997 research outputs found
Nonlinear modes in the harmonic PT-symmetric potential
We study the families of nonlinear modes described by the nonlinear
Schr\"odinger equation with the PT-symmetric harmonic potential . The found nonlinear modes display a number of interesting features. In
particular, we have observed that the modes, bifurcating from the different
eigenstates of the underlying linear problem, can actually belong to the same
family of nonlinear modes. We also show that by proper adjustment of the
coefficient it is possible to enhance stability of small-amplitude and
strongly nonlinear modes comparing to the well-studied case of the real
harmonic potential.Comment: 7 pages, 2 figures; accepted to Phys. Rev.
Calorimetric Measurements of Magnetic-Field-Induced Inhomogeneous Superconductivity Above The Paramagnetic Limit
We report the first magneto-caloric and calorimetric observations of a
magnetic-field-induced phase transition within a superconducting state to the
long-sought exotic "FFLO" superconducting state first predicted over 50 years
ago. Through the combination of bulk thermodynamic calorimetric and
magnetocaloric measurements in the organic superconductor -
(BEDT-TTF)Cu(NCS), as a function of temperature, magnetic field
strength, and magnetic field orientation, we establish for the first time that
this field-induced first-order phase transition at the paramagnetic limit
for traditional superconductivity is to a higher entropy superconducting phase
uniquely characteristic of the FFLO state. We also establish that this
high-field superconducting state displays the bulk paramagnetic ordering of
spin domains required of the FFLO state. These results rule out the alternate
possibility of spin-density wave (SDW) ordering in the high field
superconducting phase. The phase diagram determined from our measurements ---
including the observation of a phase transition into the FFLO phase at
--- is in good agreement with recent NMR results and our own earlier
tunnel-diode magnetic penetration depth experiments, but is in disagreement
with the only previous calorimetric report.Comment: 5 pages, 5 figure
Reduced mitochondrial efficiency explains mismatched growth and metabolic rate at supraoptimal temperatures.
The relationship between whole-organism growth and metabolism is generally assumed to be positive and causative; higher metabolic rates support higher growth rates. In Manduca sexta, existing data demonstrate a deviation from this simple prediction: at supraoptimal temperatures for larval growth, metabolic rate keeps increasing while growth rate is decreasing. This mismatch presumably reflects the rising “cost of maintenance” with temperature. Precisely what constitutes this cost is not clear, but we suspect the efficiency with which mitochondria harness oxygen and organic substrates into cellular energy (ATP) is key. We tested this by integrating existing data on M. sexta growth and metabolism with new data on mitochondrial bioenergetics across the temperature range 14°–42°C. Across this range, our measure of mitochondrial efficiency closely paralleled larval growth rates. At supraoptimal temperatures for growth, mitochondrial efficiency was reduced, which could explain the mismatch between growth and metabolism observed at the whole-organism level
Upper critical field study in the organic superconductor -(ET)SFCHCFSO : Possibility of Fulde-Ferrell-Larkin-Ovchinnikov state
We report upper critical field measurements in the metal-free-all-organic
superconductor -(ET)SFCHCFSO obtained
from measuring the in-plane penetration depth using the tunnel diode oscillator
technique. For magnetic field applied parallel to the conducting planes the low
temperature upper critical fields are found to exceed the Pauli limiting field
calculated by using a semi-empirical method. Furthermore, we found a signature
that could be the phase transition between the superconducting vortex state and
the Fulde-Ferrell-Larkin-Ovchinnikov state in the form of a kink just below the
upper critical field and only at temperatures below 1.23 K.Comment: 4 pages, 6 figure
The Land Cadastre in Italy and some fiscal implications: a case study
The Land Cadastre, as an inventory of all relevant real estate in a territory, and most importantly, as a national tax system is, or at least should be, the protago-nist of fiscal, social and civil implications affecting the Italian context. According to unitary farmland incomes, the last revision dates back to 1978-1979, a period that no longer reflects the country’s current socioeconomic situation and does not consider the changes the land market has undergone over the years. Through the analysis of 183 purchases and sales of agricultural land in two districts in western Sicily, this research aims at verifying the adequacy or inadequacy of the current cadastral tariffs. Based on the prices surveyed and the cadastral farmland incomes, some indicators were constructed showing, on the one hand the absence of a strict correspondence between these two values and on the other hand the actual presence of fiscal ine-quality for all the crop qualities examined; and, consequently, the need for revising cadastral tariffs or for reforming tax system of Italian Cadastre by replacing tariffs with market values
A Macrophysiological Analysis of Energetic Constraints on Geographic Range Size in Mammals
Physiological processes are essential for understanding the distribution and abundance of organisms, and recently, with widespread attention to climate change, physiology has been ushered back to the forefront of ecological thinking. We present a macrophysiological analysis of the energetics of geographic range size using combined data on body size, basal metabolic rate (BMR), phylogeny and range properties for 574 species of mammals. We propose three mechanisms by which interspecific variation in BMR should relate positively to geographic range size: (i) Thermal Plasticity Hypothesis, (ii) Activity Levels/Dispersal Hypothesis, and (iii) Energy Constraint Hypothesis. Although each mechanism predicts a positive correlation between BMR and range size, they can be further distinguished based on the shape of the relationship they predict. We found evidence for the predicted positive relationship in two dimensions of energetics: (i) the absolute, mass-dependent dimension (BMR) and (ii) the relative, mass-independent dimension (MIBMR). The shapes of both relationships were similar and most consistent with that expected from the Energy Constraint Hypothesis, which was proposed previously to explain the classic macroecological relationship between range size and body size in mammals and birds. The fact that this pattern holds in the MIBMR dimension indicates that species with supra-allometric metabolic rates require among the largest ranges, above and beyond the increasing energy demands that accrue as an allometric consequence of large body size. The relationship is most evident at high latitudes north of the Tropics, where large ranges and elevated MIBMR are most common. Our results suggest that species that are most vulnerable to extinction from range size reductions are both large-bodied and have elevated MIBMR, but also, that smaller species with elevated MIBMR are at heightened risk. We also provide insights into the global latitudinal trends in range size and MIBMR and more general issues of phylogenetic and geographic scale
A bulk 2D Pauli Limited Superconductor
We present a nearly perfect Pauli-limited critical field phase diagram for
the anisotropic organic superconductor \-(ET)NH(SCN) when
the applied magnetic field is oriented parallel to the conducting layers. The
critical fields ({H_{c_2}) were found by use of penetration depth
measurements. Because {H_{c_2} is Pauli-limited, the size of the
superconducting energy gap can be calculated. The role of spin-orbit scattering
and many-body effects play a role in explaining our measurements.Comment: 4 pages, 5 figures. V5, corrections were made to the text, present
data was include
- …