2,102 research outputs found
Beta decays with momentum space Majorana spinors
We construct and apply to beta decays a truly neutral local quantum field
that is entirely based upon momentum space Majorana spinors. We make the
observation that theory with momentum space Majorana spinors of real C parities
is equivalent to Dirac's theory. For imaginary C parities, the neutrino mass
can drop from the single beta decay trace and reappear in 0\nu \beta \beta, a
curious and in principle experimentally testable signature for a non-trivial
impact of Majorana framework in experiments with polarized sources.Comment: 7 pages, 1 figure; needs svjour.cls, svepj.cl
The infrared and molecular environment surrounding the Wolf-Rayet star WR130
We present a study of the molecular CO gas and mid/far infrared radiation
arising from the environment surrounding the Wolf-Rayet (W-R) star 130. We use
the multi-wavelength data to analyze the properties of the dense gas and dust,
and its possible spatial correlation with that of Young Stellar Objects (YSOs).
We use CO J=1-0 data from the FCRAO survey as tracer of the molecular gas, and
mid/far infrared data from the recent WISE and Herschel space surveys to study
the dust continuum radiation and to identify a population of associated
candidate YSOs. The spatial distribution of the molecular gas shows a ring-like
structure very similar to that observed in the HI gas, and over the same
velocity interval. The relative spatial distribution of the HI and CO
components is consistent with a photo-dissociation region. We have identified
and characterized four main and distinct molecular clouds that create this
structure. Cold dust is coincident with the dense gas shown in the CO
measurements. We have found several cYSOs that lie along the regions with the
highest gas column density, and suggest that they are spatially correlated with
the shell. These are indicative of regions of star formation induced by the
strong wind and ionization of the WR star.Comment: 15 pages, 12 figures, 6 Tables. Accepted for publication in MNRA
Is the inclusion of animal source foods in fortified blended foods justified?
Fortified blended foods (FBF) are used for the prevention and treatment of moderate acute malnutrition (MAM) in nutritionally vulnerable individuals, particularly children. A recent review of FBF recommended the addition of animal source food (ASF) in the form of whey protein concentrate (WPC), especially to corn-soy blends. The justification for this recommendation includes the potential of ASF to increase length, weight, muscle mass accretion and recovery from wasting, as well as to improve protein quality and provide essential growth factors. Evidence was collected from the following four different types of studies: (1) epidemiological; (2) ASF versus no intervention or a low-calorie control; (3) ASF versus an isocaloric non-ASF; and (4) ASF versus an isocaloric, isonitrogenous non-ASF. Epidemiological studies consistently associated improved growth outcomes with ASF consumption; however, little evidence from isocaloric and isocaloric, isonitrogenous interventions was found to support the inclusion of meat or milk in FBF. Evidence suggests that whey may benefit muscle mass accretion, but not linear growth. Overall, little evidence supports the costly addition of WPC to FBFs. Further, randomized isocaloric, isonitrogenous ASF interventions with nutritionally vulnerable children are needed
Expanded Very Large Array Observations of the Nebula Around G79.29+0.46
We have observed the radio nebula surrounding the Galactic luminous blue variable candidate G79.29+0.46 with the Expanded Very Large Array (EVLA) at 6 cm. These new radio observations allow a morphological comparison between the radio emission, which traces the ionized gas component, and the mid-IR emission, a tracer of the dust component. The InfraRed Array Camera (8 μm) and the Multiband Imaging Photometer for Spitzer (24 μm and 70 μm) images have been reprocessed and compared with the EVLA map. We confirm the presence of a second shell at 24 μm and also provide evidence for its detection at 70 μm. The differences between the spatial morphology of the radio and mid-IR maps indicate the existence of two dust populations, the cooler one emitting mostly at longer wavelengths. Analysis of the two dusty, nested shells have provided us with an estimate of the characteristic timescales for shell ejection, providing important constraints for stellar evolutionary models. Finer details of the ionized gas distribution can be appreciated thanks to the improved quality of the new 6 cm image, most notably the highly structured texture of the nebula. Evidence of interaction between the nebula and the surrounding interstellar medium can be seen in the radio map, including brighter features that delineate regions where the shell structure is locally modified. In particular, the brighter filaments in the southwest region appear to frame the shocked southwestern clump reported from CO observations
The North American and Pelican Nebulae I. IRAC Observations
We present a 9 deg^2 map of the North American and Pelican Nebulae regions
obtained in all four IRAC channels with the Spitzer Space Telescope. The
resulting photometry is merged with that at JHKs from 2MASS and a more
spatially limited survey from previous ground-based work. We use a
mixture of color- color diagrams to select a minimally contaminated set of more
than 1600 objects that we claim are young stellar objects (YSOs) associated
with the star forming region. Because our selection technique uses IR excess as
a requirement, our sample is strongly biased against inclusion of Class III
YSOs. The distribution of IRAC spectral slopes for our YSOs indicates that most
of these objects are Class II, with a peak towards steeper spectral slopes but
a substantial contribution from a tail of flat spectrum and Class I type
objects. By studying the small fraction of the sample that is optically
visible, we infer a typical age of a few Myr for the low mass population. The
young stars are clustered, with about a third of them located in eight clusters
that are located within or near the LDN 935 dark cloud. Half of the YSOs are
located in regions with surface densities higher than 1000 YSOs / deg^2. The
Class I objects are more clustered than the Class II stars.Comment: 16 pages, 12 figures, ApJ In pres
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