2,318 research outputs found
Irradiation of a nanocomposite of pseudoboehmite-nylon 6,12
Nanocomposites are nanometrical material particles embedded in a specific matrix. The degree of organization of the nanostructures and their properties depend on the nature of the organic and inorganic components of the structure that can generate synergic interactions. Polymeric nanocomposites are related to a class of hybrid materials where inorganic substances of nanometric dimensions are dispersed in a polymeric matrix. In the present work, nanocomposites of nylon 6,12 with different concentrations of pseudoboehmite obtained by sol-gel process were prepared with and without the presence of octadecylamine. After preparation, the samples were irradiated with a 200 kGy radiation dose in an electron accelerator. The pseudoboehmite nano particles were characterized by X-ray diffraction, scanning electron microscopy, differential thermal analysis and thermo gravimetric analysis. The nanocomposites were characterized by thermal and mechanical tests. The addition of pseudoboehmite promoted a reduction of the melting flow during the production of the composites evidencing the interaction of pseudoboehmite with the polymeric matrix, probably modifying its crystalline structure
Prevalence, treatment, and control of dyslipidemia in diabetic participants of two Brazilian cohorts: a place far from heaven
Diabetes is one of the leading causes of cardiovascular mortality. Over the last years, mortality has decreased significantly, more in individuals with diabetes than in healthy ones. That is mostly due to the control of other cardiovascular risk factors. The objective of our study was to analyze the dyslipidemia control in two diabetes cohorts. Patients from two distinct cohorts were studied, 173 patients from the BHS (Brasilia Heart Study) and 222 patients from the BDS (Brazilian Diabetes Study). The data on dyslipidemia control were studied in both different populations. All patients had diabetes. There are significant differences concerning comorbidities between the LDL-C and BDS groups. The average glycated hemoglobin is of 8.2 in the LDL-C > 100 group in comparison with 7.7 and 7.5 in the 70-100 and 100 groups (54.3% and 54.9%, respectively; p = 0.005). Diastolic pressure is higher in the group with LDL > 100, with an average of 87 mmHg, in comparison with 82.6 mmHg and 81.9 mmHg in the 70-100 and 100 has the greatest percentage of smokers (8.7%) in comparison with the groups with LDL between 70-100 and 100 groups, respectively (p < 0.001). The data in our study have shown that the dyslipidemia control in diabetic patients is inadequate and there is a tendency of direct association between lack of blood glucose control and lack of dyslipidemia control, in addition to the association with other cardiovascular risk factors, such as diastolic hypertension and smoking. This worsened control might be related to the plateau in the descending curve of mortality, and investments in this regard can improve the cardiovascular health in diabetic patients.6513
Mass dependence of light nucleus production in ultrarelativistic heavy ion collisions
Light nuclei can be produced in the central reaction zone via coalescence in
relativistic heavy ion collisions. E864 at BNL has measured the production of
ten light nuclei with nuclear number of A=1 to A=7 at rapidity and
. Data were taken with a Au beam of momentum of 11.5 A
on a Pb or Pt target with different experimental settings. The
invariant yields show a striking exponential dependence on nuclear number with
a penalty factor of about 50 per additional nucleon. Detailed analysis reveals
that the production may depend on the spin factor of the nucleus and the
nuclear binding energy as well.Comment: (6 pages, 3 figures), some changes on text, references and figures'
lettering. To be published in PRL (13Dec1999
Measurements of Light Nuclei Production in 11.5 A GeV/c Au+Pb Heavy-Ion Collisions
We report on measurements by the E864 experiment at the BNL-AGS of the yields
of light nuclei in collisions of Au(197) with beam momentum of 11.5 A GeV/c on
targets of Pb(208) and Pt(197). The yields are reported for nuclei with baryon
number A=1 up to A=7, and typically cover a rapidity range from y(cm) to
y(cm)+1 and a transverse momentum range of approximately 0.1 < p(T)/A < 0.5
GeV/c. We calculate coalescence scale factors B(A) from which we extract model
dependent source dimensions and collective flow velocities. We also examine the
dependences of the yields on baryon number, spin, and isospin of the produced
nuclei.Comment: 21 figures-to be published in Phys. Rev.
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at = 2.76 TeV
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/388
Antiproton Production in 11.5 A GeV/c Au+Pb Nucleus-Nucleus Collisions
We present the first results from the E864 collaboration on the production of
antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the
Brookhaven AGS. We report invariant multiplicities for antiproton production in
the kinematic region 1.4<y<2.2 and 50<p_T<300 MeV/c, and compare our data with
a first collision scaling model and previously published results from the E878
collaboration. The differences between the E864 and E878 antiproton
measurements and the implications for antihyperon production are discussed.Comment: 4 pages, 4 figures; accepted for publication in Physical Review
Letter
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at TeV
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb
collisions at = 2.76 TeV have been measured by the ALICE
Collaboration at the LHC. The data are presented for central and peripheral
collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross
section. The measured charged particle spectra in and GeV/ are compared to the expectation in pp collisions at the same
, scaled by the number of underlying nucleon-nucleon
collisions. The comparison is expressed in terms of the nuclear modification
factor . The result indicates only weak medium effects ( 0.7) in peripheral collisions. In central collisions,
reaches a minimum of about 0.14 at -7GeV/ and increases
significantly at larger . The measured suppression of high- particles is stronger than that observed at lower collision energies,
indicating that a very dense medium is formed in central Pb-Pb collisions at
the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98
An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement
The QCD phase diagram lies at the heart of what the RHIC Physics Program is
all about. While RHIC has been operating very successfully at or close to its
maximum energy for almost a decade, it has become clear that this collider can
also be operated at lower energies down to 5 GeV without extensive upgrades. An
exploration of the full region of beam energies available at the RHIC facility
is imperative. The STAR detector, due to its large uniform acceptance and
excellent particle identification capabilities, is uniquely positioned to carry
out this program in depth and detail. The first exploratory beam energy scan
(BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades,
most importantly a full barrel Time of Flight detector, are now completed which
add new capabilities important for the interesting physics at BES energies. In
this document we discuss current proposed measurements, with estimations of the
accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure
Pion interferometry in Au+Au collisions at = 200 GeV
We present a systematic analysis of two-pion interferometry in Au+Au
collisions at = 200 GeV using the STAR detector at RHIC. We
extract the HBT radii and study their multiplicity, transverse momentum, and
azimuthal angle dependence. The Gaussianess of the correlation function is
studied. Estimates of the geometrical and dynamical structure of the freeze-out
source are extracted by fits with blast wave parameterizations. The expansion
of the source and its relation with the initial energy density distribution is
studied.Comment: 21 pages, 30 figures. As published in Physics Review
Qualitative analysis of the viability of autogenous fat grafts grafted in different environments of interstitial pressure. Preliminary results and description of a new experimental model in mini-pigs
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