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Despite their crystalline nature, thermoelectric clathrates exhibit a strongly reduced lattice thermal conductivity. While the reason for this unexpected behavior is known to lie in the peculiarities of the complex crystal structure and the interplay of the underlying guest-host framework, their respective roles are still not fully disentangled and understood. Our ab initio study of the most simple type-I clathrate phase, the binary compound ${\mathrm{Ba}}_{8}{\mathrm{Si}}_{46}$ and its derivatives ${\mathrm{Ba}}_{8\ensuremath{-}x}{\mathrm{Si}}_{46}$ seeks to identify these mechanisms and provides insight into their origin. Indeed, the strongly decreased lattice thermal conductivity in thermoelectric clathrates is a consequence of a reduction of the acoustic phonon bandwidth, a lowering of the acoustic phonon group velocities, and the amplification of three-phonon-scattering processes. While the complexity of the crystal structure is demonstrated not to be the leading factor, the reasons are manifold. A modified Si-Si interaction causes a first decrease of the sound velocity, whereas the presence of flat Ba modes results in an additional lowering. These modes correspond to confined Bloch states that are localized on the Ba atoms and significantly increase the scattering phase space and, together with an increased anharmonicity of the interatomic interactions, strongly affect the phonon lifetimes.

This is the author final draft version of article https://doi.org/10.1103/PhysRevLett.120.135504 As ultrastable metallic glasses (UMGs) are promising candidates to solve the stability issues of conventional metallic glasses, their study is of exceptional interest. By means of x -ray photon correlation spectroscopy, we have investigated the stability of UMGs at the atomic level. We find a clear signature of ultrastability at the atomic level that results in slower relaxation dynamics of UMGs with respect to conventional (rapidly quenched) metallic glasses, and in a peculiar acceleration of the dynamics by near T g annealing. This surprising phenomenon, called here anti-aging, can be understood in the framework of the potential energy landscape. For all samples, the structural relaxation process can be described with a highly compressed shape of the density fluctuations, unaffected by thermal treatments and regardless of the ultrastability of the glass.

In this work we present a molecular dynamics investigation of thermal transport in a silica-gallium nitride nanocomposite. A surprising enhancement of the thermal conductivity for crystalline volume fractions larger than 5% is found, which cannot be predicted by an effective medium approach, not even including percolation effects, the model systematically leading to an underestimation of the effective thermal conductivity. The behavior can instead be reproduced if an effective volume fraction twice larger than the real one is assumed, which translates into a percolation effect surprisingly stronger than the usual one. Such a scenario can be understood in terms of a phonon tunneling between inclusions, enhanced by the iso-orientation of all particles. Indeed, if a misorientation is introduced, the thermal conductivity strongly decreases. We also show that a percolating nanocomposite clearly stands in a different position than other nanocomposites, where thermal transport is dominated by the interface scattering and where parameters such as the interface density play a major role, differently from our case.

M Guida,1 D Maffucci,1 G Iannuzzi,1 M Giordano,1 G Luciano,1 L Di Benedetto,2 R Cantarella,3 A Rescigno,3 L Giugliano1 1Università degli studi di Salerno – Dipartimento di Medicina, Chirurgia e Odontoiatria “Scuola Medica Salernitana”, Salerno, Italy; 2Università degli studi di Roma “La Sapienza” – Dipartimento di Scienze Medico-Chirurgiche e di Medicina Traslazionale – Facoltà di Medicina e Psicologia Azienda Ospedaliera Sant’ Andrea, Rome, Italy; 3Azienda Ospedaliera Universitaria San Giovanni di Dio e Ruggi D’Aragona, Salerno, Italy Objective: This paper reports on a rare case of pregnancy after uterine artery embolization (UAE) for uterine arteriovenous malformation (AVM). Debate exists about persistence of fertility in women after UAE. Adverse effects of this technique can modify both uterine echostructure, inducing necrosis and infarction, endometrial atrophy and uterine artery rupture, and ovarian reserve, causing persistent amenorrhea. Ovarian reserve appears to be affected by UAE in premenopausal women. However, younger ovaries (according to biological ovarian age) exhibit a greater capacity for recovery after ovarian damage. Therefore, larger studies are needed for more conclusive results. Case report: A 28-year-old woman was admitted to our department due to life-threatening uterine bleeding, resulting in tachycardia, pallor, and sweating. The patient came with a history of two spontaneous miscarriages. After sonography and computed tomography, AVMs were identified at uterine fundus and anterior wall. Conclusion: The pathogenesis of infertility after UAE is not yet known. The peculiarity of this case was that, only few months later, the patient became pregnant and gave birth to a live fetus at 37 weeks with cesarean delivery. Keywords: uterine artery embolization, fertility, uterine arteriovenous malformation, pregnancy, angiography

In amorphous solids, a non-negligible part of thermal conductivity results from phonon scattering on the structural disorder. The conversion of acoustic energy into thermal energy is often measured by the Dynamical Structure Factor (DSF) thanks to inelastic neutron or X-Ray scattering. The DSF is used to quantify the dispersion relation of phonons, together with their damping. However, the connection of the dynamical structure factor with dynamical attenuation of wave packets in glasses is still a matter of debate. We focus here on the analysis of wave packets propagation in numerical models of amorphous silicon. We show that the DHO fits (Damped Harmonic Oscillator model) of the dynamical structure factors give a good estimate of the wave packets mean-free path, only below the Ioffe-Regel limit. Above the Ioffe-Regel limit and below the mobility edge, a pure diffusive regime without a definite mean free path is observed. The high-frequency mobility edge is characteristic of a transition to localized vibrations. Below the Ioffe-Regel criterion, a mixed regime is evidenced at intermediate frequencies, with a coexistence of propagative and diffusive wave fronts. The transition between these different regimes is analyzed in details and reveals a complex dynamics for energy transportation, thus raising the question of the correct modeling of thermal transport in amorphous materials., Comment: 9 pages, 7 figures

In a previous paper based on dark matter only simulations we show that, in the approximation of an analytic and static potential describing the strongly triaxial and cuspy shape of Milky Way-sized haloes, diffusion due to chaotic mixing in the neighbourhood of the Sun does not efficiently erase phase space signatures of past accretion events. In this second paper we further explore the effect of chaotic mixing using multicomponent Galactic potential models and solar neighbourhood-like volumes extracted from fully cosmological hydrodynamic simulations, thus naturally accounting for the gravitational potential associated with baryonic components, such as the bulge and disc. Despite the strong change in the global Galactic potentials with respect to those obtained in dark matter only simulations, our results confirm that a large fraction of halo particles evolving on chaotic orbits exhibit their chaotic behaviour after periods of time significantly larger than a Hubble time. In addition, significant diffusion in phase space is not observed on those particles that do exhibit chaotic behaviour within a Hubble time., 17 pages, 10 figures, 3 tables. Accepted for publication in MNRAS

An observation of neutrinoless double beta ([Formula: see text]) decay would allow to shed light onto the nature of neutrinos. Gerda (GERmanium Detector Array) aims to discover this process in a background-free search using [Formula: see text]Ge. The experiment is located at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. Bare, isotopically enriched, high purity germanium detectors are operated in liquid argon. Gerda follows a staged approach. In Phase II 35.6 kg of enriched germanium detectors are operated since December 2015. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allows to reduce the background index to the intended level of [Formula: see text] cts/(keV⋅kg⋅yr). No evidence for the [Formula: see text] decay has been found in 23.2 kg⋅yr of Phase II data, and together with data from Phase I the up-to-date most stringent half-life limit for this process in [Formula: see text]Ge has been established, at a median sensitivity of 5.8⋅10[Formula: see text][Formula: see text]yr the 90[Formula: see text]% C.L. lower limit is 8.0⋅10[Formula: see text][Formula: see text]yr.

Energy dependence and an increasing concern with climate change are currently major challenges faced by European Union (EU) countries. Implementing Energy Efficiency (EE) measures and Renewable Energy Sources (RES) are privileged approaches to contribute to reduce both EU energy consumption and climate vulnerability while contributing to implement the Sustainable Development Goals 7 - Affordable and clean energy and 11 - Make cities and human settlements inclusive, safe, resilient and sustainable. However, the implementation of EE measures and RES options in Municipal Public Buildings (MPBs) is hampered not only by a general lack of financial resources, but also by an insufficient knowledge of public authorities on the buildings' features and consumption, as well as on the potentially most effective options to improve their energy performance. One of the challenges for making the public building sector more sustainable is to be able to develop solutions adapted to various regional contexts, level of urbanization of the area, availability of energy resources and types of buildings. Moreover, publics buildings with different usage, (i.e. swimming pools, health centres, sports centre, schools, office buildings) have associated different energy services (e.g. space heating and cooling, water heating, lighting, other electric equipment) and consumption profiles. Public authorities have to manage varied building stocks and thus need to enhance their institutional capacity in the field of EE and use of RES to contribute to the Energy Performance of Buildings and the Energy Efficiency EU Directives. The PrioritEE project, funded by the Interreg MED programme, aims at strengthening the capacities of public administrations in selecting and implementing efficient and cost-effective energy solutions in their public building stock. This work describes the Excel based Decision Support Tool (DST) under development for the ranking and selection of measures for improving EE and increasing RES adoption in MPBs. The tool is being co-developed, validated and tested by local public authorities and professional institutions from five country pilots with the aim of reducing energy consumption and prioritize EE investments. The pilots are located in regions with significant climatic differences: Potenza, Italy (HDD=1762); Leziria do Tejo, Portugal (HDD=893); Teruel, Spain (HDD=1725); West Macedonia, Greece (2508) and Karlovac, Croatia (2364); allowing to test the DST in different European contexts. A comprehensive set of key performance indicators is an integral part of the DST and will be used to compare different scenarios of interventions and monitor energy consumption, assessing the effects of the proposed strategies. The DST components, namely its main features (e.g. analytical database), building typologies and energy services addressed, as well as the results obtained to over 100 MPBs within the five pilot regions will be discussed as a ranking per investment (total, per user, per m2, payback period), and energy savings (total, per user, per m2), among others. Moreover, a focus on how results are being used by local public authorities will be presented, evaluating the DST transferability to other countries, cities and regions.

In this article, we consider the quasi-linear stochastic wave and heat equations on the real line and with an additive Gaussian noise which is white in time and behaves in space like a fractional Brownian motion with Hurst index $H\in (0,1)$. The drift term is assumed to be globally Lipschitz. We prove that the solution of each of the above equations is continuous in terms of the index $H$, with respect to the convergence in law in the space of continuous functions., Comment: 25 pages

International audience; In the last years new composite materials made of a metallic glass matrix with embedded nanocrystals have arisen as a promising alternative to the metallic glasses, due to their higher hardness. Although the effects of a partial nano-crystallization onto mechanical and magnetic properties have been widely investigated, nothing is known about thermal transport properties, interesting for recently proposed novel applications. Here we investigate how thermal transport is modified in presence of nanocrystalline inclusions in a Zr-based bulk metallic glass. By means of electric measurements and inelastic x ray scattering we are able to disentangle the effects of a partial nanocrystallization onto the two different contributions to heat transport, the electronic and the vibrational one. We show that no enhanced electrons or phonons scattering from the interfaces is observed, while the presence of crystalline nanoinclusions leads to an increase of both contributions, via an increased electric conductivity and transverse acoustic speed of sound. Surprisingly, while a gradual modification of the electric conductivity with the crystalline fraction is observed, even a low crystalline fraction is sufficient to modify elastic and vibrational properties. Our results indicate that low crystallinity composites are indeed promising alternative to both amorphous and crystalline alloys, thanks to their unique combination of high ductility, polycrystal-like vibrational properties and amorphous-like electric transport. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Astrometric microlensing will offer in the next future a new channel for investigating the nature of both lenses and sources involved in a gravitational microlensing event. The effect, corresponding to the shift of the position of the multiple image centroid with respect to the source star location, is expected to occurr on scales from micro-arcoseconds to milli-arcoseconds depending on the characteristics of the lens-source system. Here, we consider different classes of events (single/binary lens acting on a single/binary source) also accounting for additional effects including the finite source size, the blending and orbital motion. This is particularly important in the era of Gaia observations which is making possible astrometric measurements with unprecedent quality., On IJMP D, 15 pages, 6 Figures

C4 grasses are favoured as forage crops in warm, humid climates. The use of C4 grasses in pastures is expected to increase because the tropical belt is widening due to global climate change. While the forage quality of Paspalum dilatatum (dallisgrass) is higher than that of other C4 forage grass species, digestibility of warm-season grasses is, in general, poor compared with most temperate grasses. The presence of thick-walled parenchyma bundle-sheath cells around the vascular bundles found in the C4 forage grasses are associated with the deposition of lignin polymers in cell walls. High lignin content correlates negatively with digestibility, which is further reduced by a high ratio of syringyl (S) to guaiacyl (G) lignin subunits. Cinnamoyl-CoA reductase (CCR) catalyses the conversion of cinnamoyl CoA to cinnemaldehyde in the monolignol biosynthetic pathway and is considered to be the first step in the lignin-specific branch of the phenylpropanoid pathway. We have isolated three putative CCR1 cDNAs from P. dilatatum and demonstrated that their spatio-temporal expression pattern correlates with the developmental profile of lignin deposition. Further, transgenic P. dilatatum plants were produced in which a sense-suppression gene cassette, delivered free of vector backbone and integrated separately to the selectable marker, reduced CCR1 transcript levels. This resulted in the reduction of lignin, largely attributable to a decrease in G lignin. Electronic supplementary material The online version of this article (doi:10.1007/s11248-014-9784-1) contains supplementary material, which is available to authorized users.

Gravitational microlensing offers a powerful method with which to probe a variety of binary-lens systems, as the binarity of the lens introduces deviations from the typical (single-lens) Paczy\'nski behaviour in the event light curves. Generally, a static binary lens is considered to fit the observed light curve and, when the orbital motion is taken into account, an oversimplified model is usually employed. In this paper, we treat the binary-lens motion in a realistic way and focus on simulated events that are fitted well by a Paczy\'nski curve. We show that an accurate timing analysis of the residuals (calculated with respect to the best-fitting Paczy\'nski model) is usually sufficient to infer the orbital period of the binary lens. It goes without saying that the independently estimated period may be used to further constrain the orbital parameters obtained by the best-fitting procedure, which often gives degenerate solutions. We also present a preliminary analysis of the event OGLE-2011-BLG-1127 / MOA-2011-BLG-322, which has been recognized to be the result of a binary lens. The period analysis results in a periodicity of \simeq 12 days, which confirms the oscillation of the observed data around the best-fitting model. The estimated periodicity is probably associated with an intrinsic variability of the source star, and therefore there is an opportunity to use this technique to investigate either the intrinsic variability of the source or the effects induced by the binary-lens orbital motion., Comment: In press on MNRAS, 2014. 8 pages, 4 figures. On-line material available on the Journal web-page

In addition to playing a key role in the response to environmental changes, cell walls are also considered as a valuable feedstock for cellulosic ethanol. Here we explored the effects of the stress-response hormones, salicylic acid and methyl jasmonate, on cell wall biosynthesis and biomass digestibility in Brachypodium distachyon, a species recently considered as a suitable model for biomass conversion. We found that in response to salicylic acid or methyl jasmonate treatment, plant growth was reduced coupled with significant changes in cell wall composition. Cellulose content increased in response to methyl jasmonate whereas a reduction in lignin content was found after salicylic acid application. Moreover, hemicellulose composition was altered and increases in caffeic acid, ferulic acid and p-coumaric acid content were detected in response to both treatments. The hormonal profile and the expression pattern of genes involved in cell wall biosynthesis were also modified. Biomass digestibility was reduced in leaf tissue after salicylic acid treatment and was negatively correlated with ferulic acid and p-coumaric acid content. The results obtained here aid in our understanding of cell wall dynamics in response to stress and will enable the development of new strategies to improve cell wall digestibility in bioenergy feedstock.

IntroductionNegative symptoms are a core feature of schizophrenia but their pathophysiology remains elusive. They cluster in a motivation-related domain, including apathy, anhedonia, asociality and in an expression-related domain, including alogia and blunted affect.AimOur aim was to investigate the different neurobiological underpinnings of the two domains using the brain electrical microstates (MS), which reflect global patterns of functional connectivity with high temporal resolution.MethodWe recorded multichannel resting EEGs in 142 schizophrenia patients (SCZ) and in 64 healthy controls (HC), recruited to the Italian network for research on psychoses study. Four microstates (MS) classes were computed from resting EEG data using the K-Mean clustering algorithm. Pearson's coefficient was used to investigate correlations of microstates measures with negative symptom domains, assessed by the Brief Negative Symptoms Scale (BNSS).ResultsSCZ, in comparison to HC, showed increased contribution and duration of MS-C. Only the avolition domain of BNSS correlated with the contribution and occurrence of MS-A. Within the same domain, anticipatory anhedonia, apathy and asociality, but not consummatory anhedonia, were positively correlated with contribution and occurrence of microstate A. Asociality was also negatively correlated with contribution and occurrence of MS-D.ConclusionOur findings support different neurobiological underpinnings of the negative symptom domains, avolition and expressive deficit. Furthermore, our results lend support to the hypothesis that only anticipatory anhedonia is linked to the avolition domain of the negative symptoms. Mixed results in the literature concerning the presence of MS-A and D abnormalities in schizophrenia might be related to the syndrome heterogeneity.Disclosure of interestThe authors have not supplied their declaration of competing interest.

IntroductionThe effects of chronic antipsychotic administration on the human brain are debated. In particular, first-generation (FGAs) and second-generation antipsychotics (SGAs) seem to have different impacts on brain function and structure in subjects with schizophrenia. Few studies have investigated the effect of chronic administration of FGAs and SGAs on indices of brain function, such as event-related potentials (ERP) or neuropsychological performance.ObjectivesWithin the Italian Network for Research on Psychoses study, subjects stabilized on FGAs or SGAs were compared on P300, an ERP component, thought to reflect attention, working memory and context integration and on neurocognitive indices.MethodsERPs were recorded in 110 chronic, stabilized patients with Schizophrenia (28 used FGAs) during a standard auditory oddball task. P300 latency and amplitude were assessed at Pz channel. MATRICS Consensus Cognitive Battery (MCCB) was used for cognitive assessment.ResultsCompared with the SGAs group, patients on FGAs showed significant increased P300 latency (P = 0.003; Cohen's d = 0.67) and significant decreased P300 amplitudes (P = 0.023; Cohen's d = 0.38). The two groups did not differ on psychopathology and MCCB scores. Multiple linear regressions revealed that “FGAs vs. SGAs” (β = 0.298, P = 0.002) and MCCB neurocognitive composite T-score (β = –0.273, P = 0.004) were independent predictors of P300 latency, whereas only age (β = –0.220, P = 0.027) was an independent predictor of P300 amplitude.ConclusionsFGAs seem to affect the functional brain activity more than SGAs, particularly slowing cortical processing. Our results suggest that discrepant findings concerning P300 latency in schizophrenia might be related to the type of antipsychotic treatment used. Longitudinal studies are needed to further address this issue.Disclosure of interestThe authors have not supplied their declaration of competing interest.

The sbv IMPROVER published a call for participation in the SysTox Computation Challenge [1]. Participants were asked to develop models to classify subjects as smokers versus non-current smokers, and then former smokers versus never smokers, based on the information from whole blood gene expression data from human, or human and rodent. The first condition of the challenge was that proposed models had to be inductive, that is, once the model had been developed based on training data, classification on each test sample could be carried out only with the previously developed model, without retraining. Inductive models are opposite to transductive models in which training and test set processed together and used to retrain models prior to classification prediction. Another rule of the challenge was that classification models should rely only on a small subset of genes (less than 40) from whole blood gene expression. The sbv IMPROVER SysTox Computation Challenge [1] asked participants to develop inductive models to classify subjects as smokers vs non-current smokers, and then former smokers vs never smokers, based on the information from a small subset of genes (

Timing analysis is a powerful tool used to determine periodic features of physical phenomena. Here we review two applications of timing analysis to gravitational microlensing events. The first one, in particular cases, allows the estimation of the orbital period of binary lenses, which in turn enables the breaking of degeneracies. The second one is a method to measure the rotation period of the lensed star by observing signatures due to stellar spots on its surface., 11 pages, 4 figures. To be published in International Journal of Modern Physics D (IJMPD)

Common control methods for free-floating robots assume zero initial linear and angular momenta, for which a reduced joint dynamics equivalent to that of a fixed-base robot can be obtained. On the other hand, a disturbance is induced in the system dynamics when the linear or angular momenta are not zero, leading to a deviation of the end effector. In this work the dynamics of the free-floating robot in presence of momentum is analyzed and a torque feedback control is proposed. An operational space formulation is considered to identify the disturbing Coriolis/centrifugal forces and to cancel them by feedback. A stability proof for the proposed controller is developed using a time-varying approach. The effectiveness of the control is shown in simulation for a seven degrees-of-freedom arm connected to a floating-base under the effect of linear and angular momenta considering model parameters uncertainties.

Drought is the main abiotic stress constraining sugarcane production. However, our limited understanding of the molecular mechanisms involved in the drought stress responses of sugarcane impairs the development of new technologies to increase sugarcane drought tolerance. Here, an integrated approach was performed to reveal the molecular and physiological changes in two closely related sugarcane cultivars, including the most extensively planted cultivar in Brazil (cv. RB867515), in response to moderate (−0.5 MPa) and severe (−1 MPa) drought stress at the transcriptional, translational, and posttranslational levels. The results show common and cultivar exclusive changes in specific genes related to photosynthesis, carbohydrate, amino acid, and phytohormone metabolism. The novel phosphoproteomics and redox proteomic analysis revealed the importance of posttranslational regulation mechanisms during sugarcane drought stress. The shift to soluble sugar, secondary metabolite production, and activation of ROS eliminating processes in response to drought tolerance were mechanisms exclusive to cv. RB867515, helping to explain the better performance and higher production of this cultivar under these stress conditions.

High-throughput DFT calculations are used to predict the thermodynamic stability of ternary type I Si clathrates.

Developing fundamental tools and insight into biomaterial designs for predictive functional outcomes remains critical for the field. Silk is a promising candidate as a biomaterial for tissue engineering scaffolds, particularly where high mechanical loads or slow rates of degradation are desirable. Although bioinspired synthetic spider silks are feasible biomaterials for this purpose, insight into how well the degradation rate can be programmed by fine tuning the sequence remains to be determined. Here we integrated experimental approaches and computational modelling to investigate the degradation of two bioengineered spider silk block copolymers, H(AB)

It has been shown that the presence of bicarbonate ions and chloride is necessary to produce stress corrosion cracking (SCC) in alloy 22 at anodic applied potentials. It has been suggested that the susceptibility to SCC could be related to the occurrence of an anodic peak in the polarization curves below the transpassive rangeThe aim of this work is to study the anodic behavior of alloy 22 and other nickel alloys in different media containing bicarbonate ions and chloride in various concentrations and temperatures to determine if there is a correlation between the presence of the anodic peak and the occurrence of SCC; and to determine which element in the alloy maybe be responsible for the cracking. The studied alloys included alloy 22, Ni-200, alloy 800 and alloy 600. Results show that in general the potential and the peak current increased with temperature and chloride concentration in the solution. For the alloys with the smaller alloying content the peak potential decreased to the point of disappearing. There was no dependence of the current peak with the amount of alloying

We show that a second order differential equation, when represented as a vector field on TQ or T ∗ Q , may admit alternative Lagrangian and Hamiltonian descriptions. When Q is in addition a Lie group, the bundle may be a double Lie group; in this case we find group-valued constants of motion.

Bioreactor cultures of Escherichia coli recombinants carrying phaBAC and phaP of Azotobacter sp. FA8 grown on glycerol under low-agitation conditions accumulated more poly(3-hydroxybutyrate) (PHB) and ethanol than at high agitation, while in glucose cultures, low agitation led to a decrease in PHB formation. Cells produced smaller amounts of acids from glycerol than from glucose. Glycerol batch cultures stirred at 125 rpm accumulated, in 24 h, 30.1% (wt/wt) PHB with a relative molecular mass of 1.9 MDa, close to that of PHB obtained using glucose. Copyright © 2010, American Society for Microbiology. All Rights Reserved. Fil: de Almeida, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina Fil: Giordano, Andrea Mariana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Nikel, Pablo Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Pettinari, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

We report the oxygen K-edge spectra of ices Ih, VI, VII, and VIII measured with X-ray Raman scattering. The pre-edge and main-edge contributions increase strongly with density, even though the hydrogen bond arrangements are very similar in these phases. While the near-edge spectral features in water and ice have often been linked to hydrogen bonding, we show that the spectral changes in the phases studied here can be quantitatively related to structural changes in the second coordination shell. Density-functional theory calculations reproduce the experimental results and support the conclusion. Our results suggest that non-hydrogen-bonded neighbors can have a significant effect also in the liquid water spectrum. We discuss the implications of the results for the actively debated interpretation of the liquid water spectrum in terms of local structure.

On the macroscopic scale, the wavelengths of sound waves in glasses are large enough that the details of the disordered microscopic structure are usually irrelevant, and the medium can be considered as a continuum. On decreasing the wavelength this approximation must of course fail at one point. We show here that this takes place unexpectedly on the mesoscopic scale characteristic of the medium range order of glasses, where it still works well for the corresponding crystalline phases. Specifically, we find that the acoustic excitations with nanometric wavelengths show the clear signature of being strongly scattered, indicating the existence of a cross-over between well-defined acoustic modes for larger wavelengths and ill-defined ones for smaller wavelengths. This cross-over region is accompanied by a softening of the sound velocity that quantitatively accounts for the excess observed in the vibrational density of states of glasses over the Debye level at energies of a few milli-electronvolts. These findings thus highlight the acoustic contribution to the well-known universal low-temperature anomalies found in the specific heat of glasses.

We discuss the non perturbative approach to the problem of high-energy hadron-hadron (dipole-dipole) scattering at low momentum transfer by means of numerical simulations in Lattice Gauge Theory., 4 pages, 5 figures, LaTeX with espcrc2.sty (v. 2.7). To appear in the proceedings of the 14th International QCD Conference (QCD 08), Montpellier, France, 7-12 July 2008

PurposeThe purpose of this paper is to remind sponsors and managers of hedge funds and private funds (including private equity and venture capital funds) of certain “best practices” that they should consider.Design/methodology/approachThe paper offers considerations concerning: preparation and review of written compliance and procedures documents; updating Form ADV; other regulatory filings including blue sky filings, Form 13F, Schedule 13D/13G, Forms 3, 4, and 5, and other forms; audited financial statements; Schedule K‐1; offering document updates; fee deferral arrangements; CFTC requirements; liability insurance; employee training; and other annual requirements including privacy policies and new issues.FindingsAmid recent rapid growth in hedge funds and private equity funds and volatility in the financial markets, it is more important than ever to ensure that regulatory filings and compliance policies and procedures are properly documented and followed.Originality/valueThis paper provides a brief, useful checklist from experienced securities lawyers, but a comprehensive guide or legal advice concerning any specific situation.

We model chaotic diffusion in a symplectic four-dimensional (4D) map by using the result of a theorem that was developed for stochastically perturbed integrable Hamiltonian systems. We explicitly consider a map defined by a free rotator (FR) coupled to a standard map (SM). We focus on the diffusion process in the action I of the FR, obtaining a seminumerical method to compute the diffusion coefficient. We study two cases corresponding to a thick and a thin chaotic layer in the SM phase space and we discuss a related conjecture stated in the past. In the first case, the numerically computed probability density function for the action I is well interpolated by the solution of a Fokker-Planck (FP) equation, whereas it presents a nonconstant time shift with respect to the concomitant FP solution in the second case suggesting the presence of an anomalous diffusion time scale. The explicit calculation of a diffusion coefficient for a 4D symplectic map can be useful to understand the slow diffusion observed in celestial mechanics and accelerator physics., Instituto de Astrofísica de La Plata

Background. Left ventricular hypertrophy (LVH) is the main compensatory mechanism to pressure overload in patients with aortic stenosis (AS). The increased left ventricular mass, related diastolic and coronary microcirculation dysfunctions (CMD) contribute to diastolic heart failure, clinical angina, arrhythmias and sudden death. Aortic valve replacement (AVR) leads to hemodynamic and metabolic improvement and to favorable changes in myocardial perfusion contributing to prolongation of survival. The aim of this study was to evaluate whether mechanical or porcine aortic prostheses differently impact diastolic dysfunction (DD) and CMD recovery after AVR for pure AS. Methods. Fifty patients having undergone AVR for pure AS with Medtronic Mosaic Ultra (MMU) bioprosthesis 21 mm (n=25) or St. Jude Medical Regent (SJR) mechanical valve 19 mm (n=25) were evaluated preoperatively and 12 months postoperatively comparing the hemodynamic behavior and the coronary flow by echocardiography and adenosine and rest cardiac magnetic resonance-myocardial perfusion imaging (CMR-MPI). Results. At 12 month follow-up significant differences in E/A ratio and isovolumetric relaxation time between the two groups were found. The E/A ratio decreased from 1.3 ± 0.2 to 0.8 ± 0.2 in the MMU group and from 1.1 ± 0.1 to 0.9 ± 0.1 in the SJR group (p

We use computational high-throughput techniques to study the thermodynamic stability of ternary type I Si clathrates. Two strategies to stabilize the structures are investigated: through endohedral doping of the 2a and 6d Wyckoff positions (located at the center of the small and large cages, respectively) and by substituting the Si 6c positions. Our results agree with the overwhelming majority of experimental results and predict a series of unknown clathrate phases. Many of the stable phases can be explained by the simple Zintl–Klemm rule, but some are unexpected. We then successfully synthesize one of the latter compounds, a new type I silicon clathrate containing Ba (inside the cages) and Be (in the 6c position). These results prove the predictive power and reliability of our strategy and motivate the use of high-throughput screening of materials properties for the accelerated discovery of new clathrate phases.

The main objectives of the KM3NeT Collaboration are (i) the discovery and subsequent observation of high-energy neutrino sources in the Universe and (ii) the determination of the mass hierarchy of neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: (1) the high-energy astrophysical neutrino signal reported by IceCube and (2) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure consisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the synergistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon (France), Capo Passero (Sicily, Italy) and Pylos (Peloponnese, Greece). The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three-dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely configured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and complementary field of view, including the galactic plane. One building block will be densely configured to precisely measure atmospheric neutrino oscillations.

After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge) of supermassive black holes in the center of ours and nearby galaxies., Comment: 22 pages, 10 figures. Invited review for Universe

A prototype detection unit of the KM3NeT deep-sea neutrino telescope has been installed at 3500m depth 80 km offshore the Italian coast. KM3NeT in its final configuration will contain several hundreds of detection units. Each detection unit is a mechanical structure anchored to the sea floor, held vertical by a submerged buoy and supporting optical modules for the detection of Cherenkov light emitted by charged secondary particles emerging from neutrino interactions. This prototype string implements three optical modules with 31 photomultiplier tubes each. These optical modules were developed by the KM3NeT Collaboration to enhance the detection capability of neutrino interactions. The prototype detection unit was operated since its deployment in May 2014 until its decommissioning in July 2015. Reconstruction of the particle trajectories from the data requires a nanosecond accuracy in the time calibration. A procedure for relative time calibration of the photomultiplier tubes contained in each optical module is described. This procedure is based on the measured coincidences produced in the sea by the $$^{40}$$40K background light and can easily be expanded to a detector with several thousands of optical modules. The time offsets between the different optical modules are obtained using LED nanobeacons mounted inside them. A set of data corresponding to 600 h of livetime was analysed. The results show good agreement with Monte Carlo simulations of the expected optical background and the signal from atmospheric muons. An almost background-free sample of muons was selected by filtering the time correlated signals on all the three optical modules. The zenith angle of the selected muons was reconstructed with a precision of about 3$$^\circ $$∘. © 2016, The Author(s).

Recent theoretical models for the vibrations in glasses assume that the complex elastic modulus depends on frequency but not on the wave vector, $q$. This assumption translates in a simple $q$ dependence of the dynamic structure factor, which can be experimentally tested. Following the suggestion of a recent paper [U. Buchenau, Phys. Rev. E 90, 062319 (2014)], we present here a new analysis, performed in $q$ space, of inelastic x-ray scattering data of supercooled silica. The outcome of the analysis is compared to the more common approach in the frequency domain and indicates that the mentioned theoretical assumption is consistent with the data only below the boson peak frequency. At higher frequencies it gives rise to a breakdown of the classical second moment sum rule. This violation arises from the underlying assumption of the presence of a single excitation in the spectra. A comparison with the vibrational dynamics of $\ensuremath{\alpha}$-cristobalite suggests, on the contrary, that in the terahertz frequency domain the inelastic spectrum of the glass gains contributions from both acousticlike and opticlike modes. A microscopic theory of the vibrations in glasses cannot neglect the medium range order in their structure, which gives rise to dispersion curves within a pseudo-Brillouin zone.

In gravitational microlensing, binary systems may act as lenses or sources. Identifying lens binarity is generally easy especially in events characterized by caustic crossing since the resulting light curve exhibits strong deviations from smooth single-lensing light curve. On the contrary, light curves with minor deviations from a Paczy\'nski behaviour do not allow one to identify the source binarity. A consequence of the gravitational microlensing is the shift of the position of the multiple image centroid with respect to the source star location - the so called astrometric microlensing signal. When the astrometric signal is considered, the presence of a binary source manifests with a path that largely differs from that expected for single-source events. Here, we investigate the astrometric signatures of binary sources taking into account their orbital motion and the parallax effect due to the Earth motion, which turn out not to be negligible in most cases. We also show that considering the above-mentioned effects is important in the analysis of astrometric data in order to correctly estimate the lens-event parameters., Comment: Published on ApJ, 2016, 823, 120