Effect of cage density on growth and carcass performance of fattening rabbits under tropical heat stress conditions

[EN] Three hundred crossbred New Zealand, California, Butterfl y, Dutch, and Satin rabbits, weaned at 30 d and weighing 535±8 g (standard error) were assigned randomly to four treatments: 6, 12, 18 and 24 rabbits/m2 (3, 6, 9 and 12 rabbits/cage, respectively, each cage measuring 0.5 m2) resulting in 10 cages/treatment. During the experimental period (from weaning to 2.2 kg body weight) weekly individual live weight, cage feed intake, incidence of diarrhoea, ringworm, and injured rabbit data was recorded. The maximum temperature-humidity index ranged from 31 to 35, and so indicating severe heat stress. At the end of the experimental period 10, 20, 30 and 30 rabbits under densities of 6, 12, 18 and 24 rabbits/m2, respectively, were slaughtered and carcass performance recorded. Average daily gain and feed intake from weaning to the end of the experimental period decreased by 0.31±0.070 and 1.20±0.25 g, respectively, for each unit that the density increased at the beginning of the experiment (P=0.001). The length of the fattening period increased by 0.91±0.16 d (P=0.001) for each unit of increment of density. However, rabbit production (expressed in kg/m2) increased linearly and quadratically with density (P<0.008). Cage density did not affect feed effi ciency, which on average was 0.214 g/g (P=0.37). Animals housed at the highest density, compared to the average of those caged at lower densities, tended to show higher incidence of ringworm (68.9 vs 39.4%; P=0.075) and injury (16.8 vs 3.03%; P=0.12), and showed higher mortality (20.5 vs 9.63%; P=0.043). Density did not alter the dressing out percentage nor chilled carcass weight. The proportion of scapular fat (P=0.042) increased linearly with increasing levels of density, but perirrenal fat was unaffected (P=0.22). Increasing density reduced dorsal length linearly (P=0.001), and reduced drip loss percentage linearly and quadratically (P=0.097 and 0.018, respectively).Based on these results, under our heat stress conditions, avoiding densities higher than 18 rabbits/m2 or 34 kg/m2 at the end of fattening is recommended.Villalobos, O.; Guillén, O.; García J., J. (2010). Effect of cage density on growth and carcass performance of fattening rabbits under tropical heat stress conditions. World Rabbit Science. 16(2). doi:10.4995/wrs.2008.63116

The pitfalls of water potential for irrigation scheduling

The water potential (Ψp), has been widely used as an indicator of plant water status for irrigation management purposes. The simple infrastructure needed for its measurement and its direct relation to basic plant physiological processes, have contributed to the popularity of the methodology. When used for irrigation scheduling, it is commonly assumed that an unavoidable relationship exists between plant transpiration (T), soil water content and Ψp. Nevertheless, it is worth remembering that variations in Ψp are not solely related to changes in soil water content, but are also an expression of the interaction between the plant and its environment. We used a soil-plant-atmosphere-continuum (SPAC) model to highlight the importance of considering such interactions through a series of in silico experiments. Our analysis shows that evaporative demand, the hydraulic architecture of the plant, and the texture and depth of the soil play key roles in the final Ψp observed. To establish irrigation programs based on Ψp, without considering the environmental and plant factors that influence it, can create the paradox of having a plant that suffers greater water stress even when high irrigation volumes are applied. The conclusions from our in silico analysis provide some warnings that should be considered when using Ψp to schedule irrigation.info:eu-repo/semantics/publishedVersio

Studying and modelling winter dormancy in olive trees

The abundance of scientific papers dealing with olive reproductive phenology contrasts with the scarce information available in relation to the winter dormant state of olive vegetative structures. In this study, three experiments with young olive trees were performed in Southern Spain, aiming to provide insight into some features of the winter rest period in this evergreen species. Experiment 1 evaluated the environmental cues triggering dormancy induction by measuring leaf appearance rates in trees subjected to different conditions of temperature and daylength over the course of the 2012 autumn. In Experiment 2, several sets of plants were placed into a greenhouse at different dates along the 2013/2014 winter, testing the ability of dormant plants to resume growth upon the return of favourable temperatures. Finally, Experiment 3 was carried out during the autumns of 2016 and 2017 in two locations, and was devoted to assess differences between five cultivars in the onset of dormancy under natural conditions. Our findings revealed that dormancy induction is not controlled by photoperiod, but by low temperatures. The subsequent winter rest state seems to be easily reversed after 1–2 weeks of exposure to warm conditions, irrespective of the initial date of exposure. With regard to cultivar variability, differences in the timing of growth cessation was found to be rather small. Finally, two simple models for predicting the onset of dormancy based on the accumulation of a certain amount of chilling (either considering or not a reversal of chilling by warm temperatures) are presented. Calibration and validation was performed with independent datasets from Experiments 1, 2 and 3. Validation tests highlighted the reliability of both models in reproducing the date of growth cessation.info:eu-repo/semantics/acceptedVersio

Demonstration of membrane distillation on textile waste water: assessment of long term performance, membrane cleaning and waste heat integration

&copy; 2017 The Royal Society of Chemistry. This work reports outcomes of a pilot trial and practical assessment of direct contact membrane distillation (DCMD) towards achieving zero liquid discharge at a textile manufacturing plant. Treatment of textile wastewater is difficult due primarily to the complexity of textile processing and the wastewater produced. Combined effluent from the site, either untreated or treated with the site\u27s existing flocculation and biological processes, were considered as the feeds to the MD testing. Initial bench scale studies found rapid membrane wetting appeared to be avoided by the novel use of foam fractionation on the untreated effluent, or by using the conventionally treated effluent. The trial was conducted on treated effluent using fractionation on a side stream within the MD process, and no wetting was observed over the entire 3 month trial duration. The flux of the 6.4 m2 membrane module started at 5 L m-2 h-1 and declined to 2 L m-2 h-1 after more than 65 days. Caustic cleaning effectively restored flux to 4 L m-2 h-1. A 41-fold increase in feed concentration was verified by sulphate measurements, increasing from 567 mg L-1 to 23 000 mg L-1. After concentrating in the hot cycle, all ammonia entering the DCMD plant from the feedwater was found to evolve into the permeate, but non-volatile sulphate rejection was &gt;99.9%. Water recovery at the end of the trial was 91.6%. A plant integration assessment found that zero liquid discharge would be feasible if saline waste streams were isolated and reverse osmosis processes were coupled with MD harnessing waste heat. MD application to current and future treatment scenarios with waste heat integration to textile processing appears viable

Operational chain and techno-typological analysis of the prehistoric adornments of variscite from the center-south-west of the Spanish North Plateau. History of an artisan tradition

Los adornos de variscita son un tipo de artefacto empleado en distintos contextos de la Prehistoria reciente de buena parte de Europa Occidental y de forma general son interpretados como elementos de prestigio. El registro arqueológico del centro-sur-oeste de la Meseta Norte Española ofrece un caso de estudio ideal para reconstruir al completo su cadena operativa: 1) minería en Palazuelo de las Cuevas y otros lugares de la comarca de Aliste, 2) manufactura en los asentamientos de Quiruelas de Vidriales y en otros yacimientos y 3) consumo en una treintena de tumbas y poblados del Neolítico Final y el Calcolítico de las comarcas circundantes. Así, en este artículo se analizan las características tecno-tipológicas, escala y organización de la producción de adornos de variscita y sus continuidades y transformaciones con el paso del tiempo. Los resultados nos permiten hablar de una tradición artesana originada en el Neolítico Final la cual mantuvo sus rasgos tecno-tipológicos esenciales mientras crecieron la intensidad, la concentración y, probablemente, la especialización de su producción en el CalcolíticoDuring Late Prehistory adornments worked out of variscite are widely used as prestige items all over Europe. The archaeological record of centre-south-west Northern Spanish Meseta is an ideal case study to fully reconstruct the chaîné opératoire from 1. Mining at Aliste area (Palazuelo de las Cuevas and other nearby mines), 2. adornment manufacturing at the production locii of Quiruelas de Vidriales sites, 3. Adornment consumption in about 30 tombs and settlements from Late Neolithic to Copper Age in the nearby areas to the mining and manufacturing places. This paper analyses the technotypological features, scale and organisation of variscite adornment production patterns along time. Results allows to argue about a craft tradition born during the Late Neolithic that keep up its techno-tyopological features as grew up on intensity, concentration and most likely specialisation of the production during the Copper Ag

Efficacy of current treatments against hepatitis C virus

It is estimated that currently, in the world, approximately 3% of the population has chronic hepatitis, the hepatitis C virus is the etiological agent most related to the development of this pathology. The diversity of genotypes (7) and quasi-species of HCV, due to its high mutation rate, interferes with an effective humoral immunity. The aim of this work is precisely to evoke those usual drugs used in HCV therapy, as well as cutting-edge drugs. The goal of treatment is the eradication of HCV infection. One strategy offered by the WHO is to eradicate the virus in at-risk populations. Alternatives to the previously used treatment with interferon and ribavirin are shown in this paper; protease inhibitors and other targets have now been developed to make eradication of the virus more effective

Las aulas actuales: tecnología digital y discapacidad

La incorporación al aula de recursos y herramientas digitales plantea, además de cambios en el paradigma enseñanza-aprendizaje, dificultades de acceso para los alumnos con discapacidad visual. Los autores, integrantes del Grupo de Accesibilidad a Contenidos Digitales de la ONCE (ACCEDO), analizan el papel de los profesores y las familias, presentando las principales tecnologías y herramientas de apoyo para alumnos ciegos o con baja visión utilizadas en Educación Infantil y primeros cursos de Primaria, tales como: revisores de pantalla, línea braille, impresoras braille, tableta digitalizadora, pantalla táctil y pantalla digital interactiva

E-inclusión en la escuela ordinaria para alumnos con discapacidad visual. Internet como herramienta de apoyo

En este artículo se presenta la investigación que se está llevando a cabo por parte del Grupo ACCEDO con 21 alumnos del segundo ciclo de Educación Primaria y sus maestros itinerantes, enmarcada dentro del Plan Avanza 2009, con el objetivo de determinar las habilidades y estrategias que requieren los alumnos para el manejo de la tecnología en al aula, con Internet como herramienta de apoyo, así como los criterios metodológicos necesarios para optimizar su uso. Se presentan también los estudios previos realizados a tal fin, así como las actuaciones llevadas a cabo hasta el momento

Emotional interference-based forgetting in short-term memory. Cognitive inhibition of pleasant but not unpleasant biologically relevant distractors

Emotional stimuli automatically recruit attentional resources. Although this usually brings more adaptive responses, it may suppose a disadvantage when emotional information is task-irrelevant and should be ignored. Previous studies have shown how emotional stimuli with a negative content exert a greater interference than neutral stimuli during a concurrent working memory (WM) task. However, the impact of positively valenced stimuli as interference has not been addressed to date. In three experiments and one re-analysis we explore the impact of pleasant and unpleasant emotional distractors during WM maintenance. The results suggest that our cognitive control can cope with the interference posed by pleasant distractors as well as with the interference posed by neutral stimuli. However, unpleasant distractors are harder to control in the context of WM maintenance. As unpleasant stimuli usually convey relevant information that we should not to ignore, our executive control seems to be less able to reallocate cognitive resources after unpleasant distraction