836 research outputs found
Early nutrition causes persistent effects on pheasant morphology
Differences in growth conditions during early ontogeny have been suggested to cause permanent effects on the morphology and quality of birds. Yearly variation in growth conditions could thus result in morphological and quality differences between cohorts. In this study, we investigated the effect of small differences in the dietary protein content of captive ring-necked pheasants (Phasianus colchicus) during their first 8 wk posthatching. An experimental increase of the proportion of dietary protein during the first 3 wk of life accelerated growth, whereas a similar manipulation during the following 5 wk had only a limited effect. Compensatory growth during the postexperimental period equalized the size of chicks from different experimental treatments. However, a difference in tarsus length resulting from experimental treatment during the first 3 wk remained into adulthood. Furthermore, the protein content of the diet during the first 3 wk had an effect on the degree of fluctuating asymmetry in tarsus length, suggesting persistent effects on the quality of birds. The results of this study may explain size differences between cohorts that exist in pheasants and may also provide a link between the use of pesticides in agriculture and population effects on pheasants
The Effective Matter Potential for Highly Relativistic Neutrinos
We investigate matter effects on highly relativistic neutrinos. The
self-energy of neutrinos is determined in an electron or neutrino background
taking into account resonance and finite width effects of the gauge bosons. We
find minor changes compared to the formerly used formula for the propagator
function and large deviations of the effective width from the decay width of
the gauge bosons considering higher moments of the electron or neutrino
distribution function.Comment: 10 pages, 4 figures, latex. Final version published in Phys. Lett.
Triplet Leptogenesis in Left-Right Symmetric Seesaw Models
We discuss scalar triplet leptogenesis in a specific left-right symmetric
seesaw model. We show that the Majorana phases that are present in the model
can be effectively used to saturate the existing upper limit on the
CP-asymmetry of the triplets. We solve the relevant Boltzmann equations and
analyze the viability of triplet leptogenesis. It is known for this kind of
scenario that the efficiency of leptogenesis is maximal if there exists a
hierarchy between the branching ratios of the triplet decays into leptons and
Higgs particles. We show that triplet leptogenesis typically favors branching
ratios with not too strong hierarchies, since maximal efficiency can only be
obtained at the expense of suppressed CP-asymmetries.Comment: 16 pages, 5 figures, published versio
Non-standard neutrino interactions in the Zee-Babu model
We investigate non-standard neutrino interactions (NSIs) in the Zee--Babu
model. The size of NSIs predicted by this model is obtained from a full scan
over the parameter space, taking into account constraints from low-energy
experiments such as searches for lepton flavor violation (LFV) and the
requirement to obtain a viable neutrino mass matrix. The dependence on the
scale of new physics as well as on the type of the neutrino mass hierarchy is
discussed. We find that NSIs at the source of a future neutrino factory may be
at an observable level in the nu_e to nu_tau and/or nu_mu to nu_tau channels.
In particular, if the doubly charged scalar of the model has a mass in reach of
the LHC and if the neutrino mass hierarchy is inverted, a highly predictive
scenario is obtained with observable signals at the LHC, in upcoming neutrino
oscillation experiments, in LFV processes, and for NSIs at a neutrino factory.Comment: 9 pages, 4 figure
Stability and leptogenesis in the left-right symmetric seesaw mechanism
We analyze the left-right symmetric type I+II seesaw mechanism, where an
eight-fold degeneracy among the mass matrices of heavy right-handed neutrinos
M_R is known to exist. Using the stability property of the solutions and their
ability to lead to successful baryogenesis via leptogenesis as additional
criteria, we discriminate among these eight solutions and partially lift their
eight-fold degeneracy. In particular, we find that viable leptogenesis is
generically possible for four out of the eight solutions.Comment: 25 pages, 11 figures, latex; minor changes, published versio
The Hyperlinked Scandinavian News Ecology. The unequal terms forged by the structural properties of digitalisation
Small bowel enteroclysis with magnetic resonance imaging and computed tomography in patients with failed and uncertain passage of a patency capsule
<p>Abstract</p> <p>Background</p> <p>Video capsule enteroscopy (VCE) has revolutionized small bowel imaging, enabling visual examination of the mucosa of the entire small bowel, while MR enteroclysis (MRE) and CT enteroclysis (CTE) have largely replaced conventional barium enteroclysis. A new indication for MRE and CTE is the clinical suspicion of small bowel strictures, as indicated by delayed or non-delivery of a test capsule given before a VCE examination, to exclude stenosis. The aim of this study was to determine the clinical value of subsequent MRE and CTE in patients in whom a test capsule did not present itself in due time.</p> <p>Methods</p> <p>Seventy-five consecutive patients were identified with a delayed or unnoticed delivery of the test capsule. Seventy patients consented to participate and underwent MRE (44) or CTE (26). The medical records and imaging studies were retrospectively reviewed and symptoms, laboratory results and imaging findings recorded.</p> <p>Results</p> <p>Lesions compatible with Crohns disease were shown by MRE in 5 patients, by CTE in one and by VCE in four, one of whom had lesions on MRE. In patients without alarm symptoms and findings (weight loss, haematochezia, anaemia, nocturnal diarrheoa, ileus, fistula, abscess and abnormal blood tests) imaging studies did not unveil any such lesion. VCE's were performed in only 20 patients, mainly younger than 50 years of age, although no stenotic lesion was shown by MRE and CTE. In the remaining 50 patients no VCE or other endoscopic intervention was performed indicating that the referring physician was content with the diagnostic information from MRE or CTE.</p> <p>Conclusion</p> <p>The diagnostic value of MRE and CTE is sufficient for clinical management of most patients with suspected small bowel disease, and thus VCE may be omitted or at least postponed for later usage.</p
Higher spin AdS_3 holography with extended supersymmetry
We propose a holographic duality between a higher spin AdS_3 gravity with
so(p) extended supersymmetry and a large N limit of a 2-dimensional
Grassmannian-like model with a specific critical level k=N and a non-diagonal
modular invariant. As evidence, we show the match of one-loop partition
functions. Moreover, we construct symmetry generators of the coset model for
low spins which are dual to gauge fields in the supergravity. Further, we
discuss a possible relation to superstring theory by noticing an N=3
supersymmetry of critical level model at finite k,N. In particular, we examine
BPS states and marginal deformations. Inspired by the supergravity side, we
also propose and test another large N CFT dual obtained as a Z_2 automorphism
truncation of a similar coset model, but at a non-critical level.Comment: 44 pages, published versio
Red clover for silage: management impacts on herbage yield, nuitritive value, ensilability and persistence, and relativity to perennial ryegrass
This six year experiment quantified the impacts of management factors on red clover yield, persistence, nutritive value and ensilability, and compared these to perennial ryegrass receiving inorganic N fertiliser. Within a randomised complete block design, field plots were used to evaluate a 2 (cultivar; Merviot and Ruttinova) x 2 (alone or with perennial ryegrass) x 2 (0 and 50 kg fertiliser N/ha in mid March) x 2 (harvest schedule) combination of factors relating to red clover, and a 2 (harvest schedule) x 4 (0, 50, 100 and 150 kg N/ha for each cut) combination of factors relating to perennial ryegrass. The Early and Late harvest schedules both involved four cuts per year but commenced a fortnight apart. Red clover treatments averaged 14,906 kg dry matter/ha per year. There was no yield decline evident across years despite a decline in the proportion of red clover. The Early harvest schedule and sowing ryegrass with red clover increased herbage yield and digestibility. March application of fertiliser N to red clover treatments reduced annual yield. Early harvest schedule increased and both fertiliser N and sowing with ryegrass decreased the proportion of red clover. Sowing with ryegrass improved indices of ensilability but reduced crude protein. Both red clover cultivars had similar performance characteristics. A selected red clover-based treatment, considered to exhibit superior overall production characteristics, out-yielded perennial ryegrass plus fertiliser N in mid-season. However, it had poorer digestibility and ensilability indices
MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations
The recently observed event excess in MiniBooNE anti-neutrino data is in
agreement with the LSND evidence for electron anti-neutrino appearance. We
propose an explanation of these data in terms of a (3+1) scheme with a sterile
neutrino including non-standard neutrino interactions (NSI) at neutrino
production and detection. The interference between oscillations and NSI
provides a source for CP violation which we use to reconcile different results
from neutrino and anti-neutrino data. Our best fit results imply NSI at the
level of a few percent relative to the standard weak interaction, in agreement
with current bounds. We compare the quality of the NSI fit to the one obtained
within the (3+1) and (3+2) pure oscillation frameworks. We also briefly comment
on using NSI (in an effective two-flavour framework) to address a possible
difference in neutrino and anti-neutrino results from the MINOS experiment.Comment: 28 pages, 9 figures, discussion improved, new appendix added,
conclusions unchange
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