231 research outputs found
Getting to Know US Latinos: A Step Toward Cultural Competence
Data from the 2010 US Census Bureau, Latinos are one of the largest non-White groups in the United States, a trend expected to continue during the next two decades. Despite their status as the largest nonWhite populations in the US, Latinos continue to be poorly understood and their heterogeneous backgrounds are often ignored. The purpose of this paper is to describe an interactive learning activity designed to explore Latino demographics, food preferences, and culturally-specific health practices and beliefs among this population that traces its roots to many Latin American countries extending from Mexico to Tierra del Fuego and some Caribbean islands. The activity described in this paper is designed for English speaking audiences and may be used with junior or senior high school or college student
Upper critical field from normal state fluctuations in BiSrCuO
The in-plane magnetoresistance of an epitaxial BiSrCuO
thin film was systematically investigated as a function of doping, above .
The orbital magnetoconductance is used to extract the crossover field line
in the fluctuation regime. This field is found in good agreement
with the upper critical field obtained from resistivity data below , and
exhibits a similar upward curvature, thus pointing toward the existence of a
critical correlation length. The consequences regarding the nature of the
resistive transition are discussed
Research Performance of the ASEAN University Network Member Universities
The purpose of this research paper is to describe the research outputs of the member universities of the ASEAN University Network (AUN). The paper is an inductive type of research that used a variety of information from Scopus to determine what AUN member universities are actively writing about. The author captured data from 1997 to 2017 from scopus.com to analyze what the AUN member universities and their respective countries have been studying. Results show that almost 50% of the total research outputs of all the ASEAN nations are contributed by the AUN member Universities, with Singapore’s NUS and NUT contributing 76% of Singapore’s total research outputs, while the Philippines’ DLSU, ADMU, and UP contributes 50%. Wealthy nations such as Singapore and Malaysia have been focusing their researches on engineering and computer sciences while countries like the Philippines, Laos, and Cambodia have been researching about agriculture and biological sciences. Another study can be conducted to show research activities of the different universities all over Asia, including those that are not part of the ASEAN University Network
Destroying coherence in high temperature superconductors with current flow
The loss of single-particle coherence going from the superconducting state to
the normal state in underdoped cuprates is a dramatic effect that has yet to be
understood. Here, we address this issue by performing angle resolved
photoemission spectroscopy (ARPES) measurements in the presence of a transport
current. We find that the loss of coherence is associated with the development
of an onset in the resistance, in that well before the midpoint of the
transition is reached, the sharp peaks in the ARPES spectra are completely
suppressed. Since the resistance onset is a signature of phase fluctuations,
this implies that the loss of single-particle coherence is connected with the
loss of long-range phase coherence.Comment: 7 pages, 7 figure
Quasiparticles dynamics in high-temperature superconductors far from equilibrium: an indication of pairing amplitude without phase coherence
We perform time resolved photoelectron spectroscopy measurements of optimally
doped \tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta} (Bi-2212) and
\tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta} (Bi-2201). The
electrons dynamics show that inelastic scattering by nodal quasiparticles
decreases when the temperature is lowered below the critical value of the
superconducting phase transition. This drop of electronic dissipation is
astonishingly robust and survives to photoexcitation densities much larger than
the value sustained by long-range superconductivity. The unconventional
behaviour of quasiparticle scattering is ascribed to superconducting
correlations extending on a length scale comparable to the inelastic path. Our
measurements indicate that strongly driven superconductors enter in a regime
without phase coherence but finite pairing amplitude. The latter vanishes near
to the critical temperature and has no evident link with the pseudogap observed
by Angle Resolved Photoelectron Spectroscopy (ARPES).Comment: 7 pages, 5 Figure
Protected nodes and the collapse of the Fermi arcs in high Tc cuprates
Angle resolved photoemission on underdoped Bi2Sr2CaCu2O8 reveals that the
magnitude and d-wave anisotropy of the superconducting state energy gap are
independent of temperature all the way up to Tc. This lack of T variation of
the entire k-dependent gap is in marked contrast to mean field theory. At Tc
the point nodes of the d-wave gap abruptly expand into finite length ``Fermi
arcs''. This change occurs within the width of the resistive transition, and
thus the Fermi arcs are not simply thermally broadened nodes but rather a
unique signature of the pseudogap phase.Comment: Accepted by Phys. Rev. Let
Pairing in cuprates from high energy electronic states
The in-plane optical conductivity of Bi2Sr2CaCu2O8+d thin films with small
carrier density (underdoped) up to large carrier density (overdoped) is
analyzed with unprecedented accuracy. Integrating the conductivity up to
increasingly higher energies points to the energy scale involved when the
superfluid condensate builds up. In the underdoped sample, states extending up
to 2 eV contribute to the superfluid. This anomalously large energy scale may
be assigned to a change of in-plane kinetic energy at the superconducting
transition, and is compatible with an electronic pairing mechanism.Comment: 11 pages, 3 figure
The change of Fermi surface topology in Bi2Sr2CaCu2O8 with doping
We report the observation of a change in Fermi surface topology of
Bi2Sr2CaCu2O8 with doping. By collecting high statistics ARPES data from
moderately and highly overdoped samples and dividing the data by the Fermi
function, we answer a long standing question about the Fermi surface shape of
Bi2Sr2CaCu2O8 close to the (pi,0) point. For moderately overdoped samples
(Tc=80K) we find that both the bonding and antibonding sheets of the Fermi
surface are hole-like. However for a doping level corresponding to Tc=55K we
find that the antibonding sheet becomes electron-like. This change does not
directly affect the critical temperature and therefore the superconductivity.
However, since similar observations of the change of the topology of the Fermi
surface were observed in LSCO and Bi2Sr2Cu2O6, it appears to be a generic
feature of hole-doped superconductors. Because of bilayer splitting, though,
this doping value is considerably lower than that for the single layer
materials, which again argues that it is unrelated to Tc
Critical temperature for first-order phase transitions in confined systems
We consider the Euclidean -dimensional
() model with () compactified dimensions.
Introducing temperature by means of the Ginzburg--Landau prescription in the
mass term of the Hamiltonian, this model can be interpreted as describing a
first-order phase transition for a system in a region of the -dimensional
space, limited by pairs of parallel planes, orthogonal to the coordinates
axis . The planes in each pair are separated by distances
. We obtain an expression for the transition temperature as
a function of the size of the system, , . For
D=3 we particularize this formula, taking for the
physically interesting cases (a film), (an infinitely long wire
having a square cross-section), and for (a cube). For completeness, the
corresponding formulas for second-order transitions are also presented.
Comparison with experimental data for superconducting films and wires shows
qualitative agreement with our theoretical expressionsComment: REVTEX, 11 pages, 3 figures; to appear in Eur. Phys. Journal
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