957 research outputs found
Lower critical field measurements in YBa2Cu3O(6+x) single crystals
The temperature dependence of the lower critical field in YBa2Cu3O(6+x) single crystals was determined by magnetization measurements with the applied field parallel and perpendicular to the c-axis. Results are compared with data from the literature and fitted to Ginzberg-Landau equations by assuming a linear dependence of the parameter kappa on temperature. A value of 7 plus or minus 2 kOe was estimated for the thermodynamic critical field at T = O by comparison of calculated H (sub c2) values with experimental data from the literature
Measurement of H(sub c1) in a single crystal of YBa2Cu3O7 with low pinning
The measurement of H(sub c1) in barium yttrium copper oxide (BYCO) is often ambiguous because the presence of large pinning forces makes it difficult to discern exactly where the first deviation from linearity occurs. In addition there are complications because demagnetizing factors are often not well known. By utilizing a single crystal of YBCO with a nearly cubic shape, the uncertainty in the demagnetizing factor was minimized. In addition, the crystal used exhibited a very small amount of pinning with H applied perpendicular to the c axis, and a sharp break in the initial magnetization vs. field curve could be observed over a wide range of temperature. This allowed a precise determination of H(sub c1). The measured values of H(sub c1) could be well described by the Abrikosov relation with a Ginzburg-Landau parameter which varied linearly with temperature
Couplet scoring for research based assessment instruments
Contemporary content-focused research-based assessment instruments typically
use instrument items (i.e., questions) as the unit of assessment for instrument
scoring, reporting, and validation. However, traditional item-based scoring has
a number of limitations, including several arising from the use of the common
assessment development conventions of single-construct items,
unidimensionality, and single-correct-answer items. Couplet scoring, introduced
in this paper, employs the couplet as an alternative unit of assessment, where
a couplet is essentially an item viewed and scored through the lens of a
specific assessment objective (AO). With couplet scoring, a single item may
have more than one AO and therefore more than one couplet. In this paper, we
outline the limitations of traditional item scoring, introduce couplet scoring
and discuss its affordances (especially as they relate to limitations of item
scoring), and use a recently developed content RBAI to ground our discussion.Comment: 13 pages, 2 figure
Mortality in non-exacerbating COPD: a longitudinal analysis of UK primary care data
Introduction: Non-exacerbating patients with chronic obstructive pulmonary disease (COPD) are a less studied phenotype. We investigated clinical characteristics, mortality rates and causes of death among non-exacerbating compared with exacerbating patients with COPD. Methods: We used data from the Clinical Practice Research Datalink, Hospital Episode Statistics and Office for National Statistics between 1 January 2004 and 31 December 2018. Ever smokers with a COPD diagnosis with minimum 3 years of baseline information were included. We compared overall using Cox regression and cause-specific mortality rates using competing risk analysis, adjusted for age, sex, deprivation, smoking status, body mass index, GOLD stage and comorbidities. Causes of death were identified using International Classification of Diseases-10 codes. Results: Among 67 516 patients, 17.3% did not exacerbate during the 3-year baseline period. Mean follow-up was 4 years. Non-exacerbators were more likely to be male (63.3% vs 52.4%, p<0.001) and less often had a history of asthma (33.9% vs 43.6%, p<0.001) or FEV1<50% predicted (23.7 vs 31.8%) compared with exacerbators. Adjusted HR for overall mortality in non-exacerbators compared with exacerbators was 0.62 (95% CI 0.56 to 0.70) in the first year of follow-up and 0.87 (95% CI 0.83 to 0.91) thereafter. Non-exacerbating patients with COPD died less of respiratory causes than exacerbators (29.2% vs 40.3%) and more of malignancies (29.4% vs 23.4%) and cardiovascular diseases (26.2% vs 22.9%). HRs for malignant and circulatory causes of death were increased after the first year of follow-up. Discussion: In this primary care cohort, non-exacerbators showed distinct clinical characteristics and lower mortality rates. Non-exacerbators were equally likely to die of respiratory, malignant or cardiovascular diseases
Seasonal Distribution and Movements of Shortnose Sturgeon and Atlantic Sturgeon in the Penobscot River Estuary, Maine
Relatively little is known about the distribution and seasonal movement patterns of shortnose sturgeon Acipenser brevirostrum and Atlantic sturgeon Acipenser oxyrinchus oxyrinchus occupying rivers in the northern part of their range. During 2006 and 2007, 40 shortnose sturgeon (66-113.4 cm fork length [FL]) and 8 Atlantic sturgeon (76.2-166.2 cm FL) were captured in the Penobscot River, Maine, implanted with acoustic transmitters, and monitored using an array of acoustic receivers in the Penobscot River estuary and Penobscot Bay. Shortnose sturgeon were present year round in the estuary and overwintered from fall (mid-October) to spring (mid-April) in the upper estuary. In early spring, all individuals moved downstream to the middle estuary. Over the course of the summer, many individuals moved upstream to approximately 2 km of the downstream-most dam (46 river kilometers [rkm] from the Penobscot River mouth [rkm 0]) by August. Most aggregated into an overwintering site (rkm 36.5) in mid-to late fall. As many as 50% of the tagged shortnose sturgeon moved into and out of the Penobscot River system during 2007, and 83% were subsequently detected by an acoustic array in the Kennebec River, located 150 km from the Penobscot River estuary. Atlantic sturgeon moved into the estuary from the ocean in the summer and concentrated into a 1.5-km reach. All Atlantic sturgeon moved to the ocean by fall, and two of these were detected in the Kennebec River. Although these behaviors are common for Atlantic sturgeon, regular coastal migrations of shortnose sturgeon have not been documented previously in this region. These results have important implications for future dam removals as well as for rangewide and river-specific shortnose sturgeon management
KAJIAN KEBUTUHAN INTEGRASI LAYANAN ANGKUTAN UMUM MASSAL DI KOTA SEMARANG DAN SEKITARNYA
Angkutan umum massal berbasis jalan telah dikembangkan oleh Pemerintah Kota Semarang sejak tahun 2009 hingga kini (Trans Semarang). Disisi lain, Pemerintah Provinsi Jawa Tengah sejak tahun 2017 juga melakukan hal yang sama di Wilayah Aglomerasi Kedungsepur (Trans Jateng). Namun terkesan berjalan sendiri-sendiri dan terjadi tumpang tindih layanan di ruas-ruas jalan tertentu. Dengan demikian, perlu dilakukan penelitian kebutuhan pengintegrasian layanan angkutan umum massal di Kota Semarang dan sekitarnya. Penelitian ini menggunakan pendekatan kuantitatif dengan analisis statistik deskriptif dan analisis spasial untuk mengetahui karakteristik dan pola permintaan perjalanan penggunanya. Hasil penelitian ini menunjukkan bahwa pengguna Koridor 1 dan 2 Trans Semarang dari luar Kota Semarang mencapai 39,14% dan 60,86% berasal dari dalam Kota Semarang. Pengguna dengan tujuan ke luar Kota Semarang mencapai 42,23% dan 57,77% tujuan di dalam Kota Semarang. Hal ini membuktikan bahwa Koridor 1 dan 2 mengakomodasi penumpang yang asal tujuannya cukup besar dari luar Kota Semarang. Terdapat tumpang tindih layanan mencapai 60% dari panjang lintasan di Koridor 1 Trans Jateng dan Koridor 2 Trans Semarang. Moda first mile pengguna Koridor 2 didominasi oleh Trans Jateng sebesar 51,51% dan last mile didominasi oleh penggunaan motor sebesar 48,10%. Penelitian ini menyarankan bahwa rute layanan Trans Jateng kedepannya dapat mengakomodir permintaan perjalanan di dalam kawasan penyangga dengan konsep layanan loop (mengelilingi), berbeda dari kondisi saat ini. Selanjutnya, layanan Trans Jateng yang menuju ke Kota Semarang dapat berhenti di titik perbatasan, dimana pergerakan kemudian dilayani oleh Trans Semarang dan diharapkan dapat memberikan layanan yang lebih baik kepada masyarakat di Kota Semarang dan sekitarnya.
Threading, Stitching, and Storytelling: Using CBPR and Blackfoot Knowledge and Cultural Practices to Improve Domestic Violence Services for Indigenous Women
This article discusses a community-based participatory research (CBPR) project at two womenâs emergency shelters in rural southwestern Alberta. The CBPR project aimed to improve shelter services on and off reserve in our area by engaging the voices of Indigenous women who had experienced domestic violence. The projectâs methods were participatory appraisal and arts-based work re-imagined through Blackfoot cultural practices of storytelling and shawl making. The project created a rare safe space where thirteen Blackfoot women emphasised DV services should provide opportunities to connect with family and community and role model Blackfoot knowledge. Role modelling traditional knowledges aids developing life and parenting skills, opening up pathways for Indigenous women to more positive, secure futures. These womenâs recommendations impelled this article to challenge the individualized case management model and discourses of cultural competence dominating Canadian DV services, which isolate and marginalize Indigenous women when they seek help. We highlight resources existing in Blackfoot communities to manage and prevent violence by protecting and facilitating Indigenous womenâs connections to their communities and cultures, and offer ways to utilize these more effectively in service settings
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Self-assembly, nematic phase formation and organocatalytic behaviour of a proline-functionalized lipopeptide
The self-assembly of the amphiphilic lipopeptide PAEPKI-C16 (P = proline, A = alanine, E = glutamic acid, K = lysine, I = isoleucine, C16 = hexadecyl) was investigated using a combination of spectroscopic, microscopic and scattering methods and compared to C16-IKPEAP with the same (reversed) peptide sequence and the alkyl chain positioned N-terminally and which lacks a free N-terminal proline residue. The catalytic activity of these peptides were then compared using a model aldol reaction system. For PAEPKI-C16, Cryo-TEM images showed the formation of micrometer length fibers, which by Small-angle X-ray scattering (SAXS) were found to have a radius of 2.5 - 2.6 nm. Spectroscopic analysis shows these fibers are built from -sheets. This behaviour is in complete contrast to that of C16-IKPEAP which forms spherical micelles with peptides in a disordered conformation [Hutchinson, J. A. et al. J. Phys. Chem. B 2019, 123, 613]. For PAEPKI-C16, the spontaneous alignment of fibers was observed upon increasing pH, which was accompanied by observed birefringence and anisotropy of SAXS patterns. This shows the formation of a nematic liquids and unprecedented nematic hydrogel formation was also observed these lipopeptides at sufficiently high concentrations. SAXS shows retention of an ultrafine (1.7 nm core radius) fibrillar network within the hydrogel. PAEPKI-C16 with free N-terminal proline shows enhanced anti:syn diastereoselectivity and better conversion compared to C16-IKPEAP. The cytotoxicity of PAEPKI-C16 was also lower than C16-IKPEAP for both fibroblast and cancer cell lines. These results highlight the sensitivity of lipopeptide properties to the presence of a free proline residue. The spontaneous nematic phase formation by PAEPKI-C16 points to the highly anisotropy of its ultrafine fibrillar structure and the formation of such a phase at low concentration in aqueous solution may be valuable for future applications
Survey of physics reasoning on uncertainty concepts in experiments: an assessment of measurement uncertainty for introductory physics labs
Measurement uncertainty is a critical feature of experimental research in the
physical sciences, and the concepts and practices surrounding measurement
uncertainty are important components of physics lab courses. However, there has
not been a broadly applicable, research-based assessment tool that allows
physics instructors to easily measure students' knowledge of measurement
uncertainty concepts and practices. To address this need, we employed
Evidence-Centered Design to create the Survey of Physics Reasoning on
Uncertainty Concepts in Experiments (SPRUCE). SPRUCE is a pre-post assessment
instrument intended for use in introductory (first- and second-year) physics
lab courses to help instructors and researchers identify student strengths and
challenges with measurement uncertainty. In this paper, we discuss the
development of SPRUCE's assessment items guided by Evidence-Centered Design,
focusing on how instructors' and researchers' assessment priorities were
incorporated into the assessment items and how students' reasoning from pilot
testing informed decisions around item answer options.Comment: 23 pages, 11 figures, submitted as part of the Physical Review
Physics Education Research Focused Collection on Instructional Labs:
Improving Traditions and New Direction
Autism and the U.K. secondary school experience
This research investigated the self-reported mainstream school experiences of those diagnosed on the autistic spectrum compared with the typically developing school population. Existing literature identifies four key areas that affect the quality of the school experience for students with autism: social skills, perceived relationships with teaching staff, general school functioning, and interpersonal strengths of the young person. These areas were explored in a mainstream U.K. secondary school with 14 students with autism and 14 age and gender matched students without autism, using self-report questionnaires and semi-structured interviews. Quantitative analyses showed consistent school experiences for both groups, although content analysis of interview data highlighted some differences in the ways in which the groups perceive group work, peers, and teaching staff within school. Implications for school inclusion are discussed, drawing attention to how staff awareness of autism could improve school experience and success for students with autism attending mainstream schools
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