Effects of Concentrate Supplementation During Summer on Animal Performance and Heat Stress of Angus Steers Grazing Native Grasslands in Uruguay

Research in temperate grasslands has addressed livestock supplementation (SUPL) mainly during winter, but more studies are needed on the impact of SUPL during summer where heat stress (HS) conditions may occur. The objective of this study was to evaluate the effects of summer SUPL on average daily gain (ADG), respiratory rate (RR), and body temperature (BT) of steers grazing native grasslands (60% TDN, 7.3% CP) in Uruguay (33°14\u27S, 54°15\u27W). Eighteen 15-month-old Angus steers (285±11 kg) were randomly assigned to 6 groups (2 treatments x 3 replicates) with free access to shade and water on a continuous stocking system (1.5 steer/ha) for 84 days. Treatments were SUPL and un-supplemented (un-SUPL) cattle. Supplement (77% TDN, 16.8% CP) was delivered 3 days/week at 2.3% BW. Animal breaths per minute (bpm) were registered in 18 days at 09:00 am, 12:00 pm, and 03:00 pm by visual observation and BT was hourly recorded using a subcutaneously implanted logger. The temperature-humidity index (THI) was calculated hourly using air temperature and relative humidity recorded by automatic sensors. According to THI, cattle was in the \u27normal\u27 category (THI \u3c 74, absence of weather-based HS) during 72% of the time, the rest being exposed to ‘moderate’ (19%) and ‘severe’ (9%) HS. Supplemented steers had greater (P \u3c 0.05) ADG than CONT cattle (mean ± s.e.m.: 0.729±0.053 and 0.393±0.169, respectively). Respiration rate was no affected by SUPL (P \u3e 0.05), averaging 45±1 (09:00 am), 56±2 (12:00 pm), and 62±3 (03:00 pm) bpm across treatments. Supplementation did not increase daily BT (P \u3e 0.05), averaging (±s.e.m.) 38.2±0.1°C across treatments. The greatest BT difference (P \u3e 0.05) between groups was observed at 09:00-10:00 am, coincidently with the time of supplementation (SUPL: 39.3±0.1°C; un-SUPL: 38.3±0.1°C). Summer supplementation in native grasslands resulted in better animal performance without affecting animal-based heat stress indices compared to un-supplemented steers

A singular structure: Monopost made in composites

p. 3002-3012This work presents the design process, the analysis, and the performance of a cylindrical hollow monopost, made entirely in composites. It is about a translucent structure of height 40m, external diameter 1.60m and the average wall-thickness 11mm. The material is a polymer made up of vinylster resin and reinforced by glass fiber (GFRP). The manufactured processing used is filament winding. Moreover, due to geographical emplacement where it is situated, the structure has to support wind velocity value above 180Km/h and its elastic modulus of the material does not exceed 25GPa. Eventually, we was able to achieve an optimum solution and strentgh structure, considering and developing differents types of approaches and analysis, such as linear, non-linear and buckling.Rovira, JA.; Martin, P.; Pons, D.; Almerich Chulia, AI. (2009). A singular structure: Monopost made in composites. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/670

Características de los ejercicios de prácticas de laboratorio incluidos en los libros de textos de Ciencias utilizados en Cataluña

The laboratory exercices in science textbooks used in grades 9 to 12 in Catalonian schools were content analyzed by three instruments: The Inquiry Leve1 Index (ILI), the Laboratory Assessment Inventory (LAI) and the Laboratory Dimenssions Inventory (LDI). The analysis was carried out by 24 teachers under the guidance of two science educators as an assignment in an in-service course on teaching and evaluation in the laboratory. It was found that the number of laboratory exercises offered in Catalonian science texbooks is rather small compared with texbooks in countries such as the U. K. and U.S.A. Most of the exercises are of low inquiry level featuring manipulation but missing high other inquiry skills such as formulating questions and hypotheses, designing experiments, etc. The relationship between practical work and theory is hardly indicated and the potential of the laboratory as a means to enhancing concept learning andlor developing social skills are hardly being considered. There is an urgent need to reform laboratory work in Catalonian schools

The Importance of Campos Ecosystem as a World Food Producer and as a Provider of Ecosystem Services

The Campos ecosystem represent one of the largest grassland areas on the world, with great biodiversity in plants and animals. It contributes to improve world food security, based on ruminant livestock production, providing animal protein to feed more than 160.000.000 people. The research agenda for Campos ecosystem demands attention on the productivity and increasing variability phenomena, overgrazing, biodiversity standards and water contamination among other factors. It provides services including genetic resources, carbon storage, control of soil erosion, nutrient recycling, water production with low nutrient concentration and pest control. Overall, there is available technology to improve long-term livestock productivity and preserve current environmental indicators and improve sustainability, contributing to supply increasing world food demand

Desempeño productivo de novillos sobre pasturas templadas con suplementación energética en autoconsumo

La suplementación de bovinos en autoconsumo puede ser una alternativa válida para disminuir los costos de tiempo y mano de obra asociados al suministro diario de ración. El objetivo fue evaluar la suplementación energética en autoconsumo en el engorde de novillos (326±23 kg) sobre pasturas templadas de alta calidad. Los tratamientos fueron: 1) testigo sin suplementación, 2) suplementación diaria 1% del peso vivo (PV), 3) suplementación restringida en autoconsumo 1% PV con recarga semanal del comedero, 4) suplementación ad libitum en autoconsumo. En los tratamientos con autoconsumo se utilizó ración con 10% de sal para limitar consumo. El consumo de ración en autoconsumo ad-libitum fue 6,7 kg/a/d (1,8% PV), significativamente más alto que el registrado en los tratamientos al 1% PV, ya sea bajo suministro diario (3,6 kg/a/d) o autoconsumo restringido (3,7 kg/a/d). En éste último tratamiento, el comedero quedó desprovisto de ración 2 a 3 días por semana para ajustar el nivel de suplementación a 1% PV. El peso vivo final y la ganancia de peso fue significativamente mayor (p < 0,05) en los animales suplementados (382±29 kg y 1,012±0,546 kg/a/d, respectivamente) comparado con el grupo testigo (329±25 kg y 0,198±0,276 kg/a/d), no existiendo diferencias asociadas al método de entrega de la ración (p > 0,05). La eficiencia de conversión (kg de ración para ganar 1 kg de PV adicional comparado con el grupo testigo) tendió a desmejorar en los tratamientos de autoconsumo (5,2 y 6,9 kg restringido y ad-libitum, respectivamente) comparado con la suplementación diaria (4,7 kg). Los animales suplementados registraron mayor área de ojo de bife y grasa intramuscular y subcutánea que los animales sin suplementación. La suplementación en autoconsumo es una estrategia válida para facilitar operativamente esquemas de suplementación, aunque biológicamente la eficiencia de conversión puede verse afectada por el consumo de ración con alto contenido de sal

Evaluation of laser range-finder mapping for agricultural spraying vehicles

In this paper, we present a new application of laser range-finder sensing to agricultural spraying vehicles. The current generation of spraying vehicles use automatic controllers to maintain the height of the sprayer booms above the crop. However, these control systems are typically based on ultrasonic sensors mounted on the booms, which limits the accuracy of the measurements and the response of the controller to changes in the terrain, resulting in a sub-optimal spraying process. To overcome these limitations, we propose to use a laser scanner, attached to the front of the sprayer's cabin, to scan the ground surface in front of the vehicle and to build a scrolling 3d map of the terrain. We evaluate the proposed solution in a series of field tests, demonstrating that the approach provides a more detailed and accurate representation of the environment than the current sonar-based solution, and which can lead to the development of more efficient boom control systems

Exchange coupling inversion in a high-spin organic triradical molecule

The magnetic properties of a nanoscale system are inextricably linked to its local environment. In ad-atoms on surfaces and inorganic layered structures the exchange interactions result from the relative lattice positions, layer thicknesses and other environmental parameters. Here, we report on a sample-dependent sign inversion of the magnetic exchange coupling between the three unpaired spins of an organic triradical molecule embedded in a three-terminal device. This ferro-to-antiferromagnetic transition is due to structural distortions and results in a high-to-low spin ground state change in a molecule traditionally considered to be a robust high-spin quartet. Moreover, the flexibility of the molecule yields an in-situ electric tunability of the exchange coupling via the gate electrode. These findings open a route to the controlled reversal of the magnetic states in organic molecule-based nanodevices by mechanical means, electrical gating or chemical tailoring

Management and Productivity of Key Integrated Crop-Livestock Systems in Uruguay: The Palo a Pique Long-Term Experiment’s Third Phase

Integrated Crop Livestock Systems (ICLSs) use productive diversification as a strategy to improve productivity and land use efficiency. Pasture Crop Rotations are a part of ICLSs and imply a pasture phase included in the sequence of crops. The main reasons to include pastures in crop systems are low productivity of natural grasslands and increased crop yield after a pasture phase. Our objective was to analyze the productivity indicators and management of four ICLSs that combine crop and livestock production, with data collected over a 3 y period (2019–2022). The experimental site was The Palo a Pique (Treinta y Tres, Uruguay) long-term experiment installed in 1995, located in the subtropical climate zone and on Oxyaquic Argiudolls soils (3% average slope). Systems evaluated were CC (continuous cropping), SR (two years idem CC, two years of pastures), LR (two years idem CC, four years of pastures) and FR (continuous pasture with Tall Fescue). Liveweight (LW) production, grain production and dry matter (DM) production were evaluated. Liveweight production was higher in CC and SR (426 and 418 kg LW/ha) than in LR (369 kg LW/ha) and FR (310 kg LW/ha). DM production was higher in FR and SR (6867 and 5763 kg DM/ha/year) than in LR (5399 kg DM/ha/year) and CC (5206 kg DM/ha/year). Grain production was 10%, 16% and 9% lower in soybean, wheat and sorghum in CC

Guidance and surroundings awareness in outdoor handheld augmented reality

Handheld and wearable devices are becoming ubiquitous in our lives and augmented reality technology is stepping out of the laboratory environment and becoming ready to be used by anyone with portable devices. The success of augmented reality applications for pedestrians depends on different factors including a reliable guidance system and preventing risks. We show that different guidance systems can be supplementary to provide directions to a point of interest and offer clues that help the user find the augmented data when they get close to the location they have to visit. We tested the helpfulness of a map with the points of interest, an image preview of the next point of interest to visit, and an arrow showing the direction to it. The results show that the effectiveness of these guidance systems depend on the distance to the point of interest and the accuracy of the data obtained from the Global Positioning System. We also measured the total time that participants spent looking at the screen, as well as the perceived elapsed time as a measurement of real world dissociation. Finally, we discuss preliminary results to minimize the risk of accidents when using augmented reality applications in an outdoor urban environment