Apparent Features Research Articles

Using students’ drawings to elicit general and special educators’ perceptions of co-teaching

This paper describes the findings of a study of general and special educators’ perceptions of co-teaching in elementary and middle school classrooms. A total of 85 students, 20 general education, and 11 special education teachers participated in this investigation in which student drawings were used as both data and as tools to spark teacher reflection. Students’ pictorial depictions of co-teaching were analyzed for apparent features and traits. Co-teachers’ reactions to the drawings were springboards for reflective conversations around modifications they felt needed to take place to improve co-teaching. Findings suggest that proactive role distribution, support structures, and trust building are critical factors in strengthening co-teaching. Implications for practice are discussed.

Constitutional Duplication of a Region of Chromosome Yp Encoding AMELY, PRKY, and TBL1Y: Implications for Sex Chromosome Analysis and Bone Marrow Engraftment Analysis

Amelogenin has chromosome X (AMELX) and Y (AMELY) homologs that can be differentiated based on the length of polymerase chain reaction (PCR) amplification products. In addition to being useful for gender identification, analysis of amelogenin has utility for monitoring bone marrow engraftment in patients after a sex-mismatched bone marrow transplant, characterizing sex chromosome abnormalities, and for forensic purposes for analyzing mixtures of male and female DNA. Here, we describe two brothers in which PCR analysis demonstrated twofold greater AMELY products compared with AMELX products. Karyotype and X/Y fluorescence in situ hybridization analysis demonstrated a single copy of the X and Y chromosomes without any identifiable abnormalities. Oligonucleotide comparative genomic hybridization array analysis demonstrated a duplication of a portion of chromosome Yp that encompassed a region of at least 2.6 Mb but not greater than 4.0 Mb. The amplified region contains the genes AMELY, transducin (beta)-like 1 protein Y (TBL1Y), and protein kinase Y (PRKY). To our knowledge, duplication of this region has not previously been reported. The family history is unremarkable, and the brothers are without ap-parent dysmorphic features. Although this and other genetic variants involving AMELY are uncommon, one should use caution when using amelogenin for sex chromosome analysis and bone marrow engraftment analysis.

Geology and petroleum potential of the Fairway Basin in the Tasman Sea

The Fairway Basin is a large, generally north – south-trending, sediment-filled structure in water 1500 – 3000 m deep, on the eastern slope of the Lord Howe Rise in the Tasman Sea, and is partly within Australian jurisdiction. It was poorly known until a few years ago, when seismic profiling and piston coring cruises were carried out. The basin, about 1100 km long and 120 – 200 km wide, can be divided into three segments—north, central and south—that trend northwest, north and north-northwest, respectively. All three segments probably formed by thinning of continental crust during breakup of Lord Howe Rise and surrounding aseismic continental ridges in the Late Cretaceous and Paleocene. Normal faulting, large inputs of terrigenous sediment and subsidence to bathyal marine depths occurred during that time. A period of compression, perhaps related to overthrusting on New Caledonia, occurred in the Eocene, leading to uplift (and in parts, erosion) of northern Lord Howe Rise, and reversal of faulting in the basin. By the Oligocene, the area was again in bathyal depths, and pelagic ooze and some turbidites accumulated. The basinal sequence is generally 2000 – 4000 m thick, with 1200 – 3200 m of Cretaceous to Eocene sediment concentrated in depocentres, capped by 500 – 800 m of Oligocene and younger sediment. In the depocentres, numerous sedimentary diapirs pierce sedimentary sequences. The sedimentary diapirs appear to be fed by Cretaceous muds deposited during rifting. Often, these diapirs are overlain by faults extending to the seafloor, and hummocky bathymetry is possibly caused by fluid escape. The overall geology suggests that the Fairway Basin may be a large frontier hydrocarbon province. Seismic profiles display a bottom-simulating reflector above many depocentres, 500 – 700 m below the seafloor. The bottom-simulating reflector has positive polarity, which could result from a diagenetic phase transformation, a thin gas hydrate layer with a sharp top, or from the sharp base of a gas layer (probably beneath gas hydrates). Standard piston cores taken above diapirs and apparent fluid-escape features have recovered little gas. Other than drilling, the next steps in assessing petroleum potential are to clearly document fluid-escape structures, and to sample any fluids emitted for hydrocarbons.

Electronic Excited States of Polynucleotides: A Study by Electroabsorption Spectroscopy

Electroabsorption spectra were obtained for single-stranded polynucleotides poly(U), poly(C), poly(A), and poly(G) in glycerol/water glass at low temperature, and the differences in permanent dipole moment (Deltamu) and polarizability (Deltaalpha) were estimated for several spectral ranges covering the lowest energy absorption band around 260 nm. In each spectral range, the electrooptical parameters associated with apparent features in the absorption spectrum exhibit distinct values representing either a dominant single transition or the resultant value for a group of a relatively narrow cluster of overlapping transitions. The estimated spacing in energy between electronic origins of these transitions is larger than the electronic coupling within the Coulombic interaction model which is usually adopted in computational studies. The electroabsorption data allow us to distinguish a weak electronic transition associated with a wing in polynucleotide absorption spectra, at an energy below the electronic origin in absorption spectra of monomeric nucleobases. In poly(C) and poly(G), these low-energy transitions are related to increased values of Deltamu and Deltaalpha, possibly indicating a weak involvement of charge resonance in the respective excited states. A model capable of explaining the origin of low-energy excited states, based on the interaction of pipi* and npi* transitions in neighboring bases, is introduced and briefly discussed on the grounds of point dipole interaction.

Electrical properties of Titan's surface from Cassini RADAR scatterometer measurements

We report regional-scale low-resolution backscatter images of Titan's surface acquired by the Cassini RADAR scatterometer at a wavelength of 2.18-cm. We find that the average angular dependence of the backscatter from large regions and from specific surface features is consistent with a model composed of a quasi-specular Hagfors term plus a diffuse cosine component. A Gaussian quasi-specular term also fits the data, but less well than the Hagfors term. We derive values for the mean dielectric constant and root-mean-square (rms) slope of the surface from the quasi-specular term, which we ascribe to scattering from the surface interface only. The diffuse term accommodates contributions from volume scattering, multiple scattering, or wavelength-scale near-surface structure. The Hagfors model results imply a surface with regional mean dielectric constants between 1.9 and 3.6 and regional surface roughness that varies between 5.3° and 13.4° in rms-slope. Dielectric constants between 2 and 3 are expected for a surface composed of solid simple hydrocarbons, water ice, or a mixture of both. Smaller dielectric constants, between 1.6 and 1.9, are consistent with liquid hydrocarbons, while larger dielectric constants, near 4.5, may indicate the presence of water–ammonia ice [Lorenz, R.D., 1998. Icarus 136, 344–348] or organic heteropolymers [Thompson, W.R., Squyres, S.W., 1990. Icarus 86, 336–354]. We present backscatter images corrected for angular effects using the model residuals, which show strong features that correspond roughly to those in 0.94-μm ISS images. We model the localized backscatter from specific features to estimate dielectric constant and rms slope when the angular coverage is within the quasi-specular part of the backscatter curve. Only two apparent surface features are scanned with angular coverage sufficient for accurate modeling. Data from the bright albedo feature Quivira suggests a dielectric constant near 2.8 and rms slope near 10.1°. The dark albedo feature Shangri-La is best fit by a Hagfors model with a dielectric constant close to 2.4 and an rms slope near 9.5°. From the modeled backscatter curves, we find the average radar albedo in the same linear (SL) polarization to be near 0.34. We constrain the total-power albedo in order to compare the measurements with available groundbased radar results, which are typically obtained in both senses of circular polarization. We estimate an upper limit of 0.4 on the total-power albedo, a value that is significantly higher than the 0.21 total albedo value measured at 13 cm [Campbell, D., Black, G., Carter, L., Ostro, S., 2003. Science 302, 431–434]. This is consistent with a surface that has more small-scale structure and is thus more reflective at 2-cm than 13-cm. We compare results across overlapping observations and observe that the reduction and analysis are repeatable and consistent. We also confirm the strong correlations between radar and near-infrared images.

Demographic features of old people in Belgrade

The process of demographic ageing is one of the most apparent features of the demographic development of Serbia. The increase of the percentage of aged population is also present in Belgrade, although Belgrade itself, being the center of immigration and the major urban agglomeration, has a specific population development. This paper analyzes the dynamics and demographic features of the citizens of Belgrade older than 60, in the period between 1981 and 2000. It discusses the changes in gender and age distribution of this population group, as well as the processes of ageing and feminization of the elders. It also indicates related differences between the municipalities of Belgrade, as well as between the City of Belgrade, the Settlement of Belgrade and the settlements of Belgrade outside the inner urban zone.

The water extract of Omija protects H9c2 cardiomyoblast cells from hydrogen peroxide through prevention of mitochondrial dysfunction and activation of caspases pathway

The water extract of Omija (Omija) has been used traditionally in the treatment of ischemic damage of the heart and brain tissues. However, little is known about the mechanism by which it rescues myocardial cells from oxidative stress. This study was designed to investigate the protective mechanisms of Omija on H(2)O(2)-induced cytotoxicity in H9c2 cardiomyoblast cells. Treatment with H(2)O(2) resulted in the death of H9c2 cells, characterized by apparent apoptotic features, including fragmentation of the nucleus and an increase in the sub-G(0)/G(1) fraction of the cell cycle. However, Omija markedly suppressed the apoptotic characteristics of H9c2 cells induced by H(2)O(2). In addition, Omija suppressed the features of mitochondrial dysfunction, including changes in the mitochondrial membrane potential and cytosolic release of cytochrome c in H(2)O(2)-treated cells. Treatment with Omija further inhibited the catalytic activation of caspase-9 and caspase-3 and induction of Fas by H(2)O(2). Taken together, these data indicate that the water extract of Omija protects H9c2 cardiomyoblast cells from oxidative stress of H(2)O(2) through inhibition of mitochondrial dysfunction and activation of intrinsic caspase cascades, including caspase-3 and caspase-9.

Namibia: Consensus institutions and majoritarian politics

This article assesses the utility of Arend Lijphart's classification scheme of democracies by means of a case study of Namibia. In particular, the article examines whether Namibia represents a case of consensus democracy, based on institutional criteria within the power-sharing and power-division dimensions, as developed in Lijphart's Patterns of Democracy (1999). The application of the ten criteria results in a mixed outcome, with an overall modal value of ‘moderately consensus’, a modal value of strongly majoritarian for the executive-parties dimension, and moderately consensus for the federal-executive dimension. The highly varied scores for each of the criteria, particularly within the first of Lijphart's two dimensions, present several problems. It is argued that the statistical modal value represents a distorted image of Namibian politics. Namibia scores consistently on the majoritarian side for criteria which conceptually concern the essence of the consensus modal. Moreover, apparent consensus features such as tripartite institutions, bicameralism, and a rigid constitution do not ‘behave’ as such due to one-party dominance, and neither does proportional representation produce consensus politics. Lijphart's criteria are too formal, and should not receive equal weight. The article concludes that power-sharing is better investigated by focusing on just two criteria, namely the party system and the strongly related criterion of government coalitions. Moreover, it is essential to examine political behaviour, in particular of governing elites, to look for the presence of cooperation and compromise, paradoxically issues which were more prominent in Lijphart's earlier work.

Acute and subacute toxicity studies of Aegle marmelos Corr., an Indian medicinal plant

This study was designed to elucidate the toxicity of the widely used plant Aegle marmelos in rats. We have taken total alcoholic, total aqueous, whole aqueous and methanolic extracts isolated from the leaves of A. marmelos and studied their toxic effects. Acute, subacute and LD(50) values were determined in experimental rats. The dead animals were obtained from primary screening studies, LD(50) value determination experiments and acute studies subjected to postmortem studies. The external appearance of the dead animals, the appearance of the viscera, heart, lungs, stomach, intestine, liver, kidney, spleen and brain were carefully noted and any apparent and significant features or differences from the norm were recorded. Following the chronic administration of A. marmelos for 14 days, the vital organs such as heart, liver, kidney, testis, spleen and brain were carefully evaluated by histopathological studies and any apparent and significant changes or differences from the norm were studied. From the acute administration of A. marmelos, the LD(50) values were determined using graphical method. The hearts stopped in systolic stand-still in the acute experiments. There were no remarkable changes noticed in the histopathological studies after 50 mg/kg body wt of the extracts of A. marmelos when administered intraperitoneally for 14 days successively. Pathologically, neither gross abnormalities nor histopathological changes were observed. After calculation of LD(50) values using graphical methods, we found a broad therapeutic window and a high therapeutic index value for A. marmelos extracts. Intraperitoneal administration of the extracts of the leaves of A. marmelos at doses of 50, 70, 90 and 100 mg/kg body wt for 14 consecutive days to male and female Wistar rats did not induce any short-term toxicity. Collectively, these data demonstrate that the extracts of the leaves of A. marmelos have a high margin of drug safety.

Presynaptic Unsilencing: Searching for a Mechanism

Nascent synaptic networks have a high incidence of silent synapses. In this issue of Neuron, Shen et al. show that a brief burst of action potentials rapidly awaken silent synapses by increasing the availability of synaptic vesicles for fusion through BDNF-triggered presynaptic actin remodeling mediated by the small GTPase Cdc42.

Dental microwear texture analysis: technical considerations

Dental microwear analysis is commonly used to infer aspects of diet in extinct primates. Conventional methods of microwear analysis have usually been limited to two-dimensional imaging studies using a scanning electron microscope and the identification of apparent individual features. These methods have proved time-consuming and prone to subjectivity and observer error. Here we describe a new methodological approach to microwear: dental microwear texture analysis, based on three-dimensional surface measurements taken using white-light confocal microscopy and scale-sensitive fractal analysis. Surface parameters for complexity, scale of maximum complexity, anisotropy, heterogeneity, and textural fill volume offer repeatable, quantitative characterizations of three-dimensional surfaces, free of observer measurement error. Some results are presented to illustrate how these parameters distinguish extant primates with different diets. In this case, microwear surfaces of Cebus apella and Lophocebus albigena, which consume some harder food items, have higher average values for complexity than do folivores or soft fruit eaters.

Regime shifts and red noise in the North Pacific

Regimes and regime shifts are important concepts for understanding decadal variability in the physical system of the North Pacific because of the potential for an ecosystem to reorganize itself in response to such shifts. There are two prevalent senses in which these concepts are taken in the literature. The first is a formal definition and posits multiple stable states and rapid transitions between these states. The second is more data-oriented and identifies local regimes based on differing average climatic levels over a multi-annual duration, i.e. simply interdecadal fluctuations. This second definition is consistent with realizations from stochastic red noise processes to a degree that depends upon the particular model. Even in 100 year long records for the North Pacific a definition of regimes based solely on distinct multiple stable states is difficult to prove or disprove, while on interdecadal scales there are apparent local step-like features and multi-year intervals where the state remains consistently above or below the long-term mean. The terminologies climatic regime shift, statistical regime shift or climatic event are useful for distinguishing this second definition from the first. To illustrate the difficulty of advocating one definition over the other based upon a relatively short time series, we compare three simple models for the Pacific Decadal Oscillation (PDO). The 104-year PDO record is insufficient to statistically distinguish a single preference between a square wave oscillator consistent with the formal definition for regime shifts, and two red noise models that are compatible with climatic regime shifts. Because of the inability to distinguish between underlying processes based upon data, it is necessary to entertain multiple models and to consider how each model would impact resource management. In particular the persistence in the fitted models implies that certain probabilistic statements can be made regarding climatic regime shifts, but we caution against extrapolation to future states based on curve fitting techniques.

Grading of Yarn Appearance Using Image Analysis and an Artificial Intelligence Technique

In this research, a new method is used for grading of yarn appearance based on yarn images of ASTM standard (section D 2255), by using an image processing technique and an artificial intelligence technique. In this method, grading of yarn appearance is based on computer vision and analyzing the images of standard pictorial boards of yarn. Therefore this method is very similar to human vision. The logic of the classification by ASTM is considered and then a new definition for classification of yarn appearance grade is presented. In this method of classification, the grading procedure is not dependent on yarn structure and raw materials. Thus it is possible to use this method for grading of any type of yarn based on apparent features.

Chelatases: distort to select?

Chelatases catalyze the insertion of a specific metal ion into porphyrins, a key step in the synthesis of metalated tetrapyrroles that are essential for many cellular processes. Despite apparent common structural features among chelatases, no general reaction mechanism accounting for metal ion specificity has been established. We propose that chelatase-induced distortion of the porphyrin substrate not only enhances the reaction rate by decreasing the activation energy of the reaction but also modulates which divalent metal ion is incorporated into the porphyrin ring. We evaluate the recently recognized interaction between ferrochelatase and frataxin as a way to regulate iron delivery to ferrochelatase, and thus iron and heme metabolism. We postulate that the ferrochelatase-frataxin interaction controls the type of metal ion that is delivered to ferrochelatase.

Diffusion of gallium in sapphire

In this paper, the characteristics of the diffusion of gallium into sapphire are investigated by SIMS analysis, as a step towards the fabrication of optimized Ga:sapphire optical waveguides. The diffusion coefficient was obtained for temperatures between 1400 °C and 1600 °C, and the results confirm that sapphire substrates can be readily doped with gallium, to depths in the order of microns, at a temperature of 1600 °C. The procedure yields samples with low surface roughness and no apparent unwanted surface features, and the dopant concentration can be selected over a wide range, as gallium has a high solid solubility in sapphire.

Development of Appearance Grading Method of Cotton Yarns for Various Types of Yarns

In this research, a new method is developed for grading various types of yarn for appearance using image analysis and an artificial neural network. The images of standard yarn boards were analyzed by image analysis and four different faults factors were defined and measured for each series of yarn counts. For each series of yarn counts, a neural network with one layer was trained by measured fault factors of standard boards. The trained neural networks were used for grading various types of yarns. The yarns were also graded by the conventional standard method. The results of grading various types of yarns by image analysis and conventional standard method are compared. We found a strong correlation between the results of grading by two methods. Whereas, in the image analysis method, the grading procedure is not dependent on yarn structure and raw materials, we concluded that it is possible to use this method for grading of any types of yarns based on their apparent features.

Optical-geometrical effects on the photoluminescence spectra of Si nanocrystals embedded in SiO2

We demonstrate that thickness, optical constants, and details of the multilayer stack, together with the detection setting, strongly influence the photoluminescence spectra of Si nanocrystals embedded in SiO2. Due to multiple reflections of the visible light against the opaque silicon substrate, an interference pattern is built inside the oxide layer, which is responsible for the modifications in the measured spectra. This interference effect is complicated by the depth dependence of (i) the intensity of the excitation laser and (ii) the concentration of the emitting nanocrystals. These variations can give rise to apparent features in the recorded spectra, such as peak shifts, satellite shoulders, and even splittings, which can be mistaken as intrinsic material features. Thus, they can give rise to an erroneous attribution of optical bands or estimate of the average particle size, while they are only optical-geometrical artifacts. We have analyzed these effects as a function of material composition (Si excess fraction) and thickness, and also evaluated how the geometry of the detection setup affects the measurements. To correct the experimental photoluminescence spectra and extract the true spectral shape of the emission from Si nanocrystals, we have developed an algorithm based on a modulation function, which depends on both the multilayer sequence and the experimental configuration. This procedure can be easily extended to other heterogeneous systems.

Long-term changes and variability in a transient simulation with a chemistry-climate model employing realistic forcing

Abstract. A transient simulation with the interactively coupled chemistry-climate model (CCM) E39/C has been carried out which covers the 40-year period between 1960 and 1999. Forcing of natural and anthropogenic origin is prescribed where the characteristics are sufficiently well known and the typical timescales are slow compared to synoptic timescale so that the simulated atmospheric chemistry and climate evolve under a "slowly" varying external forcing. Based on observations, sea surface temperature (SST) and ice cover are prescribed. The increase of greenhouse gas and chlorofluorocarbon concentrations, as well as nitrogen oxide emissions are taken into account. The 11-year solar cycle is considered in the calculation of heating rates and photolysis of chemical species. The three major volcanic eruptions during that time (Agung, 1963; El Chichon, 1982; Pinatubo, 1991) are considered. The quasi-biennial oscillation (QBO) is forced by linear relaxation, also known as nudging, of the equatorial zonal wind in the lower stratosphere towards observed zonal wind profiles. Beyond a reasonable reproduction of mean parameters and long-term variability characteristics there are many apparent features of episodic similarities between simulation and observation: In the years 1986 and 1988 the Antarctic ozone holes are smaller than in the other years of that decade. In mid-latitudes of the Southern Hemisphere ozone anomalies resemble the corresponding observations, especially in 1985, 1989, 1991/1992, and 1996. In the Northern Hemisphere, the episode between the late 1980s and the first half of the 1990s is dynamically quiet, in particular, no stratospheric warming is found between 1988 and 1993. As observed, volcanic eruptions strongly influence dynamics and chemistry, though only for few years. Obviously, planetary wave activity is strongly driven by the prescribed SST and modulated by the QBO. Preliminary evidence of realistic cause and effect relationships strongly suggests that detailed process-oriented studies will be a worthwhile endeavour.

Protective effects of icariin on human umbilical vein endothelial cell injury induced by H 2O 2 in vitro

Icariin is a flavonoid isolated from Epimedium and is considered to be the major pharmacological active component of Epimedii Herba. In the present investigation, we studied and confirmed the protective activity of icariin on H 2O 2-induced injury in human umbilical vein endothelial cell line: ECV-304. Eighteen-hour treatment with 750 μmol l −1 H 2O 2 significantly decreased the viability of ECV-304 cells, which was accompanied with apparent apoptotic features, including distinct cell morphological alteration and the increase of caspase-3 expression. In addition, it is observed that H 2O 2 increased the amounts of malondialdenhyde (MDA) and the dehydrogenase (LDH), and decreased the content of nitric oxide (NO) in ECV-304 cells. However, pretreatment with 0.1–50 μmol l −1 icariin resulted in a significant recovery from H 2O 2-induced cell apoptosis. Also, it decreased other H 2O 2-induced damage in a concentration-dependent manner. Furthermore, pretreatment with icariin decreased the expression of caspase-3, which was known to be involved as a key role executor in H 2O 2-induced cell apoptosis. The endothelial cells apoptosis were detected by acridine orange/ethidium bromide (AO/EB) dual staining as well as flow cytometry, and the expression of pro-apoptotic factor caspase-3 were detected by immunocytochemical method. Taken together, these data suggest that protective effects of icariin against oxidative injuries of ECV-304 cells may be achieved via decreasing of caspase expression.

Prevalence of Neurofibromatosis 1 in German Children at Elementary School Enrollment

To determine the prevalence of neurofibromatosis 1 (NF1) among 6-year-old children in Germany. A total of 152819 children aged 6 years in 6 German states were screened for NF1 during routine medical examinations at elementary school enrollment in cooperation with local health departments in 2000 and 2001. The prevalence of NF1 among 6-year-old German children was estimated to be 1:2996 (95% confidence interval, 1:2260 to 1:3984). Fifty-one NF1 cases were identified and confirmed by evaluation by appropriate medical specialists. Seven other children were found to have multiple cafe au lait spots without other apparent features of NF1. A minimum estimate of the crude prevalence was 3.0 per 10 000 (95% confidence interval, 2.3-4.0 per 10 000 population). The incidence of NF1 in this population was probably in the range of 30 to 38 cases per 100 000 live births. Our study obtained a nearly unbiased birth incidence of NF1 of approximately 1 in 2600 to 1 in 3000 and demonstrates that NF1 can be diagnosed by age 6 years in most cases by routine physical examination with special attention to the disease-associated skin stigmata.