148 research outputs found
Dark Universe and distribution of Matter as Quantum Imprinting: the Quantum Origin of Universe
In this paper we analyze the Dark Matter problem and the distribution of
matter through two different approaches, which are linked by the possibility
that the solution of these astronomical puzzles should be sought in the quantum
imprinting of the Universe. The first approach is based on a cosmological model
formulated and developed in the last ten years by the first and third authors
of this paper; the so-called Archaic Universe. The second approach was
formulated by Rosen in 1933 by considering the Friedmann-Einstein equations as
a simple one-dimensional dynamical system reducing the cosmological equations
in terms of a Schroedinger equation. As an example, the quantum memory in
cosmological dynamics could explain the apparently periodic structures of the
Universe while Archaic Universe shows how the quantum phase concernts not only
an ancient era of the Universe, but quantum facets permeating the entire
Universe today.Comment: 18 page
Noise thermometry in narrow 2D electron gas heat baths connected to a quasi-1D interferometer
Thermal voltage noise measurements are performed in order to determine the
electron temperature in nanopatterned channels of a GaAs/AlGaAs heterostructure
at bath temperatures of 4.2 and 1.4 K. Two narrow two-dimensional (2D) heating
channels, close to the transition to the one-dimensional (1D) regime, are
connected by a quasi-1D quantum interferometer. Under dc current heating of the
electrons in one heating channel, we perform cross-correlated noise
measurements locally in the directly heated channel and nonlocally in the other
channel, which is indirectly heated by hot electron diffusion across the
quasi-1D connection. We observe the same functional dependence of the thermal
noise on the heating current. The temperature dependence of the electron
energy-loss rate is reduced compared to wider 2D systems. In the quantum
interferometer, we show the decoherence due to the diffusion of hot electrons
from the heating channel into the quasi-1D system, which causes a thermal
gradient.Comment: 6 pages, 5 figure
Magnetoelectric effects in an organo-metallic quantum magnet
We observe a bilinear magnetic field-induced electric polarization of 50 in single crystals of NiCl-4SC(NH) (DTN). DTN forms a
tetragonal structure that breaks inversion symmetry, with the highly polar
thiourea molecules all tilted in the same direction along the c-axis.
Application of a magnetic field between 2 and 12 T induces canted
antiferromagnetism of the Ni spins and the resulting magnetization closely
tracks the electric polarization. We speculate that the Ni magnetic forces
acting on the soft organic lattice can create significant distortions and
modify the angles of the thiourea molecules, thereby creating a magnetoelectric
effect. This is an example of how magnetoelectric effects can be constructed in
organo-metallic single crystals by combining magnetic ions with electrically
polar organic elements.Comment: 3 pages, 3 figure
Genetic variability of the ovine αs1-casein
The casein genetic polymorphisms are important for their effects on quantitative traits and technological properties of milk. At the αs1-casein (CSN1S1) level three genetic variants were characterised (A, C, D) in ovine milk (Ferranti et al., 1995)
Characterization of the casein gene complex in West Africa goats and description of a new αs1-casein polymorphism
The analysis of casein polymorphisms was carried
out in West Africa goat populations: Red Sokoto (n =
57), West African Dwarf Nigeria (n = 27), West African
Dwarf Cameroon (n = 39), and Borno (n = 37). The 4
casein genes alphas1 (CSN1S1), beta (CSN2), alphas2 (CSN1S2), and kappa (CSN3) were typed at the DNA level. No null alleles were found in any of the genes analyzed. A PCR single-strand conformation polymorphism method was
implemented for the identification of CSN1S1*F allele
simultaneously with A/01, B/E, N and the new allele.
The allele differed from CSN1S1*B by a synonymous
transversion TCG->TCT in the codon corresponding to
Ser66 of the mature protein. The new allele, named
CSN1S1*B', occurred at a high frequency in all the
populations, ranging from 0.295 (West African Dwarf
Cameroon) to 0.405 (Borno). A greater frequency was
found for alleles associated with high alphas1-casein quantity,
as has already been observed in the goat populations
from the Mediterranean area. The intermediate
E allele occurred only in the Red Sokoto and at a low
frequency. The faint F allele occurred in 3 populations
at frequencies lower than 0.03. Linkage disequilibrium
occurred in all the populations, with highly significant
differences in Borno, Red Sokoto, and West Africa
Dwarf Nigeria, and significant differences in West Africa
Dwarf Cameroon. Only 10 haplotypes showed frequencies
>= 0.05 in at least 1 of the 4 populations considered,
and the overall frequency was >0.1 only for 4
haplotypes: BAAB, B'ACA, ACAB, and BACA (in the
order CSN1S1-CSN2-CSN1S2-CSN3). Haplotype
BAAB, postulated as an ancestral haplotype in previous
studies, was the most common haplotype in all breeds
except Borno, where B'ACA was predominant. The results
obtained are of considerable significance given that very little information exists on the subject for African goats. The high frequency of strong alleles in the calcium-sensitive caseins as well as the high linkage disequilibrium found among the casein genes in the African breeds analyzed may suggest that specific casein haplotypes have already been selected due to their advantages for nutrition. Haplotypes providing greater
protein and casein content would increase the energy
content of milk, thus resulting in more favorable growth
and survival of young goats and humans consuming
the milk
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