55 research outputs found
Production of phi mesons at mid-rapidity in sqrt(s_NN) = 200 GeV Au+Au collisions at RHIC
We present the first results of meson production in the K^+K^- decay channel
from Au+Au collisions at sqrt(s_NN) = 200 GeV as measured at mid-rapidity by
the PHENIX detector at RHIC. Precision resonance centroid and width values are
extracted as a function of collision centrality. No significant variation from
the PDG accepted values is observed. The transverse mass spectra are fitted
with a linear exponential function for which the derived inverse slope
parameter is seen to be constant as a function of centrality. These data are
also fitted by a hydrodynamic model with the result that the freeze-out
temperature and the expansion velocity values are consistent with the values
previously derived from fitting single hadron inclusive data. As a function of
transverse momentum the collisions scaled peripheral.to.central yield ratio RCP
for the is comparable to that of pions rather than that of protons. This result
lends support to theoretical models which distinguish between baryons and
mesons instead of particle mass for explaining the anomalous proton yield.Comment: 326 authors, 24 pages text, 23 figures, 6 tables, RevTeX 4. To be
submitted to Physical Review C as a regular article. Plain text data tables
for the points plotted in figures for this and previous PHENIX publications
are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
Prolactin receptor antagonism reduces the clonogenic capacity of breast cancer cells and potentiates doxorubicin and paclitaxel cytotoxicity
Motor-Coordination-Dependent Learning, More than Others, Is Impaired in Transgenic Mice Expressing Pseudorabies Virus Immediate-Early Protein IE180
The cerebellum in transgenic mice expressing pseudorabies virus immediate-early protein IE180 (TgIE96) was substantially diminished in size, and its histoarchitecture was severely disorganized, resulting in severe ataxia. TgIE96 mice can therefore be used as an experimental model to study the involvement of cerebellar circuits in different learning tasks. The performance of three-month-old TgIE96 mice was studied in various behavioral tests, including associative learning (classical eyeblink conditioning), object recognition, spatial orientation (water maze), startle response and prepulse inhibition, and passive avoidance, and compared with that of wild-type mice. Wild-type and TgIE96 mice presented similar reflexively evoked eyeblinks, and acquired classical conditioned eyelid responses with similar learning curves for both trace and delay conditioning paradigms. The two groups of mice also had similar performances during the object recognition test. However, they showed significant differences for the other three tests included in this study. Although both groups of animals were capable of swimming, TgIE96 mice failed to learn the water maze task during the allowed time. The startle response to a severe tone was similar in both control and TgIE96 mice, but the latter were unable to produce a significant prepulse inhibition. TgIE96 mice also presented evident deficits for the proper accomplishment of a passive avoidance test. These results suggest that the cerebellum is not indispensable for the performance of classical eyeblink conditioning and for object recognition tasks, but seems to be necessary for the proper performance of water maze, prepulse inhibition, and passive avoidance tests
Supplementation of Male Pheromone on Rock Substrates Attracts Female Rock Lizards to the Territories of Males: A Field Experiment
Background: Many animals produce elaborated sexual signals to attract mates, among them are common chemical sexual signals (pheromones) with an attracting function. Lizards produce chemical secretions for scent marking that may have a role in sexual selection. In the laboratory, female rock lizards (Iberolacerta cyreni) prefer the scent of males with more ergosterol in their femoral secretions. However, it is not known whether the scent-marks of male rock lizards may actually attract females to male territories in the field. Methodology/Principal Findings: In the field, we added ergosterol to rocks inside the territories of male lizards, and found that this manipulation resulted in increased relative densities of females in these territories. Furthermore, a higher number of females were observed associated to males in manipulated plots, which probably increased mating opportunities for males in these areas. Conclusions/Significance: These and previous laboratory results suggest that female rock lizards may select to settle in home ranges based on the characteristics of scent-marks from conspecific males. Therefore, male rock lizards might attract more females and obtain more matings by increasing the proportion of ergosterol when scent-marking their territories. However, previous studies suggest that the allocation of ergosterol to secretions may be costly and only high quality male
Autism and ADHD Symptoms in Patients with OCD: Are They Associated with Specific OC Symptom Dimensions or OC Symptom Severity?
In obsessive-compulsive disorder (OCD), the relationship between autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder (ADHD) symptom, and obsessive-compulsive (OC) symptom dimensions and severity has scarcely been studied. Therefore, 109 adult outpatients with primary OCD were compared to 87 healthy controls on OC, ADHD and ASD symptoms. OCD patients showed increased ADHD and autism symptom frequencies, OCD + ADHD patients reporting more autism symptoms (particularly attention switching and social skills problems) than OCD − ADHD patients. Attention switching problems were most significant predictors of OC symptom dimensions (except hoarding) and of symptom severity. Hoarding was not associated with elevated autism scale scores, but with inattention. In conclusion, attention switching problems may reflect both symptom overlap and a common etiological factor underlying ASD, ADHD and OCD
The interpretations and uses of fitness landscapes in the social sciences
__Abstract__
This working paper precedes our full article entitled “The evolution of Wright’s (1932) adaptive field to contemporary interpretations and uses of fitness landscapes in the social sciences” as published in the journal Biology & Philosophy (http://link.springer.com/article/10.1007/s10539-014-9450-2). The working paper features an extended literature overview of the ways in which fitness landscapes have been interpreted and used in the social sciences, for which there was not enough space in the full article. The article features an in-depth philosophical discussion about the added value of the various ways in which fitness landscapes are used in the social sciences. This discussion is absent in the current working paper. Th
J/psi production from proton-proton collisions at sqrt(s) = 200 GeV
J/psi production has been measured in proton-proton collisions at sqrt(s)=
200 GeV over a wide rapidity and transverse momentum range by the PHENIX
experiment at RHIC. Distributions of the rapidity and transverse momentum,
along with measurements of the mean transverse momentum and total production
cross section are presented and compared to available theoretical calculations.
The total J/psi cross section is 3.99 +/- 0.61(stat) +/- 0.58(sys) +/-
0.40(abs) micro barns. The mean transverse momentum is 1.80 +/- 0.23(stat) +/-
0.16(sys) GeV/c.Comment: 326 authors, 6 pages text, 4 figures, 1 table, RevTeX 4. To be
submitted to PRL. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
Measurement of Single Electron Event Anisotropy in Au+Au Collisions at sqrt(s_NN) = 200 GeV
The transverse momentum dependence of the azimuthal anisotropy parameter v_2,
the second harmonic of the azimuthal distribution, for electrons at
mid-rapidity (|eta| < 0.35) has been measured with the PHENIX detector in Au+Au
collisions at sqrt(s_NN) = 200 GeV. The measurement was made with respect to
the reaction plane defined at high rapidities (|eta| = 3.1 -- 3.9). From the
result we have measured the v_2 of electrons from heavy flavor decay after
subtraction of the v_2 of electrons from other sources such as photon
conversions and Dalitz decay from light neutral mesons. We observe a non-zero
single electron v_2 with a 90% confidence level in the intermediate p_T region.Comment: 330 authors, 11 pages text, RevTeX4, 9 figures, 1 tables. Submitted
to Physical Review C. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (or will be) publicly
available at http://www.phenix.bnl.gov/papers.htm
Systematic Studies of the Centrality and sqrt(s_NN) Dependence of dE_T/deta and dN_ch/deta in Heavy Ion Collisions at Mid-rapidity
The PHENIX experiment at RHIC has measured transverse energy and charged
particle multiplicity at mid-rapidity in Au+Au collisions at sqrt(s_NN) = 19.6,
130 and 200 GeV as a function of centrality. The presented results are compared
to measurements from other RHIC experiments, and experiments at lower energies.
The sqrt(s_NN) dependence of dE_T/deta and dN_ch/deta per pair of participants
is consistent with logarithmic scaling for the most central events. The
centrality dependence of dE_T/deta and dN_ch/deta is similar at all measured
incident energies. At RHIC energies the ratio of transverse energy per charged
particle was found independent of centrality and growing slowly with
sqrt(s_NN). A survey of comparisons between the data and available theoretical
models is also presented.Comment: 327 authors, 25 pages text, 19 figures, 17 tables, RevTeX 4. To be
submitted to Physical Review C as a regular article. Plain text data tables
for the points plotted in figures for this and previous PHENIX publications
are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
Centrality Dependence of Charm Production from Single Electrons in Au+Au Collisions at sqrt(s_NN) = 200 GeV
The PHENIX experiment has measured mid-rapidity transverse momentum spectra
(0.4 < p_T < 4.0 GeV/c) of single electrons as a function of centrality in
Au+Au collisions at sqrt(s_NN) = 200 GeV. Contributions to the raw spectra from
photon conversions and Dalitz decays of light neutral mesons are measured by
introducing a thin (1.7% X_0) converter into the PHENIX acceptance and are
statistically removed. The subtracted ``non-photonic'' electron spectra are
primarily due to the semi-leptonic decays of hadrons containing heavy quarks
(charm and bottom). For all centralities, charm production is found to scale
with the nuclear overlap function, T_AA. For minimum-bias collisions the charm
cross section per binary collision is N_cc^bar/T_AA = 622 +/- 57 (stat.) +/-
160 (sys.) microbarns.Comment: 326 authors, 4 pages text, 3 figures, 1 table, RevTeX 4. To be
submitted to Physical Review Letters. Plain text data tables for the points
plotted in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
- …