Statistical similarity between the compression of a porous material and earthquakes

It has been long stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallelisms between these so separate phenomena. We study the Acoustic Emission events produced during the compression of Vycor (SiO2). The Gutenberg-Richter law, the modified Omori's law, and the law of aftershock productivity are found to hold for a minimum of 5 decades, are independent of the compression rate, and keep stationary for all the duration of the experiments. The waiting-time distribution fulfills a unified scaling law with a power-law exponent close to 2.45 for long times, which is explained in terms of the temporal variations of the activity rate.Comment: 4 pages and a bit more, 4 figure

Scale-invariant avalanche dynamics in the temperature-driven martensitic transition of a Cu-Al-Be single crystal

We have combined high sensitivity, extra-low differential temperature scanning rate calorimetry, and acoustic emission (AE) measurements to study avalanches during the cubic ↔ 18R martensitic transition of a Cu-Al-Be single crystalline shape memory alloy. Both AE and calorimetry corroborate a good power-law behavior for cooling with an exponent ε 1.6. For heating, a slope is observed in the maximum likelihood curves, which confirms that our data are affected by an exponential cutoff. An effective energy exponent, ε ∼ 1.85, and a cutoff, λ −1 = 0.115(38)E-3 aJ, were determined by fits of power-laws with exponential damping. The long tail observed in the low-temperature region by calorimetric measurements suggests the existence of significant elastic effects that constrain the progress of the transformation at low temperatures. While thermodynamic features such as transformation enthalpy and entropy are those expected for Cu-based shape-memory alloys undergoing a cubic ↔ 18R transition, the critical behavior deviates from the corresponding behavior expected from this symmetry change. These deviations are a consequence of the elastic hardening induced by the interplay of the transformation with dislocation jamming, which has the effect of effectively reducing the number of pathways connecting the parent and martensitic phaseMinisterio de Ciencia,Innovación y Universidades (MAT2016-75823-R)Engineering and Physical Sciences Research Council (EP/P024904/1

Statistical similarity between the compression of a porous material and earthquakes

"It has long been stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallels between these so separate phenomena. We study the acoustic emission events produced during the compression of Vycor (SiO2). The Gutenberg-Richter law, the modified Omori's law, and the law of aftershock productivity hold for a minimum of 5 decades, are independent of the compression rate, and keep stationary for all the duration of the experiments. The waiting-time distribution fulfills a unified scaling law with a power-law exponent close to 2.45 for long times, which is explained in terms of the temporal variations of the activity rate.

Regulation of boar sperm functionality by the nitric oxidesynthase/nitric oxide system

Purpose Nitric oxide (NO) is a free radical synthesized mainly by nitric oxide synthases (NOSs). NO regulates many aspects in sperm physiology in different species. However, in vitro studies investigating NOS distribution, and how NO influences sperm capacitation and fertilization (IVF) in porcine, have been lacking. Therefore, our study aimed to clarify these aspects. Methods Two main experiments were conducted: (i) boar spermatozoa were capacitated in the presence/absence of S-nitrosoglutathione (GSNO), a NO donor, and two NOS inhibitors, N-G-nitro-L-arginine methyl ester hydrochloride (L-NAME) and aminoguanidine hemisulfate salt (AG), and (ii) IVF was performed in the presence or not of these supplements, but neither the oocytes nor the sperm were previously incubated in the supplemented media. Results Our results suggest that NOS distribution could be connected to pathways which lead to capacitation. Treatments showed significant differences after 30 min of incubation, compared to time zero in almost all motility parameters (P < 0.05). When NOSs were inhibited, three protein kinase A (PKA) substrates (similar to 75, similar to 55, and similar to 50 kDa) showed lower phosphorylation levels between treatments (P < 0.05). No differences were observed in total tyrosine phosphorylation levels evaluated by Western blotting nor in situ. The percentage of acrosome-reacted sperm and phosphatidylserine translocation was significantly lower with L-NAME. Both inhibitors reduced sperm intracellular calcium concentration and IVF parameters, but L-NAME impaired sperm ability to penetrate denuded oocytes. Conclusions These findings point out to the importance of both sperm and cumulus-oocyte-derived NO in the IVF outcome in porcine.This study was supported by H2020 MSC-ITN-EJD 675526 REP-BIOTECH, the Spanish Ministry of Economy and Competitiveness (MINECO), and the European Regional Development Fund (FEDER), Grant AGL2015-66341-R, and by a grant ESPDOC17/33 (to Jon Romero-Aguirregomezcorta) from the University of the Basque Country (UPV/EHU, Spain)

Elastocaloric effect in Ti-Ni shape-memory wires associated with the B2 ↔ B19' and B2 ↔ R structural transitions

"We have studied the elastocaloric properties of Ti-Ni shape-memory wires subjected to specific heat treatments to decouple the B2 R transition from the B2 B19' one. The entropy values at moderate stresses (similar to 170 MPa) for the B2 B19' transition are remarkably high (in the range 60-80 J/kg K). However, in spite of the B2 R transition exhibits significantly lower entropy changes (similar to 12 J/kg K), the much smaller hysteresis of this transition gives rise to a larger reversible elastocaloric effect for low applied stresses. Therefore, the reversible elastocaloric strength associated with the B2 R is larger than the elastocaloric strength associated with the B2 B19' transition.

Magnetic and structural entropy contributions to the multicaloric effects in Ni-Mn-Ga-Cu

We have studied the multicaloric properties of a Ni-Mn-Ga-Cu alloy. In this alloy, application of magnetic field and uniaxial stress shift its martensitic transition towards higher temperatures which results in synergic magnetocaloric and elastocaloric effects. By a proper numerical treatment of the calorimetric curves obtained under applied magnetic field and uniaxial stress we have obtained the entropy S(T,μ0H,σ) as a function of the magnetic field, uniaxial stress, and temperature over the whole phase space under study. We have determined the different entropy contributions to the multicaloric effect in this alloy, and noticeably we have evidenced the role played by the interplay between magnetic and vibrational degrees of freedom. A comparison between single caloric and multicaloric effects shows that appropriate combinations of magnetic field and stress reduce the magnitude of the specific field required to obtain a given value of the isothermal entropy and adiabatic temperature changes. For example, at 299 K, to achieve an entropy change (ΔS) of −14 J kg−1K−1, a magnetic field of ∼2.5 T or a uniaxial stress of 19 MPa are required, while a combination of dual fields of (1 T, 12 MPa) yields to the same value of ΔS. Moreover, the maximum adiabatic temperature change is enlarged up to 9.4 K by the dual fields, higher than the value obtained by a single field (∼7 K). The advantage of multicaloric effect is particularly relevant at low magnetic fields which are achievable by permanent magnets. Our findings open new avenues for using multicaloric materials in novel refrigeration technologies

RoMoMatteR: Empowering Roma Girls’ Mattering through Reproductive Justice

Aim: To present a protocol study directed at tackling gender discrimination against Roma girls by empowering their mattering so they can envision their own futures and choose motherhood only if—and when—they are ready. Background: Motherhood among Roma girls (RGM) in Europe impoverishes their lives, puts them at risk of poor physical and mental health and precipitates school dropouts. Overwhelming evidence affirms that the conditions of poverty and the social exclusionary processes they suffer have a very important explanatory weight in their sexual and reproductive decisions. Methods: Through a Community-based Participatory Action Research design, 20–25 Roma girls will be recruited in each one of the four impoverished communities in Bulgaria, Romania and Spain. Data collection and analysis: Desk review about scientific evidences and policies will be carried out to frame the problem. Narratives of Roma women as well as baseline and end line interviews of girl participants will be collected through both qualitative and quantitative techniques. Quantitative data will be gathered through reliable scales of mattering, socio–political agency, satisfaction with life and self. A narrative analysis of the qualitative information generated in the interviews will be carried out. Expected results: (1) uncover contextual and psychosocial patterns of girl-motherhood among Roma women; (2) build critical thinking among Roma girls to actively participate in all decisions affecting them and advocate for their own gender rights within their communities; and (3) empower Roma girls and their significant adults to critically evaluate their own initiatives and provide feedback to their relevant stakeholders. Conclusions: Roma girls will improve their educational aspirations and achievements and their social status while respecting and enhancing Roma values.This initiative is funded by the DG Justice of the European Commission in the Call for proposals for action grants under 2017 Rights Equality and Citizenship Work REC-AG #809813

Elastocaloric and magnetocaloric effects in Ni-Mn-Sn(Cu) shape-memory alloy

"We have studied magnetocaloric and elastocaloric properties of a Ni-Mn-Sn(Cu) metamagnetic shape-memory alloy undergoing a magneto-structural transition (martensitic type) close to room temperature. Changes of entropy have been induced by isothermally applying both mechanical (uniaxial stress) and magnetic fields. These entropy changes have been, respectively, estimated from dilatometric measurements giving the length of the sample as a function of temperature at selected applied forces and magnetic fields and from magnetization measurements as a function of temperature at selected applied magnetic fields. Our results indicate that the elastocaloric effect is conventional and occurs in two steps which reflect the interplay between the martensitic and the incipient magnetic transitions. By contrast, the magnetocaloric effect is inverse and occurs in a single step that encompasses the effect arising from both transitions.

Influence of Fe doping and magnetic field on martensitic transition in Ni–Mn–Sn melt-spun ribbons

"Mn-rich Ni-Mn-Sn metamagnetic shape memory alloys exhibiting magnetostructural transformation are of a great potential as the base materials for solid-state refrigeration. With the aim of fine tuning of the transformation characteristics and improving functional properties, in the present work we have fabricated polycrystalline Ni50-xFexMn40Sn10 (x = 0, 2, 4, 6, 8 at.%) melt-spun ribbons, starting from the base alloy with x = 0, which is weakly magnetic in both austenitic and martensitic phases. By exploring martensitic transformation (MT) and magnetic behaviors as a function of Fe doping and magnetic field, we have found that Fe and/or magnetic field reduce the MT temperature and Curie temperature of austenite phase, becoming closer to each other as the Fe-content increases, accompanied by an increase of the magnetic moment of austenite, magnetization jump at MT, transformation volume, and magnetic contribution, Delta S-M, to the total entropy change at MT. The ribbons present moderate values of Delta S-M equal to 11 J kg(-11)K(-1) at 5 T for x = 8, moderate thermal hysteresis (10-14 K) nearly independent of Fe doping or magnetic field, and adjustable structural and magnetic transition temperatures close to room temperature. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Flexible ureterorenoscopy : State of the art and practical guide of tips and tricks

La ureterorrenoscopia flexible es cada vez más utilizada como tratamiento de primera línea para pacientes con litiasis renal y del uréter proximal, con tasas de éxito variables entre los diferentes grupos de autores y con gran heterogeneidad a la hora de definir el tamaño mínimo para definir tasa libre de cálculo. Se presenta una revisión de la literatura sobre el estado del arte en ureterorrenoscopia flexible, se aclaran diferentes conceptos y se exponen consejos y trucos que se han implementado en un centro de referencia para el manejo de litiasis urinaria, con el objetivo de disminuir las complicaciones, mejorar la tasa libre de cálculos y mejorar el desempeño del procedimiento al urólogo.Q4Artículo de revisión239-249Flexible ureterorenoscopy is being used as first line treatment for kidney stones and proximal ureteral calculi, with variable success rates between different authors and lack of heterogeneity to define the minimal lithiasic mass in the stone free rate concept. The aim of this article is to present a descriptive analysis of the state of the art in flexible ureterorenoscopy as the preferred modern stone therapy, the tips and tricks that are setting the pace, and the tips and tricks of a reference centre for stone disease. In order to ensure high effectiveness combined with a low complication rate and a low stone free rate thus to make flexible ureterorenoscopy easier than ever