998 research outputs found
A late, infrared flash from the afterglow of GRB 050319
We report the detection of a bright, near-infrared flash from the afterglow
of GRB 050319, 6.15 hours after the burst. The IR flash faded rapidly from
J=13.12 mag. to J > 15.5 mag. in about 4 minutes. There are no reported
simultaneous observations at other wavelengths making it an unique event. We
study the implications of its late timing in the context of current theoretical
models for GRB afterglows.Comment: Accepted in ApJ (Letters
Evaluation of bread crumbs as a potential carbon source for the growth of Thraustochytrid species for oil and omega-3 production
The utilization of food waste by microorganisms to produce omega-3 fatty acids or biofuel is a potentially low cost method with positive environmental benefits. In the present study, the marine microorganisms Thraustochytrium sp. AH-2 and Schizochytrium sp. SR21 were used to evaluate the potential of breadcrumbs as an alternate carbon source for the production of lipids under static fermentation conditions. For the Thraustochytrium sp. AH-2, submerged liquid fermentation with 3% glucose produced 4.3 g/L of biomass and 44.16 mg/g of saturated fatty acids after seven days. Static fermentation with 0.5% and 1% breadcrumbs resulted in 2.5 and 4.7 g/L of biomass, and 42.4 and 33.6 mg/g of saturated fatty acids, respectively. Scanning electron microscopic (SEM) studies confirmed the growth of both strains on breadcrumbs. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy for both strains were consistent with the utilization of breadcrumbs for the production of unsaturated lipids, albeit at relatively low levels. The total lipid yield for static fermentation with bread crumbs was marginally lower than that of fermentation with glucose media, while the yield of unsaturated fatty acids was considerably lower, indicating that static fermentation may be more appropriate for the production of biodiesel than for the production of omega-3 rich oils in these strains
Fock space exploration by angle resolved transmission through quantum diffraction grating of cold atoms in an optical lattice
Light transmission or diffraction from different quantum phases of cold atoms
in an optical lattice has recently come up as a useful tool to probe such ultra
cold atomic systems. The periodic nature of the optical lattice potential
closely resembles the structure of a diffraction grating in real space, but
loaded with a strongly correlated quantum many body state which interacts with
the incident electromagnetic wave, a feature that controls the nature of the
light transmission or dispersion through such quantum medium. In this paper we
show that as one varies the relative angle between the cavity mode and the
optical lattice, the peak of the transmission spectrum through such cavity also
changes reflecting the statistical distribution of the atoms in the illuminated
sites. Consequently the angle resolved transmission spectrum of such quantum
diffraction grating can provide a plethora of information about the Fock space
structure of the many body quantum state of ultra cold atoms in such an optical
cavity that can be explored in current state of the art experiments.Comment: 40 double spaced, single column pages, 40 .eps figures, accepted for
publication in Physical Review
Measuring the global 21-cm signal with the MWA-II: improved characterisation of lunar-reflected radio frequency interference
Radio interferometers can potentially detect the sky-averaged signal from the
Cosmic Dawn (CD) and the Epoch of Reionisation (EoR) by studying the Moon as a
thermal block to the foreground sky. The first step is to mitigate the
Earth-based RFI reflections (Earthshine) from the Moon, which significantly
contaminate the FM band MHz, crucial to CD-EoR science. We
analysed MWA phase-I data from MHz at kHz resolution to
understand the nature of Earthshine over three observing nights. We took two
approaches to correct the Earthshine component from the Moon. In the first
method, we mitigated the Earthshine using the flux density of the two
components from the data, while in the second method, we used simulated flux
density based on an FM catalogue to mitigate the Earthshine. Using these
methods, we were able to recover the expected Galactic foreground temperature
of the patch of sky obscured by the Moon. We performed a joint analysis of the
Galactic foregrounds and the Moon's intrinsic temperature
while assuming that the Moon has a constant thermal temperature throughout
three epochs. We found to be at and
using the first and the second methods, respectively,
and the best-fit values of the Galactic spectral index were found to
be within the uncertainty level when compared with the global sky model.
Compared with our previous work, these results improved constraints on the
Galactic spectral index and the Moon's intrinsic temperature. We also simulated
the Earthshine at the MWA between November-December 2023 to find suitable
observing times less affected by the Earthshine. Such time windows can be used
to schedule future observations of CD-EoR using the MWA.Comment: 17 pages, 14 figures and 5 tables, submitted to PAS
Patronin-mediated minus end growth is required for dendritic microtubule polarity.
Microtubule minus ends are thought to be stable in cells. Surprisingly, in Drosophila and zebrafish neurons, we observed persistent minus end growth, with runs lasting over 10 min. In Drosophila, extended minus end growth depended on Patronin, and Patronin reduction disrupted dendritic minus-end-out polarity. In fly dendrites, microtubule nucleation sites localize at dendrite branch points. Therefore, we hypothesized minus end growth might be particularly important beyond branch points. Distal dendrites have mixed polarity, and reduction of Patronin lowered the number of minus-end-out microtubules. More strikingly, extra Patronin made terminal dendrites almost completely minus-end-out, indicating low Patronin normally limits minus-end-out microtubules. To determine whether minus end growth populated new dendrites with microtubules, we analyzed dendrite development and regeneration. Minus ends extended into growing dendrites in the presence of Patronin. In sum, our data suggest that Patronin facilitates sustained microtubule minus end growth, which is critical for populating dendrites with minus-end-out microtubules
Antibacterial property of neem nanoemulsion against Vibrio anguillarium infection in Asian sea bass (Lates calcarifer)
1222-1226Fish vibriosis is among the most common diseases that is caused by a bacteria belonging to the genus Vibrio (Vibrio anguillarium). It causes considerable economic loss in the commercial cultivation of Asian sea bass (Lates calcarifer). The resistance of microorganisms to antibiotics has resulted in a growing need for developing a new antibacterial therapy that is effective in aquaculture. The aim of this study is to develop neem nanoemulsion with antibacterial activity against V. anguillarium to identify a possible alternative to the commonly used antibiotics in aquaculture. Neem nanoemulsion was prepared and the effectiveness was studied both in vitro and in vivo (agar well diffusion assay and artificial infection). Injection and immersion challenge of neem nanoemulsion formulated the fish less susceptible to V. anguillarium infection. The results confirmed the potential use of neem nanoemulsion as a source of antibacterial compounds or as a health-promoting medicine for fish culture
A case of valproate induced non-hepatic hyperammonemic encephalopathy
Sodium valproate is a broad spectrum anticonvulsant. Valproate induced hyperammonemic encephalopathy with normal liver function is a serious, but less common entity
A multi-period game-theoretic approach to market fairness in oligopolies
Contemporary process industries are constantly confronted with volatile
market conditions that jeopardise their financial sustainability. While mature
markets transition to oligopoly structures, the supply chain operation should
adapt to a more customer-centric focus. Key issues related to the modelling and
impact of the related contractual agreements between firms and customers remain
largely unexplored. In the present work, we examine the problem of fair
customer allocation in oligopolies under different contractual agreements
within a multi-period setting. We consider an ensemble of contract types that
vary in terms of pricing mechanisms and duration. The role of fairness is
examined following the social welfare and Nash bargaining scheme. In the latter
case, the overall problem is formulated as an MINLP. For its efficient solution
we employ a piecewise linearisation strategy based on special-ordered sets. The
impact of the different fairness schemes on the optimal customer allocation is
evaluated via two case studies from the industrial gases market
In vivo evaluation of PhiC31 recombinase activity using a self-excision cassette
Gene targeting allows precise tailoring of the mouse genome such that desired modifications can be introduced under precise temporal and spatial control. This can be achieved through the use of site-specific recombinases, which mediate deletion or inversion of genomic DNA flanked by recombinase-specific recognition sites, coupled with gene targeting to introduce the recombinase recognition sites at the desired genomic locations within the mouse genome. The introduction of multiple modifications at the same locus often requires use of multiple recombination systems. The most commonly used recombination system is Cre/lox. We here evaluated in vivo the ability of PhiC31 phage integrase to induce a genomic deletion in mouse. We engineered a self-excision cassette, modeled after one previously designed for Cre, containing a positive selection marker and PhiC31 driven by a testis-specific promoter, all flanked by PhiC31 specific attP/B sites. We found in vivo PhiC31 mediated self-excision in 38% of transmitted alleles, although 18% of these showed evidence of imprecise deletion. Furthermore, in the 69% of un-recombined cassettes, sequence analysis revealed that PhiC31 mediated an intra-molecular deletion of the attB site preventing any subsequent recombination. This study demonstrates that PhiC31 can be used to automatically remove Neo, in the male chimera germline, although it is not as efficient or as accurate as Cre
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