Unbiased Shape Compactness for Segmentation

We propose to constrain segmentation functionals with a dimensionless, unbiased and position-independent shape compactness prior, which we solve efficiently with an alternating direction method of multipliers (ADMM). Involving a squared sum of pairwise potentials, our prior results in a challenging high-order optimization problem, which involves dense (fully connected) graphs. We split the problem into a sequence of easier sub-problems, each performed efficiently at each iteration: (i) a sparse-matrix inversion based on Woodbury identity, (ii) a closed-form solution of a cubic equation and (iii) a graph-cut update of a sub-modular pairwise sub-problem with a sparse graph. We deploy our prior in an energy minimization, in conjunction with a supervised classifier term based on CNNs and standard regularization constraints. We demonstrate the usefulness of our energy in several medical applications. In particular, we report comprehensive evaluations of our fully automated algorithm over 40 subjects, showing a competitive performance for the challenging task of abdominal aorta segmentation in MRI.Comment: Accepted at MICCAI 201

Cosmological Constant and Noncommutativity: A Newtonian point of view

We study a Newtonian cosmological model in the context of a noncommutative space. It is shown that the trajectories of a test particle undergo modifications such that it no longer satisfies the cosmological principle. For the case of a positive cosmological constant, spiral trajectories are obtained and corrections to the Hubble constant appear. It is also shown that, in the limit of a strong noncommutative parameter, the model is closely related to a particle in a G\"odel-type metric.Comment: 14 pages, 3 figures, Introduction was changed and references added. Final version accepted for publication in JMPL

Low temperature microwave emission from molecular clusters

We investigate the experimental detection of the electromagnetic radiation generated in the fast magnetization reversal in Mn12-acetate at low temperatures. In our experiments we used large single crystals and assemblies of several small single crystals of Mn12-acetate placed inside a cylindrical stainless steel waveguide in which an InSb hot electron device was also placed to detect the radiation. All this was set inside a SQUID magnetometer that allowed to change the magnetic field and measure the magnetic moment and the temperature of the sample as the InSb detected simultaneously the radiation emitted from the molecular magnets. Our data show a sequential process in which the fast inversion of the magnetic moment first occurs, then the radiation is detected by the InSb device, and finally the temperature of the sample increases during 15 ms to subsequently recover its original value in several hundreds of milliseconds.Comment: changed conten

Secuenciación del ITS-1 del ADN ribosomal de Galba truncatula (Gastropoda, Lymnaeidae) y su impacto potencial en la transmisión de la fascioliasis en Mendoza, Argentina

Sequencing of the rDNA ITS–1 proved that the lymnaeid snail species Galba truncatula is present in Argentina and that it belongs to the haplotype HC, the same as that responsible for the fascioliasis transmission in the human hyperendemic area with the highest human prevalences and intensities known, the Northern Bolivian Altiplano.La secuenciación del ITS–1 del ADNr demostró que la especie de gasterópodo lymnaeido Galba truncatula se encuentra en Argentina y que pertenece al haplotipo HC, el mismo responsable de la transmisión de la fascioliasis en el área de hiperendemia humana con las mayores prevalencias e intensidades de fascioliasis conocidas, el Altiplano Norte Boliviano

Simian immunodeficiency virus infection in wild-caught chimpanzees from Cameroon

Simian immunodeficiency viruses (SIVcpz) infecting chimpanzees (Pan troglodytes) in west central Africa are the closest relatives to all major variants of human immunodeficiency virus type 1 ([HIV-1]; groups M, N and O), and have thus been implicated as the source of the human infections; however, information concerning the prevalence, geographic distribution, and subspecies association of SIVcpz still remains limited. In this study, we tested 71 wild-caught chimpanzees from Cameroon for evidence of SIVcpz infection. Thirty-nine of these were of the central subspecies (Pan troglodytes troglodytes), and 32 were of the Nigerian subspecies (Pan troglodytes vellerosus), as determined by mitochondrial DNA analysis. Serological analysis determined that one P. t. troglodytes ape (CAM13) harbored serum antibodies that cross-reacted strongly with HIV-1 antigens; all other apes were seronegative. To characterize the newly identified virus, 14 partially overlapping viral fragments were amplified from fecal virion RNA and concatenated to yield a complete SIVcpz genome (9,284 bp). Phylogenetic analyses revealed that SIVcpzCAM13 fell well within the radiation of the SIVcpzPtt group of viruses, as part of a clade including all other SIVcpzPtt strains as well as HIV-1 groups M and N. However, SIVcpzCAM13 clustered most closely with SIVcpzGAB1 from Gabon rather than with SIVcpzCAM3 and SIVcpzCAM5 from Cameroon, indicating the existence of divergent SIVcpzPtt lineages within the same geographic region. These data, together with evidence of recombination among ancestral SIVcpzPtt lineages, indicate long-standing endemic infection of central chimpanzees and reaffirm a west central African origin of HIV-1. Whether P. t. vellerosus apes are naturally infected with SIVcpz requires further study

Linfadenectomía inguinal robot asistida (LIRA) para cáncer de pene

ResumenIntroducciónEl carcinoma de células escamosas es una entidad que ocupa el 2-5% de los tumores urogenitales, siendo por tanto poco frecuente, sin embargo en instituciones como la nuestra y por un alto volumen de pacientes y centro de referencia, se logra tener entre 5-7 casos por año. Dentro del tratamiento de estas lesiones se encuentra la linfadenectomía inguinal, la cual en la actualidad es realizada con mayor frecuencia con mínima invasión. Presentamos el caso de un paciente con carcinoma epidermoide de pene al que se le realizó linfadenectomía inguinal superficial y profunda con cirugía robot asistida.ObjetivoDescribir la técnica quirúrgica para linfadenectomía inguinal robot asistida en cáncer de pene.Presentación del casoHombre de 73 años con padecimiento con un año y 6 meses de evolución con aumento de volumen a nivel del glande; previa toma de biopsia se le realizó penectomía radical con uretrostomía perineal con resultado histopatológico de carcinoma epidermoide bien diferenciado verrucoso que infiltra el cuerpo esponjoso y la uretra (T3, N0, M0, G1); se realizó linfadenectomía inguinal robot asistida a las 4 semanas.ConclusionesLa linfadenectomía inguinal robot asistida es una técnica factible en centros en los que se cuente con dicha tecnología, logrando disminuir la morbilidad, el sangrado y la estancia hospitalaria, sin embargo tiene como desventaja el costo del procedimiento.AbstractIntroductionSquamous cell carcinoma is a rare tumor, making up from 2 to 5% of the urogenital tumors. However, because our hospital is a referral center that manages large numbers of patients, approximately 5-7 cases are seen per year. Inguinal lymph node dissection is one of the treatments for these lesions and is being performed more frequently as a minimally invasive procedure.ObjectiveOur aim was to describe the surgical technique for robotic-assisted inguinal lymphadenectomy in cancer of the penis. We present herein the case of a 73-year-old man with symptom progression of one year and 6 months and increased volume at the level of the glans penis. A biopsy was taken, after which he underwent radical penectomy with perineal urethrostomy. The histopathologic study reported well differentiated verrucous squamous cell carcinoma that invaded the corpus spongiosum and the urethra (T3N0M0G1). Four weeks later he underwent robotic-assisted inguinal lymphadenectomy of the superficial and deep lymph nodes.ConclusionsRobotic-assisted inguinal lymphadenectomy, aside from its high cost, is a feasible technique when carried out in specialized centers that reduces morbidity, blood loss, and hospital stay

The one-loop elastic coefficients for the Helfrich membrane in higher dimensions

Using a covariant geometric approach we obtain the effective bending couplings for a 2-dimensional rigid membrane embedded into a $(2+D)$-dimensional Euclidean space. The Hamiltonian for the membrane has three terms: The first one is quadratic in its mean extrinsic curvature. The second one is proportional to its Gaussian curvature, and the last one is proportional to its area. The results we obtain are in agreement with those finding that thermal fluctuations soften the 2-dimensional membrane embedded into a 3-dimensional Euclidean space.Comment: 9 page

Stellar 36,38^{36,38}Ar(n,γ)37,39(n,\gamma)^{37,39}Ar reactions and their effect on light neutron-rich nuclide synthesis

The $^{36}$Ar$(n,\gamma)^{37}$Ar ($t_{1/2}$ = 35 d) and $^{38}$Ar$(n,\gamma)^{39}$Ar (269 y) reactions were studied for the first time with a quasi-Maxwellian ($kT \sim 47$ keV) neutron flux for Maxwellian Average Cross Section (MACS) measurements at stellar energies. Gas samples were irradiated at the high-intensity Soreq applied research accelerator facility-liquid-lithium target neutron source and the $^{37}$Ar/$^{36}$Ar and $^{39}$Ar/$^{38}$Ar ratios in the activated samples were determined by accelerator mass spectrometry at the ATLAS facility (Argonne National Laboratory). The $^{37}$Ar activity was also measured by low-level counting at the University of Bern. Experimental MACS of $^{36}$Ar and $^{38}$Ar, corrected to the standard 30 keV thermal energy, are 1.9(3) mb and 1.3(2) mb, respectively, differing from the theoretical and evaluated values published to date by up to an order of magnitude. The neutron capture cross sections of $^{36,38}$Ar are relevant to the stellar nucleosynthesis of light neutron-rich nuclides; the two experimental values are shown to affect the calculated mass fraction of nuclides in the region A=36-48 during the weak $s$-process. The new production cross sections have implications also for the use of $^{37}$Ar and $^{39}$Ar as environmental tracers in the atmosphere and hydrosphere.Comment: 18 pages + Supp. Mat. (13 pages) Accepted for publication in Phys. Rev. Let

Constraints on Inflation in Einstein-Brans-Dicke Frame

The density perturbation during inflation seeds the large scale structure. We consider both new inflation-type and chaotic inflation-type potentials in the framework of Einstein-Brans-Dicke gravity. The density perturbation gives strong constraints on the parameters in these potentials. For both potentials, the constraints are not much different from those obtained in the original inflationary models by using of Einstein gravity.Comment: 6 pages, Revtex file, typos adde