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The evolution of the dielectric behavior from a dielectric relaxor to a ferroelectric relaxor with variation of Bi concentration in (Sr(sub 1-1.5x)Bi(sub x))TiO3 (0

Abstract: One of the unique features of plasmonic resonances in graphene structures is the enabled tunability through external means. Up to now, electrical gating is extensively adopted to tune graphene plasmonic resonances. This method is, however, limited unfortunately only to graphene structures with electrical connections. Here, a simple and efficient method to tune graphene plasmonic resonances by ultraviolet illuminations in a dynamical and reversible way is demonstrated. It is purely an optical means and can be applied to all kinds of graphene structures without introducing electrodes, ion–gel, or conducting layers required in electrical gating, which is of great significance especially for isolated graphene structures. The optical tuning method could shed new light on graphene‐based tunable devices. [ABSTRACT FROM AUTHOR]

Background: Cytochrome P450 2J2 (CYP2J2) is not only highly expressed in many kinds of human tumors, but also promotes tumor cell growth via regulating the metabolism of arachidonic acids. CYP2J2 inhibitors can significantly reduce proliferation, migration and promote apoptosis of tumor cells by inhibiting epoxyeicosatrienoic acids (EETs) biosynthesis. Therefore screening CYP2J2 inhibitors is a significant way for the development of anti-cancer drug.Purpose: The aim of this study was to identify a new CYP2J2 inhibitor from fifty natural compounds obtained from plants.Study Design: CYP2J2 inhibitor was screened from a natural compounds library and further the inhibitory manner and mechanism were evaluated. Its cytotoxicity against HepG2 and SMMC-7721 cell lines was also estimated.Methods: The inhibitory effect was evaluated in rat liver microsomes (RLMs), human liver microsomes (HLMs) and recombinant CYP2J2 (rCYP2J2), using astemizole as a probe substrate and inhibitory mechanism was illustrated through molecular docking. The cytotoxicity was detected using SRB.Results: In all candidates, plumbagin showed the strongest inhibitory effect on the CYP2J2-mediated astemizole O-demethylation activity. Further study revealed that plumbagin potently inhibited CYP2J2 activity with IC50 value at 3.82 µM, 3.37 µM and 1.17 µM in RLMs, HLMs and rCYP2J2, respectively. Enzyme kinetic studies showed that plumbagin was a mixed-type inhibitor of CYP2J2 in HLMs and rCYP2J2 with Ki value of 1.88 µM and 0.92 µM, respectively. Docking data presented that plumbagin interacted with CYP2J2 mainly through GLU 222 and ALA 223. Moreover, plumbagin showed strongly cytotoxic effects on hepatoma cell lines, such as HepG2 and SMMC-7721, with lower toxicity on rat primary hepatocytes. Plumbagin had no effect on the protein expression of CYP2J2 in HepG2 and SMMC-7721, while down-regulated the mRNA level of anti-apoptosis protein Bcl-2.Conclusion: This study found out a new CYP2J2 inhibitor plumbagin from fifty natural compounds. Plumbagin presented a potential of anti-cancer pharmacological activity. [ABSTRACT FROM AUTHOR]

Based on the job demands--resources model, the study developed and validated an instrument that measures physical education teachers' job demands--resources perception. Expert review established content validity with the average item rating of 3.6/5.0. Construct validity and reliability were determined with a teacher sample (n = 397). Exploratory factor analysis established a five-dimension construct structure matching the theoretical construct deliberated in the literature. The composite reliability scores for the five dimensions range from .68 to .83. Validity coefficients (intraclass correlational coefficients) are .69 for job resources items and .82 for job demands items. Inter-scale correlational coefficients range from -.32 to .47. Confirmatory factor analysis confirmed the construct validity with high dimensional factor loadings (ranging from .47 to .84 for job resources scale and from .50 to .85 for job demands scale) and adequate model fit indexes (root mean square error of approximation = .06). The instrument provides a tool to measure physical education teachers' perception of their working environment. [ABSTRACT FROM AUTHOR]

The hog deer (Axis porcinus) is a small deer whose natural habitat is the wet or moist tall grasslands in South and Southeast Asia. Wild populations have dramatically decreased in recent decades. While wild hog deer were recently acknowledged to be extinct in China, a few captive populations have been maintained. In the present study, we successfully employed the restriction-site-associated DNA sequencing (RAD-seq) technique to generate a genome-wide profile of single-nucleotide polymorphisms (SNPs) in the captive population of hog deer from Chengdu Zoo, China (N = 11). Up to 4.7 million clean reads per sample were sequenced, and 11,155 SNPs and 8,247 haplotypes were simultaneously observed within more than 80% of sequenced individuals. In this population, the mean frequency of major alleles at each polymorphism site was 0.7903±0.0014, and the average nucleotide diversity (π) and inbreeding coefficient (FIS) were 0.3031±0.0015 and -0.0302±0.0062, respectively. Additionally, the Euclidean distance-based multidimensional scaling method revealed that the pairwise genetic relatedness was evenly distributed. However, the results of homologous searching by short reads did not provide any meaningful explanation of the phylogenetic relationship of hog deer, which should be further investigated. In conclusion, our results revealed current state of genetic diversity in this captive population of hog deer.Furthermore, these genome-wide SNPs would be useful for guiding the mating schedule to avoid sharp increase of inbreeding coefficient. [ABSTRACT FROM AUTHOR]

Wetlands are important habitats on biodiversity protection. In this study, the relationship between wetland and avifauna changes in the Yellow River Delta Wetland was studied. Remote sensing and geographic information system provided an advanced platform for the research. After the avifauna survey was performed from 2012 to 2013, the birds’ variation and driving factors were analyzed. The results showed that the flow into the wetland increased continuously from 2000, and the increased of artificial wetland prevented the wetland degradation, although at the same time the total wetland area decreased. Medium grassland, tidal flat and pond are the three main landscapes which are beneficial for the habitation of birds. The migrating numbers of red-crowned crane increased significantly from 2005, and the overwintering numbers increased from 2009. The study results show that the key land use types for protecting endangered species of birds are medium grassland, tidal flat and pond landscapes. Wetland changes are sensitive to the birds and significantly affected by the flow. We suggest that the artificial wetland project should enhance the three land use type area to ensure the wetland restoration. [ABSTRACT FROM AUTHOR]

HC290 is a substitute for R22 and R410A for small heat pumps, room air conditioners, and light commercial refrigeration equipment since it has a negligible environmental impact and high efficiency. The performance, P-V diagram and valve dynamic displacement of a rotary compressor using R22 and R290 as the refrigerant, under five different operating conditions, were measured and analyzed in this paper to help understand the characteristics of internal thermodynamic process and the distribution of indicated power losses. Further, a new method for analyzing the P-V diagram of a rotary compressor was proposed. Compared with the R22 compressor, some conclusions about the discharge process starting angle, dynamic variation of pressure in the cylinder, volumetric efficiency, indicated efficiency, and loss distribution of the R290 rotary compressor under high efficiency conditions were given. The performance variation of the R290 compressor under other conditions was explained. Several measures to increase the energy efficiency of the R290 rotary compressor were proposed. [ABSTRACT FROM AUTHOR]

This work reported a high quality photonic crystal film with an ultra-narrow photonic bandgap obtained via a chemical synthetic route. The bandgap is much narrower than that of traditional colloidal crystals, which makes the film qualified for use in optical devices. The narrow PBG originates from not only the high crystallinity and uniform orientations of microcrystals within the film but also the very close refractive indices between the silica and the polymer matrix. Due to the matching of the refractive index, the amorphous contents of the film are optically transparent and do not interfere with the reflection, so that the photonic crystal film is tolerant of the existence of disordered contents. [ABSTRACT FROM AUTHOR]

The research on oil discharge ratio (ODR) of rotary compressors used for room air conditioners is very important to improve the performance and reliability of the compressors and their systems. This paper presents a detailed computational fluid dynamics (CFD) simulation model for the refrigerant gas flow and oil droplet flow within the shell of the compressor, which is used for investigating ODR of the compressor subjected to design changes or under different operating speeds. The geometry of the rotary compressor and its oil separating burden was presented. The CFD simulation is based on the discrete phase model (DPM). The oil droplet size distribution was defined by the Rosin–Rammler diameter distribution method. The boundary conditions of the refrigerant gas and oil droplets were established. Validation of the CFD model has been made by measuring ODR of a rotary compressor used in the high efficiency air room conditioner for different design configurations and an inverter rotary compressor with R410A. The simulation ODRs of the compressor agree within 11% of the experimental-measured ODRs. The ODR of compressor could be reduced effectively by some technique. [ABSTRACT FROM AUTHOR]

Purpose:A primary goal of physical education is to develop physically literate individuals with the knowledge, skills, and confidence necessary for a physically active lifestyle. Guided by the expectancy-value and interest motivation theories, the purpose of this study was to identify the relationship between students' motivation and health-related fitness knowledge developed in physical education and their after-school physical activity participation.Method:Third-, 4th-, and 5th-grade students (N = 293) from 6 elementary schools in a large metropolitan school district in the United States provided data on expectancy beliefs and perceived task values, situational interest, health-related fitness knowledge, and after-school physical activity. Data were analyzed using descriptive statistics and a simultaneous multiple regression model.Results:It was found that expectancy beliefs (β = .20,t = 2.16,p = .03) and perceived exploration demand (β = .25,t = 2.58,p = .01), a source for situational interest, were positively related to after-school physical activity. The 2 variables, however, accounted for only 11.2% of the variances for children's after-school physical activity participation.Conclusion:This study demonstrates that students' active exploration and expectancy beliefs for success in physical education have limited influence on leisure-time physical activity participation. [ABSTRACT FROM PUBLISHER]

In physical education, it has become necessary for children to learn kinesiological knowledge for understanding the benefits of physical activity and developing a physically active lifestyle. This study was conducted to determine the extent to which cognitive assignments about healthful living and fitness contributed to knowledge growth on cardiorespiratory fitness and health. Fourth grade students (N = 616) from 15 randomly sampled urban elementary schools completed 34 cognitive assignments related to the cardiorespiratory physical activities they were engaged in across 10 lessons. Performance on the assignments were analyzed in relation to their knowledge gain measured using a standardized knowledge test. A multivariate discriminant analysis revealed that the cognitive assignments contributed to knowledge gain but the contribution varied assignment by assignment. A multiple regression analysis indicated that students’ assignment performance by lesson contributed positively to their knowledge growth scores. A content analysis based on the constructivist learning framework showed that observing–reasoning assignments contributed the most to knowledge growth. Analytical and analytical–application assignments contributed less than the constructivist theories would predict. [ABSTRACT FROM PUBLISHER]

The pore and throat structure of tight oil reservoir cores is complex, and the resistance of oil drop to discharge from the core is very high during dynamic imbibition. Surfactant has good ability in interfacial tension reduction and wettability reversal. It can reduce oil drop discharge resistance and enhance oil recovery effectively during dynamic imbibition in tight reservoirs. Here, we first analyzed the pore throat structure and mineral composition of tight core, and then the oil drop visualization instrument was used to study the discharge behavior of oil drop during dynamic imbibition. The oil drop discharge form was analyzed, and the influence of various factors on the oil drop discharge behavior was explored, and then the dynamic imbibition performance of surfactant in tight cores was obtained. The core throat diameter was mainly distributed in 0.07–1.1 μm, and the hydrophilic mineral content in core reached 50.8%. In the case of fluid flow in fracture, the oil drop discharge from near fracture matrix was faster, and its growth rate in height and width was faster than that without external fluid flow. Within a certain range, with the increase of IFT, the rate of core imbibition increased gradually. When the IFT increased from 0.32 mN/m to 0.59 mN/m, the oil drop rapture time decreased by 66.3%. The growth rate of oil drop discharged from the top and side of the core was faster than that from the bottom surface. Furthermore, it was easier to discharge. With the core thickness reduced by half, the rapture time of oil drop was reduced by 74.7%. For tight reservoirs, hydraulic fracturing can create more fracture surfaces and reduce the size of matrix blocks, which contributes to reduce the oil drop discharge resistance during imbibition and improve the oil recovery. This study provides a basis for surfactant to improve dynamic imbibition and oil production performance of tight sandstone oil reservoir. [ABSTRACT FROM AUTHOR]

Temperature and precipitation are considered to be the most important indicators affecting the green-up date. Sensitivity of the green-up date to temperature and precipitation is considered to be one of the key indicators to characterize the response of terrestrial ecosystems to climate change. We selected the main grassland types for analysis, including temperate steppe, temperate meadow steppe, upland meadow, and lowland meadow. This study investigates the variation in key meteorological indicators (daily maximum temperature (Tmax), daily minimum temperature (Tmin), and precipitation) between 2001 and 2018. We then examined the partial correlation and sensitivity of green-up date (GUD) to Tmax, Tmin, and precipitation. Our analysis indicated that the average GUD across the whole area was DOY 113. The mean GUD trend was −3.1 days/decade and the 25% region advanced significantly. Tmax and Tmin mainly showed a decreasing trend in winter (p > 0.05). In spring, Tmax mainly showed an increasing trend (p > 0.05) and Tmin a decreasing trend (p > 0.05). Precipitation showed no significant (p > 0.05) change trend and the trend range was ±10 mm/decade. For temperate steppe, the increase in Tmin in March promotes green-up (27.3%, the proportion of significant pixels), with a sensitivity of −0.17 days/°C. In addition, precipitation in April also promotes green-up (21.7%), with a sensitivity of −0.32 days/mm. The GUDs of temperate meadow steppe (73.9%), lowland meadow (65.9%), and upland meadow (22.1%) were mainly affected by Tmin in March, with sensitivities of −0.15 days/°C, −0.13 days/°C, and −0.14 days/°C, respectively. The results of this study reveal the response of vegetation to climate warming and contribute to improving the prediction of ecological changes as temperatures increase in the future. [ABSTRACT FROM AUTHOR]

Abstract: Physical education and health education are relevant avenues for adolescents to learn knowledge and behavior related to energy-balanced living. Grounded in the framework theory of conceptual change, this study examined ninth graders' energy balance knowledge (i.e., concepts, principles, and strategies underlying the scientific mechanism and the outcome of energy balanced/imbalanced living) and physical activity in a healthful-living curriculum (i.e. combination of physical education and health). The students (N =195) were measured using concept mapping, accelerometers, and three-day physical activity recall. It was found that the students differed in energy balance knowledge where most (83%) lacked a higher-order relational understanding. Physical activity in physical education class or after school did not significantly differ by students' mental model levels concerning energy balance knowledge. The findings suggest that an ecological learning context with moderate physical activity should be provided to help students make sense of energy balance knowledge through lived experiences. [Copyright &y& Elsevier]

Physical activity is critical to healthy development of children. It is well documented that helping children develop and sustain a physically active lifestyle requires children to become motivated. Many studies have been conducted in the past 2.5 decades on determinants and correlates for children and adolescents' physical activity motivation. The findings have informed researchers and practitioners about motivation sources for children and effective strategies to motivate children in given physical activity settings. Built on the extensive knowledge base and theoretical platforms formed by these research studies, the purpose of this article is to take a look at the current research landscape and provide subjective thoughts about what we still need to know about children's physical activity motivation. The product of this subjective thinking process rendered 10 potential questions for future research on children's physical activity motivation in both in-school and out-of-school settings. These topics encompass those focusing on children's physical activity motivation as a mental dispositional process, those conceptualizing the motivation as an outcome of person–environment interactions, and those attempting to dissect the motivation as an outcome of social–cultural influences and educational policies. It is hoped that the topics can serve researchers interested in children's physical activity motivation as starting blocks from which they can extend their conceptual thinking and identify research questions that are personally meaningful. It is also hoped that the list of potential questions can be helpful to researchers in accomplishing the imperative and significant mission to motivate children to be physically active in the 21st century and beyond. [ABSTRACT FROM PUBLISHER]

• The RSDI is suitable for monitoring aeolian desertification. • The areas with significant restoration (34.1%) exceeded those with significant deterioration (6%) in the NSPB. • In the areas with significant restoration, 57.4% of the land was mainly affected by human activities. The northern sand-prevention belt (NSPB) is the key area for sand control in China, and the various ecological projects conducted there are important to the Chinese strategy for ecological security. In this paper, a new remote sensing-based desertification index (RSDI) based on principal component analysis was constructed from four aspects of vegetation greenness, surface moisture, soil grain size, and surface radiation. The overall evaluation accuracy of the index was 89.2%, and the kappa coefficient was 0.80, indicating high sensitivity to different degrees of aeolian desertification and suitability for multiscale research. The coefficient of variation, Mann–Kendall test, Theil–Sen median trend analysis, and residual analysis were used to analyze the spatiotemporal changes and driving forces of the RSDI in the NSPB from 2000 to 2020. The RSDI was used to compare aeolian desertification in different subregions, land use types, and ecological project areas. The important results are as follows: (1) the trend of the average RSDI was downward, but it increased significantly in 2008–2009 and 2013–2014; (2) the RSDI was characterized by relatively high volatility in 28.9% and moderate volatility in 27.1% of the area; (3) the areas with significant restoration (34.1%) greatly exceeded those with significant deterioration (6%), whereas 59.9% of the total area was stable; and (4) within the area with significant restoration, 57.4% was primarily affected by human activities, and 42.4% was primarily affected by climate change; however, most of the area with significant deterioration (71.1%) was affected by human activities. In general, the degree of aeolian desertification in the NSPB has decreased in the past 20 years and its ecological quality has continued to recover. However, unreasonable human activities still need to be reduced, and the ecological management of areas under serious threat of desertification needs to be strengthened. [ABSTRACT FROM AUTHOR]

Expectancy value theory presumes that learners’ motivation is determined by their expectancy beliefs and task values associated with learning tasks. This study examined students’ cost and its relation to expectancy beliefs, other task value components in physical education. Middle school students (N = 593) from 11 schools completed the expectancy-value questionnaire. Qualitative analysis of students’ responses to open-ended questions showed motivational cost originated from curriculum content, instructional conditions/elements, physical discomfort, lack of social support and competence and teacher factors. Chi-square analysis suggests that students’ motivational cost is associated with their hypothetical choices of attending physical education. Motivational cost was found to be negatively associated with other task value components, but not with expectancy beliefs. [ABSTRACT FROM AUTHOR]

Motivation to learn is a disposition developed through exposure to learning opportunities. Guided by the expectancy-value theory of Eccles and Wigfield (1995), this study examined the extent to which expectancy belief and task value influenced elementary school students’ physical activity and knowledge learning in physical education (PE). Students (N = 753) from 15 US public schools contributed student-level and class-level data. With a 2-level design, the data were analyzed using hierarchical linear modeling. Physical activity (t = 3.18; p < .01) positively predicted fitness knowledge. Attainment value (i.e. perception of importance) as the only expectancy-value construct, significantly predicted fitness knowledge (t = 3.07; p < .01), when physical activity was held constant. As the physical activity intensity increased, the positive prediction of attainment value to knowledge attenuated and then turned negative (t = –3.10; p < .01). The study indicated that although a physically-active context helps students to make sense of fitness knowledge, a vigorous context shifts their motivation away from cognitive learning, toward physical participation. To resolve the difficulty of attaining learning objectives both physically and cognitively, PE teachers may want to maintain an active learning context with moderate physical intensity. Future research should address the effect of learner motivation on dual or multiple learning outcomes in PE. [ABSTRACT FROM AUTHOR]

Expectancy-Value Questionnaire (EVQ) measures student expectancy beliefs and task values of the domain content (Eccles & Wigfield, 1995).In this study the authors examine measurement invariance of EVQ in the domain of physical education between elementary and middle-school students. Participants included 811 students (3rd–5th grades) from 13 elementary and 903 (6th–8th grades) from 13 middle schools. Students completed the EVQ in their physical education classes within the same semester. A series of hierarchical steps for testing the measurement invariance were conducted based on means and covariance structures. The results suggest that the questionnaire possesses configural and metric invariance, but noninvariant item intercepts between these two groups of students (∆CFI > .05). EVQ can be used to measure expectancy-value constructs in physical education for both middle-school and elementary students. Yet the noninvariant item intercepts posted questions on how the measured construct difference should be interpreted. [ABSTRACT FROM AUTHOR]

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Background: Curriculum fidelity describes the extent to which a curriculum is implemented faithfully as planned. Curriculum fidelity issues may arise when teachers implement the curriculum inconsistently due to differences in philosophy, barriers in the setting, or other local concerns. Purpose: The study examined challenges that a teacher faced in implementing a constructivist physical education curriculum that had fidelity implications. Research design: Ethnographic case study design was employed in the research. Participants and setting: One physical education teacher, 'Daniel', and his students in the third, fourth, and fifth grades participated in the study as they were involved in a curriculum intervention in a large urban school district in the US. Daniel's school was randomly assigned to an experimental group to implement a physical education curriculum based on health/fitness-related science. Data collection: The researchers observed 75 lessons taught by Daniel using non-participant observation techniques and conducted two structured interviews with Daniel and eight interviews with his students. Data analysis: Constant comparison with open and axial coding was used to analyze the observation and interview data. Findings: Two thematic challenges emerged: (1) school contextual constraints that limited the fitness science learning environment in physical education, and (2) Daniel's personal values and preference for a recreational rather than a science-based physical education program. These challenges impacted Daniel's decisions when teaching the curriculum. [ABSTRACT FROM AUTHOR]

Abstract: This study reports adolescent expectancy-value motivation, and its relation to fitness knowledge and psychomotor skill learning in physical education. Students (N =854) from 12 middle schools provided data on expectancy-value motivation, fitness knowledge and psychomotor skill learning. Results from dependent t-test and MANOVA indicated that 8th grade students rated task values significantly lower than 6th grade while their expectancy beliefs did not significantly differ. Students gained sizable fitness knowledge (d =0.58, p <0.05) and badminton skill (d =1.40, p <0.05). Multiple regression analyses revealed that expectancy-value motivation did not significantly predict learning in fitness knowledge or psychomotor skills. These findings suggest that expectancy-value motivation might predict engagement and performance, but not necessarily learning achievement in physical education. [Copyright &y& Elsevier]

Abstract: Ceramic samples with nominal compositions of (Ca1− x Sr x )0.9Pr0.001Zn0.099TiO3 (x =0, 0.05, 0.10, 0.15, 0.20) were prepared by a mixed oxide method. When examined by the X-ray diffraction (XRD) analysis, the samples revealed a main CaTiO3 phase with small amounts of a second Zn2TiO4 phase. All of the ceramic samples emitted red phosphorescent light at about 613nm when excited by light of a wide wavelength range (200nm to about 500nm). The partial substitution of Sr for Ca, up to approximately 10at%, significantly enhanced the phosphorescence intensity and lifetime. The long lasting phosphorescence could be observed with naked eyes in dark room for more than 10min in both air and water at room temperature. [Copyright &y& Elsevier]

Ceramic samples with the nominal composition (1− x) BaTiO3+ x Ba3Ti2YO8.5 ( x=0−0.535) were prepared by the mixed oxide method. X-ray diffraction (XRD) analysis shows that the materials are of single phase with a cubic symmetry as x≤0.16. The compositions of the solid solutions ( x≤0.16) can be expressed equivalently as Ba(Ti1− yY y)O3−δ ( y≤0.122, y= x/(1+2 x)). For x>0.16, the materials are diphasic composites consisting of Ba(Ti1− yY y)O3 ( y=0.122) and Ba3Ti2YO8.5. The microstructure observation by scanning electron microscopy supports the XRD result. The dielectric behavior and phase transitions of the solid solutions ( x≤0.16) vary with different Y concentrations. The dielectric constant of the composites ( x>0.16) follows approximately the Lichteneker relation in a wide temperature range. [ABSTRACT FROM AUTHOR]

The crystalline structure, microstructure and dielectric properties of the (Sr1-1.5xBix)TiO3 (0 ≤ x ≤ 0.267) ceramics were studied. Cubic solid solutions were determined for x ≤ 0.2 at room temperature. However, lattice distortion was detected by Raman spectra. A dense microstructure with the grain sizes of 2-4 µm was obtained for (Sr1-1.5xBix)TiO3 (0 ≤ x ≤ 0.2) ceramics. The Bi concentration was examined and found to be in agreement with the nominal composition and overall uniformly distributed in the sample. Different from the observations in the earlier literature for other doped quantum paraelectrics, where only an induced dielectric anomaly was reported, there are three Bi induced dielectric modes A, B, and C in the Bi doped SrTiO3 samples. The occurrence of the "impurity modes" and the "ferroelectric relaxor mode" and their evolution are demonstrated as a function of Bi concentration. [ABSTRACT FROM AUTHOR]

Background. Situational interest is articulated theoretically as a construct associated with five dimensional sources: novelty, challenge, attention demand, exploration intention, and instant enjoyment. Aims. This study aimed to examine the influence of the dimensional sources on situational interest. It was hypothesised that the dimensional sources function differently to contribute to situational interest and that the influence of a source might be mediated by others. Sample. Two samples of 7th, 8th, and 9th grade students were used in the study. There were 281 students (57% male, 43% female) in the first sample and 191 (47% male, 53% female) in the second. Method. Students in Sample A evaluated situational interest and the dimensional sources in tasks of analysing jogging and gymnastic stunts on video. Those in Sample B evaluated them in tasks of learning basketball. Correlation and regression analyses and path analyses were used to test the theoretical model. Results. Instant Enjoyment determined situational interest. Exploration and Novelty had positive influences on situational interest via enhancing Instant Enjoyment. Challenge showed little influence. The path analyses for both samples confirmed the inter-dimensional mediation effects of the sources. Conclusion. The analysed data support the hypotheses. The dimensional sources had unequal influences on situational interest and the mediation effects among themselves at times strengthened or weakened each other's influences. The findings suggest that to increase situational interest, educators should offer students ample exploratory opportunities during student-task interaction that can lead to instant enjoyment for learning. [ABSTRACT FROM AUTHOR]

Northern China has been long threatened by aeolian desertification. In recent years, all levels of the Chinese government have performed a series of ecological protection and sand control projects. To grasp the implementation effects of these projects and adjust policies in time, it is necessary to understand the process of aeolian desertification quickly and accurately. Remote sensing technologies play an irreplaceable role in aeolian desertification monitoring. In this study, the Zhenglan Banner, which is in the hinterland of the Hunshandake Sandy Land, was considered as the research area. Based on unmanned aerial vehicle (UAV) images, ground survey data, and Landsat images called in Google Earth Engine (GEE), the aeolian desertified land (ADL) in 2000, 2004, 2010, 2015, and 2019 was extracted using spectral mixture analysis. A desertification index (DI) was constructed to evaluate the spatial and temporal dynamics of the ADL in the Zhenglan Banner. Finally, a residual analysis explored the driving forces of aeolian desertification. The results showed that (1) the ADL area in the Zhenglan Banner has been trending downwards over the past 20 years but rebounded from 2004 to 2010; (2) over the past 20 years, the area of slightly, moderately, and severely desertified land has decreased at annual rates of 0.4%, 2.7%, and 3.4%, respectively; (3) human activities had significantly positive and negative impacts on the aeolian desertification trend for 20.0% and 21.0% of the study area, respectively, but not for the rest. This paper explored new techniques for rapid aeolian desertification monitoring and is of great significance for controlling and managing aeolian desertification in this region. [ABSTRACT FROM AUTHOR]

The accumulation of heat and moderate precipitation are the primary factors that are used by grasslands to trigger a green-up date. The accumulated growing degree-days (AGDD) requirement over the preseason is an important indicator of the response of grassland spring phenology to climate change. This study adopted the Normalized Difference Phenology Index (NDPI), which derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), to extract annual green-up dates in the Hulun Buir grassland in China between 2001–2015. Our analysis indicated that the range (standard deviation) and trend for the green-up date were DOY (day of year) 104 to DOY 144 (10.6 days) and −2.0 days per decade. Nine point two percent of the study area had significant (p < 0.05) changes in AGDD requirements. The partial correlations between the AGDD requirements and chilling days (67.04%, pixels proportion) were negative and significant (p < 0.05). The partial correlations between the AGDD requirement and precipitation (28.87%) were positive and significant (p < 0.05). Finally, the partial correlation between the AGDD requirement and insolation (97.65%) were positive and significant (p < 0.05). The results of this study could reveal the response of vegetation to climate warming and contribute to improving the phenological mechanism model of different grassland types in future research. [ABSTRACT FROM AUTHOR]

Respiratory behaviors provide useful measures of lung health. The current methods have limited capabilities of continuous characterization of respiratory behaviors, often required to assess respiratory disorders and diseases. This work presents a system equipped with a machine learning algorithm, capable of continuously monitoring respiratory behaviors. The system, consisting of two wireless wearable sensors, accurately extracts and classifies the features of respiratory behaviors of subjects within various postures, wirelessly transmitting the temporal respiratory behaviors to a laptop. The sensors were attached on the midway of the xiphoid process and the costal margin, and 1 cm above the umbilicus, respectively. The wireless wearable sensor, consisting of ultrasound emitter, ultrasound receiver, data acquisition and wireless transmitter, has a small footprint and light weight. The sensors correlate the mechanical strain at wearing sites to lung volume by measuring the local circumference changes of the chest and abdominal walls simultaneously. Eleven subjects were recruited to evaluate the wireless wearable sensors. Three different random forest classifiers, including generic, individual, and weighted-adaptive classifiers, were used to process the wireless data of the subjects at four different postures. The results demonstrate the respiratory behaviors are individual- and posture-dependent. The generic classifier merely reaches the accuracy of classifying postures of 21.9 ± 1.7% while individual and weighted-adaptive classifiers mark substantially high, up to 98.9 ± 0.6% and 98.8 ± 0.6%, respectively. The accurate monitoring of respiratory behaviors can track the progression of respiratory disorders and diseases, including chronic respiratory obstructive disease (COPD), asthma, apnea, and others for timely and objective approaches for control. • Continuously monitor and extract features of respiratory behaviors completely and accurately. • Machine-learning enabled study of individuality of respiratory behaviors. • Postures recognition based on general respiration contributing to monitor posture-related respiratory diseases, like apnea. [ABSTRACT FROM AUTHOR]

Examines the multidimensionality of situational interest in physical education among middle school students in the United States. Use of Development and revision of the Situational Interest Scale; Dimensions of situational interest; Employment of exploratory and confirmatory factor analysis; Definition of situational interest.

Focuses on educational value orientations which reflect teachers' philosophical beliefs about schooling which serve as the basis on which teachers make their decisions. What the subsequent examination of the representativeness of the statment led to; Purpose of the investigation.

Examines the patterns of holding interest for physical activities in a state physical education curriculum for secondary schools. Determination and analysis of patterns; Types of interest; Activities associated with patterns; Basis of holding interest; Focus for curricular decisions.

Describes physical educators' value orientations for curricular decision making in urban and rural teaching settings. Role of beliefs in curricular decision making; Priority on self-actualization and social responsibility; Differences in school contexts in urban and rural schools.

Discusses the domain specifications and content representativeness of the revised value orientation inventory (VOI) for physical education teachers. VOI revision process; Disciplinary mastery; Learning process; Self-actualization; Ecological integration; Social reconstruction.