1,318 research outputs found
The effect of the handwriting without tears program on student cursive writing achievement at Central Institute for the Deaf (CID)
Handwriting Without Tears (HWT) is a multi-sensory program that provides a simpler approach to the instruction of cursive handwriting. It was administered to a sample of third graders to assess the effectiveness of the program and determine if it would be a viable option for handwriting instruction at CID
Spatial Mixing and Non-local Markov chains
We consider spin systems with nearest-neighbor interactions on an -vertex
-dimensional cube of the integer lattice graph . We study the
effects that exponential decay with distance of spin correlations, specifically
the strong spatial mixing condition (SSM), has on the rate of convergence to
equilibrium distribution of non-local Markov chains. We prove that SSM implies
mixing of a block dynamics whose steps can be implemented
efficiently. We then develop a methodology, consisting of several new
comparison inequalities concerning various block dynamics, that allow us to
extend this result to other non-local dynamics. As a first application of our
method we prove that, if SSM holds, then the relaxation time (i.e., the inverse
spectral gap) of general block dynamics is , where is the number of
blocks. A second application of our technology concerns the Swendsen-Wang
dynamics for the ferromagnetic Ising and Potts models. We show that SSM implies
an bound for the relaxation time. As a by-product of this implication we
observe that the relaxation time of the Swendsen-Wang dynamics in square boxes
of is throughout the subcritical regime of the -state
Potts model, for all . We also prove that for monotone spin systems
SSM implies that the mixing time of systematic scan dynamics is . Systematic scan dynamics are widely employed in practice but have
proved hard to analyze. Our proofs use a variety of techniques for the analysis
of Markov chains including coupling, functional analysis and linear algebra
Assimilation of radar altimeter data in numerical wave models: an impact study in two different wave climate regions
An operational assimilation system incorporating significant wave height observations in high resolution numerical wave models is studied and evaluated. In particular, altimeter satellite data provided by the European Space Agency (ESA-ENVISAT) are assimilated in the wave model WAM which operates in two different wave climate areas: the Mediterranean Sea and the Indian Ocean. The first is a wind-sea dominated area while in the second, swell is the principal part of the sea state, a fact that seriously affects the performance of the assimilation scheme. A detailed study of the different impact is presented and the resulting forecasts are evaluated against available buoy and satellite observations. The corresponding results show a considerable improvement in wave forecasting for the Indian Ocean while in the Mediterranean Sea the assimilation impact is restricted to isolated areas
Nonequilibrium steady states in a vibrated-rod monolayer: tetratic, nematic and smectic correlations
We study experimentally the nonequilibrium phase behaviour of a horizontal
monolayer of macroscopic rods. The motion of the rods in two dimensions is
driven by vibrations in the vertical direction. Aside from the control
variables of packing fraction and aspect ratio that are typically explored in
molecular liquid crystalline systems, due to the macroscopic size of the
particles we are also able to investigate the effect of the precise shape of
the particle on the steady states of this driven system. We find that the shape
plays an important role in determining the nature of the orientational ordering
at high packing fraction. Cylindrical particles show substantial tetratic
correlations over a range of aspect ratios where spherocylinders have
previously been shown by Bates et al (JCP 112, 10034 (2000)) to undergo
transitions between isotropic and nematic phases. Particles that are thinner at
the ends (rolling pins or bails) show nematic ordering over the same range of
aspect ratios, with a well-established nematic phase at large aspect ratio and
a defect-ridden nematic state with large-scale swirling motion at small aspect
ratios. Finally, long-grain, basmati rice, whose geometry is intermediate
between the two shapes above, shows phases with strong indications of smectic
order.Comment: 18 pages and 13 eps figures, references adde
Resected serous cystic neoplasms of the pancreas: Locally aggressive behavior as a predictor of malignant disease? A review of 158 patients with recommendations for treatment.
Background: Serous cystic neoplasms of the pancreas are regarded as a benign entity with rare malignant potential. Surgical resection is generally considered curative. Objective: To perform the largest single institution review of patients who underwent surgical resection for serous cystic neoplasms of the pancreas in the hopes of guiding future management. Methods: Between June 1988 and January 2005, 158 patients with serous cystic neoplasms of the pancreas underwent surgical resection. A retrospective analysis was performed. Univariate and multivariate models were used to determine factors influencing perioperative morbidity and mortality. Major complications were defined as pancreatic fistula or anastomotic leak, postoperative bleed, retained operative material, or death. Minor complications were defined as wound infection, postoperative obstruction/ileus requiring TPN, delayed gastric emptying, arrhythmia, or other infection. Results: The mean age of the patients was 62.1 years, with 75% being female. The majority of patients were symptomatic at presentation (63%), with abdominal pain as the most common symptom. Of the 158 patients, 75 underwent distal pancreatectomy, 65 underwent pancreaticoduodenectomy, 9 underwent central pancreatectomy, 5 underwent local resection or enucleation, and 4 underwent total pancreatectomy. Mean tumor diameter was 5.1 cm. Mean operative time was 277.5 minutes. Mean postoperative length of hospital stay was 11 days. One patient was diagnosed at presentation with serous cystadenocarcinoma. The remaining 157 patients were initially diagnosed with benign serous cystadenoma. One of three patients with locally aggressive benign disease later presented with metastatic disease. Resection margins for all 158 patients were negative for tumor, and only 1 (0.6%) showed lymph node involvement. There was one intraoperative death. The incidence of major perioperative complications was 18%, while the incidence of minor complications was 33%. Men were significantly more likely to experience minor perioperative complications (OR = 3.74, P = .008), while patients greater than 65 years showed a trend toward fewer major complications (OR = 0.36, P = .09). Conclusions: Serous cystic neoplasms of the pancreas which are surgically resected are typically seen in asymptomatic women, as 5 cm neoplasms which are predominantly benign. Most are resected via either a left or right sided pancreatectomy with low mortality risk, but with notable major or minor morbidity. Cystadenocarcinoma is a rare finding on initial resection of serous cystic neoplasms. However, initial pathology specimens exhibiting benign but locally aggressive neoplasia may indicate an increased likelihood of recurrence or metachronous metastasis
Cumulative mutagenesis of the basic residues in the 201-218 region of insulin-like growth factor (IGF)-binding protein-5 results in progressive loss of both IGF-I binding and inhibition of IGF-I biological action
We have reported previously that mutation of two conserved nonbasic amino acids (G203 and Q209) within the highly basic 201–218 region in the C-terminal domain of IGF-binding protein-5 (IGFBP-5) decreases binding to IGFs. This study reveals that cumulative mutagenesis of the 10 basic residues in this region, to create the C-Term series of mutants, ultimately results in a 15-fold decrease in the affinity for IGF-I and a major loss in heparin binding. We examined the ability of mutants to inhibit IGF-mediated survival of MCF-7 cells and were able to demonstrate that this depended not only upon the affinity for IGF-I, but also the kinetics of this interaction, because IGFBP-5 mutants with similar affinity constants (KD) values, but with different association (Ka) and dissociation (Kd) rate values, had markedly different inhibitory properties. In contrast, the affinity for IGF-I provided no predictive value in terms of the ability of these mutants to enhance IGF action when bound to the substratum. Instead, these C-Term mutants appeared to enhance the actions of IGF-I by a combination of increased dissociation of IGF-IGFBP complexes from the substratum, together with dissociation of IGF-I from IGFBP-5 bound to the substratum. These effects of the IGFBPs were dependent upon binding to IGF-I, because a non-IGF binding mutant (N-Term) was unable to inhibit or enhance the actions of IGF-I. These results emphasize the importance of the kinetics of association/dissociation in determining the enhancing or inhibiting effects of IGFBP-5 and demonstrate the ability to generate an IGFBP-5 mutant with exclusively IGF-enhancing activity
Aurora-A Mitotic Kinase Induces Endocrine Resistance through Down-Regulation of ERα Expression in Initially ERα+ Breast Cancer Cells
Development of endocrine resistance during tumor progression represents a major challenge in the management of estrogen receptor alpha (ERα) positive breast tumors and is an area under intense investigation. Although the underlying mechanisms are still poorly understood, many studies point towards the ‘cross-talk’ between ERα and MAPK signaling pathways as a key oncogenic axis responsible for the development of estrogen-independent growth of breast cancer cells that are initially ERα+ and hormone sensitive. In this study we employed a metastatic breast cancer xenograft model harboring constitutive activation of Raf-1 oncogenic signaling to investigate the mechanistic linkage between aberrant MAPK activity and development of endocrine resistance through abrogation of the ERα signaling axis. We demonstrate for the first time the causal role of the Aurora-A mitotic kinase in the development of endocrine resistance through activation of SMAD5 nuclear signaling and down-regulation of ERα expression in initially ERα+ breast cancer cells. This contribution is highly significant for the treatment of endocrine refractory breast carcinomas, because it may lead to the development of novel molecular therapies targeting the Aurora-A/SMAD5 oncogenic axis. We postulate such therapy to result in the selective eradication of endocrine resistant ERαlow/− cancer cells from the bulk tumor with consequent benefits for breast cancer patients
Coarse-grained reconfigurable array architectures
Coarse-Grained Reconfigurable Array (CGRA) architectures accelerate the same inner loops that benefit from the high ILP support in VLIW architectures. By executing non-loop code on other cores, however, CGRAs can focus on such loops to execute them more efficiently. This chapter discusses the basic principles of CGRAs, and the wide range of design options available to a CGRA designer, covering a large number of existing CGRA designs. The impact of different options on flexibility, performance, and power-efficiency is discussed, as well as the need for compiler support. The ADRES CGRA design template is studied in more detail as a use case to illustrate the need for design space exploration, for compiler support and for the manual fine-tuning of source code
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