ABSTRACT
The water maze is a complex spatial task that requires the coordination of multiple systems to perform efficiently. Various factors have been shown to influence performance in this task, including motivational state and prior experience. Although a consistent sex difference has been observed in acquiring the water maze in rats, the contribution of the various factors in female rat performance has not been fully assessed. Therefore, the current study tested the effects of motivation as manipulated by water temperature of the maze and prior experience in the maze on the performance of female rats. It was hypothesized that females pretrained in the maze would perform better than those without exposure to the water maze, regardless of water temperature, but in naïve rats, colder water would improve performance as shown previously in male rats. For pretraining, female rats were taught to find a visible platform in cold (19 °C, 4 trials on one day) and warm (25 °C, 4 trials on one day) water before acquisition trials, with the order of the water temperature randomly assigned. Control rats were not given any training and were naïve to the water maze procedure. Pretrained and control rats were then tested to locate a hidden platform in either cold or warm water for 5 consecutive days. Overall, pretraining had a significant effect on distance, latency, and directness of path to the platform. Water temperature did not show a significant effect on any measure or a significant interaction with pretraining. Thus, while our hypothesis that pretraining would improve performance was supported, the results did not support the prediction that water temperature would also significantly influence performance. These results show that non-spatial pretraining can critically improve the performance of females in acquiring a place strategy for the hidden platform, irrespective of water temperature.
Subject(s)
Maze Learning/physiology , Motor Activity/physiology , Practice, Psychological , Spatial Behavior/physiology , Temperature , Animals , Behavior, Animal/physiology , Female , Memory/physiology , Rats , Rats, Sprague-Dawley , Space Perception/physiology , WaterABSTRACT
We present a new measurement of the difference between the nucleon strange and antistrange quark distributions from dimuon events recorded by the NuTeV experiment at Fermilab. This analysis is the first to use a complete next to leading order QCD description of charm production from neutrino scattering. Dimuon events in neutrino deep inelastic scattering allow direct and independent study of the strange and antistrange content of the nucleon. We find a positive strange asymmetry with a significance of 1.6sigma. We also report a new measurement of the charm mass.
ABSTRACT
Limits on nu(mu)-->nu(e) and nu(mu)-->nu(e) oscillations are extracted using the NuTeV detector with sign-selected nu(mu) and nu(mu) beams. In nu(mu) mode, for the case of sin(2)2alpha = 1, Delta(m)(2)>2.6 eV(2) is excluded, and for Delta(m)(2)>>1000 eV(2), sin(2)2alpha>1.1 x 10(-3). The NuTeV data exclude the high Delta(m)(2) end of nu(mu)-->nu(e) oscillation parameters favored by the LSND experiment without the need to assume that the oscillation parameters for nu and nu are the same. We present the most stringent experimental limits for nu(mu)(nu(mu))-->nu(e)(nu(e)) oscillations in the large Delta(m)(2) region.
ABSTRACT
The NuTeV Collaboration has extracted the electroweak parameter sin(2)theta(W) from the measurement of the ratios of neutral current to charged current nu and (-)nu cross sections. Our value, sin(2)theta((on-shell))(W) = 0.2277 +/- 0.0013(stat) +/- 0.0009(syst), is 3 standard deviations above the standard model prediction. We also present a model independent analysis of the same data in terms of neutral-current quark couplings.
ABSTRACT
We report on the extraction of R = sigma(L)/sigma(T) from CCFR nu(mu)-Fe and nu(mu)-Fe differential cross sections. The CCFR differential cross sections do not show the deviations from the QCD expectations that are seen in the CDHSW data at very low and very high x. R as measured in nu(mu) scattering is in agreement with R as measured in muon and electron scattering. All data on R for Q(2)>1 GeV(2) are in agreement with a NNLO QCD calculation which uses NNLO parton distribution functions and includes target mass effects. We report on the first measurements of R in the low x and Q(2)<1 GeV(2) region (where an anomalous large rise in R for nuclear targets has been observed by the HERMES Collaboration).
ABSTRACT
The NuTeV experiment at Fermilab has used a sign-selected neutrino beam to perform a search for the lepton number violating process nu(mu)e(-)-->mu(-)nu(e), and to measure the cross section of the standard model inverse muon decay process nu(mu)e(-)-->mu(-)nu(e). NuTeV measures the inverse muon decay asymptotic cross-section slope sigma/E to be (13.8 +/- 1.2 +/- 1.4) x 10(-42) cm(2)/GeV. The experiment also observes no evidence for lepton number violation and places one of the most restrictive limits on the cross-section ratio sigma(nu(mu)e(-)-->mu(-)nu(e))/sigma(nu(mu)e(-)-->mu(-)nu(e)) < or = 1.7% at 90% C.L. for V-A couplings and < or = 0.6% for scalar couplings.
ABSTRACT
A search for long-lived neutral particles ( N0's) with masses above 2.2 GeV/c(2) that decay into at least one muon has been performed using an instrumented decay channel at the NuTeV experiment at Fermilab. Data were examined for particles decaying into the final states mumu, mu(e), and mu(pi). Three mumu events were observed over an expected standard model background of 0.069+/-0.010 events; no events were observed in the other modes.
ABSTRACT
A new structure function analysis of CCFR deep inelastic nu-N and nu-N scattering data is presented for previously unexplored kinematic regions down to Bjorken x = 0.0045 and Q(2) = 0.3 GeV(2). Comparisons to charged lepton scattering data from NMC and E665 experiments are made and the behavior of the structure function F(2)(nu)2 is studied in the limit Q(2)-->0.
ABSTRACT
We report on the extraction of the structure functions F2 and DeltaxF(3) = xF(nu)(3)-xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe differential cross sections. The extraction is performed in a physics model-independent (PMI) way. This first measurement of DeltaxF(3), which is useful in testing models of heavy charm production, is higher than current theoretical predictions. The ratio of the F2 (PMI) values measured in nu(mu) and mu scattering is in agreement (within 5%) with the predictions of next-to-leading-order parton distribution functions using massive charm production schemes, thus resolving the long-standing discrepancy between the two sets of data.
ABSTRACT
The E815 (NuTeV) neutrino experiment has performed a search for a 33. 9 MeV/c(2) weakly interacting neutral particle produced in pion decay. Such a particle may be responsible for an anomaly in the timing distribution of neutrino interactions in the KARMEN experiment. E815 has searched for this particle's decays in an instrumented decay region; no evidence for this particle was found. The search is sensitive to pion branching ratios as low as 10(-13).
ABSTRACT
Even when there is not direct relation between psoriasis and AIDS, there have been reported impressive manifestations of psoriasis in AIDS diagnosis, difficulties in response to therapy, increase of serious forms of the disease, and clearing of lesions in terminal phase of AIDS. Two cases in which the two diseases are associated were presented. Both cases had outbreaking psoriasis guttata, one of them after being diagnosed with AIDS, in addition to have other dermatosis such as leukoplasia and ungual candidiasis; and the two patients also had scabies. Additionally, presentation of generalized lesions resistant to prescribed therapies was observed.
Subject(s)
Adult , Humans , Male , HIV-1 , Psoriasis/diagnosis , Acquired Immunodeficiency Syndrome/diagnosis , Psoriasis/etiology , Acquired Immunodeficiency Syndrome/complicationsABSTRACT
Aunque no existe una relación directa psoriasis-SIDA se ha notificado :manifestación impresionante de la psoriasis en el diagnóstico de SIDA, dificultad en la respuesta terapéutica, aumento de las formas graves de la enfermedad y aclaramiento de las lesiones en la fase terminal del SIDA. Se mostraron 2 casos donde se asocian las dos enfermedades. Ambos casos presentaron psoriasis guttata en brote, uno de ellos comenzó posterior al diagnóstico del virus de inmunodeficiencia humana, que además presentó otras dermatosis como: leucoplasia, candidiasis ungueal y los 2 casos presentaron escabiosis. Se observó, además, una tendencia a la presentación de lesiones generalizadas y resistentes a las terapéuticas indicadas(AU)
Subject(s)
Humans , Psoriasis , Acquired Immunodeficiency SyndromeABSTRACT
After reviewing the literature on this topic, the paper examines fetal effects during maternal anti-hypertensive treatment, assessing both possible teratogenic results and fetal outcome. All anti-hypertensive agents cross the placental barrier and are present in varying concentrations in the fetal circulation, thus provoking varying effects on the cardiocirculatory apparatus and fetal metabolism. Some agents, such as alpha-metildopa, may be considered reliable, whereas others, like ACE-inhibitors, are still used with considerable caution, an attitude which will only change following extensive clinical trials and through post-natal checks.
Subject(s)
Antihypertensive Agents/adverse effects , Fetus/drug effects , Antihypertensive Agents/pharmacokinetics , Female , Fetal Growth Retardation/chemically induced , Humans , Infant, Newborn , Pregnancy , Pregnancy Outcome , Prenatal Exposure Delayed Effects , Teratogens/pharmacologyABSTRACT
The effect of the pretreatment of human peripheral blood lymphocytes by Prostaglandin E2 (dissolved in medium) on the spontaneous Plaque-Forming Cell generation has been evaluated. A significant enhancement of immunoglobulin production, markedly increased by the addition of further PGE2 to the pretreated cells, has been demonstrated. Experiments carried out with indomethacin have shown an inhibition of plaque formation, thus indicating that the content of endogenous prostaglandin E2 may play an important role in the enhancement of antibody synthesis, previously described. Results obtained with populations of rosetting and non-rosetting lymphocytes pointed out that non-rosetting cells are exclusively responsive to prostaglandin treatment.
