1,996 research outputs found

    Reply to `Comment on ``Helmholtz Theorem and the V-Gauge in the Problem of Superluminal and Instantaneous Signals in Classical Electrodynamics" by A. Chubykalo Et Al' by J. A. Heras [FOUND. Phys. Lett. vol. 19(6) p. 579 (2006)]

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    This is the reply to `COMMENT ON ``HELMHOLTZ THEOREM AND THE V-GAUGE IN THE PROBLEM OF SUPERLUMINAL AND INSTANTANEOUS SIGNALS IN CLASSICAL ELECTRODYNAMICS" BY A. CHUBYKALO ET AL' BY J. A. HERAS [FOUND. PHYS. LETT. vol. 19(6) p. 579 (2006)]Comment: 5 pages, submitted to Foundations of Physic

    Data report: early Pleistocene calcareous nannofossils, IODP Expedition 339, Site U1387

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    We present a revision and refinement of semiquantitative analyses of calcareous nannofossil assemblages in early Pleistocene samples from Holes U1387A and U1387C recovered toward the eastern end of the Faro Drift (36°48.3210N, 7°43.1321W) during Integrated Ocean Drilling Program Expedition 339, Mediterranean Outflow (November 2011–January 2012). The record is characterized by intervals very rich in calcareous nannofossils that are in general moderately to well preserved. On the other hand, the record contains an interval directly above the youngest dolomite layer in Section 339-U1387C-19R-4 (~0.7 m) where no coccoliths were preserved. The new stratigraphic constraints of events such as the lowest occurrence (LO) of large Gephyrocapsa, the highest occurrence (HO) of Calcidiscus macintyrei (1.66 Ma), the LO of medium-sized Gephyrocapsa group, and the HO of Discoaster brouweri (1.95 Ma) allow better interpretation of the isotope stratigraphy applied to this interval.FCT Portugal projects CCMAR:UID/Multi/04326/2019info:eu-repo/semantics/publishedVersio

    Llama and Cattle Grazing Effects on Hydrological Function in a High-Elevation Mountain Rangeland

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    Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Producción AnimalThe impact of cattle versus llama grazing on hydrologic soil function was measured in poor and regular-condition high-elevation ecological sites, under deferred grazing system. A randomized, 2×2 factorial design with covariance was used, where the factors were animal species and rangeland condition, with repeated measures. Rangeland hydrology parameters were biomass, litter, soil bulk density, infiltration rate, and soil moisture. Results showed that following deferred grazing, there was more biomass and litter available in regular-condition paddocks, where hydric response was also better. Llama paddocks also had more biomass and litter and less soil compaction resulting in a greater infiltration rate than cattle paddocks. Further evaluation of the role of deferment and camelid grazing in maintaining and improving the hydrologic function of rangeland ecosystems is needed

    The Abad composite (SE Spain): a Messinian reference section for the Mediterranean and the APTS

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    A high-resolution integrated stratigraphy is presented for the Abad marls of the Sorbas and Nijar basins in SE Spain (preevaporitic Messinian of the Western Mediterranean). Detailed cyclostratigraphic and biostratigraphic analyses of partially overlapping subsections were needed to overcome stratigraphic problems in particular encountered at the complex transition from the Lower to the Upper Abad. The resulting Abad composite section contains a continuous stratigraphic record from the Tortonian/Messinian boundary up to the transition to the Messinian evaporites of the Yesares Member. All together, 18 calcareous plankton events were recognized which were shown to be synchronous throughout the Mediterranean by means of detailed (bed-to-bed) cyclostratigraphic correlations. The magnetostratigraphy allowed the identification of the four magnetic reversals of chron C3An in the Upper Abad. Details in the sedimentary cycle patterns allowed the Abad composite to be astronomically calibrated. This calibration to the 658N summer insolation curve of solution La90(1,1) yielded astronomical ages for all sedimentary cycles, calcareous plankton bioevents, ash layers and paleomagnetic reversals. Up to now, the Abad composite is the only astronomically well-calibrated section that provided a reliable cyclostratigraphy, magnetostratigraphy and calcareous plankton biostratigraphy. As such it will serve as a reference section both for the pre-evaporite Messinian in the Mediterranean as well as for the Messinian interval in the Astronomical Polarity Time Scale

    Intercalary membrane as the inner wall overlying optic and chorio-retinal colobomas. Deep penetration Swept Source-OCT study.

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    Five eyes of four patients were studied to analyze the structure of the inner wall of optic and chorioretinal colobomas using swept-source optical coherence tomography (SS-OCT). The colobomatous cavities and their relationship with adjacent structures were examined. SS-OCT permitted the study of the colobomatous cavities in all cases. In four of those cases, a Y-shaped intercalary membrane (ICM) was identified, with an origin in the retinal nerve fiber layer (RNFL), which covered the coloboma and in one case the coloboma was in contact with the vitreous cavity. Vitreous adhesion to the internal wall of the coloboma was found in three cases. No clinical or tomographic maculopathy was observed in any patient. High-resolution deep penetration SS-OCT allows in vivo study of optic and chorioretinal colobomas, identifying the RNFL as the main component of the ICM overlying the colobomatous cavities

    Impact of concurrent pregnancy and lactation on maternal nestbuilding, estradiol and progesterone concentrations in rabbits

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    [EN] We evaluated the impact of concurrent pregnancy and lactation on: nest-building (i.e., digging, straw-carrying, hair-pulling), food intake, milk output, body weight, and the concentration of estradiol and progesterone in blood. Digging was lower in pregnant-lactating (PL) rabbits, compared with pregnant-only (PO) does, on 21-23 d (52±64 vs. 104±86 g, respectively; mean±SD; P<0.05). Straw-carrying was also reduced in PL does on 24-26 d (9±27 vs. 79±94 g; P<0.005), 27-29 (27±56 vs. 99±77 g; P<0.005), and in the total amount of material introduced into the nest box (132±167 vs. 286±217 g; P<0.02). Hair-pulling was expressed by practically all animals. Food intake declined in PO does on the three days preceding parturition (P<0.01) and increased markedly during lactation; this increase was much larger in PL than in lactating-only (LO) rabbits (P<0.01). Milk output was similar between PL and LO does during the first 21 d of lactation but a marked decline in this parameter occurred in PL does from then until 30 d. The differences in nest-building between PL and PO rabbits may be related to the concentrations of estradiol and progesterone on specific days of pregnancy. PL does showed significantly higher estradiol levels than PO animals on pregnancy 1 d (33±13 vs. 23±4 pg/mL; P<0.02) and 21 (34±19 vs. 24±6 pg/mL; P<0.05) and also higher levels of progesterone on pregnancy 1 d (4±5 vs. 1±2 ng/mL; P<0.05). However, PL rabbits had lower levels of progesterone on 7 d (6±3 vs. 9±2 ng/mL; P<0.02) and 14 d (8±3 vs. 11±3 ng/mL; P<0.005) than PO does. Our results indicate that the unique endocrine milieu of PL rabbits has a direct bearing on specific behavioral and physiological phenomena that impact productivity on the farm.González-Mariscal, G.; Gallegos, J.; Sierra-Ramírez, A.; Garza Flores, J. (2009). Impact of concurrent pregnancy and lactation on maternal nestbuilding, estradiol and progesterone concentrations in rabbits. World Rabbit Science. 17(3):145-152. doi:10.4995/wrs.2009.65414515217

    Aerospace industry in Queretaro, Mexico: a perspective of regional innovation system

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    Using the theoretical perspective of the Regional Innovation System (RIS), this paper analyzes the structure of the aerospace industry in Mexico, focusing on the region of Querétaro, Mexico. The objective of the research is to analyze the development, growth prospects , key agents and their interrelations of the aerospace industry in the Queretaro region from the perspective of the RIS. The aerospace industry in Querétaro has more than 40 companies, research centers and universities, intermediate and government agencies that focus on the aerospace industry, the region has presented rates of economic growth above the national average in the last 6 years, however to achieve the consolidation of the aerospace industry towards an RIS requires greater efforts of articulation and coordination among the agents that make up the system, it can be achieved through strategies and policies in joint collaboration for the consolidation of the industry in the region.N/

    No-reproducing of Varroa jacobsoni in Apis mellifera iberica

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    We checked no-reproduction of Varroa jacobsoni in a honeybee race, Apis mellifera iberica. Two groups of three colonies from different apiaries located in Cazorla (Jaén) were checked. Only cells containing white pupa with red-brown eyes and a single mother mite were used. There were diferences between high and low parasitized groups, but only using natural data, not when we use percentages. Further experiments are necessary in order to know the source of these diferences.En este trabajo hemos chequeado la falta de éxito reproductivo del parásito Varroa jacobsoni Oud en dos grupos de colonias de la raza de abejas Apis mellifera iberica procedentes de dos colmenares de la Sierra de Cazorla. Cada grupo se encontraba formado por tres colonias. Celdillas de cría de abejas obreras en estado de pupas blancas con ojos pardos fueron desoperculadas, registrando si se encontraban parasitadas o no, y en aquellas parasitadas por una única varroa progenitora la falta de éxito reproductivo, entendiendo como tal la ausencia de descendientes o la presencia exclusiva de descendientes machos y/o protoninfas. La falta de éxito reproductivo fue superior en el grupo menos parasitado, aunque sólo se pudieron establecer diferencias significativas cuando trabajamos con los datos naturales, y no con los porcentajes
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