12,876 research outputs found
The Hetu'u Global Network: Measuring the Distance to the Sun Using the June 5th/6th Transit of Venus
In the spirit of historic astronomical endeavors, we invited school groups
across the globe to collaborate in a solar distance measurement using the rare
June 5/6th transit of Venus. In total, we recruited 19 school groups spread
over 6 continents and 10 countries to participate in our Hetu'u Global Network.
Applying the methods of French astronomer Joseph-Nicolas Delisle, we used
individual second and third Venus-Sun contact times to calculate the distance
to the Sun. Ten of the sites in our network had amiable weather; 8 of which
measured second contact and 5 of which measured third contact leading to
consistent solar distance measurements of 152+/-30 million km and 163+/-30
million km respectively. The distance to the Sun at the time of the transit was
152.25 million km; therefore, our measurements are also consistent within
1sigma of the known value. The goal of our international school group network
was to inspire the next generation of scientists using the excitement and
accessibility of a rare astronomical event. In the process, we connected
hundreds of participating students representing a diverse, multi-cultural group
with differing political, economic, and racial backgrounds.Comment: 19 pages; 7 Figures; 1 Table; Accepted for publication in Astronomy
Education Review (AER) For more information see
http://www.das.uchile.cl/~drodrigu/easter/index_en.htm
What Is The Impact Of Collaborative Exams On Learning And Attitudes In Introductory Astronomy Classes?
We present results of a two-semester study to gauge the impact of collaborative two-stage exams on student learning and attitudes in university-level introductory astronomy classes for non-science majors. In the collaborative two-stage exam setting, students first completed an exam individually, and then they reconsidered a subset of exam questions within their previously established groups, discussing the questions with their peers to arrive at a common answer.Students took three to four exams during the semester using this format. At mid-semester, we surveyed the students to gauge their attitudes about collaborative work and its perceived influence on their exam preparation and performance. At the end of the semester, students sat an individual-only final exam, which contained all previous collaborative-phase questions, as well as a subset of questions seen only on the individual portions of the exams. When we compare the normalized gain on final exam questions that were included in the collaborative portions to that on questions found in only the individual portions, we find higher normalized gains in general for questions encountered on the collaborative portions of the exams. These gains are accompanied by a statistically significant effect size (Cohenâs d). We note, however, that this improved performance appears to be dependent upon several factors. Those factors might include diminished retention over time, the assessment of overly complex concepts, and concept saturation. Our mid-semester survey indicates that the collaborative experience appears have a positive influence on their overall attitudes and their study habits
Crystallization of BiâSrâCaâCuâO glasses in oxygen
A detailed study of the crystallization process for compositions near Bi2Sr2Ca1Cu2Oy was undertaken using differential thermal analysis (DTA), transmission and scanning electron microscopy (TEM and SEM), and x-ray diffraction (XRD). Glasses prepared by a splat-quench technique were free of secondary phases in most cases. A two-step crystallization process in oxygen was observed in which partial crystallization of the glass occurs initially with the nucleation of â2201â and Cu2O, and is completed with the formation of SrO, CaO, and Bi2Sr3âxCaxOy. No specific thermal event could be associated with the formation of the â2212â phase. Rather, formation occurs via conversion of 2201 into 2212. This was a kinetically limited process at temperatures below 800 °C as other phases were found to evolve in addition to the 2212 phase during extended anneals. In contrast, a nearly full conversion to the 2212 phase occurred after only 1 min of annealing at 800 °C and above. However, changes in resistivity data, secondary phases, and the measured 2212 composition upon extended anneals at 865 °C showed that considerably longer heat treatments were necessary for the sample to reach its equilibrium state
Injustice perceptions about pain: parentâchild discordance is associated with worse functional outcomes
Pain is experienced within and influenced by social environments. For children with chronic pain, the childâparent relationship and parental beliefs about pain are particularly important and may influence pain outcomes. Pain-related injustice perceptions have recently been identified as an important cognitiveâemotional factor for children with pain. The current study aimed to better understand the pain-related injustice perceptions of children with chronic pain and their parents. The sample consisted of 253 pediatric chronic pain patients (mean age = 14.1 years, 74% female) presenting to a tertiary pain clinic. Patients completed measures of pain intensity, pain-related injustice perceptions, stress, functional disability, and quality of life. Parents completed a measure of pain-related injustice perceptions about their child's pain. Childâparent dyads were categorized into 1 of 4 categories based on the degree of concordance or discordance between their scores on the injustice measures. One-way analysis of variances examined differences in pain intensity, stress, functional disability, and quality of life across the 4 dyad categories. Our findings indicated that both the degree (concordant vs discordant) and direction (discordant low childâhigh parent vs discordant high childâlow parent) of similarity between child and parent injustice perceptions were associated with child-reported pain intensity, stress, functional disability, and quality of life. The poorest outcomes were reported when children considered their pain as highly unjust, but their parents did not. These findings highlight the important role of parents in the context of pain-related injustice perceptions in pediatric chronic pain
Long-term effect of antiepileptic drug switch on serum lipids and C-reactive protein.
BACKGROUND: Prior studies have shown that switching patients from inducing antiepileptic drugs (AEDs) to lamotrigine, levetiracetam, or topiramate reduces serum lipids and C-reactive protein (CRP). These studies were all of short duration, and some drugs, such as zonisamide, have not been investigated.
METHODS: We recruited 41 patients taking phenytoin or carbamazepine who were being switched to zonisamide, lamotrigine, or levetiracetam. We measured serum lipids and CRP before the switch, \u3e6weeks after, and \u3e6months after. An untreated control group (n=14) underwent similar measurement. We combined these data with those of our previous investigation (n=34 patients and 16 controls) of a very similar design.
RESULTS: There were no differences in outcome measures between the two inducing AEDs nor among the three noninducing AEDs. Total cholesterol (TC), atherogenic lipids, and CRP were higher under inducer treatment than in controls. All measures were elevated under inducer treatment relative to noninducer treatment, including TC (24mg/dL higher, 95% CI: 17.5-29.9, p
CONCLUSIONS: We demonstrate that switching from inducing to noninducing AEDs produces an enduring reduction in serum lipids and CRP. These results provide further evidence that inducing AEDs may be associated with elevated vascular disease risk. These are the first vascular risk marker data in patients taking zonisamide, which shows a profile similar to that of other noninducing AEDs
Rural Community College Student Perceptions of Barriers to College Enrollment
Rural community college students face unique difficulties in higher education for many reasons, including the resources they typically have access to, their collective histories, and in many cases, the preparation they received in high school. These challenges might be low-performing secondary schools, a lack of tradition and precedence in attending college, and even limited technology connectivity. These difficulties can be seen as barriers to college attendance, and it is important to understand how rural community college students see these barriers, and even more important to understand how they can be overcome. The current study sought to take the first step in understanding what inhibits college student enrollment by exploring self-reported barriers to community college matriculation. Using two case study institutions and a modified survey instrument, results largely supported existing research in that preparation for postsecondary education and finances were critical in deciding whether or not to enroll in the community college. Additionally, parental enrollment in higher education was perceived to play a role in attending college, validating the growing literature base on college attendance, in general, and rural students in particular. Somewhat contradictory to the literature of rural education, however, was the finding that technology connectivity was not seen as a barrier to education
Spectral mapping of brain functional connectivity from diffusion imaging.
Understanding the relationship between the dynamics of neural processes and the anatomical substrate of the brain is a central question in neuroscience. On the one hand, modern neuroimaging technologies, such as diffusion tensor imaging, can be used to construct structural graphs representing the architecture of white matter streamlines linking cortical and subcortical structures. On the other hand, temporal patterns of neural activity can be used to construct functional graphs representing temporal correlations between brain regions. Although some studies provide evidence that whole-brain functional connectivity is shaped by the underlying anatomy, the observed relationship between function and structure is weak, and the rules by which anatomy constrains brain dynamics remain elusive. In this article, we introduce a methodology to map the functional connectivity of a subject at rest from his or her structural graph. Using our methodology, we are able to systematically account for the role of structural walks in the formation of functional correlations. Furthermore, in our empirical evaluations, we observe that the eigenmodes of the mapped functional connectivity are associated with activity patterns associated with different cognitive systems
Perceived Injustice Is Associated With Pain and Functional Outcomes in Children and Adolescents With Chronic Pain: A Preliminary Examination
Chronic pain is prevalent in children/adolescents and contributes to high rates of healthcare utilization. Research suggests injustice perceptions about pain are important in adult patients and a possible treatment focus. We conducted a preliminary evaluation of the psychometric properties of the Injustice Experiences Questionnaire (IEQ) and the relationship between injustice perceptions, pain, and functioning in chronic pain patients (N = 139, mean age = 15 years, 72% female) presenting to a pediatric pain clinic. Patients completed measures assessing pain intensity, injustice perceptions about pain, catastrophizing, overall functional disability, emotional functioning, social functioning, and school functioning. The IEQ showed good reliability and validity. Higher levels of perceived injustice were associated with higher levels of pain intensity, catastrophizing, and functional disability, and with poorer emotional, social, and school functioning. Additionally, perceived injustice remained significantly associated with pain intensity, functional disability, emotional functioning, social functioning, and school functioning after accounting for relevant demographic and clinical factors. This is the first study to suggest that injustice perceptions are important in the experience of pediatric chronic pain patients. Future studies should more thoroughly examine the psychometric properties of the IEQ in children/adolescents and elucidate the causal nature of these relationships, which will inform treatment efforts to improve pediatric pain care.
Perspective
This initial investigation suggests that injustice perceptions about pain can be reliably and validly measured and are tied to important clinical outcomes in children/adolescents. Future studies that replicate and extend these preliminary results are necessary to determine the extent to which injustice perceptions are an important target for intervention
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