948 research outputs found
Stochastic Binary Modeling of Cells in Continuous Time as an Alternative to Biochemical Reaction Equations
We have developed a coarse-grained formulation for modeling the dynamic
behavior of cells quantitatively, based on stochasticity and heterogeneity,
rather than on biochemical reactions. We treat each reaction as a
continuous-time stochastic process, while reducing each biochemical quantity to
a binary value at the level of individual cells. The system can be analytically
represented by a finite set of ordinary linear differential equations, which
provides a continuous time course prediction of each molecular state. In this
letter, we introduce our formalism and demonstrate it with several examples.Comment: 10pages, 3 figure
Drag Force, Jet Quenching, and AdS/QCD
In this note, two important transport observables in the RHIC experiment,
relaxation time constant and jet quenching parameter, are calculated from an
AdS/QCD model. A quark moving in the viscous medium such as the
Quark-Gluon-Plasma is modelled by an open string whose end point travels on the
boundary of a deformed AdS_5 black hole. The correction introduced via the
deformed AdS_5 is believed to help us better understand the data which is
expected to be measured in the RHIC.Comment: 13 pages, 4 figures, revised for PRD. Some comments have been added
below Eq.(34) to avoid a misreading in comparison between our result and
CFT'
Zero-norm states and stringy symmetries
We identify spacetime symmetry charges of 26D open bosonic string theory from
an infinite number of zero-norm states (ZNS) with arbitrary high spin in the
old covariant first quantized string spectrum. We give various evidences to
support this identification. These include massive sigma-model calculation,
Witten string field theory calculation, 2D string theory calculation and, most
importantly, three methods of high-energy stringy scattering amplitude
calculations. The last calculations explicitly prove Gross's conjectures in
1988 on high energy symmetry of string theory.Comment: 6 pages. Talks presented by Jen-Chi Lee at XXVIII Spanish Relativity
Meeting (ERE2005),"A Century of Relativity Physics",Oviedo,Spain,6-10 Sep
2005 and "4th Meeting on constrained Dynamics and Quantum Gravity",Cala
Gonone,Sardinia,Italy,12-16 Sep 2005. To appear in the Journal of Physics:
Conference Serie
"Unknown" Students on College Campuses: An Exploratory Analysis
Examines data from three campuses to identify college students falling into the "race/ethnicity unknown" category. Provides recommendations for increasing demographic accuracy, and measuring the success of underrepresented students in higher education
Heterotic E6 GUTs and Partition Functions
The E6 grand unified theory is an attractive candidate intermediate theory
between the standard model and string theory. However, only one E6 grand
unified model with three generations and at least one adjoint Higgs field has
been derived from string theory in the literature, and this model is
phenomenologically unsatisfactory. Recently, in arXiv:1012.1690, we have
constructed two new such E6 grand unified models in heterotic asymmetric
orbifolds. Although our new models themselves cannot resolve the unsatisfactory
point in the previous model, our discovery raises hopes that one can construct
many other such models in this framework and find better models. Here, by
giving partition functions explicitly, we explain the details of our
construction. Utilizing the lattice engineering technique and the diagonal
embedding method, we can construct models systematically. We hope that these
techniques and the details of our construction will lead to more
phenomenologically desirable models.Comment: 42 pages, 2 figures, v2: text rearranged, version to appear in JHE
The Effects of Siltation on Embryonic Mortality of Trout
(print) 28 leaves : ill. ; 28 cm.In this research project, we tested the hypothesis that siltation in streams eliminates natural reproduction by increasing mortality during embryonic development. We knew that several environmental factors (temperature, dissolved oxygen, and flow rates) affected
embryonic development. These factors all change with siltation in streams, but the interaction of these factors with silt needed more experimentation. If we could determine the extent to which silt
alone affected embryo mortality, we could design procedures to improve trout reproduction in silted streams. In the first 18 months of our project, we tried to define the critical period of susceptibility
of trout embryos to siltation. Our findings were that siltation alone did not influence embryonic development. During the remaining
six months of the project we explored the effects of siltation on spawning behavior and initiated a new project to determine
the feasibility of selecting trout strains, which would be more tolerant to the marginal conditions in Northeastern Ohi
High-energy zero-norm states and symmetries of string theory
High-energy limit of zero-norm states (HZNS) in the old covariant first
quantized (OCFQ) spectrum of the 26D open bosonic string, together with the
assumption of a smooth behavior of string theory in this limit, are used to
derive infinitely many linear relations among the leading high-energy, fixed
angle behavior of four point functions of different string states. As a result,
ratios among all high-energy scattering amplitudes of four arbitrary string
states can be calculated algebraically and the leading order amplitudes can be
expressed in terms of that of four tachyons as conjectured by Gross in 1988. A
dual calculation can also be performed and equivalent results are obtained by
taking the high-energy limit of Virasoro constraints. Finally, as a consistent
sample calculation, we compute all high-energy scattering amplitudes of three
tachyons and one massive state at the leading order by saddle-point
approximation to justify our results.Comment: 10 pages, no figure, modifications of text and reference
Prevalence of Anderson-Fabry disease in male patients with late onset hypertrophic cardiomyopathy
Background-Although studies have suggested that "late-onset" hypertrophic cardiomyopathy (HCM) may be caused by sarcomeric protein gene mutations, the cause of HCM in the majority of patients is unknown. This study determined the prevalence of a potentially treatable cause of hypertrophy, Anderson-Fabry disease, in a HCM referral population.Methods and Results-Plasma alpha-galactosidase A (alpha-Gal) was measured in 79 men with HCM who were diagnosed at greater than or equal to40 years of age (52.9 +/- 7.7 years; range, 40-71 years) and in 74 men who were diagnosed at <40 years (25.9 +/- 9.2 years; range, 8-39 years). Five patients (6.3%) with late-onset disease and 1 patient (1.4%) diagnosed at <40 years had low alpha-Gal activity. Of these 6 patients, 3 had angina, 4 were in New York Heart Association class 2, 5 had palpitations, and 2 had a history of syncope. Hypertrophy was concentric in 5 patients and asymmetric in 1 patient. One patient had left ventricular outflow tract obstruction. All patients with low alpha-Gal activity had alpha-Gal gene mutations.Conclusion-Anderson-Fabry disease should be considered in all cases of unexplained hypertrophy. Its recognition is important given the advent of specific replacement enzyme therapy
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