1,371 research outputs found
Note on the chemical potential of decoupled matter in the Universe
Textbooks on cosmology exhibit a thermodynamic inconsistency for free
streaming, decoupled matter. It is connected here to the chemical potential,
which deviates from its equilibrium value , where is
the usual parameter of the Fermi-Dirac or Bose-Einstein distribution function.Comment: 4 pages late
Observational Derivation of Einstein's``Law of the Constancy of the Velocity of Light in Vacuo"
On the basis of Galilean invariance and the Doppler formula, combined with an
observational condition, it is shown that the constancy of the velocity of
light {\it in vacuo} can be derived, together with time-dilatation and Lorentz
contraction. It is not necessary to take the constancy as a postulate.Comment: 5 pages AIP-tex. Conference "Quantum Theory: Reconsideration of
Foundations 3", Vaxjo Sweden, June 2005. To appear in AIP conference serie
Bath generated work extraction in two-level systems
The spin-boson model, often used in NMR and ESR physics, quantum optics and
spintronics, is considered in a solvable limit to model a spin one-half
particle interacting with a bosonic thermal bath. By applying external pulses
to a non-equilibrium initial state of the spin, work can be extracted from the
thermalized bath. It occurs on the timescale T_2 inherent to transversal
(`quantum') fluctuations. The work (partly) arises from heat given off by the
surrounding bath, while the spin entropy remains constant during a pulse. This
presents a violation of the Clausius inequality and the Thomson formulation of
the second law (cycles cost work) for the two-level system.Comment: 5 pages Latex, uses aip-proceedings style files. Proceedings `Quantum
Limits to the Second Law', San Diego, July 200
Association of Factor V Secretion with Protein Kinase B Signaling in Platelets from Horses with Atypical Equine Thrombasthenia.
BackgroundTwo congenital bleeding diatheses have been identified in Thoroughbred horses: Glanzmann thrombasthenia (GT) and a second, novel diathesis associated with abnormal platelet function in response to collagen and thrombin stimulation.Hypothesis/objectivesPlatelet dysfunction in horses with this second thrombasthenia results from a secretory defect.AnimalsTwo affected and 6 clinically normal horses.MethodsEx vivo study. Washed platelets were examined for (1) expression of the αIIb-β3 integrin; (2) fibrinogen binding capacity in response to ADP and thrombin; (3) secretion of dense and α-granules; (4) activation of the mammalian target of rapamycin (mTOR)-protein kinase B (AKT) signaling pathway; and (5) cellular distribution of phosphatidylinositol-4-phosphate-3-kinase, class 2B (PIK3C2B) and SH2 containing inositol-5'-phosphatase 1 (SHIP1).ResultsPlatelets from affected horses expressed normal amounts of αIIb-β3 integrin and bound fibrinogen normally in response to ADP, but bound 80% less fibrinogen in response to thrombin. α-granules only released 50% as much Factor V as control platelets, but dense granules released their contents normally. Protein kinase B (AKT) phosphorylation was reduced after thrombin activation, but mTOR Complex 2 (mTORC2) and phosphoinositide-dependent kinase 1 (PDK1) signaling were normal. SH2-containing inositol-5'-phosphatase 1 (SHIP1) did not localize to the cytoskeleton of affected platelets and was decreased overall consistent with reduced AKT phosphorylation.Conclusions and clinical significanceDefects in fibrinogen binding, granule secretion, and signal transduction are unique to this thrombasthenia, which we designate as atypical equine thrombasthenia
The HPST Framework: A Case Study on an Organizational Tool Used to Understand Historical Narrative in a Social Studies Classroom
This dissertation chronicled a multifaceted study utilizing the Historical, Philosophical, Societal and a Takeaway (HPST) Framework; an organizational tool used for document analysis. Utilizing a case study format, this research unpacked how a charter school teacher used HPST within her own ninth grade Advanced Placement World History class. As a starting point, I offered an account of my own autobiographical narrative, chronicling through my attempt at ethnographic writing and infused with scholarly literature as needed. Consequently, this personal narrative was coupled with my professional experiences within the Social Studies field. Upon this foundation, this study explored the use of the HPST Framework for analyzing narratives and its complexities beyond the textbook. The intent of HPST was to help students analyze the interaction of the author, the text, and the reader. The research was geared to see to what degree students might draw out historical, philosophic, and socio-cultural frames reflected as complicated conversations. In particular, I was interested in examining U.S. students’ portrayals of marginalized groups within a context of world history and how these roles changed after students used the HPST Framework to analyze narrative passages.
The study uncovered that HPST could add to literature by prioritizing historical narratives to convey information through stories which humanize the people involved in significant world events. For this teacher, HPST served as a platform for student discussion because it took the existing classroom discourse about philosophy, politics, society, or power and cognitively arranged it in two levels for students to engage with the text and the author. This was followed by an analytical layer to enhance comprehension and critical thinking. With that said, students could easily identify the H and S; however, challenges were found in their understanding of the P. Moreover, HPST allowed students to engage in discovery learning instead of prescribed analysis by the teacher. Additionally, discussions were offered as to how this teacher with limited time or a restricted curriculum could modify HPST and still use it. Lastly, discourses were given as to how this educator used narratives in the past and how her teaching changed because of the HPST
Teachers’ experiences and perceptions regarding mobile augmented reality games: a case study of a teacher training
The literature has been recognizing the potential of mobile technologies, augmented reality (AR) and
game-based approaches in Education and recommends its adoption. Considering the scarcity of this
type of educational resources in the Portuguese context, it is relevant to create opportunities for
teachers and researchers to collaborate in the development of high-quality open resources to be
integrated into games available for all. To this end, a 50-hour continuous training course for teachers
was conducted to promote collaborative development of mobile AR game-based resources for
Science, Technology, Engineering and Mathematics learning. In this contribution, data from a
questionnaire applied at the beginning of the training is analysed to support assessment of teachers’
previous experiences and initial perceptions regarding mobile learning, AR use in Education and
game-based learning. The questionnaire was anonymous and 14 out of 16 teachers gave informed
consent to participate in this study. This data was triangulated with information collected through
participant observation from two researchers who were also the trainers and the authors of this paper.
Results reveal that teachers with different profiles attained this training. Nevertheless, most teachers
revealed naĂŻve perspectives on mobile and game-based learning and were unaware of AR
technologies and their potential use in education. Teacher profiles varied from those who
acknowledge not knowing and not using either of the three approaches in their teaching practices, nor
in their personal learning experiences, to those who seem to have somewhat accurate ideas. This
work is relevant as this case study is an empirical account of teachers practices and perspectives on
mobile AR games.publishe
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