1,748 research outputs found

    Self-Excited Threshold Poisson Autoregression

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    This article studies theory and inference of an observation-driven model for time series of counts. It is assumed that the observations follow a Poisson distribution conditioned on an accompanying intensity process, which is equipped with a two-regime structure according to the magnitude of the lagged observations. Generalized from the Poisson autoregression, it allows more flexible, and even negative correlation, in the observations, which cannot be produced by the single-regime model. Classical Markov chain theory and Lyapunov’s method are used to derive the conditions under which the process has a unique invariant probability measure and to show a strong law of large numbers of the intensity process. Moreover, the asymptotic theory of the maximum likelihood estimates of the parameters is established. A simulation study and a real-data application are considered, where the model is applied to the number of major earthquakes in the world. Supplementary materials for this article are available online.postprin

    Gender Differences in Diabetes Attitudes and Adherence

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    This study focused on three questions: Is there a difference in men's and women's diabetes attitudes? Do health professionals give different recommendations to men and women? Is there a difference between men and women in care adherence? A total of 1201 patients with diabetes were surveyed; 65% of these patients were women. Differences in diabetes attitudes (three of seven attiticdes) were most evident between men and women with insulin-dependent diabetes mellitus (IDDM). No differences were found in the attitudes of men and women with non-insulin-dependent diabetes mellitus (NIDDM) using insulin, and only one attitude was different for patients with NIDDM not using insulin. Few differences were observed in the recommendations given by health professionals to men and women. Gender differences in adherence to the components of self-care also were minimal. These findings may indicate that there are many similarities in the reactions of men and women who have been diagnosed with diabetes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69143/2/10.1177_014572179502100605.pd

    The Relationship Between Diabetes-Related Attitudes and Patients' Self- Reported Adherence

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    This study involved 1202 patients who were placed into low adherence or high adherence groups based on their answers to questionnaires. The attitudes of each group were compared for a variety of adherence behaviors. Patients who reported high levels of adherence tended to have attitudes more in accord with diabetes experts. Members of the high adherence group strongly supported the need for special training for health care professionals who treat diabetes, favored team care, accepted the importance of patient compliance, acknowledged the seriousness of non-insulin-dependent diabetes mellitus (NIDDM), and recognized the relationship between glucose control and complications. Differences in attitudes between high- and low adherence groups were more prevalent for difficult adherence areas, eg, diet and exercise, than for easy adherence areas, eg, carrying sweets or diabetic identification. An understanding of patients' attitudes can help diabetes educators and patients develop realistic and relevant self-care plans.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68603/2/10.1177_014572179301900407.pd

    Dynamic Environmental Photosynthetic Imaging Reveals Emergent Phenotypes.

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    Understanding and improving the productivity and robustness of plant photosynthesis requires high-throughput phenotyping under environmental conditions that are relevant to the field. Here we demonstrate the dynamic environmental photosynthesis imager (DEPI), an experimental platform for integrated, continuous, and high-throughput measurements of photosynthetic parameters during plant growth under reproducible yet dynamic environmental conditions. Using parallel imagers obviates the need to move plants or sensors, reducing artifacts and allowing simultaneous measurement on large numbers of plants. As a result, DEPI can reveal phenotypes that are not evident under standard laboratory conditions but emerge under progressively more dynamic illumination. We show examples in mutants of Arabidopsis of such "emergent phenotypes" that are highly transient and heterogeneous, appearing in different leaves under different conditions and depending in complex ways on both environmental conditions and plant developmental age. These emergent phenotypes appear to be caused by a range of phenomena, suggesting that such previously unseen processes are critical for plant responses to dynamic environments

    Integrated problem-based learning in the neuroscience curriculum – the SUNY Downstate experience

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    BACKGROUND: This paper reports the author's initial experience as Block Director in converting a Conventional Curriculum into a problem-based learning model (PBL) for teaching Psychopathology. As part of a wide initiative in curriculum reform, Psychopathology, which was a six-week course in the second-year medical school curriculum, became integrated into a combined Neuroscience block. The study compares curriculum conversion at State University of New York (SUNY), Downstate, with the experiences at other medical centres that have instituted similar curricula reform. METHODS: Student satisfaction with the Conventional and PBL components of the Neuroscience curriculum was compared using questionnaires and formal discussions between faculty and a body of elected students. The PBL experience in Psychopathology was also compared with that of the rest of the Neuroscience Block, which used large student groups and expert facilitators, while the Psychopathology track was limited to small groups using mentors differing widely in levels of expertise. RESULTS: Students appeared to indicate a preference toward conventional lectures and large PBL groups using expert facilitators in contrast to small group mentors who were not experts. Small PBL groups with expert mentors in the Psychopathology track were also rated favorably. CONCLUSION: The study reviews the advantages and pitfalls of the PBL system when applied to a Neuroscience curriculum on early career development. At SUNY, conversion from a Conventional model to a PBL model diverged from that proposed by Howard S. Barrows where student groups define the learning objectives and problem-solving strategies. In our model, the learning objectives were faculty-driven. The critical issue for the students appeared to be the level of faculty expertise rather than group size. Expert mentors were rated more favorably by students in fulfilling the philosophical objectives of PBL. The author, by citing the experience at other major Medical Faculties, makes a cautious attempt to address the challenges involved in the conversion of a Psychopathology curriculum into a PBL dominated format

    SCOWLP classification: Structural comparison and analysis of protein binding regions

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    <p>Abstract</p> <p>Background</p> <p>Detailed information about protein interactions is critical for our understanding of the principles governing protein recognition mechanisms. The structures of many proteins have been experimentally determined in complex with different ligands bound either in the same or different binding regions. Thus, the structural interactome requires the development of tools to classify protein binding regions. A proper classification may provide a general view of the regions that a protein uses to bind others and also facilitate a detailed comparative analysis of the interacting information for specific protein binding regions at atomic level. Such classification might be of potential use for deciphering protein interaction networks, understanding protein function, rational engineering and design.</p> <p>Description</p> <p>Protein binding regions (PBRs) might be ideally described as well-defined separated regions that share no interacting residues one another. However, PBRs are often irregular, discontinuous and can share a wide range of interacting residues among them. The criteria to define an individual binding region can be often arbitrary and may differ from other binding regions within a protein family. Therefore, the rational behind protein interface classification should aim to fulfil the requirements of the analysis to be performed.</p> <p>We extract detailed interaction information of protein domains, peptides and interfacial solvent from the SCOWLP database and we classify the PBRs of each domain family. For this purpose, we define a similarity index based on the overlapping of interacting residues mapped in pair-wise structural alignments. We perform our classification with agglomerative hierarchical clustering using the complete-linkage method. Our classification is calculated at different similarity cut-offs to allow flexibility in the analysis of PBRs, feature especially interesting for those protein families with conflictive binding regions.</p> <p>The hierarchical classification of PBRs is implemented into the SCOWLP database and extends the SCOP classification with three additional family sub-levels: Binding Region, Interface and Contacting Domains. SCOWLP contains 9,334 binding regions distributed within 2,561 families. In 65% of the cases we observe families containing more than one binding region. Besides, 22% of the regions are forming complex with more than one different protein family.</p> <p>Conclusion</p> <p>The current SCOWLP classification and its web application represent a framework for the study of protein interfaces and comparative analysis of protein family binding regions. This comparison can be performed at atomic level and allows the user to study interactome conservation and variability. The new SCOWLP classification may be of great utility for reconstruction of protein complexes, understanding protein networks and ligand design. SCOWLP will be updated with every SCOP release. The web application is available at <url>http://www.scowlp.org</url>.</p

    Evaluation of an Activated Patient Diabetes Education Newsletter

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    This study evaluated a monthly; activated patient newsletter sent to over 7000 patients in Michigan with diabetes. The newsletter provided concise and action-oriented information about diabetes care. Patients who had signed up to receive the newsletter during the first 4 months of the project (1863) were surveyed to determine how many patients found the newsletter helpful; 80% (1498) of the patients replied. Patients who found the newsletter most helpful were older, had lower incomes, and reported more corrtplications, less understanding of diabetes, and being in poorer overall health. They also were more likely to have non-insulin-dependent diabetes mellitus (NIDDM) than insulin-dependent diabetes mellitus (IDDM). We concluded that the activated patient newsletter is a useful public health/patient education intervention for persons with diabetes. Such a newsletter should be part of a coordinated system of ongoing patient care, education, screening, and social and psychological support.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68904/2/10.1177_014572179402000106.pd

    Tutoring in problem-based learning medical curricula: the influence of tutor background and style on effectiveness

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    BACKGROUND: Evidence for the superiority of particular characteristics in PBL tutors in medical curricula is generally inconclusive. Most studies have investigated the effectiveness of content experts compared with that of non-experts as measured either by student satisfaction or academic achievement. A few have compared academic staff tutors with student tutors. The purpose of this study was to investigate the relationship between students' perception of overall tutor effectiveness, particular tutor behaviours, clinical qualifications and academic appointment. METHOD: A questionnaire designed to evaluate particular aspects of PBL tutoring technique, related either to subject-matter knowledge or to process-facilitation skill, as well as overall effectiveness, was distributed to students in first year of a PBL medical program at the end of each of three tutor terms. A total of 76 tutor terms were included in the study. Data analysis compared clinical with non-clinical tutors, and staff with non-staff tutors. RESULTS: Clinically qualified tutors used their subject-matter knowledge significantly more than non-clinical tutors and were seen as being more empathic with their students. Staff tutors placed more emphasis on assessment than non-staff tutors and were seen as having greater skill in establishing and maintaining an environment of cooperation within their PBL groups than non-staff tutors. CONCLUSION: These results suggest that both subject-matter knowledge and process-facilitation skills are necessary but not individually sufficient characteristics of effective tutors

    The Yeast Resource Center Public Image Repository: A large database of fluorescence microscopy images

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    <p>Abstract</p> <p>Background</p> <p>There is increasing interest in the development of computational methods to analyze fluorescent microscopy images and enable automated large-scale analysis of the subcellular localization of proteins. Determining the subcellular localization is an integral part of identifying a protein's function, and the application of bioinformatics to this problem provides a valuable tool for the annotation of proteomes. Training and validating algorithms used in image analysis research typically rely on large sets of image data, and would benefit from a large, well-annotated and highly-available database of images and associated metadata.</p> <p>Description</p> <p>The Yeast Resource Center Public Image Repository (YRC PIR) is a large database of images depicting the subcellular localization and colocalization of proteins. Designed especially for computational biologists who need large numbers of images, the YRC PIR contains 532,182 TIFF images from nearly 85,000 separate experiments and their associated experimental data. All images and associated data are searchable, and the results browsable, through an intuitive web interface. Search results, experiments, individual images or the entire dataset may be downloaded as standards-compliant OME-TIFF data.</p> <p>Conclusions</p> <p>The YRC PIR is a powerful resource for researchers to find, view, and download many images and associated metadata depicting the subcellular localization and colocalization of proteins, or classes of proteins, in a standards-compliant format. The YRC PIR is freely available at <url>http://images.yeastrc.org/</url>.</p

    A case report of bilateral synovial chondromatosis of the ankle

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    <p>Abstract</p> <p>Background</p> <p>Synovial chondromatosis is a rare, generally benign condition which affects synovial membranes. It most commonly involves large joints such as the knee, hip, and elbow, but its presence in smaller joints has also been reported. The diagnosis of synovial chondromatosis is commonly made following a thorough history, physical examination, and radiographic examination. Patients may report pain and swelling within a joint which is often aggravated with physical activity.</p> <p>Case presentation</p> <p>A rare case of bilateral synovial chondromatosis of the ankle is reviewed. A 26 year-old male presented with chronic bilateral ankle pain. Physical examination suggested and imaging confirmed multiple synovial chondromatoses bilaterally, likely secondary to previous trauma.</p> <p>Conclusion</p> <p>The clinical and imaging findings, along with potential differential diagnoses, are described. Since this condition tends to be progressive but self-limiting, indications for surgery depend on the level of symptomatic presentation in addition to the functional demands of the patient. Following a surgical consultation, it was decided that it was not appropriate to pursue surgery at the present time.</p
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