8,368 research outputs found
Studies on the use of sulfites to control shrimp melanosis (Blackspot) (Presented at the 11th Annual Meeting of the Tropical and Subtropical Fisheries Technological Conference of the Americas, January 14, 1986, Tampa, Florida)
Shrimp melanosis, commonly known as 'blackspot' is a
harmless but objectionable surface dicoloration caused by
polyphenoloxidase enzyme systems which remain active during
refrigeration or ice storage. In the early 1950's sulfiting
agents, particularily sodium bisulfite was first introduced to prevent or inhibit melanosis, thus yielding a more valuable harvest (1). Such use of sulfites was 'prior sanctioned1 by the U.S. Food and Drug Administration (FDA) in 1956 (2). More recent FDA decisions reaffirmed this practice, (3) but continuing regulatory scrutiny could restrict or eliminate the application of sulfite on shrimp. The regulatory action is prompted by an increasing concern for adverse 'allergic' reactions most common amongst hyper-(sulfite) sensitive asthmatics. Thus work was initiated to find alternatives to replace or reduce the amount of sulfites required to inhibit
shrimp melanosis. This work would screen for possible
alternatives which would require subsequent verification with field tests and statistical evaluations. (21pp.
Externally heated protostellar cores in the Ophiuchus star-forming region
We present APEX 218 GHz observations of molecular emission in a complete
sample of embedded protostars in the Ophiuchus star-forming region. To study
the physical properties of the cores, we calculate HCO and c-CH
rotational temperatures, both of which are good tracers of the kinetic
temperature of the molecular gas. We find that the HCO temperatures range
between 16 K and 124 K, with the highest HCO temperatures toward the hot
corino source IRAS 16293-2422 (69-124 K) and the sources in the Oph A
cloud (23-49 K) located close to the luminous Herbig Be star S 1, which
externally irradiates the Oph A cores. On the other hand, the
c-CH rotational temperature is consistently low (7-17 K) in all
sources. Our results indicate that the c-CH emission is primarily
tracing more shielded parts of the envelope whereas the HCO emission (at
the angular scale of the APEX beam; 3600 au in Ophiuchus) mainly traces the
outer irradiated envelopes, apart from in IRAS 16293-2422, where the hot corino
emission dominates. In some sources, a secondary velocity component is also
seen, possibly tracing the molecular outflow.Comment: 19 pages, 9 figures, accepted for publication in Ap
The chiral and flavour projection of Dirac-Kahler fermions in the geometric discretization
It is shown that an exact chiral symmetry can be described for Dirac-Kahler
fermions using the two complexes of the geometric discretization. This
principle is extended to describe exact flavour projection and it is shown that
this necessitates the introduction of a new operator and two new structures of
complex. To describe simultaneous chiral and flavour projection, eight
complexes are needed in all and it is shown that projection leaves a single
flavour of chiral field on each.Comment: v2: 17 pages, Latex. 5 images eps. Added references, reformatted and
clarification of some point
Simple and accurate one-sided inference from signed roots of likelihood ratios
The authors propose two methods based on the signed root of the likelihood ratio statistic for one-sided testing of a simple null hypothesis about a scalar parameter in the presence of nuisance parameters. Both methods are third-order accurate and utilise simulation to avoid the need for onerous analytical calculations characteristic of competing saddlepoint procedures. Moreover, the new methods do not require specification of ancillary statistics. The methods respect the conditioning associated with similar tests up to an error of third order, and conditioning on ancillary statistics to an error of second order
Measurement of CHD on Titan at Submillimeter Wavelengths
We present the first radio/submillimeter detection of monodeuterated methane
(CHD) in Titan's atmosphere, using archival data from of the Atacama Large
Millimeter/submillimeter Array (ALMA). The and
transitions at 465.235 and 465.250 GHz ( mm) were measured at
significance levels of and , respectively. These two
lines were modeled using the Non-linear optimal Estimator for MultivariatE
spectral analySIS (NEMESIS) radiative transfer code to determine the
disk-averaged CHD volume mixing ratio = in Titan's
stratosphere (at altitudes km). By comparison with the CH vertical
abundance profile measured by Cassini-Huygens mass spectrometry, the resulting
value for D/H in CH is . This is consistent
with previous ground-based and in-situ measurements from the Cassini-Huygens
mission, though slightly lower than the average of the previous values.
Additional CHD observations at higher spatial resolution will be required
to determine a value truly comparable with the Cassini-Huygens CH
measurements, by measuring CHD with ALMA close to Titan's equator. In the
post-Cassini era, spatially resolved observations of CHD with ALMA will
enable the latitudinal distribution of methane to be determined, making this an
important molecule for further studies.Comment: 9 pages, 4 figure
Physics Of Eclipsing Binaries. II. Towards the Increased Model Fidelity
The precision of photometric and spectroscopic observations has been
systematically improved in the last decade, mostly thanks to space-borne
photometric missions and ground-based spectrographs dedicated to finding
exoplanets. The field of eclipsing binary stars strongly benefited from this
development. Eclipsing binaries serve as critical tools for determining
fundamental stellar properties (masses, radii, temperatures and luminosities),
yet the models are not capable of reproducing observed data well either because
of the missing physics or because of insufficient precision. This led to a
predicament where radiative and dynamical effects, insofar buried in noise,
started showing up routinely in the data, but were not accounted for in the
models. PHOEBE (PHysics Of Eclipsing BinariEs; http://phoebe-project.org) is an
open source modeling code for computing theoretical light and radial velocity
curves that addresses both problems by incorporating missing physics and by
increasing the computational fidelity. In particular, we discuss triangulation
as a superior surface discretization algorithm, meshing of rotating single
stars, light time travel effect, advanced phase computation, volume
conservation in eccentric orbits, and improved computation of local intensity
across the stellar surfaces that includes photon-weighted mode, enhanced limb
darkening treatment, better reflection treatment and Doppler boosting. Here we
present the concepts on which PHOEBE is built on and proofs of concept that
demonstrate the increased model fidelity.Comment: 60 pages, 15 figures, published in ApJS; accompanied by the release
of PHOEBE 2.0 on http://phoebe-project.or
EXTENSION EDUCATORS' SUPPLY OF RISK MANAGEMENT TRAINING TO FARMERS
A univariate Tobit model of extension educators' provision of risk management educational training was conducted in Mississippi, Texas, Indiana, and Nebraska. A complementary relationship exists between percent of time devoted to agricultural responsibilities and the provision of risk management training courses. The results indicate that, as extension educators perceive farmers to be more knowledgeable of risk management tools, their provision of risk management education decreases. On the other hand, the provision of risk management courses increase as extension educators perceive themselves as being more knowledgeable on the use of risk management tools.Teaching/Communication/Extension/Profession,
A Rare Case of Jejunal Arterio-Venous Fistula: Treatment with Superselective Catheter Embolization with a Tracker-18 Catheter and Microcoils
Arterio-venous fistulas may develop spontaneously, following trauma or infection, or be iatrogenic in nature. We present a rare case of a jejunal arterio- venous fistula in a 35-year-old man with a history of pancreatic head resection that had been performed two years previously because of chronic pancreatitis. The patient was admitted with acute upper abdominal pain, vomiting and an abdominal machinery-type bruit. The diagnosis of a jejunal arterio-venous fistula was established by MR imaging. Transfemoral angiography was performed to assess the possibility of catheter embolization. The angiographic study revealed a small aneurysm of the third jejunal artery, abnormal early filling of dilated jejunal veins and marked filling of the slightly dilated portal vein (13-14 mm). We considered the presence of segmental portal hypertension. The patient was treated with coil embolization in the same angiographic session. This case report demonstrates the importance of auscultation of the abdomen in the initial clinical examination. MR imaging and color Doppler ultrasound are excellent noninvasive tools in establishing the diagnosis. The role of interventional radiological techniques in the treatment of early portal hypertension secondary to jejunal arterio-venous fistula is discussed at a time when this condition is still asymptomatic. A review of the current literature is include
Confirming the impact of HIV/AIDS epidemics on household vulnerability in Asia: the case of Cambodia.
OBJECTIVES: This study explores the effects of HIV and AIDS on household economics and the social wellbeing of children in HIV-affected families in Cambodia. METHODS: A purposive sample of parents living with HIV and their children was selected from networks of people living with HIV. 'Nearest-neighbour' households served as the comparison group. Interviews were conducted with the parent and at least one child or adolescent in each household between October 2003 and January 2004. The urban/rural sample included 1000 households, 1000 adults, and 1443 children aged 6-17 years, inclusive, and was drawn from Phnom Penh, Battambang and Takeo provinces. RESULTS: Despite similar overall expenditures, HIV-affected households incurred proportionately larger expenditures on medical care and funerals. Income among case households was lower than comparison households. HIV-affected households were more likely to sell off assets, borrow from family members, take out loans, and ration medical care and food for children. Children in HIV-affected households reported eating fewer meals in a day, increased frequency of hunger, and increased household and employment responsibilities compared with comparison children. School enrollment rates were similar between pairs of households. CONCLUSION: The results add to growing evidence that HIV and AIDS contribute to increased vulnerability to poverty and increased burdens on families and children. This study corroborates findings from previous studies in Asia, while providing country-specific information to stakeholders in Cambodia. At this stage in the epidemic, policy makers should focus on implementing and evaluating mitigation interventions
Critical Phenomena Inside Global Monopoles
The gravitational collapse of a triplet scalar field is examined assuming a
hedgehog ansatz for the scalar field. Whereas the seminal work by Choptuik with
a single, strictly spherically symmetric scalar field found a discretely
self-similar (DSS) solution at criticality with echoing period ,
here a new DSS solution is found with period . This new critical
solution is also observed in the presence of a symmetry breaking potential as
well as within a global monopole. The triplet scalar field model contains
Choptuik's original model in a certain region of parameter space, and hence his
original DSS solution is also a solution. However, the choice of a hedgehog
ansatz appears to exclude the original DSS.Comment: 5 pages, 5 figure
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