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Biomedical subjects

D Keane

Publications and source records attributed to D Keane.

At least 19 recordsLinked to original sources
PubMed2003

A survey of Irish consultants regarding awareness of sperm freezing and assisted reproduction.

Chemotherapy and radiotherapy decrease male fertility. Pretreatment semen cryopreservation offers a chance for future fatherhood. However many eligible patients are not referred. One potential reason for the reduced uptake is lack of awareness by referring consultants. We sent a questionnaire to all 41 consultant oncologists, haematologists and urologists listed in the Irish Medical Directory. The questionnaire surveyed the current knowledge, opinions and clinical practices of this key group regarding semen cryopreservation for male cancer patients. 63% responded. 73% routinely discuss semen freezing with their male cancer patients (mostly testicular carcinomas and lymphomas). 100% believe semen cryopreservation helps the patient psychologically. 12% do not know where facilities exist. 92% will only refer men aged between 20 and 40 years. 92% are unaware that semen freezing does not delay cancer treatment. 54% have heard of intracytoplasmic sperm injection (ICSI) but 88% are unaware of its benefits for patients with low sperm counts. Consultants dealing with male cancer patients do not prioritise future fertility. Most of the consultants surveyed were unaware of the advances in reproductive technology and this may be contributing to underutilization of sperm cryopreservation by male cancer patients. Units offering this service need to increase awareness of its potential benefits.

Awareness↗
PubMed2002

Coherent rho(0) production in ultraperipheral heavy-ion collisions.

The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au*Au*rho(0), in ultraperipheral heavy-ion collisions. The rho(0) have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[s(NN)]=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.

Journal Article↗
PubMed2002

Azimuthal anisotropy of K(0)(S) and Lambda+Lambda production at midrapidity from Au+Au collisions at sqrt[s(NN)]=130 GeV.

We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrt[s(NN)]=130 GeV at the Relativistic Heavy Ion Collider. The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 3.0 GeV/c. A strong p(t) dependence in v(2) is observed up to 2.0 GeV/c. The v(2) measurement is compared with hydrodynamic model calculations. The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed.

Journal Article↗
PubMed2002

Longitudinal flow of protons from (2-8)A GeV central Au+Au collisions.

Rapidity distributions of protons from central 197Au+197Au collisions measured by the E895 Collaboration in the energy range from (2-8)A GeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion are extracted from these distributions. The results show an approximately linear increase in the longitudinal flow velocity, (L), as a function of the logarithm of beam energy.

Journal Article↗
PubMed2001

d Macro and (3)He macro production in square root of s(NN) = 130 GeV Au+Au collisions.

The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. The observed production rates for d macro and (3)He macro are much larger than in lower energy nucleus-nucleus collisions. A coalescence model analysis of the yields indicates that there is little or no increase in the antinucleon freeze-out volume compared to collisions at CERN SPS energy. These analyses also indicate that the (3)He macro freeze-out volume is smaller than the d macro freeze-out volume.

Journal Article↗
PubMed2001

Measurement of inclusive antiprotons from Au+Au collisions at square root of s(NN) = 130 GeV.

We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at square root of s(NN) = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. The extrapolated antiproton rapidity density is found to scale approximately with the negative hadron multiplicity density.

Journal Article↗
PubMed2001

Model-independent source imaging using two-pion correlations in (2 to 8)a GeV Au+Au collisions.

We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au+Au collisions at beam energies between 2A and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The extracted source functions have Gaussian shapes. Values of source functions at zero separation are almost constant across the energy range under study. Imaging results are found to be consistent with conventional source parameters obtained from a multidimensional Hanburg-Brown-Twiss analysis.

Journal Article↗
PubMed2001

Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at square root of (sNN) = 130 GeV.

The minimum-bias multiplicity distribution and the transverse momentum and pseudorapidity distributions for central collisions have been measured for negative hadrons ( h(-)) in Au+Au interactions at square root of ([s(NN)]) = 130 GeV. The multiplicity density at midrapidity for the 5% most central interactions is dN(h(-))/d(eta)/(eta = 0) = 280+/-1(stat)+/-20(syst), an increase per participant of 38% relative to pp collisions at the same energy. The mean transverse momentum is 0.508+/-0.012 GeV/c and is larger than in central Pb+Pb collisions at lower energies. The scaling of the h(-) yield per participant is a strong function of p( perpendicular). The pseudorapidity distribution is almost constant within /eta/<1.

Journal Article↗
PubMed2001

Midrapidity antiproton-to-proton ratio from Au+Au collisions at sqrt [s(NN)]=130 GeV.

We report results on the ratio of midrapidity antiproton-to-proton yields in Au+Au collisions at sqrt[s(NN)] = 130 GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of /y/<0.5 and 0.4<p(t)<1.0 GeV/c, the ratio is essentially independent of either transverse momentum or rapidity, with an average of 0.65+/-0.01((stat))+/-0.07((syst)) for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the p-p pair production becomes important at midrapidity, a significant excess of baryons over antibaryons is still present.

Journal Article↗
PubMed2001

Directed flow of lambda hyperons in (2-6 )A GeV Au+Au collisions.

Directed flow measurements for Lambda hyperons are presented and compared to those for protons produced in the same Au+Au collisions (2A, 4A, and 6A GeV; b<5-6 fm). The measurements indicate that Lambda hyperons flow consistently in the same direction but with smaller magnitudes. A strong positive flow [for Lambdas] has been predicted in calculations which include the influence of the Lambda-nucleon potential. The experimental flow ratio Lambda/p is in qualitative agreement with expectations (approximately 2/3) from the quark counting rule at 2A GeV but is found to decrease with increasing beam energy.

Journal Article↗
PubMed2001

Peripartum hysterectomy in the 1990s: any new lessons?

We aimed to identify the risk factors and subsequent maternal and perinatal outcome associated with the procedure of peripartum hysterectomy. This was a retrospective case review carried out at the National Maternity Hospital, Dublin, of all patients who underwent a peripartum hysterectomy from January 1990 to December 1999. Seventeen cases were performed during the study period from a total of 64 563 deliveries (0.03%). Mean maternal age was 34 years (21-43). There were no nulliparous patients. Eight patients had previous vaginal deliveries. The other nine had a history of previous caesarean section, four of whom had two or more caesarean sections. The indications for the hysterectomy were placenta praevia (5), secondary postpartum haemorrhage (3), abruptio placentae (3), atonic postpartum haemorrhage (2), placenta accreta (2), traumatic postpartum haemorrhage (1) and broad ligament haematoma (1). All patients received blood transfusions, 74% receiving more than 10 units. There were no maternal deaths. There were two neonatal deaths secondary to placental abruption (perinatal mortality rate 118/1000). In conclusion, there was no maternal death in this study but the associated maternal morbidity and perinatal mortality was high. More than half the cases were associated with previous caesarean section. The caesarean section rate is increasing worldwide for many reasons, including recent emphasis on maternal request. We recommend that caesarean section be performed only for valid clinical indications, which should help to reduce the problems associated with peripartum hysterectomy.

Journal Article↗
PubMed2000

Does HIV reporting by name deter testing? MESH Study Group.

OBJECTIVE: Name-based HIV reporting is controversial in the United States because of concerns that it may deter high-risk persons from being tested. We sought to determine whether persons at risk of HIV infection knew their state's HIV reporting policy and whether they had delayed or avoided testing because of it. DESIGN: A cross-sectional anonymous survey. METHODS: We interviewed 2404 participants in one of three high-risk groups: men who have sex with men (MSM), heterosexuals attending a sexually transmitted disease (STD) clinic, and street-recruited injection drug users (IDU). Participants were asked standardized questions about their knowledge of reporting policies and reasons for having delayed or avoided testing. We recruited in eight US states: four with name-based reporting and four without; all offered anonymous testing at certain sites. RESULTS: Fewer than 25% correctly identified their state's HIV reporting policy. Over 50% stated they did not know whether their state used name-based reporting. Of the total, 480 participants (20%) had never been tested. Of these, 17% from states with name-based reporting selected concern about reporting as a reason for not testing compared with 14% from states without name-based reporting (P = 0.5). Comparing previously tested participants from states with name-based reporting to those from states without, concern about HIV reporting was given as a reason for delaying testing by 26% compared with 13% of IDU (P < 0.001), and for 26% compared with 19% of MSM (P = 0.06). CONCLUSION: Most participants did not know their state's HIV reporting policy. Name-based reporting policies were not associated with avoiding HIV testing because of worry about reporting, although they may have contributed to delays in testing among some IDU.

AIDS Serodiagnosis↗
PubMed2000

Nuclear multifragmentation, percolation, and the fisher droplet model: common features of reducibility and thermal scaling

It is shown that the Fisher droplet model, percolation, and nuclear multifragmentation share the common features of reducibility (stochasticity in multiplicity distributions) and thermal scaling (one-fragment production probabilities are Boltzmann factors). Barriers obtained, for cluster production on percolation lattices, from the Boltzmann factors show a power-law dependence on cluster size with an exponent of 0.42+/-0.02. The EOS Collaboration Au multifragmentation data yield barriers with a power-law exponent of 0.68+/-0.03. Values of the surface energy coefficient of a low density nuclear system are also extracted.

Journal Article↗
PubMed2000

Antiflow of K(0)(s) mesons in 6A GeV Au + Au collisions

We have measured the sideward flow of neutral strange ( K(0)(s)) mesons in 6A GeV Au+Au collisions. A prominent antiflow signal is observed for an impact parameter range ( b less, similar7 fm) which spans central and midcentral events. Since the K(0)(s) scattering cross section is relatively small in nuclear matter, this observation suggests that the in-medium kaon vector potential plays an important role in high density nuclear matter.

Journal Article↗
PubMed2000

Sideward flow in Au+Au collisions between 2A and 8A GeV

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Journal Article↗
PubMed2000

Bombarding energy dependence of pi(-) interferometry at the brookhaven AGS

We present the first excitation function of pi(-) intensity interferometry at Alternating Gradient Synchrotron (AGS) energies (2-8 A GeV). The sensitivity of the multidimensional correlation functions to the geometry and dynamics of the pion-emitting system provides a stringent test of transport models of heavy ion collisions. Detailed comparisons with a realistic transport model, both with and without an explicit nuclear mean field, suggest that the beam energy evolution in the reaction dynamics is different in the model than in the data. A significantly increased pi(-) emission time scale, which has been suggested as a signal of the onset of the transition to quark-gluon plasma, is not observed.

Journal Article↗