8,605 research outputs found
Universality of Low-Energy Scattering in 2+1 Dimensions: The Non Symmetric Case
For a very large class of potentials, , , we
prove the universality of the low energy scattering amplitude, . The result is . The
only exceptions occur if happens to have a zero energy bound state. Our new
result includes as a special subclass the case of rotationally symmetric
potentials, .Comment: 65 pages, Latex, significant changes, new sections and appendice
Nano-Kelvin thermometry and temperature control: beyond the thermal noise limit
We demonstrate thermometry with a resolution of 80 using an isotropic crystalline whispering-gallery mode
resonator based on a dichroic dual-mode technique. We simultaneously excite two
modes that have a mode frequency ratio very close to two (ppm). The
wavelength- and temperature-dependence of the refractive index means that the
frequency difference between these modes is an ultra-sensitive proxy of the
resonator temperature. This approach to temperature sensing automatically
suppresses sensitivity to thermal expansion and vibrationally induced changes
of the resonator. We also demonstrate active suppression of temperature
fluctuations in the resonator by controlling the intensity of the driving
laser. The residual temperature fluctuations are shown to be below the limits
set by fundamental thermodynamic fluctuations of the resonator material
Correlated electrons systems on the Apollonian network
Strongly correlated electrons on an Apollonian network are studied using the
Hubbard model. Ground-state and thermodynamic properties, including specific
heat, magnetic susceptibility, spin-spin correlation function, double occupancy
and one-electron transfer, are evaluated applying direct diagonalization and
quantum Monte Carlo. The results support several types of magnetic behavior. In
the strong-coupling limit, the quantum anisotropic spin 1/2 Heisenberg model is
used and the phase diagram is discussed using the renormalization group method.
For ferromagnetic coupling, we always observe the existence of long-range
order. For antiferromagnetic coupling, we find a paramagnetic phase for all
finite temperatures.Comment: 7 pages, 8 figure
Immigration and social exclusion : examining health inequalities of immigrants through acculturation lenses
Over the last three decades, the number of people migrating from developing to
developed countries has been increasing in stepwise fashion as a result of
insecurity, war and poverty. Such mass population movement has resulted in
dramatic demographic transformations of most developed countries (Organisation
for Economic Co-operation and Development 2007). The latest demographic data indicate that about 4 million new immigrants entered OECD countries on a permanent basis in 2005, an increase of 10 per cent from 2004 (Organisation for Economic Co-operation and Development 2007). In Australia, the 2006 census data indicate that more than one in five Australians (22.2 per cent) were born overseas, a pattern that has remained constant since 1996. The overseas-born population increased in number between 1996 and 2006 by 13 per cent, from around 3.9 million to 4.4 million (Australian Bureau of Statistics 2007d). Although a considerable proportion of Australian residents born overseas (including refugees and humanitarian entrants) come from countries recently affected by war and political unrest (Australian Bureau of Statistics 2007d), at a global level, migration for family reunion is the dominant reason for the inflows, and labour immigration is expanding, while humanitarian migration (including refugees and asylum seekers) has been declining (Organisation for Economic Co-operation and Development 2007)
Ferromagnetism and the Effect of Free Charge Carriers on Electric Polarization in Y_2NiMnO_6 Double Perovskite
The double perovskite Y_2NiMnO_6 displays ferromagnetic transition at Tc = 81
K. The ferromagnetic order at low temperature is confirmed by the saturation
value of magnetization (M_s) and also, validated by the refined ordered
magnetic moment values extracted from neutron powder diffraction data at 10 K.
This way, the dominant Mn4+ and Ni2+ cationic ordering is confirmed. The
cation-ordered P 21/n nuclear structure is revealed by neutron powder
diffraction studies at 300 and 10 K. Analysis of frequency dependent dielectric
constant and equivalent circuit analysis of impedance data takes into account
the bulk contribution to total dielectric constant. This reveals an anomaly
which coincides with the ferromagnetic transition temperature (T_c).
Pyrocurrent measurements register a current flow with onset near Tc and a peak
at 57 K that shifts with temperature ramp rate. The extrinsic nature of the
observed pyrocurrent is established by employing a special protocol
measurement. It is realized that the origin is due to re-orientation of
electric dipoles created by the free charge carriers and not by spontaneous
electric polarization at variance with recently reported magnetism-driven
ferroelectricity in this materialComment: Published in Physical Review
Associations of womens position in the household and food insecurity with family planning use in Nepal.
BACKGROUND: Women in Nepal have low status, especially younger women in co-resident households. Nepal also faces high levels of household food insecurity and malnutrition, and stagnation in uptake of modern family planning methods. OBJECTIVE: This study aims to understand if household structure and food insecurity interact to influence family planning use in Nepal. METHODS: Using data on married, non-pregnant women aged 15-49 with at least one child from the Nepal 2011 Demographic and Health Survey (N = 7,460), we explore the relationship between womens position in the household, food insecurity as a moderator, and family planning use, using multi-variable logistic regressions. We adjust for household and individual factors, including other status-related variables. RESULTS: In adjusted models, living in a food insecure household and co-residing with in-laws either with no other daughter-in-laws or as the eldest or youngest daughter-in-law (compared to not-co-residing with in-laws) are all associated with lower odds of family planning use. In the interaction model, younger-sisters-in-law and women co-residing with no sisters-in-law in food insecure households have the lowest odds of family planning use. CONCLUSION: This study shows that household position is associated with family planning use in Nepal, and that food insecurity modifies these associations-highlighting the importance of considering both factors in understanding reproductive health care use in Nepal. Policies and programs should focus on the multiple pathways through which food insecurity impacts womens reproductive health, including focusing on women with the lowest status in households
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