Aplicación de la función densidad electrónica para diferenciar la estructura de la corrensita y de la clorita-clorita hinchable

El estudio por difracción de rayos X de interestratificados de minerales de la arcilla es de gran utilidad en la investigación geológica de los materiales arcillosos. El analisis de los espectros de difracción de interestratificados regulares utilizando los metodos de "tanteo" de determinación de estructuras cristalinas asi como los basados en la transformada de Fourier, permite obtener una información mas relacionada con el interestratificado que con la muestra arcillosa global en el caso de estudiar muestras no puras, mejor que los métodos quimicos en los que se basan un gran número de conclusiones de tipo estructural. La aplicación de la transformada de Fourier para la función de mezcla asi como de la función densidad electrónica pone de manifiesto que las estructuras de los interestratificados regulares de cloritaclorita hinchable y de clorita-esmectita son distintas, a pesar de ser utilizada indistintamente por algunos autores la denominación de corrensita para ambos interestratificados

Formulation and constraints on decaying dark matter with finite mass daughter particles

Decaying dark matter cosmological models have been proposed to remedy the overproduction problem at small scales in the standard cold dark matter paradigm. We consider a decaying dark matter model in which one CDM mother particle decays into two daughter particles, with arbitrary masses. A complete set of Boltzmann equations of dark matter particles is derived which is necessary to calculate the evolutions of their energy densities and their density perturbations. By comparing the expansion history of the universe in this model and the free-streaming scale of daughter particles with astronomical observational data, we give constraints on the lifetime of the mother particle, $\Gamma^{-1}$, and the mass ratio between the daughter and the mother particles $m_{\rm D}/m_{\rm M}$. From the distance to the last scattering surface of the cosmic microwave background, we obtain $\Gamma^{-1}>$ 30 Gyr in the massless limit of daughter particles and, on the other hand, we obtain $m_{\rm D} >$ 0.97$m_{\rm M}$ in the limit $\Gamma^{-1}\to 0$. The free-streaming constraint tightens the bound on the mass ratio as $(\Gamma^{-1}/10^{-2}{\rm Gyr}) \lesssim ((1-m_{\rm D1}/m_{\rm M})/10^{-2})^{-3/2}$ for $\Gamma^{-1} < H^{-1}(z=3)$.Comment: 20 pages, 7 figure

Analysis of solar direct irradiance models under clear-skies: Evaluation of the improvements for locally adapted models

Direct solar irradiance has to be determined for the design of many energy applications such as photovoltaic systems and concentration systems, and the generation of solar potential maps for energy use. Knowledge of the accurate values of radiation components in a local area will allow optimal sizing of solar energy conversion systems. The estimated values of direct solar irradiance from models are still necessary at those sites where no measurements are available. In this work, different models used for the estimation of the direct component of solar irradiance are analyzed. First, an evaluation of the performance of eight existing original models was performed from which three were selected. Second, the selected models were calibrated to adapt them to our studied geographical area, which is the important aspect of this work, and an assessment of performance improvements for locally adapted models is reported. Experimental data consisted of hourly horizontal global, direct, and diffuse solar irradiance values, provided by the National Meteorological Agency in Spain (AEMET) for Madrid. Long-term data series, corresponding to a total period of time of 32 years (1980–2011), have been used in this study. Only clear sky models were treated at present. The three selected models were adapted to the specific location of Madrid, and root mean square error (RMSE) and mean-biased error were determined. By comparing the performance in the direct horizontal irradiance estimation from existing original and the corresponding locally adapted models, it is found that the values of RMSE decreased from 9.9% to 5.7% for the Louche model, from 7.8% to 7.4% for the Robledo-Soler model, and finally from 8.8% to 6.7% for the European Solar Radiation Atlas model. Thus, significant improvements can be reached when parametric models are locally adapted. In our case, it is up to approximately 4% for the Louche model. It is expected that calibrated algorithms presented in this work will be applicable to regions of similar climatic characteristics.Spanish Government (grant ENE2011-27511) and the Department of Culture and Education of the Regional Government of Castilla y León, Spain (grant BU358A12-2

Geobotanical survey of Cabo Verde Islands (West Africa)

The results of the study of the bioclimate, biogeography, flora and vegetation of Cabo Verde Islands, after seven years of field works in all inhabited isles are presented in this paper. Tropical hyperdesertic to pluviseasonal, upper infra- to low supratropical and upper ultrahyperarid to upper dry, and occasionaly lower subhumid (short period years), are the bioclimates in these archipelago. Biogeographically they are situated in the Paleotropical Kingdom, Afrotropical Subkingdom, Tropical Saharan Region, and Cabo Verde Province. Eight new species are described: Acacia caboverdeana, Asphodelus mariolousae, Frankenia pseudoericifolia, Hyparrhenia caboverdeana, Lotus chevalieri, Polycarpaea caboverdeana, Suaeda caboverdeana and Tetraena vicentina, and also fifteen new combinations are proposed. In taxonomic phytosociology, five new classis: Cocculo penduli-Sarcostemmetea daltonii, Heteropogonetea contorti, Tetraenetea simplicis, Frankenio pseudoericifoliae-Suaedetea caboverdeanae and Arthrocnemetea franzii; nine new orders: Euphorbio tuckeyanae-Sarcostemmetalia daltonii, Dichrostachyo platycarpae-Acacietalia caboverdeanae, Melinio grandiflorae-Heteropogonetalia contorti, Aristido cardosoi-Tetraenetalia simplicis, Frankenio pseudoericifoliae-Suaedetalia caboverdeanae, Artrocnemetalia franzii, Sesuvietalia sesuvioidis, Kickxietalia elegantis and Euphorbietalia prostrato-hirtae; fourteen new alliances: Asparago squarrosi-Sarcostemmion daltonii, Globulario amygdalifoliae- Periplocion chevalieri, Fico gnaphalocarpae-Acacion caboverdeanae, Phoenicion atlanticae, Tamaricion senegalensis, Heteropogonion melanocarpo-contorti, Aristido cardosoi-Tetraenion simplicis, Polycarpaeo caboverdeanae-Tetraenion waterlotii, Arthrocnemion franzii, Sesuvion sesuvioidis, Adiantion trifidi, Kickxion elegantis, Adiantion incisophilippensis and Trianthemion portulacastri and, finally, fifty two new associations: Cocculo penduli-Sarcostemmetum daltonii, Campylantho spathulati-Sarcostemmetum daltonii, Frankenio caboverdeanae-Asparagetum squarrosi, Aeonio gogonei-Sarcostemmetum daltonii, Echio stenosiphonis-Euphorbietum tuckeyanae, Suaedo caboverdeanae-Asparagetum squarrosii, Tetraeno waterlotii-Sarcostemmetum daltonii, Erysimo caboverdeanae-Periplocetum chevalieri, Echietum vulcanori, Actinopterido radiatae-Sarcostemmetum daltonii, Echio hypertropici-Euphorbietum tuckeyanae, Launaeo thalassicae-Euphorbietum tuckeyanae, Loto latifolii-Artemisietum gogonei, Melanoselino bischoffii-Globularietum amygdalifoliae, Asterisco smithii-Euphorbietum tuckeyanae, Dichrostachyo platycarpae-Acacietum caboverdeanae, Cocculo penduli-Acacietum caboverdeanae, Forsskaoleo procridifoliae-Acacietum caboverdeanae, Cocculo penduli-Ficetum gnaphalocarpae, Forsskaoleo procridifoliae-Ficetum gnaphalocarpae, Dichrostachyo platycarpae-Ficetum sur, Euphorbio tuckeyanae-Ficetum sur, Sideroxyletum marginati, Dracaenetum caboverdeanae, Cocculo penduli-Phoenicetum atlanticae, Cocculo penduli-Tamaricetum senegalensis, Dichanthio foveolati-Heteropogonetum contorti, Heteropogonetum melanocarpi, Bothriochloo bladhii-Enneapogonetum desvauxii, Aristido cardosoi- Tetraenetum simplicis, Asphodelo mariolousae-Aristidetum cardosoi, Sehimatetum ischaemoidis, Polycarpaeo caboverdeanae-Tetraenetum waterlotii, Tetraenetum vicentinae, Sporobolo spicati-Cyperetum crassipedis, Loto brunneri- Pulicarietum diffusae, Arthrocnemetum franzii, Cressetum salinae, Sesuvietum sesuvioidis, Sesuvietum portulacastri, Blutaparonetum vermicularis, Adiantetum trifidi, Hypodematio crenati-Campanuletum bravensis, Kickxietum webbianae, Diplotaxio hirtae-Kickxietum elegantis, Umbilico schmidtii-Cheilanthetum acrosticae, Campanuletum jacobaeae, Campanulo bravensis-Launaetum thalassicae, Adiantetum inciso-philippensis, Trianthemetum portulacastri, Euphorbio hirtae-Boerhavietum repentis and Oldenlandietum corymbosae are proposed and describedinfo:eu-repo/semantics/publishedVersio

Observation of nuclear-spin Seebeck effect

Thermoelectric effects have been applied to power generators and temperature sensors that convert waste heat into electricity. The effects, however, have been limited to electrons to occur, and inevitably disappear at low temperatures due to electronic entropy quenching. Here, we report thermoelectric generation caused by nuclear spins in a solid: nuclear-spin Seebeck effect. The sample is a magnetically ordered material MnCO3 having a large nuclear spin (I = 5/2) of 55Mn nuclei and strong hyperfine coupling, with a Pt contact. In the system, we observe low-temperature thermoelectric signals down to 100 mK due to nuclear-spin excitation. Our theoretical calculation in which interfacial Korringa process is taken into consideration quantitatively reproduces the results. The nuclear thermoelectric effect demonstrated here offers a way for exploring thermoelectric science and technologies at ultralow temperaturesThis work was supported by JST ERATO “Spin Quantum Rectification Project” (JPMJER1402), JST CREST (JPMJCR20C1 and JPMJCR20T2), JSPS KAKENHI (JP19H05600, JP19K21031, JP20H02599, JP20K22476, and JP20K15160), MEXT [Innovative Area “Nano Spin Conversion Science” (JP26103005)], and Daikin Industries, Ltd. The work at UCLA was supported by the US Department of Energy, Office of Basic Energy Sciences under Award number DE-SC0012190. K.O. acknowledges support from GP-Spin at Tohoku University. R.R. acknowledges support from the European Commission through the project 734187-SPICOLOST (H2020-MSCA-RISE-2016), the European Union’s Horizon 2020 research and innovation program through the Marie Sklodowska-Curie Actions grant agreement SPEC number 894006 and the Spanish Ministry of Science (RYC 2019-026915-I)S

A natural little hierarchy for RS from accidental SUSY

We use supersymmetry to address the little hierarchy problem in Randall-Sundrum models by naturally generating a hierarchy between the IR scale and the electroweak scale. Supersymmetry is broken on the UV brane which triggers the stabilization of the warped extra dimension at an IR scale of order 10 TeV. The Higgs and top quark live near the IR brane whereas light fermion generations are localized towards the UV brane. Supersymmetry breaking causes the first two sparticle generations to decouple, thereby avoiding the supersymmetric flavour and CP problems, while an accidental R-symmetry protects the gaugino mass. The resulting low-energy sparticle spectrum consists of stops, gauginos and Higgsinos which are sufficient to stabilize the little hierarchy between the IR scale and the electroweak scale. Finally, the supersymmetric little hierarchy problem is ameliorated by introducing a singlet Higgs field on the IR brane.Comment: 37 pages, 3 figures; v2: minor corrections, version published in JHE

Quantum dynamics of crystals of molecular nanomagnets inside a resonant cavity

It is shown that crystals of molecular nanomagnets exhibit enhanced magnetic relaxation when placed inside a resonant cavity. Strong dependence of the magnetization curve on the geometry of the cavity has been observed, providing evidence of the coherent microwave radiation by the crystals. A similar dependence has been found for a crystal placed between Fabry-Perot superconducting mirrors. These observations open the possibility of building a nanomagnetic microwave laser pumped by the magnetic field

Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection

Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the presence of substructure. Although an application of the approach presented here would likely be feasible with current experiments only for very optimistic dark matter scenarios, the improved sensitivity of upcoming experiments could enable this technique to be used to study a wider range of dark matter models.Comment: 29 pp, 8 figs; replaced to match published version (minor changes and some new references

The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast

The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al

Electroweak Baryogenesis and Dark Matter with an approximate R-symmetry

It is well known that R-symmetric models dramatically alleviate the SUSY flavor and CP problems. We study particular modifications of existing R-symmetric models which share the solution to the above problems, and have interesting consequences for electroweak baryogenesis and the Dark Matter (DM) content of the universe. In particular, we find that it is naturally possible to have a strongly first-order electroweak phase transition while simultaneously relaxing the tension with EDM experiments. The R-symmetry (and its small breaking) implies that the gauginos (and the neutralino LSP) are pseudo-Dirac fermions, which is relevant for both baryogenesis and DM. The singlet superpartner of the U(1)_Y pseudo-Dirac gaugino plays a prominent role in making the electroweak phase transition strongly first-order. The pseudo-Dirac nature of the LSP allows it to behave similarly to a Dirac particle during freeze-out, but like a Majorana particle for annihilation today and in scattering against nuclei, thus being consistent with current constraints. Assuming a standard cosmology, it is possible to simultaneously have a strongly first-order phase transition conducive to baryogenesis and have the LSP provide the full DM relic abundance, in part of the allowed parameter space. However, other possibilities for DM also exist, which are discussed. It is expected that upcoming direct DM searches as well as neutrino signals from DM annihilation in the Sun will be sensitive to this class of models. Interesting collider and Gravity-wave signals are also briefly discussed.Comment: 50 pages, 10 figure