética , Metaanálisis como Asunto , Neutropenia/genética , Farmacogenética , Variantes Farmacogenómicas , Polimorfismo de Nucleótido Simple , Revisiones Sistemáticas como Asunto , Camptotecina/efectos adversos , Diarrea/inducido químicamente , Diarrea/enzimología , Predisposición Genética a la Enfermedad , Heterocigoto , Homocigoto , Humanos , Irinotecán , Neutropenia/inducido químicamente , Neutropenia/enzimología , Oportunidad Relativa , Pruebas de Farmacogenómica , Fenotipo , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Medición de Riesgo , Factores de Riesgo , Resultado del Tratamiento
10.
Phys Rev Lett ; 118(21): 212301, 2017 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-28598664

RESUMEN

We report the first measurement of the elliptic anisotropy (v_{2}) of the charm meson D^{0} at midrapidity (|y|<1) in Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D^{0} v_{2} in 0%-80% centrality Au+Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (p_{T}) of less than 4 GeV/c. The D^{0} v_{2} as a function of transverse kinetic energy (m_{T}-m_{0}, where m_{T}=sqrt[p_{T}^{2}+m_{0}^{2}]) is consistent with that of light mesons in 10%-40% centrality Au+Au collisions. These results suggest that charm quarks have achieved local thermal equilibrium with the medium created in such collisions. Several theoretical models, with the temperature-dependent, dimensionless charm spatial diffusion coefficient (2πTD_{s}) in the range of ∼2-12, are able to simultaneously reproduce our D^{0} v_{2} result and our previously published results for the D^{0} nuclear modification factor.

11.
Phys Rev Lett ; 119(6): 062301, 2017 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-28949601

RESUMEN

We report the first dijet transverse momentum asymmetry measurements from Au+Au and pp collisions at RHIC. The two highest-energy back-to-back jets reconstructed from fragments with transverse momenta above 2 GeV/c display a significantly higher momentum imbalance in heavy-ion collisions than in the pp reference. When reexamined with correlated soft particles included, we observe that these dijets then exhibit a unique new feature-momentum balance is restored to that observed in pp for a jet resolution parameter of R=0.4, while rebalancing is not attained with a smaller value of R=0.2.

12.
Phys Rev Lett ; 118(1): 012301, 2017 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-28106415

RESUMEN

We present the first measurement of charge-dependent directed flow in Cu+Au collisions at sqrt[s_{NN}]=200 GeV. The results are presented as a function of the particle transverse momentum and pseudorapidity for different centralities. A finite difference between the directed flow of positive and negative charged particles is observed that qualitatively agrees with the expectations from the effects of the initial strong electric field between two colliding ions with different nuclear charges. The measured difference in directed flow is much smaller than that obtained from the parton-hadron-string-dynamics model, which suggests that most of the electric charges, i.e., quarks and antiquarks, have not yet been created during the lifetime of the strong electric field, which is of the order of, or less than, 1 fm/c.

13.
J Dairy Sci ; 100(6): 4637-4649, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28342613

RESUMEN

We determined the effects of calf milk replacers containing 0, 5, or 10% bovine plasma protein (PP), either without or with the supplemental amino acids (AA) Ile and Thr, on growth and health of male Holstein calves (n = 104) for 56 d. Milk replacers were formulated to contain 22% crude protein (CP), 20% fat, and 2.0% Lys. Milk replacers (12.5% solids) were fed at a rate of 1.5% of body weight (BW) on a dry matter basis during wk 1 and 1.75% of BW beginning on d 8. Starter was introduced on d 36 so that effects of PP and AA balance in milk replacers could be isolated. Intake, respiratory scores, and fecal scores were measured daily. Body weight and stature were measured weekly and blood serum samples were obtained during wk 4. Treatments had no effects on intakes of dry matter, CP, or metabolizable energy. During wk 6 and 8, BW was less as PP inclusion increased without AA supplementation compared with the other treatments. In wk 7, calves fed the higher level of PP without AA had lower BW than calves fed either the lower level of PP without supplemented AA or the higher inclusion of PP with supplemented AA. Average daily gain and gain:feed were lowest for calves fed the higher inclusion of PP without supplemented AA; heart girth in wk 7 was smallest for those calves. During the first 21 d, occurrence of scours was greater in calves fed the control milk replacer than in calves fed milk replacers containing the higher inclusion of PP either without or with supplemental AA. Occurrence of scours was also greater for the lower inclusion of PP compared with the higher inclusion of PP when AA were supplemented. Throughout the 56-d experiment, the chance of antibiotic treatment was greater for calves fed the control milk replacer than for all other treatments except the higher inclusion of PP without supplemental AA. Additionally, chance of antibiotic treatment was greater for the higher inclusion of PP without supplemental AA than for other milk replacers with PP. Calves fed treatments with the higher inclusion of PP had fewer days of scours than the controls. All milk replacers with PP, except the milk replacer containing higher PP without supplemental AA, had fewer days of treatment with antibiotics compared to the all-milk control. Inclusion of PP provided similar performance and improved health as long as milk replacers were balanced for Ile and Thr.


Asunto(s)
Aminoácidos/administración & dosificación , Proteínas Sanguíneas/administración & dosificación , Estatura/fisiología , Peso Corporal/fisiología , Alimentación Animal , Animales , Antibacterianos/administración & dosificación , Bovinos/crecimiento & desarrollo , Suplementos Dietéticos , Ingestión de Energía , Humanos , Isoleucina , Masculino , Leche , Treonina/administración & dosificación , Aumento de Peso
14.
J Dairy Sci ; 100(1): 293-304, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27865507

RESUMEN

We measured the effects of milk replacers containing 0, 33, 66, or 100% of the total replaceable whey protein as bovine plasma protein (PP), without or with Ile supplementation, on the intake, growth, and health of 124 male Holstein calves for 35d. Milk replacers were formulated to contain 18% crude protein and 20% fat, with contents of Lys and Met equalized. When fed to calves at 1.5% of body weight (dry matter basis) under thermoneutral conditions, diets were predicted to allow average daily gains of 0.55kg/d based on metabolizable energy or 0.40kg/d based on apparent digestible protein. Protein supply was more limiting than energy so that differences in protein use could be detected. Dry matter intakes decreased with increased PP, irrespective of Ile supplementation. Final body weights decreased linearly with increasing PP, regardless of Ile supplementation. Average daily gain tended to be affected in a quadratic manner as PP increased, either with or without Ile supplementation; average daily gain and gain-feed ratio were greatest for calves fed diets containing 33% PP and lowest for calves fed 100% PP. The analyzed Lys content in the milk replacers was variable compared with formulated values, and this may have affected growth results. However, the gain-Lys ratio was affected by an interaction of the linear effect of increasing PP with Ile supplementation: it decreased with increasing PP but was improved by supplementation with Ile for calves fed 100% PP. Body measurements decreased with increasing PP inclusion; only decreased heart girth was reversed with Ile supplementation. The lowest and highest inclusion of PP, regardless of Ile supplementation, decreased the occurrence of scours compared with the control diet (all whey protein). Calves fed the lowest and highest PP without Ile supplementation also had fewer total days of scours in the first 21d. In addition, calves fed 100% PP without supplementation of Ile had fewer days of medication compared with the control diet. Even at the highest PP inclusion, average daily gain was minimally affected if Ile was supplemented. Growth rates, gain-feed ratio, and gain-Lys ratio were decreased at higher PP inclusion, but Ile overcame part of the reduction in gain-Lys ratio for 100% PP. Additional titration studies will have to be conducted to determine optimal PP inclusion rates, with a focus on supplementation of potentially limiting essential AA, as well as effects at higher growth rates.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Leche , Alimentación Animal , Animales , Proteínas Sanguíneas , Bovinos , Dieta/veterinaria , Isoleucina , Aumento de Peso/efectos de los fármacos
15.
Phys Rev Lett ; 116(13): 132301, 2016 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-27081970

RESUMEN

We present the measurement of the transverse single-spin asymmetry of weak boson production in transversely polarized proton-proton collisions at sqrt[s]=500 GeV by the STAR experiment at RHIC. The measured observable is sensitive to the Sivers function, one of the transverse-momentum-dependent parton distribution functions, which is predicted to have the opposite sign in proton-proton collisions from that observed in deep inelastic lepton-proton scattering. These data provide the first experimental investigation of the nonuniversality of the Sivers function, fundamental to our understanding of QCD.

16.
Phys Rev Lett ; 116(6): 062301, 2016 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-26918982

RESUMEN

We present high precision measurements of elliptic flow near midrapidity (|y|<1.0) for multistrange hadrons and ϕ meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy √[sNN]=200 GeV. We observe that the transverse momentum dependence of ϕ and Ω v2 is similar to that of π and p, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0%-30% and 30%-80% collision centrality. There is an indication of the breakdown of previously observed mass ordering between ϕ and proton v2 at low transverse momentum in the 0%-30% centrality range, possibly indicating late hadronic interactions affecting the proton v2.

17.
Phys Rev Lett ; 116(11): 112302, 2016 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-27035295

RESUMEN

We present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au+Au collisions for energies ranging from sqrt[s_{NN}]=7.7 to 200 GeV. The third harmonic v_{3}^{2}{2}=⟨cos3(ϕ_{1}-ϕ_{2})⟩, where ϕ_{1}-ϕ_{2} is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δη=η_{1}-η_{2}. Nonzero v_{3}^{2}{2} is directly related to the previously observed large-Δη narrow-Δϕ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity quark gluon plasma phase. For sufficiently central collisions, v_{3}^{2}{2} persist down to an energy of 7.7 GeV, suggesting that quark gluon plasma may be created even in these low energy collisions. In peripheral collisions at these low energies, however, v_{3}^{2}{2} is consistent with zero. When scaled by the pseudorapidity density of charged-particle multiplicity per participating nucleon pair, v_{3}^{2}{2} for central collisions shows a minimum near sqrt[s_{NN}]=20 GeV.

18.
J Dairy Sci ; 99(11): 9027-9039, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27614833

RESUMEN

Previous studies with calves and other species have provided evidence that blood serum-derived proteins and fructooligosaccharides (FOS) may benefit intestinal health. We assessed the effects of supplementing products containing serum proteins as a component of arrival fluid support or serum proteins plus FOS (in addition to additional solids, minerals, and vitamins) in an early life dietary supplement on performance, morbidity, and mortality of stressed (transport, cold) male calves. Male Holstein calves (n=93) <1 wk old were stratified by arrival body weight (BW) and plasma protein concentration, and then randomly assigned to 1 of 4 treatment groups in a 2×2 factorial arrangement of one-time administration of fluid support [either control electrolyte solution (E) or the serum protein-containing arrival formula (AF)] and 14d of either no supplementation (NG) or supplementation with Gammulin (G; APC Inc., Ankeny, IA), which contains serum proteins and FOS in addition to other solids, minerals, and vitamins. Upon arrival at the research facility, calves were orally administered either AF or E. At the next feeding, half of the calves from each fluid support treatment received either milk replacer (20% crude protein, 20% fat) or the same milk replacer supplemented with G (50g/d during the first 14d). Starter and water were freely available. Feed offered and refused was recorded daily. Calf health was assessed by daily assignment of fecal and respiratory scores. Stature measures and BW were determined weekly. Blood samples were obtained at d 0 (before treatments), 2, 7, 14, and 28. Calves were weaned at d 42 and remained in the experiment until d 56. After 2 wk of treatments, calves previously fed AF had greater body length (66.6 vs. 66.0cm), intakes of dry matter (38.7 vs. 23.5g/d) and crude protein (9.2 vs. 5.6g/d) from starter, and cortisol concentration in blood (17.0 vs. 13.9 ng/mL) than calves fed E. Supplementation with G resulted in greater BW gain during the first 2 wk, increased intakes of dry matter and CP, and decreased respiratory scores. For the 8-wk experiment, G supplementation resulted in lower mean fecal score (1.6 vs. 1.8) and fewer antibiotic treatments per calf (1.5 vs. 2.5) than NG. Survival was greater in G than in NG calves (98 vs. 84%). Despite the marked reduction in morbidity and mortality, blood indicators of acute-phase response, urea N, and total protein were not affected by AF or G in transported cold-stressed male calves.


Asunto(s)
Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Proteínas Sanguíneas/administración & dosificación , Dieta/veterinaria , Alimentos Formulados/análisis , Estrés Fisiológico , Reacción de Fase Aguda/sangre , Animales , Animales Recién Nacidos , Biomarcadores/sangre , Peso Corporal , Bovinos/crecimiento & desarrollo , Heces/química , Inmunoglobulina G/sangre , Masculino , Micronutrientes/administración & dosificación , Micronutrientes/análisis , Nitrógeno/orina , Oligosacáridos/administración & dosificación
19.
Phys Rev Lett ; 114(2): 022301, 2015 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-25635541

RESUMEN

We present ΛΛ correlation measurements in heavy-ion collisions for Au+Au collisions at sqrt[s_{NN}]=200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider. The Lednický-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the ΛΛ correlation function and interaction parameters for dihyperon searches are discussed.

20.
Phys Rev Lett ; 115(22): 222301, 2015 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-26650297

RESUMEN

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v_{2}{2} and v_{2}{4}, for charged hadrons from U+U collisions at sqrt[s_{NN}]=193 GeV and Au+Au collisions at sqrt[s_{NN}]=200 GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v_{2}{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. We also show that v_{2} vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda