7,519 research outputs found
Molecular Diagnostics in Colorectal Cancer
Colorectal cancer (CRC) presents in one of three patterns: sporadic colorectal cancer in those without a family history (65-85%); those with a family history (familial CRC) 10-25% of cases; inherited CRC accounting for less of 10% cases and presents as well-characterized cancer predisposition syndromes including Lynch syndrome (hereditary non-polyposis colorectal cancer/HNPCC) which comprises about 1-5% of all colorectal cancer, and multiple polyps CRC, which includes familial adenomatous polyposis (FAP,1%), rare CRC syndrome < 0.1 %). Many efforts have been made to discover the genetic and molecular features of CRC, and there is more evidence that these features determine the prognosis and response to treatment. Colorectal cancer (CRC) is a heterogeneous disease, with three known major molecular groups. The most common is the chromosomal instability group, characterized by an accumulation of mutations in specific oncogens and tumor suppressor genes. The second is the microsatellite instability group, caused by the dysfunction of deoxyribonucleic acid (DNA) mismatch repair genes leading to genetic hypermutability. The CpG island methylation phenotype (CIMP) is the third group, distinguished by hypermethylation. In this review we would like to provide an up-to-date overview of molecular genetic aspects of CRC that are currently important and should guide clinical practice in colorectal cancer in the diagnosis and selection of therapy
Effective coping with cyberbullying in boys and girls: the mediating role of self-awareness, responsible decision-making, and social support
There is sufficient evidence on the negative consequences of cyberbullying victimisation depending on the coping styles. Social support seeking is among the most effective strategies for coping with cybervictimisation, but it is scarcely used. The robust Maximum Likelihood (ML) method was used to test the potential mediating role of individual (self-awareness, and responsible decision-making) and contextual variables (self-perceived parental and peer support) in the relationship between cybervictimisation and social support seeking in boys and girls. This cross-sectional study collected data from 1,276 Spanish secondary school students (51.2% boys, 48.8% girls) aged 11-18 (M = 13.88, SD = 1.42). Structural equation modelling (SEM) results pointed out responsible decision-making and self-perceived parental support as relevant mediating factors for girls. By contrast, the model was not significant for boys. These findings highlight the importance of both individual and contextual variables in helping adolescents cope with cyberaggressions, considering gender differences
Formation and kinetics of transient metastable states in mixtures under coupled phase ordering and chemical demixing
We present theory and simulation of simultaneous chemical demixing and phase
ordering in a polymer-liquid crystal mixture in conditions where isotropic-
isotropic phase separation is metastable with respect to isotropic-nematic
phase transition. It is found that mesophase formation proceeds by a transient
metastable phase that surround the ordered phase, and whose lifetime is a
function of the ratio of diffusional to orientational mobilities. It is shown
that kinetic phase ordering in polymer-mesogen mixtures is analogous to kinetic
crystallization in polymer solutions.Comment: 17 pages, 5 figures accepted for publication in EP
An Extension of the Fluctuation Theorem
Heat fluctuations are studied in a dissipative system with both mechanical
and stochastic components for a simple model: a Brownian particle dragged
through water by a moving potential. An extended stationary state fluctuation
theorem is derived. For infinite time, this reduces to the conventional
fluctuation theorem only for small fluctuations; for large fluctuations, it
gives a much larger ratio of the probabilities of the particle to absorb rather
than supply heat. This persists for finite times and should be observable in
experiments similar to a recent one of Wang et al.Comment: 12 pages, 1 eps figure in color (though intelligible in black and
white
Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.
This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability
Exactly Soluble Dynamics of (p,q) String Near Macroscopic Fundamental Strings
We study dynamics of Type IIB bound-state of a Dirichlet string and n
fundamental strings in the background of N fundamental strings. Because of
supergravity potential, the bound-state string is pulled to the background
fundamental strings, whose motion is described by open string rolling radion
field. The string coupling can be made controllably weak and, in the limit , the bound-state energy involved is small
compared to the string scale. We thus propose rolling dynamics of open string
radion in this system as an exactly solvable analog for rolling dynamics of
open string tachyon in decaying D-brane. The dynamics bears a novel feature
that the worldsheet electric field increases monotonically to the critical
value as the bound-state string falls into the background string. Close to the
background string, D string constituent inside the bound-state string decouples
from fundamental string constituents.Comment: 27p, 2 figure
Statistical isotropy of the Cosmic Microwave Background
The breakdown of statistical homogeneity and isotropy of cosmic perturbations
is a generic feature of ultra large scale structure of the cosmos, in
particular, of non trivial cosmic topology. The statistical isotropy (SI) of
the Cosmic Microwave Background temperature fluctuations (CMB anisotropy) is
sensitive to this breakdown on the largest scales comparable to, and even
beyond the cosmic horizon. We propose a set of measures,
() which for non-zero values indicate and quantify statistical
isotropy violations in a CMB map. We numerically compute the predicted
spectra for CMB anisotropy in flat torus universe models.
Characteristic signature of different models in the spectrum are
noted.Comment: Presented at PASCOS'03, January 3-8, 2003, in TIFR, Mumbai; to be
published in a special issue of 'Pramana' (4 pages, 1 figure, style files
included
Preparation and detection of d-wave superfluidity in two-dimensional optical superlattices
We propose a controlled method to create and detect d-wave superfluidity with
ultracold fermionic atoms loaded in two-dimensional optical superlattices. Our
scheme consists in preparing an array of nearest-neighbor coupled square
plaquettes or ``superplaquettes'' and using them as building blocks to
construct a d-wave superfluid state. We describe how to use the coherent
dynamical evolution in such a system to experimentally probe the pairing
mechanism. We also derive the zero temperature phase diagram of the fermions in
a checkerboard lattice (many weakly coupled plaquettes) and show that by tuning
the inter-plaquette tunneling spin-dependently or varying the filling factor
one can drive the system into a d-wave superfluid phase or a Cooper pair
density wave phase. We discuss the use of noise correlation measurements to
experimentally probe these phases.Comment: 8 pages, 6 figure
Wilson Loops in N=2 Super-Yang-Mills from Matrix Model
We compute the expectation value of the circular Wilson loop in N=2
supersymmetric Yang-Mills theory with N_f=2N hypermultiplets. Our results
indicate that the string tension in the dual string theory scales as the
logarithm of the 't Hooft coupling.Comment: 37 pages, 9 figures; v2: Numerical factors corrected, simple
derivation of Wilson loop and discussion of continuation to complex lambda
added; v3: instanton partition function re-analyzed in order to take into
account a contribution of the hypermultiplet
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