Technical note: The effects of five different defaunation methods on biogeochemical properties of intertidal sediment

Various methods have been used to remove organisms from sediments to investigate structure and function of faunal assemblages in intertidal habitats. Nevertheless, little is known about how these treatments affect properties of the sediments themselves, although changing these properties may cause changes in the assemblages, independently of other hypotheses being tested. This study assesses the efficacy of defaunation and effect on selected biogeochemical properties of five different methods of defaunating soft muddy sediments in an estuary. The methods were removal and freezing of sediment, removal and oven-heating, freezing in situ with liquid N2, spraying with formalin and spraying with hydrogen peroxide. The first four of these methods have been used in previous studies, whilst the fifth was considered to be a potentially useful defaunator because it does not leave toxic residues. The first two methods required sediment to be brought back to the lab, disrupting the natural structure of the sediment; the last three were done in situ, with much less disturbance.  Variables measured to assess effects of the treatments on the sediment were amount of water, grain size, total carbohydrate, suspension index (relative erosion rate), erosion threshold, chlorophyll a and b, colloidal carbohydrate, Fo (minimal fluorescence) and Fv/ Fm (photosynthetic yield). There were no significant effects of any treatment on the first four variables. For the others, effects of defaunation varied from treatment to treatment and with time after treatment. Generally, the greatest disturbance was to the microphytobenthos (MPB, measured by chlorophyll and fluorescence) and related variables. For most treatments, recovery was rapid, but the effects of formalin and H2O2 persisted for a few days. Effects on physical properties of the sediment were mostly minor and insignificant. Removal and freezing or heating, however, caused major changes to the sediments because of the disturbances involved. Choosing the appropriate method of defaunation is very important if interpretations are not to be confounded between the effects of defaunation per se and any effects of changes to other biota (such as microphytobenthos) and/or the properties of sediments caused by the method used to defaunate experimental areas

An effective lagrangian description of charged Higgs decays H^+ -> Wg, WZ and Wh

Charged Higgs decays are discussed within an effective lagrangian extension of the two-higgs doublet model, assuming new physics appearing in the Higgs sector of this model. Low energy constrains are used to imposse bounds on certain dimension -six operators that describe the modified charged Higgs interactions. These bounds are used then to study the decays H^+ -> Wg, WZ and Wh, which can have branching ratios of order 10^-5, 10^-1 and O(1), respectively; thse modes are thus sensitive probes of the symmetries of the Higgs sector that could be tested at future colliders.Comment: 15 pages, 3 figure

El sistema caprino extensivo en la sierra norte y este de Jaén, como base del desarrollo sostenible

En los quince municipios de menos de 5000 habitantes, localizados en el Parque Natural de Cazorla, Segura y Las Villas se ha puesto de manifiesto un proceso de despoblación, envejecimiento y empobrecimiento. La desaparición del mundo rural es un indicador de la degradación medioambiental. El presente trabajo pretende valorar técnica y económicamente el sector caprino de este parque natural, así como su nivel de competencia con el bosque mediterráneo. El estudio se centra en una muestra representativa de las explotaciones de caprino autóctono extensivo del parque natural, constituida por 63 rebaños, que representan el 60 p.100 del total de explotaciones La dimensión media de las explotaciones es de 213 cabras, con una UTH dedicada al caprino y dos por granja. El sistema productivo es eminentemente pastoril, de carácter familiar, con razas autóctonas muy adaptadas, pastos comunales y un régimen característico de pacería, denominado costeo y con unos canales de comercialización ineficientes. El ganado caprino (sin contabilizar el ovino y el vacuno) permite facturar por término medio 1.800.000 pta y generar un flujo de caja en torno a las 300.000 pta al año. Los valores de carga (0,78 UO por ha) están en consonancia con la capacidad sustentadora del parque entre 0,31 y 0,92 UO por ha (Gallego et al., 1991) y son inferiores a lo manifestados por Fernández Rebollo (1995). Además de la importancia económica y social del sistema productivo de carácter sustentable, se ha de tener presente que los protagonistas del desarrollo sostenible son los habitantes del medio rural y estos han de participar la adopción de decisiones

Estrategia de enseñanza y aprendizaje para el estudio de los elementos característicos de la parábola

El presente trabajo da cuenta de una estrategia didáctica para innovar el anquilosado proceso de enseñanza-aprendizaje de la parábola, en el Bachillerato General José Clemente Orozco de Tehuacán, Puebla, México. La propuesta está estructurada con diferentes actividades que se desarrollan en dieciséis sesiones-hora clase de 60 minutos cada una. Los resultados obtenidos en cada actividad muestran el proceso gradual del aprendizaje. Finalmente, se acota que los estudiantes aplicaron los conocimientos adquiridos en la construcción de una cocina parabólica solar y en este trabajo se muestran también las evidencias del funcionamiento eficiente y eficaz de la propositio

Influencia de la marcha en la biomecánica del clavo de Grosse-Kempf

El objetivo de este estudio ha sido conocer la influencia que tiene la deambulación en carga en la posibilidad de rotura del clavo centromedular encerrojado de fémur tipo Grosse- Kempf. El estudio ha consistido en 2 partes: en primer lugar se realiza un estudio estático-lineal del clavo mediante un programa de elementos finitos aplicándole las diferentes fuerzas que el clavo debe de soportar durante la marcha para conocer qué tipo de fuerzas son las que más afectan a su estructura; en segundo lugar hemos llevado a cabo un estudio cinemático-tridimensional de la marcha observando en qué fases de la misma se producen este tipo de fuerzas. Las fuerzas que más afectan al clavo son las de torsión, y el momento en que mayor fuerzas de este tipo se transmiten al clavo durante la marcha es al realizar el apoyo de la extremidad fracturada mientras la extremidad sana se encuentra en el aire. Como conclusión, no debe permitirse la deambulación total en carga en pacientes con el clavo colocado en estático ya que se corre un riesgo innecesario de rotura de material.This study was aimed at knowing the influence of gait with total weight bearing on the possibility of breakage of the Grosse-Kempf's locked femoral nail. The study consisted of two parts: firstly, we carry out a static linear study of the nail by means of a finite element method applying the different forces that the nail support during gait in order to know what type of forces affect more the structure.; secondly a kinematic-tridimensional study of gait was performed showing the phases in which the implant was more affected for different forces. Torsion forces specially at the single lines support phase during gait are the forces inducing the major stress at the implant. As conclusion, total weight bearing showed not be permited in patients with insufficient cortical support or static locking since there is an increase in the risk of breakage of the nail

Tests of Higgs and Top Effective Interactions

We study the possibility to detect heavy physics effects in the interactions of Higgs bosons and the top quark at future colliders using the effective Lagrangian approach. The modification of the interactions may enhance the production of Higgs bosons at hadron colliders through the mechanisms of gluon fusion and associated production with a W boson or $t\bar{t}$ pairs. The most promising signature is through the decay of the Higgs boson into two photons, whose branching ratio is also enhanced in this approach. As a consequence of our analysis we get a bound on the chromomagnetic dipole moment of the top quark.Comment: 14 pages, Latex, two figures available by fax under request. To be published in Phys. Lett

Simulating spin systems on IANUS, an FPGA-based computer

We describe the hardwired implementation of algorithms for Monte Carlo simulations of a large class of spin models. We have implemented these algorithms as VHDL codes and we have mapped them onto a dedicated processor based on a large FPGA device. The measured performance on one such processor is comparable to O(100) carefully programmed high-end PCs: it turns out to be even better for some selected spin models. We describe here codes that we are currently executing on the IANUS massively parallel FPGA-based system.Comment: 19 pages, 8 figures; submitted to Computer Physics Communication

Changes in cannabinoid receptor binding and mRNA levels in several brain regions of aged rats

AbstractWe have recently found that cannabinoid receptor binding and gene expression markedly decreased in extrapyramidal structures of aged rats. The present study was designed to analyze the possible existence of similar aging-induced changes in cannabinoid receptor binding and gene expression in brain regions other than extrapyramidal areas, but that also contain a significant population of cannabinoid receptors, such as the cerebellum, hippocampal structures, limbic and hypothalamic nuclei, the cerebral cortex and others. To this end, we analyzed cannabinoid receptor binding, using autoradiography, and cannabinoid receptor mRNA levels, using in situ hybridization, in slide-mounted brain sections obtained from young (3 month old) and aged (>2 year old) rats. Results were as follows. In the cerebellum, aged rats exhibited a marked decrease in cannabinoid receptor binding in the molecular layer (−33.3%), although accompanied by no changes in mRNA levels in the granular layer. In the cerebral cortex, a small, although statistically significant, decrease in binding was found in the deep layer (VI) (−18.3%) of aged rats, whereas no changes were found in the superficial layer (I). As in the case of the cerebellum, mRNA levels did not change in the cerebral cortex layers (II–III and V–VI). The different regions of the Ammon’s horn of the hippocampus exhibited similar cannabinoid receptor binding levels in aged and young rats. Interestingly, mRNA levels decreased in aged rats to a small, but statistically significant, extent (CA1: −26.1%; CA2: −21.6%; CA3: −14.4%). This was also seen in another hippocampal structure, the dentate gyrus (−14.6%), although in this region binding levels increased in aged rats (+28.4%). Two hypothalamic structures, the arcuate nucleus and the ventromedial hypothalamic nucleus, exhibited decreased cannabinoid receptor binding in aged rats (−31.1% and −30.3%, respectively), but this was not seen in the medial preoptic area. This was accompanied by no changes in mRNA levels in the ventromedial hypothalamic nucleus. In the limbic structures, aged rats exhibited similar binding levels to young rats. This was seen in the nucleus accumbens, septum nuclei and basolateral amygdaloid nucleus. However, mRNA levels slightly decreased in the basolateral amygdaloid nucleus (−13.4%), whereas they were not altered in the septum nuclei. Finally, other brain structures, such as the central gray substance and the brainstem, exhibited similar binding levels in aged and young rats. However, it is important to note that mRNA levels increased significantly (+211.2%) in the brainstem of aged rats, an area where the levels of binding and mRNA were very low in young rats. This marked increase may be related to an increase in the presence of glial elements in this region, as revealed by the increase in the immunoreactivity for glial fibrillary acidic protein observed in the brainstem of aged rats as compared to young animals. In summary, senescence was associated with changes in cannabinoid receptors in the cerebellum, the cerebral cortex, limbic and hypothalamic structures, the hippocampus and other brain regions. However, the changes observed (i) were not as marked and relevant as those early reported in extrapyramidal areas, and (ii) exhibited regional differences that might be attributed to the different roles played by these receptors in each region. Of particular relevance by their magnitude were the aging-induced decrease in binding found in the cerebellum and the hypothalamus, and the increase in mRNA levels observed in the brainstem. The latter might be related to an increase in the presence of glial cells which might contain cannabinoid receptor mRNA

SEOM clinical guidelines for the treatment of head and neck cancer (2017)

Head and neck cancer (HNC) is defined as malignant tumours located in the upper aerodigestive tract and represents 5% of oncologic cases in adults in Spain. More than 90% of these tumours have squamous histology. In an effort to incorporate evidence obtained since 2013 publication, Spanish Society of Medical Oncology (SEOM) presents an update of HNC diagnosis and treatment guideline. The eighth edition of TNM classification, published in January 2017, introduces important changes for p16-positive oropharyngeal tumours, for lip and oral cavity cancer and for N3 category. In addition, there are new data about induction chemotherapy and the role of immunotherapy in HNC

Integrated results and policy implications

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