838 research outputs found
KamLAND Bounds on Solar Antineutrinos and neutrino transition magnetic moments
We investigate the possibility of detecting solar electron antineutrinos with
the KamLAND experiment. These electron antineutrinos are predicted by
spin-flavor oscillations at a significant rate even if this mechanism is not
the leading solution to the SNP. KamLAND is sensitive to antineutrinos
originated from solar B neutrinos. From KamLAND negative results after
145 days of data taking, we obtain model independent limits on the total flux
of solar electron antineutrinos $\Phi({}^8 B)< 1.1-3.5\times 10^4 cm^{-2}\
s^{-1}P<0.15%\mu B< 2.3\times 10^{-21}(\Delta m^2, \tan^2\theta)\mu\lsim 3.9\times 10^{-12} \mu_BB= 50\mu\lsim 9.0\times 10^{-13} \mu_BB= 200\mu\lsim 2.0\times 10^{-13} \mu_BB= 1000$ kG at the same
statistical significance.Comment: 13 pages, 2 figure
Four-year follow-up study in a NF1 Boy with a focal pontine hamartoma
Neurofibromatosis is a collective name for a group of genetic conditions in which benign tumours affect the nervous system. Type 1 is caused by a genetic mutation in the NF1 gene (OMIM 613113) and symptoms can vary dramatically between individuals, even within the same family. Some people have very mild skin changes, whereas others suffer severe medical complications. The condition usually appears in childhood and is diagnosed if two of the following are present: six or more café-au-lait patches larger than 1.5 cm in diameter, axillary or groin freckling, 2 or more Lisch nodules (small pigmented areas in the iris of the eye), 2 or more neurofibromas, optic pathway gliomas, bone dysplasia, and a first-degree family relative with Neurofibromatosis type 1. The pattern of inheritance is autosomal dominant, however, half of all NF1 cases are 'sporadic' and there is no family history. Neurofibromatosis type 1 is an extremely variable condition whose morbidity and mortality is largely dictated by the occurrence of the many complications that may involve any of the body systems. We describe a family affected by NF1 in whom genetic molecular analysis identified the same mutation in the son and father. Routine MRI showed pontine focal lesions in the eight-year-old son, though not in the father. We performed a four years follow-up study and at follow-up pontine hamartoma size remained unchanged in the son, and the father showed still no brain lesions, confirming thus an intra-familial phenotype variability
Development and Implementation of Electronic Applications based on Arduino Platform for a First Basic Course
This paper shows a learning guide about the use of Arduino platform and the different utilities that can be implemented based on this platform for a first basic course.
The paper can be useful as a guide for someone who wants to start in the world of microcontroller programming, with examples to consolidate the knowledge learned. Some students of the School of Industrial Engineering of the University of Malaga (Degree in Industrial Design) approach the study of an engineering career with little knowledge of electronics. This degree contains basic skills on learning electronics and the use of the Arduino platform and its development possibilities can offer students an interesting view of electronics, making better use of classes.
The work is based on both theoretical (to make the components known) and practical (using real assemblies) development to consolidate the knowledge learned. Therefore, once the basic components necessary to carry out various practices have been
explained, the theoretical performance and the programming of Arduino is explained and the various practices that will be set up in the laboratory are presented, as an application of Arduino for different uses.
The main idea of this work is to replace the traditional laboratory practices that require more advanced knowledge in electronics with a set of simple practices carried out in Arduino that allow students to have an approximate idea of basic electronics with little knowledge.
After three years of carrying out this new methodology for this first basic electronic course, the surveys demonstrate a better adaptation of the students to the study of electronics. In addition, the marks obtained have improved considerably and the students have the sensation of learning electronics in a simple and fun way.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Mesozoic geology of Cape Shirreff, Livingston Island, South Shetland Islands, Antarctica
The stratigraphic succession at Cape Shirr e ff has a minimum thickness of 450 m and is mainly composed of lavas and a smaller amount of volcaniclastic breccias. Lavas are subalkaline olivine basalts and basaltic andesites which are locally well - bedded, but in most areas give a homogeneous, sometimes massive aspect to outcrops. Volcaniclastic massive breccias are found in the northern part of Cape Shirreff where they are interstratified with lavas in a few outcrops. Breccias are indurated, heterometric, grain - supported and consist of angular to subangular volcanic rock fragments, 5 to 80 cm in diameter. Petrographic evidence of magma supercooling (skeletal microlites of plagioclase, thermal - shocked phenocrysts of olivine) enables a subaqueous environment for part of the lavas to be deposited and suggests a possible hyaloclastic origin for some interstratified volcanic breccias. The whole succession is cut by subve rtical dykes (10 to 40 cm thick and a few meters to 400 m long), which show variable trends around a NW-SE maximum. These consist of commonly vesiculated basaltic and basaltic andesite porp hyritic rocks, commonly indistinguishable from the lava bodies. Lavas dip variably between 15 and 80Âș, more gently in the south than in the central and northern areas. Although significant variations in dipping attitude could be associated with depositional geometries, the general dipping pattern is clearly consistent with NW-SE oriented large-scale folds showing a gentle dome and basin structure. In the southern area, the NW-SE folds are not so well developed and the structure seems to be consistent with an interference of N-S and E-W oriented folds. The large scale NW-SE folds are consistent with NE-SW shortening. This shortening direction is parallel to the direction of extension deducible from dykes and, hence, folds and dykes are not consistent with the same deformational event
Ferromagnetic coupling of mononuclear Fe centers in a self-assembled metal-organic network on Au(111)
The magnetic state and magnetic coupling of individual atoms in nanoscale
structures relies on a delicate balance between different interactions with the
atomic-scale surrounding. Using scanning tunneling microscopy, we resolve the
self-assembled formation of highly ordered bilayer structures of Fe atoms and
organic linker molecules (T4PT) when deposited on a Au(111) surface. The Fe
atoms are encaged in a three-dimensional coordination motif by three T4PT
molecules in the surface plane and an additional T4PT unit on top. Within this
crystal field, the Fe atoms retain a magnetic ground state with easy-axis
anisotropy, as evidenced by X-ray absorption spectroscopy and X-ray magnetic
circular dichroism. The magnetization curves reveal the existence of
ferromagnetic coupling between the Fe centers
Constraining the neutrino magnetic moment with anti-neutrinos from the Sun
We discuss the impact of different solar neutrino data on the
spin-flavor-precession (SFP) mechanism of neutrino conversion. We find that,
although detailed solar rates and spectra allow the SFP solution as a
sub-leading effect, the recent KamLAND constraint on the solar antineutrino
flux places stronger constraints to this mechanism. Moreover, we show that for
the case of random magnetic fields inside the Sun, one obtains a more stringent
constraint on the neutrino magnetic moment down to the level of \mu_\nu \lsim
few \times 10^{-12}\mu_B, similar to bounds obtained from star cooling.Comment: 4 pages, 3 figures. Final version to appear in Phys. Rev. Let
Effect of nanostructured support on the WGSR activity of Pt/CeO<sub>2</sub> catalysts
Abstract The water gas shift catalytic activity and methane selectivity of Pt/CeO2 catalysts are shown to be strongly dependent on the platinum-ceria interaction. Platinum nanoparticles supported on nanostructured ceria rods present a higher hydrogen yield and lower methane selectivity than its counterpart catalysts supported on ceria nanoparticles or nanocubes, despite the similitude in platinum particle size. Indeed, the constraints of the 1D crystal structure of the ceria nanorods and the selective exposure of the (110) crystal plane are directly related to its superior catalytic activity. Platinum nanoparticles do not only act as active sites for CO adsorption and oxidation but also affect the reducibility of the support.</p
N-Methylation of Amines with Methanol Catalyzed by Iridium(I) Complexes Bearing an N, O-Functionalized NHC Ligand
A set of neutral IrBr(L-2)-(kappa C-(t)BuImCH(2)PyCH(2)OMe)] and cationic Ir(L-2)-(kappa C, N-tBuImCH(2)PyCH(2)OMe)]PF6 (L-2 = cod, (CO)(2)) Ir(I) compounds featuring a flexible lutidine-derived polydentate ligand having NHC and - OMe as donor functions have been evaluated as catalyst precursors for the N-methylation of aniline using methanol both as a reducing agent and a C1 source. The carbonyl complexes are somewhat more active than the related diene compounds with the neutral compound IrBr(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] being the more active. A range of aromatic primary amines, including heterocyclic amines, have been selectively transformed into the corresponding N-methylamino derivatives using this catalyst at a low catalyst loading (0.1 mol %) and substoichiometric amounts of Cs2CO3 (half equiv) as a base, in methanol at 423 K. For aliphatic primary amines, selective N, N-dimethylation was achieved under the same catalytic conditions. The unselective deprotonation of the methylene linkers in IrBr(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] affords two isomeric neutral complexes featuring a coordinated dearomatized pyridine core, which were converted into Ir(OMe)(CO)(2)(kappa C-(t)BuImCH(2)PyCH(2)OMe)] upon addition of methanol. This compound undergoes thermal activation of a C-H bond of the tert-butyl group to give the cyclometalated iridium(I) complex Ir(CO)(2){kappa C-2, C-(-CH2Me2C-ImCH(2)PyCH(2)OMe)}] featuring a bidentate C, C-coordinated NHC ligand. Mechanistic investigations support a borrowing hydrogen mechanism proceeding through iridium(I) intermediates with the methoxo complex as the catalytic active species and the cyclometalated complex as the catalyst resting state. Deuterium labeling experiments have demonstrated that both species are in equilibrium under catalytic conditions, which is consistent with the exhibited catalytic activity of the cyclometalated complex
Intensive longitudinal modelling predicts diurnal activity of salivary alpha-amylase
Salivary alpha-amylase (sAA) activity has been widely used in psychological and medical
research as a surrogate marker of sympathetic nervous system activation, though its utility
remains controversial. The aim of this work was to compare alternative intensive longitudinal
models of sAA data: (a) a traditional model, where sAA is a function of hour (hr) and hr
squared (sAAj,t = f(hr, hr2
), and (b) an autoregressive model, where values of sAA are a
function of previous values (sAAj,t = f(sAA j,t-1, sAA j,t-2, . . ., sAA j,t-p). Nineteen normal subjects (9 males and 10 females) participated in the experiments and measurements were performed every hr between 9:00 and 21:00 hr. Thus, a total of 13 measurements were
obtained per participant. The Napierian logarithm of the enzymatic activity of sAA was analysed. Data showed that a second-order autoregressive (AR(2)) model was more parsimonious and fitted better than the traditional multilevel quadratic model. Therefore, sAA follows a
process whereby, to forecast its value at any given time, sAA values one and two hr prior to
that time (sAA j,t = f(SAAj,t-1, SAAj,t-2) are most predictive, thus indicating that sAA has its
own inertia, with a âmemoryâ of the two previous hr. These novel findings highlight the relevance of intensive longitudinal models in physiological data analysis and have considerable
implications for physiological and biobehavioural research involving sAA measurements
and other stress-related biomarkers
Early (Ti, Zr)-late (Rh, Ir) heteronuclear complexes with bridging sulphido ligands
[EN]: We report in this account on the controlled synthesis of novel d0-d8 early-late heteropolynuclear diolefin and carbonyl clusters. The synthetic approach was based on additive-deprotonation reactions involving the titanium and zirconium bis-hydrosulphido complexes of formula [Cp2Ti(SH)2] and [Cptt 2Zr(SH)2] and appropriate rhodium and iridium diolefin and carbonyl compounds. The significant differences between the resulting early-late complexes and their structures coming from the titanium or zirconium metalloligand precursors are highlighted. The catalytic activity of some representative titanium-rhodium and zirconium-rhodium compounds towards alkene hydroformylation was explored. Interestingly, the heterotetranuclear 'CpTi(ÎŒ3-S)3Rh3' structure was maintained as such under mild conditions.[FR]: Nous rapportons dans cet article la prĂ©paration contrĂŽlĂ©e de nouveaux clusters hĂ©tĂ©ropolynuclĂ©aires early-late d0âd8 portant les ligands olĂ©fine et carbonyle. La rĂ©action de dĂ©protonationâaddition a Ă©tĂ© la mĂ©thode de synthĂšse utilisĂ©e et implique la condensation de complexes bis-hydrogĂ©nosulfure du titane et du zirconium, de formule [Cp2Ti(SH)2] et [Cptt2Zr(SH)2], sur les composĂ©s adĂ©quats du rhodium et de lâiridium portant les ligands olĂ©fine et carbonyle. Les diffĂ©rences significatives de structure entre les complexes early-late ainsi prĂ©parĂ©s, dues Ă la nature du mĂ©talloligand prĂ©curseur du titane ou du zirconium employĂ©, sont mises en Ă©vidence. LâactivitĂ© catalytique de quelques composĂ©s reprĂ©sentatifs titaneârhodium et zirconiumârhodium dans lâhydroformylation dâalcĂšnes a Ă©tĂ© mesurĂ©e. Il convient de noter que la structure hĂ©tĂ©rotĂ©tranuclĂ©aire « CpTi(ÎŒ3-S)3Rh3 » est maintenue comme telle sous des conditions douces de rĂ©action.Peer Reviewe
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