The classroom environment and students' reports of avoidance strategies in mathematics: A multimethod study.

The relation between the learning environment (e.g., students' perceptions of the classroom goal structure and teachers' instructional discourse) and students' reported use of avoidance strategies (self-handicapping, avoidance of help seeking) and preference to avoid novelty in mathematics was examined. Quantitative analyses indicated that students' reports of avoidance behaviors varied significantly among classrooms. A perceived emphasis on mastery goals in the classroom was positively related to lower reports of avoidance. Qualitative analyses revealed that teachers in high-mastery/low-avoidance and low-mastery/high-avoidance classrooms used distinctively different patterns of instructional and motivational discourse. High incidence of motivational support was uniquely characteristic of high-mastery/ low-avoidance classrooms, suggesting that mastery goals may include an affective component. Implications of the results for both theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motivation and cheating during early adolescence.

The relations of motivational variables to self-reported cheating behaviors and beliefs in science were examined in a sample of early adolescents. It was hypothesized that cheating and beliefs in the acceptability of cheating would be more likely when students perceived an emphasis on performance and extrinsic incentives rather than on mastery and improvement. Results indicated that students who reported cheating in science perceived their classrooms as being extrinsically focused and perceived their schools as being focused on performance and ability. Students who believed in the acceptability of cheating also reported personal extrinsic goals and a perceived emphasis on extrinsic factors in class. Students who reported cheating also worried about school. The reported use of deep cognitive strategies was related negatively and the use of self-handicapping strategies was related positively to cheating beliefs and behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Development and Validation of Scales Assessing Students'' Achievement Goal Orientations

Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. The number of transducer elements determines the size and weight of the transducer cable assembly that connects the imaging array to the scanner. 2-D arrays that allow new imaging modalities to be introduced significantly increase the channel count making the transducer cable assembly more difficult to handle. Therefore, reducing the size and increasing the flexibility of the transducer cable assembly is a concern. Fiber optics can be used to transmit signals optically and has distinct advantages over standard coaxial cable to increase flexibility and decrease the weight of the transducer cable for larger channel numbers. The use of fiber optics to connect the array and the scanner entails the use of optoelectronics such as detectors and laser diodes to send and receive signals. In transmit, optoelectronics would have to be designed to produce high-voltage wide-bandwidth pulses across the transducer element. In this paper, we describe a 48 channel ultrasound system having 16 optoelectronic transmitters and 32 conventional electronic receivers. We investigated both silicon avalanche photodiodes (APD's) and GaAs lateral photoconductive semiconductor switches (PCSS's) for producing the transmit pulses. A Siemens SI-1200 scanner and a 2.25 MHz linear array were used to compare the optoelectronic system to a conventional electronic transmit system. Transmit signal results and images in tissue mimicking of cysts and tumors are provided for comparison.     

The middle school experience: effects on the math and science achievement of adolescents with LD

A recombinant Fv construct of the B1 monoclonal antibody that recognizes the LewisY-related carbohydrate epitope on human carcinoma cells has been prepared. The Fv is composed of the polypeptide chains of the VH and VL domains expressed independently and isolated as inclusion bodies. The Fv is prepared by combining and refolding equimolar amounts of guanidine chloride solubilized inclusion bodies. The Fv is stabilized by an engineered interchain disulfide bridge between residues VL100 and VH44. This construct has a similar binding affinity as that of the single-chain construct (Benhar and Pastan, Clin. Cancer Res. 1:1023-1029, 1995). The B1 disulfide-stabilized Fv (BldsFv) crystallizes in space group P6(1)22 with the unit cell parameters a = b = 80.1 A, and c = 138.1 A. The crystal structure of the BldsFv has been determined at 2.1-A resolution using the molecular replacement technique. The final structure has a crystallographic R-value of 0.187 with a root mean square deviation in bond distance of 0.014 A and in bond angle of 2.74 degrees. Comparisons of the BldsFv structure with known structures of Fv regions of other immunoglobulin fragments shows closely related secondary and tertiary structures. The antigen combining site of BldsFv is a deep depression 10-A wide and 17-A long with the walls of the depression composed of residues, many of which are tyrosines, from complementarity determining regions L1, L3, H1, H2, and H3. Model building studies indicate that the LewisY tetrasaccharide, Fuc-Gal-Nag-Fuc, can be accommodated in the antigen combining site in a manner consistent with the epitope predicted in earlier biochemical studies (Pastan, Lovelace, Gallo, Rutherford, Magnani, and Willingham, Cancer Res. 51:3781-3787, 1991). Thus, the engineered disulfide bridge appears to cause little, if any, distortion in the Fv structure, making it an effective substitute for the B1 Fab.     

School effects on psychological outcomes during adolescence.

Data from the National Longitudinal Study of Adolescent Health were used to examine school-level differences in the relations between school belonging and various outcomes. In Study 1, predictors of belonging were examined. Results indicated that belonging was lower in urban schools than in suburban schools, and lower in schools that used busing practices than those that did not. In Study 2, the relations between belonging and psychological outcomes were examined. The relations varied depending on the unit of analysis (individual vs. aggregated measures of belonging). Whereas individual students' perceptions of belonging were inversely related to depression, social rejection, and school problems, aggregated belonging was related to greater reports of social rejection and school problems and to higher grade point average. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synergies and tradeoffs between cash crop production and food security: a case study in rural Ghana

Despite dramatic improvements in global crop yields over the past half-century, chronic food insecurity persists in many parts of the world. Farming crops for sale (cash cropping) has been recommended as a way to increase income that can, in turn, improve food security for smallholder farmers. Despite long-term efforts by development agencies and government to promote cash cropping, there is limited evidence documenting a relationship between these crops and the food security of households cultivating them. We used a mixed methods approach to build a case study to assess these relationships by collecting quantitative and qualitative data from cacao and oil palm farmers in the Ashanti region of Ghana. Three dimensions of food security were considered: food availability, measured by the months in a year households reported inadequate food; food access, indicated by the coping strategies they employed to secure sufficient food; and food utilization, gauged by the diversity of household diets and anthropometric measurements of child nutritional status. We found significant negative relationships between each of these pillars of food security and a household’s intensity of cash crop production, measured by both quantity and area. A qualitative assessment indicated community perception of these tradeoffs and identified potential mechanisms, including increasing food prices and competing activities for land use, as underlying causes. The adverse relationship between cash crop production and household food security observed in this paper calls for caution; results suggest that positive relationships cannot be assumed, and that further empirical evidence is needed to better understand these tradeoffs.     

Proposed Measurement of the Beta-Neutrino Correlation in Neutron Decay

Currently, the beta-neutrino asymmetry has the largest uncertainty (4 %) of the neutron decay angular correlations. Without requiring polarimetry this decay parameter can be used to measure λ (g_a/g_v), test Cabibbo-Kobayashi-Maskawa (CKM) unitarity limit scalar and tensor currents, and search for Charged Vector Current (CVC) violation. We propose to measure the beta-neutrino asymmetry coeffcient, a, using time-of-flight for the recoil protons. We hope to achieve a systematic uncertainty of σ_a / a ≈ 1.0 %. After tests at Indiana University’s Low Energy Neutron Source (LENS), the apparatus will be moved to the National Institute of Standards and Technology (NIST) where the measurement can achieve a statistical uncertainty of 1 % to 2 % in about 200 beam days.     

Changes in Achievement Goal Orientations, Perceived Academic Competence, and Grades across the Transition to Middle-Level Schools

Goal orientation theory was used to examine changes in student motivation during the transition from elementary to middle school. Surveys were given to 341 students in the fifth grade in elementary and again in sixth grade in middle school. Students were more oriented to task goals (wanting to improve their competency), perceived a greater emphasis on task goals during instruction, and felt more academically competent in fifth grade in elementary school than in sixth grade in middle school. They perceived a greater emphasis on performance goals (an emphasis on relative ability and right answers) in middle school than in elementary school. Several interactions emerged between year (fifth grade, sixth grade), and both student level of ability (higher, lower, based on standardized achievement tests) and subject domain (math, English).     

A Backscatter Suppressed Electron Detector for the Measurement of “a”

A new method of measuring the electron-antineutrino angular correlation coefficient, little “a”, from neutron decay—to be performed at the National Institute of Standards and Technology—will require an electron spectrometer that strongly suppresses backscattered electrons. A prototype consisting of six trapezoidal veto detectors arranged around a plastic scintillator has been tested with an electron beam produced by a Van de Graaff accelerator. The results of this test and its implications for the little “a” measurement are discussed.