3D Tracking via Body Radio Reflections

This paper introduces WiTrack, a system that tracks the 3D motion of a user from the radio signals reflected off her body. It works even if the person is occluded from the WiTrack device or in a different room. WiTrack does not require the user to carry any wireless device, yet its accuracy exceeds current RF localization systems, which require the user to hold a transceiver. Empirical measurements with a WiTrack prototype show that, on average, it localizes the center of a human body to within 10 to 13 cm in the x and y dimensions, and 21 cm in the z dimension. It also provides coarse tracking of body parts, identifying the direction of a pointing hand with a median of 11.2 degrees. WiTrack bridges a gap between RF-based localization systems which locate a user through walls and occlusions, and human-computer interaction systems like WiTrack, which can track a user without instrumenting her body, but require the user to stay within the direct line of sight of the device

Information Filtering in Electronic Networks of Practice: An fMRI Investigation of Expectation (Dis)confirmation

Online forums sponsored by electronic networks of practice (ENPs) have become an important platform for technology-mediated knowledge exchange, yet relatively little is known about how ENP participants filter and evaluate the information they encounter on these forums. This study integrates perspectives from expectation confirmation theory, prospect theory, and neuroscience research to explore how ENP forum filtering judgments are influenced when expectations formed on the basis of contextual cues are confirmed or disconfirmed by the examination of solution quality. We summarize six different models of expectation confirmation explored in previous IS literature and report the results of a neuroimaging experiment using functional MRI (fMRI) that paired both positive and negative contextual cues with high- and low-quality solutions on a mock ENP forum interface. Results show that evaluation judgments are strongest in conditions where initial contextual cue judgments are confirmed by examination of solution quality except when the perceived expectation-experience gap is large, providing evidence for an assimilation-contrast model of expectation confirmation. We also found neural activation differences for expectation confirmation vs. disconfirmation and, consistent with prospect theory, differences in filtering behaviors with respect to unexpected gains vs. unexpected losses

Pengaruh Pembelajaran Menggunakan Lembar Kerja Siswa Berbasis Problem Based Learning Pada Materi Fluida Statis Terhadap Hasil Belajar Fisika

This study aims to determine the effect of using student worksheet based problem based learning on static fluid material to physics learning outcomes and to improve physics study result.The subjects of this study are students of class XI IPA 6 and 5 SMAN 16 Bandarlampung as many as 64 students. The research design used is Pretest-Posttest Control Group Design. The test result of independent sample t-test obtained tcount>ttable (9.965> 1.670) and significance (0.000≤0.05) mean that there is influence of learning result between experiment class and control class. The average N-gain value in the experimental class is 0.570, while 0.298 for the control class. This means a larger increase when viewed from the difference in average N-gain learning outcomes of experimental class physics with control classes.Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan lembar kerja siswa berbasis problem based learning pada materi fluida statis terhadap hasil belajar fisika dan untuk meningkatkan hasil belajar fisika. Subjek penelitian ini adalah siswa kelas XI IPA 6 dan 5 SMAN 16 Bandarlampung sebanyak 64 siswa. Desain penelitian yang digunakan adalah Pretest-Posttest Control Group Design. Hasil uji independent sample t-test didapatkan nilai thitung>ttabel (9,965>1,670) dan signifikansi (0,000≤0,05) artinya terdapat pengaruh hasil belajar antara kelas eksperimen dan kelas kontrol. Rata-rata nilai N-gain pada kelas eksperimen sebesar 0,570, sedangkan 0,298 untuk kelas kontrol. Artinya terjadi peningkatan yang lebih besar jika dilihat dari perbedaan rata-rata N-gain hasil belajar fisika kelas eksperimen dengan kelas kontrol

Comparing Assessments of Vascular Function via Flow-Mediated Dilation and Rhythmic Handgrip Exercise

Young, otherwise healthy Non-Hispanic Black individuals have been shown to exhibit blunted vascular responsiveness compared to their Non-Hispanic White counterparts, which may be a potential mechanism leading to higher cardiovascular disease risk in this group. Racial differences in vascular function have largely been assessed using flow-mediated dilation (FMD). However, more recent studies have proposed the use of rhythmic handgrip (HG) as an alternative measure of vascular function. PURPOSE: To compare whether rhythmic HG exercise could be an alternative technique to FMD in assessing differences in vascular function between black and white individuals. METHODS: Brachial artery vasodilation was assessed in young healthy black (N = 7; 21 ± 2 years; BMI: 25.5 ± 1.4 kg/m2; mean ± SEM) and white (N = 7; 23 ± 2 years; BMI: 24.0 ± 0.5 kg/m2) men via a standard FMD protocol and rhythmic HG exercise. FMD was assessed by inflating a forearm cuff suprasystolic for 5 min. Rhythmic HG consisted of 3 min HG exercise at 30% of their maximal voluntary contraction (MVC) with a duty cycle of 1-sec contraction/2-sec relaxation. Heart rate (ECG), mean arterial blood pressure (MAP; finger photoplethysmography and automated sphygmomanometer), brachial artery diameter and blood velocity (duplex Doppler ultrasound) were continuously measured during FMD and HG exercise. Brachial artery vasodilation for FMD and rhythmic HG exercise were calculated as a % increase from baseline diameter to peak diameter. RESULTS: Both groups had similar MVCs (black men: 53 ± 1 vs. white men: 54 ± 3 kg; P = 0.80) and resting MAP (black men: 83 ± 2 vs. white men: 85 ± 2 mmHg; P = 0.43). Rhythmic HG dilation (P = 0.72) and FMD (P = 0.43) were not different between groups. Interestingly, white men had greater vasodilation with FMD compared to HG (FMD: 5.76 ± 0.58 vs. HG: 4.13 ± 0.52%; P \u3c 0.01). In contrast, black men had similar vasodilation between FMD and HG (FMD: 4.51 ± 1.01 vs. HG: 4.46 ± 0.89%; P = 0.97). CONCLUSION: These preliminary data suggest that rhythmic HG exercise and FMD provide similar information in the assessment of vascular function between racial groups

Examining IS Curriculum Profiles and the IS 2010 Model Curriculum Guidelines in AACSB-Accredited Schools

The IS 2010 Model Curriculum Guidelines were developed to provide recommendations for standardized information systems curricula while simultaneously allowing for customization within individual programs. While some studies have examined program adherence to the IS 2010 Model Curriculum Guidelines, a more detailed analysis of IS curriculum profiles has not yet been conducted. The purpose of this study is to identify and describe IS curriculum profiles that exist among 127 AACSB IS programs using the IS 2010 guidelines as a framework for analysis. A cluster analysis reveals four distinct profiles of IS program structure: Independent, Focused, Adoptive, and Flexible. Prototypes of each profile are described along with significant differences between each profile as revealed by a discriminant analysis. Identifying and describing these curriculum profiles offers a snapshot of the state of the IS curriculum as a whole and provides a resource for programs seeking to examine and modify their respective curriculum models

Honeycomb Structures for High Shear Flexure

The present invention provides an improved shear band for use in non-pneumatic tires, pneumatic tires, and other technologies. The improved shear band is uniquely constructed of honeycomb shaped units that can replace the elastomeric continuum materials such as natural or synthetic rubber or polyurethane that are typically used. In particular, honeycomb structures made of high modulus materials such as metals or polycarbonates are used that provide the desired shear strains and shear modulus when subjected to stress. When used in tire construction, improvements in rolling resistance can be obtained because of less mass being deformed and reduced hysteresis provided by these materials. The resulting mass of the shear band is greatly reduced if using low density materials. Higher density materials can be used (such as metals) without increasing mass while utilizing their characteristic low energy loss

Effect of Acute Antioxidant Consumption on Cardiac Baroreflex Sensitivity in Young Healthy Adults

There is an emerging body of evidence in animals indicating that elevated oxidative stress impairs baroreflex sensitivity (BRS) function, however studies in healthy humans have yielded equivocal results. One potential reason for this discrepancy is that previous studies have used individual antioxidant treatments (e.g., Vitamin C only) to investigate the effect of oxidative stress on BRS. Recent studies in healthy humans have demonstrated significant reductions in reactive oxygen species using an antioxidant cocktail (AOC; Vitamin C, Vitamin E, and Co-enzyme Q10) suggesting the effectiveness of this treatment. Whether this AOC induced reduction in oxidative species affects BRS in young, healthy adults remains unknown. PURPOSE: We tested the hypothesis that AOC will improve cardiac BRS in young healthy adults. METHODS: Five young men were studied on two separate days: placebo (sugar pills) and AOC (2000 mg Vitamin C, 150 IU Vitamin E and 100 mg Co-enzyme Q10) performed in random order. Resting heart rate (ECG) and arterial blood pressure (automated sphygmomanometer and finger photoplethysmography) were measured 90 minutes after AOC or placebo (a time period this AOC has been shown to have peak effects on oxidative stress). Spontaneous cardiac BRS was determined for all sequences combined (overall BRS), and also separately for up (increase systolic blood pressure: increase R-R interval) and down (decrease systolic blood pressure: decrease R-R interval) sequences. RESULTS: Systolic blood pressure on AOC day tended to be lower relative to the placebo day (127 ± 4 vs. 131 ± 5; p=0.098). However, no differences in overall cardiac BRS were found between placebo and AOC (18.0 ± 2.7 vs.17.3 ± 2.6 ms/mmHg; p=0.59). Likewise, up sequences (17.02 ± 2.9 vs 14.04 ± 4.0 ms/mmHg; p=0.51) and down sequences (18.0 ± 2.7 placebo vs. 18.0 ± 2.6 ms/mmHg AOC; p=0.98) were not different between conditions. Equal number of sequences were found between the placebo and AOC days. CONCLUSION: These preliminary data suggest that antioxidant treatment does not affect resting cardiac BRS in young, healthy men

Reação da cultivar Navelina ISA 315 (Citrus sinensis L. Osb.), à clorose variegada dos citros em condições de campo.

A clorose variegada dos citros (CVC), causada pela bactéria Xylella fastidiosa, está presente no Estado de São Paulo desde 1987. Todas as variedades comerciais de laranjas doces são afetadas. Causa redução da produção, principalmente pela acentuada redução no tamanho dos frutos. (LARANJEIRA et al., 2005). A CVC é transmitida por meio de borbulhas contaminadas e por cigarrinhas das famílias Cicadellidae, em citros existem diversas espécies transmissoras de X. fastidiosa, porém a eficiência na transmissão é inferior a 15%, e este índice pode variar entre espécies em função de mecanismos fisiológicos e comportamentais (YAMAMOTO, 2007; LOPES, 1996). Os sintomas característicos da doença são cloroses internervais amareladas na face superior da folha com correspondente necroses de tons de marrom na face inferior, a frutificação tem tendência de ser em pencas onde os frutos tornam-se rígidos, pequenos e com uma concentração de açúcar maior que o normal (LARANJEIRA et al., 2005).pdf 12

Bone marrow fat is increased in chronic kidney disease by magnetic resonance spectroscopy

In aging, the bone marrow fills with fat and this may lead to higher fracture risk. We show that a bone marrow fat measurement by magnetic resonance spectroscopy (MRS), a newer technique not previously studied in chronic kidney disease (CKD), is useful and reproducible. CKD patients have significantly higher bone marrow fat than healthy adults. INTRODUCTION: Renal osteodystrophy leads to increased morbidity and mortality in patients with CKD. Traditional bone biopsy histomorphometry is used to study abnormalities in CKD, but the bone marrow, the source of osteoblasts, has not been well characterized in patients with CKD. METHODS: To determine the repeatability of bone marrow fat fraction assessment by MRS and water-fat imaging (WFI) at four sites in patients with CKD, testing was performed to determine the coefficients of reproducibility and intraclass coefficients (ICCs). We further determined if this noninvasive technique could be used to determine if there are differences in the percent bone marrow fat in patients with CKD compared to matched controls using paired t tests. RESULTS: The mean age of subjects with CKD was 59.8 ± 7.2 years, and the mean eGFR was 24 ± 8 ml/min. MRS showed good reproducibility at all sites in subjects with CKD and controls, with a coefficient of reproducibilities ranging from 2.4 to 13 %. MRS and WFI assessment of bone marrow fat showed moderate to strong agreement (ICC 0.6-0.7) at the lumbar spine, with poorer agreement at the iliac crest and no agreement at the tibia. The mean percent bone marrow fat at L2-L4 was 13.8 % (95 % CI 8.3-19.7) higher in CKD versus controls (p < 0.05). CONCLUSIONS: MRS is a useful and reproducible technique to study bone marrow fat in CKD. Patients with CKD have significantly higher bone marrow fat than healthy adults; the relationship with bone changes requires further analyses