980 research outputs found
Confirmatory factor analysis and invariance testing between Blacks and Whites of the Multidimensional Health Locus of Control scale.
The factor structure of the Multidimensional Health Locus of Control scale remains in question. Additionally, research on health belief differences between Black and White respondents suggests that the Multidimensional Health Locus of Control scale may not be invariant. We reviewed the literature regarding the latent variable structure of the Multidimensional Health Locus of Control scale, used confirmatory factor analysis to confirm the three-factor structure of the Multidimensional Health Locus of Control, and analyzed between-group differences in the Multidimensional Health Locus of Control structure and means across Black and White respondents. Our results indicate differences in means and structure, indicating more research is needed to inform decisions regarding whether and how to deploy the Multidimensional Health Locus of Control appropriately
Forestry on the Island of Taiwan, ROC - The State of the Art
The forests of Taiwan vary from lush subtropical vegetation to subalpine coniferous associations. Topography is exceedingly rugged, and stands border on the verge of silvicultural inoperability. In the 1950s and 1960s, the wood products industry in the Republic of China was of paramount importance; the production of high-quality sawtimber from old-growth cypress (Cupressaceae) stands provided the financial capital that built one of the most prosperous national economies in the modern world. In the 1980s, forestry in Taiwan is a curious blend of old methods and new technologies, as modern silvicultural practices are used to reforest cutover cypress stands, to harvest and reproduce remaining old-growth stands, and to expand the silvicultural importance of other forest types on the island. Many applied research efforts would be promising in application to the forests of Taiwan, such as long-term studies of silvicultural practices on water quality, methodology of natural regeneration applied to cypress and Taiwania cryptomerioides (Taxodiaceae), uneven-aged regulation applied to bamboo, Phyllostachys pubescens (Bambusaceae), growth and yield in coniferous plantations, effectiveness of modern herbicides in controlling competition in young plantations, and application of contemporary economic assessments in the evaluation of silvicultural alternatives
High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy
Time-domain THz transmission experiment was performed on a film deposited on sapphire substrate. Temperatures between 300
and 923 K were investigated and complex permittivity spectra of the film were
determined. The lowest frequency optic phonon near 28 cm reveals a slow
monotonic decrease in frequency on heating with no significant anomaly near the
phase transitions. We show that the dielectric anomaly near the ferroelectric
phase transition can be explained by slowing down of a relaxational mode,
observed in the THz spectra. A second harmonic generation signal observed in a
single crystal confirms a loss of center of symmetry in the ferroelectric phase
and a presence of polar clusters in the intermediate ferroelastic phase.Comment: subm. to J. Phys.: Condens. Matte
Large-scale analysis of neurite growth dynamics on micropatterned substrates
2011 September 15During both development and regeneration of the nervous system, neurons display complex growth dynamics, and several neurites compete to become the neuron's single axon. Numerous mathematical and biophysical models have been proposed to explain this competition, which remain experimentally unverified. Large-scale, precise, and repeatable measurements of neurite dynamics have been difficult to perform, since neurons have varying numbers of neurites, which themselves have complex morphologies. To overcome these challenges using a minimal number of primary neurons, we generated repeatable neuronal morphologies on a large scale using laser-patterned micron-wide stripes of adhesive proteins on an otherwise highly non-adherent substrate. By analyzing thousands of quantitative time-lapse measurements of highly reproducible neurite growth dynamics, we show that total neurite growth accelerates until neurons polarize, that immature neurites compete even at very short lengths, and that neuronal polarity exhibits a distinct transition as neurites grow. Proposed neurite growth models agree only partially with our experimental observations. We further show that simple yet specific modifications can significantly improve these models, but still do not fully predict the complex neurite growth behavior. Our high-content analysis puts significant and nontrivial constraints on possible mechanistic models of neurite growth and specification. The methodology presented here could also be employed in large-scale chemical and target-based screens on a variety of complex and subtle phenotypes for therapeutic discoveries using minimal numbers of primary neurons.United States. Dept. of Defense. (National Defense Science and Engineering Graduate Fellowship
Constitutive cytoplasmic localization of p21Waf1/Cip1 affects the apoptotic process in monocytic leukaemia
In the present study, we analysed the expression and localization of p21Waf1/Cip1 in normal and malignant haematopoietic cells. We demonstrate that in normal monocytic cells, protein kinase C (PKC)-induced p21 gene activation, which is nuclear factor-κB (NF-κB) independent, results in predominantly cytoplasmic localized p21 protein. In acute monocytic leukaemia (M4, M5), monocytic blasts (N=12) show constitutive cytoplasmic p21 expression in 75% of the cases, while in myeloid leukaemic blasts (N=10), low nuclear and cytoplasmic localization of p21 could be detected, which is also PKC dependent. Constitutive p21 expression in monocytic leukaemia might have important antiapoptotic functions. This is supported by the finding that in U937 cells overexpressing p21, VP16-induced apoptosis is significantly reduced (20.0±0.9 vs 55.8±3.8%, P<0.01, N=5), reflected by a reduced phosphorylation of p38 and JNK. Similarly, AML blasts with high cytoplasmic p21 were less sensitive to VP16-induced apoptosis as compared to AML cases with low or undetectable p21 expression (42.25 vs 12.3%, P<0.01). Moreover, complex formation between p21 and ASK1 could be demonstrated in AML cells, by means of coimmunoprecipitation. In summary, these results indicate that p21 has an antiapoptotic role in monocytic leukaemia, and that p21 expression is regulated in a PKC-dependent and NF-κB independent manner.
The non-coding landscape of head and neck squamous cell carcinoma.
Head and neck squamous cell carcinoma (HNSCC) is an aggressive disease marked by frequent recurrence and metastasis and stagnant survival rates. To enhance molecular knowledge of HNSCC and define a non-coding RNA (ncRNA) landscape of the disease, we profiled the transcriptome-wide dysregulation of long non-coding RNA (lncRNA), microRNA (miRNA), and PIWI-interacting RNA (piRNA) using RNA-sequencing data from 422 HNSCC patients in The Cancer Genome Atlas (TCGA). 307 non-coding transcripts differentially expressed in HNSCC were significantly correlated with patient survival, and associated with mutations in TP53, CDKN2A, CASP8, PRDM9, and FBXW7 and copy number variations in chromosomes 3, 5, 7, and 18. We also observed widespread ncRNA correlation to concurrent TP53 and chromosome 3p loss, a compelling predictor of poor prognosis in HNSCCs. Three selected ncRNAs were additionally associated with tumor stage, HPV status, and other clinical characteristics, and modulation of their expression in vitro reveals differential regulation of genes involved in epithelial-mesenchymal transition and apoptotic response. This comprehensive characterization of the HNSCC non-coding transcriptome introduces new layers of understanding for the disease, and nominates a novel panel of transcripts with potential utility as prognostic markers or therapeutic targets
Unraveling Diffusion in Fusion Plasma: A Case Study of In Situ Processing and Particle Sorting
This work starts an in situ processing capability to study a certain
diffusion process in magnetic confinement fusion. This diffusion process
involves plasma particles that are likely to escape confinement. Such particles
carry a significant amount of energy from the burning plasma inside the tokamak
to the diverter and damaging the diverter plate. This study requires in situ
processing because of the fast changing nature of the particle diffusion
process. However, the in situ processing approach is challenging because the
amount of data to be retained for the diffusion calculations increases over
time, unlike in other in situ processing cases where the amount of data to be
processed is constant over time. Here we report our preliminary efforts to
control the memory usage while ensuring the necessary analysis tasks are
completed in a timely manner. Compared with an earlier naive attempt to
directly computing the same diffusion displacements in the simulation code,
this in situ version reduces the memory usage from particle information by
nearly 60% and computation time by about 20%
The classical limit for a class of quantum baker's maps
We show that the class of quantum baker's maps defined by Schack and Caves
have the proper classical limit provided the number of momentum bits approaches
infinity. This is done by deriving a semi-classical approximation to the
coherent-state propagator.Comment: 18 pages, 5 figure
Interpreting palaeofire evidence from fluvial sediments:a case study from Santa Rosa Island, California, with implications for the Younger Dryas Impact Hypothesis
International audienceFluvial sequences from the late Pleistocene to the Holocene are exposed in Arlington Canyon, Santa Rosa Island, Northern Channel Islands, California, USA, including one outcrop that features centrally in the controversial hypothesis of an extra-terrestrial impact at the onset of the Younger Dryas. The fluvial sequence in Arlington Canyon contains a significant quantity and range of organic material, much of which has been charred. The purpose of this study was to systematically describe the key outcrop of the Arlington sequence, provide new radiocarbon age control and analyse organic material in the Arlington sediments within a rigorous palaeobotanical and palaeo-charcoal context. These analyses provide a test of previous claims for catastrophic impact-induced fire in Arlington Canyon. Carbonaceous spherular materials were identified as predominantly fungal sclerotia; ‘carbon elongates’ are predominantly arthropod coprolites, including termite frass. ‘Glassy carbon’ formed from the precipitation of tars during charcoalification. None of these materials indicate high-temperature formation or combustion. Charcoal and other materials in Arlington Canyon document widespread and frequent fires both before and after the onset of the Younger Dryas, recording predominantly low-temperature surface fires. In summary, we find no evidence in Arlington Canyon for an extra-terrestrial impact or catastrophic impact-induced fire
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