Rendimiento de la canal y ganancia de peso en vacas de descarte con inducción del anestro por vías quirúrgica versus mecánica

Orquera, M.L.; Pochon, D.O.; Flores, S.; Konrad, J.L.; Crudeli, G.A.: Rendimiento de la canal y ganancia de peso en vacas de descarte con inducción de anestro por vías quirúrgica versus mecánica. Rev. vet. 22: 1, 64–67, 2011. Palabras clave: vaca descarte, dispositivo intrauterino, castración quirúrgica, ganancia de peso, performance de canal

Social cooperation and resource management dynamics among late hunter-fisher-gatherer societies in Tierra del Fuego (South America)

This paper presents the theoretical basis and first results of an agent-based model (ABM) computer simulation that is being developed to explore cooperation in hunter–gatherer societies. Specifically, we focus here on Yamana, a hunter-fisher-gatherer society that inhabited the islands of the southernmost part of Tierra del Fuego (Argentina–Chile). Ethnographical and archaeological evidence suggests the existence of sporadic aggregation events, triggered by a public call through smoke signals of an extraordinary confluence of resources under unforeseeable circumstances in time and space (a beached whale or an exceptional accumulation of fish after a low tide, for example). During these aggregation events, the different social units involved used to develop and improve production, distribution and consumption processes in a collective way. This paper attempts to analyse the social dynamics that explain cooperative behaviour and resource-sharing during aggregation events using an agent-based model of indirect reciprocity. In brief, agents make their decisions based on the success of the public strategies of other agents. Fitness depends on the resource captured and the social capital exchanged in aggregation events, modified by the agent’s reputation. Our computational results identify the relative importance of resources with respect to social benefits and the ease in detecting—and hence punishing—a defector as key factors to promote and sustain cooperative behaviour among populationSpanish Ministerio de Ciencia e Innovación (projects CONSOLIDER-INGENIO 2010 SimulPast-CSD2010-00034 and HAR2009-06996) as well as from the Argentine Consejo Nacional de Investigaciones Científicas y Técnicas (project PIP-0706) and the Wenner-Gren Foundation for Anthropological Research (project GR7846)

Longer and less overlapping food webs in anthropogenically disturbed marine ecosystems: confirmations from the past

The human exploitation of marine resources is characterised by the preferential removal of the largest species. Although this is expected to modify the structure of food webs, we have a relatively poor understanding of the potential consequences of such alteration. Here, we take advantage of a collection of ancient consumer tissues, using stable isotope analysis and SIBER to assess changes in the structure of coastal marine food webs in the South-western Atlantic through the second half of the Holocene as a result of the sequential exploitation of marine resources by hunter-gatherers, western sealers and modern fishermen. Samples were collected from shell middens and museums. Shells of both modern and archaeological intertidal herbivorous molluscs were used to reconstruct changes in the stable isotopic baseline, while modern and archaeological bones of the South American sea lion Otaria flavescens, South American fur seal Arctocephalus australis and Magellanic penguin Spheniscus magellanicus were used to analyse changes in the structure of the community of top predators. We found that ancient food webs were shorter, more redundant and more overlapping than current ones, both in northern-central Patagonia and southern Patagonia. These surprising results may be best explained by the huge impact of western sealing on pinnipeds during the fur trade period, rather than the impact of fishing on fish populations. As a consequence, the populations of pinnipeds at the end of the sealing period were likely well below the ecosystem's carrying capacity, which resulted in a release of intraspecific competition and a shift towards larger and higher trophic level prey. This in turn led to longer and less overlapping food webs

Effect of resource spatial correlation and Hunter-Fisher-Gatherer mobility on social cooperation in Tierra del Fuego

This article presents an agent-based model designed to explore the development of cooperation in hunter-fisher-gatherer societies that face a dilemma of sharing an unpredictable resource that is randomly distributed in space. The model is a stylised abstraction of the Yamana society, which inhabited the channels and islands of the southernmost part of Tierra del Fuego (Argentina-Chile). According to ethnographic sources, the Yamana developed cooperative behaviour supported by an indirect reciprocity mechanism: whenever someone found an extraordinary confluence of resources, such as a beached whale, they would use smoke signals to announce their find, bringing people together to share food and exchange different types of social capital. The model provides insight on how the spatial concentration of beachings and agents’ movements in the space can influence cooperation. We conclude that the emergence of informal and dynamic communities that operate as a vigilance network preserves cooperation and makes defection very costly.MICINN http://www.idi.mineco.gob.es/ CSD2010-00034 (SimulPast CONSOLIDER-INGENIO 2010) and HAR2009-06996; the government of Castilla y Leónhttp://www.jcyl.es/ GREX251-2009; the Argentine CONICET http://www.conicet.gov.ar/PIP-0706; and the Wenner-Gren Foundation for Anthropological Researchhttp://www.wennergren.org/ "Social Aggregation: A Yamana Society's Short Term Episode to Analyse Social Interaction, Tierra del Fuego, Argentina". The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

Hunter–gatherer mobility and technological landscapes in southernmost South America: a statistical learning approach

The present work aims to quantitatively explore and understand the relationship between mobility types (nautical versus pedestrian), specific technological traits and shared technological knowledge in pedestrian hunter–gatherer and nautical hunter–fisher–gatherer societies from the southernmost portion of South America. To that end, advanced statistical learning techniques are used: state-of-the-art classification algorithms and variable importance analyses. Results show a strong relationship between technological knowledge, traits and mobility types. Occupations can be accurately classified into nautical and pedestrian due to the existence of a non-trivial pattern between mobility and a relatively small fraction of variables from some specific technological categories. Cases where the best-fitted classification algorithm fails to generalize are found significantly interesting. These instances can unveil lack of information, not enough entries in the training set, singular features or ambiguity, the latter case being a possible indicator of the interaction between nautical and pedestrian societies.HAR-2009-06996, CSD2010-00034, HAR2017- 90883-REDC, CULM-HAR2016-77672-P (Ministerio de Ciencia e Innovacio´n de Espan˜ a); PIP-0706, PIP-0348 (Consejo Nacional de Investigaciones Cientı´ficas y Tecnolo´gicas-Argentina) and PICT 2012-2148 (Ministerio de Ciencia, Tecnologı´a e Innovacio´n Productiva de la Repu´ blica Argentina); PROC/12-120610-A (SESAR WPE Long Term and Innovative Research-European Commission); and Project GR-7846 (Wenner-Gren Foundation for Anthropological Research

Utilization of mechanical power and associations with clinical outcomes in brain injured patients. a secondary analysis of the extubation strategies in neuro-intensive care unit patients and associations with outcome (ENIO) trial

BackgroundThere is insufficient evidence to guide ventilatory targets in acute brain injury (ABI). Recent studies have shown associations between mechanical power (MP) and mortality in critical care populations. We aimed to describe MP in ventilated patients with ABI, and evaluate associations between MP and clinical outcomes.MethodsIn this preplanned, secondary analysis of a prospective, multi-center, observational cohort study (ENIO, NCT03400904), we included adult patients with ABI (Glasgow Coma Scale <= 12 before intubation) who required mechanical ventilation (MV) >= 24 h. Using multivariable log binomial regressions, we separately assessed associations between MP on hospital day (HD)1, HD3, HD7 and clinical outcomes: hospital mortality, need for reintubation, tracheostomy placement, and development of acute respiratory distress syndrome (ARDS).ResultsWe included 1217 patients (mean age 51.2 years [SD 18.1], 66% male, mean body mass index [BMI] 26.3 [SD 5.18]) hospitalized at 62 intensive care units in 18 countries. Hospital mortality was 11% (n = 139), 44% (n = 536) were extubated by HD7 of which 20% (107/536) required reintubation, 28% (n = 340) underwent tracheostomy placement, and 9% (n = 114) developed ARDS. The median MP on HD1, HD3, and HD7 was 11.9 J/min [IQR 9.2-15.1], 13 J/min [IQR 10-17], and 14 J/min [IQR 11-20], respectively. MP was overall higher in patients with ARDS, especially those with higher ARDS severity. After controlling for same-day pressure of arterial oxygen/fraction of inspired oxygen (P/F ratio), BMI, and neurological severity, MP at HD1, HD3, and HD7 was independently associated with hospital mortality, reintubation and tracheostomy placement. The adjusted relative risk (aRR) was greater at higher MP, and strongest for: mortality on HD1 (compared to the HD1 median MP 11.9 J/min, aRR at 17 J/min was 1.22, 95% CI 1.14-1.30) and HD3 (1.38, 95% CI 1.23-1.53), reintubation on HD1 (1.64; 95% CI 1.57-1.72), and tracheostomy on HD7 (1.53; 95%CI 1.18-1.99). MP was associated with the development of moderate-severe ARDS on HD1 (2.07; 95% CI 1.56-2.78) and HD3 (1.76; 95% CI 1.41-2.22).ConclusionsExposure to high MP during the first week of MV is associated with poor clinical outcomes in ABI, independent of P/F ratio and neurological severity. Potential benefits of optimizing ventilator settings to limit MP warrant further investigation

Carcass performance and weight gain in cull cows with anestrus induced by surgical versus mechanic ways

El presente trabajo tuvo por objetivo evaluar la ganancia de peso y rendimiento de la canal en vacas descarte mestizas (n=47), con dispositivo intrauterino bovino (DIUB) y castradas quirúrgicamente. Con el propósito de adjudicar los tratamientos, las unidades experimentales fueron separadas al azar en tres gru-pos: G1) 15 vacas controles, G2) 19 vacas castradas y G3) 15 vacas con DIUB. Los animales fueron alojados en un potrero con pastura natural, con amplio predominio de Gatton panic. Se realizaron pesajes al inicio y cada treinta días, durante 120 días, para evaluar ganancia total de peso para los tres grupos. Al fnal los animales fueron faenados tras un ayuno previo de doce horas, a fn de determinar el rendimiento de la canal. Empleando un diseño com-pletamente aleatorizado, el análisis de la variancia arrojó diferencias de peso signifcativas entre G1 y G3 (120 días): 77,6 vs 108 kg respectivamente (p<0,05) y entre G2 y G3 (120 días): 81,4 vs 108 kg respectivamente (p<0,05). También fueron signifcativas las diferencias del rendimiento de la canal entre G1 y G2 (51,02 vs 52,94% respectivamente, p<0,05), mientras que G2 y el G3 fueron similares para este parámetro. No se registraron diferencias signif-cativas entre las ganancias de peso de G1 y G2 (120 días): 77,6 vs 81,4 kg. Los resultados demostraron que G3 fue más efciente que G1 y G2 en ganancia de peso, en tanto que para el rendimiento de la canal G2 y G3 revelaron mejor desempeño. Se concluye que la aplicación de DIUB se traduce en una mejor relación costo–benefcio.The purpose of this research is to assess the weight incre-ment of crossbred cull cows with intra–uterine device (IUD) versus cows surgically neu-tered. To determine the effcacy of treatments, cows were grouped as follows: G1: 15 cows (control), G2: 19 cows neutered, and G3: 15 cows IUD. Animals were fed on natural pasture, being Gatton panic the most abundant. Weight controls were registered at the beginning of the assay, and then every thirty days during a period of 120 days. Finally, to register the carcass performance of the groups, cows were slaughtered with a previous fast of 12 hours. Signifcant liveweight differences were observed between G1 and G3 (120 days): 77.6 vs. 108 kg (p<0.05), and between G2 and G3 (120 days): 81.4 vs. 108 kg (p<0.05). Statistical differ-ences in carcass performance were observed between G1 and G2: 51.02 vs. 52.94% (p<0.05). No signifcant differences were observed between G1 and G2 (120 days): 77.6 vs. 81.4 kg. Results indicate that animals from group G3 gained more weight in comparison to G1 and G2. Regarding carcass performance, groups G2 and G3 revealed a better effciency. It can be concluded that the use of IUD leads to a better cost–beneft relationship.Fil: Orquera, M. L.. Universidad Nacional del Nordeste; ArgentinaFil: Pochon, Daniel Osvaldo. Universidad Nacional del Nordeste; ArgentinaFil: Flores, S.. Universidad Nacional del Nordeste; ArgentinaFil: Konrad, José Luis. Universidad Nacional del Nordeste; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Crudeli, Gustavo Angel. Universidad Nacional del Nordeste; Argentin