2,750 research outputs found
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
Stability, reliability and cross-mode correlations of tests in a recommended 8-minute performance assessment battery
A need exists for an automated performance test system to study drugs, agents, treatments, and stresses of interest to the aviation, space, and environmental medical community. The purpose of this present study is to evaluate tests for inclusion in the NASA-sponsored Automated Performance Test System (APTS). Twenty-one subjects were tested over 10 replications with tests previously identified as good candidates for repeated-measure research. The tests were concurrently administered in paper-and-pencil and microcomputer modes. Performance scores for the two modes were compared. Data from trials 1 to 10 were examined for indications of test stability and reliability. Nine of the ten APT system tests achieved stability. Reliabilities were generally high. Cross-correlation of microbased tests with traditional paper-and-pencil versions revealed similarity of content within tests in the different modes, and implied at least three cognition and two motor factors. This protable, inexpensive, rugged, computerized battery of tests is recommended for use in repeated-measures studies of environmental and drug effects on performance. Identification of other tests compatible with microcomputer testing and potentially capable of tapping previously unidentified factors is recommended. Documentation of APTS sensitivity to environmental agents is available for more than a dozen facilities and is reported briefly. Continuation of such validation remains critical in establishing the efficacy of APTS tests
Composition of fungal communities in soil and endophytic in raspberry production systems.
Fungi play important roles as decomposers, plant symbionts and pathogens in soil. While endophytes are microorganisms that dwell within plant tissues and have a symbiotic association with the host. The structures of fungal communities in the soil and in endophytic association are dependent up complex interactions with the environment and the host. These two communities have a great influence on plant health and development. Using culture-independent fungal community profiling, we investigated the effects of fertilizer (composted dairy solids + mustard seed meal) on fungal communities in soil and endophytic in a raspberry production system. During the study we evaluated the impact of primer selection ITS1 vs ITS2. We characterized the communities for both spring and fall time periods. The results show that the soil communities are dominated by Ascomycota, and Basidiomycota in soil, while the endophytes were primarily Ascomycota. The relative abundances of certain taxa, such as Capnodiales, were more predominant in composted soil (8%) than the control (4%). There were no significant differences identified in the endophytic communities between the two treatments. Further research should elucidate the specific roles of these fungal taxa in raspberry soils and endophyte, and on the heath of the plant. To advance the ecological management of crop soils, understanding is needed of how beneficial microbial relationships can be fostered in these production systems
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
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 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 .Comment: 4 pages, 3 figure
Topological Phases in Graphitic Cones
The electronic structure of graphitic cones exhibits distinctive topological
features associated with the apical disclinations. Aharonov-Bohm
magnetoconductance oscillations (period Phi_0) are completely absent in rings
fabricated from cones with a single pentagonal disclination. Close to the apex,
the local density of states changes qualitatively, either developing a cusp
which drops to zero at the Fermi energy, or forming a region of nonzero density
across the Fermi energy, a local metalization of graphene.Comment: 4 pages, RevTeX 4, 3 PostScript figure
Un nouveau paradigme Ă©cologique pour une sociologie post-abondance
La sociologie s’est développée dans le contexte d’une vision occidentale dominante du monde (DWW) extrêmement anthropocentrique, selon laquelle les humains seraient séparés du reste de la nature et considéreraient l’abondance des ressources, la croissance et le progrès comme allant de soi. La sociologie a adopté cette vision du monde optimiste et y a ajouté des caractéristiques disciplinaires spécifiques – notamment l’énoncé d’Émile Durkheim selon lequel les faits sociaux ne devaient pas être expliqués par des facteurs psychologiques, biologiques ou environnementaux – ce qui l’a d’autant plus encouragée à ignorer l’environnement biophysique. Au cours de la moitié du xxe siècle, la sociologie a reposé sur un paradigme disciplinaire qui voyait les sociétés modernes industrialisées comme « exemptées » des contraintes écologiques. En raison du paradigme de l’exemptionnalisme humain (HEP), l’appréhension par la sociologie de la signification sociale des preuves croissantes de la pollution, de la pénurie des ressources et des autres problèmes écologiques a été lente. Cependant, la reconnaissance croissante de ces problèmes a stimulé le champ de la sociologie de l’environnement et une reconnaissance graduelle de la dépendance des sociétés modernes à l’écosystème, donnant un essor à un nouveau paradigme écologique (NEP). Les hypothèses fondant la DWW, le HEP et le NEP sont d’abord présentées, les relations entre la distinction HEP-NEP et les clivages sociologiques traditionnels comme ordre versus conflit sont ensuite discutées de manière à démontrer l’utilité du NEP dans une ère de croissance des contraintes écologiques.Sociology developed in the context of a highly anthropocentric Dominant Western Worldview (DWW) that saw humans as separate from the rest of nature and took resource abundance, growth and progress for granted. Sociology adopted this optimistic worldview, and added unique disciplinary characteristics—especially Durkheim’s dictum that social facts should not be explained by psychological, biological or environmental factors--that further encouraged ignoring the bio-physical environment. By mid-20th century, sociology was premised on a disciplinary paradigm that viewed modern industrial societies as “exempt” from ecological constraints. This Human Exemptionalism Paradigm (HEP) made sociology slow to see the societal significance of mounting evidence of pollution, resource scarcities and other ecological problems. However, growing recognition of these problems stimulated a field of environmental sociology and a gradual recognition of the ecosystem-dependence of modern societies, giving rise to a New Ecological Paradigm (NEP). The basic assumptions of the DWW, HEP and NEP are presented, and then the relationship between the HEP-NEP distinction and traditional sociological cleavages such as order vs. conflict are discussed in order to demonstrate the utility of the NEP in an era of growing ecological constraints
Localization Properties of Electronic States in Polaron Model of poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers
We numerically investigate localization properties of electronic states in a
static model of poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers with
realistic parameters obtained by quantum-chemical calculation. The randomness
in the on-site energies caused by the electron-phonon coupling are completely
correlated to the off-diagonal parts. In the single electron model, the effect
of the hydrogen-bond stretchings, the twist angles between the base pairs and
the finite system size effects on the energy dependence of the localization
length and on the Lyapunov exponent are given. The localization length is
reduced by the influence of the fluctuations in the hydrogen bond stretchings.
It is also shown that the helical twist angle affects the localization length
in the poly(dG)-poly(dC) DNA polymer more strongly than in the
poly(dA)-poly(dT) one. Furthermore, we show resonance structures in the energy
dependence of the localization length when the system size is relatively small.Comment: 6 pages, 6 figure
- …