Equilibrium or Simple Rule at Wimbledon? An Empirical Study

We follow Walker and Wooders’(2001) empirical analysis to collect and study a broader data set in tennis, including male, female and junior matches. We find that there is mixed evidence in support of the minimax hypothesis. Granted, the plays in our data pass all the tests in Walker and Wooders (2001). However, we argue that not only the test on equal winning probabilities may lack power, but also the current serve choices may depend on past serve choices, the performance of past serve choices, or the time that the game has elapsed. We therefore examine the role that simple rules may play in determining the plays. For a significant number of top tennis players, some simple low-information rules outperform the minimax hypothesis. By comparing junior players with adult players, we find that the former tend to adopt simpler rules. The result of comparison between female and male players is inconclusiveminimax, learning, low-information

Structural analysis from system configurations for modeling and design of multi-energy domain dynamic systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.Includes bibliographical references (leaves 146-151).by Shih-Ying Huang.Ph.D

Analysis of a time delay controller based on convolutions, with application to a cruise control system

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1993.Includes bibliographical references (leaves 60-63).by Shih-Ying Huang.M.S

Effects of cord pretension and stiffness of the Dynesys system spacer on the biomechanics of spinal decompression- a finite element study

BACKGROUND: The Dynesys system provides stability for destabilized spines while preserving segmental motion. However, clinical studies have demonstrated that the Dynesys system does not prevent adjacent segment disease. Moreover, biomechanical studies have revealed that the stiffness of the Dynesys system is comparable to rigid fixation. Our previous studies showed that adjusting the cord pretension of the Dynesys system alleviates stress on the adjacent level during flexion. We also demonstrated that altering the stiffness of Dynesys system spacers can alleviate stress on the adjacent level during extension of the intact spine. In the present study, we hypothesized that omitting the cord preload and changing the stiffness of the Dynesys system spacers would abate stress shielding on adjacent spinal segments. METHODS: Finite element models were developed for - intact spine (INT), facetectomy and laminectomy at L3-4 (DEC), intact spine with Dynesys system (IntDyWL), decompressed spine with Dynesys system (DecDyWL), decompressed spine with Dynesys system without cord preload (DecDyNL), and decompressed spine with Dynesys system assembled using spacers that were 0.8 times the standard diameter without cord pretension (DecDyNL0.8). These models were subjected to hybrid control for flexion, extension, axial rotation; and lateral bending. RESULTS: The greatest decreases in range of motion (ROM) at the L3-4 level occurred for axial rotation and lateral bending in the IntDyWL model and for flexion and extension in the DecDyWL model. The greatest decreases in disc stress occurred for extension and lateral bending in the IntDyWL model and for flexion in the DecDyWL model. The greatest decreases in facet contact force occurred for extension and lateral bending in the DecDyNL model and for axial rotation in the DecDyWL model. The greatest increases in ROMs at L2-3 level occurred for flexion, axial rotation and lateral bending in IntDyWL model and for extension in the DecDyNL model. The greatest increases in disc stress occurred for flexion, axial rotation and lateral bending in the IntDyWL model and for extension in the DecDyNL model. The greatest increases in facet contact force occurred for extension and lateral bending in the DecDyNL model and for axial rotation in the IntDyWL model. CONCLUSIONS: The results reveals that removing the Dynesys system cord pretension attenuates the ROMs, disc stress, and facet joint contact forces at adjacent levels during flexion and axial rotation. Removing cord pretension together with softening spacers abates stress shielding for adjacent segment during four different moments, and it provides enough security while not jeopardizes the stability of spine during axial rotation

Active Solders and Active Soldering

Due to the relatively high stability of ceramic surfaces, ceramics, graphite, and alloys that easily form an oxide passivation layer by natural oxidation, such as aluminum alloys, titanium alloys, and magnesium alloys, are not wetted by common solders and brazing fillers. Moreover, in most applications, the brazing temperature is so high that it causes hot cracking or functional degradation of the difficult-to-wet materials. Active filler metals containing active elements have been developed, which can successfully join the nonwetting materials at low temperatures (<250°C) in air. The active elements, such as titanium, magnesium, and rare earth elements, in active solders play an important role in wettability and reactivity between filler metals and difficult-to-wet materials. Solders with active element content have been shown to provide excellent wettability. Hence, direct active soldering has been developed to simplify the manufacturing of difficult-to-wet material joints. A practical understanding of the design and characterization of low melting point active solders and active soldering processes is elaborated in this chapter. The effects of active elements, active solder characteristics, mechanism of active soldering, active soldering techniques, and specific applications are introduced. The influence of the thermal and mechanical activation on the interfacial reactions between filler metals and difficult-to-wet materials during the active soldering process is also discussed

Temporal Arteritis

Temporal arteritis, a chronic inflammatory vasculitis involving medium- and large-sized arteries, has rarely been reported in Asia. However, we report 2 cases, in which the patients initially presented with headache. Physical examination disclosed engorged, hard and palpable vessels in the temporal areas. Temporal-artery biopsy revealed 2 different types of arteritis: the multinucleated giant cell type and the panarteritis type without multinucleated giant cells. One patient was positive for immunoglobulin G anticardiolipin antibody. The pathologic findings of the different subsets of temporal arteritis, and the relationship between anticardiolipin antibody and the extent of vascular complications of temporal arteritis, are discussed

Exploration of PET and MRI radiomic features for decoding breast cancer phenotypes and prognosis.

Radiomics is an emerging technology for imaging biomarker discovery and disease-specific personalized treatment management. This paper aims to determine the benefit of using multi-modality radiomics data from PET and MR images in the characterization breast cancer phenotype and prognosis. Eighty-four features were extracted from PET and MR images of 113 breast cancer patients. Unsupervised clustering based on PET and MRI radiomic features created three subgroups. These derived subgroups were statistically significantly associated with tumor grade (p = 2.0 × 10-6), tumor overall stage (p = 0.037), breast cancer subtypes (p = 0.0085), and disease recurrence status (p = 0.0053). The PET-derived first-order statistics and gray level co-occurrence matrix (GLCM) textural features were discriminative of breast cancer tumor grade, which was confirmed by the results of L2-regularization logistic regression (with repeated nested cross-validation) with an estimated area under the receiver operating characteristic curve (AUC) of 0.76 (95% confidence interval (CI) = [0.62, 0.83]). The results of ElasticNet logistic regression indicated that PET and MR radiomics distinguished recurrence-free survival, with a mean AUC of 0.75 (95% CI = [0.62, 0.88]) and 0.68 (95% CI = [0.58, 0.81]) for 1 and 2 years, respectively. The MRI-derived GLCM inverse difference moment normalized (IDMN) and the PET-derived GLCM cluster prominence were among the key features in the predictive models for recurrence-free survival. In conclusion, radiomic features from PET and MR images could be helpful in deciphering breast cancer phenotypes and may have potential as imaging biomarkers for prediction of breast cancer recurrence-free survival

Molecular population genetics and gene expression analysis of duplicated CBF genes of Arabidopsis thaliana

<p>Abstract</p> <p>Background</p> <p><it>CBF/DREB </it>duplicate genes are widely distributed in higher plants and encode transcriptional factors, or CBFs, which bind a DNA regulatory element and impart responsiveness to low temperatures and dehydration.</p> <p>Results</p> <p>We explored patterns of genetic variations of <it>CBF1, -2</it>, and -<it>3 </it>from 34 accessions of <it>Arabidopsis thaliana</it>. Molecular population genetic analyses of these genes indicated that <it>CBF2 </it>has much reduced nucleotide diversity in the transcriptional unit and promoter, suggesting that <it>CBF2 </it>has been subjected to a recent adaptive sweep, which agrees with reports of a regulatory protein of <it>CBF2</it>. Investigating the ratios of K_a/K_sbetween all paired <it>CBF </it>paralogus genes, high conservation of the AP2 domain was observed, and the major divergence of proteins was the result of relaxation in two regions within the transcriptional activation domain which was under positive selection after <it>CBF </it>duplication. With respect to the level of <it>CBF </it>gene expression, several mutated nucleotides in the promoters of <it>CBF3 </it>and <it>-1 </it>of specific ecotypes might be responsible for its consistently low expression.</p> <p>Conclusion</p> <p>We concluded from our data that important evolutionary changes in <it>CBF1, -2</it>, and -<it>3 </it>may have primarily occurred at the level of gene regulation as well as in protein function.</p