Will global warming affect the distribution and abundance of the sweetpotato butterfly Acraea acerata Hew. in Africa?

In tropical Africa, the sweetpotato butterfly Acraea acerata, is a major endemic pest of sweetpotato (Ipomoea batatas (L.) Lam). Outbreaks of A. acerata are reported by farmers in Uganda to be more frequent than in the past 10 years. We therefore hypothesise that global warming may be responsible for this increased risk of outbreaks and abundance (damage potential). We used the Insect Life Cycle Modelling (ILCYM) software to develop temperature-based phenology models and applied three risk indices (establishment-, generation, and activity index) in a geographic information system (GIS) to map potential establishment, abundance and spread on global, regional and national scales. For current temperature conditions (year 2000) interpolated WorldClim data were used and for future climates (year 2050) downscaled data of the SRES-A1B scenario were applied

Early star formation traced by the highest redshift quasars

The iron abundance relative to alpha-elements in the circumnuclear region of quasars is regarded as a clock of the star formation history and, more specifically, of the enrichment by SNIa. We investigate the iron abundance in a sample of 22 quasars in the redshift range 3.0<z<6.4 by measuring their rest frame UV FeII bump, which is shifted into the near-IR, and by comparing it with the MgII 2798 flux. The observations were performed with a device that can obtain near-IR spectra in the range 0.8-2.4 um in one shot, thereby enabling an optimal removal of the continuum underlying the FeII bump. We detect iron in all quasars including the highest redshift (z=6.4) quasar currently known. The uniform observational technique and the wide redshift range allows a reliable study of the trend of the FeII/MgII ratio with redshift. We find the FeII/MgII ratio is nearly constant at all redshifts, although there is marginal evidence for a higher FeII/MgII ratio in the quasars at z~6. If the FeII/MgII ratio reflects the Fe/alpha abundance, this result suggests that the z~6 quasars have already undergone a major episode of iron enrichment. We discuss the possible implications of this finding for the star formation history at z>6. We also detect a population of weak iron emitters at z~4.5, which are possibly hosted in systems that evolved more slowly. Alternatively, the trend of the FeII/MgII ratio at high redshift may reflect significantly different physical conditions of the circumnuclear gas in such high redshift quasars.Comment: Replaced to match the accepted version (ApJL in press), 5 page

Chiral molecular films as electron polarizers and polarization modulators

Recent experiments on electron scattering through molecular films have shown that chiral molecules can be efficient sources of polarized electrons even in the absence of heavy nuclei as source of a strong spin-orbit interaction. We show that self-assembled monolayers (SAMs) of chiral molecules are strong electron polarizers due to the high density effect of the monolayers and explicitly compute the scattering amplitude off a helical molecular model of carbon atoms. Longitudinal polarization is shown to be the signature of chiral scattering. For elastic scattering, we find that at least double scattering events must take place for longitudinal polarization to arise. We predict energy windows for strong polarization, determined by the energy dependences of spin-orbit strength and multiple scattering probability. An incoherent mechanism for polarization amplification is proposed, that increases the polarization linearly with the number of helix turns, consistent with recent experiments on DNA SAMs.Comment: 5 Pages, 4 figure

Shear Modulus of an Elastic Solid under External Pressure as a function of Temperature: The case of Helium

The energy of a dislocation loop in a continuum elastic solid under pressure is considered within the framework of classical mechanics. For a circular loop, this is a function with a maximum at pressures that are well within reach of experimental conditions for solid helium suggesting, in this case, that dislocation loops can be generated by a pressure-assisted thermally activated process. It is also pointed out that pinned dislocations segments can alter the shear response of solid helium, by an amount consistent with current measurements, without any unpinning.Comment: 5 pages, 3 figure

Effect of cane variety, washing and endpoint temperature on the quality of granulated "panela" sugarcane

Granulated "panela" sugarcane is a new presentation for the "papelon" (unrefined cane sugar), handmade under non-standard processing conditions that result in a product of variable quality, but with advantages over the traditional block presentation. This study evaluated the effect of two varieties of sugar cane (Puerto Rico 61632 and Mayari 5514), of their washing prior to juice extraction, and of the endpoint temperature (123 and 128 degrees C) on the quality, of the granulated "panela" cane sugar made in a pilot-plant. Moisture, reducing sugars, pH, total soluble solids, color (L, a and b) and insoluble solids were measured. The variety influenced significantly (p <= 0.05) the content of reducing sugars, color and pH. The "panela" cane sugar made with the Mayari 5514 variety had lower content Of reducing sugars (7.20%), lighter color (L=73.98) and higher pH (6.09). With washed cane, a lower content of reducing sugars was obtained (7.92%), but it did not have a significant effect on the insoluble solids. The endpoint temperature affected only the color, resulting at 123 degrees C in "panela" cane sugars of lighter color and with a lower intensity of red hues. It is concluded that in order to obtain a product of uniform quality, it is necessary to control variables such as the cane variety and the endpoint temperature.33859860