Effect of Fungicide Spray Cover on Botrytis Cinerea Infection in Grape Bunches

The effect of fungicide spray cover on Botrytis cinerea infection in grape bunches was determined. Bunches were sprayed at pea size and bunch closure with different volumes of a mixture of fenhexamid and a yellow fluorescent pigment, and the percentage fluorescent pigment coverage on pedicels was determined. Bunches were subsequently dusted with dry airborne conidia of B. cinerea in a settling tower and incubated for 24 h at high relative humidity (98%). Infection was determined by estimating the amount of B. cinerea infections on susceptible bunch parts (pedicel, receptacle and rachis) with isolations onto paraquat (herbicide) and Kerssies (B. cinerea selective) mediums.  Linear regressions for the part × stage combinations of percentage B. cinerea incidence on different bunchparts were fitted on mean coverage levels. An increase in spray cover caused linear reductions in levels of B. cinerea on bunch parts. Higher B. cinerea incidences were recorded at pea size. Furthermore, higher B. cinerea incidences were found on paraquat medium for both stages, than on Kerssies medium. The information gathered from this study will be used to facilitate future determination of minimum effective coverage levels for effective B. cinerea control in grape bunches

Enrolment in Medieval English Government: Sickness or Cure?

In the Middle Ages, rolls were ubiquitous as a writing support. While scholars have long examined the texts and images on rolls, they have rarely taken the manuscripts themselves into account. This volume readdresses this imbalance by focusing on the materiality and various usages of rolls in late medieval England and France. Researchers from England, France, Germany and Singapore demonstrate in 11 contributions how this approach can increase our understanding of the rolls and their contents, as well as the contexts in which they were produced and used

Towards an improved understanding of eta --> gamma^* gamma^*

We argue that high-quality data on the reaction $e^+e^-\to \pi^+\pi^-\eta$ will allow one to determine the double off-shell form factor $\eta \to \gamma^*\gamma^*$ in a model-independent way with controlled accuracy. This is an important step towards a reliable evaluation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. When analyzing the existing data for $e^+e^- \to \pi^+\pi^-\eta$ in the range of total energies $1\text{GeV}^2<Q_2^2<(4.5\text{GeV})^2$, we demonstrate that the double off-shell form factor $F_{\eta\gamma^*\gamma^*}(Q_1^2,Q_2^2)$ is consistent with the commonly employed factorization ansatz at least for $Q_1^2<1\text{GeV}^2$, if the effect of the $a_2$ meson is taken into account. However, better data are needed to draw firm conclusions.Comment: 7 pages, 3 figure

Spillover Effects in Police Use of Force

We study the link between officer injuries-on-duty and the force-use of their peers using a network of officers who, through a random lottery, began the police academy together. We find that peer injuries-on-duty increase the probability of using force by 7%. The effect is concentrated in a narrow time window near the event and is not associated with significantly lower injury risk to the officer. Complaints of improper searches and failure to provide service also increase after peer injuries, suggesting that the increase in force might be driven by heightened risk aversion

The galactic center black hole as a possible retro-lens for the S2 orbiting star

Holz & Wheeler (\cite{hw}) have recently proposed that a Schwarzschild black hole may act as a retro-lens which, if illuminated by a powerful light source, deflects light ray paths to large bending angles and a series of luminous arcs (or rings in the case of aligned objects) centered on the black hole may form. Obviously, the most convenient geometry to get retro-lensing images would be that of a very bright star close to a massive black hole, say the putative $\sim 4\times 10^6$ M$_{\odot}$ black hole at the galactic center. Recent observations of the galactic center region in the $K$-band have revealed the presence of a very bright main sequence star (labelled S2) with mass $\sim 15$ M$_{\odot}$ orbiting at close distance (130-1900 AU) from Sgr A$^*$. The relatively vicinity of S2 to the central massive black hole may offer a unique laboratory to test the formation of retro-lensing images. The next generation of space-based telescopes in the $K$-band (like NGST) may have high enough limiting magnitude necessary to observe such retro-lensing images.Comment: 4 pages, 2 Postscript figures, accepted for pubblications on Astronomy and Astrophysic

SAE Small Vehicle Lifts

The SAE (Society for Automotive Engineers) vehicle teams at Cal Poly need an easy way to access the undersides of their vehicles to facilitate maintenance and servicing. The purpose of this project was to provide a solution that could lift the vehicles effectively and safely from above so that the underside of the vehicles can be accessed, as well as elevating the vehicles to an ergonomic working height. Design specifications were determined based off each vehicle’s requirements in addition to what the team intends to do with their suspended vehicle. After several concept iterations, the team decided to purchase an engine hoist and replace the hydraulic cylinder with a fixed tube and construct a custom transmission thereby turning the engine hoist into a crane mechanism that can be operated easily without concerns of reliability. The team constructed a total of three lifts, each with different specifications, for the Baja, Formula, and F2000 cars. Material testing was done to verify that the unknown material of the purchased lifts was strong enough to support the loading, as well as final load testing by lifting a vehicle to its designed height

Holocene Dynamics of Temperate Rainforests in West-Central Patagonia

Analyses of long-term ecosystem dynamics offer insights into the conditions that have led to stability vs. rapid change in the past and the importance of disturbance in regulating community composition. In this study, we (1) used lithology, pollen, and charcoal data from Mallín Casanova (47°S) to reconstruct the wetland, vegetation, and fire history of west-central Patagonia; and (2) compared the records with independent paleoenvironmental and archeological information to assess the effects of past climate and human activity on ecosystem dynamics. Pollen data indicate that Nothofagus-Pilgerodendronforests were established by 9,000 cal yr BP. Although the biodiversity of the understory increased between 8,480 and 5,630 cal yr BP, forests remained relatively unchanged from 9,000 to 2,000 cal yr BP. The charcoal record registers high fire-episode frequency in the early Holocene followed by low biomass burning between 6,500 and 2,000 cal yr BP. Covarying trends in charcoal, bog development, and Neoglacial advances suggest that climate was the primary driver of these changes. After 2,000 cal yr BP, the proxy data indicate (a) increased fire-episode frequency; (b) centennial-scale shifts in bog and forest composition; (c) the emergence of vegetation-fire linkages not recorded in previous times; and (d) paludification in the last 500 years possibly associated with forest loss. Our results therefore suggest that Nothofagus-Pilgerodendrondominance was maintained through much of the Holocene despite long-term changes in climate and fire. Unparalleled fluctuations in local ecosystems during the last two millennia were governed by disturbance-vegetation-hydrology feedbacks likely triggered by greater climate variability and deforestation

Spectral Curves and Localization in Random Non-Hermitian Tridiagonal Matrices

Eigenvalues and eigenvectors of non-Hermitian tridiagonal periodic random matrices are studied by means of the Hatano-Nelson deformation. The deformed spectrum is annular-shaped, with inner radius measured by the complex Thouless formula. The inner bounding circle and the annular halo are stuctures that correspond to the two-arc and wings observed by Hatano and Nelson in deformed Hermitian models, and are explained in terms of localization of eigenstates via a spectral duality and the Argument principle.Comment: 5 pages, 9 figures, typographical error corrected in reference