Axial Ratio of Edge-On Spiral Galaxies as a Test For Extended Bright Radio Halos

We use surface brightness contour maps of nearby edge-on spiral galaxies to determine whether extended bright radio halos are common. In particular, we test a recent model of the spatial structure of the diffuse radio continuum by Subrahmanyan and Cowsik which posits that a substantial fraction of the observed high-latitude surface brightness originates from an extended Galactic halo of uniform emissivity. Measurements of the axial ratio of emission contours within a sample of normal spiral galaxies at 1500 MHz and below show no evidence for such a bright, extended radio halo. Either the Galaxy is atypical compared to nearby quiescent spirals or the bulk of the observed high-latitude emission does not originate from this type of extended halo.Comment: 6 Pages, 4 Figures, 1 Table; To Appear In ApJ Letter

The Corralitos Observatory program for the detection of lunar transient phenomena

This is a final report on the establishment, observing procedures, and observational results of a survey program for the detection of lunar transient phenomena (LTP's) by electro-optical image conversion means. For survey, a unique detection system with an image orthicon was used as the primary element in conjunction with a 24-in. f/20 Cassegrainian telescope. Observations in three spectral ranges, with 6,466 man-hours of observing, were actually performed during the period from October 27, 1965, to April 26, 1972. Within this entire period, no color or feature change within the detection capabilities of the instrumentation was observed, either independently or in follow up of amateur LTP reports, with the exception of one general bluing and several localized bluings (probably ascribable to the effects of the terrestrial atmosphere) that were observed solely by the Corralitos system. A table is presented indicating amateur and professional reports of LTP's and the results of efforts to confirm these reports through the Corralitos system

Social identity and environmental concern: the importance of contextual effects

This study draws on social identity theory to explain differences in individual support for environmental protection, a conative component of environmental concern. It argues that an individual’s identification with higher social units—community, nation, and world—strengthens its in-group solidarity and empathy and, in consequence, its readiness to protect the environment benefitting the in-group’s welfare. The study hypothesizes that country-level manifestations of social identity (1) lift individuals’ support for environmental protection above the level that their own social identity suggests (elevator effect), and (2) reinforce the effect of individuals’ social identity on their support for environmental protection (amplifier effect). Using a sample of over 30,000 individuals located in 38 countries around the world, the study finds strong evidence for the two contextual effects. The findings indicate that social identity plays an important role not just as an individual attribute but also as a central component of culture in fostering environmental concern

Sugar cane bagasse affects bacterial community dynamics in the sheep rumen.

Ruminants are herbivores and have evolved a symbiotic host-microbe relationship with a complex microbial community inhabiting the rumen allowing the use of lignocellulosic biomass as their main energy source. Considering that diet is one of the main drivers shaping the structure of the rumen microbiome, we investigated the impact of sugarcane bagasse in the rumen bacterial community dynamic using 16S rRNA (V3 and V6 regions) amplicon sequencing. We assessed three rumencannulated adult male sheep (Ovis aries) fed on a diet consisted of 30% concentrate and 70% roughage (control treatment) and three sheep fed on the same diet, but with 14% of the roughage portion replaced by sugarcane bagasse. Fluid and fiber were separately sampled 3 hours and 15, 30, 45, and 60 days after starting the experiment. Total genomic DNA was extracted from 60 independent samples (2 treatments X 3 replicates X 5 time points X 2 types of samples, i.e. fluid or fiber) for downstream analysis. The DNA was used as a template for amplification of V3 and V6 regions of the bacterial 16S rRNA gene and then sequenced using the PGMTM (Ion Torrent). Overall, the two dominant phyla were Bacteroidetes (42%) and Firmicutes (37%). The most abundant bacterial genus was Prevotella (20%), followed by Clostridium (9%), Ruminococcus (8%) and Butyrivibrio (2%). The principal coordinate analysis (PcoA) showed that the bacterial community was significantly different in both treatments at 60 days. Bacteroidales, Actinomycetales and Clostridiales were the top dynamic bacterial orders that significantly increased in relative abundance in the treatment with sugar cane bagasse after 60 days. Canonical correspondence analysis (CCA) revealed that the Clostridiales and Bacteroidales are positively correlated with propionate, butyrate, ammonia, and pH. These results indicate that a small replacement in the diet roughage portion influences de dynamic of specific bacterial taxa. This strategy can be used to reshape the bacterial community in the sheep rumen aiming to enrich the targeted bacterial taxa. Support FAPESP 2012/03848-8, 2012/24588-4 and 2014/00448-4.13th BAGECO1

Growth and Structure of Stochastic Sequences

We introduce a class of stochastic integer sequences. In these sequences, every element is a sum of two previous elements, at least one of which is chosen randomly. The interplay between randomness and memory underlying these sequences leads to a wide variety of behaviors ranging from stretched exponential to log-normal to algebraic growth. Interestingly, the set of all possible sequence values has an intricate structure.Comment: 4 pages, 4 figure

Location of Mach Discs and Diamonds Supersonic Air Jets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77542/1/AIAA-3788-127.pd

Scaling Properties of 1D Anderson Model with Correlated Diagonal Disorder

Statistical and scaling properties of the Lyapunov exponent for a tight-binding model with the diagonal disorder described by a dichotomic process are considered near the band edge. The effect of correlations on scaling properties is discussed. It is shown that correlations lead to an additional parameter governing the validity of single parameter scaling.Comment: 5 pages, 3 figures, RevTe

Genome Evolution in the Obligate but Environmentally Active Luminous Symbionts of Flashlight Fish

The luminous bacterial symbionts of anomalopid flashlight fish are thought to be obligately dependent on their hosts for growth and share several aspects of genome evolution with unrelated obligate symbionts, including genome reduction. However, in contrast to most obligate bacteria, anomalopid symbionts have an active environmental phase that may be important for symbiont transmission. Here we investigated patterns of evolution between anomalopid symbionts compared with patterns in free-living relatives and unrelated obligate symbionts to determine if trends common to obligate symbionts are also found in anomalopid symbionts. Two symbionts, ?Candidatus Photodesmus katoptron? and ?Candidatus Photodesmus blepharus,? have genomes that are highly similar in gene content and order, suggesting genome stasis similar to ancient obligate symbionts present in insect lineages. This genome stasis exists in spite of the symbiont?s inferred ability to recombine, which is frequently lacking in obligate symbionts with stable genomes. Additionally, we used genome comparisons and tests of selection to infer which genes may be particularly important for the symbiont?s ecology compared with relatives. In keeping with obligate dependence, substitution patterns suggest that most symbiont genes are experiencing relaxed purifying selection compared with relatives. However, genes involved in motility and carbon storage, which are likely to be used outside the host, appear to be under increased purifying selection. Two chemoreceptor chemotaxis genes are retained by both species and show high conservation with amino acid sensing genes, suggesting that the bacteria may actively seek out hosts using chemotaxis toward amino acids, which the symbionts are not able to synthesize

Extended States in a One-dimensional Generalized Dimer Model

The transmission coefficient for a one dimensional system is given in terms of Chebyshev polynomials using the tight-binding model. This result is applied to a system composed of two impurities located between $N$ sites of a host lattice. It is found that the system has extended states for several values of the energy. Analytical expressions are given for the impurity site energy in terms of the electron's energy. The number of resonant states grows like the number of host sites between the impurities. This property makes the system interesting since it is a simple task to design a configuration with resonant energy very close to the Fermi level $E_F$.Comment: 4 pages, 3 figure

Quantitative analysis of regulatory flexibility under changing environmental conditions

The circadian clock controls 24-h rhythms in many biological processes, allowing appropriate timing of biological rhythms relative to dawn and dusk. Known clock circuits include multiple, interlocked feedback loops. Theory suggested that multiple loops contribute the flexibility for molecular rhythms to track multiple phases of the external cycle. Clear dawn- and dusk-tracking rhythms illustrate the flexibility of timing in Ipomoea nil. Molecular clock components in Arabidopsis thaliana showed complex, photoperiod-dependent regulation, which was analysed by comparison with three contrasting models. A simple, quantitative measure, Dusk Sensitivity, was introduced to compare the behaviour of clock models with varying loop complexity. Evening-expressed clock genes showed photoperiod-dependent dusk sensitivity, as predicted by the three-loop model, whereas the one- and two-loop models tracked dawn and dusk, respectively. Output genes for starch degradation achieved dusk-tracking expression through light regulation, rather than a dusk-tracking rhythm. Model analysis predicted which biochemical processes could be manipulated to extend dusk tracking. Our results reveal how an operating principle of biological regulators applies specifically to the plant circadian clock