On the formation and physical properties of the Intra-Cluster Light in hierarchical galaxy formation models

We study the formation of the Intra-Cluster Light (ICL) using a semi-analytic model of galaxy formation, coupled to merger trees extracted from N-body simulations of groups and clusters. We assume that the ICL forms by (1) stellar stripping of satellite galaxies and (2) relaxation processes that take place during galaxy mergers. The fraction of ICL in groups and clusters predicted by our models ranges between 10 and 40 per cent, with a large halo-to-halo scatter and no halo mass dependence. We note, however, that our predicted ICL fractions depend on the resolution: for a set of simulations with particle mass one order of magnitude larger than that adopted in the high resolution runs used in our study, we find that the predicted ICL fractions are ~30-40 per cent larger than those found in the high resolution runs. On cluster scale, large part of the scatter is due to a range of dynamical histories, while on smaller scale it is driven by individual accretion events and stripping of very massive satellites, $M_{*} \gtrsim 10^{10.5} M_{\odot}$, that we find to be the major contributors to the ICL. The ICL in our models forms very late (below $z\sim 1$), and a fraction varying between 5 and 25 per cent of it has been accreted during the hierarchical growth of haloes. In agreement with recent observational measurements, we find the ICL to be made of stars covering a relatively large range of metallicity, with the bulk of them being sub-solar.Comment: Accepted for Publication in MNRAS, 19 pages, 13 figures, 1 tabl

Vector Mosquito Surveillance Using Centers For Disease Control and Prevention Autocidal Gravid Ovitraps In San Antonio, Texas

Mosquito surveillance in large urban areas of the southern USA that border Mexico has become increasingly important due to recent transmission of Zika virus and chikungunya virus in the Americas as well as the continued threat of dengue and West Nile viruses. The vectors of these viruses, Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus, co-occur in residential areas, requiring vector control entities to deploy several different trap types, often expensive and labor-intensive, to surveil these ecologically different species. We evaluated the use of a single trap type, the US Centers for Disease Control and Prevention autocidal gravid ovitraps (AGOs), to monitor all 3 vector species across residential neighborhoods in San Antonio, TX, over 12 wk (epiweeks 24–35). Mosquito abundance was highest early in our surveillance period (epiweek 25) and was driven largely by Cx. quinquefasciatus. The AGOs collected significantly more Cx. quinquefasciatus than both Aedes species, with more Ae. aegypti collected than Ae. albopictus. The average number of Ae. aegypti captured per trap was consistent across most neighborhoods except for 2 areas where one had significantly the highest and the other with the lowest mosquitoes collected per trap. The average number of Ae. albopictus captured per trap varied with no clear pattern, and Cx. quinquefasciatus were trapped most often near forested hill country neighborhoods. These results indicate that AGOs are appropriate for detecting and tracking the relative abundance of Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus across a large and diverse urban landscape over time and therefore may be an inexpensive and streamlined option for vector surveillance programs in large cities

Impacto de las Abejas (Apis mellifera L.) Como Agentes Polinizadores en el Rendimiento del Cultivo de Zucchini (Cucurbita pepo L.) en el Canton Riobamba, Provincia de Chimborazo

The impact of bees (Apis mellifera L.) as pollinators in the yield of the zucchini (Cucurbita pepo L.) crop in the Riobamba canton, Chimborazo province, was evaluated using a Randomized Complete Block Design (RCBD). This was done using three treatments and three repetitions. The treatments evaluated were: the zucchini cultivation inside the micro tunnel covered with entomological mesh with the presence of bees, the zucchini cultivation inside the micro tunnel covered with anti aphids mesh without the presence of bees, and the open field zucchini cultivation. The evaluated parameters were number of days to the appearance of the fruits, percentage of fertilized and unfertilized flowers, number of fruits per plant, size of fruits, diameter of fruits, weight of fruit, and yield in kg / ha per treatment. The best results achieved in most parametersthat were evaluated such as the percentage of flowering, number of fruits per plant, size of fruit in cm, diameter of fruit in cm, weight of the fruit in grams, yield in kg/ha by treatment, and economic analysis were obtained with the presence of bees (Apis mellifera L.) as pollinating agents in the tunnel. This is in addition to meshes during the flowering stage of the zucchini crop, with an average yield of 14.9 tn/ha.Se evaluó el impacto de las abejas (Apis mellifera L.) como agentes polinizadores en el rendimiento del cultivo de zucchini (Cucurbita pepo L.) en el cantòn Riobamba, provincia de Chimborazo. Para llevar a cabo esta evaluación se utilizó un diseño de bloques completos a azar (DBCA), con tres tratamientos y tres repeticiones. Los tratamientos evaluados fueron: El cultivo de zucchini dentro del micro túnel cubierto con malla entomológica con presencia de abejas, el cultivo de zucchini dentro del micro túnel cubierto con malla antiáfidossin presencia de abejas y el cultivo de zucchini a campo abierto. Los parámetros evaluados fueron número de días transcurridos después de la aparición de los frutos, porcentaje de flores fecundadas y no fecundadas, número de frutos por planta, tamaño de frutos, diámetro de frutos, peso del fruto y rendimiento en kg/ha por tratamiento. Los mejores resultados alcanzados en la mayoría de los parámetros evaluados como el porcentaje de floración, número de frutos por planta, tamaño de fruto en (cm), diámetro de fruto en (cm), peso del fruto en gramos, rendimiento en kg/ha por tratamiento y análisis económico, se obtuvieron con la presencia de las abejas (Apis mellifera L.) como agentes polinizadores en el túnel con mallas durante la etapa de floración del cultivo de zucchini, con un rendimiento en promedio de 14.9 tn/ha

Substrate Specificity of Organic Cation/H ϩ Exchange in Avian Renal Brush-Border Membranes

ABSTRACT The substrate specificity of the avian renal organic cation exchanger was examined in isolated renal brush-border membrane vesicles. Endobiotic and xenobiotic organic cations (OCs) were tested at a concentration of 100 M for cis-inhibition of 14 C-tetraethylammonium (TEA)/H ϩ exchange and at 1 mM for trans-stimulation of 14 C-TEA efflux. The xenobiotic cations amiloride, cimetidine, mepiperphenidol, procainamide, quinidine, quinine, and ranitidine cis-inhibited TEA uptake Ն 80%; isoproterenol and unlabeled TEA inhibited uptake at least 30%. In contrast, the endogenous cations acetylcholine, choline, and guanidine did not inhibit TEA uptake; however, epinephrine, N 1 -methylnicotinamide, serotonin, and thiamine inhibited uptake as much as 60%. Each endogenous cation, except thiamine, trans-stimulated TEA efflux, and xenobiotic cations, excluding isoproterenol and TEA, trans-inhibited TEA efflux. The data suggest that the avian renal tubule luminal OC exchanger has greater affinity for xenobiotic cations than for endobiotic cations, but greater transport capacity for endobiotics than for xenobiotics. The role of the "cation or hydrogen exchange mechanism" in the renal excretion of xenobiotic OCs was first proposed by Baer and colleagues Transport of OCs across the luminal membrane is of particular interest, as it is the rate-limiting step in the secretion of these compounds. Proton antiport is thought to be a primary means by which OCs are translocated across the luminal membrane. Although the existence of the luminal OC exchanger is well documented, the physiological role of this transporter in renal excretion of OCs, endobiotic OCs in particular, is not fully understood. Available data suggest that OC/H ϩ exchange may not be the sole means by which endobiotic OCs are transported across the luminal membrane. As demonstrated in rabbit BBMV, choline is poorly transported by the OC/H ϩ exchange mechanism, but is transported by electrogenic facilitated diffusion ABBREVIATIONS: OC, organic cation; TEA, tetraethylammonium; NMN, N 1 -methylnicotinamide; Darstine, mepiperphenidol; BBMV, brush-border membrane vesicle; K m , Michaelis constant; V max , maximal rate of uptake; V maxapp , apparent maximal rate of uptake; K mapp , apparent K m ; K i , calculated inhibitor constant; pK a , dissociation constant; M.W., molecular weight; T m , maximum tubular transport rate

Cryptic genetic subdivision in the San Benito evening primrose (Camissonia benitensis)

When rare plants are distributed across a range of habitats, ecotypic differentiation may arise requiring customized conservation measures. The rate of local adaptation may be accelerated in complex landscapes with numerous physical barriers to gene flow. In such cases, examining the distribution of genetic diversity is essential in determining conservation management units. We investigated the distribution of genetic diversity in the federally threatened Camissonia benitensis (Onagraceae), which grows in two distinct serpentine habitats across several watersheds in San Benito, Fresno, and Monterey Cos., CA, USA. We compared genetic diversity with that of its two widespread relatives, C. contorta and C. strigulosa, and examined the potential for hybridization with the latter species. Genotyping results using seven heterospecific microsatellite markers indicate that differentiation between habitat types was weak (F ST = 0.0433) and in an AMOVA analysis, there was no significant partitioning of molecular variation between habitats. Watersheds accounted for 11.6 % of the molecular variation (pairwise F ST = 0.1823–0.4275). Three cryptic genetic clusters were identified by InStruct and STRUCTURE that do not correlate with habitat or watershed. C. benitensis exhibits 5–11× higher inbreeding levels and 0.54× lower genetic diversity in comparison to its close relatives. We found no evidence of hybridization between C. benitensis and C. strigulosa. To maximize conservation of the limited amount of genetic diversity in C. benitensis, we recommend mixing seed representing the three cryptic genetic clusters across the species’ geographic range when establishing new populations

Descriptive morphology of the male genitalia in some neotropical species of the tribe Anaeini (LEPIDOPTERA, CHARAXIDAE)

Este artículo tiene la finalidad de demostrar la importancia taxonómica del estudio de los órganos genitales masculinos en mariposas neotropicales charaxinas de la tribu Anaeini. Se destacan y describen, además, algunos de los caracteres más relevantes de especies no consideradas en previos trabajos que son descritos gracias al extendido de las muestras, y que ayudarán a conocer mejor la identidad taxonómica en cuestión.This article aims to demonstrate the taxonomic importance of the study of male genital organs of Neotropical butterflies charaxins of tribe Aneini. Some of the most relevant characteristics of some species, not considered in previous and recent contributions, are described and highlighted thanks to the extension of the samples with the hope they will help to know better the taxonomic characteristics in question

Mating Ewes on Condensed Tannin-Containing Forages Increases Ewe Reproductive Rate and Reduces Lamb Mortality

Action of condensed tannin (CT) reduces forage protein degradation in the rumen and increases the absorption of amino acids from the small intestine (Barry & McNabb 1999). This paper reports the effects of grazing ewes on two CT-containing forages during mating upon ewe reproductive rate and lamb mortality

On extending actions of groups

Problems of dense and closed extension of actions of compact transformation groups are solved. The method developed in the paper is applied to problems of extension of equivariant maps and of construction of equivariant compactifications