Effects of noise on hysteresis and resonance width in graphene and nanotubes resonators

We investigate the role that noise plays in the hysteretic dynamics of a suspended nanotube or a graphene sheet subject to an oscillating force. We find that not only the size but also the position of the hysteresis region in these systems can be controlled by noise. We also find that nano-resonators act as noise rectifiers: by increasing the noise in the setup, the resonance width of the characteristic peak in these systems is reduced and, as a result, the quality factor is increased.Comment: 15 pages, 6 figures. Sent to PRB (in revision

Kajian Keprihatinan Ahli Akademik Terhadap Tatacara Berpakaian, Sahsiah dan Rupa Diri Pelajar Universiti Malaysia Pahang

Tamadun adalah perkataan Arab “Maddana” yang bermaksud adab, akhlaq, moral dan mempunyai agama yang baik. Manakala hidup bertamadun bermaksud kehidupan yang penuh dengan adab sopan, moral dan berakhlak. Dalam konteks dunia pendidikan hari ini isu tatacara berpakaian, rupa diri, sahsiah dan akhlak pelajar pernah dibincangkan dan diketengahkan di peringkat institusi pengajian tinggi amnya, namun masih tidak menampakkan hasil positif. Kelihatan seolah-olah tiada keseriusan daripada pelbagai pihak untuk mengendalikan dan menjayakan isu ini sebaik mungkin sehingga ke akar umbinya dan secara tidak langsung untuk berusaha menyelesaikannya. Justeru, satu kajian berfokus telah dijalankan terhadap pelajar di Universiti Malaysia Pahang dari pelbagai fakulti. Kajian ini bertujuan meninjau sejauh mana komitmen pensyarah selaku aset penting yang berintegriti tinggi, bernilai dan berakhlak mulia dalam menjalankan amanah mereka mendidik anak bangsa khususnya dalam membangunkan akhlak dan sahsiah diri terpuji dalam kalangan mahasiswa. Kajian ini dilakukan secara tinjauan melalui aplikasi internet iaitu SurveyMonkey kepada lebih dari 100 orang pelajar. Melalui kajian ini terdapat enam perkara yang diperhatikan dan dikaji secara terperinci. Kajian ini berkisar komitmen pelajar dan pensyarah di kampus antaranya ialah komitmen pelajar terhadap pemakaian kad pelajar universiti (kad matrik), komitmen pensyarah memperuntukkan masa dalam kelas bagi menyatakan kepentingan tatacara berpakaian dan rupa diri di kampus, komitmen mengambil tindakan terhadap pelajar yang gagal mematuhi peraturan tatacara berpakaian dan rupa diri, komitmen mengambil tindakan terhadap pelajar yang lewat atau gagal hadir dalam kelas, dan amanah dalam mengisi ruang di slip kehadiran rakan sekuliah dalam kelas. Hasil kajian mendapati bahawa komitmen di kalangan pelajar dan pensyarah kurang memberangsangkan. Perkara ini harus dipandang serius dan sangat membimbangkan kerana penekanan terhadap isu-isu tersebut sangat penting dalam melahirkan pelajar bertamadun iaitu berpengetahuan luas, berkemahiran tinggi dan bersikap, berakhlak serta bersahsiah terpuji

Teaching introductory undergraduate Physics using commercial video games

Commercial video games are increasingly using sophisticated physics simulations to create a more immersive experience for players. This also makes them a powerful tool for engaging students in learning physics. We provide some examples to show how commercial off-the-shelf games can be used to teach specific topics in introductory undergraduate physics. The examples are selected from a course taught predominantly through the medium of commercial video games.Comment: Accepted to Physics Education, Fig1 does not render properly in this versio

Dual-pump CARS of Air in a Heated Pressure Vessel up to 55 Bar and 1300 K

Dual-pump Coherent anti-Stokes Raman scattering (CARS) measurements have been performed in a heated pressure vessel at NASA Langley Research Center. Each measurement, consisting of 500 single shot spectra, was recorded at a fixed location in dry air at various pressures and temperatures, in a range of 0.03-5510(exp 5) Pa and 300-1373 K, where the temperature was varied using an electric heater. The maximum output power of the electric heater limited the combinations of pressures and temperatures that could be obtained. Charts of CARS signal versus temperature (at constant pressure) and signal versus pressure (at constant temperature) are presented and fit with an empirical model to validate the range of capability of the dual-pump CARS technique; averaged spectra at different conditions of pressure and temperature are also shown

Extracellular Superoxide Dismutase Expression in Papillary Thyroid Cancer Mesenchymal Stem/Stromal Cells Modulates Cancer Cell Growth and Migration

Tumor stroma-secreted growth factors, cytokines, and reactive oxygen species (ROS) influence tumor development from early stages to the metastasis phase. Previous studies have demonstrated downregulation of ROS-producing extracellular superoxide dismutase (SOD3) in thyroid cancer cell lines although according to recent data, the expression of SOD3 at physiological levels stimulates normal and cancer cell proliferation. Therefore, to analyze the expression of SOD3 in tumor stroma, we characterized stromal cells from the thyroid. We report mutually exclusive desmoplasia and inflammation in papillary and follicular thyroid cancers and the presence of multipotent mesenchymal stem/stromal cells (MSCs) in non-carcinogenic thyroids and papillary thyroid cancer (PTC). The phenotypic and differentiation characteristics of Thyroid MSCs and PTC MSCs were comparable with bone marrow MSCs. A molecular level analysis showed increased FIBROBLAST ACTIVATING PROTEIN, COLLAGEN 1 TYPE A1, TENASCIN, and SOD3 expression in PTC MSCs compared to Thyroid MSCs, suggesting the presence of MSCs with a fibrotic fingerprint in papillary thyroid cancer tumors and the autocrine-paracrine conversion of SOD3 expression, which was enhanced by cancer cells. Stromal SOD3 had a stimulatory effect on cancer cell growth and an inhibitory effect on cancer cell migration, thus indicating that SOD3 might be a novel player in thyroid tumor stroma

Clinicopathological evaluation of chronic traumatic encephalopathy in players of American football

IMPORTANCE: Players of American football may be at increased risk of long-term neurological conditions, particularly chronic traumatic encephalopathy (CTE). OBJECTIVE: To determine the neuropathological and clinical features of deceased football players with CTE. DESIGN, SETTING, AND PARTICIPANTS: Case series of 202 football players whose brains were donated for research. Neuropathological evaluations and retrospective telephone clinical assessments (including head trauma history) with informants were performed blinded. Online questionnaires ascertained athletic and military history. EXPOSURES: Participation in American football at any level of play. MAIN OUTCOMES AND MEASURES: Neuropathological diagnoses of neurodegenerative diseases, including CTE, based on defined diagnostic criteria; CTE neuropathological severity (stages I to IV or dichotomized into mild [stages I and II] and severe [stages III and IV]); informant-reported athletic history and, for players who died in 2014 or later, clinical presentation, including behavior, mood, and cognitive symptoms and dementia. RESULTS: Among 202 deceased former football players (median age at death, 66 years [interquartile range, 47-76 years]), CTE was neuropathologically diagnosed in 177 players (87%; median age at death, 67 years [interquartile range, 52-77 years]; mean years of football participation, 15.1 [SD, 5.2]), including 0 of 2 pre–high school, 3 of 14 high school (21%), 48 of 53 college (91%), 9 of 14 semiprofessional (64%), 7 of 8 Canadian Football League (88%), and 110 of 111 National Football League (99%) players. Neuropathological severity of CTE was distributed across the highest level of play, with all 3 former high school players having mild pathology and the majority of former college (27 [56%]), semiprofessional (5 [56%]), and professional (101 [86%]) players having severe pathology. Among 27 participants with mild CTE pathology, 26 (96%) had behavioral or mood symptoms or both, 23 (85%) had cognitive symptoms, and 9 (33%) had signs of dementia. Among 84 participants with severe CTE pathology, 75 (89%) had behavioral or mood symptoms or both, 80 (95%) had cognitive symptoms, and 71 (85%) had signs of dementia. CONCLUSIONS AND RELEVANCE: In a convenience sample of deceased football players who donated their brains for research, a high proportion had neuropathological evidence of CTE, suggesting that CTE may be related to prior participation in football.This study received support from NINDS (grants U01 NS086659, R01 NS078337, R56 NS078337, U01 NS093334, and F32 NS096803), the National Institute on Aging (grants K23 AG046377, P30AG13846 and supplement 0572063345-5, R01 AG1649), the US Department of Defense (grant W81XWH-13-2-0064), the US Department of Veterans Affairs (I01 CX001038), the Veterans Affairs Biorepository (CSP 501), the Veterans Affairs Rehabilitation Research and Development Traumatic Brain Injury Center of Excellence (grant B6796-C), the Department of Defense Peer Reviewed Alzheimer’s Research Program (grant 13267017), the National Operating Committee on Standards for Athletic Equipment, the Alzheimer’s Association (grants NIRG-15-362697 and NIRG-305779), the Concussion Legacy Foundation, the Andlinger Family Foundation, the WWE, and the NFL