Some aspects of upwelling in the Gulf of Panama

ENGLISH: Strong coastal upwelling occurs in the Gulf of Panama regularly each year during the season, from about January through April, when strong northerly winds are blowing offshore. Because of the evident importance of upwelling to the ecology of the Gulf of Panama, we commenced in the fall of 1954 a study of various physical, chemical, and biological phenomena associated therewith. Observations were taken at bi-weekly intervals at a fixed location in the Gulf (approximately 10 miles SE of Taboga Island) to supplement the serial observations of sea level, sea temperature, and winds that have been gathered for many years by the Panama Canal Company. SPANISH: Cado año, en la estación de enero a abril, cuando los vientos del norte soplan vigorosamente frente a la costa, ocurre en el Golfo de Panamá un fuerte afloramiento costanero. Se cree que este afloramiento periódico en el Golfo de Panamá es responsable de la alta productividad biológica que sostiene considerables cantidades de organismos de importancia comercial. Esta región, por ejemplo, es una fuente importante de la especie Cetengraulis mysticetus) pez de carnada para el atún, (Alverson y Shimada, 1957) y mantiene una considerable pesca de camarones llamados langostinos (Burkenroad, Obarrio y Mendoza,1955). (PDF contains 54 pages.

Arsenic mitigation: water quality of dug wells and tubewells

Arsenic concentration in very shallow and deep aquifers is comparatively lower than shallow aquifers in arsenic contaminated areas. As a result, dug wells and deep tubewells have emerged as two major water supply options for populations exposed to high levels of arsenic through drinking contaminated shallow tubewell water in Bangladesh and West Bengal (India). The concentrations of other impurities of health concern also vary with depth and other characteristics of the aquifer. Hence, shifting from one source to another may be the cause of exposure to health risk of a different nature. This paper presents an assessment of water quality of dug wells (DW) and deep tubewells (DTW) as compared to shallow tubewells (STW) for water supply. The results show that a shift from STW to DW reduces median arsenic ingestion from 151 μg/L (Mean 172μg/L) to 0.74 μg/L(mean 7.92μg/L), while DTW further reduces median arsenic ingestion to 0.41μg/L (mean 1.05μg/L). On the other hand, microbial contamination indicated by median value of Thermotolerant Coliform (TTC) count was found to be 48 cfu/100ml for DW water as compared to 0 cfu/100ml for both STW and DTW waters

A radium assay technique using hydrous titanium oxide adsorbent for the Sudbury Neutrino Observatory

As photodisintegration of deuterons mimics the disintegration of deuterons by neutrinos, the accurate measurement of the radioactivity from thorium and uranium decay chains in the heavy water in the Sudbury Neutrino Observatory (SNO) is essential for the determination of the total solar neutrino flux. A radium assay technique of the required sensitivity is described that uses hydrous titanium oxide adsorbent on a filtration membrane together with a beta-alpha delayed coincidence counting system. For a 200 tonne assay the detection limit for 232Th is a concentration of 3 x 10^(-16) g Th/g water and for 238U of 3 x 10^(-16) g U/g water. Results of assays of both the heavy and light water carried out during the first two years of data collection of SNO are presented.Comment: 12 pages, 4 figure

The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

Effects of rapeseed variety and oil extraction method on the content and ileal digestibility of crude protein and amino acids in rapeseed cake and softly processed rapeseed meal fed to broiler chickens

We examined the effects of rapeseed variety and oil extraction method on crude protein (CP) and amino acid (AA) content in rapeseed co-products, and determined their coefficient of apparent (AID) and standardised ileal digestibility (SID) in broiler chickens. Sixteen rapeseed samples were de-oiled; four were cold-pressed producing rapeseed cake (RSC) and twelve were mild processed and hexane-extracted producing soft rapeseed meal (SRSM). One batch of the variety Compass, grown on the same farm, was processed using both methods obtaining Compass RSC and Compass SRSM. DK Cabernet rapeseed variety, grown on three different farms, was used to produce two SRSM batches and one RSC batch. All rapeseed co-products were ground through a 4 mm screen and mixed into semi-synthetic diets at a level of 500 g/kg. Day-old Ross 308 male broilers were fed a commercial diet for 14 days. A total of 96 pairs of birds were then allotted to 1 of 16 dietary treatments (n = 6) and fed a test diet for 8 days. Birds were then culled allowing removal of ileal digesta from Meckel’s diverticulum to the ileal-caecal junction. Digestibility of CP and AA was determined using titanium dioxide as an inert marker. The SRSM samples had an increased content of CP (419–560 g/kg DM) compared to RSC samples (293–340 g/kg DM). Both AID and SID of lysine, and SID of arginine, histidine and threonine were greater in Compass RSC compared to its SRSM counterpart (P 0.05). The SID of lysine was on average 0.03 units greater (P < 0.001) in RSC than in SRSM. The SRSM produced from variety PR46W21 showed similar or greater AID and SID of individual AA than the RSC from four other rapeseed varieties. It is concluded that selection of rapeseed varieties, and extraction method have a potential to deliver high-protein dietary ingredients with a good digestibility value

Genetic characterisation of Escherichia coli RecN protein as a member of SMC family of proteins

YesThe proteins of SMC family are characterised by having Walker A and B sites. The Escherichia coli RecN protein is a prokaryotic member of SMC family that involved in the induced excision of Tn10 and the repair of the DNA double strand breaks. In this work, the Walker A nucleotide binding site of the E. coli RecN protein was mutated by changing the highly conserved lysine residue 35 to the aspartic acid (D), designated as recN(K35D). Reverse genetics was utilized to delete the entire recN gene (Delta recN108) or introduce the recN(K35D) gene into the E. coli chromosomal DNA. The recN(K35D) cells showed decreasing in the frequency of excision of Tn10 from gal7

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results