8,466 research outputs found
Pluri-Canonical Models of Supersymmetric Curves
This paper is about pluri-canonical models of supersymmetric (susy) curves.
Susy curves are generalisations of Riemann surfaces in the realm of super
geometry. Their moduli space is a key object in supersymmetric string theory.
We study the pluri-canonical models of a susy curve, and we make some
considerations about Hilbert schemes and moduli spaces of susy curves.Comment: To appear in the proceedings of the intensive period "Perspectives in
Lie Algebras", held at the CRM Ennio De Giorgi, Pisa, Italy, 201
Characterization and wear performance of boride phases over tool steel substrates
This research work was conducted to characterize boride phases, obtained from the powder-pack process, on AISI H13 and D2 steel substrates, and investigate their tribological behavior. The boriding was developed at a temperature of 1273 K with an exposure time of 8 h. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were conducted on the borided material to characterize the presence of the FeB, Fe2B, and CrB phases and the distribution of heavy elements on the surface of the substrates. The adherence of the boride layers was evaluated, in a qualitative form, through the Daimler-Benz Rockwell-C indentation technique. Sliding wear tests were then performed using a reciprocating wear test machine. All tests were conducted in dry conditions at room temperature. A frequency of 10 Hz and 15-mm sliding distance were used. The applied Hertzian pressure was 2.01 GPa. Scanning electron microscopy was used to observe and analyze the wear mechanisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. Experimental results showed that the characteristic wear mechanism for the borided surface was plastic deformation and mild abrasive wear; for unborided substrates, cracking and spalling were observed
Localized magnetic plasmons in all-dielectric mu<0 metastructures
Metamaterials are known to exhibit a variety of electromagnetic properties
non-existing in nature. We show that an all-dielectric (non-magnetic) system
consisting of deep subwavelength, high permittivity resonant spheres possess
effective negative magnetic permeability (dielectric permittivity being
positive and small). Due to the symmetry of the electromagnetic wave equations
in classical electrodynamics, localized "magnetic" plasmon resonances can be
excited in a metasphere made of such metamaterial. This is theoretically
demonstrated by the coupled-dipole approximation and numerically for real
spheres, in full agreement with the exact analytical solution for the
scattering process by the same metasphere with effective material properties
predicted by effective medium theory. The emergence of this phenomenon as a
function of structural order within the metastructures is also studied.
Universal conditions enabling effective negative magnetic permeability relate
subwavelength sphere permittivity and size with critical filling fraction. Our
proposal paves the way towards (all-dielectric) magnetic plasmonics, with a
wealth of fascinating applications.Comment: 7 pages, 4 figures; figure 3 modified and new figure (4) added, with
corresponding discussio
Use of deoxycorticosterone pivalate by veterinarians: A western european survey
open9siThis research was supported by FCT—Fundação para a Ciência e Tecnologia IP, grant UIDB/00276/2020This study aims to gather knowledge about the use of deoxycorticosterone pivalate (DOCP) by Western European Veterinarians (WEV) in dogs with typical hypoadrenocorticism. An observa-tional cross-sectional study was conducted using an online survey, translated into four languages and disseminated to veterinary affiliates and mailing lists in six countries of Western Continental Europe. Respondents were tasked to share their therapeutic approach to hypoadrenocorticism, whether they preferred DOCP or fludrocortisone and the specific practical use of DOCP. One-hundred and eighty-four responses were included. Of these, 79.9% indicated that they preferred prescribing DOCP over fludrocortisone as a first-line treatment for mineralocorticoid supplementation. A total of 154 respondents had used DOCP at least once. Eighty percent of those who reported their initial dosage prescribed 2.2 mg/kg. After starting DOCP, 68.2% of the respondents assess electrolytes 10 and 25 days after administration following manufacturer instructions. In stable dogs, electrolytes are monitored quarterly, monthly, semi-annually, and annually by 44.2%, 34.4%, 16.9%, and 4.6% of respondents respectively. When treatment adjustment is required, 53% prefer to reduce dosage while 47% increase the interval between doses. Overall, DOCP is the preferred mineralocorticoid supple-mentation among WEV. Reported variability underlies the need to investigate the best strategies for DOCP use and therapeutic adjustments.openRebocho R.; Dominguez-Ruiz M.; Englar R.E.; Arenas C.; Perez-Alenza M.D.; Corsini A.; Fracassi F.; Bennaim M.; Leal R.O.Rebocho R.; Dominguez-Ruiz M.; Englar R.E.; Arenas C.; Perez-Alenza M.D.; Corsini A.; Fracassi F.; Bennaim M.; Leal R.O
Self-control in Sparsely Coded Networks
A complete self-control mechanism is proposed in the dynamics of neural
networks through the introduction of a time-dependent threshold, determined in
function of both the noise and the pattern activity in the network. Especially
for sparsely coded models this mechanism is shown to considerably improve the
storage capacity, the basins of attraction and the mutual information content
of the network.Comment: 4 pages, 6 Postscript figure
Seasonal variations of carcass characteristics, meat quality and nutrition value in iberian wild red deer
Aim of study: The effects of hunting season (autumn vs. winter) on carcass characteristics and meat quality of Iberian wild red deer were assessed. Area of study: A total of 100 males of wild red deer of Iberian genetic line (Cervus elaphus) were hunted on Ciudad Real (south central Spain). Material and methods: Yields for shoulder (with bone), neck, backbone, loin, tenderloin, leg (with bone), short plate and flank were determined. In addition, samples of Longissimus thoracis et lumborum and Rectus abdominis muscles were collected. Then, pH48, colour measurements, chemical composition, cooking loss, Warner Bratzler shear blade, fatty acid and amino acid profiles and mineral content were analyzed. Main results: Deer hunted in autumn (n=50) had higher (p<0.01) yields of shoulder, backbone and short plate and higher contents of intramuscular fat (IMF), cholesterol and K, Fe and Mn but lower (p<0.001) pH48 and Na, Mg, Zn and Cu contents than deer hunted in winter (n=50). Shear force tended (p=0.05) to be lower for meat collected in autumn than for meat collected in winter. However, loin yield was 59.2% higher (p<0.001) for winter than for autumn carcasses. Deer hunted in winter had higher α-linoleic acid (p<0.05) and long chain n-3 polyunsaturated (p<0.001) percentages than deer hunted in autumn Research highlights: Autumn hunting is recommended to obtain carcasses with higher yields of shoulder, backbone and short plate and meat with higher IMF. Conversely, winter hunting is advisable for higher loin yield and for a profile richer in polyunsaturated fatty acids
Clinical subgroups in bilateral meniere disease
Meniere disease (MD) is a heterogeneous clinical condition characterized by sensorineural hearing loss, episodic vestibular symptoms, and tinnitus associated with several comorbidities, such as migraine or autoimmune disorders (AD). The frequency of bilateral involvement may range from 5 to 50%, and it depends on the duration of the disease. We have performed a two-step cluster analysis in 398 patients with bilateral MD (BMD) to identify the best predictors to define clinical subgroups with a potential different etiology to improve the phenotyping of BMD and to develop new treatments. We have defined five clinical variants in BMD. Group 1 is the most frequently found, includes 46% of patients, and is defined by metachronic hearing loss without migraine and without AD. Group 2 is found in 17% of patients, and it is defined by synchronic hearing loss without migraine or AD. Group 3, with 13% of patients, is characterized by familial MD, while group 4, that includes 12% of patients, is associated by the presence of migraine in all cases. Group 5 is found in 11% of patients and is defined by AD. This approach can be helpful in selecting patients for genetic and clinical research. However, further studies will be required to improve the phenotyping in these clinical variants for a better understanding of the diverse etiological factors contributing to BMD
Coupled Maps on Trees
We study coupled maps on a Cayley tree, with local (nearest-neighbor)
interactions, and with a variety of boundary conditions. The homogeneous state
(where every lattice site has the same value) and the node-synchronized state
(where sites of a given generation have the same value) are both shown to occur
for particular values of the parameters and coupling constants. We study the
stability of these states and their domains of attraction. As the number of
sites that become synchronized is much higher compared to that on a regular
lattice, control is easier to effect. A general procedure is given to deduce
the eigenvalue spectrum for these states. Perturbations of the synchronized
state lead to different spatio-temporal structures. We find that a mean-field
like treatment is valid on this (effectively infinite dimensional) lattice.Comment: latex file (25 pages), 4 figures included. To be published in Phys.
Rev.
The dust content of high-z submillimeter galaxies revealed by Herschel
We use deep observations taken with the Photodetector Array Camera and
Spectrometer (PACS), on board the Herschel satellite as part of the PACS
evolutionary probe (PEP) guaranteed project along with submm ground-based
observations to measure the dust mass of a sample of high-z submillimeter
galaxies (SMGs). We investigate their dust content relative to their stellar
and gas masses, and compare them with local star-forming galaxies. High-z SMGs
are dust rich, i.e. they have higher dust-to-stellar mass ratios compared to
local spiral galaxies (by a factor of 30) and also compared to local
ultraluminous infrared galaxies (ULIRGs, by a factor of 6). This indicates that
the large masses of gas typically hosted in SMGs have already been highly
enriched with metals and dust. Indeed, for those SMGs whose gas mass is
measured, we infer dust-to-gas ratios similar or higher than local spirals and
ULIRGs. However, similarly to other strongly star-forming galaxies in the local
Universe and at high-z, SMGs are characterized by gas metalicities lower (by a
factor of a few) than local spirals, as inferred from their optical nebular
lines, which are generally ascribed to infall of metal-poor gas. This is in
contrast with the large dust content inferred from the far-IR and submm data.
In short, the metalicity inferred from the dust mass is much higher (by more
than an order of magnitude) than that inferred from the optical nebular lines.
We discuss the possible explanations of this discrepancy and the possible
implications for the investigation of the metalicity evolution at high-z.Comment: Accepted for publication in Astronomy & Astrophysics Letters. One
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