1,911 research outputs found
Sex assignment in conditions affecting sex development
The newborn infant with atypical genitalia presents a challenging clinical scenario and requires expert input. There have been appreciable advances in our knowledge of the underlying causes that may lead to a mere difference or a more serious disorder of sex development (DSD), the natural history of conditions, as well as the short and long-term complications of these conditions themselves, together with the clinical interventions that are associated with these conditions. With this information, the DSD expert can be more confident when discussing options with the parents of the newborn infant. By working within a multidisciplinary team, the expert should be able to support the family whilst individualising the management plan so that it is also cognizant of the shifts in societal attitudes and expectations around concepts of diversity and openness. It is, therefore, likely that the practice of assigning sex, especially in those cases where sex assignment is unclear on expert assessment, will continue to show temporal, social and geographical variations. It is imperative that clinical data for rare conditions such as these are collected in a standardized format and shared through a common registry so that any evidence that is used for future shifts in practice has a stronger foundation than that which is currently available
High order fluid model for streamer discharges. II. Numerical solution and investigation of planar fronts
The high order fluid model developed in the preceding paper is employed here
to study the propagation of negative planar streamer fronts in pure nitrogen.
The model consists of the balance equations for electron density, average
electron velocity, average electron energy and average electron energy flux.
These balance equations have been obtained as velocity moments of Boltzmann's
equation and are here coupled to the Poisson equation for the space charge
electric field. Here the results of simulations with the high order model, with
a PIC/MC (Particle in cell/Monte Carlo) model and with the first order fluid
model based on the hydrodynamic drift-diffusion approximation are presented and
compared. The comparison with the MC model clearly validates our high order
fluid model, thus supporting its correct theoretical derivation and numerical
implementation. The results of the first order fluid model with local field
approximation, as usually used for streamer discharges, show considerable
deviations. Furthermore, we study the inaccuracies of simulation results caused
by an inconsistent implementation of transport data into our high order fluid
model. We also demonstrate the importance of the energy flux term in the high
order model by comparing with results where this term is neglected. Finally,
results with an approximation for the high order tensor in the energy flux
equation is found to agree well with the PIC/MC results for reduced electric
fields up to 1000 Townsend, as considered in this work.Comment: 26 pages, 11 figure
Functional Foods in the Marketplace: Willingness to Pay for Apples Enriched with Antioxidants
The attention on so-called functional foods has been growing as consumers become more concerned with diet and nutrition. This article aims to measure consumers response to apples with naturally enriched antioxidant coatings. Surveys were conducted in grocery stores in Seattle, Washington and Spokane, Washington. The results suggest that consumers have a somewhat positive attitude towards functional foods in general and with apples enriched with antioxidants in particular. A contingent valuation technique was used to assess factors affecting consumers willingness to pay for the apples with antioxidant coatings. Consumers in the Spokane grocery stores are more likely to pay a premium for the new type of apples than consumers in Seattle. Consumers who look for a wide variety of product in choosing where to shop for food are more likely to pay a premium for apples enriched with antioxidants. Also, it is estimated that consumers, on average, are willing to pay from 4% to 8% premium for these apples.functional food, willingness to pay, antioxidants, Demand and Price Analysis, Health Economics and Policy,
Investigating the relationship between material properties and laser-induced damage threshold of dielectric optical coatings at 1064 nm
The Laser Induced Damage Threshold (LIDT) and material properties of various multi-layer amorphous dielectric
optical coatings, including Nb2O5, Ta2O5, SiO2, TiO2, ZrO2, AlN, SiN, LiF and ZnSe, have been studied. The coatings
were produced by ion assisted electron beam and thermal evaporation; and RF and DC magnetron sputtering at Helia
Photonics Ltd, Livingston, UK. The coatings were characterized by optical absorption measurements at 1064 nm by
Photothermal Common-path Interferometry (PCI). Surface roughness and damage pits were analyzed using atomic force
microscopy. LIDT measurements were carried out at 1064 nm, with a pulse duration of 9.6 ns and repetition rate of 100
Hz, in both 1000-on-1 and 1-on-1 regimes. The relationship between optical absorption, LIDT and post-deposition heattreatment
is discussed, along with analysis of the surface morphology of the LIDT damage sites showing both coating
and substrate failure
Comparison of single-layer and double-layer anti-reflection coatings using laser-induced damage threshold and photothermal common-path interferometry
The dielectric thin-film coating on high-power optical components is often the weakest region and will fail at elevated optical fluences. A comparison of single-layer coatings of ZrO2, LiF, Ta2O5, SiN, and SiO2 along with anti-reflection (AR) coatings optimized at 1064 nm comprised of ZrO2 and Ta2O5 was made, and the results of photothermal common-path interferometry (PCI) and a laser-induced damage threshold (LIDT) are presented here. The coatings were grown by radio frequency (RF) sputtering, pulsed direct-current (DC) sputtering, ion-assisted electron beam evaporation (IAD), and thermal evaporation. Test regimes for LIDT used pulse durations of 9.6 ns at 100 Hz for 1000-on-1 and 1-on-1 regimes at 1064 nm for single-layer and AR coatings, and 20 ns at 20 Hz for a 200-on-1 regime to compare the //ZrO2/SiO2 AR coating
Exchange Interactions in a Dinuclear Manganese (II) Complex with Cyanopyridine-N-oxide Bridging Ligands
The structure and magnetic properties of oligonuclear manganese complex
[Mn(hfa)2cpo]2 (where hfa is hexafluoroacetylacetonate dehydrate and cpo is
4-cyanopyridine-N-oxide) are presented. In the unit cell, the dinuclear
molecules are well isolated from each other. The non-monotonous dependence of
magnetic susceptibility is explained in terms of the hierarchy of exchange
parameters by using exact diagonalization. The thermodynamic behavior of pure
cpo and [Mn(hfa)2(cpo)]2 is simulated numerically in a dimer approximation by
an extrapolation to spin S = 5/2. The Mn-Mn exchange integral is evaluated.Comment: Final corrected version, pdf, 12 page
Optical absorption of ion-beam sputtered amorphous silicon coatings
Low mechanical loss at low temperatures and a high index of refraction should make silicon
optimally suited for thermal noise reduction in highly reflective mirror coatings for gravitational wave
detectors. However, due to high optical absorption, amorphous silicon (aSi) is unsuitable for being used
as a direct high-index coating material to replace tantala. A possible solution is a multimaterial design,
which enables exploitation of the excellent mechanical properties of aSi in the lower coating layers. The
possible number of aSi layers increases with absorption reduction. In this work, the optimum heat
treatment temperature of aSi deposited via ion-beam sputtering was investigated and found to be 450 °C.
For this temperature, the absorption after deposition of a single layer of aSi at 1064 nm and 1550 nm
was reduced by more than 80%
Magnetic Properties of J-J-J' Quantum Heisenberg Chains with Spin S=1/2, 1, 3/2 and 2 in a Magnetic Field
By means of the density matrix renormalization group (DMRG) method, the
magnetic properties of the J-J-J quantum Heisenberg chains with spin
, 1, 3/2 and 2 in the ground states are investigated in the presence of
a magnetic field. Two different cases are considered: (a) when is
antiferromagnetic and is ferromagnetic (i.e. the AF-AF-F chain),
the system is a ferrimagnet. The plateaus of the magnetization are observed. It
is found that the width of the plateaus decreases with increasing the
ferromagnetic coupling, and disappears when passes over a
critical value. The saturated field is observed to be independent of the
ferromagnetic coupling; (b) when is ferromagnetic and is
antiferromagnetic (i.e. the F-F-AF chain), the system becomes an
antiferromagnet. The plateaus of the magnetization are also seen. The width of
the plateaus decreases with decreasing the antiferromagnetic coupling, and
disappears when passes over a critical value. Though the ground
state properties are quite different, the magnetization plateaus in both cases
tend to disappear when the ferromagnetic coupling becomes more dominant.
Besides, no fundamental difference between the systems with spin half-integer
and integer has been found.Comment: 8 pages, 9 figures, to be published in J. Phys.: Condens. Matte
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