Influence of surrounding media refractive index on the thermal and strain sensitivities of long-period gratings

A detailed study of the thermal and strain sensitivities of a long-period grating when the device is immersed in different external media is presented. The range of refractive indices analyzed are within 1.000 to 1.447, corresponding to samples of air, water, ethanol, naphtha, thinner, turpentine, and kerosene. Within the same range of refractive indices, the strain sensitivity is between (-0.24 +/- 0.03) and (-0.94 +/- 0.11) pm/microepsilon. For the grating immersed in these fluids, the refractive index sensitivity ranges from -3 to -1035.6 nm per refractive index units. The coupling thermo-optic coefficients and the strain-optic coefficients are also measured, resulting in the range from (2.45 +/- 0.04)x10(-5) to (15.89 +/- 0.82)x10(-5) deg C(-1) and (-1.15 +/- 0.04) to (-1.61 +/- 0.04) microepsilon(-1), respectively. A noticeable nonlinear behavior of the thermal sensitivity is found for external media with refractive indices higher than 1.430.     

Tailoring fiber grating sensors for assessment of highly refractive fuels

Three approaches that allow the tailoring of long period gratings based refractometric sensors for concentration measurement in fuel blends are employed to assess the fuel quality in biodiesel and biodiesel-petrodiesel blend. To allow the analysis of fuel samples with refractive index higher than fiber cladding one, the samples refractive indices were changed by thermo-optic effect and by dilution in a standard substance with low refractive index. The obtained results show the sensor can detect oil concentration in biodiesel samples with resolution as better as 0.07% and biodiesel concentration in biodiesel-petrodiesel samples with average resolution of 0.09%.     

Investigation on the Wear Properties of Primary Si Modified Al–20Si Alloy

In the present study, Al?C20Si alloy has been modified by Cu?C13P master alloy to obtain Al?C20Si?C0.1P alloy. The wear properties of Al?C20Si?C0.1P alloy have been investigated and compared with that of Al?C20Si alloy. The microstructure of Al?C20Si?C0.1P alloy consisted of primary and eutectic silicon distributed in the Al matrix. The size of primary Si is much smaller than that observed in Al?C20Si alloy. Wear tests have been conducted over a wide range of loads and sliding velocities. It has been observed that the wear rates of Al?C20Si?C0.1P alloy are lower than that of Al?C20Si alloy. The coefficient of friction is more or less constant in both the alloys but is low in Al?C20Si?C0.1P alloy. The better wear resistance of Al?C20Si?C0.1P alloy is discussed in the light of its modified microstructure evolved during solidification.     

Hydroxyurea accelerates the loss of epidermal growth factor receptor genes amplified as double-minute chromosomes in human glioblastoma multiforme

OBJECTIVE: We sought to determine whether hydroxyurea could accelerate the loss of amplified epidermal growth factor receptor (EGFR) genes from glioblastoma multiforme (GBM). There is good reason to think that elimination of amplified EGFR genes from GBMs will negatively impact tumor growth. Hydroxyurea has previously been shown to induce the loss of amplified genes from extrachromosomal double minutes (dmin) but not from chromosomal homogeneously staining regions. METHODS: Pulsed-field gel electrophoresis and Southern blot hybridization were used to demonstrate EGFR genes amplified as dmin. Giemsa-stained metaphase spreads were prepared in an attempt to visualize dmin. A GBM cell line containing amplified EGFR genes was treated continuously in vitro with 0 to 150 mumol/L hydroxyurea, and slot blot analysis was used to show the loss of amplified EGFR genes. RESULTS: Amplified EGFR genes were found on dmin in 4 of 11 (36%) fresh human GBM biopsy specimens. None of the GBMs contained EGFR genes amplified as homogeneously staining regions. Amplified dmin were not microscopically visible when stained with Giemsa because of their small size. Slot blot analysis showed that these low doses of hydroxyurea accelerated the loss of amplified EGFR genes in a dose- and time-dependent fashion. Pulsed-field gel electrophoresis and Southern blot analysis confirmed that EGFR gene loss was accompanied by amplified dmin loss in a dose-dependent fashion. CONCLUSION: These studies suggest the potential use of low-dose hydroxyurea in the treatment of GBMs.     

Is It Prudent to Administer All Items for Each Child Behavior Checklist Cross-Informant Syndrome? Evaluating the Psychometric Properties of the Youth Self-Report Dimensions With Confirmatory Factor Analysis and Item Response Theory.

Through surveying of children in 10 nations with parent, teacher, and Youth Self-Report (YSR) forms of the Child Behavior Checklist (CBCL), cross-informant syndromes (CISs) were derived and cross-validated by sample-dependent methodology. Generalizing CBCL syndromes and norms to nations excluded from its normative sample is problematic. This study used confirmatory factor analyses (CFAs) to test factor model fit for CISs on the YSR responses of 625 Jamaican children ages 11 to 18 years. Item response theory (IRT), a sample independent methodology, was used to estimate the psychometric properties of individual items on each dimension. CFAs indicated poor to moderate model-to-data fit. Across all syndromes, IRT analyses revealed that more than 3/4 of the cross-informant items yielded little information. Eliminating such items could be cost effective in terms of administration time yet improve the measure's discrimination across syndrome severity levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Markovian and cellular automata land-use change predictive model of the Usangu Catchment

Usangu Catchment, in Tanzania, is vital for its rice production in which more than 30% of Tanzanian rice is grown. The catchment is a part of the Southern Agricultural Corridor of Tanzania where major agricultural intensification is expected to take place. Given the role of this catchment, it is important to investigate the effect of agricultural intensification, land-use/land-cover (LULC) change and climate variability on water balance in the catchment. Thus, the objective of the study was to simulate Usangu Catchment’s LULC of 2020 based on LULC of 2000, 2006 and 2013 using Markov Chain and Cellular Automata Analysis.Social, edaphic, climatic and landscape geomorphology factors governing the LULC change and distribution were used to prepare LULC suitability maps in geographical information system.The relative importance of LULC change factors was determined using the analytic hierarchy process and aggregated using weighted linear combination under multi-criteria evaluation approach. The model was validated using simulated and observed LULC 2013. The standard kappa coefficient (κ-standard) and overall agreements of the model were 0.6776 and 0.9125, respectively. The error due to quantity is 0.0243 while error due to allocation is 0.0667. The simulated LULC 2020 scenario shows the increase in urban area by 8.2% and a major decrease in forestland and shrubs by 20.6% and 6.9%, respectively. About 19.6% grassland and 8.5% of agricultural land in 2013 will be converted to urban land by 2020. On the other hand, about 372.0 km² (10.4%) of wetlands and 368.2 km² (10.3%) of woodlands will be converted to agricultural land. The 2020 LULC simulation model of Usangu developed in this study provide some useful information for future LULC scenarios and data for water balance models and preparation of future ecological conservation plans.     

Jamaican and American adult perspectives on child psychopathology: Further exploration of the threshold model.

Although several factors determine whether children receive psychological intervention, cultural determinants may be particularly influential. Cultural factors may influence adults' levels of concern over child psychopathology. This possibility was explored by comparing adult attitudes in 2 socioculturally different societies. Jamaican and American parents, teachers, and clinicians (total N?=?382) judged vignettes of 2 children, 1 with overcontrolled (e.g., fearfulness) and 1 with undercontrolled (e.g., fighting) problems. Regression analyses revealed that although years of education affected some adult ratings, culture had the most profound effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)