8,428 research outputs found

    Gauge invariant MSSM inflaton

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    We argue that all the necessary ingredients for successful inflation are present in the flat directions of the Minimally Supersymmetric Standard Model. We show that out of many gauge invariant combinations of squarks, sleptons and Higgses, there are two directions, LLe{\bf LLe}, and udd{\bf udd}, which are promising candidates for the inflaton. The model predicts more than 10310^3 e-foldings with an inflationary scale of HinfO(110)H_{\rm inf}\sim {\cal O}(1-10) GeV, provides a tilted spectrum with an amplitude of δH105\delta_H\sim 10^{-5} and a negligible tensor perturbation. The temperature of the thermalized plasma could be as low as TrhO(110)T_{rh}\sim {\cal O}(1-10)~TeV. Parts of the inflaton potential can be determined independently of cosmology by future particle physics experiments.Comment: 4 revtex pages, some references added, stabilization of moduli and supergravity effects are discusse

    Postoperative pain and morphine consumption after ultrasound-guided femoral and sciatic combined nerve block versus neurostimulation for femoral and sciatic combined nerve block or neurostimulation for femoral nerve block in primary elective total knee arthroplasty.

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    Abstract Congreso XXXVII National Meeting of the Spanish Society of Pharmacology with guest society: The British Pharmacological SocietyBackground and Aims: Total knee arthroplasty injuries are extremely painful and merit prompt attention to adequate postoperative analgesia. We aim to compare femoral and sciatic ultrasound-guided combined nerve block vs. neurostimulation for femoral and sciatic combined nerve block or for femoral nerve block in postoperative pain in primary elective total knee prosthesis. Summary of work and outcomes: A three arms, prospective longitudinal study of patients having primary elective unilateral knee prosthesis and randomly assigned to catheter insertion guided by ultrasound or neurostimulation was done: 1) Ultrasound-guided femoral and sciatic combined nerve block (USFSCN) (N=15); 2) Neurostimulation for femoral and sciatic combined nerve block (NSFSCN) (N=17); 3) Neurostimulation for femoral nerve block (NSFN) (N=11). Total analgesia (morphine) consumption after 48 hours was the primary endpoint. The postoperative pain intensity (visual analogue pain scale (VAS)) at post-anaesthetic recovery unit (PARU), 6, 24, 48 h, and during movement and postoperative complications were secondary outcomes. Results and discussion: 43 patients (68.3±8 years old, 77% female) subjected to elective unilateral knee prosthesis were enrolled. There were no differences in the demographic, anaesthetic and surgical variables between groups. Pain intensity was lower in the USFSCN group compared with NSFSCN and NSFN during the first 48 h post-surgery (% of intense pain at PARU/6h/24h/48h): USFSCN 0.8/1.4/3.2/1.6; NSFSCN 5.6/8.3/7.5/3; NSFN 7.2/5.3/6.4/5.4. The average consumption of morphine within 48 h after surgery was similar in the groups USFSCN and NSFSCN (3 mg vs. 3.11 mg), and significantly lower than NSFN (4.19 mg) (p<0.05). And the number of complications was significantly lower in the USFSCN group compared with NSFSCN and NSFN during the first 48 h of postoperative. Conclusion: Ultrasound-guided femoral and sciatic combined nerve block presented better analgesia and was more safety than neurostimulation for femoral and sciatic combined nerve block or for femoral nerve block in primary elective total knee arthroplasty.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Variation propagation of bench vises in multi-stage machining processes

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    Comunicación presentada a MESIC 2019 8th Manufacturing Engineering Society International Conference (Madrid, 19-21 de Junio de 2019)Variation propagation has been successfully modeled by the Stream of Variation (SoV) approach in multistage machining processes. However, the SoV model basically supports 3-2-1 fixtures based on punctual locators and other workholding systems such as conventional vises are not considered yet. In this paper, the SoV model is expanded to include the fixture- and datum-induced variations on workholding devices such as bench vises. The model derivation is validated through assembly and machining simulations on Computer Aided Design software. The case study analyzed shows an average error of part quality prediction between the SoV model and the CAD simulations of 0.26%

    Lambda-inflation and CMB anisotropy

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    We explore a broad class of three-parameter inflationary models, called the Λ\Lambda-inflation, and its observational predictions: high abundance of cosmic gravitational waves consistent with the Harrison-Zel'dovich spectrum of primordial cosmological perturbations, the non-power-law wing-like spectrum of matter density perturbations, high efficiency of these models to meet current observational tests, and others. We show that a parity contribution of the gravitational waves and adiabatic density perturbations into the large-scale temperature anisotropy, T/S 1\sim 1, is a common feature of Λ\Lambda-inflation; the maximum values of T/S (basically not larger than 10) are reached in models where (i) the local spectrum shape of density perturbations is flat or slightly red (nS<1n_S{}_\sim^< 1), and (ii) the residual potential energy of the inflaton is near the GUT scale (V01/41016GeVV_0^{{1/4}} \sim 10^{16} GeV). The conditions to find large T/S in the paradigm of cosmic inflation and the relationship of T/S to the ratio of the power spectra, rr, and to the inflationary γ\gamma and Hubble parameters, are discussed. We argue that a simple estimate, T/S3r12γ(H6×1013GeV)2\simeq 3r\simeq 12\gamma \simeq (\frac{H}{6\times 10^{13}{\rm GeV}})^2, is true for most known inflationary solutions and allows to relate straightforwardly the important parameters of observational and physical cosmology.Comment: 29 pages, 3 figures include

    Incorporation of form deviations into the matrix transformation method for tolerance analysis in assemblies

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    Comunicación presentada a MESIC 2019 8th Manufacturing Engineering Society International Conference (Madrid, 19-21 de Junio de 2019)Mathematical models for tolerance representation are used to assess how the geometrical variation of a specific component feature propagates along the assembly, so that tolerance analysis in assemblies can be carried out using a specific tolerance propagation method. Several methods for tolerance analysis have been proposed in the literature, being some of them implemented in CAD systems. All these methods require modelling the geometrical variations of the component surfaces: parametric models, variational models, DoF models, etc. One of the most commonly used models is the DoF model, which is employed in a number of tolerance analysis methods: Small Displacement Torsor (SDT), Technologically and Topologically Related Surfaces (TTRS), Matrix Transformation, Unified Jacobian–Torsor model. However, none of the DoF-based tolerance analysis methods incorporates the effect of form deviations. Among the non DoF-based methods, there are two that include form tolerances: the Vector Loop or Kinematic method and the Tolerance Map (T-Map) model, although the latter is still under development. In this work, a proposal to incorporate form deviations into the matrix transformation method for tolerance analysis in assemblies is developed using a geometrical variation model based on the DoF model. The proposal is evaluated applying it to a 2D case study with components that only have flat surfaces, but the proposal can be extrapolated to 3D cases

    Transformations due to mylonitization processes in granitic rocks

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    [Resumen] El objetivo de este estudio es determinar las transformaciones, tanto a nivel mineralógico como textural, experimentadas por rocas graníticas tardihercínicas afectadas por procesos de milonitización en el sector oriental de la Sierra de Gredos (Sistema Central Español). De igual modQ se intenta determinar la influencia de dichas transformaciones en la composición química de las rocas milonitizadas . El incremento progresivo de la deformación provoca una serie de transformaciones texturales en las que a partir de granitoides de grano grueso porfídicos se generan unas milonitas porfidoclásticas planolineares en el núcleo de la banda de fractura. Desde el punto de vista mineralógico se aprecia una total trituración y degradación de la biotita, que se transforma a clorita de grano muy fino dispersa en la matriz milonítica. También se observan ciertas removilizaciones de feldespato potásico y albita y reajustes metamórficos de bajo grado (en facies de esquistos verdes). Los cambios composicionales acompañantes consisten en un enriquecimiento en Si02, CaO y Na20 en la zona de máxima milonitización y un empobrecimiento en K20 y P20 S en el mismo sentido. En cuanto a los elementos traza, tan sólo Rb y Sr muestran un ligero empobrecimiento en la zona milonítica.[Abstract] The aim of this paper is the determination of the textural and mineralogical transformations introduced in late-Hercynian granitic rocks which have undergone mylonitization processes in the Eastern Sierra de Gredos (Spanish Central System). It also is intended to determine the influence of such changes on the chemical composition of the mylonitic rocks. The progressive increasing of strain causes a series of textural transformations in the originally porphyritic, coarse-grained granitoids leading to formation of porphyroclastic mylonitic rocks with development of planelinear fabrics at the core of the fracture zone. From a mineralogical point of view, transformation~ consist in entire crushing and degradation of biotite, which converts into very fine-grained chlorite disseminated within the mylonitic matrix. Likewise, K-feldspar and albite remobilizations and low grade (greenschists facies) metamorphic readjustments can be observed. The accompanying compositional changes are Si02, CaO and Na20 enrichment and K20 and P20S impoverishment towards the zone of maximum mylonitization. Concerning the trace elements, only Rb and Sr show a weak impoverishment within the mylonitic zone

    Solutions of gauge invariant cosmological perturbations in long-wavelength limit

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    We investigate gauge invariant cosmological perturbations in a spatially flat Friedman-Robertson-Walker universe with scalar fields. It is well known that the evolution equation for the gauge invariant quantities has exact solutions in the long-wavelength limit. We find that these gauge invariant solutions can be obtained by differentiating the background solution with respect to parameters contained in the background system. This method is very useful when we analyze the long-wavelength behavior of cosmological perturbation with multiple scalar fields.Comment: 17 pages, will appear in Classical and Quantum Gravit

    Velocity dispersions of clusters in the Dark Energy Survey Y3 redMaPPer catalogue

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    Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereThis is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Monthly Notices of the Royal Astronomical Society 514.4 (2022): 4696-4717 is available online at: https://academic.oup.com/mnras/article-abstract/514/4/4696/6615472We measure the velocity dispersions of clusters of galaxies selected by the redMaPPer algorithm in the first three years of data from the Dark Energy Survey (DES), allowing us to probe cluster selection and richness estimation, , in light of cluster dynamics. Our sample consists of 126 clusters with sufficient spectroscopy for individual velocity dispersion estimates. We examine the correlations between cluster velocity dispersion, richness, X-ray temperature and luminosity as well as central galaxy velocity offsets. The velocity dispersion-richness relation exhibits a bimodal distribution. The majority of clusters follow scaling relations between velocity dispersion, richness, and X-ray properties similar to those found for previous samples; however, there is a significant population of clusters with velocity dispersions which are high for their richness. These clusters account for roughly 22% of the 0.5. A couple of these systems are hot and X-ray bright as expected for massive clusters with richnesses that appear to have been underestimated, but most appear to have high velocity dispersions for their X-ray properties likely due to line-of-sight structure. These results suggest that projection effects contribute significantly to redMaPPer selection, particularly at higher redshifts and lower richnesses. The redMaPPer determined richnesses for the velocity dispersion outliers are consistent with their X-ray properties, but several are X-ray undetected and deeper data is needed to understand their natur

    Gravitational waves from self-ordering scalar fields

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    Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively studied in the literature. In this paper we analyze the shape and amplitude of the gravitational wave spectrum on scales which are superhorizon at the time of production. Such gravitational waves are expected from the self ordering of randomly oriented scalar fields which can be present during a thermal phase transition or during preheating after hybrid inflation. We find that, if the gravitational wave source acts only during a small fraction of the Hubble time, the gravitational wave spectrum at frequencies lower than the expansion rate at the time of production behaves as ΩGW(f)f3\Omega_{\rm GW}(f) \propto f^3 with an amplitude much too small to be observable by gravitational wave observatories like LIGO, LISA or BBO. On the other hand, if the source is active for a much longer time, until a given mode which is initially superhorizon (kη1k\eta_* \ll 1), enters the horizon, for kη1k\eta \gtrsim 1, we find that the gravitational wave energy density is frequency independent, i.e. scale invariant. Moreover, its amplitude for a GUT scale scenario turns out to be within the range and sensitivity of BBO and marginally detectable by LIGO and LISA. This new gravitational wave background can compete with the one generated during inflation, and distinguishing both may require extra information.Comment: 21 pages, 2 figures, added discussion about numerical integration and a new figure to illustrate the scale-invariance of the GW power spectrum, conclusions unchange
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