A study of patchiness in mid-season dairy pastures : consequences and control : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science at Massey University

There is interest among some dairy farmers in increasing herbage intake of cows during spring by increasing pasture cover but without compromising pasture quality into the summer. "Late control" is a grazing management strategy developed in Massey University that meets those requirements (Matthews et al., 1996). In addition, it has been demonstrated in previous trials that Late control increases pasture production in the summer-autumn period by increasing ryegrass tillering vigour. Late control requires a period of lax grazing during spring to allow some reproductive growth development on ryegrass pastures, which is then controlled by hard grazing in late spring before anthesis. However, patchiness may develop in Late control during the lax grazing period when the herbage allowance is high. The objectives for the present experiment were to compare the pasture characteristics under Late control and conventional "Early control" spring management strategies in December-January, with particular reference to the consequences of vegetation heterogeneity to pasture production and utilisation over this period, and to discuss the implications to spring grazing management. The experiment involved detailed studies on three paddocks chosen from each of two farmlets of 22 paddocks used for a system trial comparing Early and Late control spring management on herds of 120 cows. Herbage mass distributions were estimated by taking 200 capacitance meter readings at random on each paddock. Relationships between herbage mass and utilisation and accumulation were estimated by using two 30 m permanent transects in each paddock. To determine botanical composition and tiller population variability within a sward, five tall patches and five short patches were sampled in each paddock. Paddocks in Late control before the control phase in December had more herbage mass than paddocks in Early control (3600 vs. 5000 kg DM/ha), but the variability of herbage mass was similar (1000 vs. 1000, standard deviation in kg DM/ha). The skewness of the herbage mass distribution was positive but greater in Early control than in Late control (0.57 vs. 0.32). Botanical composition was similar between treatments and within paddocks. Pasture morphology showed tiller size-density compensation in both treatments. Pasture characteristics in late control were not an impediment for efficient pasture removal in late control and more herbage was harvested than in Early control (1900 vs. 1000 kg DM/ha), although herbage allowance was greater in Early control. Short patches in both treatments were defoliated in less proportion than tall patches, but in Late control the proportion of short patches was less than in Early control. Therefore, low herbage mass and greater proportion of short patches in Early control had a negative effect on total herbage utilisation. Harvesting efficiency was controlled on Late control paddocks to avoid limitations to herbage intake, and the skewness of the distribution of herbage mass after grazing increased compared to Early control, as well as the proportion of tall poorly utilised patches. Topping of pastures after grazing was effective in removing poorly utilised material and in decreasing patchiness in January. In January, Late control paddocks had more herbage mass, but less patchiness than Early control paddocks (6300 vs. 4700 kg DM/ha). Sward characteristics were affected by treatment, and in general Late control increased ryegrass content and its leafiness during January compared to Early control. In January, herbage utilisation was greater in Late control than in Early control (3000 vs. 1700 kg DM/ha). It was concluded that because Late control had greater responses in tall patches, the objective should be to modify management to a longer rotation length before controlling reproductive growth in late spring, to allow a greater proportion of the sward to achieve high herbage mass. The combination of grazing and topping of pastures gave high herbage intakes and effective pasture control. More pasture was produced in Late control than in Early control and the rotation length can also be increased during the summer in Late control, which may benefit further ryegrass tillering

Strengthening rural value chains in Latin America

Global actors can interact along local value chains through international trade and foreign direct investment flows. By leveraging the value-chain approach for rural areas, recent policies have led to economic and social upgrading in Latin America, writes Ramón Padilla Pérez (UN Economic Commission for Latin America and the Caribbean)

The role of parenting styles on behavior problem profiles of adolescents

Parental behavior is one of the most influential factors on the development of adolescent externalizing and internalizing behavior problems. These behavioral problems are closely related and often co-occur. The objectives of this work were: (i) to identify adolescents profiles according to their behavior problems; (ii) to explore individual, family, and social characteristics associated with these profiles; and (iii) to analyze the potential role of parenting styles in belonging to adolescents’ profiles. A total of 449 Spanish adolescents (223 from families declared at-risk and enrolled in Child Welfare Services and 226 from families from the general population) participated in this study. The analyses revealed three profiles of adolescents based on external and internal behavior problems (adjusted, external maladjustment, and internal maladjustment). Parenting styles explained the adolescents’ belonging to different profiles, in which the indulgent style was the most favorable in general terms. The distinctive role of parenting styles on two types of maladjustment profiles was confirmed. The relationship between parenting styles and adolescent adjustment is a key component that should be included in interventions according to adolescents’ behavior problem profiles. Furthermore, the results shed light on the need that family interventions are complemented with individualized interventions with adolescents that accumulate stressful life events.Ministerio de Economía y Competitividad EDU2013-41441-

El Laboratorio Clínico en la mejoría continua de la calidad

El Laboratorio Clínico en la mejoría continua de la calida

Prey size selection of insular lizards by two sympatric predatory bird species

6 pages, 1 figure, 1 table.Size-related selection of insular lizards by two sympatric predatory bird species (Southern Grey Shrike and Eurasian Kestrel) was studied in an arid insular environment. The endemic lizard genus Gallotia was a key resource in the diet of both predators, constituting more than 50% of the total biomass. Shrikes captured smaller lizards than kestrels during all seasons (mean snout-vent length (SVL): 7.4 ± 1.9 vs. 9.4 ± 2.1 cm respectively), presenting a sequential use of lizard sizes and avoiding potential competition. On the other hand, shrikes and kestrels showed the same seasonal variation pattern, capturing the largest lizards during their breeding periods (spring). Considering lizard availability, shrikes displayed less selective predation than kestrels in all seasons. Shrikes positively selected the medium lizard size (SVL: 5-10 cm) during the nestling period, but negatively selected the small lizard size (SVL: < 5 cm) in autumn and winter, probably due to an explosion of juvenile lizards. Lastly, kestrels appeared to be more selective, negatively choosing the small lizard size but positively selecting the largest ones all the year round (SVL: > 10 cm).This research was supported by grants to David P. Padilla and Patricia Marrero from the Canarian Government and Proyectos Intramurales Especiales (2004 3 0E 169) of the Spanish National Scientific Research Council, respectively. It was also partially financed by the project PI042004/037 (Consejería de Educación, Cultura y Deportes, Gobierno de Canarias), which are partially supported by Feder funds from the European Union

Un estudio descriptivo de la vivencia de la parentalidad en usuarias de Servicios Sociales

Este estudio se centra en describir la vivencia de la parentalidad en familias usuarias de servicios sociales. Concretamente, se analizan diferentes dimensiones como la percepción de control o eficacia y la satisfacción o el estrés parental. Además, se toman en consideración prácticas parentales como la responsividad y el control psicológico para su análisis. Se ha contado con una muestra de 109 madres de familias en riesgo con un expediente abierto en servicios sociales, y con la información facilitada por los profesionales que las apoyan. En esta muestra, con un perfil demográfico y económico caracterizado por la precariedad, se observó un alto nivel de estrés y sentido de eficacia, así como un locus de control parental externo y una moderada satisfacción como madre. Los análisis efectuados evidenciaron que un bajo estrés parental, un locus de control más interno, un alto sentido de eficacia y un sentimiento de satisfacción con el rol, se relacionaron con altas puntuaciones de responsividad. Por otro lado, un locus de control más externo y una baja satisfacción con el rol parental se asociaron con un alto control psicológico. Se discute la importancia de considerar estas variables como claves para trabajar con las familias.This study describes the experience of parenting in families assisted by child and family social service programs. Specifically different dimensions such as locus of control, parental efficacy and satisfaction or parenting stress were analyzed. In addition, parental practices such as responsiveness and psychological control are considered. A sample of 109 mothers of at-risk families and the professionals who support them were included. In this sample, with a demographic and economic profile characterized by precariousness, a high level of stress and sense of efficacy was observed, as well as an external locus of parental control and a moderate satisfaction as a mother. Relationships between parental dimensions and parental practices were observed. The analyzes showed that, in one hand, a lower parental stress, an internal parental locus of control, a higher sense of efficacy and parental satisfaction, were related to higher scores of responsiveness. On the other hand, an external locus of control and a lower parental satisfaction were associated with a higher psychological control. The importance of considering these variables as keys to work with families is discussed

Rho GTPases: regulation of cell polarity and growth in yeasts

11 páginas, 4 figuras, 1 tabla.-- El pdf del artículo es la versión post-print.Eukaryotic cells display a wide range of morphologies important for cellular function and development. A particular cell shape is made via the generation of asymmetry in the organization of cytoskeletal elements, usually leading to actin localization at sites of growth. The Rho family of GTPases is present in all eukaryotic cells, from yeast to mammals, and their role as key regulators in the signalling pathways that control actin organization and morphogenetic processes is well known. In the present review we will discuss the role of Rho GTPases as regulators of yeasts' polarized growth, their mechanism of activation and signalling pathways in Saccharomyces cerevisiae and Schizosaccharomyces pombe. These two model yeasts have been very useful in the study of the molecular mechanisms responsible for cell polarity. As in other organisms with cell walls, yeast's polarized growth is closely related to cell-wall biosynthesis, and Rho GTPases are critical modulators of this process. They provide the co-ordinated regulation of cell-wall biosynthetic enzymes and actin organization required to maintain cell integrity during vegetative growth.Work in the authors’ laboratory is supported by the Direcci-on General de Investigación, MICINN, Spain [grant number BFU2007-60675]; and the Junta de Castilla y León [grant number GR231].Peer reviewe

DC-Voltage-Ratio Control Strategy for Multilevel Cascaded Converters Fed With a Single DC Source

Recently, a multilevel cascaded converter fed with a single DC source has been presented. An analysis of the steady-state working limits of this type of converter is presented in this paper. Limits of the maximum output voltage and the minimum and maximum loading conditions for stable operation of the converter are addressed. In this paper, a way to achieve any DC voltage ratio (inside the stable operation area of the converter) between the H-bridges of the single-DC-source cascaded H-bridge converter is presented. The proposed DC-voltage-ratio control is based on a time-domain modulation strategy that avoids the use of inappropriate states to achieve the DC-voltage-ratio control. The proposed technique is a feedforward-modulation technique which takes into account the actual DC voltage of each H-bridge of the converter, leading to output waveforms with low distortion. In this way, the dc voltage of the floating H-bridge can be controlled while the output voltage has low distortion independently of the desired DC voltage ratio. Experimental results from a two-cell cascaded converter are presented in order to validate the proposed DC-voltage-ratio control strategy and the introduced concepts.Ministerio de Ciencia y Tecnología TEC2006-03863Junta de Andalucía EXC/2005/TIC-117

THE CYCAD SCALE, AULACASPIS YASUMATSUI TAKAGI (HOMOPTERA: DIASPIDIDAE): A NEW INVASIVE PEST TO PUERTO RICO

THE CYCAD SCALE, AULACASPIS YASUMATSUI TAKAGI (HOMOPTERA: DIASPIDIDAE): A NEW INVASIVE PEST TO PUERTO RIC