375 research outputs found
Patterning molecular scale paramagnets at Au Surface: A root to Magneto-Molecular-Electronics
Few examples of the exploitation of molecular magnetic properties in
molecular electronics are known to date. Here we propose the realization of
Self assembled monolayers (SAM) of a particular stable organic radical. This
radical is meant to be used as a standard molecule on which to prove the
validity of a single spin reading procedure known as ESR-STM. We also discuss a
range of possible applications, further than ESR-STM, of magnetic monolayers of
simple purely organic magnetic molecule.Comment: This preprint is currently partially under revisio
How to Create Conditioned Taste Aversion for Grazing Ground Covers in Woody Crops with Small Ruminants
Conditioned taste aversion (CTA) is a learning behavior process where animals are trained to reject certain feed after gastrointestinal discomfort has been produced. Lithium chloride (LiCl) is the preferred agent used in livestock to induce CTA because it specifically stimulates the vomit center. In addition, LiCl is commercially available, and easy to prepare and administer using a drenching gun. Nevertheless, some factors have to be considered to obtain an effective long-lasting CTA, which allows small ruminants to graze during the cropping season. A key aspect is to use animals with no previous contact with the target plant (the plant chosen to be avoided; new feed). Due to their native neophobic feeding behavior, small ruminants can easily associate the negative feedback effects with the new feed, resulting in a strong and persistent CTA. The recommended doses are 200 and 225 mg LiCl/kg body weight (BW) for goats and sheep, respectively. To induce CTA, 100 g of the target plant should be individually offered for at least 30 min, and LiCl administered thereafter if the intake is greater than 10 g. Each time the animal eats the target plant without negative consequences, the CTA becomes weaker. Consequently, to minimize the risk of target plant consumption, it is essential to have sufficient palatable ground cover available. The presence of an alternative feed (of quality and quantity) prevents the accidental consumption of the target plant. A close monitoring of the flock is recommended to remove and re-dose any animal consuming more than 4 bites or 10 g of the target plant. At the beginning of each grazing season, check the CTA status of each animal before moving them to the crop
Pasturatge en oliverars: aplicació de l'aversió condicionada a l'olivera en cabres
Cada dia l'agricultura incorpora noves pràctiques més respectuoses amb el medi ambient intentant aprofitar millor els recursos naturals i preservar-los de cara al futur. En el cas de l'oliverar, l'erosió que pateix el sòl, a causa de les pràctiques tradicionals de conreu, ha propiciat la implantació de cobertes vegetals que es controlen mitjançant l'ús de maquinària, o bé amb herbicides. L'inconvenient que comporten aquestes pràctiques i la inquietud per pràctiques més sostenibles han afavorit l'estudi de l'ús de bestiar per pasturar els camps d'oliveres. L'inconvenient és que les fulles de les oliveres són un aliment molt atractiu per a cabres i ovelles i poden malmetre l'arbre. Amb la finalitat que les cabres rebutgin menjar fulles d'olivera, es planteja la possibilitat de modificar el seu comportament alimentari, utilitzant diferents dosis de clorur de liti (LiCl), 175 mg LiCl/kg PV i 200 mg LiCl/kg PV. Els resultats obtinguts en cabres murcianogranadines mostren la possibilitat de generar aversió a les fulles d'olivera, que es va mantenir durant catorze mesos. L'aversió va ser més efectiva en el cas de les cabres que van rebre la dosi de 200 mg LiCl/kg PV.Each day brings new and more environmentally friendly practices to farming, trying to make better use of natural resources and to preserve them for the future. In the case of olive groves, the soil erosion to which this crop is exposed because of traditional farming systems is offset by the introduction of groundcover which is controlled by the use of machinery or herbicides. The drawback involved by these practices and concerns about more sustainable systems has encouraged the study of the use of grazing animals in olive groves. However, olive leaves are very attractive to goats and sheep, which could damage the trees. In order to make goats reject olive leaves, the aim of this study was to modify their feeding behaviour using lithium chloride (LiCl) in various doses (175 mg LiCl/kg BW and 200 mg LiCl/kg BW). The results obtained with Murciano-Granadina goats show that it is possible to generate a conditioned taste aversion to olive leaves, which was maintained for 14 months. Aversion was more effective in goats which received the 200 mg LiCl/kg BW dose.Cada día la agricultura incorpora nuevas prácticas más respetuosas con el medio ambiente intentando aprovechar mejor los recursos naturales y preservarlos de cara al futuro. En el caso del olivar, la erosión que sufre el terreno, debido a las prácticas tradicionales de cultivo, ha propiciado la implantación de cubiertas vegetales que se controlan mediante el uso de maquinaria, o bien con herbicidas. El inconveniente que conllevan estas prácticas y la inquietud por prácticas más sostenibles han favorecido el estudio del uso de animales para el pastoreo en los campos de olivos. El inconveniente es que las hojas de los olivos son un alimento muy atractivo para las cabras y ovejas y pueden dañar el árbol. Con la finalidad de que las cabras rechacen consumir hojas de olivo, se plantea la posibilidad de modificar su comportamiento alimentario, utilizando diferentes dosis de cloruro de litio (LiCl), 175 mg LiCl/kg PV y 200 mg LiCl/kg PV. Los resultados obtenidos en cabras murciano-granadinas muestran la posibilidad de generar aversión a las hojas de olivo, que se mantuvo durante catorce meses. La aversión fue más efectiva en el caso de las cabras que recibieron la dosis de 200 mg LiCl/kg PV
Social presence in the 21st Century: an adjustment to the Community of Inquiry framework
The Community of Inquiry framework, originally proposed by Garrison, Anderson and Archer (2000) identifies teaching, social and cognitive presences as central to a successful online educational experience. This article presents the findings of a study conducted in Uruguay between 2007 and 2010. The research aimed to establish the role of cognitive, social and teaching presences in the professional development of 40 English language teachers on Continuous Professional Development (CPD) programmes delivered in blended learning settings. The findings suggest that teaching presence and cognitive presence have themselves 'become social'. The research points to social presence as a major lever for engagement, sense-making and peer support. Based on the patterns identified in the study, this article puts forward an adjustment to the Community of Inquiry framework, which shows social presence as more prominent within the teaching and cognitive constructs than the original version of the framework suggests
Detecting myocardial salvage after primary PTCA: early myocardial contrast echocardiography versus delayed Sestamibi perfusion imaging.
Aversión condicionada a aroma de fresa en ovino
La neofobia alimentaria es un mecanismo adaptativo que permite aprender de las consecuencias postingestivas al ingerir un alimento nuevo (Provenza y Balph, 1988; Van Tien et al., 1999). Cuando un animal consume un alimento nuevo, comienza por pequeñas cantidades y, en caso de percibir una retroalimentación positiva, incrementa el consumo según su apetecibilidad (Thorhallsdottir et al., 1987). Si la retroalimentación es negativa, el animal asocia las características sensoriales del alimento (gusto, olfato, tacto y vista) con el malestar postingestivo, lo que genera aversión condicionada al alimento (Frutos et al., 2001; Manuelian et al., 2014). Aromas, sabores y flavores se utilizan habitualmente para estimular el consumo de alimento en ganadería. Así, corderos adaptados a aromas y/o flavores (i.e., cebolla, ajo, hierba) aumentaron el consumo de alimentos nuevos tratados con el mismo aroma o flavor (Provenza et al., 1995; Nolte y Provenza, 1992; Van Tien et al., 1999). Sin embargo, la generalización de la aversión mediante aromas, sabores o flavores ha sido poco estudiada. La aversión al agua con aroma de almendra, inducida en ratas mediante 190 mg LiCl /kg PV, fue menor que con sabor dulce (sacarina), pero se potenció al utilizar un alimento con aroma y sabor (Palmerino et al., 1980). Por otro lado, ovejas con aversión a harina de arroz con flavor a canela, utilizando 250 mg LiCl/kg PV, mostraron aversión a harina de trigo con el mismo flavor (Launchbaugh y Provenza, 1993). La generalización de la aversión se mantuvo al incorporar el aroma a canela en harina de soja (Launchbaugh y Provenza, 1993). El objetivo del presente estudio fue crear aversión condicionada a un concentrado utilizando aromas y LiCl, a fin de evaluar la capacidad del ganado ovino de generalizar la aversión a otros alimentos con un mismo aroma
Do rebreathing manoeuvres for non-invasive measurement of cardiac output during maximum exercise test alter the main cardiopulmonary parameters?
Background: Inert gas rebreathing has been recently described as an emergent reliable non-invasive method for cardiac output determination during exercise, allowing a relevant improvement of cardiopulmonary exercise test clinical relevance. For cardiac output measurements by inert gas rebreathing, specific respiratory manoeuvres are needed which might affect pivotal cardiopulmonary exercise test parameters, such as exercise tolerance, oxygen uptake and ventilation vs carbon dioxide output (VE/VCO2) relationship slope. Method: We retrospectively analysed cardiopulmonary exercise testing of 181 heart failure patients who underwent both cardiopulmonary exercise testing and cardiopulmonary exercise test+cardiac output within two months (average 16 \ub1 15 days). All patients were in stable clinical conditions (New York Heart Association I\u2013III) and on optimal medical therapy. Results: The majority of patients were in New York Heart Association Class I and II (78.8%), with a mean left ventricular ejection fraction of 31 \ub1 10%. No difference was found between the two tests in oxygen uptake at peak exercise (1101 (interquartile range 870\u20131418) ml/min at cardiopulmonary exercise test vs 1103 (844\u20131389) at cardiopulmonary exercise test-cardiac output) and at anaerobic threshold. However, anaerobic threshold and peak heart rate, peak workload (75 (58\u2013101) watts and 64 (42\u201390), p < 0.01) and carbon dioxide output were significantly higher at cardiopulmonary exercise testing than at cardiopulmonary exercise test+cardiac output, whereas VE/VCO2 slope was higher at cardiopulmonary exercise test+cardiac output (30 (27\u201335) vs 33 (28\u201337), p < 0.01). Conclusion: The similar anaerobic threshold and peak oxygen uptake in the two tests with a lower peak workload and higher VE/VCO2 slope at cardiopulmonary exercise test+cardiac output suggest a higher respiratory work and consequent demand for respiratory muscle blood flow secondary to the ventilatory manoeuvres. Accordingly, VE/VCO2 slope and peak workload must be evaluated with caution during cardiopulmonary exercise test+cardiac output
Aplicació de l'aversió condicionada a l'olivera en cabres
Cada dia l'agricultura incorpora noves pràctiques més respectuoses amb el medi ambient intentant aprofitar millor els recursos naturals i preservar-los de cara al futur. En el cas de l'oliverar, l'erosió que pateix el sòl, a causa de les pràctiques tradicionals de conreu, ha propiciat la implantació de cobertes vegetals que es controlen mitjançant l'ús de maquinària, o bé amb herbicides. L'inconvenient que comporten aquestes pràctiques i la inquietud per pràctiques més sostenibles han afavorit l'estudi de l'ús de bestiar per pasturar els camps d'oliveres. L'inconvenient és que les fulles de les oliveres són un aliment molt atractiu per a cabres i ovelles i poden malmetre l'arbre. Amb la finalitat que les cabres rebutgin menjar fulles d'olivera, es planteja la possibilitat de modificar el seu comportament alimentari, utilitzant diferents dosis de clorur de liti (LiCl), 175 mg LiCl/kg PV i 200 mg LiCl/kg PV. Els resultats obtinguts en cabres murcianogranadines mostren la possibilitat de generar aversió a les fulles d'olivera, que es va mantenir durant catorze mesos. L'aversió va ser més efectiva en el cas de les cabres que van rebre la dosi de 200 mg LiCl/kg PV
Student Satisfaction and Performance in an Online Teacher Certification Program
The article presents a study which demonstrates the effectiveness of an online post baccalaureate teacher certification program developed by a Wisconsin university. The case method approach employing multiple methods and multiple data sources were used to investigate the degree to which pre-service teachers were prepared to teach. It was concluded that the study supports online delivery as an effective means of teacher preparation, but it was limited in the number of students followed into their first year of teaching
Neutrophil-to-Lymphocyte Ratio Predicts Prognosis in Patients with Chronic Coronary Heart Disease
Purpose: A relationship between blood cell count and survival has been observed both in healthy individuals and in patients with stable angina, unstable angina, myocardial infarction or heart failure. We tested the hypothesis that a complete blood count with subfraction concentrations would provide prognostic information in patients with chronic coronary heart disease (CHD), and that this information is additive to a standard diagnostic work-up. Methods: We prospectively examined 2370 consecutive patients with chronic CHD, defined by a > 50% stenosis at coronary angiography and/or history of myocardial infarction (MI). We examined the association between complete blood count, clinical variables and future cardiac events (cardiac death and non-fatal MI). Results: During follow-up (median 46 months), 147 patients (6.2%) died of cardiac causes and 81 (3.4%) experienced a non-fatal MI. Using univariate analysis, reduced hematocrit (< 36% if male and < 40% if female) and a neutrophil-to-lymphocyte (N/L) ratio > 2.42, but not white blood cell count and platelet count, were significantly associated with a reduced cardiac event-free survival (P < 0.001 and P <0.0001, respectively). The impact of anemia and high N/L ratio on survival persisted after adjustment for age, diabetes mellitus, left ventricular ejection fraction and angiographic extent of coronary atherosclerosis. The negative prognostic impact of a high N/L ratio persisted even after adjustment for both clinical variables and other routine laboratory variables (risk ratio: 1.57, 95% confidence interval: 1.19 to 2.08, p = 0.0014). Conclusion: An elevated N/L ratio is a significant predictor of adverse prognosis in patients with chronic CHD
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