Laboratory investigation of daily food intake and gut evacuation in larvae of African catfish Clarias gariepinus under different feeding conditions

Abstract Temporary accumulation of ascorbic acid 2-sulfate (AAS) was measured to estimate food intake and gut evacuation in larvae of African catfish. Fish larvae were fed decapsulated cysts of Artemia containing AAS. In a first experiment it was found that no biosynthesis of AAS occurs in the larvae of this species. In a second experiment, the gut contents of the fish larvae fed were calculated as they changed during development. In a third experiment, the gut evacuation rate of fish larvae was determined during continuous and discontinuous feeding regimes in the first five days after the start of exogenous feeding. Food consumption by catfish larvae increased from 46.5% of their body dry weight (BDW) on day 1 after the start of exogenous feeding to 53.8% BDW on day 3. Thereafter, food consumption decreased to 27.8% BDW on day 5. A similar pattern was observed for gut evacuation, which increased during the first days of exogenous feeding and decreased as fish growth continued. The rate of gut evacuation in a continuous feeding regime was significantly higher (P <0.05) than that under discontinuous feeding. On day 1 post-hatch and 7 h after first food ingestion the fish larvae evacuated 87% of the food in continuous feeding compared with 43% under discontinuous feeding. It was found that gut emptying differs during larval development. Under continuous feeding, on days 1 and 3 post-hatch and 11 h after the first meal 90% of the food was evacuated compared with 71% evacuated on day 5. The advantages and limitations of the AAS method for estimation of food consumption by fish larvae are discussed

The AgResults Nigeria Aflasafe TM Challenge Project: 2019 Annual Report

This report documents the key activities that were carried under the AgResults Aflasafe Pilot Project during the 2018/ 2019 maize-growing season on the verification process to trigger premium payments for successfully harvested and aggregated Aflasafe™-treated maize

A view of Large Magellanic Cloud HII regions N159, N132, and N166 through the 345 GHz window

We present results obtained towards the HII regions N159, N166, and N132 from the emission of several molecular lines in the 345 GHz window. Using ASTE we mapped a 2.4' $\times$ 2.4' region towards the molecular cloud N159-W in the $^{13}$CO J=3-2 line and observed several molecular lines at an IR peak very close to a massive young stellar object. $^{12}$CO and $^{13}$CO J=3-2 were observed towards two positions in N166 and one position in N132. The $^{13}$CO J=3-2 map of the N159-W cloud shows that the molecular peak is shifted southwest compared to the peak of the IR emission. Towards the IR peak we detected emission from HCN, HNC, HCO$^{+}$, C$_{2}$H J=4-3, CS J=7-6, and tentatively C$^{18}$O J=3-2. This is the first reported detection of these molecular lines in N159-W. The analysis of the C$_{2}$H line yields more evidence supporting that the chemistry involving this molecular species in compact and/or UCHII regions in the LMC should be similar to that in Galactic ones. A non-LTE study of the CO emission suggests the presence of both cool and warm gas in the analysed region. The same analysis for the CS, HCO$^{+}$, HCN, and HNC shows that it is very likely that their emissions arise mainly from warm gas with a density between $5 \times 10^5$ to some $10^6$ cm$^{-3}$. The obtained HCN/HNC abundance ratio greater than 1 is compatible with warm gas and with an star-forming scenario. From the analysis of the molecular lines observed towards N132 and N166 we propose that both regions should have similar physical conditions, with densities of about 10$^3$ cm$^{-3}$.Comment: accepted in MNRAS (October 5, 2015

Tunable entanglement distillation of spatially correlated down-converted photons

We report on a new technique for entanglement distillation of the bipartite continuous variable state of spatially correlated photons generated in the spontaneous parametric down-conversion process (SPDC), where tunable non-Gaussian operations are implemented and the post-processed entanglement is certified in real-time using a single-photon sensitive electron multiplying CCD (EMCCD) camera. The local operations are performed using non-Gaussian filters modulated into a programmable spatial light modulator and, by using the EMCCD camera for actively recording the probability distributions of the twin-photons, one has fine control of the Schmidt number of the distilled state. We show that even simple non-Gaussian filters can be finely tuned to a ~67% net gain of the initial entanglement generated in the SPDC process.Comment: 12 pages, 6 figure

Dipole formation at metal/PTCDA interfaces: Role of the Charge Neutrality Level

The formation of a metal/PTCDA (3, 4, 9, 10-perylenetetracarboxylic dianhydride) interface barrier is analyzed using weak-chemisorption theory. The electronic structure of the uncoupled PTCDA molecule and of the metal surface is calculated. Then, the induced density of interface states is obtained as a function of these two electronic structures and the interaction between both systems. This induced density of states is found to be large enough (even if the metal/PTCDA interaction is weak) for the definition of a Charge Neutrality Level for PTCDA, located 2.45 eV above the highest occupied molecular orbital. We conclude that the metal/PTCDA interface molecular level alignment is due to the electrostatic dipole created by the charge transfer between the two solids.Comment: 6 page

Estudio de línea base de comunidades: Informe de Análisis del sitio para Cauca – Los Cerrillos, Colombia (CO01)

Se presenta el informe del estudio de línea de base del TeSAC (Territorio Sostenible Adaptado al Clima) de la comunidad de Los Cerrillos, desarrollado entre 15 al 23 de noviembre de 2014 en el sitio CCAFS Cauca-Los Cerrillos (CO 01), Colombia. La cultura agrícola del monocultivo de café y caña ha generado una dependencia económica y de desarrollo que ante las crisis climáticas o de precios podría poner en peligro la seguridad alimentaria de la comunidad. La falta de diversificación de la producción y la generación de alternativas agro empresariales más rentables hace que los jóvenes inicien una migración a las ciudades poniendo en peligro la cultura rural del territorio. Aunque se nota un aumento en las coberturas boscosas la ausencia de la autoridad ambiental competente y el desconocimiento de estrategias para la conservación pone en peligro el mantenimiento de los bosques y la conservación de las aguas, en especial por la potencial amenaza de la minería a la cual la comunidad hasta ahora se ha opuesto. Durante los diferentes ejercicios se identificaron 38 organizaciones que desarrollan acciones en el territorio, de las cuales 23 se relacionan con seguridad alimentaria, 10 con crisis por alimentos y 18 en manejo de recursos naturales. Esto muestra que las crisis no han sido recurrentes, pero que existe una gran preocupación por la seguridad alimentaria y el manejo de los recursos naturales. Se resalta la importancia de tres organizaciones que son el eje de la articulación: Junta de Acción Comunal Los Cerrillos, Comité de Cafeteros del Cauca y la UMATA, que Dieciocho de las 19 organizaciones que operan en la comunidad se dedica a la seguridad alimentaria. No existen redes de información para la toma de sesiones agrícolas y climáticas, la comunidad culturalmente toma sus decisiones con base en señas de la naturaleza y consulta a los mayores, existe desconfianza de la información climática anunciada en la televisión. El ejercicio de visión de futuro permite notar el interés de la comunidad por mantener su tradición de agricultores, mejorar su infraestructura, cualificar la productividad y producción, conservar los recursos naturales, mejorar la equidad de género y prepararse para afrontar la variabilidad y cambio climático