Anomaly-free constraints in neutrino seesaw models

The implementation of seesaw mechanisms to give mass to neutrinos in the presence of an anomaly-free U(1)_X gauge symmetry is discussed in the context of minimal extensions of the standard model. It is shown that type-I and type-III seesaw mechanisms cannot be simultaneously implemented with an anomaly-free local U(1)_X, unless the symmetry is a replica of the well-known hypercharge. For combined type-I/II or type-III/II seesaw models it is always possible to find nontrivial anomaly-free charge assignments, which are however tightly constrained, if the new neutral gauge boson is kinematically accessible at LHC. The discovery of the latter and the measurement of its decays into third-generation quarks, as well as its mixing with the standard Z boson, would allow one to discriminate among different seesaw realizations.Comment: 5 pages, 3 figures; final version to appear in Phys. Rev.

Electrical conductivity of metal (hydr)oxide–activated carbon composites under compression. A comparison study

[EN]From a granular commercial activated carbon (AC) and six metal (hydr)oxide precursors, including Al(NO3)3, Fe(NO3)3, SnCl2, TiO2, Na2WO4 and Zn(NO3)2, a broadly varied series of metal (hydr)oxideeAC composites were prepared by wet impregnation and subsequent oven-drying at 120 C. Here, the electrical conductivity of the resulting products was studied under moderate compression. The influence of the applied pressure, sample volume, mechanical work, and density of the hybrid materials was thoroughly investigated. The dc electrical conductivity of the compressed samples was measured at room temperature by the four-probe method. Compaction assays show that the mechanical properties of the composites are largely determined by the carbon matrix. Both the decrease in volume and the increase in density under compression were very small and only significant at pressures lower than 100 kPa for AC and most composites. By contrast, the bulk electrical conductivity of the hybrid materials was strongly influenced by the nature, content and intrinsic conductivity of the supported metal phases, which act as insulating thin layers thereby hindering the effective electron transport between AC cores of neighbouring sample particles in contact under compression. Conductivity values for the composites were lower than for the raw AC, all of them falling in the range of typical semiconductor materials. The patterns of variation of the electrical conductivity with pressure and mechanical work were slightly similar, thus suggesting the predominance of the pressure effects rather than the volume one

A Multiple System of Radio Sources at the Core of the L723 Multipolar Outflow

We present high angular resolution Very Large Array multi-epoch continuum observations at 3.6 cm and 7 mm towards the core of the L723 multipolar outflow revealing a multiple system of four radio sources suspected to be YSOs in a region of only ~4 arcsecs (1200 AU) in extent. The 3.6 cm observations show that the previously detected source VLA 2 contains a close (separation ~0.29 arcsecs or ~90 AU) radio binary, with components (A and B) along a position angle of ~150 degrees. The northern component (VLA 2A) of this binary system is also detected in the 7 mm observations, with a positive spectral index between 3.6 cm and 7 mm. In addition, the source VLA 2A is associated with extended emission along a position angle of ~115 degrees, that we interpret as outflowing shock-ionized gas that is exciting a system of HH objects with the same position angle. A third, weak 3.6 cm source, VLA 2C, that is detected also at 7 mm, is located ~0.7 arcsecs northeast of VLA 2A, and is possibly associated with the water maser emission in the region. The 7 mm observations reveal the presence of an additional source, VLA 2D, located ~3.5 arcsecs southeast of VLA 2A, and with a 1.35 mm counterpart. All these radio continuum sources have a positive spectral index, compatible with them being YSOs. We also propose that the high velocity CO emission observed in the region could be the superposition of multiple outflows (at least three independent bipolar outflows) excited by the YSOs located at the core, instead of the previous interpretations in terms of only one or two outflows.Comment: Accepted for publication in The Astrophysical Journal (2007 December 6

Relativistic two-body currents for one-nucleon knockout in electron-nucleus scattering

We present a detailed study of the contribution from two-body currents to the one-nucleon knockout process induced by electromagnetic interaction. The framework is a relativistic mean-field model (RMF) in which bound and scattering nucleons are consistently described as solutions of Dirac equation with potentials. We show results obtained with the most general expression of the two-body operator, in which the intermediate nucleons are described by relativistic mean-field bound states; then, we propose two approximations consisting in describing the intermediate states as nucleons in a relativistic Fermi gas, preserving the complexity and consistency in the initial and final states. These approximations simplify the calculations considerably, allowing us to provide outcomes in a reasonable computational time. The results obtained under these approximations are validated by comparing with those from the full model. Additionally, the theoretical predictions are compared with experimental data of the longitudinal and transverse responses of carbon 12. The agreement with data is outstanding for the longitudinal response, where the contribution from the two-body operator is negligible. In the transverse sector, the two-body current increases the response from 30 to 15%, depending on the approximations and kinematics, in general, improving the agreement with data.Comment: 11 pages, 5 figure

Co-prescription patterns of cardiovascular preventive treatments: A cross-sectional study in the Aragon worker' health study (Spain)

Objectives: To identify cardiovascular disease (CVD) preventive treatments combinations, among them and with other drugs, and to determine their prevalence in a cohort of Spanish workers. Design: Cross-sectional study. Setting Aragon Workers'' Health Study (AWHS) cohort in Spain. Participants 5577 workers belonging to AWHS cohort. From these subjects, we selected those that had, at least, three prescriptions of the same therapeutic subgroup in 2014 (n=4605). Primary and secondary outcome measures Drug consumption was obtained from the Aragon Pharmaceutical Consumption Registry (Farmasalud). In order to know treatment utilisation, prevalence analyses were conducted. Frequent item set mining techniques were applied to identify drugs co-prescription patterns. All the results were stratified by sex and age. Results: 42.3% of men and 18.8% of women in the cohort received, at least, three prescriptions of a CVD preventive treatment in 2014. The most prescribed CVD treatment were antihypertensives (men: 28.2%, women 9.2%). The most frequent association observed among CVD preventive treatment was agents acting on the renin-angiotensin system and lipid-lowering drugs (5.1% of treated subjects). Co-prescription increased with age, especially after 50 years old, both in frequency and number of associations, and was higher in men. Regarding the association between CVD preventive treatments and other drugs, the most frequent pattern observed was lipid-lowering drugs and drugs used for acid related disorders (4.2% of treated subjects). Conclusions: There is an important number of co-prescription patterns that involve CVD preventive treatments. These patterns increase with age and are more frequent in men. Mining techniques are a useful tool to identify pharmacological patterns that are not evident in the individual clinical practice, in order to improve drug prescription appropriateness

Semi-inclusive charged-current neutrino-nucleus cross sections in the relativistic plane-wave impulse approximation

Neutrino-nucleus quasielastic scattering is studied in the plane-wave impulse approximation for three nuclear models: the relativistic Fermi gas (RFG), the independent-particle shell model (IPSM), and the natural orbitals (NO) model with Lorentzian dependence of the excitation energy. A complete study of the kinematics of the semi-inclusive process and the associated cross sections are presented and discussed for 40Ar and 12C. Inclusive cross sections are also obtained by integrating the semi-inclusive expressions over the outgoing hadron. Results are consistent with previous studies restricted to the inclusive channel. In particular, a comparison with the analytical results for the RFG model is performed. Explicit expressions for the hadronic tensor and the 10 semiinclusive nuclear responses are given. Theoretical predictions are compared with semi-inclusive experimental data from T2K experiment.Ministerio de Ciencia, Innovación y Universidades de España y FEDER (Fondo Europeo de Desarrollo Regional). FIS2017-88410-PJunta de Andalucía. FQM160 y SOMM17/6105/UG

The impact on plant communities of an invasive alien herb, Oenothera drummondii, varies along the beach-coastal dune gradient

One of the major threats to the diversity of coastal dunes is the expansion of invasive species, such as Oenothera drummondii subsp. drummondii (Onagraceae). In southwestern Spain, we studied the impact of this American invasive on community structure and composition along a beach-dune gradient (beach, foredune, and inland dunes). Differences in density, biomass, and the cover of O. drummondii, the cover of perennial and annuals/biennials species, and Shannon diversity index H’ and dominance λ were compared between invaded and uninvaded sectors. We observed that the intensity and impact of the invasion by O. drummondii varies along the beach-dune gradient. The abundance of the invasive plant increased inland and in consequence, its impact on species richness and composition was highest in inland dunes. Here, plant cover of O. drummondii represented 57.9% of total plant cover; species richness was reduced (with 3.3 fewer species per 2 × 2m plot), diversity H’ was lower while dominance λ was higher. At a broader scale, species richness in the invaded sector was 25% larger than in the uninvaded sector, because of the presence of ruderal species. Species composition also was modified after the invasion. The abundance of a keystone native species was largely reduced (Ammophila arenaria), and some natives became locally extinct (Otanthus maritimus, Eryngium maritimum, Medicago marina and Elymus farctus). We conclude that the high environmental severity of the beach and foredunes results in a reduced invasion and impact of O. drummondii, whereas the milder conditions of inland dunes promote its expansion. The shift in community structure and composition can have an increasing domino effect and thus monitoring, and mitigation actions are necessary. When doing so, the environmental heterogeneity of the beach-dune gradient should be considered, given its relevance in the invasion process.Ministerio de Economía y Competitividad CGL2015-65058-RConsejo Nacional de Ciencia y Tecnología (CONACYT) 779

Multiple seed dispersal modes of an invasive plant species on coastal dunes

Beach evening-primrose (Oenothera drummondii subsp. drummondii) is a perennial herb native to the coastal dunes of the Gulf of Mexico and southeastern USA. During the last century, the species was unintentionally introduced into coastal dune systems around the world. The purpose of this study was to explore the means of dispersal of this invasive in the newly established populations on the coastal dunes of Spain and to determine if they contribute significantly to the invasion process. After reconstructing the history of its spread in Spain from available records, we tested whether dispersion by marine currents can be a mechanism of colonization at regional scale, and whether the presence of native vertebrate participate in the expansion process at local scale. Through laboratory experiments, we demonstrated that the seeds of O. drummondii can be dispersed by seawater, since 0.63% present both buoyancy in seawater and subsequent germination after being washed with fresh water. This capacity for dispersal by marine currents could explain both the expansion of the species along the southwestern coast of Spain and the maintenance of its populations following disturbances such as storms. We also demonstrated that Iberian Hares and European Rabbits can disperse the seeds by endozoochory; seeds recovered from faecal pellets of these species were capable of germination (73 and 63%, respectively). Oenothera drummondii has become an invader only in coastal dunes where these dispersers are present, and with no control actions to regulate their populations. In conclusion, O. drummondii is an alien species with varying dispersal methods, polychory. This helps maintain already established populations and disperses seeds at a regional level, depending on the incidence of storms and the presence or absence of rabbits and hares for efficient local seed dispersion. Thus, management actions that restrict marine and animal dispersal likely have the benefit of limiting the invasive potential of O. drummondii.Consejo Nacional de Ciencia y Tecnología (CONACYT) 7799Ministerio de Economía y Competitividad CGL2015-65058-

Genetic Variability of Mountain Pine (Pinus hartwegii Lindl) in the Protection of Flora and Fauna Area Nevado de Toluca

Mountain pine (Pinus hartwegii Lindl) is one of the most abundant conifers in the Protection of Flora and Fauna Area Nevado de Toluca in central Mexico; this natural protected area is threatened by urbanization; this has been manifested in forest health; there has been an increase in forest parasites like bark beetles and dwarf mistletoes, making necessary improve forest management and conservation, hence our objective was to study the genetic diversity of mountain pine under the attack of parasites and to generate information that could be used to improve strategies of conservation of these forests. We classified sampled trees into four categories according to the type of parasite present in a tree (bark beetle: BB; dwarf mistletoe: DM; bark beetle and dwarf mistletoe: BM and non-attacked trees or healthy trees: HT). Genetic diversity was low in comparison with other pine species, but we observed an interesting issue: trees attacked by bark beetle and dwarf mistletoe had higher levels of heterozygosis: Henc = 0.1924 and Henc = 0.1993, respectively. These results suggest that trees with bark beetle and dwarf mistletoes may have higher genetic variability and are a highly valuable genetic resource for mountain pine