197 research outputs found
Interrelationships among attachment style, personality traits, interpersonal competency, and Facebook use
Online social media has become a popular way to communicate and develop interpersonal relationships. Facebook use in particular has become an important topic for researchers and clinicians, as young adults are increasingly integrating this use into their daily lives and social behavior. As empirical work on the personality traits and interpersonal competency associated with use and the potential consequences of use on social behavior is still emerging, the present study sought to investigate the interrelationships among constructs relevant to the developmental tasks associated with emerging adulthood, including adult attachment style, Five Factor Model personality traits, interpersonal competency, and Facebook use. Using data collected from 617 emerging adults in college, we utilized structural equation modeling to develop a model explaining the interrelationships among the constructs under study in order to further the research in this area. Results yielded a well-fitting model that explained the interrelationships among these latent constructs in the data, which suggested that insecure attachment had direct and positive effects on neuroticism, direct and negative effects on extraversion, direct and negative effects on interpersonal competency, and indirect effects on Facebook use. In addition, only extraversion and not neuroticism was related to interpersonal competency and Facebook use, when first accounting for attachment style. Interestingly, interpersonal competency did not seem to play a prominent mediating role between these personality traits and Facebook use. These results highlight the role of attachment style, and its importance in both developing personality traits, interpersonal skills, and online social behavior, which aligns well with the attachment theory framework. Lastly, we discussed future directions for research, as well as theoretical and practice implications for psychologists
Examination of Triacylglycerol Biosynthetic Pathways via De Novo Transcriptomic and Proteomic Analyses in an Unsequenced Microalga
Biofuels derived from algal lipids represent an opportunity to dramatically impact the global energy demand for transportation fuels. Systems biology analyses of oleaginous algae could greatly accelerate the commercialization of algal-derived biofuels by elucidating the key components involved in lipid productivity and leading to the initiation of hypothesis-driven strain-improvement strategies. However, higher-level systems biology analyses, such as transcriptomics and proteomics, are highly dependent upon available genomic sequence data, and the lack of these data has hindered the pursuit of such analyses for many oleaginous microalgae. In order to examine the triacylglycerol biosynthetic pathway in the unsequenced oleaginous microalga, Chlorella vulgaris, we have established a strategy with which to bypass the necessity for genomic sequence information by using the transcriptome as a guide. Our results indicate an upregulation of both fatty acid and triacylglycerol biosynthetic machinery under oil-accumulating conditions, and demonstrate the utility of a de novo assembled transcriptome as a search model for proteomic analysis of an unsequenced microalga
Continuous gas processing without bubbles using thin liquid film bioreactors containing biocomposite biocatalysts
Continuous microbial gas processing without bubbles is possible with thin liquid film, plug flow bioreactors. We have demonstrated that power input can be minimized by using a falling liquid film operating under laminar wavy flow conditions (Re \u3c200) in contact with highly concentrated living, non-growing microbes stabilized in a porous biocomposite biocatalyst. This composite materials approach to continuous gas processing can dramatically increase mass transfer rates \u3e100 fold compared to bubble aeration, decrease process volume, significantly decrease gas-liquid mass transfer energy input, decrease water use, and increase secreted product concentration. We have shown that this approach can also increase microbial specific activity for some organisms compared to microbes suspended in liquid media. Paper-based biocomposite biocatalysts provide a rough hydrophilic surface resulting in uniform ~300 ÎĽm thick falling liquid films. Paper roughness enhances gas-liquid-microbe mass transfer. This mass transfer enhancement has been simulated using a finite element (FEM) CFD model. The paper structure also functions as a separation device - the secreted products are released into the falling liquid film and continuously removed from the reactor. We are investigating biocomposite biocatalyst design and stabilization using a 0.05 m2 prototype cylindrical paper falling film bioreactor (FFBR). This approach can be used for continuous gas processing with either non-photosynthetic or photosynthetic microorganisms. Current experimental model systems we are investigating include Clostridium ljungdahlii OTA1 for absorbing CO from syn-gas, Methylomycrobium alkaliphilum 20Z for absorbing CH4 in air, and Chlamydomonas renhardtii for CO2 emissions. Critical to biocomposite biocatalyst design are generation of nanoporous coating microstructure, microbe adhesion to paper during film formation (which may include engineering the surface of the microbes), surviving osmotic shock in coating formulations, as well as desiccation tolerance to drying and prolonged dry storage. Spatially correlated Raman microspectroscopy and hyperspectral imaging techniques have been developed as a non-destructive method to monitor the distribution of residual water surrounding and within the cells. The distribution of vitrified residual water may contribute to desiccation resistance. Other types of thin liquid film reactors, such as a spinning disk bioreactor (SDBR), that enhance mass transfer by reducing liquid film thickness to \u3c100 ÎĽm with wave induced turbulent flow using centrifugal force (1000 x g) can be used in the future to further intensify continuous gas processing rates using biocomposite biocatalysts
The Nature of the Halo Population of NGC 5128 Resolved with NICMOS on the Hubble Space Telescope
We present the first infrared color-magnitude diagram (CMD) for the halo of a
giant elliptical galaxy. The CMD for the stars in the halo of NGC 5128
(Centaurus A) was constructed from HST NICMOS observations of the WFPC2 CHIP-3
field of Soria et al. (1996) to a 50% completeness magnitude limit of
[F160W]=23.8. This field is located at a distance of 08'50" (~9 kpc) south of
the center of the galaxy. The luminosity function (LF) shows a marked
discontinuity at [F160W]=20.0. This is 1-2 mag above the tip of the red giant
branch (TRGB) expected for an old population (~12 Gyr) at the distance modulus
of NGC 5128. We propose that the majority of stars above the TRGB have
intermediate ages (~2 Gyr), in agreement with the WFPC2 observations of Soria
et al. (1996). Five stars with magnitudes brighter than the LF discontinuity
are most probably due to Galactic contamination. The weighted average of the
mean giant branch color above our 50% completeness limit is
[F110W]-[F160W]=1.22+-0.08 with a dispersion of 0.19 mag. From our
artificial-star experiments we determine that the observed spread in color is
real, suggesting a real spread in metallicity. We estimate the lower and upper
bounds of the stellar metallicity range by comparisons with observations of
Galactic star clusters and theoretical isochrones. Assuming an old population,
we find that, in the halo field of NGC 5128 we surveyed, stars have
metallicities ranging from roughly 1% of solar at the blue end of the color
spread to roughly solar at the red end, with a mean of [Fe/H]=-0.76 and a
dispersion of 0.44 dex.Comment: Accepted for publication in AJ, 23 pages of text, 13 figures, uses
aastex v5.
High resolution infrared spectra of bulge globular clusters: Liller~1 and NGC 6553
Using the NIRSPEC spectrograph at Keck II, we have obtained echelle spectra
covering the range 1.5-1.8um for 2 of the brightest giants in Liller 1 and NGC
6553, old metal rich globular clusters in the Galactic bulge. We use spectrum
synthesis for the abundance analysis, and find [Fe/H]=-0.3 +/- 0.2 and
[O/H]=+0.3 +/- 0.2 dex. The composition of the clusters is similar to that of
field stars in the bulge and is consistent with a sceanrio in which the
clusters formed early, with rapid enrichment. We have dificulty achieveing a
good fit to the spectrum of NGC 6553 using either the low or the high values
recently reported in the literature, unless unusually large, or no
alpha-element enhancements are adopted, respectively.Comment: To appear in the Astronomical Journal, March 200
Combined Effects of Carbon and Nitrogen Source to Optimize Growth of Proteobacterial Methanotrophs
Methane, a potent greenhouse gas, and methanol, commonly called wood alcohol, are common by-products of modern industrial processes. They can, however, be consumed as a feedstock by bacteria known as methanotrophs, which can serve as useful vectors for biotransformation and bioproduction. Successful implementation in industrial settings relies upon efficient growth and bioconversion, and the optimization of culturing conditions for these bacteria remains an ongoing effort, complicated by the wide variety of characteristics present in the methanotroph culture collection. Here, we demonstrate the variable growth outcomes of five diverse methanotrophic strains – Methylocystis sp. Rockwell, Methylocystis sp. WRRC1, Methylosinus trichosporium OB3b, Methylomicrobium album BG8, and Methylomonas denitrificans FJG1 – grown on either methane or methanol, at three different concentrations, with either ammonium or nitrate provided as nitrogen source. Maximum optical density (OD), growth rate, and biomass yield were assessed for each condition. Further metabolite and fatty acid methyl ester (FAME) analyses were completed for Methylocystis sp. Rockwell and M. album BG8. The results indicate differential response to these growth conditions, with a general preference for ammonium-based growth over nitrate, except for M. denitrificans FJG1. Methane is also preferred by most strains, with methanol resulting in unreliable or inhibited growth in all but M. album BG8. Metabolite analysis points to monitoring of excreted formic acid as a potential indicator of adverse growth conditions, while the magnitude of FAME variation between conditions may point to strains with broader substrate tolerance. These findings suggest that methanotroph strains must be carefully evaluated before use in industry, both to identify optimal conditions and to ensure the strain selected is appropriate for the process of interest. Much work remains in addressing the optimization of growth strategies for these promising microorganisms since disregarding these important steps in process development could ultimately lead to inefficient or failed bioprocesses
First results of the ALOS PALSAR verification processor
Among the several applications that will take advantage of the newly available data from the ALOS PALSAR instrument, considerable interest is in the peculiar features that derive from the penetration and polarimetric capabilities of the system.
These capabilities, new for a single spaceborne sensor, need specific software tools for the processing of the different acquisition modes. This paper presents a verification processor, developed under ESA contract, for the generation of polarimetric, interferometric and polarimetric-interferometric geocoded products derived from ALOS PALSAR data.
The processor, developed with a modular approach, contains the following main elements:
- Phase-preserving fine resolution processor; - Phase-preserving ScanSAR processor;
- Interference removal tools;
- Polarimetric calibration tools;
- Polarimetric analysis tools;
- Fine resolution interferometric processor; - ScanSAR interferometric processor;
- Polarimetric-interferometric processor;
- Geocoding;
- Atmospheric modelling tools.
The processor architecture is presented; highlights are given on specific modules and algorithms. Early results are shown, in particular of the processing of polarimetric and polarimetric-interferometric data over different test sites
HST-NICMOS Observations of M31's Metal Rich Globular Clusters and Their Surrounding Fields: II. Results
We have obtained HST-NICMOS observations of five of M31's most metal rich
globular clusters: G1, G170, G174, G177 & G280. For the two clusters farthest
from the nucleus we statistically subtract the field population and estimate
metallicities using K-(J-K) color-magnitude diagrams (CMDs). Based on the
slopes of their infrared giant branches we estimate [Fe/H]=-1.22+/-0.43 for G1
and -0.15+/-0.37 for G280. We combine our infrared observations of G1 with two
epochs of optical HST-WFPC2 V-band data and identify at least one LPV based on
color and variability. The location of G1's giant branch in the K-(V-K) CMD is
very similar to that of M107, indicating a higher metallicity than our purely
infrared CMD: [Fe/H]=-0.9+/-0.2.
For the field surrounding G280, we estimate the metallicity to be -1.3 with a
spread of 0.5 from the slope and width of the giant branch. Based on the
numbers and luminosities of the brightest giants, we conclude that only a small
fraction of the stars in this field could be as young as 2 Gyr, while the
majority have ages closer to 10 Gyr.
The K-band luminosity functions (LFs) of the upper few magnitudes of G1 and
G280, as well as for the fields surrounding all clusters, are indistinguishable
from the LF measured in the bulge of our Galaxy. This indicates that these
clusters are very similar to Galactic clusters, and at least in the surrounding
fields observed, there are no significant populations of young luminous stars.Comment: AAS LaTeX v5.0, 17 pages. Submitted to the A
Down-Selection and Outdoor Evaluation of Novel, Halotolerant Algal Strains for Winter Cultivation
Algae offer promising feedstocks for the production of renewable fuel and chemical intermediates. However, poor outdoor winter cultivation capacity currently limits deployment potential. In this study, 300 distinct algal strains were screened in saline medium to determine their cultivation suitability during winter conditions in Mesa, Arizona. Three strains, from the genera Micractinium, Chlorella, and Scenedesmus, were chosen following laboratory evaluations and grown outdoors in 1000 L raceway ponds during the winter. Strains were down-selected based on doubling time, lipid and carbohydrate amount, final biomass accumulation capacity, cell size and phylogenetic diversity. Algal biomass productivity and compositional analysis for lipids and carbohydrates show successful outdoor deployment and cultivation under winter conditions for these strains. Outdoor harvest-yield biomass productivities ranged from 2.9 to 4.0 g/m2/day over an 18 days winter cultivation trial, with maximum productivities ranging from 4.0 to 6.5 g/m2/day, the highest productivities reported to date for algal winter strains grown in saline media in open raceway ponds. Peak fatty acid levels ranged from 9 to 26% percent of biomass, and peak carbohydrate levels ranged from 13 to 34% depending on the strain. Changes in the lipid and carbohydrate profile throughout outdoor growth are reported. This study demonstrates that algal strain screening under simulated outdoor environmental conditions in the laboratory enables identification of strains with robust biomass productivity and biofuel precursor composition. The strains isolated here represent promising winter deployment candidates for seasonal algal biomass production when using crop rotation strategies
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