9,162 research outputs found
On Two Complementary Types of Total Time Derivative in Classical Field Theories and Maxwell's Equations
Close insight into mathematical and conceptual structure of classical field
theories shows serious inconsistencies in their common basis. In other words,
we claim in this work to have come across two severe mathematical blunders in
the very foundations of theoretical hydrodynamics. One of the defects concerns
the traditional treatment of time derivatives in Eulerian hydrodynamic
description. The other one resides in the conventional demonstration of the
so-called Convection Theorem. Both approaches are thought to be necessary for
cross-verification of the standard differential form of continuity equation.
Any revision of these fundamental results might have important implications for
all classical field theories. Rigorous reconsideration of time derivatives in
Eulerian description shows that it evokes Minkowski metric for any flow field
domain without any previous postulation. Mathematical approach is developed
within the framework of congruences for general 4-dimensional differentiable
manifold and the final result is formulated in form of a theorem. A modified
version of the Convection Theorem provides a necessary cross-verification for a
reconsidered differential form of continuity equation. Although the approach is
developed for one-component (scalar) flow field, it can be easily generalized
to any tensor field. Some possible implications for classical electrodynamics
are also explored.Comment: no figure
Gravitational Repulsion within a Black-Hole using the Stueckelberg Quantum Formalism
We wish to study an application of Stueckelberg's relativistic quantum theory
in the framework of general relativity. We study the form of the wave equation
of a massive body in the presence of a Schwarzschild gravitational field. We
treat the mathematical behavior of the wavefunction also around and beyond the
horizon (r=2M). Classically, within the horizon, the time component of the
metric becomes spacelike and distance from the origin singularity becomes
timelike, suggesting an inevitable propagation of all matter within the horizon
to a total collapse at r=0. However, the quantum description of the wave
function provides a different understanding of the behavior of matter within
the horizon. We find that a test particle can almost never be found at the
origin and is more probable to be found at the horizon. Matter outside the
horizon has a very small wave length and therefore interference effects can be
found only on a very small atomic scale. However, within the horizon, matter
becomes totally "tachionic" and is potentially "spread" over all space. Small
location uncertainties on the atomic scale become large around the horizon, and
different mass components of the wave function can therefore interfere on a
stellar scale. This interference phenomenon, where the probability of finding
matter decreases as a function of the distance from the horizon, appears as an
effective gravitational repulsion.Comment: 20 pages, 6 figure
Grown organic matter as a fuel raw material resource
An extensive search was made on biomass production from the standpoint of climatic zones, water, nutrients, costs and energy requirements for many species. No exotic species were uncovered that gave hope for a bonanza of biomass production under culture, location, and management markedly different from those of existing agricultural concepts. A simulation analysis of biomass production was carried out for six species using conventional production methods, including their production costs and energy requirements. These estimates were compared with data on food, fiber, and feed production. The alternative possibility of using residues from food, feed, or lumber was evaluated. It was concluded that great doubt must be cast on the feasibility of producing grown organic matter for fuel, in competition with food, feed, or fiber. The feasibility of collecting residues may be nearer, but the competition for the residues for return to the soil or cellulosic production is formidable
Over-the-Counter Medication Use, Perceived Safety, and Decision-Making Behaviors in Pregnant Women
The purpose of this study was to determine which over-the-counter (OTC) medications women are using during pregnancy, and to assess patients’ perceived safety of these medications. In addition, the decision-making process utilized by pregnant women when choosing OTC drug therapy was explored, including sources of information and recommendation. The subjects included pregnant women 18 years and older. Subjects were solicited as a convenience sample by providing surveys in two urban women’s clinic waiting rooms. Of the 61 respondents, 96.3% had used an OTC medication, herbal, or vitamin during their current pregnancy. The most common products included prenatal vitamins, acetaminophen, cough drops, antacids, calcium, vitamin D, and DHA. The majority of women surveyed regarded over-the-counter medications, vitamins, and herbals as “safe, but would talk to a healthcare professional before using.” The most utilized sources of drug information during pregnancy were a physician (68.9%), midwife (55.7%), and the Internet (44.3%). There were an equal number of respondents obtaining general OTC information from apharmacist as from their family and friends (26.2%). Almost all subjects had used an over-the-counter medication during their pregnancy and the majority considered OTCs safe after first consulting a healthcare professional. Although a high percentage of subjects have obtained their information and recommendations from healthcare professionals, a very small proportion of subjects had utilized a pharmacist as a resource. Being drug experts and easily accessible members of the healthcare team, pharmacists have a responsibility to aid the obstetric population in the appropriate and safe use of over-the-counter drugs, vitamins, and herbals during pregnancy
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
Healthcare provider perceptions of clinical prediction rules
Objectives: To examine internal medicine and emergency medicine healthcare provider perceptions of usefulness of specific clinical prediction rules. Setting: The study took place in two academic medical centres. A web-based survey was distributed and completed by participants between 1 January and 31 May 2013. Participants: Medical doctors, doctors of osteopathy or nurse practitioners employed in the internal medicine or emergency medicine departments at either institution. Primary and secondary outcome measures: The primary outcome was to identify the clinical prediction rules perceived as most useful by healthcare providers specialising in internal medicine and emergency medicine. Secondary outcomes included comparing usefulness scores of specific clinical prediction rules based on provider specialty, and evaluating associations between usefulness scores and perceived characteristics of these clinical prediction rules. Results: Of the 401 healthcare providers asked to participate, a total of 263 (66%), completed the survey. The CHADS2 score was chosen by most internal medicine providers (72%), and Pulmonary Embolism Rule-Out Criteria (PERC) score by most emergency medicine providers (45%), as one of the top three most useful from a list of 24 clinical prediction rules. Emergency medicine providers rated their top three significantly more positively, compared with internal medicine providers, as having a better fit into their workflow (p=0.004),helping more with decision-making (p= 0.037), better fitting into their thought process when diagnosing patients (p= 0.001) and overall, on a 10-point scale, more useful (p= 0.009). For all providers, the perceived qualities of useful at point of care, helps with decision making, saves time diagnosing, fits into thought process, and should be the standard of clinical care correlated highly (\u3e= 0.65) with overall 10-point usefulness scores. Conclusions: Healthcare providers describe clear preferences for certain clinical prediction rules, based on medical specialty
Higher Education Instructional Change in a U.S. Context: Investigating the Scholarship of Teaching and Learning (SoTL) Innovations at Niagara University
A metà Settembre 2013, due degli autori di questo articolo sono stati a Lecce (Italia) realizzando una presentazionein una conferenza sull’istruzione superiore. In quella sede, è stato possibile condividere con i partecipanti i dieci cambiamenti più potenti e significativi che hanno avuto luogo nel vasto panoramadell’accademia americana. L’elenco si componeva di sviluppi di tipo teorico; così come da diversi livelli di implementazione e pratica presso l’Università di Niagara, nell’angolo Nord Est degli Stati Uniti. Tra le iniziative messe in evidenza è stata prima e soprattutto menzionato il lavoro di Ernest Boyer sulla Scholarshipof Teaching and Learning (SoTL), ovvero la sua visione su strade alternative comunque accademiche, basate sulla didattica, per il successo della formazione universitaria. Il percorso tracciato dal movimento SoTL cambia la cultura universitaria, collocando l’insegnamento come priorità ; e la “scholarship” (ricerca didattica) emergente dagli studi sull’innovazione didattica come una disciplina di ricerca che può alinearse ad altre nell’ambito accademico. Le esperienze all’Università Niagara forniscono sia un caso di studio dell’implementazione dei suddetti concetti in una moderna istituzione americana; sia un’opportunità per la comparazione con i vari casi delle istituzioni italiane. Inoltre, il lavoro portato avanti dall’università di Niagara risulta competitivo con riguardo ad alcune delle più riconosciute università americane, potendo essere considerato all’avanguardia dell’emergente movimentoSoTL. Questo articolo fornisce un breve resoconto e definizione del modello di Boyer su SoTL, suggerendo come le istituzioni potrebbero adottare tale paradigma sia come strategia per lo sviluppo professionale accademico, sia come adeguata base per la valutazione del lavoro del docente universitario
Cohesion, team mental models, and collective efficacy: Towards an integrated framework of team dynamics in sport
A nomological network on team dynamics in sports consisting of a multi-framework perspective is introduced and tested. The aim was to explore the interrelationship among cohesion, team mental models (TMM), collective-efficacy (CE), and perceived performance potential (PPP). Three hundred and forty college-aged soccer players representing 17 different teams (8 female and 9 male) participated in the study. They responded to surveys on team cohesion, TMM, CE and PPP. Results are congruent with the theoretical conceptualization of a parsimonious view of team dynamics in sports. Specifically, cohesion was found to be an exogenous variable predicting both TMM and CE beliefs. TMM and CE were correlated and predicted PPP, which in turn accounted for 59% of the variance of objective performance scores as measured by teams’ season record. From a theoretical standpoint, findings resulted in a parsimonious view of team dynamics, which may represent an initial step towards clarifying the epistemological roots and nomological network of various team-level properties. From an applied standpoint, results suggest that team expertise starts with the establishment of team cohesion. Following the establishment of cohesiveness, teammates are able to advance team-related schemas and a collective sense of confidence. Limitations and key directions for future research are outlined
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