Constraints On the Size Evolution of Brightest Cluster Galaxies

We measure the luminosity profiles of 16 brightest cluster galaxies (BCGs) at $0.4 < z < 0.8$ using high resolution F160W NICMOS and F814W WFPC2 HST imaging. The heterogeneous sample is drawn from a variety of surveys: seven from clusters in the Einstein Medium Sensitivity Survey, five from the Las Campanas Distant Cluster Survey and its northern hemisphere precursor, and the remaining four from traditional optical surveys. We find that the surface brightness profiles of all but three of these BCGs are well described by a standard de Vaucouleurs ($r^{1/4}$) profile out to at least $\sim2r_{e}$ and that the biweight-estimated NICMOS effective radius of our high redshift BCGs ($r_{e} = 8.3\pm 1.4$ kpc for $H_{0} = 80$ km s$^{-1}$ Mpc$^{-1}$, $\Omega_{m} = 0.2, \Omega_\Lambda = 0.0$) is $\sim 2$ times smaller than that measured for a local BCG sample. If high redshift BCGs are in dynamical equilibrium and satisfy the same scaling relations as low redshift ones, this change in size would correspond to a mass growth of a factor of 2 since $z \sim 0.5$. However, the biweight-estimated WFPC2 effective radius of our sample is 18 $\pm$ 5.1 kpc, which is fully consistent with the local sample. While we can rule out mass accretion rates higher than a factor of 2 in our sample, the discrepancy between our NICMOS and WFPC2 results, which after various tests we describe appears to be physical, does not yet allow us to place strong constraints on accretion rates below that level.Comment: ApJ accepted (566, 1, February 2002), 12 pages, uses emulateapj5.st

Household stored water quality in an intermittent water supply network in Panama

Safe water storage is critical to preserve water quality, especially when intermittent piped drinking water supply creates a need for household storage. This study characterized household storage practices and stored water quality in 94 households (N = 94) among four peri-urban neighborhoods in Arraiján, Panama with varying degrees of supply intermittency. We found that 18 (19.1%) households stored drinking water in unsafe containers. Forty-four (47%) samples of household stored drinking water had residual chlorine levels 10 most probable number (MPN)/100 mL total coliform bacteria. Eight (44%) samples were positive for Escherichia coli, whereas only one (1.3%) sample from the safe containers was positive. Twenty-nine (30.9%) samples had >500 MPN/mL heterotrophic plate count bacteria. These findings suggest that longer supply interruptions were associated with longer storage times and lower chlorine residual, which were associated with higher concentrations of indicator bacteria. This is one of the first studies in the Central-American region to show an association between the lack of turnover (replacement with fresh water) and greater contamination during household water storage. Thus, when drinking water supply is not completely continuous and household storage is required, decreasing the time between supply periods can facilitate safer water storage. Public awareness and education are also recommended to increase hygiene practices during water collection and storage.Safe water storage is critical to preserve water quality, especially when intermittent piped drinking water supply creates a need for household storage. This study characterized household storage practices and stored water quality in 94 households (N = 94) among four peri-urban neighborhoods in Arraiján, Panama with varying degrees of supply intermittency. We found that 18 (19.1%) households stored drinking water in unsafe containers. Forty-four (47%) samples of household stored drinking water had residual chlorine levels 10 most probable number (MPN)/100 mL total coliform bacteria. Eight (44%) samples were positive for Escherichia coli, whereas only one (1.3%) sample from the safe containers was positive. Twenty-nine (30.9%) samples had >500 MPN/mL heterotrophic plate count bacteria. These findings suggest that longer supply interruptions were associated with longer storage times and lower chlorine residual, which were associated with higher concentrations of indicator bacteria. This is one of the first studies in the Central-American region to show an association between the lack of turnover (replacement with fresh water) and greater contamination during household water storage. Thus, when drinking water supply is not completely continuous and household storage is required, decreasing the time between supply periods can facilitate safer water storage. Public awareness and education are also recommended to increase hygiene practices during water collection and storage

Patterns of Individual Shopping Behavior

Much of economic theory is built on observations of aggregate, rather than individual, behavior. Here, we present novel findings on human shopping patterns at the resolution of a single purchase. Our results suggest that much of our seemingly elective activity is actually driven by simple routines. While the interleaving of shopping events creates randomness at the small scale, on the whole consumer behavior is largely predictable. We also examine income-dependent differences in how people shop, and find that wealthy individuals are more likely to bundle shopping trips. These results validate previous work on mobility from cell phone data, while describing the unpredictability of behavior at higher resolution.Comment: 4 pages, 5 figure

Cluster Galaxy Evolution from a New Sample of Galaxy Clusters at 0.3 < z < 0.9

(Abridged) We analyze photometry and spectroscopy of a sample of 63 clusters at 0.3<z<0.9 drawn from the Las Campanas Distant Cluster Survey to empirically constrain models of cluster galaxy evolution. Specifically, by combining data on our clusters with those from the literature we parametrize the redshift dependence of 1) M*_I in the observed frame; 2) the V-I color of the E/S0 red sequence in the observed frames; and 3) the I-K' color of the E/S0 red sequence in the observed frame. Using the peak surface brightness of the cluster detection, S, as a proxy for cluster mass, we find no correlation between S and M* or the location of the red envelope in V-I. We suggest that these observations can be explained with a model in which luminous early type galaxies (or more precisely, the progenitors of current day luminous early type galaxies) form the bulk of their stellar populations at high redshift (>~ 5) and in which many of these galaxies, if not all, accrete mass either in the form of evolved stellar populations or gas that causes only a short term episode of star formation at lower redshifts (1.5 < z < 2). Our data are too crude to reach conclusions regarding the evolutionary state of any particular cluster or to investigate whether the morphological evolution of galaxies matches the simple scenario we discuss, but the statistical nature of this study suggests that the observed evolutionary trends are universal in massive clusters.Comment: 35 pages, accepted for publication in Ap

Detection of a Corrugated Velocity Pattern in the Spiral Galaxy NGC 5427

Here we report the detection, in Halpha emission, of a radial corrugation in the velocity field of the spiral galaxy NGC 5427. The central velocity of the Halpha line displays coherent, wavy-like variations in the vicinity of the spiral arms. The spectra along three different arm segments show that the maximum amplitude of the sinusoidal line variations are displaced some 500 pc from the central part of the spiral arms. The peak blueshifted velocities appear some 500 pc upstream the arm, whereas the peak redshifted velocities are located some 500 pc downstream the arm. This kinematical behavior is similar to the one expected in a galactic bore generated by the interaction of a spiral density wave with a thick gaseous disk, as recently modeled by Martos & Cox (1998).Comment: Accepted for publication in Ap

Life in Hot Carbon Monoxide: The Complete Genome Sequence of Carboxydothermus hydrogenoformans Z-2901

We report here the sequencing and analysis of the genome of the thermophilic bacterium Carboxydothermus hydrogenoformans Z-2901. This species is a model for studies of hydrogenogens, which are diverse bacteria and archaea that grow anaerobically utilizing carbon monoxide (CO) as their sole carbon source and water as an electron acceptor, producing carbon dioxide and hydrogen as waste products. Organisms that make use of CO do so through carbon monoxide dehydrogenase complexes. Remarkably, analysis of the genome of C. hydrogenoformans reveals the presence of at least five highly differentiated anaerobic carbon monoxide dehydrogenase complexes, which may in part explain how this species is able to grow so much more rapidly on CO than many other species. Analysis of the genome also has provided many general insights into the metabolism of this organism which should make it easier to use it as a source of biologically produced hydrogen gas. One surprising finding is the presence of many genes previously found only in sporulating species in the Firmicutes Phylum. Although this species is also a Firmicutes, it was not known to sporulate previously. Here we show that it does sporulate and because it is missing many of the genes involved in sporulation in other species, this organism may serve as a “minimal” model for sporulation studies. In addition, using phylogenetic profile analysis, we have identified many uncharacterized gene families found in all known sporulating Firmicutes, but not in any non-sporulating bacteria, including a sigma factor not known to be involved in sporulation previously

Preliminary observations on carcass traits and meat yield of five types of Brahman-influenced grass-fed bulls

Benefiting from interventions of the savanna ecosystem, breeders in Los Llanos of Apure State (Venezuela) are exploring the opportunity to improve cattle genetics by implementing crossbreeding programs. &nbsp;Fifty yearling bulls of five types of Brahman influence [ST-Brahman (n = 10), F1 Angus x Brahman (F1-Angus; n = 10), F1 Chianina x Brahman (F1-Chianina; n = 10), F1 Romosinuano x Brahman (F1-Romosinuano; n = 10), and F1 Simmental x Brahman (F1-Simmental; n = 10)] were selected to be compared in carcass performance (linear measurements, quality and quantity indicators, Venezuelan and U.S. grades, and cutability) at a desirable conformation endpoint with a suitable market weight of 480 kg.&nbsp; Shorter ST-Brahman carcasses exhibited the most abundant finish, significantly different from the longer F1-Simmental and F1-Romosinuano counterparts.&nbsp; All carcasses fell into the A youngest maturity and were eligible for the USDA "Bullock “class designation; 62% reached the top Venezuelan quality grade, 96% graded US Standard and 64% reached the US yield grade 1, indicating superior cutability. Significant differences in yield of individual cuts (ribeye + strip loin, and cuts from the round) were detected between F1-Romosinuano and St-Brahman, F1-Angus and F1-Chianina counterparts.&nbsp; F1-Chianina bulls had slight but significant advantages in yield of high-valued boneless cuts as compared to those of F1-Romosinuano and F1-Simmental counterparts. Conversely, F1-Romosinuano outperformed F1-Chianina in 1.73 percentage points of medium-valued boneless cuts (P &lt; 0.05). &nbsp;Under the sample selection criteria and harvest endpoint, slight changes in carcass performance can be expected from crossbreeding.Con intervenciones del ecosistema sabana y aplicando un manejo adecuado de los pastos, ganaderos de Los Llanos del Estado Apure (Venezuela) estan explorando mejorar la genética del ganado con programas de cruzamiento.&nbsp; Cincuenta machos enteros añosos de cinco tipos raciales con influencia Brahman [Brahman puro (n = 10), F1 Angus x Brahman (F1-Angus; n = 10), F1 Chianina x Brahman (F1-Chianina; n = 10), F1 Romosinuano x Brahman (F1-Romosinuano; n = 10) y F1 Simmental x Brahman (F1-Simmental; n = 10)] se compararon en desempeño de la canal (mediciones lineales, indicadores de calidad y cantidad, categorías de clasificación y rendimiento carnicero) a un punto final de conformación deseable con un peso corporal aproximado de 480 kg.&nbsp; Canales más cortas de Brahman puros exhibieron acabado más abundante, diferente (P&lt;0.05) de las contrapartes más largas F1-Simmental y F1-Romosinuano.&nbsp; Todas las canales cayeron en la madurez más joven (A) y fueron elegibles para la designación de clase "Bullock" del USDA; el 62% alcanzó el grado de calidad superior venezolano (categoría A), el 96% calificó en el grado de calidad Standard y el 64% alcanzó el grado máximo de rendimiento carnicero (grado 1 USDA).&nbsp; Los toretes F1-Chianina tuvieron ventajas leves pero significativas en rendimiento en cortes deshuesados de alto valor, en comparación con los de F1-Romosinuano y F1-Simmental.&nbsp; Por el contrario, F1-Romosinuano superó a F1-Chianina en 1,73 puntos porcentuales de cortes deshuesados de valor medio (P &lt;0.05).&nbsp; Bajo los criterios de selección de la muestra y el punto final de la cosecha, no se pueden esperar grandes cambios en el rendimiento carnicero a partir del cruzamiento.Com o uso de tecnologias em um ecossistema de savana e aplicando um manejo adequado das pastagens, os criadores de Los Llanos do Estado de Apure (Venezuela) estão tentando melhorar a genética do gado através da utilização de programas de cruzamento. &nbsp;Cinquenta bovinos machos não castrados, com peso de abate de ~480 kg, de cinco cruzamentos com Brahman [Brahman puro (n = 10), F1 Angus x Brahman (F1-Angus; n = 10), F1 Chianina x Brahman (F1-Chianina; n = 10), F1 Romosinuano x Brahman (F1-Romosinuano; n = 10) e F1 Simental x Brahman (F1-Simental; n = 10)], foram comparados quanto às características (medidas lineares, indicadores de qualidade e quantidade e rendimento de desossa) y tipificacao de carcaça.&nbsp;&nbsp;&nbsp; Carcaças de Brahman puros apresentaram maior cobertura de gordura do que carcaças de animais F1-Simmental e F1-Romosinuano (P&lt;0.05).&nbsp; Todas as carcaças foram com maturidade “A” (jovem / Bullock), sendo que 96% se qualificaram no grau de qualidade USDA “Standard” e 64% alcançaram o grau máximo de rendimento de desossa (grau 1). &nbsp;Pelo padrão venezuelano, 62% das carcaças alcançaram o grau de qualidade superior (categoria A). &nbsp;Diferenças significativas foram detectadas no rendimento de cortes individuais (filé de costela e contrafilé e cortes do coxão) entre carcaças de F1-Romosinuano e F1-Simental e F1-Angus e F1-Chianina. Carcaças de F1-Chianina apresentaram maiores rendimentos em cortes desossados de alto valor em comparação com F1-Romosinuano e F1-Simmental. &nbsp;Carcaças de F1-Romosinuano tiveram 1,73 pontos percentuais a mais de rendimento em cortes desossados de valor intermediário, que carcaças de F1-Chianina (P &lt;0,05). Segundo os critérios de seleção da amostra e o ponto final de abate, não se podem esperar grandes mudanças na qualidade e rendimento das carcaças de diferentes cruzamentos. &nbsp

IGR J19552+0044: A new asynchronous short period polar: "Filling the gap between intermediate and ordinary polars"

Based on XMM--Newton X-ray observations IGR J19552+0044 appears to be either a pre-polar or an asynchronous polar. We conducted follow-up optical observations to identify the sources and periods of variability precisely and to classify this X-ray source correctly. Extensive multicolor photometric and medium- to high-resolution spectroscopy observations were performed and period search codes were applied to sort out the complex variability of the object. We found firm evidence of discording spectroscopic (81.29+/-0.01m) and photometric (83.599+/-0.002m) periods that we ascribe to the white dwarf (WD)\ spin period and binary orbital period, respectively. This confirms that IGR J19552+0044 is an asynchronous polar. Wavelength-dependent variability and its continuously changing shape point at a cyclotron emission from a magnetic WD with a relatively low magnetic field below 20 MG. The difference between the WD spin period and the binary orbital period proves that IGR J19552+0044 is a polar with the largest known degree of asynchronism (0.97 or 3%).Comment: 9 pages, 10 figures, A&A accepte

Evolution of BCGs structural parameters in the last ∼\sim6 Gyr: feedback processes versus merger events

We present results on the evolution in the last 6 Gyr of the structural parameters of two samples of brightest cluster galaxies (BCGs). The nearby sample of BCGs consist on 69 galaxies from the WINGS survey spanning a redshift range of 0.04$<$z$<$0.07. The intermediate redshift (0.3$<$z$<$0.6) sample is formed by 20 BCGs extracted from the Hubble Space Telescope archive. Both samples have similar spatial resolution and their host clusters have similar X-ray luminosities. We report an increase in the size of the BCGs from intermediate to local redshift. However, we do not detect any variation in the S\'ersic shape parameter in both samples. These results are proved to be robust since the observed tendencies are model independent. We also obtain significant correlations between some of the BCGs parameters and the main properties of the host clusters. More luminous, larger and centrally located BCGs are located in more massive and dominant galaxy clusters. These facts indicate that the host galaxy cluster has played an important role in the formation of their BCGs. We discuss the possible mechanisms that can explain the observed evolution of the structural parameters of the BCGs. We conclude that the main mechanisms that can explain the increase in size and the non-evolution in the S\'ersic shape parameter of the BCGs in the last 6 Gyr are feedback processes. This result disagrees with semi-analytical simulation results supporting that merging processes are the main responsible for the evolution of the BCGs until the present epoch.Comment: Accepted for publication in ApJ; 17 pages, 7 figures; 10 table

Murine model for Fusarium oxysporum invasive fusariosis reveals organ-specific structures for dissemination and long-term persistence

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