Bounding the number of points on a curve using a generalization of Weierstrass semigroups

In this article we use techniques from coding theory to derive upper bounds for the number of rational places of the function field of an algebraic curve defined over a finite field. The used techniques yield upper bounds if the (generalized) Weierstrass semigroup [P. Beelen, N. Tuta\c{s}: A generalization of the Weierstrass semigroup, J. Pure Appl. Algebra, 207(2), 2006] for an $n$-tuple of places is known, even if the exact defining equation of the curve is not known. As shown in examples, this sometimes enables one to get an upper bound for the number of rational places for families of function fields. Our results extend results in [O. Geil, R. Matsumoto: Bounding the number of $\mathbb{F}_q$-rational places in algebraic function fields using Weierstrass semigroups. Pure Appl. Algebra, 213(6), 2009]

Resolving the molecular gas around the lensed quasar RXJ0911.4+0551

We report on high angular resolution observations of the CO(7-6) line and millimeter continuum in the host galaxy of the gravitationally lensed (z~2.8) quasar RXJ0911.4+0551 using the Plateau de Bure Interferometer. Our CO observations resolve the molecular disk of the source. Using a lens model based on HST observations we fit source models to the observed visibilities. We estimate a molecular disk radius of 1$\pm$0.2 kpc and an inclination of 69$\pm$6\deg, the continuum is more compact and is only marginally resolved by our observations. The relatively low molecular gas mass, $Mgas=(2.3\pm 0.5)\times 10^{9}$ Msolar, and far infrared luminosity, $LFIR=(7.2\pm 1.5) \times 10^{11}$ Lsolar, of this quasar could be explained by its relatively low dynamical mass, $Mdyn=(3.9\pm 0.9)\times 10^9$ Msolar. It would be a scaled-down version the QSOs usually found at high-z. The FIR and CO luminosities lie on the correlation found for QSOs from low to high redshifts and the gas-to-dust ratio ($45\pm 17$) is similar to the one measured in the z=6.4 QSO, SDSS J1148+5251. Differential magnification affects the continuum-to-line luminosity ratio, the line profile and possibly the spectral energy distribution.Comment: Accepted for publication in A&A, revised after language editin

The Canada-France High-z Quasar Survey: 1.2mm Observations

We report 250 GHz (1.2 mm) observations of a sample of 20 QSOs at redshifts 5.8<z<6.5 from the the Canada-France High-z Quasar Survey (CFHQS), using the Max-Planck Millimeter Bolometer (MAMBO) array at the IRAM 30-metre telescope. A rms sensitivity <~ 0.6 mJy was achieved for 65% of the sample, and <~ 1.0 mJy for 90%. Only one QSO, CFHQS J142952+544717, was robustly detected with S_250GHz = 3.46 +/-0.52 mJy. This indicates that one of the most powerful known starbursts at z~6 is associated with this radio loud QSO. On average, the other CFHQS QSOs, which have a mean optical magnitude fainter than previously studied SDSS samples of z~6 QSOs, have a mean 1.2 mm flux density = 0.41 +/-0.14 mJy; such a 2.9-sigma average detection is hardly meaningful. It would correspond to ~ 0.94+/-0.32 10^12 Lo, and an average star formation rate of a few 100's Mo/yr, depending on the IMF and a possible AGN contribution to . This is consistent with previous findings of Wang et al. (2011) on the far-infrared emission of z~6 QSOs and extends them toward optically fainter sources.Comment: 6 pages, 1 figure, A&A in pres

Compact polymer components for an integrated add-drop multiplexer

A phasar and a digital thermo optic switch have been designed and processed in a high index contrast polymer technology. Both devices are small enough to fabricate two integrated add-drop multiplexers on one 4 inch wafe

Tanino condensando das espécies jurema preta (Mimosa hostilis), sabiá (Mimosa caesalpinifolia) e mororó (Bauhinia cheilantha), em três fases do ciclo fenológico.

Resumo: O objetivo do presente trabalho foi caracterizar os taninos condensados das espécies Jurema Preta (Mimosa hostilis), Sabiá (Mimosa caesalpinifolia) e Mororó (Bauhinia cheilantha) nas fases de vegetação(Mimosa hostilis), Sabiá (Mimosa caesalpinifolia) e Mororó (Bauhinia cheilantha) nas fases de vegetação plena, floração plena e frutificação. A concentração em tanino solúvel, tanino ligado ao resíduo e tanino total (TT) foi determinada pelo método butanol-HCL e a adstringência pelo método de difusão radial. Foram observadas diferenças entre as espécies quanto a concentração (P<0,05) e adstringência (P<0,05) dos taninos. A Jurema Preta apresentou os maiores valores (30,98% TT e 22% de adstringência na vegetação plena) e Mororó as menores (10,38% TT e 14% de adstringência na frutificação). A concentração e adstringência dos taninos condensados, assim como a adstringência variaram entre as espécies e, em alguns casos, entre as fases do ciclo fenológico. Os valores observados foram sempre superiores aos considerados benéficos (5%) para a digestão ruminal e aproveitamento geral da dieta. Abstract: This study was conducted aiming at characterizing the condensed tannins present in the legumes species Jurema Preta (Mimosa hostilis), Sabiá (Mimosa caesalpinifolia) and Mororó (Bauhinia cheilantha) at three stages of their phenological cycle. The concentration of soluble tannin, bound tannin and total tannin (TT) was determined using the butanol-HCL method and astringency was determined using the radial diffusion method. Jurema Preta presented the highest values (30.98% TT and 22 % astringency at full growth stage), and Mororó the lowest (10.38% TT and 14 % astringency during fructification). Concentration and astringency of condensed tannins, as well as their monomeric composition varied between species, and in some cases among phenological cycles. The values observed were always above the limits considered beneficial for ruminal digestion (i.e. 5%)

Warmte-koude opslag en duurzaam gebruik van de ondergrond

Warmte koude opslag (WKO) is een energie en kostenbesparende methode voor het verwarmen en koelen van gebouwen. Open WKO systemen pompen het grondwater heen en weer om het gebouw te koelen of te verwarmen. Gesloten WKO systemen gebruiken alleen de warmte van het grondwater om huizen te verwarmen of te koelen. In Nederland is er de laatste jaren een sterke en door de overheid gestimuleerde groei van het aantal WKO systemen. Gesloten WKO systemen zouden een risico kunnen vormen voor de kwaliteit van het grondwater door het groot aantal perforaties van de ondergrond en door het mogelijke lekken van koelvloeistof. Bij open WKO systemen moet voorkomen worden dat verschillende grondwaterlagen gemengd worden waardoor ongewenste geochemische en microbiologische processen optreden. In principe kan een open WKO systeem wel op een vervuilde locatie worden toegepast, maar er is specifiek maatwerk nodig om de verspreiding van de vervuiling te beperken. De bescheiden temperatuursveranderingen die door WKO systemen worden opgewekt in het grondwater vormen slechts een gering risico voor geochemische processen. Deze temperatuursveranderingen zouden in principe wel aanleiding kunnen geven tot een toename van het aantal ziektekiemen in het grondwater. Daarom is het belangrijk dat er voldoende afstand is tussen een drinkwaterwinning en de omringende WKO installaties. Verder onderzoek is nodig om vast te stellen welke invloed WKO installaties hebben op de bacteriën in het grondwater. Het opslaan van heet (90 °C) grondwater heeft een groot aantal milieubezwaren. De Europese kaderrichtlijn water ziet ook de inbreng van warmte in het grondwater als een mogelijke verontreiniging wanneer daar nadelige gevolgen voor mensen of ecosystemen aan verbonden zijn. Het toezicht van de provincies op het groeiende aantal WKO systemen in de praktijk verdient nadere aandacht

Influence of aging and dilution on the crystallization of silicate-1

The correlation between the formation of colloidal aggregates and the crystallization of silicalite-l from a clear solution has been investigated with in situ combined small-angle X-ray scattering and wide-angle X-ray scattering, and in situ ultra- small-angle X-ray scattering using synchrotron radiation. Increasing the aging time at room temperature of the synthesis mixture prior to heating to the reaction temperature reduced the induction period and increased the crystal growth rate without affecting the formation of colloidal aggregates. Dilution of the synthesis mixtures did not influence the nucleation and crystal growth rate, and did not affect the formation of colloidal aggregate

A Search for Dense Molecular Gas in High Redshift Infrared-Luminous Galaxies

We present a search for HCN emission from four high redshift far infrared (IR) luminous galaxies. Current data and models suggest that these high $z$ IR luminous galaxies represent a major starburst phase in the formation of spheroidal galaxies, although many of the sources also host luminous active galactic nuclei (AGN), such that a contribution to the dust heating by the AGN cannot be precluded. HCN emission is a star formation indicator, tracing dense molecular hydrogen gas within star-forming molecular clouds (n(H$_2$) $\sim 10^5$ cm$^{-3}$). HCN luminosity is linearly correlated with IR luminosity for low redshift galaxies, unlike CO emission which can also trace gas at much lower density. We report a marginal detection of HCN (1-0) emission from the $z=2.5832$ QSO J1409+5628, with a velocity integrated line luminosity of $L_{\rm HCN}'=6.7\pm2.2 \times10^{9}$ K km s$^{-1}$ pc$^2$, while we obtain 3$\sigma$ upper limits to the HCN luminosity of the $z=3.200$ QSO J0751+2716 of $L_{\rm HCN}'=1.0\times10^{9}$ K km s$^{-1}$ pc$^2$, $L_{\rm HCN}'=1.6\times10^{9}$ K km s$^{-1}$ pc$^2$ for the $z= 2.565$ starburst galaxy J1401+0252, and $L_{\rm HCN}'=1.0\times10^{10}$ K km s$^{-1}$ pc$^2$ for the $z = 6.42$ QSO J1148+5251. We compare the HCN data on these sources, plus three other high-$z$ IR luminous galaxies, to observations of lower redshift star-forming galaxies. The values of the HCN/far-IR luminosity ratios (or limits) for all the high $z$ sources are within the scatter of the relationship between HCN and far-IR emission for low $z$ star-forming galaxies (truncated).Comment: aastex format, 4 figures. to appear in the Astrophysical Journal; Revised lens magnification estimate for 1401+025

Molecular gas in QSO host galaxies at z>5

We present observations with the IRAM Plateau de Bure Interferometer of three QSOs at z>5 aimed at detecting molecular gas in their host galaxies as traced by CO transitions. CO (5-4) is detected in SDSSJ033829.31+002156.3 at z=5.0267, placing it amongst the most distant sources detected in CO. The CO emission is unresolved with a beam size of ~1", implying that the molecular gas is contained within a compact region, less than ~3kpc in radius. We infer an upper limit on the dynamical mass of the CO emitting region of ~3x10^10 Msun/sin(i)^2. The comparison with the Black Hole mass inferred from near-IR data suggests that the BH-to-bulge mass ratio in this galaxy is significantly higher than in local galaxies. From the CO luminosity we infer a mass reservoir of molecular gas as high as M(H2)=2.4x10^10 Msun, implying that the molecular gas accounts for a significant fraction of the dynamical mass. When compared to the star formation rate derived from the far-IR luminosity, we infer a very short gas exhaustion timescale (~10^7 yrs), comparable to the dynamical timescale. CO is not detected in the other two QSOs (SDSSJ083643.85+005453.3 and SDSSJ163033.90+401209.6) and upper limits are given for their molecular gas content. When combined with CO observations of other type 1 AGNs, spanning a wide redshift range (0<z<6.4), we find that the host galaxy CO luminosity (hence molecular gas content) and the AGN optical luminosity (hence BH accretion rate) are correlated, but the relation is not linear: L(CO) ~ [lambda*L_lambda(4400A)]^0.72. Moreover, at high redshifts (and especially at z>5) the CO luminosity appears to saturate. We discuss the implications of these findings in terms of black hole-galaxy co-evolution.Comment: Accepted for publication in A&A Letters, 6 pages, 3 figure