40,949 research outputs found
Bimaximal Mixing in an SO(10) Minimal Higgs Model
An SO(10) SUSY GUT model was previously presented based on a minimal set of
Higgs fields. The quark and lepton mass matrices derived fitted the data
extremely well and led to large mixing of muon- and tau-neutrinos in agreement
with the atmospheric neutrino data and to the small-angle MSW solution for the
solar neutrinos. Here we show how a slight modification leading to a non-zero
up quark mass can result in bimaximal mixing for the atmospheric and solar
neutrinos. The "just-so" vacuum solution is slightly favored over the
large-angle MSW solution on the basis of the hierarchy required for the
right-handed Majorana matrix and the more nearly-maximal mixing angles
obtained.Comment: 10 pages, LaTeX, several references adde
Higher-dimensional operators in SUSY SO(10) GUT models
SO(10) GUT models with only small Higgs fields use higher-dimensional
operators to generate realistic fermion mass matrices. In particular, a Higgs
field in the spinor representation, 16^d_H, acquires a weak scale vev. We
include the weak vev of the corresponding field \bar{16}^u_H and investigate
the effect on two successful models, one by Albright and Barr (AB) and another
by Babu, Pati and Wilczek (BPW). We find that the BPW model is a particular
case within a class of models with identical fermion masses and mixings. In
contrast, we expect corrections to the parameters of AB-type models.Comment: 3 page
Forecasting the Progression of Alzheimer's Disease Using Neural Networks and a Novel Pre-Processing Algorithm
Alzheimer's disease (AD) is the most common neurodegenerative disease in
older people. Despite considerable efforts to find a cure for AD, there is a
99.6% failure rate of clinical trials for AD drugs, likely because AD patients
cannot easily be identified at early stages. This project investigated machine
learning approaches to predict the clinical state of patients in future years
to benefit AD research. Clinical data from 1737 patients was obtained from the
Alzheimer's Disease Neuroimaging Initiative (ADNI) database and was processed
using the "All-Pairs" technique, a novel methodology created for this project
involving the comparison of all possible pairs of temporal data points for each
patient. This data was then used to train various machine learning models.
Models were evaluated using 7-fold cross-validation on the training dataset and
confirmed using data from a separate testing dataset (110 patients). A neural
network model was effective (mAUC = 0.866) at predicting the progression of AD
on a month-by-month basis, both in patients who were initially cognitively
normal and in patients suffering from mild cognitive impairment. Such a model
could be used to identify patients at early stages of AD and who are therefore
good candidates for clinical trials for AD therapeutics.Comment: 10 pages; updated acknowledgement
SO(10) GUT Models and Their Present Success in Explaining Mass and Mixing Data
Some features of SO(10) GUT models are reviewed, and a number of such models
in the literature are compared. While some have been eliminated by recent
neutrino data, others are presently successful in explaining the quark and
lepton mass and mixing data. A short description of one very predictive model
is given which illustrates some of the features discussed. Future tests of the
models are pointed out including one which contrasts sharply with those models
based on an type symmetry.Comment: 9 pages, paper presented at the Neutrinos and Implications for
Physics Beyond the Standard Model Conference, SUNY at Stony Brook, October
11-13, 200
Device separates hydrogen from solution in water at ambient temperatures
Separator decreases the partial pressure of hydrogen gas dissolved in the water produced by fuel cells containing an alkaline electrolyte. The unit eliminates the hazards associated with the release of hydrogen from water solution when the hydrostatic pressure is rapidly decreased
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