Use of Novel Spatial Presentations of Plant Species to Improve Legume Abundance

The benefits of using white clover (Trifolium repens) in pasture grazed by sheep have been widely recognised. However, clover is considered inadequate and risky as the main source of nitrogen input, since its abundance in the pasture is patchy, low (typically less than 20%) and shows great year-to-year variation. This is thought to be due to the costs of nitrogen fixation, competition with grass, the preference for clover by sheep and patchy dung and urine deposition (Schwinning & Parsons, 1996). One possible solution may be the spatial separation of clover from grass, which would remove inter-specific competition, allowing clover to grow unimpeded in a greater abundance than previously observed. Spatial separation can occur over a range of spatial scales, from narrow strips of alternating clover and grass to complete separation, where half a pasture is clover while the other half is grass. This in turn may have a significant impact on the processes occurring within the pasture, such as plant growth and spread, nitrogen cycling and animal behaviour

Pitfalls of Teachers on Modular Distance Learning: Basis for a Proposed Action Plan

The study was conducted to determine the pitfalls encountered by grade five teachers during modular teaching and learning. Specifically, it aimed to find out the pitfalls encountered by teachers along with students’ comprehension, students’ academic behavior, monitoring of students’ education, and physical interaction with the learners. The personal profile of teachers, out of the total respondents (56), most of the teachers are female-dominated. Most of them belong to the age bracket of 34 to 45 and most of the teachers are married. Most of the teachers had attended post-graduate studies. Most respondents are still young in the service, holding Teacher 2 and Teacher 3 positions, and attending local, national, and regional training. On the level of pitfalls encountered by teachers in modular teaching and learning, most respondents experienced a slight gravity level in the four aspects. The computed average weighted mean along comprehension is 2.50, along academic behavior is 2.54, along monitoring of students’ performance is 2.58, and along physical interaction is 2.79. All have an equivalent value of moderately grave. There is a specific profile of teachers that is significantly related. Age is significantly associated with monitoring students’ learning. The computed r value is .270, while the calculated significance level is 0.04. Training attended by the teachers is significantly related to some aspects of students’ comprehension, (computed sig. value is 0.04 and physical interaction is .02), which is lower than the .05 level of significance. The grade five teachers who served as respondents are mostly female dominated; they are in their early forties and married. Most of them are attending post-graduate studies and have attended relevant training. Second, the level of teachers’ pitfalls is mostly moderately grave. In addition, age is significantly related to monitoring, training is significantly associated substantially with physical interaction and comprehension

Optimización estructural y operativa de sistemas de evaporación

En este trabajo se estudia la optimización simultánea de la estructura y la planificación operativa y de mantenimiento (por limpieza) de sistemas de evaporación con múltiples unidades, teniéndose en cuenta el efecto del ensuciamiento de los equipos, utilizando programación matemática. Como estrategia de optimización se utilizó el concepto de ciclo de operación y limpieza, que debe ser repetido tantas veces como sea necesario para alcanzar la producción de planta requerida. El modelo matemático de optimización desarrollado utiliza variables continuas y binarias por lo que resulta de tipo no lineal mezcla entera (MINLP). Se presentan resultados de la comparación de un caso práctico correspondiente a un ingenio azucarero, con la solución óptima resultante del modelo, mostrando una reducción del orden del 2 % en términos de costo anual equivalente y del 5,5 % los costos horarios.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Understanding disease control: influence of epidemiological and economic factors

We present a local spread model of disease transmission on a regular network and compare different control options ranging from treating the whole population to local control in a well-defined neighborhood of an infectious individual. Comparison is based on a total cost of epidemic, including cost of palliative treatment of ill individuals and preventive cost aimed at vaccination or culling of susceptible individuals. Disease is characterized by pre- symptomatic phase which makes detection and control difficult. Three general strategies emerge, global preventive treatment, local treatment within a neighborhood of certain size and only palliative treatment with no prevention. The choice between the strategies depends on relative costs of palliative and preventive treatment. The details of the local strategy and in particular the size of the optimal treatment neighborhood weakly depends on disease infectivity but strongly depends on other epidemiological factors. The required extend of prevention is proportional to the size of the infection neighborhood, but this relationship depends on time till detection and time till treatment in a non-nonlinear (power) law. In addition, we show that the optimal size of control neighborhood is highly sensitive to the relative cost, particularly for inefficient detection and control application. These results have important consequences for design of prevention strategies aiming at emerging diseases for which parameters are not known in advance

Improving animal welfare using continuous nalbuphine infusion in a long-term rat model of sepsis

Abstract Background Sepsis research relies on animal models to investigate the mechanisms of the dysregulated host response to infection. Animal welfare concerns request the use of potent analgesics for the Refinement of existing sepsis models, according to the 3Rs principle. Nevertheless, adequate analgesia is often missing, partly because the effects of analgesics in this particular condition are unknown. We evaluated the use of nalbuphine, an opioid with kappa agonistic and mu antagonistic effects, in rats with and without experimental sepsis. Methods Male Wistar rats were anesthetized with isoflurane and instrumented with a venous line for drug administration. Arterial cannulation allowed for blood pressure measurements and blood sampling in short-term experiments of non-septic animals. Nalbuphine (or placebo) was administered intravenously at a dose of 1 mg/kg/h. Long-term (48 h) experiments in awake septic animals included repetitive clinical scoring with the Rat Grimace Scale and continuous heart rate monitoring by telemetry. Sepsis was induced by intraperitoneal injection of faecal slurry. Nalbuphine plasma levels were measured by liquid chromatography—high resolution mass spectrometry. Results In anesthetized healthy animals, nalbuphine led to a significant reduction of respiratory rate, heart rate, and mean arterial pressure during short-term experiments. In awake septic animals, a continuous nalbuphine infusion did not affect heart rate but significantly improved the values of the Rat Grimace Scale. Nalbuphine plasma concentrations remained stable between 4 and 24 h of continuous infusion in septic rats. Conclusions In anaesthetised rats, nalbuphine depresses respiratory rate, heart rate, and blood pressure. In awake animals, nalbuphine analgesia improves animal welfare during sepsis

Repositionable Versus Balloon-Expandable Devices for Transcatheter Aortic Valve Implantation in Patients With Aortic Stenosis.

The safety and effectiveness of the fully repositionable LOTUS valve system as compared with the balloon-expandable Edwards SAPIEN 3 prosthesis for the treatment of aortic stenosis has not been evaluated to date. All patients undergoing transcatheter aortic valve implantation with the Edwards SAPIEN 3 or the LOTUS valve system were included into the Swiss Transcatheter Aortic Valve Implantation Registry. An adjusted analysis was performed to compare the early clinical safety outcome according to the Valve Academic Research Consortium-2 definition. Between February 2014 and September 2015, 140 and 815 patients were treated with the LOTUS and the Edwards SAPIEN 3 valve, respectively. There was no difference in crude and adjusted analyses of the early safety outcome between patients treated with LOTUS (14.3%) and those treated with Edwards SAPIEN 3 (14.6%) (crude hazard ratio, 0.97; 95% CI, 0.61-1.56 [P=0.915]; adjusted hazard ratio, 1.03; 95% CI, 0.64-1.67 [P=0.909]). More than mild aortic regurgitation was <2% for both devices. A total of 34.3% of patients treated with LOTUS and 14.1% of patients treated with Edwards SAPIEN 3 required a permanent pacemaker (HR, 2.76; 95% CI, 1.97-3.87 [P<0.001]). The repositionable LOTUS valve system and the balloon-expandable Edwards SAPIEN 3 prosthesis appeared comparable in regard to the Valve Academic Research Consortium-2 early safety outcome, and the rates of more than mild aortic regurgitation were exceedingly low for both devices. The need for new permanent pacemaker implantation was more frequent among patients treated with the LOTUS valve

Impacts of climate change on plant diseases – opinions and trends

There has been a remarkable scientific output on the topic of how climate change is likely to affect plant diseases in the coming decades. This review addresses the need for review of this burgeoning literature by summarizing opinions of previous reviews and trends in recent studies on the impacts of climate change on plant health. Sudden Oak Death is used as an introductory case study: Californian forests could become even more susceptible to this emerging plant disease, if spring precipitations will be accompanied by warmer temperatures, although climate shifts may also affect the current synchronicity between host cambium activity and pathogen colonization rate. A summary of observed and predicted climate changes, as well as of direct effects of climate change on pathosystems, is provided. Prediction and management of climate change effects on plant health are complicated by indirect effects and the interactions with global change drivers. Uncertainty in models of plant disease development under climate change calls for a diversity of management strategies, from more participatory approaches to interdisciplinary science. Involvement of stakeholders and scientists from outside plant pathology shows the importance of trade-offs, for example in the land-sharing vs. sparing debate. Further research is needed on climate change and plant health in mountain, boreal, Mediterranean and tropical regions, with multiple climate change factors and scenarios (including our responses to it, e.g. the assisted migration of plants), in relation to endophytes, viruses and mycorrhiza, using long-term and large-scale datasets and considering various plant disease control methods

Downy Mildew of Sorghum. Information Bulletin no. 51

Downy mildew of sorghum (Peronosclerospora sorghi) is one of the most important diseases of sorghum and maize. It is distributed widely in Africa, Asia, and the Americas, where serious epidemics occur. Systemic infection causes complete or partial sterility of the panicle, resulting in yield loss roughly proportional to the disease incidence. The seriousness of the problem has resulted in significant investment to increase knowledge of the pathogen and to investigate various disease control measures. Several alternatives for the control of sorghum downy mildew are now available including cultural and chemical control, and the deployment of resistant varieties. The current state of knowledge of the pathogen's biology, epidemiology, variability, and control are described in this bulletin, together with practical aspects of disease management

Balancing Detection and Eradication for Control of Epidemics: Sudden Oak Death in Mixed-Species Stands

Culling of infected individuals is a widely used measure for the control of several plant and animal pathogens but culling first requires detection of often cryptically-infected hosts. In this paper, we address the problem of how to allocate resources between detection and culling when the budget for disease management is limited. The results are generic but we motivate the problem for the control of a botanical epidemic in a natural ecosystem: sudden oak death in mixed evergreen forests in coastal California, in which species composition is generally dominated by a spreader species (bay laurel) and a second host species (coast live oak) that is an epidemiological dead-end in that it does not transmit infection but which is frequently a target for preservation. Using a combination of an epidemiological model for two host species with a common pathogen together with optimal control theory we address the problem of how to balance the allocation of resources for detection and epidemic control in order to preserve both host species in the ecosystem. Contrary to simple expectations our results show that an intermediate level of detection is optimal. Low levels of detection, characteristic of low effort expended on searching and detection of diseased trees, and high detection levels, exemplified by the deployment of large amounts of resources to identify diseased trees, fail to bring the epidemic under control. Importantly, we show that a slight change in the balance between the resources allocated to detection and those allocated to control may lead to drastic inefficiencies in control strategies. The results hold when quarantine is introduced to reduce the ingress of infected material into the region of interest