Towards Grower-friendly Apple Crop Thinning by Tree Shading

Light management with shading nets, which reduce sunlight by 74%, might be an alternative to chemicals commonly used for thinning on apple trees. To study the effect of shading on crop load and fruit quality, trials were conducted in field experiments with the cultivars Golden Delicious and Elstar in 2006. Trees were either covered 25 days after full bloom (DAFB) with a net during three days, or until the peak of fruit fall, observed after seven days shading. Ideal time length for optimal crop yield was seven days shading for Elstar and three days shading for Golden Delicious. Alternate bearing could be decreased as flower initiation counts the following year showed. In both experiments, inner quality of fruit such as sugar and firmness showed good values at optimal shading duration compared with chemical + hand thinning. In 2007, a second field trial was conducted with cultivars Golden Delicious and Topaz to study the time period for shading in further detail. Shading was done for three days at 19, 26 and 33 DAFB using two net types (three- and two-meter-net width, covering the trees entirely or only down to 50 cm above ground). For Golden Delicious, shading after 19 and 26 days reduced fruits per 100 flower cluster to the same extent as with chemical + hand thinning. There was no difference between the two net types. For Topaz, shading after 19 days showed the best results. Regarding inner quality of both cultivars, only sugar content for Golden Delicious could be significantly improved after 19 and 26 days shading. Further analyses are still under way (e.g. for acidity). This study is part of an effort for increasing European consumption with fruit from sustainable production systems, the ISAFRUIT-EU-project

PPM-Extended (PPMX) - a catalogue of positions and proper motions

Aims: We build a catalogue PPM-Extended (PPMX) on the ICRS system which is complete down to a well-defined limiting magnitude and contains the best presently available proper motions to be suited for kinematical studies in the Galaxy. Methods: We perform a rigorous weighted least-squares adjustment of individual observations, spread over more than a century, to determine mean positions and proper motions. The stellar content of PPMX is taken from GSC 1.2 supplemented by catalogues like ARIHIP, PPM and Tycho-2 at the bright end. All observations have been weighted according to their individual accuracy. The catalogue has been screened towards rejecting false entries in the various source catalogues. Results: PPM-Extended (PPMX) is a catalogue of 18,088,920 stars containing astrometric and photometric information. Its limiting magnitude is about 15.2 in the GSC photometric system. PPMX consists of three parts: a) a survey complete down to R_U = 12.8 in the magnitude system of UCAC2; b) additional stars of high-precision proper motions, and c) all other stars from GSC 1.2 identified in 2MASS. The typical accuracy of the proper motions is 2mas/y for 66 percent of the survey stars (a) and the high-precision stars (b), and about 10 mas/y for all other stars. PPMX contains photometric information from ASCC-2.5 and 2MASS.Comment: 9 pages, 8 figures, accepted for publication in Astronomy and Astrophysic

Chasing Funding “To Eat Our Own Tail”: The Invisible Emotional Work of Making Social Change

This article presents findings from a multi-site study conducted in Montréal, QC, and Toronto, ON, Canada, on “social innovation” networks, focusing on the forms of emotional and relational work that many participants described. The article explores how these tasks related to how workers in the two nonprofit “backbone” organizations described their contributions to the impacts they hoped to make. The intersections of these forms of work and particular identities are framed within a feminist lens—when and how are these forms of relational work recognized or made invisible? This work is contextualized within neoliberal reforms, the restructuring of the state, and external funding requirements and how these determine what forms of work are deemed “impactful” in making significant social change around broad issues of homelessness and social exclusion.Cet article présente les résultats d’une étude multi-sites sur les réseaux « d’innovation sociale » menée à Montréal, QC et Toronto, ON, Canada, et met l’accent sur des formes de travail émotionnel et relationnel décrites par de nombreux participants. Les auteurs explorent la relation entre ces tâches et la manière dont les travailleurs de deux organismes à but non lucratif centraux décrivent leurs contributions aux impacts qu’ils espéraient avoir. Les intersections de ces travaux et des identités particulières s’inscrivent dans une perspective féministe—quand et comment les formes de travail relationnelles sont-elles reconnues ou rendues invisible? Cet article s’inscrit dans le cadre des réformes néolibérales, de la restructuration de l’État et des besoins des bailleurs de fonds externes, et comment ceux-ci déterminent quelles formes de travail sont considérées comme ayant un impact « décisif » sur le changement social important autour des grandes questions de l’itinérance et d’exclusion sociale

Optical control of coherent interactions between quantum dot electron spins

Coherent interactions between spins in quantum dots are a key requirement for quantum gates. We have performed pump-probe experiments in which pulsed lasers emitting at different photon energies manipulate two distinct subsets of electron spins within an inhomogeneous InGaAs quantum dot ensemble. The spin dynamics are monitored through their precession about an external magnetic field. These measurements demonstrate spin precession phase shifts and modulations of the magnitude of one subset of oriented spins after optical orientation of the second subset. The observations are consistent with results from a model using a Heisenberg-like interaction with microeV-strength.Comment: 5 pages, 4 figure

Electrical properties of breast cancer cells from impedance measurement of cell suspensions

Impedance spectroscopy of biological cells has been used to monitor cell status, e.g. cell proliferation, viability, etc. It is also a fundamental method for the study of the electrical properties of cells which has been utilised for cell identification in investigations of cell behaviour in the presence of an applied electric field, e.g. electroporation. There are two standard methods for impedance measurement on cells. The use of microelectrodes for single cell impedance measurement is one method to realise the measurement, but the variations between individual cells introduce significant measurement errors. Another method to measure electrical properties is by the measurement of cell suspensions, i.e. a group of cells within a culture medium or buffer. This paper presents an investigation of the impedance of normal and cancerous breast cells in suspension using the Maxwell-Wagner mixture theory to analyse the results and extract the electrical parameters of a single cell. The results show that normal and different stages of cancer breast cells can be distinguished by the conductivity presented by each cell. © 2010 IOP Publishing Ltd

Effect of pump-probe detuning on the Faraday rotation and ellipticity signals of mode-locked spins in InGaAs quantum dots

We have studied the Faraday rotation and ellipticity signals in ensembles of singly-charged (In,Ga)As/GaAs quantum dots by pump-probe spectroscopy. For degenerate pump and probe we observe that the Faraday rotation signal amplitude first grows with increasing the time separation between pump and probe before a decay is observed for large temporal separations. The temporal behavior of the ellipticity signal, on the other hand, is regular: its amplitude decays with the separation. By contrast, for detuned pump and probe the Faraday rotation and ellipticty signals both exhibit similar and conventional behavior. The experimental results are well described in the frame of a recently developed microscopic theory [Phys. Rev. B 80, 104436 (2009)]. The comparison between calculations and experimental data allows us to provide insight into the spectral dependence of the electron spin precession frequencies and extract the electron g-factor dependence on energy.Comment: 9 pages, 7 figure

QCD and electroweak corrections to WZ scattering at the LHC

We present the first computation of the full next-to-leading-order QCD and electroweak corrections to the WZ scattering process at the LHC. All off-shell, gauge-boson-decay, and interference effects are taken into account for the process $\mathrm{p} \mathrm{p} \to \mu^+\mu^-\mathrm{e}^+\nu_\mathrm{e} \mathrm{j} \mathrm{j} + X$ at the orders $\mathcal{O}{\left( \alpha_\mathrm{s} \alpha^6 \right)}$ and $\mathcal{O}{\left( \alpha^7 \right)}$. The electroweak corrections feature the typical Sudakov behaviour towards high energy and amount to $-16\%$ relative to the electroweak contribution to the integrated cross section. Moreover, the corrections induce significant shape distortions in differential distributions. The next-to-leading-order analysis of the quark- and gluon-induced channels is supplemented by a leading-order study of all possible contributions to the full 4\ell+2\mbox{jets} production cross section in a realistic fiducial phase-space volume

Relações de causa e efeito entre condições ambientais, urediniósporos e severidade de ferrugem-asiática da soja.

O objetivo deste trabalho foi estabelecer relações entre condições ambientais, o número de urediniósporos de Phakopsora pachyrhizi e a severidade da ferrugem-asiática-da-soja. Para quantificar urediniósporos de P. pachyrhizi, coletores foram instalados em campos de soja, em Itambé e Mandaguari, PR. Avaliações de severidade foram realizadas e dados climáticos foram coletados nos dois locais. As variáveis elaboradas foram: número de dias com umidade favorável (>60%), número de dias com temperatura favorável (18 a 32º C), preciptação acumulada e urediniósporos coletados. Uma variável baseada no controle químico também foi elaborada. Correlações entre as variáveis foram estimadas. A análise de trilha foi empregada para desdobrar as correlações. Cerca de 76% da variação das relações de causa e efeito entre as variáveis foi explicada pela análise de trilha. O número de dias para efetuar o controle químico teve efeito direto sob a severidade. O número de dias com temperatura favorável e as precipitações tiveram efeito indireto na severidade, atuando via manutenção de condições favoráveis de umidade

Biological Control of Sheep Parasites using Duddingtonia flagrans: Trials on Commercial Farms in Sweden

Trials were conducted on 3 commercial sheep farms in Sweden to assess the effect of administering spores of the nematode trapping fungus, Duddingtonia flagrans, together with supplementary feed to lactating ewes for the first 6 weeks from turn-out on pastures in spring. Also control groups of ewes, receiving only feed supplement, were established on all 3 farms. Groups were monitored by intensive parasitological investigation. The ewes and their lambs were moved in late June to saved pastures for summer grazing, the lambs receiving an anthelmintic treatment at this time. After approximately 6 weeks on summer pasture the lambs were weaned, treated a second time with anthelmintic, and returned to their original lambing pastures for finishing. Decisions as to when lambs were to be marketed were entirely at the discretion of the farmer co-operators. No difference in lamb performance was found between the two treatments on all three farms. This was attributed to the high levels of nutrition initially of the ewes limiting their post-partum rise in nematode faecal egg counts in spring, which in turn resulted in low levels of nematode infection on pastures throughout the autumn period. Additionally, pastures were of good quality for the lambs during the finishing period, so they grew at optimal rates as far as the farmers were concerned