Linking engagement and performance: The social network analysis perspective

Theories developed by Tinto and Nora identify academic performance, learning gains, and involvement in learning communities as significant facets of student engagement that, in turn, support student persistence. Collaborative learning environments, such as those employed in the Modeling Instruction introductory physics course, provide structure for student engagement by encouraging peer-to-peer interactions. Because of the inherently social nature of collaborative learning, we examine student interactions in the classroom using network analysis. We use centrality---a family of measures that quantify how connected or "central" a particular student is within the classroom network---to study student engagement longitudinally. Bootstrapped linear regression modeling shows that students' centrality predicts future academic performance over and above prior GPA for three out of four centrality measures tested. In particular, we find that closeness centrality explains 28 % more of the variance than prior GPA alone. These results confirm that student engagement in the classroom is critical to supporting academic performance. Furthermore, we find that this relationship for social interactions does not emerge until the second half of the semester, suggesting that classroom community develops over time in a meaningful way

Photometric Decomposition of Barred Galaxies

We present a non-parametric method for decomposition of the light of disk galaxies into disk, bulge and bar components. We have developed and tested the method on a sample of 68 disk galaxies for which we have acquired I-band photometry. The separation of disk and bar light relies on the single assumption that the bar is a straight feature with a different ellipticity and position angle from that of the projected disk. We here present the basic method, but recognise that it can be significantly refined. We identify bars in only 47% of the more nearly face-on galaxies in our sample. The fraction of light in the bar has a broad range from 1.3% to 40% of the total galaxy light. If low-luminosity galaxies have more dominant halos, and if halos contribute to bar stability, the luminosity functions of barred and unbarred galaxies should differ markedly; while our sample is small, we find only a slight difference of low significance.Comment: Accepted to appear in AJ, 36 pages, 9 figures, full on-line figures available at http://www.physics.rutgers.edu/~sellwood/Reese.htm

Non-invasive neurosensory testing used to diagnose and confirm successful surgical management of lower extremity deep distal posterior compartment syndrome

<p>Abstract</p> <p>Background</p> <p>Chronic exertional compartment syndrome (CECS) is characterized by elevated pressures within a closed space of an extremity muscular compartment, causing pain and/or disability by impairing the neuromuscular function of the involved compartment. The diagnosis of CECS is primarily made on careful history and physical exam. The gold standard test to confirm the diagnosis of CECS is invasive intra-compartmental pressure measurements. Sensory nerve function is often diminished during symptomatic periods of CECS. Sensory nerve function can be documented with the use of non-painful, non-invasive neurosensory testing.</p> <p>Methods</p> <p>Non-painful neurosensory testing of the myelinated large sensory nerve fibers of the lower extremity were obtained with the Pressure Specified Sensory Device™ in a 25 year old male with history and invasive compartment pressures consistent with CECS both before and after running on a tread mill. After the patient's first operation to release the deep distal posterior compartment, the patient failed to improve. Repeat sensory testing revealed continued change in his function with exercise. He was returned to the operating room where a repeat procedure revealed that the deep posterior compartment was not completely released due to an unusual anatomic variant, and therefore complete release was accomplished.</p> <p>Results</p> <p>The patient's symptoms numbness in the plantar foot and pain in the distal calf improved after this procedure and his repeat sensory testing performed before and after running on the treadmill documented this improvement.</p> <p>Conclusion</p> <p>This case report illustrates the principal that non-invasive neurosensory testing can detect reversible changes in sensory nerve function after a provocative test and may be a helpful non-invasive technique to managing difficult cases of persistent lower extremity symptoms after failed decompressive fasciotomies for CECS. It can easily be performed before and after exercise and be repeated at multiple intervals without patient dissatisfaction. It is especially helpful when other traditional testing has failed.</p

Identifying missing dictionary entries with frequency-conserving context models

In an effort to better understand meaning from natural language texts, we explore methods aimed at organizing lexical objects into contexts. A number of these methods for organization fall into a family defined by word ordering. Unlike demographic or spatial partitions of data, these collocation models are of special importance for their universal applicability. While we are interested here in text and have framed our treatment appropriately, our work is potentially applicable to other areas of research (e.g., speech, genomics, and mobility patterns) where one has ordered categorical data (e.g., sounds, genes, and locations). Our approach focuses on the phrase (whether word or larger) as the primary meaning-bearing lexical unit and object of study. To do so, we employ our previously developed framework for generating word-conserving phrase-frequency data. Upon training our model with the Wiktionary, an extensive, online, collaborative, and open-source dictionary that contains over 100000 phrasal definitions, we develop highly effective filters for the identification of meaningful, missing phrase entries. With our predictions we then engage the editorial community of the Wiktionary and propose short lists of potential missing entries for definition, developing a breakthrough, lexical extraction technique and expanding our knowledge of the defined English lexicon of phrases

Temperature Assessment on a Reclaimed Surface Mine During Northern Bobwhite Breeding Season: Considerations for Habitat Management

Ground-level air temperatures were assessed within 4 distinct habitat areas on a managed reclaimed surface mine at Peabody Wildlife Management Area, Kentucky, 26 June–17 July 2015, during the northern bobwhite (Colinus virginianus) brood season. Habitat consisted of disked and nondisked areas of native grass and an invasive species, sericea lespedeza (Lespedeza cuneata). Disked areas offered more open space for bobwhite mobility and experienced higher average temperatures than nondisked sites. Although statistically significant, differences in air temperature between disked and nondisked areas were likely too small to have practical implications for bobwhite habitat management in Kentucky under current climatic conditions. This will likely change in the future as the regional climate warms and periods of excessive heat are more likely to occur. Consequently, managers may want to consider microclimate when making management decisions

Ethnic differences in the prevalence of inherited thrombophilic polymorphisms in an asymptomatic Australian prenatal population

Differences in the prevalence of thrombophilias in different ethnic populations have been demonstrated. Because the Australian population includes many different ethnic groups, we sought to assess the effect of ethnicity in our Australian prenatal population on the prevalence of thrombophilic polymorphisms. Asymptomatic, nulliparous women (n = 1,129) recruited for a large prospective study were included in this analysis. These women had no personal or family history of venous thromboembolism and were not known to be carrying an inherited or acquired thrombophilia. Ethnicity was determined at recruitment, and women were categorized as being of Northern European, Southern European, Middle Eastern, Asian, or Other ethnicity. These women underwent genotyping for the following polymorphisms: factor V Leiden G1691A, prothrombin gene A20210G mutation, methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, and thrombomodulin C1418T. The factor V Leiden allele was seen significantly more frequently in patients of Middle Eastern background compared to those of Northern European and Asian ethnicity (p < 0.05). The prothrombin gene mutation was seen significantly more frequently in patients of Southern European ethnicity compared to those of Northern European or Asian ethnicity (p < 0.05). The MTHFR C677T allele (mutant) was significantly less common in those of Asian ethnicity compared to patients of Northern European and Southern European ethnicity (p < 0.0005). There were no significant differences seen with the MTHFR A1298C polymorphism. The mutant thrombomodulin allele was seen significantly more frequently in Asian women compared to Northern European, Southern European, or Middle Eastern women (p < 0.005). There are important ethnic differences in the prevalence of thrombophilic polymorphisms in the Australian prenatal population

Natural Products as Therapeutic Agents in Cancer Treatment

Cancer accounts for 25% of deaths in the United States, and brain tumors greatly contribute to this percentage. However, relative to other types of cancers, brain tumors prove difficult to treat because they are heterogeneous, highly proliferative, highly invasive, and resistant to the traditional cancer treatments of chemotherapy and radiotherapy. Past studies have shown that flavonoids and curcuminoids, two classes of compounds derived from natural sources, are effective in inhibiting the development and metastasis of breast and lung cancer cells. Research has also indicated that these compounds have potential for treating brain tumors. The purpose of this research is to further explore the potential of flavonoids as therapeutic options for the treatment of brain tumors. Specifically, flavonoids’ effect on cell proliferation, cell death, and tumor invasion will be studied. Another objective of this study is to identify the signaling mechanism by which flavonoids mediate their therapeutic effects on brain tumor cell lines. Three human brain tumor cell lines (U-1242, U-251, and U-87) will be studied. They will be treated with various flavonoids at increasing concentrations (10, 20, 40, and 80 µM). Cells will be counted following the trypan blue staining protocol. MTT assays and Western blot analyses will be used to assess cell proliferation. Cell death will be assessed with flow analyses and Western blot analyses. Unpaired t-tests will be run to compare treated and control cells at a 95% confidence interval. If necessary, one-way ANOVA with multiple comparisons will be used to compare multiple treatment groups and a control at a 95% confidence interval, and the Tukey post-hoc test will be utilized if appropriate. All statistical tests will be run in IBM SPSS 21®