Host age selection behaviour of Trichogramma aurosum Sugonjaev & Sorokina (Hymenoptera: Trichogrammatidae)

Host age selection in several German strains of Trichogramma aurosum Sugonjaev & Sorokina was examined in laboratory choice tests under direct observation for 90 min., in order to select candidate strains for attempts at controlling the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae). Experiments were conducted at room temperature by exposing combinations of two host ages (zero vs. 4 and 1 vs. 5-day old) to a single female wasp. Host age did not appear to affect the wasps parasitization behaviour, although they spent longer time drilling on old eggs (4 and 5 days old) compared with fresh ones (0 and 1 day old). This not necessarily means that they preferred fresh eggs over old ones, since both type of hosts were parasitized in the choice test. Possibly an increased mechanical resistance of the chorion of older eggs was responsible for the prolonged drilling time. Mean drumming time was independent of host age. Mean duration of drilling and drumming was in general longest in the first and last egg attacked by all T. aurosum strains tested and for all host ages. Drilling time consumed more than 80% of the mean handling time of all strains tested for all host ages, followed by resting and walking

Magnetic Corrections to π{\pi}-π{\pi} Scattering Lengths in the Linear Sigma Model

In this article we consider the magnetic corrections to ${\pi}$-${\pi}$ scattering lengths in the frame of the linear sigma model. For this we consider all the one loop corrections in the s, t and u channels, associate to the insertion of a Schwinger propagator for charged pions, working in the region of small values of the magnetic field. Our calculation relies on an appropriate expansion for the propagator. It turns out that the leading scattering length, $l = 0$ in the S-channel, increases for an increasing value of the magnetic field, in the isospin $I = 2$ case whereas the opposite effect is found for the $I = 0$ case. The isospin symmetry is valid because the insertion of the magnetic field occurs through the absolute value of the electric charges. The channel $I = 1$ does not receive any corrections. These results, for the channels $I = 0$ and $I = 2$ are opposite with respect to the thermal corrections found previously in the literature.Comment: 6 pages. arXiv admin note: text overlap with arXiv:0801.2176; new references were added; to appear in Phys. Rev.

Luminous HC3N line emission in NGC4418 - buried AGN or nascent starburst?

IRAM 30m observations reveal that the deeply obscured IR-luminous galaxy NGC4418 has a rich molecular chemistry - including unusually luminous HC3N line emission. We furthermore detect: ortho-H2CO 2-1, 3-2; CN 1-0, 2-1; HCO+, 1-0. 3-2, HCN 3-2, HNC 1-0, 3-2 (and tentatively OCS 12-11). The HCN, HCO+, H2CO and CN line emission can be fitted to densities of n=5 x 10E4 - 10E5 cm-3 and gas temperatures Tk=80-150 K. Both HNC and HC3N are, however, significantly more excited than the other species which requires higher gas densities - or radiative excitation through e.g. mid-IR pumping. The HCN line intensity is fainter than that of HCO+ and HNC for the 3-2 transition, in contrast to previous findings for the 1-0 lines where the HCN emission is the most luminous. We tentatively suggest that the observed molecular line emission is consistent with a young starburst, where the emission can be understood as emerging from dense, warm gas with an additional PDR component. We find that X-ray chemistry is not required to explain the observed mm line emission, including the HCN/HCO+ 1-0 and 3-2 line ratios. The luminous HC3N line emission is an expected signature of dense, starforming gas. A deeply buried AGN can not be excluded, but its impact on the surrounding molecular medium is then suggested to be limited. However, detailed modelling of HC3N abundances in X-ray dominated regions (XDRs) should be carried out. The possibility of radiative excitation should also be further investigatedComment: 7 pages, one eps figure, uses aa.cls, submitted to Astronomy and Astrophysic

Work integration enterprises as a job opportunities for people at risk of social exclusion

Las empresas de inserción son un recurso laboral poco conocido y tenido en cuenta en nuestra sociedad. No obstante, cumplen una importante función social que abarca la formación y orientación profesional y la inserción sociolaboral de las personas en riesgo de exclusión. Fueron muchos los hechos que hicieron resurgir las empresas de inserción en España impulsando la creación de una ley estatal que las regulara.En este estudio bibliográfico se pretende conocer los antecedentes de las empresas de inserción, su conceptualización, el desarrollo profesional y el proceso de inserción sociolaboral que realizan, el papel de los profesionales en los itinerarios de inserción, así como la labor específica que desarrollan cubriendo un vacío imposible de cubrir por los Servicios Públicos de Empleo. Tras la revisión bibliográfica, se concluye que los futuros profesionales de la educación deberían conocer estas empresas como posibles oportunidades laborales. Además, dar a conocer las empresas de inserción como una intervención práctica y eficaz para las personas en riesgo de exclusión social que, en muchas ocasiones, se encuentran desamparadas en el acceso al mercado laboral y a la sociedad.Work integration enterprises are little known work resources that are rarely taken into account in our society. However, they play an important social role which includes training, vocational guidance and socio-labour insertion of people at risk of exclusion. There were many facts that did emerge this companies in Spain promoting the creation of a State law that regulate them. This bibliographic study seeks to explain the background of the work integration enterprises, their conceptualization, professional development and the process of socio-labour insertion. Also, they perform the role of professionals in the itineraries of insertion and the specific work carried out covering a space impossible to cover by the public employment services. Following the literature review, it is concluded that future education professionals should be aware of these companies as potential job opportunities. In addition, to present work integration enterprises as a practical and effective intervention for people at risk of social exclusion which, often, are helpless in access to the labour market and society

La oficina del siglo XX. Oficina, Organización, Corporativo, Implantación, Equipamiento

La organización del trabajo dispone de herramientas que han sido ensayadas durante el siglo pasado y que muestran el engranaje de su funcionamiento y su resultado