Artificial light pollution influences behavioral and physiological traits in a keystone predator species, Concholepas concholepas

Artificial Light At Night (ALAN) is an increasing global problem that, despite being widely recognized in terrestrial systems, has been studied much less in marine habitats. In this study we investigated the effect of ALAN on behavioral and physiological traits of Concholepas concholepas, an important keystone species of the south-eastern Pacific coast. We used juveniles collected in intertidal habitats that had not previously been exposed to ALAN. In the laboratory we exposed them to two treatments: darkness and white LED (Lighting Emitting Diodes) to test for the impacts of ALAN on prey-searching behavior, self-righting time and metabolism. In the field, the distribution of juveniles was observed during daylight-hours to determine whether C. concholepas preferred shaded or illuminated microhabitats. Moreover, we compared the abundance of juveniles collected during day- and night-time hours. The laboratory experiments demonstrated that juveniles of C. concholepas seek out and choose their prey more efficiently in darkened areas. White LED illuminated conditions increased righting times and metabolism. Field surveys indicated that, during daylight hours, juveniles were more abundant in shaded micro-habitats than in illuminated ones. However, during darkness hours, individuals were not seen to aggregate in any particular microhabitats. We conclude that the exposure to ALAN might disrupt important behavioral and physiological traits of small juveniles in this species which, as a mechanism to avoid visual predators, are mainly active at night. It follows that ALAN in coastal areas might modify the entire community structure of intertidal habitats by altering the behavior of this keystone species

Influence of Wheat Straw Pelletizing and Inclusion Rate in Dry Rolled or Steam-flaked Corn-based Finishing Diets on Characteristics of Digestion for Feedlot Cattle.

Eight Holstein steers (216±48 kg body weight) fitted with ruminal and duodenal cannulas were used to evaluate effects of wheat straw processing (ground vs pelleted) at two straw inclusion rates (7% and 14%; dry matter basis) in dry rolled or steam-flaked corn-based finishing diets on characteristics of digestion. The experimental design was a split plot consisting of two simultaneous 4×4 Latin squares. Increasing straw level reduced ruminal (p<0.01) and total tract (p = 0.03) organic matter (OM) digestion. As expected, increasing wheat straw level from 7% to 14% decreased (p<0.05) ruminal and total tract digestion of OM. Digestion of neutral detergent fiber (NDF) and starch, per se, were not affected (p>0.10) by wheat straw level. Likewise, straw level did not influence ruminal acetate and propionate molar proportions or estimated methane production (p>0.10). Pelleting straw did not affect (p≥0.48) ruminal digestion of OM, NDF, and starch, or microbial efficiency. Ruminal feed N digestion was greater (7.4%; p = 0.02) for ground than for pelleted wheat straw diets. Although ruminal starch digestion was not affected by straw processing, post-ruminal (p<0.01), and total-tract starch (p = 0.05) digestion were greater for ground than for pelleted wheat straw diets, resulting in a tendency for increased post-ruminal (p = 0.06) and total tract (p = 0.07) OM digestion. Pelleting wheat straw decreased (p<0.01) ruminal pH, although ruminal volatile fatty acids (VFA) concentration and estimated methane were not affected (p≥0.27). Ruminal digestion of OM and starch, and post-ruminal and total tract digestion of OM, starch and N were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal NDF digestion was greater (p = 0.02) for dry rolled than for steam-flaked corn, although total tract NDF digestion was unaffected (p = 0.94). Ruminal microbial efficiency and ruminal degradation of feed N were not affected (p>0.14) by corn processing. However, microbial N flow to the small intestine and ruminal N efficiency (non-ammonia N flow to the small intestine/N intake) were greater (p<0.01) for steam-flaked than for dry rolled corn-based diets. Ruminal pH and total VFA concentration were not affected (p≥ 0.16) by corn processing method. Compared with dry rolled corn, steam-flaked corn-based diets resulted in decreased acetate:propionate molar ratio (p = 0.02). It is concluded that at 7% or 14% straw inclusion rate, changes in physical characteristics of wheat straw brought about by pelleting negatively impact OM digestion of both steam-flaked and dry-rolled corn-based finishing diets. This effect is due to decreased post-ruminal starch digestion. Replacement of ground straw with pelleted straw also may decrease ruminal pH

Synthesis, characterization of a new carbonylated zirconium metallocene using a dichloro-zirconocene derived from partially alkylated s-indacene

Indexación: ScieloThis work describes the synthesis and characterization of new organometallic species, an unprecedented mononuclear zirconium complex bearing a tetraalkylated s-indacene ligand, and secondly, its respective dicarbonyl complex obtained by reduction with Mg/HgCl2. Theoretical calculations of these two compounds were carried out to gain further understanding of these novel molecular systems.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072009000300014&lng=es&nrm=is

Influence of Feeding Enzymatically Hydrolyzed Yeast Cell Wall on Growth Performance and Digestive Function of Feedlot Cattle during Periods of Elevated Ambient Temperature.

In experiment 1, eighty crossbred steers (239±15 kg) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers (292±5 kg) with cannulas in the rumen and proximal duodenum were used in a 4×4 Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets

Hyphomycetes Acuáticos en Chile: estudio en el Estero de Limache; un afluente del Río Aconcagua

Mediante toma de muestras seriadas efectuadas en el transcurso de un año, se estudia la presencia de Hyphomycetes acuáticos aplicando la técnica de filtrado de las aguas según el método de lqbal y Webster (1973).Se contabilizaron los conidios de hongos acuáticos y algunos terrestres, junto a las diatomeas retenidas en los filtros, analizando cualitativa y cuantitativamente los resultados con algunas variables del medio ambiente tales como: Oxígeno disuelto, Nitratos, Amonios, Temperatura, Pluviosidad y efectos estacionales.Se detectaron formas conidiales correspondientes a 13 géneros y 20 especies de Hyphomycetes acuáticos. Las especies dominantes fueron: Alatospora acuminata lngold, Flagellospora penicillioides lngold, Tetracladium marchalianum de Wild, Trisc       ophorus monosporus lngold y Triscelophorus sp. C

Generación de estados superficiales durante la formación electroforética catódica de películas de TiO2 sobre ito

In the present work TiO2 films were formed over Indium Tin Oxide (ITO) employing cathodic electrophoretic deposition (Cathodic-EPD) and Dr. Blade Technique. The films were characterized by electrochemical techniques in order to compare their electronic properties; as well as, their photoelectrochemical behavior. The electrochemical performance showed by the films, allowed to relate the modification occurring during the Cathodic-EPD, with the partial reduction of TiO2 nanoparticles, generating Ti3+ defects. These trapping states are modifying the electronic properties of the film, and diminishing the transport of the photoelectrogenerated electrons toward ITO

Calidad de vida y función sexual en mujeres con disfunción del piso-pélvico del sur de Chile

Antecedentes/Objetivos: La disfunción del piso pélvico (DPP) es muy prevalente, afectando a un tercio de las mujeres adultas. Estas patologías no suponen un riesgo vital, pero sus síntomas pueden interferir con las actividades de la vida diaria incluyendo aspectos físicos, sociales y sexuales. En el sur de Chile, en el Hospital de alta complejidad (Regional-Concepción), se ha implementado la Unidad de Piso Pélvico (UPP). No hay evidencia sobre el efecto que supone en la calidad de vida y la función sexual de las mujeres que la padecen Describir la calidad de vida y función sexual de mujeres controladas en la Unidad de Piso Pélvico de un Hospital de alta complejidad en Chile. Métodos: Estudio transversal. Población: usuarias con DPP de la UPP del H. Regional-Concepción. Muestra 173. Variables: Caract. sociodemográficas, antecedentes obstétricos, tipo de DPP, Variables de Calidad de Vida (percepción del estado de salud, limitación emocional, limitación de actividades cotidianas, alteraciones de actividades sociales) (Short Form-12 Health Survey) y función sexual (PISQ-12). Análisis: medidas de dispersión, frecuencia absoluta- relativa. Resultados: Edad media 57 años, 88% con ingreso menor a 357€. 91% con IMC-sobrepeso y obesidad, 64% ≥ 3 hijos. Tipos DPP: 53% incontinencia de orina (IO), 35% prolapso vaginal (Pp), 12% IO+Pp. Calidad de vida (n = 173): Mala percepción de salud: 95%. Limitación emocional: 37%. Limitación de actividades cotidianas: 67%. Alteraciones de actividades sociales: 57% Función sexual (n = 95): Disfunción alta: 8,4%, moderada: 41,1%, baja 50,5%. El 15% nunca tuvo deseo-sexual los últimos 6 meses. El 14% admite no haber alcanzado el orgasmo en los últimos 6 meses, el mismo porcentaje admite no sentir excitación en el mismo período. El 19% admite no estar satisfechas con las actividades sexuales actuales, el 15% siente dolor durante las relaciones sexuales, el 40% admite sufrir de pérdidas de orina durante la actividad sexual, y el mismo número admite restringir su vida sexual debido al miedo de pérdida de orina durante el acto sexual. El 27% admite tener reacciones emocionales negativas durante las relaciones sexuales. El 10% y el 13% admite que sus parejas sufrían de disfunción eréctil y eyaculación, respectivamente. Por último, el 42% de las mujeres admite que sus orgasmos en los últimos 6 meses son más intensos. Conclusiones: Las mujeres con DPP presentan una alteración negativa de su calidad de vida y de su función sexual, aunque existe cierta incongruencia al valorar positivamente la calidad de los orgasmos cuando los demás aspectos de la vida sexual son negativos

Ocean Acidification Disrupts Prey Responses to Predator Cues but Not Net Prey Shell Growth in Concholepas concholepas (loco)

Background Most research on Ocean Acidification (OA) has largely focused on the process of calcification and the physiological trade-offs employed by calcifying organisms to support the building of calcium carbonate structures. However, there is growing evidence that OA can also impact upon other key biological processes such as survival, growth and behaviour. On wave-swept rocky shores the ability of gastropods to self-right after dislodgement, and rapidly return to normal orientation, reduces the risk of predation. Methodology/Principal Findings The impacts of OA on this self-righting behaviour and other important parameters such as growth, survival, shell dissolution and shell deposition in Concholepas concholepas (loco) were investigated under contrasting pCO2 levels. Although no impacts of OA on either growth or net shell calcification were found, the results did show that OA can significantly affect self-righting behaviour during the early ontogeny of this species with significantly faster righting times recorded for individuals of C. concholepas reared under increased average pCO2 concentrations (± SE) (716±12 and 1036±14 µatm CO2) compared to those reared at concentrations equivalent to those presently found in the surface ocean (388±8 µatm CO2). When loco were also exposed to the predatory crab Acanthocyclus hassleri, righting times were again increased by exposure to elevated CO2, although self-righting times were generally twice as fast as those observed in the absence of the crab. Conclusions and Significance These results suggest that self-righting in the early ontogeny of C. concholepas will be positively affected by pCO2 levels expected by the end of the 21st century and beginning of the next one. However, as the rate of self-righting is an adaptive trait evolved to reduce lethal predatory attacks, our result also suggest that OA may disrupt prey responses to predators in nature

Triple-Decker [Cp*Fe(C8H6)Fe(C8H7)]

The title compound [2(1,2,3,3a,6a-ƞ)pentalene]-[l(ƞ5)-pentamethylcyclopentadienyl]diiron, [Fe2(C8H7)-(C10H15)(C8H6)], has a metallocenic structure with the two pentalene ligands adopting an eclipsed conformation. In the central pentalene ligand, all the peripheral bonds are of similar length whereas the bridge bond is longer; there are two significantly different Fe-C distances, i.e. a mean value of 2.121(3)A for the Fe-Cbridge distances and a mean value of 2.028(3)A for the distances from the Fe atoms to all other Catoms. In the terminal pentalene ligand, the C-C and C-Fe distances in the ring bonded to the Fe atom are all similar