302 research outputs found
Feral goats in south-western Queensland: a permanent component of the grazing lands
Feral goats were harvested in south-western Queensland at four sites under two regimes (opportunistic harvesting and sustained control). We assessed how this impacted on their contribution to total grazing pressure, on soil and pasture conditions and on the economics of goat management. The population impact was not consistent across sites with the same treatment, with 62% and 84% reductions in numbers in the two northern sites (one opportunistic harvesting site and one sustained control site) while numbers in the southern sites essentially remained the same. The contribution of goats to grazing pressure ranged from 3 to 30%; kangaroos contributed 16–36%; and livestock contributed 37–72%. Harvest rates of feral goats calculated for each of the sites ranged from 17 to 41%. There was no consistent relationship between population changes and the harvest rates. Seasonal conditions had greater influence on pasture and soil conditions than did changes in feral goat populations. The average cost of mustering goats (based on 34 operations) was 2.08 per head. This compared with on-farm prices of 25 per head in 1997. Personal circumstances and preferences of individual landholders were the key determinant of the level of control undertaken. Variability in price contributed to landholders being apprehensive about the viability of the goat industry. There are few simple tools available for landholders to estimate feral goat numbers and this makes effective management of total grazing pressure difficult
Direct demonstration of an HLA-DR allotypic determinant on the low molecular weight (beta) subunit using a mouse monoclonal antibody specific for DR3
A murine monoclonal antibody directed against a human B cell surface antigen with the characteristics of HLA-DR is described. The antigen detected is tightly linked to HLA and is correlated with the alloantigen HLA-Dw/DR3. Reactivity with a fraction of Dw/DRw6 cells is also observed. The determinant recognized by this antibody has been shown to be present on the smaller molecular weight β subunit of the HLA-DR antigen
New Approach for Boat Motion Analysis in Rowing
In rowing, the study of the movement of the boat and of the rower in the boat is difficult. Indeed, the shell is quite narrow and fragile and it is impossible to use the classical apparatus for physiological and biomechanical analysis.
For this reason, the physiological studies of rowers (cardiac and pulmonary parameters) have been more easily realised on specific and non specific ergometers (see Hagerman for an extensive review 1984): it is well known now, that rowers have exceptional aerobic possibilities and also use anaerobiosis for the start and the final part of the race (Hagerman 1984).
In contrast, only a few publications deal with the movement of the boat and the rower. The velocity of the boat at different stroke rates (Martin and Bernfield 1980), the angular velocities of various articulations of the rowers (Nelson and Widule 1983) were studied by kinematic analysis.
Though this technique is very useful, it does not catch the movements behind the subjects and is of no use to record physiological and mechanical parameters (Ishiko 1967).
Some authors used DC recorder placed in a motor boat following the racing shell to record different parameters (Baird and Soroka 1952; Di Prampero 1971; Celentano 1974). But, this technique is not practical because of the need of a second operator to keep the cables out of the water.
With the miniaturization, Ishiko proposed and used multichanneltelemetry to record the force of the rower and the acceleration of the boat (Ishiko 1967; Ishiko 1971). Schneider also used the same technique to record the force of the rower in the boat (Schneider 1978).
Though this technique is excellent and powerful, it is also very expensive and quite sophisticated.
Our goal was thus to take advantage of the miniaturization of the elements and to build and use a recorder and transducers that can be placed into the boat to record the acceleration of the boat and the propulsive force of the rower
The acceptance of GM food with health benefits by consumers in Germany: a structural equation model
152 p.
Georg-August-University of Göttingen, GermanyA study was carried out in Germany in order to assess the consumers’ acceptance
of GM foods with health benefits. Employing a Structural Equation Model (SEM), it was
determined what factors influence over the acceptance of GM food, and how do these
factors interact among them. The sample consisted in 183 students from the University
of Göttingen, who were approached using a “mall interception” methodology in the
University’s principal lunch room. Respondents were asked to state their willingness to
consume three different hypothetical GM products (GM yoghurt drinks, GM bread, and
GM eggs) that contained Omega-3 fatty acids, which were described as helping reduce
the risk of having a coronary heart disease, and costing the same as their traditional
counterpart. Results show that the inclusion of a health benefit increases the acceptability
of GM foods, when its source does not involve animals like in the case of the GM eggs.
In addition, the SEM model shows that there are two factors that have a direct influence
over the acceptance of GM food with health benefits, which are the respondents’ attitude
towards biotechnology, and their price consciousness. There were other factors that also
have an effect over the acceptability of GM foods in an indirect way, through their
influence over the attitude towards biotechnology. These indirect factors were the
respondents’ health consciousness, their attitude towards organic, and their attitude
towards functional foods. These findings should be validated using a sample that is
representative of the general consumers in Germany
Flow around individual Taylor bubbles rising in stagnant CMC solutions: PIV measurements
The flow around single Taylor bubbles rising in non-Newtonian solutions of Carboxymethylcellulose (CMC) polymer was studiedusing a simultaneous technique employing particle image velocimetry (PIV) and shadowgraphy. This technique solved previousproblems on finding the correct position of the bubble interface. Solutions of different polymer weight percentage, varying from0.1 to 1.0 wt% were used to cover a wide range of flow regimes. The rheological fluid properties and pipe dimension yieldedReynolds numbers between 4 and 254 and Deborah numbers between 0.012 and 0.402. The shape of the bubbles in the differentfluids was compared. The flow around the nose of the bubbles was found to be similar in all the studied conditions. Velocityprofiles in the liquid film around the bubble were measured. Different wake structures were found in the different solutionsstudied. With increasing viscosity, the wake flow varied from turbulent to laminar, being possible to observe a negative wake forthe higher polymer concentration solutions. A comparison between the different wake structures was made
Vroege bepaling van de effectiviteit van ALS-remmende herbiciden
MLHD, de methode om lage herbicide doseringen op maat en met controle op effectiviteit toe te passen is specifiek ontwikkeld voor fotosynthese-remmers. Telers ervaren de beperkte toepasbaarheid van de methodiek soms als bezwaar. Via onderzoek worden de mogelijkheden om MLHD te verbreden naar middelen met andere werkingsmechanismen verkend. In dit artikel wordt een overzicht gegeven van dergelijk onderzoek gericht op ALS(AcetoLactaatsynthase)-remmende herbicide
Formulacion y validacion de un modelo descriptivo de la evolucion del area foliar de maiz
Resumen (Spanish, English)42 p.La necesidad de disponer de una metodología científica simplificada y de carácter relativamente universal, destinada a describir la evolución del área foliar de plantas de maíz de diferentes precocidades a través de su ciclo, llevó a desarrollar este estudio, destinado a formular y validar un modelo para describir su crecimiento, cuando el cultivo se desarrolla en condiciones de campo. Para esto se utilizaron resultados originales provenientes de experimentos realizados en Chile, entre 1984 y 1997, en siembras ubicadas entre los paralelos 35 y 38° de latitud Sur (VII, VIII y IX Regiones). En ellos se evaluó los cambios de área foliar por planta (AFPP) con respecto al tiempo. Para la expresión de éste, se empleó la integral térmica (GDC). Ambas variables fueron transformadas a valores relativos, para generar modelos de desarrollo foliar que permitieran describir los cambios de AFPP con respecto a GDC. Esta metodología permite calcular densidades de población de siembra de híbridos de cualquier precocidad, al conocer el tiempo térmico requerido para que alcancen la superficie foliar máxima, la cual se logra cuando el cultivo acumula alrededor de un 45% de GDC, entre emergencia y madurez fisiológica. La función lineal que describe el desarrollo foliar en esta etapa es la siguiente: AFPP = 16,27 * GDC – 2.736. A partir de floración, el proceso de senescencia foliar está ligado a disponibilidad de nitrógeno, y factores genéticos, entre otros. Cuando el cultivo alcanza un 75% de su ciclo, el AFPP es del orden de 90 %, estado en el cual comienza una fase de senescencia acelerada, que muestra distintas tendencias,
gobernadas por los factores recién mencionados, cuando no median elementos limitantes del crecimiento de las plantas
Estimation of the individual residual risk of cervical cancer after vaccination with the nonavalent HPV vaccine
Background: The nonavalent HPV (9vHPV) vaccine is indicated for active immunisation of individuals from the age of 9 years against cervical, vulvar, vaginal and anal premalignant lesions and cancers causally related to vaccine HPV high risk types 16, 18, 31, 33, 45, 52 and 58, and to the HPV low risk types 6 and 11, causing genital warts. Objective: To estimate the lifetime risk (up to the age of 75 years) for developing cervical cancer after vaccinating a HPV naive girl (e.g. 9 to 12 years old) with the 9vHPV vaccine in the hypothetical absence of cervical cancer screening. Methods: We built Monte Carlo simulation models using historical pre-screening age-specific cancer incidence data and current mortality data from Denmark, Finland, Norway, Sweden and the UK. Estimates of genotype contribution fractions and vaccine efficacy were used to estimate the residual lifetime risk after vaccination assuming lifelong protection. Results: We estimated that, in the hypothetical absence of cervical screening and assuming lifelong protection, 9vHPV vaccination reduced the lifetime cervical cancer and mortality risks 7-fold with a residual lifetime cancer risks ranging from 1/572 (UK) to 1/238 (Denmark) and mortality risks ranging from 1/1488 (UK) to 1/851 (Denmark). After decades of repetitive cervical screenings, the lifetime cervical cancer and mortality risks was reduced between 2- and 4-fold depending on the country. Conclusion: Our simulations demonstrate how evidence can be generated to support decision-making by individual healthcare seekers regarding cervical cancer prevention
Characterization of silver particles in the stratum corneum of healthy subjects and atopic dermatitis patients dermally exposed to a silver-containing garment
Silver is increasingly being used in garments to exploit its antibacterial properties. Information on the presence of silver nanoparticles (AgNPs) in garments and their in vivo penetration across healthy and impaired skin from use is limited. We investigated the presence of AgNPs in a silver containing garment and in the stratum corneum (SC) of healthy subjects (CTRLs) and individuals with atopic dermatitis (AD). Seven CTRLs and seven AD patients wore a silver sleeve (13% Ag w/w) 8 h/day for five days on a forearm and a placebo sleeve on the other forearm. After five days, the layers of the SC were collected by adhesive tapes. The silver particles in the garment and SC were characterized by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX) and atomic force microscopy (AFM). AFM and SEM revealed the presence of sub-micrometre particles having a broad range of sizes (30\u2013500 nm) on the surface of the garment that were identified as silver. On the SC tapes collected from different depths, aggregates with a wide range of sizes (150 nm\u20132 \u3bcm) and morphologies were found. Most aggregates contained primarily silver, although some also contained chlorine and sulfur. There was no clear difference in the number or size of the aggregates observed in SC between healthy and AD subjects. After use, AgNPs and their aggregates were present in the SC at different depths of both healthy subjects and AD patients. Their micrometre size suggests that aggregation likely occurred in the SC
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