Traumatic Brain Injury History is Associated with Earlier Age of Onset of Alzheimer Disease

PubMed Central

LoBue, Christian; Wadsworth, Hannah; Wilmoth, Kristin; Clem, Matthew; Hart, John; Womack, Kyle B.; Didehbani, Nyaz; Lacritz, Laura H.; Rossetti, Heidi C.; Cullum, C. Munro

2016-01-01

Objective This study examined whether a history of traumatic brain injury (TBI) is associated with earlier onset of Alzheimer disease (AD), independent of apolipoprotein ε4 status (Apoe4) and gender. Method Participants with a clinical diagnosis of AD (n=7625) were obtained from the National Alzheimer’s Coordinating Center Uniform Data Set, and categorized based on self-reported lifetime TBI with loss of consciousness (LOC) (TBI+ vs TBI-) and presence of Apoe4. ANCOVAs, controlling for gender, race, and education were used to examine the association between history of TBI, presence of Apoe4, and an interaction of both risk factors on estimated age of AD onset. Results Estimated AD onset differed by TBI history and Apoe4 independently (p’s <.001). The TBI+ group had a mean age of onset 2.5 years earlier than the TBI- group. Likewise, Apoe4 carriers had a mean age of onset 2.3 years earlier than non-carriers. While the interaction was non-significant (p = .34), participants having both a history of TBI and Apoe4 had the earliest mean age of onset compared to those with a TBI history or Apoe4 alone (MDifference = 2.8 & 2.7 years, respectively). These results remained unchanged when stratified by gender. Conclusions History of self-reported TBI can be associated with an earlier onset of AD-related cognitive decline, regardless of Apoe4 status and gender. TBI may be related to an underlying neurodegenerative process in AD, but the implications of age at time of injury, severity, and repetitive injuries remain unclear. PMID:27855547

Changes toward earlier streamflow timing across western North America

USGS Publications Warehouse

Stewart, I.T.; Cayan, D.R.; Dettinger, M.D.

2005-01-01

The highly variable timing of streamflow in snowmelt-dominated basins across western North America is an important consequence, and indicator, of climate fluctuations. Changes in the timing of snowmelt-derived streamflow from 1948 to 2002 were investigated in a network of 302 western North America gauges by examining the center of mass for flow, spring pulse onset dates, and seasonal fractional flows through trend and principal component analyses. Statistical analysis of the streamflow timing measures with Pacific climate indicators identified local and key large-scale processes that govern the regionally coherent parts of the changes and their relative importance. Widespread and regionally coherent trends toward earlier onsets of springtime snowmelt and streamflow have taken place across most of western North America, affecting an area that is much larger than previously recognized. These timing changes have resulted in increasing fractions of annual flow occurring earlier in the water year by 1-4 weeks. The immediate (or proximal) forcings for the spatially coherent parts of the year-to-year fluctuations and longer-term trends of streamflow timing have been higher winter and spring temperatures. Although these temperature changes are partly controlled by the decadal-scale Pacific climate mode [Pacific decadal oscillation (PDO)], a separate and significant part of the variance is associated with a springtime warming trend that spans the PDO phases. ?? 2005 American Meteorological Society.

Advanced turboprop noise prediction based on recent theoretical results

NASA Technical Reports Server (NTRS)

Farassat, F.; Padula, S. L.; Dunn, M. H.

1987-01-01

The development of a high speed propeller noise prediction code at Langley Research Center is described. The code utilizes two recent acoustic formulations in the time domain for subsonic and supersonic sources. The structure and capabilities of the code are discussed. Grid size study for accuracy and speed of execution on a computer is also presented. The code is tested against an earlier Langley code. Considerable increase in accuracy and speed of execution are observed. Some examples of noise prediction of a high speed propeller for which acoustic test data are available are given. A brisk derivation of formulations used is given in an appendix.

Research promises earlier warning for grapevine canker diseases

USDA-ARS?s Scientific Manuscript database

When it comes to detecting and treating vineyards for grapevine canker diseases (also called trunk diseases), like Botryosphaeria dieback (Bot canker), Esca, Eutypa dieback and Phomopsis dieback, the earlier the better, says plant pathologist Kendra Baumgartner, with the USDA’s Agricultural Research...

An earlier de motu cordis.

PubMed Central

Daly, Walter J.

2004-01-01

Thirteenth century medical science, like medieval scholarship in general, was directed at reconciliation of Greek philosophy/science with prevailing medieval theology and philosophy. Peter of Spain [later Pope John XXI] was the leading medical scholar of his time. Peter wrote a long book on the soul. Imbedded in it was a chapter on the motion of the heart. Peter's De Motu was based on his own medical experience and Galen's De Usu Partium and De Usu Respirationis and De Usu Pulsuum. This earlier De Motu defines a point on the continuum of intellectual development leading to us and into the future. Thirteenth century scholarship relied on past authority to a degree that continues to puzzle and beg explanation. Images Fig. 1 PMID:17060956

Cardiac Complications, Earlier Treatment, and Initial Disease Severity in Kawasaki Disease.

PubMed

Abrams, Joseph Y; Belay, Ermias D; Uehara, Ritei; Maddox, Ryan A; Schonberger, Lawrence B; Nakamura, Yosikazu

2017-09-01

To assess if observed higher observed risks of cardiac complications for patients with Kawasaki disease (KD) treated earlier may reflect bias due to confounding from initial disease severity, as opposed to any negative effect of earlier treatment. We used data from Japanese nationwide KD surveys from 1997 to 2004. Receipt of additional intravenous immunoglobulin (IVIG) (data available all years) or any additional treatment (available for 2003-2004) were assessed as proxies for initial disease severity. We determined associations between earlier or later IVIG treatment (defined as receipt of IVIG on days 1-4 vs days 5-10 of illness) and cardiac complications by stratifying by receipt of additional treatment or by using logistic modeling to control for the effect of receiving additional treatment. A total of 48 310 patients with KD were included in the analysis. In unadjusted analysis, earlier IVIG treatment was associated with a higher risk for 4 categories of cardiac complications, including all major cardiac complications (risk ratio, 1.10; 95% CI, 1.06-1.15). Stratifying by receipt of additional treatment removed this association, and earlier IVIG treatment became protective against all major cardiac complications when controlling for any additional treatment in logistic regressions (OR, 0.90; 95% CI, 0.80-1.00). Observed higher risks of cardiac complications among patients with KD receiving IVIG treatment on days 1-4 of the illness are most likely due to underlying higher initial disease severity, and patients with KD should continue to be treated with IVIG as early as possible. Published by Elsevier Inc.

Travelling for earlier surgical treatment: the patient's view.

PubMed Central

Stewart, M; Donaldson, L J

1991-01-01

As part of the northern region's programme within the national waiting list initiative, schemes have been funded to test the feasibility and acceptability of offering patients the opportunity to travel further afield in order to receive earlier treatment. A total of 484 patients experiencing a long wait for routine surgical operations in the northern region were offered the opportunity to receive earlier treatment outside their local health district; 74% of the patients accepted the offer. The initiative was well received by the participating patients and the majority stated that if the need arose on a future occasion they would prefer to travel for treatment rather than have to wait for lengthy periods for treatment at their local hospital. These findings, interpreted in the light of the National Health Service reforms introduced in April 1991, suggest that for some types of care, patients would welcome greater flexibility in the placing of contracts, not merely reinforcement of historical patterns of referral. PMID:1823553

Theoretical molecular studies of astrophysical interest

NASA Technical Reports Server (NTRS)

Flynn, George

1991-01-01

When work under this grant began in 1974 there was a great need for state-to-state collisional excitation rates for interstellar molecules observed by radio astronomers. These were required to interpret observed line intensities in terms of local temperatures and densities, but, owing to lack of experimental or theoretical values, estimates then being used for this purpose ranged over several orders of magnitude. A problem of particular interest was collisional excitation of formaldehyde; Townes and Cheung had suggested that the relative size of different state-to-state rates (propensity rules) was responsible for the anomalous absorption observed for this species. We believed that numerical molecular scattering techniques (in particular the close coupling or coupled channel method) could be used to obtain accurate results, and that these would be computationally feasible since only a few molecular rotational levels are populated at the low temperatures thought to prevail in the observed regions. Such calculations also require detailed knowledge of the intermolecular forces, but we thought that those could also be obtained with sufficient accuracy by theoretical (quantum chemical) techniques. Others, notably Roy Gordon at Harvard, had made progress in solving the molecular scattering equations, generally using semi-empirical intermolecular potentials. Work done under this grant generalized Gordon's scattering code, and introduced the use of theoretical interaction potentials obtained by solving the molecular Schroedinger equation. Earlier work had considered only the excitation of a diatomic molecule by collisions with an atom, and we extended the formalism to include excitation of more general molecular rotors (e.g., H2CO, NH2, and H2O) and also collisions of two rotors (e.g., H2-H2).

Earlier surgical intervention in congenital heart disease results in better outcome and resource utilization.

PubMed

Panni, Roheena Z; Ashfaq, Awais; Amanullah, Muhammad M

2011-12-29

Congenital heart disease (CHD) accounts for a major proportion of disease in the pediatric age group. The objective of the study was to estimate the cost of illness associated with CHD pre, intra and postoperatively; among patients referred to a tertiary care hospital in Karachi, Pakistan. This is the first study conducted to estimate the cost of managing CHD in Pakistan. A prevalence based cost of illness study design was used to estimate the cost of cardiac surgery (corrective & palliative) for congenital heart defects in children ≤ 5 years of age from June 2006 to June 2009. A total of 120 patients were enrolled after obtaining an informed consent and the data was collected using a pre-tested questionnaire. The mean age at the time of surgery in group A (1-12 mo age) was 6.08 ± 2.80 months and in group B (1-5 yrs) was 37.10 ± 19.94 months. The cost of surgical admission was found to be significantly higher in the older group, p = 0.001. The total number and cost of post-operative outpatient visits was also higher in group B, p = 0.003. Pre and post operative hospital admissions were not found to be significantly different among the two groups, p = 0.166 and 0.627, respectively. The number of complications were found to be different between the two groups (p = 0.019). Majority of these were contributed by hemorrhage and post-operative seizures. This study concluded that significant expenditure is incurred by people with CHD; with the implication that resources could be saved by earlier detection and awareness campaigns.

Prescription stimulant use is associated with earlier onset of psychosis.

PubMed

Moran, Lauren V; Masters, Grace A; Pingali, Samira; Cohen, Bruce M; Liebson, Elizabeth; Rajarethinam, R P; Ongur, Dost

2015-12-01

A childhood history of attention deficit hyperactivity disorder (ADHD) is common in psychotic disorders, yet prescription stimulants may interact adversely with the physiology of these disorders. Specifically, exposure to stimulants leads to long-term increases in dopamine release. We therefore hypothesized that individuals with psychotic disorders previously exposed to prescription stimulants will have an earlier onset of psychosis. Age of onset of psychosis (AOP) was compared in individuals with and without prior exposure to prescription stimulants while controlling for potential confounding factors. In a sample of 205 patients recruited from an inpatient psychiatric unit, 40% (n = 82) reported use of stimulants prior to the onset of psychosis. Most participants were prescribed stimulants during childhood or adolescence for a diagnosis of ADHD. AOP was significantly earlier in those exposed to stimulants (20.5 vs. 24.6 years stimulants vs. no stimulants, p < 0.001). After controlling for gender, IQ, educational attainment, lifetime history of a cannabis use disorder or other drugs of abuse, and family history of a first-degree relative with psychosis, the association between stimulant exposure and earlier AOP remained significant. There was a significant gender × stimulant interaction with a greater reduction in AOP for females, whereas the smaller effect of stimulant use on AOP in males did not reach statistical significance. In conclusion, individuals with psychotic disorders exposed to prescription stimulants had an earlier onset of psychosis, and this relationship did not appear to be mediated by IQ or cannabis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discharging patients earlier in the day: a concept worth evaluating.

PubMed

Kravet, Steven J; Levine, Rachel B; Rubin, Haya R; Wright, Scott M

2007-01-01

Patient discharges from the hospital often occur late in the day and are frequently clustered after 4 PM. When inpatients leave earlier in the day, quality is improved because new admissions awaiting beds are able to leave the emergency department sooner and emergency department waiting room backlog is reduced. Nursing staff, whose work patterns traditionally result in high activity of discharge and admission between 5 PM and 8 PM, benefit by spreading out their work across a longer part of the day. Discharging patients earlier in the day also has the potential to increase patient satisfaction. Despite multiple stakeholders in the discharge planning process, physicians play the most important role. Getting physician buy-in requires an ability to teach physicians about the concept of early-in-the-day discharges and their impact on the process. We defined a new physician-centered discharge planning process and introduced it to an internal medicine team with an identical control team as a comparison. Discharge time of day was analyzed for 1 month. Mean time of day of discharge was 13:39 for the intervention group versus 15:45 for the control group (P<.001). If reproduced successfully, this process could improve quality at an important transition point in patient care.

Earlier warning: a multi-indicator approach to monitoring trends in the illicit use of medicines.

PubMed

Mounteney, Jane; Haugland, Siren

2009-03-01

The availability of medicines on the illicit drug market is currently high on the international policy agenda, linked to adverse health consequences including addiction, drug related overdoses and injection related problems. Continuous surveillance of illicit use of medicines allows for earlier identification and reporting of emerging trends and increased possibilities for earlier intervention to prevent spread of use and drug related harm. This paper aims to identify data sources capable of monitoring the illicit use of medicines; present trend findings for Rohypnol and Subutex using a multi-indicator monitoring approach; and consider the relevance of such models for policy makers. Data collection and analysis were undertaken in Bergen, Norway, using the Bergen Earlier Warning System (BEWS), a multi-indicator drug monitoring system. Data were gathered at six monthly intervals from April 2002 to September 2006. Drug indicator data from seizures, treatment, pharmacy sales, helplines, key informants and media monitoring were triangulated and an aggregated differential was used to plot trends. Results for the 4-year period showed a decline in the illicit use of Rohypnol and an increase in the illicit use of Subutex. Multi-indicator surveillance models can play a strategic role in the earlier identification and reporting of emerging trends in illicit use of medicines.

Swinging Atwood Machine: Experimental and numerical results, and a theoretical study

NASA Astrophysics Data System (ADS)

Pujol, O.; Pérez, J. P.; Ramis, J. P.; Simó, C.; Simon, S.; Weil, J. A.

2010-06-01

A Swinging Atwood Machine ( SAM) is built and some experimental results concerning its dynamic behaviour are presented. Experiments clearly show that pulleys play a role in the motion of the pendulum, since they can rotate and have non-negligible radii and masses. Equations of motion must therefore take into account the moment of inertia of the pulleys, as well as the winding of the rope around them. Their influence is compared to previous studies. A preliminary discussion of the role of dissipation is included. The theoretical behaviour of the system with pulleys is illustrated numerically, and the relevance of different parameters is highlighted. Finally, the integrability of the dynamic system is studied, the main result being that the machine with pulleys is non-integrable. The status of the results on integrability of the pulley-less machine is also recalled.

An experimental and theoretical study of reaction mechanisms between nitriles and hydroxylamine.

PubMed

Vörös, Attila; Mucsi, Zoltán; Baán, Zoltán; Timári, Géza; Hermecz, István; Mizsey, Péter; Finta, Zoltán

2014-10-28

The industrially relevant reaction between nitriles and hydroxylamine yielding amidoximes was studied in different molecular solvents and in ionic liquids. In industry, this procedure is carried out on the ton scale in alcohol solutions and the above transformation produces a significant amount of unexpected amide by-product, depending on the nature of the nitrile, which can cause further analytical and purification issues. Although there were earlier attempts to propose mechanisms for this transformation, the real reaction pathway is still under discussion. A new detailed reaction mechanistic explanation, based on theoretical and experimental proof, is given to augment the former mechanisms, which allowed us to find a more efficient, side-product free procedure. Interpreting the theoretical results obtained, it was shown that the application of specific imidazolium, phosphonium and quaternary ammonium based ionic liquids could decrease simultaneously the reaction time while eliminating the amide side-product, leading to the targeted product selectively. This robust and economic procedure now affords a fast, selective amide free synthesis of amidoximes.

Compulsive Buying: Earlier Illicit Drug Use, Impulse Buying, Depression, and Adult ADHD Symptoms

PubMed Central

Brook, Judith S.; Zhang, Chenshu; Brook, David W.; Leukefeld, Carl G.

2015-01-01

This longitudinal study examined the association between psychosocial antecedents, including illicit drug use, and adult compulsive buying (CB) across a 29-year time period from mean age 14 to mean age 43. Participants originally came from a community-based random sample of residents in two upstate New York counties. Multivariate linear regression analysis was used to study the relationship between the participant’s earlier psychosocial antecedents and adult CB in the fifth decade of life. The results of the multivariate linear regression analyses showed that gender (female), earlier adult impulse buying (IB), depressive mood, illicit drug use, and concurrent ADHD symptoms were all significantly associated with adult CB at mean age 43. It is important that clinicians treating CB in adults should consider the role of drug use, symptoms of ADHD, IB, depression, and family factors in CB. PMID:26165963

Surface electromagnetic waves in Fibonacci superlattices: Theoretical and experimental results

NASA Astrophysics Data System (ADS)

El Hassouani, Y.; Aynaou, H.; El Boudouti, E. H.; Djafari-Rouhani, B.; Akjouj, A.; Velasco, V. R.

2006-07-01

We study theoretically and experimentally the existence and behavior of the localized surface modes in one-dimensional (1D) quasiperiodic photonic band gap structures. These structures are made of segments and loops arranged according to a Fibonacci sequence. The experiments are carried out by using coaxial cables in the frequency region of a few tens of MHz. We consider 1D periodic structures (superlattice) where each cell is a well-defined Fibonacci generation. In these structures, we generalize a theoretical rule on the surface modes, namely when one considers two semi-infinite superlattices obtained by the cleavage of an infinite superlattice, it exists exactly one surface mode in each gap. This mode is localized on the surface either of one or the other semi-infinite superlattice. We discuss the existence of various types of surface modes and their spatial localization. The experimental observation of these modes is carried out by measuring the transmission through a guide along which a finite superlattice (i.e., constituted of a finite number of quasiperiodic cells) is grafted vertically. The surface modes appear as maxima of the transmission spectrum. These experiments are in good agreement with the theoretical model based on the formalism of the Green function.

Endochondral fracture healing with external fixation in the Sost knockout mouse results in earlier fibrocartilage callus removal and increased bone volume fraction and strength.

PubMed

Morse, A; Yu, N Y C; Peacock, L; Mikulec, K; Kramer, I; Kneissel, M; McDonald, M M; Little, D G

2015-02-01

Sclerostin deficiency, via genetic knockout or anti-Sclerostin antibody treatment, has been shown to cause increased bone volume, density and strength of calluses following endochondral bone healing. However, there is limited data on the effect of Sclerostin deficiency on the formative early stage of fibrocartilage (non-bony tissue) formation and removal. In this study we extensively investigate the early fibrocartilage callus. Closed tibial fractures were performed on Sost(-/-) mice and age-matched wild type (C57Bl/6J) controls and assessed at multiple early time points (7, 10 and 14days), as well as at 28days post-fracture after bony union. External fixation was utilized, avoiding internal pinning and minimizing differences in stability stiffness, a variable that has confounded previous research in this area. Normal endochondral ossification progressed in wild type and Sost(-/-) mice with equivalent volumes of fibrocartilage formed at early day 7 and day 10 time points, and bony union in both genotypes by day 28. There were no significant differences in rate of bony union; however there were significant increases in fibrocartilage removal from the Sost(-/-) fracture calluses at day 14 suggesting earlier progression of endochondral healing. Earlier bone formation was seen in Sost(-/-) calluses over wild type with greater bone volume at day 10 (221%, p<0.01). The resultant Sost(-/-) united bony calluses at day 28 had increased bone volume fraction compared to wild type calluses (24%, p<0.05), and the strength of the fractured Sost(-/-) tibiae was greater than that that of wild type fractured tibiae. In summary, bony union was not altered by Sclerostin deficiency in externally-fixed closed tibial fractures, but fibrocartilage removal was enhanced and the resultant united bony calluses had increased bone fraction and increased strength. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Compulsive buying: Earlier illicit drug use, impulse buying, depression, and adult ADHD symptoms.

PubMed

Brook, Judith S; Zhang, Chenshu; Brook, David W; Leukefeld, Carl G

2015-08-30

This longitudinal study examined the association between psychosocial antecedents, including illicit drug use, and adult compulsive buying (CB) across a 29-year time period from mean age 14 to mean age 43. Participants originally came from a community-based random sample of residents in two upstate New York counties. Multivariate linear regression analysis was used to study the relationship between the participant's earlier psychosocial antecedents and adult CB in the fifth decade of life. The results of the multivariate linear regression analyses showed that gender (female), earlier adult impulse buying (IB), depressive mood, illicit drug use, and concurrent ADHD symptoms were all significantly associated with adult CB at mean age 43. It is important that clinicians treating CB in adults should consider the role of drug use, symptoms of ADHD, IB, depression, and family factors in CB. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Childhood hair product use and earlier age at menarche in a racially diverse study population: a pilot study.

PubMed

James-Todd, Tamarra; Terry, Mary Beth; Rich-Edwards, Janet; Deierlein, Andrea; Senie, Ruby

2011-06-01

Previous studies suggest that hair products containing endocrine disrupting chemicals could alter puberty. We evaluated the association between childhood hair product use and age at menarche in a racially diverse study population. We recruited 300 African-American, African-Caribbean, Hispanic, and white women from the New York City metropolitan area who were between 18-77 years of age. Data were collected retrospectively on hair oil, lotion, leave-in conditioner, perm, and other types of hair products used before age 13. Recalled age at menarche ranged from 8 to 19 years. We used multivariable binomial regression to evaluate the association between hair product use and age at menarche (<12 vs. ≥12), adjusting for potential confounders. African-Americans were more likely to use hair products and reached menarche earlier than other racial/ethnic groups. Women reporting childhood hair oil use had a risk ratio of 1.4 (95% confidence interval [CI]: 1.1-1.9) for earlier menarche, adjusting for race/ethnicity and year of birth. Hair perm users had an increased risk for earlier menarche (adjusted risk ratio = 1.4, 95% CI: 1.1-1.8). Other types of hair products assessed in this study were not associated with earlier menarche. Childhood hair oil and perm use were associated with earlier menarche. If replicated, these results suggest that hair product use may be important to measure in evaluating earlier age at menarche. Copyright © 2011 Elsevier Inc. All rights reserved.

Ethylenediammonium dication: H-bonded complexes with terephthalate, chloroacetate, phosphite, selenite and sulfamate anions. Detailed vibrational spectroscopic and theoretical studies of ethylenediammonium terephthalate

NASA Astrophysics Data System (ADS)

Marchewka, M. K.; Drozd, M.

2012-12-01

Crystalline complexes between ethylenediammonium dication and terephthalate, chloroacetate, phosphite, selenite and sulfamate anions were obtained by slow evaporation from water solution method. Room temperature powder infrared and Raman measurements were carried out. For ethylenediammonium terephthalate theoretical calculations of structure were performed by two ways: ab-initio HF and semiempirical PM3. In this case the PM3 method gave more accurate structure (closer to X-ray results). The additional PM3 calculations of vibrational spectra were performed. On the basis theoretical approach and earlier vibrational studies of similar compounds the vibrational assignments for observed bands have been proposed. All compounds were checked for second harmonic generation (SHG).

Theoretical versus experimental results for the rotordynamic coefficients of eccentric, smooth, gas annular seal annular gas seals

NASA Technical Reports Server (NTRS)

Childs, Dara W.; Alexander, Chis

1994-01-01

This viewgraph presentation presents the following results: (1) The analytical results overpredict the experimental results for the direct stiffness values and incorrectly predict increasing stiffness with decreasing pressure ratios. (2) Theory correctly predicts increasing cross-coupled stiffness, K(sub YX), with increasing eccentricity and inlet preswirl. (3) Direct damping, C(sub XX), underpredicts the experimental results, but the analytical results do correctly show that damping increases with increasing eccentricity. (4) The whirl frequency values predicted by theory are insensitive to changes in the static eccentricity ratio. Although these values match perfectly with the experimental results at 16,000 rpm, the results at the lower speed do not correspond. (5) Theoretical and experimental mass flow rates match at 5000 rpm, but at 16,000 rpm the theoretical results overpredict the experimental mass flow rates. (6) Theory correctly shows the linear pressure profiles and the associated entrance losses with the specified rotor positions.

Return of hunger following a relatively high carbohydrate breakfast is associated with earlier recorded glucose peak and nadir

PubMed Central

Chandler-Laney, Paula C.; Morrison, Shannon A.; Goree, Laura Lee T.; Ellis, Amy C.; Casazza, Krista; Desmond, Renee; Gower, Barbara A

2014-01-01

Objective To test the hypothesis that a breakfast meal with high carbohydrate/ low fat results in an earlier increase in postprandial glucose and insulin, a greater decrease below baseline in postprandial glucose, and an earlier return of appetite, compared to a low carbohydrate/high fat meal. Design Overweight but otherwise healthy adults (n=64) were maintained on one of two eucaloric diets: high carbohydrate/low fat (HC/LF; 55:27:18% kcals from carbohydrate: fat: protein) versus low carbohydrate/high fat (LC/HF; 43:39:18% kcals from carbohydrate: fat: protein). After 4 weeks of acclimation to the diets, participants underwent a meal test during which circulating glucose and insulin and self-reported hunger and fullness, were measured before and after consumption of breakfast from their assigned diets. Results The LC/HF meal resulted in a later time at the highest and lowest recorded glucose, higher glucose concentrations at 3 and 4 hours post-meal, and lower insulin incremental area under the curve. Participants consuming the LC/HF meal reported lower appetite 3 and 4 hours following the meal, a response that was associated with the timing of the highest and lowest recorded glucose. Conclusions Modest increases in meal carbohydrate content at the expense of fat content may facilitate weight gain over the long-term by contributing to an earlier rise and fall of postprandial glucose concentrations and an earlier return of appetite. PMID:24819342

Comparison of Theoretical Stresses and Deflections of Multicell Wings with Experimental Results Obtained from Plastic Models

NASA Technical Reports Server (NTRS)

Zender, George W

1956-01-01

The experimental deflections and stresses of six plastic multicell-wing models of unswept, delta, and swept plan form are presented and compared with previously published theoretical results obtained by the electrical analog method. The comparisons indicate that the theory is reliable except for the evaluation of stresses in the vicinity of the leading edge of delta wings and the leading and trailing edges of swept wings. The stresses in these regions are questionable, apparently because of simplifications employed in idealizing the actual structure for theoretical purposes and because of local effects of concentrated loads.

An experimental and theoretical analysis of a foil-air bearing rotor system

NASA Astrophysics Data System (ADS)

Bonello, P.; Hassan, M. F. Bin

2018-01-01

Although there is considerable research on the experimental testing of foil-air bearing (FAB) rotor systems, only a small fraction has been correlated with simulations from a full nonlinear model that links the rotor, air film and foil domains, due to modelling complexity and computational burden. An approach for the simultaneous solution of the three domains as a coupled dynamical system, introduced by the first author and adopted by independent researchers, has recently demonstrated its capability to address this problem. This paper uses this approach, with further developments, in an experimental and theoretical study of a FAB-rotor test rig. The test rig is described in detail, including issues with its commissioning. The theoretical analysis uses a recently introduced modal-based bump foil model that accounts for interaction between the bumps and their inertia. The imposition of pressure constraints on the air film is found to delay the predicted onset of instability speed. The results lend experimental validation to a recent theoretically-based claim that the Gümbel condition may not be appropriate for a practical single-pad FAB. The satisfactory prediction of the salient features of the measured nonlinear behavior shows that the air film is indeed highly influential on the response, in contrast to an earlier finding.

Earlier Parental Set Bedtimes as a Protective Factor Against Depression and Suicidal Ideation

PubMed Central

Gangwisch, James E.; Babiss, Lindsay A.; Malaspina, Dolores; Turner, J. Blake; Zammit, Gary K.; Posner, Kelly

2010-01-01

Study Objectives: To examine the relationships between parental set bedtimes, sleep duration, and depression as a quasi-experiment to explore the potentially bidirectional relationship between short sleep duration and depression. Short sleep duration has been shown to precede depression, but this could be explained as a prodromal symptom of depression. Depression in an adolescent can affect his/her chosen bedtime, but it is less likely to affect a parent's chosen set bedtime which can establish a relatively stable upper limit that can directly affect sleep duration. Design: Multivariate cross-sectional analyses of the ADD Health using logistic regression. Setting: United States nationally representative, school-based, probability-based sample in 1994-96. Participants: Adolescents (n = 15,659) in grades 7 to 12. Measurements and Results: Adolescents with parental set bedtimes of midnight or later were 24% more likely to suffer from depression (OR = 1.24, 95% CI 1.04-1.49) and 20% more likely to have suicidal ideation (1.20, 1.01-1.41) than adolescents with parental set bedtimes of 10:00 PM or earlier, after controlling for covariates. Consistent with sleep duration and perception of getting enough sleep acting as mediators, the inclusion of these variables in the multivariate models appreciably attenuated the associations for depression (1.07, 0.88-1.30) and suicidal ideation (1.09, 0.92-1.29). Conclusions: The results from this study provide new evidence to strengthen the argument that short sleep duration could play a role in the etiology of depression. Earlier parental set bedtimes could therefore be protective against adolescent depression and suicidal ideation by lengthening sleep duration. Citation: Gangwisch JE; Babiss LA; Malaspina D; Turner JB; Zammit GK; Posner K. Earlier parental set bedtimes as a protective factor against depression and suicidal ideation. SLEEP 2010;33(1):97-106. PMID:20120626

When VSEPR Fails: Experimental and Theoretical Investigations of the Behavior of Alkaline-Earth-Metal Acetylides

PubMed Central

Guino-o, Marites A.; Alexander, Jacob S.; McKee, Michael L.; Hope, Håkon; Englich, Ulrich B.

2014-01-01

The synthesis, structural, and spectral characterization as well as a theoretical study of a family of alkaline-earth-metal acetylides provides insights into synthetic access and the structural and bonding characteristics of this group of highly reactive compounds. Based on our earlier communication that reported unusual geometry for a family of triphenylsilyl-substituted alkaline-earth-metal acetylides, we herein present our studies on an expanded family of target derivatives, providing experimental and theoretical data to offer new insights into the intensively debated theme of structural chemistry in heavy alkaline-earth-metal chemistry. PMID:19844925

Does Speech Emerge from Earlier Appearing Oral Motor Behaviors?.

ERIC Educational Resources Information Center

Moore, Christopher A.; Ruark, Jacki L.

1996-01-01

This study of the oral motor behaviors of seven toddlers (age 15 months) may be interpreted to indicate that: (1) mandibular coordination follows a developmental continuum from earlier emerging behaviors, such as chewing and sucking, through babbling, to speech, or (2) unique task demands give rise to distinct mandibular coordinative constraints…

The associations of earlier trauma exposures and history of mental disorders with PTSD after subsequent traumas

PubMed Central

Kessler, Ronald C.; Aguilar-Gaxiola, Sergio; Alonso, Jordi; Bromet, Evelyn J.; Gureje, Oye; Karam, Elie G.; Koenen, Karestan C.; Lee, Sing; Liu, Howard; Pennell, Beth-Ellen; Petukhova, Maria V.; Sampson, Nancy A.; Shahly, Victoria L.; Stein, Dan J.; Atwoli, Lukoye; Borges, Guilherme; Bunting, Brendan; de Girolamo, Giovanni; Gluzman, Semyon; Haro, Josep Maria; Hinkov, Hristo; Kawakami, Norito; Kovess-Masfety, Viviane; Navarro-Mateu, Fernando; Posada-Villa, Jose; Scott, Kate M.; Shalev, Arieh Y.; Have, Margreet ten; Torres, Yolanda; Viana, Maria Carmen; Zaslavsky, Alan M.

2017-01-01

Although earlier trauma exposure is known to predict post-traumatic stress disorder (PTSD) after subsequent traumas, it is unclear if this association is limited to cases where the earlier trauma led to PTSD. Resolution of this uncertainty has important implications for research on pre-trauma vulnerability to PTSD. We examined this issue in the WHO World Mental Health (WMH) Surveys with 34,676 respondents who reported lifetime trauma exposure. One lifetime trauma was selected randomly for each respondent. DSM-IV PTSD due to that trauma was assessed. We reported in a previous paper that four earlier traumas involving interpersonal violence significantly predicted PTSD after subsequent random traumas (OR=1.3–2.5). We also assessed 14 lifetime DSM-IV mood, anxiety, disruptive behavior, and substance disorders prior to random traumas. We show in the current report that only prior anxiety disorders significantly predicted PTSD in a multivariate model (OR=1.5–4.3) and that these disorders interacted significantly with three of the earlier traumas (witnessing atrocities, physical violence victimization, rape). History of witnessing atrocities significantly predicted PTSD after subsequent random traumas only among respondents with prior PTSD (OR=5.6). Histories of physical violence victimization (OR=1.5) and rape after age 17 (OR=17.6) significantly predicted only among respondents with no history of prior anxiety disorders. Although only preliminary due to reliance on retrospective reports, these results suggest that history of anxiety disorders and history of a limited number of earlier traumas might usefully be targeted in future prospective studies as distinct foci of research on individual differences in vulnerability to PTSD after subsequent traumas. PMID:28924183

Theoretical results on the tandem junction solar cell based on its Ebers-Moll transistor model

NASA Technical Reports Server (NTRS)

Goradia, C.; Vaughn, J.; Baraona, C. R.

1980-01-01

A one-dimensional theoretical model of the tandem junction solar cell (TJC) with base resistivity greater than about 1 ohm-cm and under low level injection has been derived. This model extends a previously published conceptual model which treats the TJC as an npn transistor. The model gives theoretical expressions for each of the Ebers-Moll type currents of the illuminated TJC and allows for the calculation of the spectral response, I(sc), V(oc), FF and eta under variation of one or more of the geometrical and material parameters and 1MeV electron fluence. Results of computer calculations based on this model are presented and discussed. These results indicate that for space applications, both a high beginning of life efficiency, greater than 15% AM0, and a high radiation tolerance can be achieved only with thin (less than 50 microns) TJC's with high base resistivity (greater than 10 ohm-cm).

Insight Into Illness and Cognition in Schizophrenia in Earlier and Later Life.

PubMed

Gerretsen, Philip; Voineskos, Aristotle N; Graff-Guerrero, Ariel; Menon, Mahesh; Pollock, Bruce G; Mamo, David C; Mulsant, Benoit H; Rajji, Tarek K

2017-04-01

Impaired insight into illness in schizophrenia is associated with illness severity and deficits in premorbid intellectual function, executive function, and memory. A previous study of patients aged 60 years and older found that illness severity and premorbid intellectual function accounted for variance in insight impairment. As such, we aimed to test whether similar relationships would be observed in earlier life. A retrospective analysis was performed on 1 large sample of participants (n = 171) with a DSM-IV-TR diagnosis of schizophrenia aged 19 to 79 years acquired from 2 studies: (1) a psychosocial intervention trial for older persons with schizophrenia (June 2008 to May 2014) and (2) a diffusion tensor imaging and genetics study of psychosis across the life span (February 2007 to December 2013). We assessed insight into illness using the Positive and Negative Syndrome Scale (PANSS) item G12 and explored its relationship to illness severity (PANSS total modified), premorbid intellectual function (Wechsler Test of Adult Reading [WTAR]), and cognition. Insight impairment was more severe in later life (≥ 60 years) than in earlier years (t = -3.75, P < .001). Across the whole sample, the variance of impaired insight was explained by PANSS total modified (Exp[B] = 1.070, P < .001) and WTAR scores (Exp[B] = 0.970, P = .028). Although age and cognition were correlated with impaired insight, they did not independently contribute to its variance. However, the relationships between impaired insight and illness severity and between impaired insight and cognition, particularly working memory, were stronger in later life than in earlier life. These results suggest an opportunity for intervention may exist with cognitive-enhancing neurostimulation or medications to improve insight into illness in schizophrenia across the life span. Original study registered on ClinicalTrials.gov (identifier: NCT00832845). © Copyright 2017 Physicians Postgraduate Press, Inc.

Reading-Related Skills in Earlier- and Later-Schooled Children

ERIC Educational Resources Information Center

Cunningham, Anna J.; Carroll, Julia M.

2011-01-01

We investigate the effects of age-related factors and formal instruction on the development of reading-related skills in children aged 4 and 7 years. Age effects were determined by comparing two groups of children at the onset of formal schooling; one aged 7 (later-schooled) and one aged 4 (earlier-schooled). Schooling effects were measured by…

The associations of earlier trauma exposures and history of mental disorders with PTSD after subsequent traumas.

PubMed

Kessler, R C; Aguilar-Gaxiola, S; Alonso, J; Bromet, E J; Gureje, O; Karam, E G; Koenen, K C; Lee, S; Liu, H; Pennell, B-E; Petukhova, M V; Sampson, N A; Shahly, V; Stein, D J; Atwoli, L; Borges, G; Bunting, B; de Girolamo, G; Gluzman, S F; Haro, J M; Hinkov, H; Kawakami, N; Kovess-Masfety, V; Navarro-Mateu, F; Posada-Villa, J; Scott, K M; Shalev, A Y; Ten Have, M; Torres, Y; Viana, M C; Zaslavsky, A M

2017-09-19

Although earlier trauma exposure is known to predict posttraumatic stress disorder (PTSD) after subsequent traumas, it is unclear whether this association is limited to cases where the earlier trauma led to PTSD. Resolution of this uncertainty has important implications for research on pretrauma vulnerability to PTSD. We examined this issue in the World Health Organization (WHO) World Mental Health (WMH) Surveys with 34 676 respondents who reported lifetime trauma exposure. One lifetime trauma was selected randomly for each respondent. DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition) PTSD due to that trauma was assessed. We reported in a previous paper that four earlier traumas involving interpersonal violence significantly predicted PTSD after subsequent random traumas (odds ratio (OR)=1.3-2.5). We also assessed 14 lifetime DSM-IV mood, anxiety, disruptive behavior and substance disorders before random traumas. We show in the current report that only prior anxiety disorders significantly predicted PTSD in a multivariate model (OR=1.5-4.3) and that these disorders interacted significantly with three of the earlier traumas (witnessing atrocities, physical violence victimization and rape). History of witnessing atrocities significantly predicted PTSD after subsequent random traumas only among respondents with prior PTSD (OR=5.6). Histories of physical violence victimization (OR=1.5) and rape after age 17 years (OR=17.6) significantly predicted only among respondents with no history of prior anxiety disorders. Although only preliminary due to reliance on retrospective reports, these results suggest that history of anxiety disorders and history of a limited number of earlier traumas might usefully be targeted in future prospective studies as distinct foci of research on individual differences in vulnerability to PTSD after subsequent traumas.Molecular Psychiatry advance online publication, 19 September 2017; doi:10.1038/mp.2017.194.

Ethylenediammonium dication: H-bonded complexes with terephthalate, chloroacetate, phosphite, selenite and sulfamate anions. Detailed vibrational spectroscopic and theoretical studies of ethylenediammonium terephthalate.

PubMed

Marchewka, M K; Drozd, M

2012-12-01

Crystalline complexes between ethylenediammonium dication and terephthalate, chloroacetate, phosphite, selenite and sulfamate anions were obtained by slow evaporation from water solution method. Room temperature powder infrared and Raman measurements were carried out. For ethylenediammonium terephthalate theoretical calculations of structure were performed by two ways: ab-initio HF and semiempirical PM3. In this case the PM3 method gave more accurate structure (closer to X-ray results). The additional PM3 calculations of vibrational spectra were performed. On the basis theoretical approach and earlier vibrational studies of similar compounds the vibrational assignments for observed bands have been proposed. All compounds were checked for second harmonic generation (SHG). Copyright © 2012 Elsevier B.V. All rights reserved.

Floodplains within reservoirs promote earlier spawning of white crappies Pomoxis annularis

USGS Publications Warehouse

Miranda, Leandro E.; Dagel, Jonah D.; Kaczka, Levi J.; Mower, Ethan; Wigen, S. L.

2015-01-01

Reservoirs impounded over floodplain rivers are unique because they may include within their upper reaches extensive shallow water stored over preexistent floodplains. Because of their relatively flat topography and riverine origin, floodplains in the upper reaches of reservoirs provide broad expanses of vegetation within a narrow range of reservoir water levels. Elsewhere in the reservoir, topography creates a band of shallow water along the contour of the reservoir where vegetation often does not grow. Thus, as water levels rise, floodplains may be the first vegetated habitats inundated within the reservoir. We hypothesized that shallow water in reservoir floodplains would attract spawning white crappies Pomoxis annularis earlier than reservoir embayments. Crappie relative abundance over five years in floodplains and embayments of four reservoirs increased as spawning season approached, peaked, and decreased as fish exited shallow water. Relative abundance peaked earlier in floodplains than embayments, and the difference was magnified with higher water levels. Early access to suitable spawning habitat promotes earlier spawning and may increase population fitness. Recognition of the importance of reservoir floodplains, an understanding of how reservoir water levels can be managed to provide timely connectivity to floodplains, and conservation of reservoir floodplains may be focal points of environmental management in reservoirs.

View northeast, wharf A, portion AA, details showing earlier piers ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View northeast, wharf A, portion AA, details showing earlier piers and braces sloping toward water, reused charred plates for existing decking - U.S. Coast Guard Sandy Hook Station, Western Docking Structure, West of intersection of Canfield Road & Hartshorne Drive, Highlands, Monmouth County, NJ

A vantage from space can detect earlier drought onset: an approach using relative humidity.

PubMed

Farahmand, Alireza; AghaKouchak, Amir; Teixeira, Joao

2015-02-25

Each year, droughts cause significant economic and agricultural losses across the world. The early warning and onset detection of drought is of particular importance for effective agriculture and water resource management. Previous studies show that the Standard Precipitation Index (SPI), a measure of precipitation deficit, detects drought onset earlier than other indicators. Here we show that satellite-based near surface air relative humidity data can further improve drought onset detection and early warning. This paper introduces the Standardized Relative Humidity Index (SRHI) based on the NASA Atmospheric Infrared Sounder (AIRS) observations. The results indicate that the SRHI typically detects the drought onset earlier than the SPI. While the AIRS mission was not originally designed for drought monitoring, we show that its relative humidity data offers a new and unique avenue for drought monitoring and early warning. We conclude that the early warning aspects of SRHI may have merit for integration into current drought monitoring systems.

A Vantage from Space Can Detect Earlier Drought Onset: An Approach Using Relative Humidity

PubMed Central

Farahmand, Alireza; AghaKouchak, Amir; Teixeira, Joao

2015-01-01

Each year, droughts cause significant economic and agricultural losses across the world. The early warning and onset detection of drought is of particular importance for effective agriculture and water resource management. Previous studies show that the Standard Precipitation Index (SPI), a measure of precipitation deficit, detects drought onset earlier than other indicators. Here we show that satellite-based near surface air relative humidity data can further improve drought onset detection and early warning. This paper introduces the Standardized Relative Humidity Index (SRHI) based on the NASA Atmospheric Infrared Sounder (AIRS) observations. The results indicate that the SRHI typically detects the drought onset earlier than the SPI. While the AIRS mission was not originally designed for drought monitoring, we show that its relative humidity data offers a new and unique avenue for drought monitoring and early warning. We conclude that the early warning aspects of SRHI may have merit for integration into current drought monitoring systems. PMID:25711500

Consideration of the Aluminum Distribution in Zeolites in Theoretical and Experimental Catalysis Research

DOE PAGES

Knott, Brandon C.; Nimlos, Claire T.; Robichaud, David J.; ...

2017-12-11

Research efforts in zeolite catalysis have become increasingly cognizant of the diversity in structure and function resulting from the distribution of framework aluminum atoms, through emerging reports of catalytic phenomena that fall outside those recognizable as the shape-selective ones emblematic of its earlier history. Molecular-level descriptions of how active-site distributions affect catalysis are an aspirational goal articulated frequently in experimental and theoretical research, yet they are limited by imprecise knowledge of the structure and behavior of the zeolite materials under interrogation. In experimental research, higher precision can result from more reliable control of structure during synthesis and from more robustmore » and quantitative structural and kinetic characterization probes. In theoretical research, construction of models with specific aluminum locations and distributions seldom capture the heterogeneity inherent to the materials studied by experiment. In this Perspective, we discuss research findings that appropriately frame the challenges in developing more predictive synthesis-structure-function relations for zeolites, highlighting studies on ZSM-5 zeolites that are among the most structurally complex molecular sieve frameworks and the most widely studied because of their versatility in commercial applications. We discuss research directions to address these challenges and forge stronger connections between zeolite structure, composition, and active sites to catalytic function. Such connections promise to aid in bridging the findings of theoretical and experimental catalysis research, and transforming zeolite active site design from an empirical endeavor into a more predictable science founded on validated models.« less

Consideration of the Aluminum Distribution in Zeolites in Theoretical and Experimental Catalysis Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knott, Brandon C.; Nimlos, Claire T.; Robichaud, David J.

Research efforts in zeolite catalysis have become increasingly cognizant of the diversity in structure and function resulting from the distribution of framework aluminum atoms, through emerging reports of catalytic phenomena that fall outside those recognizable as the shape-selective ones emblematic of its earlier history. Molecular-level descriptions of how active-site distributions affect catalysis are an aspirational goal articulated frequently in experimental and theoretical research, yet they are limited by imprecise knowledge of the structure and behavior of the zeolite materials under interrogation. In experimental research, higher precision can result from more reliable control of structure during synthesis and from more robustmore » and quantitative structural and kinetic characterization probes. In theoretical research, construction of models with specific aluminum locations and distributions seldom capture the heterogeneity inherent to the materials studied by experiment. In this Perspective, we discuss research findings that appropriately frame the challenges in developing more predictive synthesis-structure-function relations for zeolites, highlighting studies on ZSM-5 zeolites that are among the most structurally complex molecular sieve frameworks and the most widely studied because of their versatility in commercial applications. We discuss research directions to address these challenges and forge stronger connections between zeolite structure, composition, and active sites to catalytic function. Such connections promise to aid in bridging the findings of theoretical and experimental catalysis research, and transforming zeolite active site design from an empirical endeavor into a more predictable science founded on validated models.« less

Flight Measurements of Helicopter Blade Motion with a Comparison between Theoretical and Experimental Results

DTIC Science & Technology

1947-04-01

EXPERS5EHTAL RESULTS By G-arry C. Myers, Jr. STHMÄRY Hi order to provide " basic data on helicopter rotor-"blade motion, photographic .records of...ABOUT 2HE AXIS OF NO FEATHERING Reason for conversion.- At the time that the " basic theoretical treatments, such as that of reference 1, were made...of the machanical means used for achieving it. This fact may be confirmed by inspection but has also been demonstrated mathematically in reference

The association between cannabis use and earlier age at onset of schizophrenia and other psychoses: meta-analysis of possible confounding factors.

PubMed

Myles, Nicholas; Newall, Hannah; Nielssen, Olav; Large, Matthew

2012-01-01

A recent meta-analysis showed that the mean age of onset of psychosis among cannabis users was almost three years earlier than that of non-cannabis users. However, because cannabis users usually smoke tobacco, the use of tobacco might independently contribute to the earlier onset of psychosis. We aimed to use meta-analysis to compare the extent to which cannabis and tobacco use are each associated with an earlier age at onset of schizophrenia and other psychoses. We also examined other factors that might have contributed to the finding of an earlier age of onset among cannabis users, including the proportion of males in the samples, the diagnostic inclusion criteria and aspects of study quality. The electronic databases MEDLINE, EMBASE, PsycINFO and ISI Web of Science, were searched for English-language peer-reviewed publications that reported age at onset of schizophrenia and other psychoses separately for cannabis users and non-users, or for tobaccosmokers and non-smokers. Meta-analysis showed that the age at onset of psychosis for cannabis users was 32 months earlier than for cannabis non-users (SMD=- 0.399, 95%CI -0.493 - -0.306, z=-8.34, p < 0.001), and was two weeks later in tobacco smokers compared with non-smokers (SMD=0.002, 95%CI -0.094 - 0.097, z=0.03, p=0.974). The main results were not affected by subgroup analyses examining studies of a single sex, the methods for making psychiatric diagnoses and measures of study quality. The results suggest that the association between cannabis use and earlier onset of psychosis is robust and is not the result either of tobacco smoking by cannabis using patients or the other potentially confounding factors we examined. This supports the hypothesis that, in some patients, cannabis use plays a causal role in the development of schizophrenia and raises the possibility of treating schizophrenia with new pharmacological treatments that have an affinity for endo-cannabinoid receptors.

Standard model with a complex scalar singlet: Cosmological implications and theoretical considerations

NASA Astrophysics Data System (ADS)

Chiang, Cheng-Wei; Ramsey-Musolf, Michael J.; Senaha, Eibun

2018-01-01

We analyze the theoretical and phenomenological considerations for the electroweak phase transition and dark matter in an extension of the standard model with a complex scalar singlet (cxSM). In contrast with earlier studies, we use a renormalization group improved scalar potential and treat its thermal history in a gauge-invariant manner. We find that the parameter space consistent with a strong first-order electroweak phase transition (SFOEWPT) and present dark matter phenomenological constraints is significantly restricted compared to results of a conventional, gauge-noninvariant analysis. In the simplest variant of the cxSM, recent LUX data and a SFOEWPT require a dark matter mass close to half the mass of the standard model-like Higgs boson. We also comment on various caveats regarding the perturbative treatment of the phase transition dynamics.

Comprehensive methods for earlier detection and monitoring of forest decline

Treesearch

Jennifer Pontius; Richard Hallett

2014-01-01

Forested ecosystems are threatened by invasive pests, pathogens, and unusual climatic events brought about by climate change. Earlier detection of incipient forest health problems and a quantitatively rigorous assessment method is increasingly important. Here, we describe a method that is adaptable across tree species and stress agents and practical for use in the...

The min-conflicts heuristic: Experimental and theoretical results

NASA Technical Reports Server (NTRS)

Minton, Steven; Philips, Andrew B.; Johnston, Mark D.; Laird, Philip

1991-01-01

This paper describes a simple heuristic method for solving large-scale constraint satisfaction and scheduling problems. Given an initial assignment for the variables in a problem, the method operates by searching through the space of possible repairs. The search is guided by an ordering heuristic, the min-conflicts heuristic, that attempts to minimize the number of constraint violations after each step. We demonstrate empirically that the method performs orders of magnitude better than traditional backtracking techniques on certain standard problems. For example, the one million queens problem can be solved rapidly using our approach. We also describe practical scheduling applications where the method has been successfully applied. A theoretical analysis is presented to explain why the method works so well on certain types of problems and to predict when it is likely to be most effective.

Long-term effects of earlier initiated continuous Kangaroo Mother Care (KMC) for low-birth-weight (LBW) infants in Madagascar.

PubMed

Nagai, Shuko; Yonemoto, Naohiro; Rabesandratana, Norotiana; Andrianarimanana, Diavolana; Nakayama, Takeo; Mori, Rintaro

2011-12-01

To examine the long-term effects of earlier initiated continuous Kangaroo Mother Care (KMC) for relatively stable low-birth-weight (LBW) infants in a resource-limited country. A randomized controlled trial with long-term follow-up was performed in LBW infants in Madagascar. Earlier continuous KMC (intervention group) was initiated as soon as possible within 24 h postbirth, and later continuous KMC (control group: conventional care) was initiated after complete stabilization. Outcome measures were mortality or readmission, nutritional indicators at 6-12 months postbirth and feeding condition at 6 months postbirth (ClinicalTrials.gov, NCT00531492). A total of 72 infants were followed for mortality or readmission at 6-12 months postbirth. There was no difference between the two groups (7/36 vs. 7/36, Risk ratio (RR), 1.00; 95% CIs, 0.39-2.56; p = 1.00). The proportion of exclusive breast feeding (EBF) at 6 months postbirth was significantly higher with earlier KMC than later KMC (12/29 vs. 4/26; RR 2.69; 95% CIs, 1.00-7.31; p = 0.04). There were no differences in nutritional indicators between the two groups at 6-12 months postbirth. Earlier initiated continuous KMC results in a significantly higher proportion of EBF at 6 months postbirth. Further larger-scale long-term evaluations of earlier initiated continuous KMC for LBW infants are needed. © 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.

New theoretical results in synchrotron radiation

NASA Astrophysics Data System (ADS)

Bagrov, V. G.; Gitman, D. M.; Tlyachev, V. B.; Jarovoi, A. T.

2005-11-01

One of the remarkable features of the relativistic electron synchrotron radiation is its concentration in small angle Δ ≈ 1/γ (here γ-relativistic factor: γ = E/mc2, E energy, m electron rest mass, c light velocity) near rotation orbit plane [V.G. Bagrov, V.A. Bordovitsyn, V.G. Bulenok, V. Ya. Epp, Kinematical projection of pulsar synchrotron radiation profiles, in: Proceedings of IV ISTC Scientific Advisory Commitee Seminar on Basic Science in ISTC Aktivities, Akademgorodok, Novosibirsk, April 23 27, 2001, p. 293 300]. This theoretically predicted and experimentally confirmed feature is peculiar to total (spectrum summarized) radiating intensity. This angular distribution property has been supposed to be (at least qualitatively) conserved and for separate spectrum synchrotron radiation components. In the work of V.G. Bagrov, V.A. Bordovitsyn, V. Ch. Zhukovskii, Development of the theory of synchrotron radiation and related processes. Synchrotron source of JINR: the perspective of research, in: The Materials of the Second International Work Conference, Dubna, April 2 6, 2001, pp. 15 30 and in Angular dependence of synchrotron radiation intensity. http://lanl.arXiv.org/abs/physics/0209097, it is shown that the angular distribution of separate synchrotron radiation spectrum components demonstrates directly inverse tendency the angular distribution deconcentration relatively the orbit plane takes place with electron energy growth. The present work is devoted to detailed investigation of this situation. For exact quantitative estimation of angular concentration degree of synchrotron radiation the definition of radiation effective angle and deviation angle is proposed. For different polarization components of radiation the dependence of introduced characteristics was investigated as a functions of electron energy and number of spectrum component.

Reducing Older Driver Motor Vehicle Collisions via Earlier Cataract Surgery

PubMed Central

Mennemeyer, Stephen T.; Owsley, Cynthia; McGwin, Gerald

2013-01-01

Older adults who undergo cataract extraction have roughly half the rate of motor vehicle collision (MVC) involvement per mile driven compared to cataract patients who do not elect cataract surgery. Currently in the U.S., most insurers do not allow payment for cataract surgery based upon the findings of a vision exam unless accompanied by an individual’s complaint of visual difficulties that seriously interfere with driving or other daily activities and individuals themselves may be slow or reluctant to complain and seek relief. As a consequence, surgery tends to occur after significant vision problems have emerged. We hypothesize that a proactive policy encouraging cataract surgery earlier for a lesser level of complaint would significantly reduce MVCs among older drivers. We used a Monte Carlo model to simulate the MVC experience of the U.S. population from age 60 to 89 under alternative protocols for the timing of cataract surgery which we call “Current Practice” (CP) and “Earlier Surgery” (ES). Our base model finds, from a societal perspective with undiscounted 2010 dollars, that switching to ES from CP reduces by about 21% the average number of MVCs, fatalities, and MVC cost per person. The net effect on total cost – all MVC costs plus cataract surgery expenditures -- is a reduction of about 16%. Quality Adjusted Life Years would increase by about 5%. From the perspective of payers for healthcare, the switch would increase cataract surgery expenditure for ages 65+ by about 8% and for ages 60 to 64 by about 47% but these expenditures are substantially offset after age 65 by reductions in the medical and emergency services component of MVC cost. Similar results occur with discounting at 3% and with various sensitivity analyses. We conclude that a policy of ES would significantly reduce MVCs and their associated consequences. PMID:23369786

Daily Use, Especially of High-Potency Cannabis, Drives the Earlier Onset of Psychosis in Cannabis Users

PubMed Central

Di Forti, Marta; Sallis, Hannah; Allegri, Fabio; Trotta, Antonella; Ferraro, Laura; Stilo, Simona A.; Marconi, Arianna; La Cascia, Caterina; Reis Marques, Tiago; Pariante, Carmine; Dazzan, Paola; Mondelli, Valeria; Paparelli, Alessandra; Kolliakou, Anna; Prata, Diana; Gaughran, Fiona; David, Anthony S.; Morgan, Craig; Stahl, Daniel; Khondoker, Mizanur; MacCabe, James H.; Murray, Robin M.

2014-01-01

Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated. Methods: We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP. Results: Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16–1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11–1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06–1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users. Conclusions: Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users. PMID:24345517

Earlier Violent Television Exposure and Later Drug Dependence

PubMed Central

Brook, David W.; Katten, Naomi S.; Ning, Yuming; Brook, Judith S.

2013-01-01

This research examined the longitudinal pathways from earlier violent television exposure to later drug dependence. African American and Puerto Rican adolescents were interviewed during three points in time (N = 463). Violent television exposure in late adolescence predicted violent television exposure in young adulthood, which in turn was related to tobacco/marijuana use, nicotine dependence, and later drug dependence. Some policy and clinical implications suggest: a) regulating the times when violent television is broadcast; b) creating developmentally targeted prevention/treatment programs; and c) recognizing that watching violent television may serve as a cue regarding increased susceptibility to nicotine and drug dependence. PMID:18612881

Understanding Violence in Contemporary and Earlier Gangs: An Exploratory Application of the Theory of Reasoned Action.

ERIC Educational Resources Information Center

Evans, Judy P.; Taylor, Jerome

1995-01-01

Reviews the theory of reasoned action to demonstrate how it can be applied to understanding gang violence, and illustrates its potential applicability to a pilot sample of 30 contemporary and 18 earlier gangs living in a large metropolitan community. Results indicate this theory has been helpful in explaining higher levels of violence in…

The joint Simon effect: a review and theoretical integration

PubMed Central

Dolk, Thomas; Hommel, Bernhard; Colzato, Lorenza S.; Schütz-Bosbach, Simone; Prinz, Wolfgang; Liepelt, Roman

2014-01-01

The social or joint Simon effect has been developed to investigate how and to what extent people mentally represent their own and other persons' action/task and how these cognitive representations influence an individual's own behavior when interacting with another person. Here, we provide a review of the available evidence and theoretical frameworks. Based on this review, we suggest a comprehensive theory that integrates aspects of earlier approaches–the Referential Coding Account. This account provides an alternative to the social interpretation of the (joint) go-nogo Simon effect (aka the social Simon effect) and is able to integrate seemingly opposite findings on joint action. PMID:25249991

Theoretical performance of cross-wind axis turbines with results for a catenary vertical axis configuration

NASA Technical Reports Server (NTRS)

Muraca, R. J.; Stephens, M. V.; Dagenhart, J. R.

1975-01-01

A general analysis capable of predicting performance characteristics of cross-wind axis turbines was developed, including the effects of airfoil geometry, support struts, blade aspect ratio, windmill solidity, blade interference and curved flow. The results were compared with available wind tunnel results for a catenary blade shape. A theoretical performance curve for an aerodynamically efficient straight blade configuration was also presented. In addition, a linearized analytical solution applicable for straight configurations was developed. A listing of the computer program developed for numerical solutions of the general performance equations is included in the appendix.

Estimation of the Maximum Theoretical Productivity of Fed-Batch Bioreactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bomble, Yannick J; St. John, Peter C; Crowley, Michael F

2017-10-18

A key step towards the development of an integrated biorefinery is the screening of economically viable processes, which depends sharply on the yields and productivities that can be achieved by an engineered microorganism. In this study, we extend an earlier method which used dynamic optimization to find the maximum theoretical productivity of batch cultures to explicitly include fed-batch bioreactors. In addition to optimizing the intracellular distribution of metabolites between cell growth and product formation, we calculate the optimal control trajectory of feed rate versus time. We further analyze how sensitive the productivity is to substrate uptake and growth parameters.

Earlier Vegetation Activity Onset Enhances Springtime Water-use Efficiency in Temperate and Boreal Ecosystems

NASA Astrophysics Data System (ADS)

Jin, J.; Wang, Y.

2017-12-01

Ecosystem-scale water-use efficiency (EWUE), defined as the ratio of gross primary productivity (GPP) to evapotranspiration (ET), is an important indicator for understanding how water couples with the carbon cycle under global change. Relationships between EWUE and abiotic environmental factors (e.g. climatic factors, atmospheric CO2concentration and nitrogen deposition) have been widely investigated, but the variations in EWUE in response to biotic controls remain little understood. Here, we argue that phenology plays an important role in the regulation of EWUE by analyzing springtime EWUE responses to variability of the GPP-based vegetation activity onset (VAO) in temperate and boreal ecosystems using both satellite and flux-tower observations. Based on MODIS productions during 2000-2014, we found that spring EWUE widely significantly increased with the earlier VAO mainly in the mid- and high latitudes (over 50°N), southwestern China and mid-western North America. When AVO advanced a 10-day, the spring EWUE would increase on average by 0.17±0.09 g C kg-1 H2O in temperate and continental climates after removing the effect of environmental factors. The main response patterns of EWUE to phenology suggest that an increase in spring EWUE with an earlier VAO are mainly because the increase in GPP is relatively larger in magnitude compared to that of ET, or due to an increase in GPP accompanied by a decrease in ET, resulting from an advanced VAO. The credibility of the results is also supported by the local-scale observations. By analyzing 66 site-years of flux and meteorological data obtained from 8 temperate deciduous broadleaf forest sites across North America and Europe, spring EWUE increased 0.42±0.08 g C kg-1 H2O with a 10-day advance of VAO across all sites after controlling for environmental factors, mainly because an earlier VAO could lead to a steeper increase in GPP than in ET. Our results and conclusions highlight that phenological factors cannot be

Identifying pneumonia outbreaks of public health importance: can emergency department data assist in earlier identification?

PubMed

Hope, Kirsty; Durrheim, David N; Muscatello, David; Merritt, Tony; Zheng, Wei; Massey, Peter; Cashman, Patrick; Eastwood, Keith

2008-08-01

To retrospectively review the performance of a near real-time Emergency Department (ED) Syndromic Surveillance System operating in New South Wales for identifying pneumonia outbreaks of public health importance. Retrospective data was obtained from the NSW Emergency Department data collection for a rural hospital that has experienced a cluster of pneumonia diagnoses among teenage males in August 2006. ED standard reports were examined for signals in the overall count for each respiratory syndrome, and for elevated counts in individual subgroups including; age, sex and admission to hospital status. Using the current thresholds, the ED syndromic surveillance system would have trigged a signal for pneumonia syndrome in children aged 5-16 years four days earlier than the notification by a paediatrician and this signal was maintained for 14 days. If the ED syndromic surveillance system had been operating it could have identified the outbreak earlier than the paediatrician's notification. This may have permitted an earlier public health response. By understanding the behaviour of syndromes during outbreaks of public health importance, response protocols could be developed to facilitate earlier implementation of control measures.

Earlier vegetation green-up has reduced spring dust storms

PubMed Central

Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

2014-01-01

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p < 0.01) between green-up date and dust storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = −0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world. PMID:25343265

Earlier vegetation green-up has reduced spring dust storms.

PubMed

Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

2014-10-24

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p < 0.01) between green-up date and dust storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = -0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world.

To achieve an earlier IFN-γ response is not sufficient to control Mycobacterium tuberculosis infection in mice.

PubMed

Vilaplana, Cristina; Prats, Clara; Marzo, Elena; Barril, Carles; Vegué, Marina; Diaz, Jorge; Valls, Joaquim; López, Daniel; Cardona, Pere-Joan

2014-01-01

The temporo-spatial relationship between the three organs (lung, spleen and lymph node) involved during the initial stages of Mycobacterium tuberculosis infection has been poorly studied. As such, we performed an experimental study to evaluate the bacillary load in each organ after aerosol or intravenous infection and developed a mathematical approach using the data obtained in order to extract conclusions. The results showed that higher bacillary doses result in an earlier IFN-γ response, that a certain bacillary load (BL) needs to be reached to trigger the IFN-γ response, and that control of the BL is not immediate after onset of the IFN-γ response, which might be a consequence of the spatial dimension. This study may have an important impact when it comes to designing new vaccine candidates as it suggests that triggering an earlier IFN-γ response might not guarantee good infection control, and therefore that additional properties should be considered for these candidates.

To Achieve an Earlier IFN-γ Response Is Not Sufficient to Control Mycobacterium tuberculosis Infection in Mice

PubMed Central

Marzo, Elena; Barril, Carles; Vegué, Marina; Diaz, Jorge; Valls, Joaquim; López, Daniel; Cardona, Pere-Joan

2014-01-01

The temporo-spatial relationship between the three organs (lung, spleen and lymph node) involved during the initial stages of Mycobacterium tuberculosis infection has been poorly studied. As such, we performed an experimental study to evaluate the bacillary load in each organ after aerosol or intravenous infection and developed a mathematical approach using the data obtained in order to extract conclusions. The results showed that higher bacillary doses result in an earlier IFN-γ response, that a certain bacillary load (BL) needs to be reached to trigger the IFN-γ response, and that control of the BL is not immediate after onset of the IFN-γ response, which might be a consequence of the spatial dimension. This study may have an important impact when it comes to designing new vaccine candidates as it suggests that triggering an earlier IFN-γ response might not guarantee good infection control, and therefore that additional properties should be considered for these candidates. PMID:24959669

Earlier tachycardia onset in right than left mesial temporal lobe seizures.

PubMed

Kato, Kazuhiro; Jin, Kazutaka; Itabashi, Hisashi; Iwasaki, Masaki; Kakisaka, Yosuke; Aoki, Masashi; Nakasato, Nobukazu

2014-10-07

To clarify whether the presence and timing of peri-ictal heart rate (HR) change is a seizure lateralizing sign in patients with mesial temporal lobe epilepsy (mTLE). Long-term video EEGs were retrospectively reviewed in 21 patients, 7 men and 14 women aged 13 to 67 years, diagnosed as mTLE with MRI lesions in the mesial temporal structures (hippocampal sclerosis in 20 cases, amygdala hypertrophy in 1 case). Seventy-seven partial seizures without secondary generalization were extracted. Peri-ictal HR change was compared between 29 right seizures (9 patients) and 48 left seizures (12 patients). HR abruptly increased in all 29 right seizures and 42 of 48 left seizures. Onset time of HR increase in relation to ictal EEG onset was significantly earlier in right seizures than in left seizures (mean ± SD, -11.5 ± 14.8 vs 9.2 ± 21.7 seconds; p < 0.0001). Time of maximum HR was also significantly earlier in right seizures than in left seizures (36.0 ± 18.1 vs 58.0 ± 28.7 seconds; p < 0.0001). Maximum HR changes from baseline showed no significant difference between right and left seizures (47.5 ± 19.1 vs 40.8 ± 20.0/min). Significantly earlier tachycardia in right than left mTLE seizures supports previous hypotheses that the right cerebral hemisphere is dominant in the sympathetic network. No HR change, or delayed tachycardia possibly due to seizure propagation to the right hemisphere, may be a useful lateralizing sign of left mTLE seizures. © 2014 American Academy of Neurology.

Spatial and Temporal Variation in Primary Productivity (NDVI) of Coastal Alaskan Tundra: Decreased Vegetation Growth Following Earlier Snowmelt

NASA Technical Reports Server (NTRS)

Gamon, John A.; Huemmrich, K. Fred; Stone, Robert S.; Tweedie, Craig E.

2015-01-01

In the Arctic, earlier snowmelt and longer growing seasons due to warming have been hypothesized to increase vegetation productivity. Using the Normalized Difference Vegetation Index (NDVI) from both field and satellite measurements as an indicator of vegetation phenology and productivity, we monitored spatial and temporal patterns of vegetation growth for a coastal wet sedge tundra site near Barrow, Alaska over three growing seasons (2000-2002). Contrary to expectation, earlier snowmelt did not lead to increased productivity. Instead, productivity was associated primarily with precipitation and soil moisture, and secondarily with growing degree days, which, during this period, led to reduced growth in years with earlier snowmelt. Additional moisture effects on productivity and species distribution, operating over a longer time scale, were evident in spatial NDVI patterns associated with microtopography. Lower, wetter regions dominated by graminoids were more productive than higher, drier locations having a higher percentage of lichens and mosses, despite the earlier snowmelt at the more elevated sites. These results call into question the oft-stated hypothesis that earlier arctic growing seasons will lead to greater vegetation productivity. Rather, they agree with an emerging body of evidence from recent field studies indicating that early-season, local environmental conditions, notably moisture and temperature, are primary factors determining arctic vegetation productivity. For this coastal arctic site, early growing season conditions are strongly influenced by microtopography, hydrology, and regional sea ice dynamics, and may not be easily predicted from snowmelt date or seasonal average air temperatures alone. Our comparison of field to satellite NDVI also highlights the value of in-situ monitoring of actual vegetation responses using field optical sampling to obtain detailed information on surface conditions not possible from satellite observations alone.

Overview of RICOR's reliability theoretical analysis, accelerated life demonstration test results and verification by field data

NASA Astrophysics Data System (ADS)

Vainshtein, Igor; Baruch, Shlomi; Regev, Itai; Segal, Victor; Filis, Avishai; Riabzev, Sergey

2018-05-01

The growing demand for EO applications that work around the clock 24hr/7days a week, such as in border surveillance systems, emphasizes the need for a highly reliable cryocooler having increased operational availability and optimized system's Integrated Logistic Support (ILS). In order to meet this need, RICOR developed linear and rotary cryocoolers which achieved successfully this goal. Cryocoolers MTTF was analyzed by theoretical reliability evaluation methods, demonstrated by normal and accelerated life tests at Cryocooler level and finally verified by field data analysis derived from Cryocoolers operating at system level. The following paper reviews theoretical reliability analysis methods together with analyzing reliability test results derived from standard and accelerated life demonstration tests performed at Ricor's advanced reliability laboratory. As a summary for the work process, reliability verification data will be presented as a feedback from fielded systems.

Cooling of solar flares plasmas. 1: Theoretical considerations

NASA Technical Reports Server (NTRS)

Cargill, Peter J.; Mariska, John T.; Antiochos, Spiro K.

1995-01-01

Theoretical models of the cooling of flare plasma are reexamined. By assuming that the cooling occurs in two separate phase where conduction and radiation, respectively, dominate, a simple analytic formula for the cooling time of a flare plasma is derived. Unlike earlier order-of-magnitude scalings, this result accounts for the effect of the evolution of the loop plasma parameters on the cooling time. When the conductive cooling leads to an 'evaporation' of chromospheric material, the cooling time scales L(exp 5/6)/p(exp 1/6), where the coronal phase (defined as the time maximum temperature). When the conductive cooling is static, the cooling time scales as L(exp 3/4)n(exp 1/4). In deriving these results, use was made of an important scaling law (T proportional to n(exp 2)) during the radiative cooling phase that was forst noted in one-dimensional hydrodynamic numerical simulations (Serio et al. 1991; Jakimiec et al. 1992). Our own simulations show that this result is restricted to approximately the radiative loss function of Rosner, Tucker, & Vaiana (1978). for different radiative loss functions, other scaling result, with T and n scaling almost linearly when the radiative loss falls off as T(exp -2). It is shown that these scaling laws are part of a class of analytic solutions developed by Antiocos (1980).

A theoretical model of job retention for home health care nurses.

PubMed

Ellenbecker, Carol Hall

2004-08-01

Predicted severe nursing shortages and an increasing demand for home health care services have made the retention of experienced, qualified nursing staff a priority for health care organizations. The purpose of this paper is to describe a theoretical model of job retention for home health care nurses. The theoretical model is an integration of the findings of empirical research related to intent to stay and retention, components of Neal's theory of home health care nursing practice and findings from earlier work to develop an instrument to measure home health care nurses' job satisfaction. The theoretical model identifies antecedents to job satisfaction of home health care nurses. The antecedents are intrinsic and extrinsic job characteristics. The model also proposes that job satisfaction is directly related to retention and indirectly related to retention though intent to stay. Individual nurse characteristics are indirectly related to retention through intent to stay. The individual characteristic of tenure is indirectly related to retention through autonomy, as an intrinsic characteristic of job satisfaction, and intent to stay. The proposed model can be used to guide research that explores gaps in knowledge about intent to stay and retention among home health care nurses.

Earlier Mother's Age at Menarche Predicts Rapid Infancy Growth and Childhood Obesity

PubMed Central

Ong, Ken K; Northstone, Kate; Wells, Jonathan CK; Rubin, Carol; Ness, Andy R; Golding, Jean; Dunger, David B

2007-01-01

Background Early menarche tends to be preceded by rapid infancy weight gain and is associated with increased childhood and adult obesity risk. As age at menarche is a heritable trait, we hypothesised that age at menarche in the mother may in turn predict her children's early growth and obesity risk. Methods and Findings We tested associations between mother's age at menarche, mother's adult body size and obesity risk, and her children's growth and obesity risk in 6,009 children from the UK population-based Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort who had growth and fat mass at age 9 y measured by dual-energy X-ray absorptiometry. A subgroup of 914 children also had detailed infancy and childhood growth data. In the mothers, earlier menarche was associated with shorter adult height (by 0.64 cm/y), increased weight (0.92 kg/y), and body mass index (BMI, 0.51 kg/m2/y; all p < 0.001). In contrast, in her children, earlier mother's menarche predicted taller height at 9 y (by 0.41 cm/y) and greater weight (0.80 kg/y), BMI (0.29 kg/m2/y), and fat mass index (0.22 kg/m2/year; all p < 0.001). Children in the earliest mother's menarche quintile (≤11 y) were more obese than the oldest quintile (≥15 y) (OR, 2.15, 95% CI 1.46 to 3.17; p < 0.001, adjusted for mother's education and BMI). In the subgroup, children in the earliest quintile showed faster gains in weight (p < 0.001) and height (p < 0.001) only from birth to 2 y, but not from 2 to 9 y (p = 0.3–0.8). Conclusions Earlier age at menarche may be a transgenerational marker of a faster growth tempo, characterised by rapid weight gain and growth, particularly during infancy, and leading to taller childhood stature, but likely earlier maturation and therefore shorter adult stature. This growth pattern confers increased childhood and adult obesity risks. PMID:17455989

Earlier time to aerobic exercise is associated with faster recovery following acute sport concussion

PubMed Central

Richards, Doug; Comper, Paul; Hutchison, Michael G.

2018-01-01

Objective To determine whether earlier time to initiation of aerobic exercise following acute concussion is associated with time to full return to (1) sport and (2) school or work. Methods A retrospective stratified propensity score survival analysis of acute (≤14 days) concussion was used to determine whether time (days) to initiation of aerobic exercise post-concussion was associated with, both, time (days) to full return to (1) sport and (2) school or work. Results A total of 253 acute concussions [median (IQR) age, 17.0 (15.0–20.0) years; 148 (58.5%) males] were included in this study. Multivariate Cox regression models identified that earlier time to aerobic exercise was associated with faster return to sport and school/work adjusting for other covariates, including quintile propensity strata. For each successive day in delay to initiation of aerobic exercise, individuals had a less favourable recovery trajectory. Initiating aerobic exercise at 3 and 7 days following injury was associated with a respective 36.5% (HR, 0.63; 95% CI, 0.53–0.76) and 73.2% (HR, 0.27; 95% CI, 0.16–0.45) reduced probability of faster full return to sport compared to within 1 day; and a respective 45.9% (HR, 0.54; 95% CI, 0.44–0.66) and 83.1% (HR, 0.17; 95% CI, 0.10–0.30) reduced probability of faster full return to school/work. Additionally, concussion history, symptom severity, LOC deleteriously influenced concussion recovery. Conclusion Earlier initiation of aerobic exercise was associated with faster full return to sport and school or work. This study provides greater insight into the benefits and safety of aerobic exercise within the first week of the injury. PMID:29668716

Factors associated with late diagnosis of HIV infection and missed opportunities for earlier testing.

PubMed

Gullón, Alejandra; Verdejo, José; de Miguel, Rosa; Gómez, Ana; Sanz, Jesús

2016-10-01

Late diagnosis (LD) of human immunodeficiency virus (HIV) infection continues to be a significant problem that increases disease burden both for patients and for the public health system. Guidelines have been updated in order to facilitate earlier HIV diagnosis, introducing "indicator condition-guided HIV testing". In this study, we analysed the frequency of LD and associated risk factors. We retrospectively identified those cases that could be considered missed opportunities for an earlier diagnosis. All patients newly diagnosed with HIV infection who attended Hospital La Princesa, Madrid (Spain) between 2007 and 2014 were analysed. We collected epidemiological, clinical and immunological data. We also reviewed electronic medical records from the year before the HIV diagnosis to search for medical consultations due to clinical indicators. HIV infection was diagnosed in 354 patients. The median CD4 count at presentation was 352 cells/mm(3). Overall, 158 patients (50%) met the definition of LD, and 97 (30.7%) the diagnosis of advanced disease. LD was associated with older age and was more frequent amongst immigrants. Heterosexual relations and injection drug use were more likely to be the reasons for LD than relations between men who have sex with men. During the year preceding the diagnosis, 46.6% of the patients had sought medical advice owing to the presence of clinical indicators that should have led to HIV testing. Of those, 24 cases (14.5%) were classified as missed opportunities for earlier HIV diagnosis because testing was not performed. According to these results, all health workers should pursue early HIV diagnosis through the proper implementation of HIV testing guidelines. Such an approach would prove directly beneficial to the patient and indirectly beneficial to the general population through the reduction in the risk of transmission.

Local lung deposition of ultrafine particles in healthy adults: experimental results and theoretical predictions

PubMed Central

2016-01-01

Background Ultrafine particles (UFP) of biogenic and anthropogenic origin occur in high numbers in the ambient atmosphere. In addition, aerosols containing ultrafine powders are used for the inhalation therapy of various diseases. All these facts make it necessary to obtain comprehensive knowledge regarding the exact behavior of UFP in the respiratory tract. Methods Theoretical simulations of local UFP deposition are based on previously conducted inhalation experiments, where particles with various sizes (0.04, 0.06, 0.08, and 0.10 µm) were administered to the respiratory tract by application of the aerosol bolus technique. By the sequential change of the lung penetration depth of the inspired bolus, different volumetric lung regions could be generated and particle deposition in these regions could be evaluated. The model presented in this contribution adopted all parameters used in the experiments. Besides the obligatory comparison between practical and theoretical data, also advanced modeling predictions including the effect of varying functional residual capacity (FRC) and respiratory flow rate were conducted. Results Validation of the UFP deposition model shows that highest deposition fractions occur in those volumetric lung regions corresponding to the small and partly alveolated airways of the tracheobronchial tree. Particle deposition proximal to the trachea is increased in female probands with respect to male subjects. Decrease of both the FRC and the respiratory flow rate results in an enhancement of UFP deposition. Conclusions The study comes to the conclusion that deposition of UFP taken up via bolus inhalation is influenced by a multitude of factors, among which lung morphometry and breathing conditions play a superior role. PMID:27942511

Delusions and underlying needs in older adults with Alzheimer's disease: influence of earlier life experiences and the current environment.

PubMed

Wang, Jing-Jy; Cheng, Wen-Yun; Lai, Pei-Ru; Pai, Ming-Chyi

2014-12-01

Delusions are one of the most severe psychiatric symptoms of individuals with Alzheimer's disease (AD), which often increase the stress experienced by caregivers. The purpose of this study was to understand the influences of earlier life experiences and the current environment on delusions, as well as the underlying needs of older adults with AD who experience delusions. Using an exploratory research design with a qualitative approach and purposive sampling, 20 family caregivers were interviewed. Two psychosocial types of attributes of delusion were categorized: Type A, the influence of earlier life experiences; and Type B, current environmental influences. The underlying needs of those with delusions include physical comfort, a desire to be secure, and a sense of belonging. The contents of delusions are easily influenced by patients' earlier negative experiences and responsibilities, whereas the current environment exerts a crucial influence on the occurrence, frequency, and severity of specific delusions. These results can facilitate planning for patient-centered care by enhancing health care providers' understanding of the psychosocial and environmental attributes and needs behind delusions. Copyright 2014, SLACK Incorporated.

Identified research directions for using manufacturing knowledge earlier in the product lifecycle

PubMed Central

Hedberg, Thomas D.; Hartman, Nathan W.; Rosche, Phil; Fischer, Kevin

2016-01-01

Design for Manufacturing (DFM), especially the use of manufacturing knowledge to support design decisions, has received attention in the academic domain. However, industry practice has not been studied enough to provide solutions that are mature for industry. The current state of the art for DFM is often rule-based functionality within Computer-Aided Design (CAD) systems that enforce specific design requirements. That rule-based functionality may or may not dynamically affect geometry definition. And, if rule-based functionality exists in the CAD system, it is typically a customization on a case-by-case basis. Manufacturing knowledge is a phrase with vast meanings, which may include knowledge on the effects of material properties decisions, machine and process capabilities, or understanding the unintended consequences of design decisions on manufacturing. One of the DFM questions to answer is how can manufacturing knowledge, depending on its definition, be used earlier in the product lifecycle to enable a more collaborative development environment? This paper will discuss the results of a workshop on manufacturing knowledge that highlights several research questions needing more study. This paper proposes recommendations for investigating the relationship of manufacturing knowledge with shape, behavior, and context characteristics of product to produce a better understanding of what knowledge is most important. In addition, the proposal includes recommendations for investigating the system-level barriers to reusing manufacturing knowledge and how model-based manufacturing may ease the burden of knowledge sharing. Lastly, the proposal addresses the direction of future research for holistic solutions of using manufacturing knowledge earlier in the product lifecycle. PMID:27990027

Identified research directions for using manufacturing knowledge earlier in the product lifecycle.

PubMed

Hedberg, Thomas D; Hartman, Nathan W; Rosche, Phil; Fischer, Kevin

2017-01-01

Design for Manufacturing (DFM), especially the use of manufacturing knowledge to support design decisions, has received attention in the academic domain. However, industry practice has not been studied enough to provide solutions that are mature for industry. The current state of the art for DFM is often rule-based functionality within Computer-Aided Design (CAD) systems that enforce specific design requirements. That rule-based functionality may or may not dynamically affect geometry definition. And, if rule-based functionality exists in the CAD system, it is typically a customization on a case-by-case basis. Manufacturing knowledge is a phrase with vast meanings, which may include knowledge on the effects of material properties decisions, machine and process capabilities, or understanding the unintended consequences of design decisions on manufacturing. One of the DFM questions to answer is how can manufacturing knowledge, depending on its definition, be used earlier in the product lifecycle to enable a more collaborative development environment? This paper will discuss the results of a workshop on manufacturing knowledge that highlights several research questions needing more study. This paper proposes recommendations for investigating the relationship of manufacturing knowledge with shape, behavior, and context characteristics of product to produce a better understanding of what knowledge is most important. In addition, the proposal includes recommendations for investigating the system-level barriers to reusing manufacturing knowledge and how model-based manufacturing may ease the burden of knowledge sharing. Lastly, the proposal addresses the direction of future research for holistic solutions of using manufacturing knowledge earlier in the product lifecycle.

Advanced seasonal reproductive development in a male urban bird is reflected in earlier plasma luteinizing hormone rise but not energetic status.

PubMed

Davies, Scott; Behbahaninia, Hirbod; Giraudeau, Mathieu; Meddle, Simone L; Waites, Kyle; Deviche, Pierre

2015-12-01

Urban animals inhabit an environment considerably different than do their non-urban conspecifics, and to persist urban animals must adjust to these novel environments. The timing of seasonal reproductive development (i.e., growth of gonads and secondary sex organs) is a fundamental determinant of the breeding period and is frequently advanced in urban bird populations. However, the underlying mechanism(s) by which birds adjust the timing of reproductive development to urban areas remain(s) largely unknown. Here, we compared the timing of vernal reproductive development in free-ranging urban and non-urban male Abert's Towhees, Melozone aberti, in Phoenix, Arizona, USA, and tested the non-mutually exclusive hypotheses that earlier reproductive development is due to improved energetic status and/or earlier increase in endocrine activity of the reproductive system. We found that urban birds initiated testicular development earlier than non-urban birds, but this disparity was not associated with differences in body condition, fat stores, or innate immune performance. These results provide no support for the hypothesis that energetic constraints are responsible for delayed reproductive development of non-urban relative to urban male Abert's Towhees. Urban birds did, however, increase their plasma luteinizing hormone, but not plasma testosterone, earlier than non-urban birds. These findings suggest that adjustment to urban areas by Abert's Towhees involves increases in the endocrine activity of the anterior pituitary gland and/or hypothalamus earlier than non-urban towhees. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Theoretical results for fully flooded, elliptical hydrodynamic contacts

NASA Technical Reports Server (NTRS)

Hamrock, B. J.; Dowson, D.

1982-01-01

The influence of the ellipticity parameter and the dimensionless speed, load, and materials parameters on minimum film thickness was investigated. The ellipticity parameter was varied from 1 (a ball-on-plate configuration) to 8 (a configuration approaching a line contact). The dimensionless speed parameter was varied over a range of nearly two orders of magnitude. Conditions corresponding to the use of solid materials of bronze, steel, and silicon nitride and lubricants of praffinic and naphthemic mineral oils were considered in obtaining the exponent in the dimensionless materials parameter. Thirty-four different cases were used in obtaining the minimum film thickness formula H min = 3.63U to the 0.68 power G to the 0.49 power W to the -0.073 power 1-e to the 0.68K power). A simplified expression for the ellipticity parameter was found where k = 1.03 (r(y)/r(x)) to the 0.64 power. Contour plots were also shown which indicate in detail the pressure spike and two side lobes in which the minimum film thickness occurs. These theoretical solutions of film thickness have all the essential features of the previously reported experimental observations based upon optical interferometry.

Theoretical results on fractionally integrated exponential generalized autoregressive conditional heteroskedastic processes

NASA Astrophysics Data System (ADS)

Lopes, Sílvia R. C.; Prass, Taiane S.

2014-05-01

Here we present a theoretical study on the main properties of Fractionally Integrated Exponential Generalized Autoregressive Conditional Heteroskedastic (FIEGARCH) processes. We analyze the conditions for the existence, the invertibility, the stationarity and the ergodicity of these processes. We prove that, if { is a FIEGARCH(p,d,q) process then, under mild conditions, { is an ARFIMA(q,d,0) with correlated innovations, that is, an autoregressive fractionally integrated moving average process. The convergence order for the polynomial coefficients that describes the volatility is presented and results related to the spectral representation and to the covariance structure of both processes { and { are discussed. Expressions for the kurtosis and the asymmetry measures for any stationary FIEGARCH(p,d,q) process are also derived. The h-step ahead forecast for the processes {, { and { are given with their respective mean square error of forecast. The work also presents a Monte Carlo simulation study showing how to generate, estimate and forecast based on six different FIEGARCH models. The forecasting performance of six models belonging to the class of autoregressive conditional heteroskedastic models (namely, ARCH-type models) and radial basis models is compared through an empirical application to Brazilian stock market exchange index.

Misleading Theoretical Assumptions in Hypertext/Hypermedia Research.

ERIC Educational Resources Information Center

Tergan, Sigmar-Olaf

1997-01-01

Reviews basic theoretical assumptions of research on learning with hypertext/hypermedia. Focuses on whether the results of research on hypertext/hypermedia-based learning support these assumptions. Results of empirical studies and theoretical analysis reveal that many research approaches have been misled by inappropriate theoretical assumptions on…

Economic Costs Avoided by Diagnosing Melanoma Six Months Earlier Justify >100 Benign Biopsies.

PubMed

Aires, Daniel J; Wick, Jo; Shaath, Tarek S; Rajpara, Anand N; Patel, Vikas; Badawi, Ahmed H; Li, Cicy; Fraga, Garth R; Doolittle, Gary; Liu, Deede Y

2016-05-01

New melanoma drugs bring enormous benefits but do so at significant costs. Because melanoma grows deeper and deadlier over time, deeper lesions are costlier due to increased sentinel lymph node biopsy, chemotherapy, and disease-associated income loss. Prior studies have justified pigmented lesion biopsies on a "value per life" basis; by contrast we sought to assess how many biopsies are justified per melanoma found on a purely economic basis. We modeled how melanomas in the United States would behave if diagnosis were delayed by 6 months, eg, not biopsied, only observed until the next surveillance visit. Economic loss from delayed biopsy is the obverse of economic benefit of performing biopsy earlier. Growth rates were based on Liu et al. The results of this study can be applied to all patients presenting to dermatologists with pigmented skin lesions suspicious for melanoma. In-situ melanomas were excluded because no studies to date have modeled growth rates analogous to those for invasive melanoma. We assume conservatively that all melanomas not biopsied initially will be biopsied and treated 6 months later. Major modeled costs are (1) increased sentinel lymph node biopsy, (2) increased chemotherapy for metastatic lesions using increased 5-yr death as metastasis marker, and (3) income loss per melanoma death at $413,370 as previously published. Costs avoided by diagnosing melanoma earlier justify 170 biopsies per melanoma found. Efforts to penalize "unnecessary" biopsies may be economically counterproductive.

J Drugs Dermatol. 2016;15(5):527-532.

New strings for old Veneziano amplitudes. II. Group-theoretic treatment

NASA Astrophysics Data System (ADS)

Kholodenko, A. L.

2006-09-01

In this part of our four parts work we use theory of polynomial invariants of finite pseudo-reflection groups in order to reconstruct both the Veneziano and Veneziano-like (tachyon-free) amplitudes and the generating function reproducing these amplitudes. We demonstrate that such generating function and amplitudes associated with it can be recovered with help of finite dimensional exactly solvableN=2 supersymmetric quantum mechanical model known earlier from works of Witten, Stone and others. Using the Lefschetz isomorphism theorem we replace traditional supersymmetric calculations by the group-theoretic thus solving the Veneziano model exactly using standard methods of representation theory. Mathematical correctness of our arguments relies on important theorems by Shepard and Todd, Serre and Solomon proven respectively in the early 50s and 60s and documented in the monograph by Bourbaki. Based on these theorems, we explain why the developed formalism leaves all known results of conformal field theories unchanged. We also explain why these theorems impose stringent requirements connecting analytical properties of scattering amplitudes with symmetries of space-time in which such amplitudes act.

An earlier age of breast cancer diagnosis related to more frequent use of antiperspirants/deodorants and underarm shaving.

PubMed

McGrath, K G

2003-12-01

Breast cancer incidence suggests a lifestyle cause. A lifestyle factor used near the breast is the application of antiperspirants/deodorants accompanied by axillary shaving. A previous study did not support a link with breast cancer. If these habits have a role in breast cancer development, women using antiperspirants/deodorants and shaving their underarms frequently would be expected to have an earlier age of diagnosis than those doing so less often. An earlier age of diagnosis would also be expected in those starting to use deodorants and shaving at an earlier age. This is the first study to investigate the intensity of underarm exposure in a cohort of breast cancer survivors. Four hundred and thirty-seven females diagnosed with breast cancer were surveyed. Once grouped by their frequency of underarm hygiene habits, the mean age of diagnosis was the primary end point. Secondary end points included the overall frequency of these habits, and potential usage group confounding variables were evaluated. All statistical tests were two-sided. Frequency and earlier onset of antiperspirant/deodorant usage with underarm shaving were associated with an earlier age of breast cancer diagnosis. Combined habits are likely for this earlier age of diagnosis. In conclusion, underarm shaving with antiperspirant/deodorant use may play a role in breast cancer. It is not clear which of these components are involved. Reviewed literature insinuates absorption of aluminium salts facilitated by dermal barrier disruption. Case-controlled investigations are needed before alternative underarm hygiene habits are suggested.

Antiretroviral treatment-based cost saving interventions may offset expenses for new patients and earlier treatment start.

PubMed

Angeletti, C; Pezzotti, P; Antinori, A; Mammone, A; Navarra, A; Orchi, N; Lorenzini, P; Mecozzi, A; Ammassari, A; Murachelli, S; Ippolito, G; Girardi, E

2014-03-01

Combination antiretroviral therapy (cART) has become the main driver of total costs of caring for persons living with HIV (PLHIV). The present study estimated the short/medium-term cost trends in response to the recent evolution of national guidelines and regional therapeutic protocols for cART in Italy. We developed a deterministic mathematical model that was calibrated using epidemic data for Lazio, a region located in central Italy with about six million inhabitants. In the Base Case Scenario, the estimated number of PLHIV in the Lazio region increased over the period 2012-2016 from 14 414 to 17 179. Over the same period, the average projected annual cost for treating the HIV-infected population was €147.0 million. An earlier cART initiation resulted in a rise of 2.3% in the average estimated annual cost, whereas an increase from 27% to 50% in the proportion of naïve subjects starting cART with a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen resulted in a reduction of 0.3%. Simplification strategies based on NNRTIs co-formulated in a single tablet regimen and protease inhibitor/ritonavir-boosted monotherapy produced an overall reduction in average annual costs of 1.5%. A further average saving of 3.3% resulted from the introduction of generic antiretroviral drugs. In the medium term, cost saving interventions could finance the increase in costs resulting from the inertial growth in the number of patients requiring treatment and from the earlier treatment initiation recommended in recent guidelines. © 2013 British HIV Association.

Diagnosis of varicoceles in men undergoing vasectomy may lead to earlier detection of hypogonadism.

PubMed

Liu, Joceline S; Jones, Madeline; Casey, Jessica T; Fuchs, Amanda B; Cashy, John; Lin, William W

2014-06-01

To determine the temporal relationship between vasectomy, varicocele, and hypogonadism diagnosis. Many young men undergo their first thorough genitourinary examination in their adult lives at the time of vasectomy consultation, providing a unique opportunity for diagnosis of asymptomatic varicoceles. Varicoceles have recently been implicated as a possible reversible contributor to hypogonadism. Hypogonadism may be associated with significant adverse effect, including decreased libido, impaired cognitive function, and increased cardiovascular events. Early diagnosis and treatment of hypogonadism may prevent these adverse sequelae. Data were collected from the Truven Health Analytics MarketScan database, a large outpatient claims database. We reviewed records between 2003 and 2010 for male patients between the ages of 25 and 50 years with International Classification of Diseases, Ninth Revision codes for hypogonadism, vasectomy, and varicocele, and queried dates of first claim. A total of 15,679 men undergoing vasectomies were matched with 156,790 men with nonvasectomy claims in the same year. Vasectomy patients were diagnosed with varicocele at an earlier age (40.9 vs 42.5 years; P=.009). We identified 224,817 men between the ages of 25 and 50 years with a claim of hypogonadism, of which 5883 (2.6%) also had a claim of varicocele. Men with hypogonadism alone were older at presentation compared with men with an accompanying varicocele (41.3 [standard deviation±6.5] vs 34.9 [standard deviation±6.1]; P<.001). Men undergoing vasectomies are diagnosed with varicoceles at a younger age than age-matched controls. Men with varicoceles present with hypogonadism earlier than men without varicoceles. Earlier diagnosis of varicocele at the time of vasectomy allows for earlier detection of hypogonadism. Copyright © 2014 Elsevier Inc. All rights reserved.

A reversal of the shift towards earlier spring phenology in several Mediterranean reptiles and amphibians during the 1998-2013 warming slowdown.

PubMed

Prodon, Roger; Geniez, Philippe; Cheylan, Marc; Devers, Florence; Chuine, Isabelle; Besnard, Aurelien

2017-12-01

Herps, especially amphibians, are particularly susceptible to climate change, as temperature tightly controls many parameters of their biological cycle-above all, their phenology. The timing of herps' activity or migration period-in particular the dates of their first appearance in spring and first breeding-and the shift to earlier dates in response to warming since the last quarter of the 20 th century has often been described up to now as a nearly monotonic trend towards earlier phenological events. In this study, we used citizen science data opportunistically collected on reptiles and amphibians in the northern Mediterranean basin over a period of 32 years to explore temporal variations in herp phenology. For 17 common species, we measured shifts in the date of the species' first spring appearance-which may be the result of current changes in climate-and regressed the first appearance date against temperatures and precipitations. Our results confirmed the expected overall trend towards earlier first spring appearances from 1983 to 1997, and show that the first appearance date of both reptiles and amphibians fits well with the temperature in late winter. However, the trend towards earlier dates was stopped or even reversed in most species between 1998 and 2013. We interpret this reversal as a response to cooling related to the North Atlantic Oscillation (NAO) in the late winter and early spring. During the positive NAO episodes, for certain species only (mainly amphibians), the effect of a warm weather, which tends to advance the phenology, seems to be counterbalanced by the adverse effects of the relative dryness. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Earlier parental set bedtimes as a protective factor against depression and suicidal ideation.

PubMed

Gangwisch, James E; Babiss, Lindsay A; Malaspina, Dolores; Turner, J Blake; Zammit, Gary K; Posner, Kelly

2010-01-01

To examine the relationships between parental set bedtimes, sleep duration, and depression as a quasi-experiment to explore the potentially bidirectional relationship between short sleep duration and depression. Short sleep duration has been shown to precede depression, but this could be explained as a prodromal symptom of depression. Depression in an adolescent can affect his/her chosen bedtime, but it is less likely to affect a parent's chosen set bedtime which can establish a relatively stable upper limit that can directly affect sleep duration. Multivariate cross-sectional analyses of the ADD Health using logistic regression. United States nationally representative, school-based, probability-based sample in 1994-96. Adolescents (n = 15,659) in grades 7 to 12. Adolescents with parental set bedtimes of midnight or later were 24% more likely to suffer from depression (OR = 1.24, 95% CI 1.04-1.49) and 20% more likely to have suicidal ideation (1.20, 1.01-1.41) than adolescents with parental set bedtimes of 10:00 PM or earlier, after controlling for covariates. Consistent with sleep duration and perception of getting enough sleep acting as mediators, the inclusion of these variables in the multivariate models appreciably attenuated the associations for depression (1.07, 0.88-1.30) and suicidal ideation (1.09, 0.92-1.29). The results from this study provide new evidence to strengthen the argument that short sleep duration could play a role in the etiology of depression. Earlier parental set bedtimes could therefore be protective against adolescent depression and suicidal ideation by lengthening sleep duration.

Theoretical model predictions and experimental results for a wavelength switchable Tm:YAG laser.

PubMed

Niu, Yanxiong; Wang, Caili; Liu, Wenwen; Niu, Haisha; Xu, Bing; Man, Da

2014-07-01

We present a theoretical model study of a quasi-three-level laser with particular attention given to the Tm:YAG laser. The oscillating conditions of this laser were theoretically analyzed from the point of the pump threshold while taking into account reabsorption loss. The laser oscillation at 2.02 μm with large stimulated emission sections was suppressed by selecting the appropriate coating for the cavity mirrors, then an efficient laser-diode side-pumped continuous-wave Tm:YAG crystal laser operating at 2.07 μm was realized. Experiments with the Tm:YAG laser confirmed the accuracy of the model, and the model was able to accurately predict that the high Stark sub-level within the H3₆ ground state manifold has a low laser threshold and long laser wavelength, which was achieved by decreasing the transmission of the output coupler.

Earlier Right Ventricular Pacing in Cardiac Resynchronization Therapy for a Patient with Right Axis Deviation.

PubMed

Hattori, Yusuke; Ishibashi, Kohei; Noda, Takashi; Okamura, Hideo; Kanzaki, Hideaki; Anzai, Toshihisa; Yasuda, Satoshi; Kusano, Kengo

2017-09-01

We describe the case of a 37-year-old woman who presented with complete right bundle branch block and right axis deviation. She was admitted to our hospital due to severe heart failure and was dependent on inotropic agents. Cardiac resynchronization therapy was initiated but did not improve her condition. After the optimization of the pacing timing, we performed earlier right ventricular pacing, which led to an improvement of her heart failure. Earlier right ventricular pacing should be considered in patients with complete right bundle branch block and right axis deviation when cardiac resynchronization therapy is not effective.

Theoretical Mathematics

NASA Astrophysics Data System (ADS)

Stöltzner, Michael

Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.

Total deposition of ultrafine particles in the lungs of healthy men and women: experimental and theoretical results

PubMed Central

2016-01-01

Background Inhaled ultrafine particles (UFP) may induce greater adverse respiratory effects than larger particles occurring in the ambient atmosphere. Due to this potential of UFP to act as triggers for diverse lung injuries medical as well as physical research has been increasingly focused on the exact deposition behavior of the particles in lungs of various probands. Main purpose of the present study was the presentation of experimental and theoretical data of total, regional, and local UFP deposition in the lungs of men and women. Methods Both experiments and theoretical simulations were carried out by using particle sizes of 0.04, 0.06, 0.08, and 0.10 µm [number median diameters (NMD)]. Inhalation of UFP took place by application of predefined tidal volumes (500, 750, and 1,000 mL) and respiratory flow rates (150, 250, 375, and 500 mL·s−1). For male subjects a functional residual capacity (FRC) of 3,911±892 mL was measured, whereas female probands had a FRC of 3,314±547 mL. Theoretical predictions were based on (I) a stochastic model of the tracheobronchial tree; (II) particle transport computations according to a random walk algorithm; and (III) empirical formulae for the description of UFP deposition. Results Total deposition fractions (TDF) are marked by a continuous diminution with increasing particle size. Whilst particles measuring 0.04 µm in size deposit in the respiratory tract by 40–70%, particles with a size of 0.10 µm exhibit deposition values ranging from 20% to 45%. Except for the largest particles studied here TDF of female probands are higher than those obtained for male probands. Differences between experimental and theoretical results are most significant for 0.10 µm particles, but never exceed 20%. Predictions of regional (extrathoracic, tracheobronchial, alveolar) UFP deposition show clearly that females tend to develop higher tracheobronchial and alveolar deposition fractions than males. This discrepancy is also confirmed by

A Theoretical Analysis of a New Polarimetric Optical Scheme for Glucose Sensing in the Human Eye

NASA Technical Reports Server (NTRS)

Rovati, Luigi L.; Boeckle, Stefan; Ansari, Rafat R.; Salzman, Jack A. (Technical Monitor)

2002-01-01

The challenging task of in vivo polarimetric glucose sensing is the identification and selection of a scheme to optically access the aqueous humor of the human eye. In this short communication an earlier approach of Cote et al. is theoretically compared with our new optical scheme. Simulations of the new scheme using the eye model of Navarro, suggest that the new optical geometry can overcome the limitations of the previous approach for in vivo measurements of glucose in a human eye.

A formula for calculating theoretical photoelectron fluxes resulting from the He/+/ 304 A solar spectral line

NASA Technical Reports Server (NTRS)

Richards, P. G.; Torr, D. G.

1981-01-01

A simplified method for the evaluation of theoretical photoelectron fluxes in the upper atmosphere resulting from the solar radiation at 304 A is presented. The calculation is based on considerations of primary and cascade (secondary) photoelectron production in the two-stream model, where photoelectron transport is described by two electron streams, one moving up and one moving down, and of loss rates due to collisions with neutral gases and thermal electrons. The calculation is illustrated for the case of photoelectrons at an energy of 24.5 eV, and it is noted that the 24.5-eV photoelectron flux may be used to monitor variations in the solar 304 A flux. Theoretical calculations based on various ionization and excitation cross sections of Banks et al. (1974) are shown to be in generally good agreement with AE-E measurements taken between 200 and 235 km, however the use of more recent, larger cross sections leads to photoelectron values a factor of two smaller than observations but in agreement with previous calculations. It is concluded that a final resolution of the photoelectron problem may depend on a reevaluation of the inelastic electron collision cross sections.

Local lung deposition of ultrafine particles in healthy adults: experimental results and theoretical predictions.

PubMed

Sturm, Robert

2016-11-01

Ultrafine particles (UFP) of biogenic and anthropogenic origin occur in high numbers in the ambient atmosphere. In addition, aerosols containing ultrafine powders are used for the inhalation therapy of various diseases. All these facts make it necessary to obtain comprehensive knowledge regarding the exact behavior of UFP in the respiratory tract. Theoretical simulations of local UFP deposition are based on previously conducted inhalation experiments, where particles with various sizes (0.04, 0.06, 0.08, and 0.10 µm) were administered to the respiratory tract by application of the aerosol bolus technique. By the sequential change of the lung penetration depth of the inspired bolus, different volumetric lung regions could be generated and particle deposition in these regions could be evaluated. The model presented in this contribution adopted all parameters used in the experiments. Besides the obligatory comparison between practical and theoretical data, also advanced modeling predictions including the effect of varying functional residual capacity (FRC) and respiratory flow rate were conducted. Validation of the UFP deposition model shows that highest deposition fractions occur in those volumetric lung regions corresponding to the small and partly alveolated airways of the tracheobronchial tree. Particle deposition proximal to the trachea is increased in female probands with respect to male subjects. Decrease of both the FRC and the respiratory flow rate results in an enhancement of UFP deposition. The study comes to the conclusion that deposition of UFP taken up via bolus inhalation is influenced by a multitude of factors, among which lung morphometry and breathing conditions play a superior role.

Earlier versus later continuous Kangaroo Mother Care (KMC) for stable low-birth-weight infants: a randomized controlled trial.

PubMed

Nagai, S; Andrianarimanana, D; Rabesandratana, N; Yonemoto, N; Nakayama, T; Mori, R

2010-06-01

The aim of this study was to examine the effectiveness of earlier continuous Kangaroo Mother Care (KMC) for relatively stable low-birth-weight (LBW) infants in a resource-limited country. A randomized controlled trial was performed in LBW infants at a referral hospital in Madagascar. Earlier continuous KMC (intervention) was begun as soon as possible, within 24 h postbirth, and later continuous KMC (control: conventional care) was begun after complete stabilization (generally after 24 h postbirth). Main outcome measure was mortality during the first 28 days postbirth. This trial was registered with ClinicalTrials.gov, NCT00531492. A total of 73 infants (intervention 37, control 36) were included. Earlier continuous KMC had higher but no statistically different mortality in the first 28 days postbirth (1 vs. 2; risk ratio, 1.95; 95% CIs, 0.18-20.53; p = 1.00). There were no differences in incidence of morbidities. Body weight loss from birth to 24 h postbirth was significantly less in earlier KMC infants compared with later KMC infants. (-34.81 g vs. -73.97 g; mean difference, 39.16 g; 95% CIs, 10.30-68.03; p = 0.01; adjusted p = 0.02). Adverse events and duration of hospitalization were not different between the two groups. Further evaluations of earlier continuous KMC including measurement of KMC dose, are needed in resource-limited countries.

New theoretical results for the Lehmann effect in cholesteric liquid crystals

NASA Technical Reports Server (NTRS)

Brand, Helmut R.; Pleiner, Harald

1988-01-01

The Lehmann effect arising in a cholesteric liquid crystal drop when a temperature gradient is applied parallel to its helical axis is investigated theoretically using a local approach. A pseudoscalar quantity is introduced to allow for cross couplings which are absent in nematic liquid crystals, and the statics and dissipative dynamics are analyzed in detail. It is shown that the Lehmann effect is purely dynamic for the case of an external electric field and purely static for an external density gradient, but includes both dynamic and static coupling contributions for the cases of external temperature or concentration gradients.

A theoretical model of continuity in anxiety and links to academic achievement in disaster-exposed school children.

PubMed

Weems, Carl F; Scott, Brandon G; Taylor, Leslie K; Cannon, Melinda F; Romano, Dawn M; Perry, Andre M

2013-08-01

This study tested a theoretical model of continuity in anxious emotion and its links to academic achievement in disaster-exposed youth. An urban school based sample of youths (n = 191; Grades 4-8) exposed to Hurricane Katrina were assessed at 24 months (Time 1) and then again at 30 months (Time 2) postdisaster. Academic achievement was assessed through end of the school year standardized test scores (~31 months after Katrina). The results suggest that the association of traumatic stress to academic achievement was indirect via linkages from earlier (Time 1) posttraumatic stress disorder symptoms that predicted later (Time 2) test anxiety. Time 2 test anxiety was then negatively associated with academic achievement. Age and gender invariance testing suggested strong consistency across gender and minor developmental variation in the age range examined. The model presented advances the developmental understanding of the expression of anxious emotion and its links to student achievement among disaster-exposed urban school children. The findings highlight the importance of identifying heterotypic continuity in anxiety and suggest potential applied and policy directions for disaster-exposed youth. Avenues for future theoretical refinement are also discussed.

PREFACE: 2nd International Workshop on Theoretical and Computational Physics (IWTCP-2): Modern Methods and Latest Results in Particle Physics, Nuclear Physics and Astrophysics and the 39th National Conference on Theoretical Physics (NCTP-39)

NASA Astrophysics Data System (ADS)

Hoang, Trinh Xuan; Ky, Nguyen Anh; Lan, Nguyen Tri; Viet, Nguyen Ai

2015-06-01

This volume contains selected papers presented at the 2nd International Workshop on Theoretical and Computational Physics (IWTCP-2): Modern Methods and Latest Results in Particle Physics, Nuclear Physics and Astrophysics and the 39th National Conference on Theoretical Physics (NCTP-39). Both the workshop and the conference were held from 28th - 31st July 2014 in Dakruco Hotel, Buon Ma Thuot, Dak Lak, Vietnam. The NCTP-39 and the IWTCP-2 were organized under the support of the Vietnamese Theoretical Physics Society, with a motivation to foster scientific exchanges between the theoretical and computational physicists in Vietnam and worldwide, as well as to promote high-standard level of research and education activities for young physicists in the country. The IWTCP-2 was also an External Activity of the Asia Pacific Center for Theoretical Physics (APCTP). About 100 participants coming from nine countries participated in the workshop and the conference. At the IWTCP-2 workshop, we had 16 invited talks presented by international experts, together with eight oral and ten poster contributions. At the NCTP-39, three invited talks, 15 oral contributions and 39 posters were presented. We would like to thank all invited speakers, participants and sponsors for making the workshop and the conference successful. Trinh Xuan Hoang, Nguyen Anh Ky, Nguyen Tri Lan and Nguyen Ai Viet

Patient centredness in integrated care: results of a qualitative study based on a systems theoretical framework

PubMed Central

Lüdecke, Daniel

2014-01-01

Introduction Health care providers seek to improve patient-centred care. Due to fragmentation of services, this can only be achieved by establishing integrated care partnerships. The challenge is both to control costs while enhancing the quality of care and to coordinate this process in a setting with many organisations involved. The problem is to establish control mechanisms, which ensure sufficiently consideration of patient centredness. Theory and methods Seventeen qualitative interviews have been conducted in hospitals of metropolitan areas in northern Germany. The documentary method, embedded into a systems theoretical framework, was used to describe and analyse the data and to provide an insight into the specific perception of organisational behaviour in integrated care. Results The findings suggest that integrated care partnerships rely on networks based on professional autonomy in the context of reliability. The relationships of network partners are heavily based on informality. This correlates with a systems theoretical conception of organisations, which are assumed autonomous in their decision-making. Conclusion and discussion Networks based on formal contracts may restrict professional autonomy and competition. Contractual bindings that suppress the competitive environment have negative consequences for patient-centred care. Drawbacks remain due to missing self-regulation of the network. To conclude, less regimentation of integrated care partnerships is recommended. PMID:25411573

Theoretical DFT study on spectroscopic signature and molecular dynamics of neurotransmitter and effect of hydrogen removal

NASA Astrophysics Data System (ADS)

Mukherjee, V.; Singh, N. P.; Yadav, R. A.

2013-04-01

Vibrational spectroscopic study has been made for the serotonin molecule and its deprotonated form. The Infrared and Raman spectra in optimum geometry of these two molecules are calculated using density functional theorem and the normal modes are assigned using potential energy distributions (PEDs) which are calculated using normal coordinate analysis method. The vibrational frequencies of these two molecules are reported and a comparison has been made. The effect of removal of the hydrogen atom from the serotonin molecule upon its geometry and vibrational frequencies are studied. Electronic structures of these two molecules are also studied using natural bond orbital (NBO) analysis. Theoretical Raman spectrum of serotonin at different exciting laser frequencies and at different temperatures are obtained and the results are discussed. Present study reveals that some wrong assignments had been made for serotonin molecule in earlier study.

Economic Analysis in the Pacific Northwest Land Resources Project: Theoretical Considerations and Preliminary Results

NASA Technical Reports Server (NTRS)

Morse, D. R. A.; Sahlberg, J. T.

1977-01-01

The Pacific Northwest Land Resources Inventory Demonstration Project i s an a ttempt to combine a whole spectrum of heterogeneous geographic, institutional and applications elements in a synergistic approach to the evaluation of remote sensing techniques. This diversity is the prime motivating factor behind a theoretical investigation of alternative economic analysis procedures. For a multitude of reasons--simplicity, ease of understanding, financial constraints and credibility, among others--cost-effectiveness emerges as the most practical tool for conducting such evaluation determinatIons in the Pacific Northwest. Preliminary findings in two water resource application areas suggest, in conformity with most published studies, that Lands at-aided data collection methods enjoy substantial cost advantages over alternative techniques. The pntential for sensitivity analysis based on cost/accuracy tradeoffs is considered on a theoretical plane in the absence of current accuracy figures concerning the Landsat-aided approach.

A Review of Quality of Life after Predictive Testing for and Earlier Identification of Neurodegenerative Diseases

PubMed Central

Paulsen, Jane S.; Nance, Martha; Kim, Ji-In; Carlozzi, Noelle E.; Panegyres, Peter K.; Erwin, Cheryl; Goh, Anita; McCusker, Elizabeth; Williams, Janet K.

2013-01-01

The past decade has witnessed an explosion of evidence suggesting that many neurodegenerative diseases can be detected years, if not decades, earlier than previously thought. To date, these scientific advances have not provoked any parallel translational or clinical improvements. There is an urgency to capitalize on this momentum so earlier detection of disease can be more readily translated into improved health-related quality of life for families at risk for, or suffering with, neurodegenerative diseases. In this review, we discuss health-related quality of life (HRQOL) measurement in neurodegenerative diseases and the importance of these “patient reported outcomes” for all clinical research. Next, we address HRQOL following early identification or predictive genetic testing in some neurodegenerative diseases: Huntington disease, Alzheimer's disease, Parkinson's disease, Dementia with Lewy bodies, frontotemporal dementia, amyotrophic lateral sclerosis, prion diseases, hereditary ataxias, Dentatorubral-pallidoluysian atrophy and Wilson's disease. After a brief report of available direct-to-consumer genetic tests, we address the juxtaposition of earlier disease identification with assumed reluctance towards predictive genetic testing. Forty-one studies examining health related outcomes following predictive genetic testing for neurodegenerative disease suggested that (a) extreme or catastrophic outcomes are rare; (b) consequences commonly include transiently increased anxiety and/or depression; (c) most participants report no regret; (d) many persons report extensive benefits to receiving genetic information; and (e) stigmatization and discrimination for genetic diseases are poorly understood and policy and laws are needed. Caution is appropriate for earlier identification of neurodegenerative diseases but findings suggest further progress is safe, feasible and likely to advance clinical care. PMID:24036231

The theoretical background to BS7167: 1990 - specification for Bordeaux connections

NASA Astrophysics Data System (ADS)

Gorley, T. A. E.

1992-03-01

The theoretical background to the specification of Bordeaux connections (components of lifting gear used to join together wire rope and a chain, or two lengths of wire rope, where the joined lengths have to run over a sheave as in the case of grabbing cranes) is documented. Decisions taken in the drafting of earlier specifications are not documented. The design criteria for BS7167:1990 are addressed. The various parts of the Bordeaux connection specified in the standard are discussed in turn: the link portion, the rope portion, and the grab shackle. Some tests on the new design undertaken by the Health and Safety Executive confirm the new design criteria to be adequate for the strengths of rope to be used with this component.

Sharper Graph-Theoretical Conditions for the Stabilization of Complex Reaction Networks

PubMed Central

Knight, Daniel; Shinar, Guy; Feinberg, Martin

2015-01-01

Across the landscape of all possible chemical reaction networks there is a surprising degree of stable behavior, despite what might be substantial complexity and nonlinearity in the governing differential equations. At the same time there are reaction networks, in particular those that arise in biology, for which richer behavior is exhibited. Thus, it is of interest to understand network-structural features whose presence enforces dull, stable behavior and whose absence permits the dynamical richness that might be necessary for life. We present conditions on a network’s Species-Reaction Graph that ensure a high degree of stable behavior, so long as the kinetic rate functions satisfy certain weak and natural constraints. These graph-theoretical conditions are considerably more incisive than those reported earlier. PMID:25600138

Traumatic brain injury history is associated with an earlier age of dementia onset in autopsy-confirmed Alzheimer's disease.

PubMed

Schaffert, Jeff; LoBue, Christian; White, Charles L; Chiang, Hsueh-Sheng; Didehbani, Nyaz; Lacritz, Laura; Rossetti, Heidi; Dieppa, Marisara; Hart, John; Cullum, C Munro

2018-05-01

To evaluate whether a history of traumatic brain injury (TBI) with reported loss of consciousness (LOC) is a risk factor for earlier onset of Alzheimer's disease (AD) in an autopsy-confirmed sample. Data from 2,133 participants with autopsy-confirmed AD (i.e., at least Braak neurofibrillary tangle stages III to VI and CERAD neuritic plaque score moderate to frequent) were obtained from the National Alzheimer's Coordinating Center (NACC). Participants were categorized by presence/absence of self-reported remote (i.e., >1 year prior to their first Alzheimer's Disease Center visit) history of TBI with LOC (TBI+ vs. TBI-). Analyses of Covariance (ANCOVA) controlling for sex, education, and race compared groups on clinician-estimated age of symptom onset and age of diagnosis. Average age of onset was 2.34 years earlier (p = .01) for the TBI+ group (n = 194) versus the TBI- group (n = 1900). Dementia was diagnosed on average 2.83 years earlier (p = .002) in the TBI+ group (n = 197) versus the TBI- group (n = 1936). Using more stringent neuropathological criteria (i.e., Braak stages V-VI and CERAD frequent), both age of AD onset and diagnosis were 3.6 years earlier in the TBI+ group (both p's < .001). History of TBI with reported LOC appears to be a risk factor for earlier AD onset. This is the first study to use autopsy-confirmed cases, supporting previous investigations that used clinical criteria for the diagnosis of AD. Further investigation as to possible underlying mechanisms of association is needed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Total deposition of ultrafine particles in the lungs of healthy men and women: experimental and theoretical results.

PubMed

Sturm, Robert

2016-06-01

Inhaled ultrafine particles (UFP) may induce greater adverse respiratory effects than larger particles occurring in the ambient atmosphere. Due to this potential of UFP to act as triggers for diverse lung injuries medical as well as physical research has been increasingly focused on the exact deposition behavior of the particles in lungs of various probands. Main purpose of the present study was the presentation of experimental and theoretical data of total, regional, and local UFP deposition in the lungs of men and women. Both experiments and theoretical simulations were carried out by using particle sizes of 0.04, 0.06, 0.08, and 0.10 µm [number median diameters (NMD)]. Inhalation of UFP took place by application of predefined tidal volumes (500, 750, and 1,000 mL) and respiratory flow rates (150, 250, 375, and 500 mL·s(-1)). For male subjects a functional residual capacity (FRC) of 3,911±892 mL was measured, whereas female probands had a FRC of 3,314±547 mL. Theoretical predictions were based on (I) a stochastic model of the tracheobronchial tree; (II) particle transport computations according to a random walk algorithm; and (III) empirical formulae for the description of UFP deposition. Total deposition fractions (TDF) are marked by a continuous diminution with increasing particle size. Whilst particles measuring 0.04 µm in size deposit in the respiratory tract by 40-70%, particles with a size of 0.10 µm exhibit deposition values ranging from 20% to 45%. Except for the largest particles studied here TDF of female probands are higher than those obtained for male probands. Differences between experimental and theoretical results are most significant for 0.10 µm particles, but never exceed 20%. Predictions of regional (extrathoracic, tracheobronchial, alveolar) UFP deposition show clearly that females tend to develop higher tracheobronchial and alveolar deposition fractions than males. This discrepancy is also confirmed by airway generation

Earlier Pulmonary Valve Replacement in Down Syndrome Patients Following Tetralogy of Fallot Repair.

PubMed

Sullivan, Rachel T; Frommelt, Peter C; Hill, Garick D

2017-08-01

The association between Down syndrome and pulmonary hypertension could contribute to more severe pulmonary regurgitation after tetralogy of Fallot repair and possibly earlier pulmonary valve replacement. We compared cardiac magnetic resonance measures of pulmonary regurgitation and right ventricular dilation as well as timing of pulmonary valve replacement between those with and without Down syndrome after tetralogy of Fallot repair. Review of our surgical database from 2000 to 2015 identified patients with tetralogy of Fallot with pulmonary stenosis. Those with Down syndrome were compared to those without. The primary outcome of interest was time from repair to pulmonary valve replacement. Secondary outcomes included pulmonary regurgitation and indexed right ventricular volume on cardiac magnetic resonance imaging. The cohort of 284 patients included 35 (12%) with Down syndrome. Transannular patch repair was performed in 210 (74%). Down syndrome showed greater degree of pulmonary regurgitation (55 ± 14 vs. 37 ± 16%, p = 0.01) without a significantly greater rate of right ventricular dilation (p = 0.09). In multivariable analysis, Down syndrome (HR 2.3, 95% CI 1.2-4.5, p = 0.02) and transannular patch repair (HR 5.5, 95% CI 1.7-17.6, p = 0.004) were significant risk factors for valve replacement. Those with Down syndrome had significantly lower freedom from valve replacement (p = 0.03). Down syndrome is associated with an increased degree of pulmonary regurgitation and earlier pulmonary valve replacement after tetralogy of Fallot repair. These patients require earlier assessment by cardiac magnetic resonance imaging to determine timing of pulmonary valve replacement and evaluation for and treatment of preventable causes of pulmonary hypertension.

40 CFR 87.21 - Exhaust emission standards for Tier 4 and earlier engines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Emissions (New Aircraft Gas Turbine Engines) § 87.21 Exhaust emission standards for Tier 4 and earlier... standards. (a) Exhaust emissions of smoke from each new aircraft gas turbine engine of class T8 manufactured... from each new aircraft gas turbine engine of class TF and of rated output of 129 kilonewtons thrust or...

40 CFR 87.21 - Exhaust emission standards for Tier 4 and earlier engines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Emissions (New Aircraft Gas Turbine Engines) § 87.21 Exhaust emission standards for Tier 4 and earlier... standards. (a) Exhaust emissions of smoke from each new aircraft gas turbine engine of class T8 manufactured... from each new aircraft gas turbine engine of class TF and of rated output of 129 kilonewtons thrust or...

A comparison of experimental and theoretical results for labyrinth gas seals with honeycomb stators. M.S. Thesis

NASA Technical Reports Server (NTRS)

Hawkins, Lawrence Allen

1988-01-01

Experimental results for the rotordynamic stiffness and damping coefficients of a labyrinth -rotor honeycomb-stator seal are presented. The coefficients are compared to the coefficients of a labyrinth-rotor smooth-stator seal having the same geometry. The coefficients are compared to analytical results from a two-control-volume compressible flow model. The experimental results show that the honeycomb stator configuration is more stable than the smooth stator configuration at low rotor speeds. At high rotor speeds and low clearance, the smooth stator seal is more stable. The theoretical model predicts the cross-coupled stiffness of the honeycomb stator seal correctly within 25 percent of measured values. The model provides accurate predictions of direct damping for large clearance seals. Overall, the model does not perform as well for low clearance seals as for high clearance seals.

Do emotional support and classroom organization earlier in the year set the stage for higher quality instruction?

PubMed

Curby, Timothy W; Rimm-Kaufman, Sara E; Abry, Tashia

2013-10-01

Many teachers believe that providing greater emotional and organizational supports in the beginning of the year strengthens their ability to teach effectively as the year progresses. Some interventions, such as the Responsive Classroom (RC) approach, explicitly embed this sequence into professional development efforts. We tested the hypothesis that earlier emotional and organizational supports set the stage for improved instruction later in the year in a sample of third- and fourth-grade teachers enrolled in a randomized controlled trial of the RC approach. Further, we examined the extent to which the model generalized for teachers using varying levels of RC practices as well as whether or not teachers were in the intervention or control groups. Teachers' emotional, organizational, and instructional interactions were observed using the Classroom Assessment Scoring System (Pianta, La Paro, & Hamre, 2008) on five occasions throughout the year. Results indicated a reciprocal relation between emotional and instructional supports. Specifically, higher levels of emotional support earlier in the year predicted higher instructional support later in the year. Also, higher levels of instructional support earlier in the year predicted higher emotional support later in the year. Classroom organization was not found to have longitudinal associations with the other domains across a year. This pattern was robust when controlling for the use of RC practices as well as across intervention and control groups. Further, teachers' use of RC practices predicted higher emotional support and classroom organization throughout the year, suggesting the malleability of this teacher characteristic. Discussion highlights the connection between teachers' emotional and instructional supports and how the use of RC practices improves teachers' emotionally supportive interactions with students. Copyright © 2013 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights

Number of Diverticulitis Episodes Before Resection and Factors Associated With Earlier Interventions

PubMed Central

Simianu, Vlad V.; Fichera, Alessandro; Bastawrous, Amir L.; Davidson, Giana H.; Florence, Michael G.; Thirlby, Richard C.; Flum, David R.

2016-01-01

IMPORTANCE Despite professional recommendations to delay elective colon resection for patients with uncomplicated diverticulitis, early surgery (after <3 preceding episodes) appears to be common. Several factors have been suggested to contribute to early surgery, including increasing numbers of younger patients, a lower threshold to operate laparoscopically, and growing recognition of “smoldering” (or nonrecovering) diverticulitis episodes. However, the relevance of these factors in early surgery has not been well tested, and most prior studies have focused on hospitalizations, missing outpatient events and making it difficult to assess guideline adherence in earlier interventions. OBJECTIVE To describe patterns of episodes of diverticulitis before surgery and factors associated with earlier interventions using inpatient, outpatient, and antibiotic prescription claims. DESIGN, SETTING, AND PARTICIPANTS This investigation was a nationwide retrospective cohort study from January 1, 2009, to December 31, 2012. The dates of the analysis were July 2014 to May 2015. Participants were immunocompetent adult patients (age range, 18-64 years) with incident, uncomplicated diverticulitis. EXPOSURE Elective colectomy for diverticulitis. MAIN OUTCOMES AND MEASURES Inpatient, outpatient, and antibiotic prescription claims for diverticulitis captured in the MarketScan (Truven Health Analytics) databases. RESULTS Of 87 461 immunocompetent patients having at least 1 claim for diverticulitis, 6.4% (n = 5604) underwent a resection. The final study cohort comprised 3054 nonimmunocompromised patients who underwent elective resection for uncomplicated diverticulitis, of whom 55.6% (n = 1699) were male. Before elective surgery, they had a mean (SD) of 1.0 (0.9) inpatient claims, 1.5 (1.5) outpatient claims, and 0.5 (1.2) antibiotic prescription claims related to diverticulitis. Resection occurred after fewer than 3 episodes in 94.9% (2897 of 3054) of patients if counting inpatient

Evaluating the Theoretic Adequacy and Applied Potential of Computational Models of the Spacing Effect.

PubMed

Walsh, Matthew M; Gluck, Kevin A; Gunzelmann, Glenn; Jastrzembski, Tiffany; Krusmark, Michael

2018-06-01

The spacing effect is among the most widely replicated empirical phenomena in the learning sciences, and its relevance to education and training is readily apparent. Yet successful applications of spacing effect research to education and training is rare. Computational modeling can provide the crucial link between a century of accumulated experimental data on the spacing effect and the emerging interest in using that research to enable adaptive instruction. In this paper, we review relevant literature and identify 10 criteria for rigorously evaluating computational models of the spacing effect. Five relate to evaluating the theoretic adequacy of a model, and five relate to evaluating its application potential. We use these criteria to evaluate a novel computational model of the spacing effect called the Predictive Performance Equation (PPE). Predictive Performance Equation combines elements of earlier models of learning and memory including the General Performance Equation, Adaptive Control of Thought-Rational, and the New Theory of Disuse, giving rise to a novel computational account of the spacing effect that performs favorably across the complete sets of theoretic and applied criteria. We implemented two other previously published computational models of the spacing effect and compare them to PPE using the theoretic and applied criteria as guides. Copyright © 2018 Cognitive Science Society, Inc.

Sibutramine characterization and solubility, a theoretical study

NASA Astrophysics Data System (ADS)

Aceves-Hernández, Juan M.; Nicolás Vázquez, Inés; Hinojosa-Torres, Jaime; Penieres Carrillo, Guillermo; Arroyo Razo, Gabriel; Miranda Ruvalcaba, René

2013-04-01

Solubility data from sibutramine (SBA) in a family of alcohols were obtained at different temperatures. Sibutramine was characterized by using thermal analysis and X-ray diffraction technique. Solubility data were obtained by the saturation method. The van't Hoff equation was used to obtain the theoretical solubility values and the ideal solvent activity coefficient. No polymorphic phenomena were found from the X-ray diffraction analysis, even though this compound is a racemic mixture of (+) and (-) enantiomers. Theoretical calculations showed that the polarisable continuum model was able to reproduce the solubility and stability of sibutramine molecule in gas phase, water and a family of alcohols at B3LYP/6-311++G (d,p) level of theory. Dielectric constant, dipolar moment and solubility in water values as physical parameters were used in those theoretical calculations for explaining that behavior. Experimental and theoretical results were compared and good agreement was obtained. Sibutramine solubility increased from methanol to 1-octanol in theoretical and experimental results.

Facilitating earlier transfer of care from acute stroke services into the community.

PubMed

Robinson, Jennifer

This article outlines an initiative to reduce length of stay for stroke patients within an acute hospital and to facilitate earlier transfer of care. Existing care provision was remodelled and expanded to deliver stroke care to patients within a community bed-based intermediate care facility or intermediate care at home. This new model of care has improved the delivery of rehabilitation through alternative and innovative ways of addressing service delivery that meet the needs of the patients.

Earlier Snowmelt Changes the Ratio Between Early and Late Season Forest Productivity

NASA Astrophysics Data System (ADS)

Knowles, J. F.; Molotch, N. P.; Trujillo, E.; Litvak, M. E.

2017-12-01

Future projections of declining snowpack and increasing potential evaporation associated with climate warming are predicted to advance the timing of snowmelt in mountain ecosystems globally. This scenario has direct implications for snowmelt-driven forest productivity, but the net effect of temporally shifting moisture dynamics is unknown with respect to the annual carbon balance. Accordingly, this study uses both satellite- and tower-based observations to document the forest productivity response to snowpack and potential evaporation variability between 1989 and 2012 throughout the southern Rocky Mountain ecoregion, USA. These results show that a combination of low snow accumulation and record high potential evaporation in 2012 resulted in the 34-year minimum ecosystem productivity that could be indicative of future conditions. Moreover, early and late season productivity were significantly and inversely related, suggesting that future shifts toward earlier or reduced snowmelt could increase late-season moisture stress to vegetation and thus restrict productivity despite a longer growing season. This relationship was further subject to modification by summer precipitation, and the controls on the early/late season productivity ratio are explored within the context of ecosystem carbon storage in the future. Any perturbation to the carbon cycle at this scale represents a potential feedback to climate change since snow-covered forests represent an important global carbon sink.

Theoretical study on a water muffler

NASA Astrophysics Data System (ADS)

Du, T.; Chen, Y. W.; Miao, T. C.; Wu, D. Z.

2016-05-01

Theoretical computation on a previously studied water muffler is carried out in this article. Structure of the water muffler is composed of two main parts, namely, the Kevlar- reinforced rubber tube and the inner-noise-reduction structure. Rubber wall of the rubber tube is assumed to function as rigid wall lined with sound absorption material and is described by a complex radial wave number. Comparison among the results obtained from theoretical computation, FEM (finite element method) simulation and experiment of the rubber tube and that of the water muffler has been made. The theoretical results show a good accordance in general tendency with the FEM simulated and the measured results. After that, parametric study on the diameter of the inner structure and that of the rubber tube is conducted. Results show that the diameter of the left inner structure has the most significant effect on the SPL of the water muffler due to its location and its effect on the diameter ratio D2/D1.

Praxis and reflexivity for interprofessional education: towards an inclusive theoretical framework for learning.

PubMed

Hutchings, Maggie; Scammell, Janet; Quinney, Anne

2013-09-01

While there is growing evidence of theoretical perspectives adopted in interprofessional education, learning theories tend to foreground the individual, focusing on psycho-social aspects of individual differences and professional identity to the detriment of considering social-structural factors at work in social practices. Conversely socially situated practice is criticised for being context-specific, making it difficult to draw generalisable conclusions for improving interprofessional education. This article builds on a theoretical framework derived from earlier research, drawing on the dynamics of Dewey's experiential learning theory and Archer's critical realist social theory, to make a case for a meta-theoretical framework enabling social-constructivist and situated learning theories to be interlinked and integrated through praxis and reflexivity. Our current analysis is grounded in an interprofessional curriculum initiative mediated by a virtual community peopled by health and social care users. Student perceptions, captured through quantitative and qualitative data, suggest three major disruptive themes, creating opportunities for congruence and disjuncture and generating a model of zones of interlinked praxis associated with professional differences and identity, pedagogic strategies and technology-mediated approaches. This model contributes to a framework for understanding the complexity of interprofessional learning and offers bridges between individual and structural factors for engaging with the enablements and constraints at work in communities of practice and networks for interprofessional education.

Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.

PubMed

Di Forti, Marta; Sallis, Hannah; Allegri, Fabio; Trotta, Antonella; Ferraro, Laura; Stilo, Simona A; Marconi, Arianna; La Cascia, Caterina; Reis Marques, Tiago; Pariante, Carmine; Dazzan, Paola; Mondelli, Valeria; Paparelli, Alessandra; Kolliakou, Anna; Prata, Diana; Gaughran, Fiona; David, Anthony S; Morgan, Craig; Stahl, Daniel; Khondoker, Mizanur; MacCabe, James H; Murray, Robin M

2014-11-01

Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated. We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP. Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16-1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11-1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06-1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users. Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users. © The Author 2013. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Light pollution is associated with earlier tree budburst across the United Kingdom.

PubMed

Ffrench-Constant, Richard H; Somers-Yeates, Robin; Bennie, Jonathan; Economou, Theodoros; Hodgson, David; Spalding, Adrian; McGregor, Peter K

2016-06-29

The ecological impact of night-time lighting is of concern because of its well-demonstrated effects on animal behaviour. However, the potential of light pollution to change plant phenology and its corresponding knock-on effects on associated herbivores are less clear. Here, we test if artificial lighting can advance the timing of budburst in trees. We took a UK-wide 13 year dataset of spatially referenced budburst data from four deciduous tree species and matched it with both satellite imagery of night-time lighting and average spring temperature. We find that budburst occurs up to 7.5 days earlier in brighter areas, with the relationship being more pronounced for later-budding species. Excluding large urban areas from the analysis showed an even more pronounced advance of budburst, confirming that the urban 'heat-island' effect is not the sole cause of earlier urban budburst. Similarly, the advance in budburst across all sites is too large to be explained by increases in temperature alone. This dramatic advance of budburst illustrates the need for further experimental investigation into the impact of artificial night-time lighting on plant phenology and subsequent species interactions. As light pollution is a growing global phenomenon, the findings of this study are likely to be applicable to a wide range of species interactions across the world. © 2016 The Authors.

Sensory, physical and chemical characteristics of cooked ham manufactured from rapidly chilled and earlier deboned M. semimembranosus.

PubMed

Tomović, Vladimir M; Jokanović, Marija R; Petrović, Ljiljana S; Tomović, Mila S; Tasić, Tatjana A; Ikonić, Predrag M; Sumić, Zdravko M; Sojić, Branislav V; Skaljac, Snežana B; Sošo, Milena M

2013-01-01

Effects of rapid chilling of carcasses (at -31°C in the first 3h of chilling, and then at 2-4°C) and earlier deboning (8h post-mortem), compared to rapid (till 24h post-mortem) and conventional chilling (at 2-4°C, till 24h post-mortem), on quality characteristics of pork M. semimebranosus and cooked ham were investigated. Quality measurements included pH value, colour (CIEL a b values) and total aerobic count of M. semimebranosus, as well as sensory (colour, juiciness, texture, and flavour), physical (pH value, colour - CIEL a b values and texture - Warner-Bratzler shear and penetration forces) and chemical (protein, total fat, and moisture content) characteristics of cooked ham. The cooked ham was manufactured from pieces of M. semimebranosus with ultimate lightness (CIEL value) lower than 50. Rapid chilling and earlier deboning significantly increased quantity of M. semimebranosus desirable for cooked ham manufacturing. Earlier start of pork fabrication did not affect important quality characteristics of cooked ham. Copyright © 2012 Elsevier Ltd. All rights reserved.

Trends of earlier palliative care consultation in advanced cancer patients receiving palliative radiation therapy.

PubMed

Chang, Sanders; Sigel, Keith; Goldstein, Nathan E; Wisnivesky, Juan; Dharmarajan, Kavita V

2018-06-06

The American Society of Clinical Oncology recommends that all patients with metastatic disease receive dedicated palliative care (PC) services early in their illness, ideally via interdisciplinary care teams. We investigated the time trends of specialty palliative care consultations from the date of metastatic cancer diagnosis among patients receiving palliative radiation therapy (PRT). A shorter time interval between metastatic diagnosis and first PC consultation suggests earlier involvement of palliative care in a patient's life with metastatic cancer. In this IRB-approved retrospective analysis, patients treated with PRT for solid tumors (bone and brain) at a single tertiary care hospital between 2010 and 2016 were included. Cohorts were arbitrarily established by metastatic diagnosis within approximately two-year intervals: (1) 1/1/2010-3/27/2012; (2) 3/28/2012-5/21/2014; and (3) 5/22/2014-12/31/2016. Cox-proportional hazards regression modelling was used to compare trends of PC consultation among cohorts. Of 284 patients identified, 184 patients received PC consultation, whereas 15 patients died before receiving a PC consult. Median follow-up time until an event or censor was 257 days (range: 1,900). Patients in the most recent cohort had a shorter median time to first PC consult (57 days) compared to those in the first (374 days) and second (186 days) cohorts. On multivariable analysis, patients in the third cohort were more likely to undergo a PC consultation earlier in their metastatic illness (HR: 1.8, 95% CI: 1.2,2.8). Over a six-year period, palliative care consultation occurred earlier for metastatic patients treated with PRT at our institution. Copyright © 2018. Published by Elsevier Inc.

Earlier time to aerobic exercise is associated with faster recovery following acute sport concussion.

PubMed

Lawrence, David Wyndham; Richards, Doug; Comper, Paul; Hutchison, Michael G

2018-01-01

To determine whether earlier time to initiation of aerobic exercise following acute concussion is associated with time to full return to (1) sport and (2) school or work. A retrospective stratified propensity score survival analysis of acute (≤14 days) concussion was used to determine whether time (days) to initiation of aerobic exercise post-concussion was associated with, both, time (days) to full return to (1) sport and (2) school or work. A total of 253 acute concussions [median (IQR) age, 17.0 (15.0-20.0) years; 148 (58.5%) males] were included in this study. Multivariate Cox regression models identified that earlier time to aerobic exercise was associated with faster return to sport and school/work adjusting for other covariates, including quintile propensity strata. For each successive day in delay to initiation of aerobic exercise, individuals had a less favourable recovery trajectory. Initiating aerobic exercise at 3 and 7 days following injury was associated with a respective 36.5% (HR, 0.63; 95% CI, 0.53-0.76) and 73.2% (HR, 0.27; 95% CI, 0.16-0.45) reduced probability of faster full return to sport compared to within 1 day; and a respective 45.9% (HR, 0.54; 95% CI, 0.44-0.66) and 83.1% (HR, 0.17; 95% CI, 0.10-0.30) reduced probability of faster full return to school/work. Additionally, concussion history, symptom severity, LOC deleteriously influenced concussion recovery. Earlier initiation of aerobic exercise was associated with faster full return to sport and school or work. This study provides greater insight into the benefits and safety of aerobic exercise within the first week of the injury.

Earlier nesting by generalist predatory bird is associated with human responses to climate change.

PubMed

Smith, Shawn H; Steenhof, Karen; McClure, Christopher J W; Heath, Julie A

2017-01-01

Warming temperatures cause temporal changes in growing seasons and prey abundance that drive earlier breeding by birds, especially dietary specialists within homogeneous habitat. Less is known about how generalists respond to climate-associated shifts in growing seasons or prey phenology, which may occur at different rates across land cover types. We studied whether breeding phenology of a generalist predator, the American kestrel (Falco sparverius), was associated with shifts in growing seasons and, presumably, prey abundance, in a mosaic of non-irrigated shrub/grasslands and irrigated crops/pastures. We examined the relationship between remotely-sensed normalized difference vegetation index (NDVI) and abundance of small mammals that, with insects, constitute approximately 93% of kestrel diet biomass. We used NDVI to estimate the start of the growing season (SoGS) in irrigated and non-irrigated lands from 1992 to 2015 and tested whether either estimate of annual SoGS predicted the timing of kestrel nesting. Finally, we examined relationships among irrigated SoGS, weather and crop planting. NDVI was a useful proxy for kestrel prey because it predicted small mammal abundance and past studies showed that NDVI predicts insect abundance. NDVI-estimated SoGS advanced significantly in irrigated lands (β = -1·09 ± 0·30 SE) but not in non-irrigated lands (β = -0·57 ± 0·53). Average date of kestrel nesting advanced 15 days in the past 24 years and was positively associated with the SoGS in irrigated lands, but not the SoGS in non-irrigated lands. Advanced SoGS in irrigated lands was related to earlier planting of crops after relatively warm winters, which were more common in recent years. Despite different patterns of SoGS change between land cover types, kestrel nesting phenology shifted with earlier prey availability in irrigated lands. Kestrels may preferentially track prey in irrigated lands over non-irrigated lands because of higher quality prey on

Rockfall travel distances theoretical distributions

NASA Astrophysics Data System (ADS)

Jaboyedoff, Michel; Derron, Marc-Henri; Pedrazzini, Andrea

2017-04-01

The probability of propagation of rockfalls is a key part of hazard assessment, because it permits to extrapolate the probability of propagation of rockfall either based on partial data or simply theoretically. The propagation can be assumed frictional which permits to describe on average the propagation by a line of kinetic energy which corresponds to the loss of energy along the path. But loss of energy can also be assumed as a multiplicative process or a purely random process. The distributions of the rockfall block stop points can be deduced from such simple models, they lead to Gaussian, Inverse-Gaussian, Log-normal or exponential negative distributions. The theoretical background is presented, and the comparisons of some of these models with existing data indicate that these assumptions are relevant. The results are either based on theoretical considerations or by fitting results. They are potentially very useful for rockfall hazard zoning and risk assessment. This approach will need further investigations.

Recent gestational diabetes was associated with mothers stopping predominant breastfeeding earlier in a multi-ethnic population.

PubMed

Baerug, Anne; Sletner, Line; Laake, Petter; Fretheim, Atle; Løland, Beate Fossum; Waage, Christin W; Birkeland, Kåre I; Jenum, Anne Karen

2018-06-01

It has previously been shown that breastfeeding may reduce the risk of type 2 diabetes in mothers with recent gestational diabetes mellitus (GDM). This study compared the cessation of predominant breastfeeding in mothers with and without recent GDM in a multi-ethnic population. From May 2008 to May 2010, healthy pregnant women attending antenatal care provided by community health services in Eastern Oslo, Norway were recruited. We included 616 women-58% non-Western-and interviewed and examined them at a mean of 15 and 28 weeks of gestation and 14 weeks' postpartum. Cox regression models examined the association between GDM, as assessed by the 2013 World Health Organization criteria, and breastfeeding cessation. Overall, 190 of the 616 (31%) mothers had GDM and they ended predominant breastfeeding earlier than mothers without GDM, with an adjusted hazard ratio (aHR) of 1.33 and 95% confidence interval (95% CI) of 1.01-1.77. Mothers of South Asian origin ended predominant breastfeeding earlier than Western European mothers in the adjusted analysis (aHR 1.53, 95% CI: 1.04-2.25), but Middle Eastern mothers did not. Recent gestational diabetes was associated with earlier cessation of predominant breastfeeding in Western European and non-Western women. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Tidal Wave II Revisited: A Review of Earlier Enrollment Projections for California Higher Education.

ERIC Educational Resources Information Center

Hayward, Gerald C.; Breneman, David W.; Estrada, Leobardo F.

This report examined enrollment projections for higher education institutions in California in relation to earlier projections conducted in the mid-1990s that forecasted steep declines in enrollment. It notes that California's remarkable economic recovery over the last several years has allowed it to fund higher education enrollment growth at a…

Variations in a university subject pool as a function of earlier or later participation and self-report: a replication and extension.

PubMed

Bernard, Larry C; Walsh, R Patricia

2002-10-01

The present study replicated and extended earlier research on temporal sampling effects in university subject pools. Data were obtained from 236 participants, 79 men and 157 women, in a university subject pool during a 15-wk. semester. Without knowing the purpose of the study, participants self-selected to participate earlier (Weeks 4 and 5; n = 105) or later (Weeks 14 and 15; n = 131). Three hypotheses were investigated: (1) that the personality patterns of earlier and later participants on the NEO Personality Inventory-Revised and the Personality Research Form differ significantly, with earlier participants scoring higher on the latter scales reflecting social responsibility and higher on former Conscientiousness and Neuroticism scales; (2) that there are similar significant differences between participants in the earlier and later groups compared to the male and female college normative samples for the two tests: and (3) that earlier participants will have higher actual Scholastic Assessment Test scores and Grade Point Averages. Also investigated was whether participants' foreknowledge that their actual Scholastic Assessment Test scores and Grade Point Averages would be obtained would affect their accuracy of self-report. In contrast to prior research, neither the first nor second hypothesis was supported by the current study; there do not appear to be consistent differences on personality variables. However, the third hypothesis was supported. Earlier participants had higher actual high school Grade Point Average, college Grade Point Average, and Scholastic Assessment Test Verbal scores. Foreknowledge that actual Scholastic Assessment Test scores and Grade Point Averages would be obtained did not affect the accuracy of self-report. In addition, later participants significantly over-reported their scores, and significantly more women than men and more first-year than senior-year subjects participated in the early group.

Higher Childhood Red Meat Intake Frequency Is Associated with Earlier Age at Menarche.

PubMed

Jansen, Erica C; Marín, Constanza; Mora-Plazas, Mercedes; Villamor, Eduardo

2016-03-09

Early age at menarche is associated with increased breast cancer risk. Red meat consumption in adolescence predicts breast cancer risk, but it is unknown whether it is also related to earlier menarche. We studied the association between intake of red meat at ages 5-12 y and age at menarche in a prospective study. We assessed usual diets with a food-frequency questionnaire in a group of 456 girls aged 8.4 ± 1.7 y and followed them for a median 5.6 y in Bogotá, Colombia. Girls were asked periodically about the occurrence and date of menarche. Median age at menarche was estimated with use of Kaplan-Meier survival probabilities by categories of red meat intake frequency. Cox proportional hazards models were used to compare the incidence of menarche by red meat intake frequency, adjusting for potential sociodemographic and dietary confounders including total energy intake and intake frequency of other animal food groups (dairy, poultry, freshwater fish, tuna/sardines, eggs, and innards). Median age at menarche was 12.4 y. After adjustment for total energy intake, maternal parity, and socioeconomic status, red meat intake frequency was inversely associated with age at menarche. When compared with girls with red meat intake <4 times/wk, those consuming it ≥2 times/d had a significantly earlier age at menarche (HR: 1.64; 95% CI: 1.11, 2.41; P-trend = 0.0009). Incidentally, we found that girls with tuna/sardine intake >1 time/wk had a significantly later age at menarche (HR: 0.62; 95% CI: 0.42, 0.90; P = 0.01) than those with intake <1 time/mo. Intake frequency of other animal food groups was not significantly associated with age at menarche. Higher red meat intake frequency during childhood is associated with an earlier age at menarche, whereas greater fatty fish intake frequency is associated with a later menarcheal age. © 2016 American Society for Nutrition.

On the complex relationship between energy expenditure and longevity: Reconciling the contradictory empirical results with a simple theoretical model.

PubMed

Hou, Chen; Amunugama, Kaushalya

2015-07-01

The relationship between energy expenditure and longevity has been a central theme in aging studies. Empirical studies have yielded controversial results, which cannot be reconciled by existing theories. In this paper, we present a simple theoretical model based on first principles of energy conservation and allometric scaling laws. The model takes into considerations the energy tradeoffs between life history traits and the efficiency of the energy utilization, and offers quantitative and qualitative explanations for a set of seemingly contradictory empirical results. We show that oxidative metabolism can affect cellular damage and longevity in different ways in animals with different life histories and under different experimental conditions. Qualitative data and the linearity between energy expenditure, cellular damage, and lifespan assumed in previous studies are not sufficient to understand the complexity of the relationships. Our model provides a theoretical framework for quantitative analyses and predictions. The model is supported by a variety of empirical studies, including studies on the cellular damage profile during ontogeny; the intra- and inter-specific correlations between body mass, metabolic rate, and lifespan; and the effects on lifespan of (1) diet restriction and genetic modification of growth hormone, (2) the cold and exercise stresses, and (3) manipulations of antioxidant. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Clinical presentation of retinoblastoma in Alexandria: A step toward earlier diagnosis.

PubMed

Soliman, Sameh E; Eldomiaty, Wesam; Goweida, Mohamed B; Dowidar, Amgad

2017-01-01

To evaluate the clinical presentation of retinoblastoma in Alexandria, Egypt, correlate the timing of accurate diagnosis with the presence of advanced disease and identify causes of delayed presentation. Retrospective noncomparative single institution study reviews demographic and clinical data of all new children with retinoblastoma presenting to Alexandria Main University ocular oncology clinic (OOC) from January 2012 to June 2014. Diagnosis time was from initial parental complaint to retinoblastoma diagnosis and referral time was from retinoblastoma diagnosis to presentation to the Alexandria OCC. Delayed Diagnosis and referral were counted if >2 weeks. Advanced presentation is defined as clinical TNMH (8th edition) staging of cT2 or cT3 (international intraocular retinoblastoma classification group D or E) in at least one eye or the presence of extra-ocular disease (cT4). Seventy eyes of 47 children were eligible: 52% unilateral, 7% with family history and 96% presented with leukocorea. Sixty-four percent of children had advanced intraocular disease and none had extra-ocular disease. Delayed presentation occurred in 58% of children and was significantly associated with advanced disease in both unilaterally and bilaterally affected children (p = 0.003, 0.002 respectively). The delay in diagnosis was more in unilateral cases while the delay in referral was more in bilateral cases. The main cause of delayed presentation in unilateral retinoblastoma was misdiagnosis (30%) while parental shopping for second medical opinion (30%) was the main cause in bilateral children. Delayed diagnosis is a problem affecting retinoblastoma management. Better medical education and training, health education and earlier screening are recommended to achieve earlier diagnosis.

Cholesterol testing and results

MedlinePlus

... profile results; Hyperlipidemia-results; Lipid disorder test results; Heart disease - cholesterol results ... at an earlier age if you have: Diabetes Heart disease Stroke High blood pressure A strong family history ...

The decision to conduct a head-to-head comparative trial: a game-theoretic analysis.

PubMed

Mansley, Edward C; Elbasha, Elamin H; Teutsch, Steven M; Berger, Marc L

2007-01-01

Recent Medicare legislation calls on the Agency for Healthcare Research and Quality to conduct research related to the comparative effectiveness of health care items and services, including prescription drugs. This reinforces earlier calls for head-to-head comparative trials of clinically relevant treatment alternatives. Using a game-theoretic model, the authors explore the decision of pharmaceutical companies to conduct such trials. The model suggests that an important factor affecting this decision is the potential loss in market share and profits following a result of inferiority or comparability. This hidden cost is higher for the market leader than the market follower, making it less likely that the leader will choose to conduct a trial. The model also suggests that in a full-information environment, it will never be the case that both firms choose to conduct such a trial. Furthermore, if market shares and the probability of proving superiority are similar for both firms, it is quite possible that neither firm will choose to conduct a trial. Finally, the results indicate that incentives that offset the direct cost of a trial can prevent a no-trial equilibrium, even when both firms face the possibility of an inferior outcome.

Design a Fuzzy Rule-based Expert System to Aid Earlier Diagnosis of Gastric Cancer.

PubMed

Safdari, Reza; Arpanahi, Hadi Kazemi; Langarizadeh, Mostafa; Ghazisaiedi, Marjan; Dargahi, Hossein; Zendehdel, Kazem

2018-01-01

Screening and health check-up programs are most important sanitary priorities, that should be undertaken to control dangerous diseases such as gastric cancer that affected by different factors. More than 50% of gastric cancer diagnoses are made during the advanced stage. Currently, there is no systematic approach for early diagnosis of gastric cancer. to develop a fuzzy expert system that can identify gastric cancer risk levels in individuals. This system was implemented in MATLAB software, Mamdani inference technique applied to simulate reasoning of experts in the field, a total of 67 fuzzy rules extracted as a rule-base based on medical expert's opinion. 50 case scenarios were used to evaluate the system, the information of case reports is given to the system to find risk level of each case report then obtained results were compared with expert's diagnosis. Results revealed that sensitivity was 92.1% and the specificity was 83.1%. The results show that is possible to develop a system that can identify High risk individuals for gastric cancer. The system can lead to earlier diagnosis, this may facilitate early treatment and reduce gastric cancer mortality rate.

Quantifying the Economic Value and Quality of Life Impact of Earlier Influenza Vaccination

PubMed Central

Lee, Bruce Y.; Bartsch, Sarah M.; Brown, Shawn T.; Cooley, Philip; Wheaton, William D.; Zimmerman, Richard K.

2015-01-01

Background Influenza vaccination is administered throughout the influenza disease season, even as late as March. Given such timing, what is the value of vaccinating the population earlier than currently being practiced? Methods We used real data on when individuals were vaccinated in Allegheny County, Pennsylvania, and the following 2 models to determine the value of vaccinating individuals earlier (by the end of September, October, and November): Framework for Reconstructing Epidemiological Dynamics (FRED), an agent-based model (ABM), and FluEcon, our influenza economic model that translates cases from the ABM to outcomes and costs [health care and lost productivity costs and quality-adjusted life-years (QALYs)]. We varied the reproductive number (R0) from 1.2 to 1.6. Results Applying the current timing of vaccinations averted 223,761 influenza cases, $16.3 million in direct health care costs, $50.0 million in productivity losses, and 804 in QALYs, compared with no vaccination (February peak, R0 1.2). When the population does not have preexisting immunity and the influenza season peaks in February (R0 1.2–1.6), moving individuals who currently received the vaccine after September to the end of September could avert an additional 9634–17,794 influenza cases, $0.6–$1.4 million in direct costs, $2.1–$4.0 million in productivity losses, and 35–64 QALYs. Moving the vaccination of just children to September (R0 1.2–1.6) averted 11,366–1660 influenza cases, $0.6–$0.03 million in direct costs, $2.3–$0.2 million in productivity losses, and 42–8 QALYs. Moving the season peak to December increased these benefits, whereas increasing preexisting immunity reduced these benefits. Conclusion Even though many people are vaccinated well after September/October, they likely are still vaccinated early enough to provide substantial cost-savings. PMID:25590676

Changing facial phenotype in Cohen syndrome: towards clues for an earlier diagnosis.

PubMed

El Chehadeh-Djebbar, Salima; Blair, Edward; Holder-Espinasse, Muriel; Moncla, Anne; Frances, Anne-Marie; Rio, Marlène; Debray, François-Guillaume; Rump, Patrick; Masurel-Paulet, Alice; Gigot, Nadège; Callier, Patrick; Duplomb, Laurence; Aral, Bernard; Huet, Frédéric; Thauvin-Robinet, Christel; Faivre, Laurence

2013-07-01

Cohen syndrome (CS) is a rare autosomal recessive condition caused by mutations and/or large rearrangements in the VPS13B gene. CS clinical features, including developmental delay, the typical facial gestalt, chorioretinal dystrophy (CRD) and neutropenia, are well described. CS diagnosis is generally raised after school age, when visual disturbances lead to CRD diagnosis and to VPS13B gene testing. This relatively late diagnosis precludes accurate genetic counselling. The aim of this study was to analyse the evolution of CS facial features in the early period of life, particularly before school age (6 years), to find clues for an earlier diagnosis. Photographs of 17 patients with molecularly confirmed CS were analysed, from birth to preschool age. By comparing their facial phenotype when growing, we show that there are no special facial characteristics before 1 year. However, between 2 and 6 years, CS children already share common facial features such as a short neck, a square face with micrognathia and full cheeks, a hypotonic facial appearance, epicanthic folds, long ears with an everted upper part of the auricle and/or a prominent lobe, a relatively short philtrum, a small and open mouth with downturned corners, a thick lower lip and abnormal eye shapes. These early transient facial features evolve to typical CS facial features with aging. These observations emphasize the importance of ophthalmological tests and neutrophil count in children in preschool age presenting with developmental delay, hypotonia and the facial features we described here, for an earlier CS diagnosis.

Inevitable end-of-21st-century trends toward earlier surface runoff timing in California's Sierra Nevada Mountains

NASA Astrophysics Data System (ADS)

Schwartz, M. A.; Hall, A. D.; Sun, F.; Walton, D.; Berg, N.

2015-12-01

Hybrid dynamical-statistical downscaling is used to produce surface runoff timing projections for California's Sierra Nevada, a high-elevation mountain range with significant seasonal snow cover. First, future climate change projections (RCP8.5 forcing scenario, 2081-2100 period) from five CMIP5 global climate models (GCMs) are dynamically downscaled. These projections reveal that future warming leads to a shift toward earlier snowmelt and surface runoff timing throughout the Sierra Nevada region. Relationships between warming and surface runoff timing from the dynamical simulations are used to build a simple statistical model that mimics the dynamical model's projected surface runoff timing changes given GCM input or other statistically-downscaled input. This statistical model can be used to produce surface runoff timing projections for other GCMs, periods, and forcing scenarios to quantify ensemble-mean changes, uncertainty due to intermodel variability and consequences stemming from choice of forcing scenario. For all CMIP5 GCMs and forcing scenarios, significant trends toward earlier surface runoff timing occur at elevations below 2500m. Thus, we conclude that trends toward earlier surface runoff timing by the end-of-the-21st century are inevitable. The changes to surface runoff timing diagnosed in this study have implications for many dimensions of climate change, including impacts on surface hydrology, water resources, and ecosystems.

Advanced turboprop noise prediction: Development of a code at NASA Langley based on recent theoretical results

NASA Technical Reports Server (NTRS)

Farassat, F.; Dunn, M. H.; Padula, S. L.

1986-01-01

The development of a high speed propeller noise prediction code at Langley Research Center is described. The code utilizes two recent acoustic formulations in the time domain for subsonic and supersonic sources. The structure and capabilities of the code are discussed. Grid size study for accuracy and speed of execution on a computer is also presented. The code is tested against an earlier Langley code. Considerable increase in accuracy and speed of execution are observed. Some examples of noise prediction of a high speed propeller for which acoustic test data are available are given. A brisk derivation of formulations used is given in an appendix.

Benchmark results and theoretical treatments for valence-to-core x-ray emission spectroscopy in transition metal compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mortensen, D. R.; Seidler, G. T.; Kas, Joshua J.

We report measurement of the valence-to-core (VTC) region of the K-shell x-ray emission spectra from several Zn and Fe inorganic compounds, and their critical comparison with several existing theoretical treatments. We find generally good agreement between the respective theories and experiment, and in particular find an important admixture of dipole and quadrupole character for Zn materials that is much weaker in Fe-based systems. These results on materials whose simple crystal structures should not, a prior, pose deep challenges to theory, will prove useful in guiding the further development of DFT and time-dependent DFT methods for VTC-XES predictions and their comparisonmore » to experiment.« less

A comparison of experimental and theoretical results for leakage, pressure distribution, and rotordynamic coefficients for annular gas seals

NASA Technical Reports Server (NTRS)

Nicks, C. O.; Childs, D. W.

1984-01-01

The importance of seal behavior in rotordynamics is discussed and current annular seal theory is reviewed. A Nelson's analytical-computational method for determining rotordynamic coefficients for this type of compressible-flow seal is outlined. Various means for the experimental identification of the dynamic coefficients are given, and the method employed at the Texas A and M University (TAMU) test facility is explained. The TAMU test apparatus is described, and the test procedures are discussed. Experimental results, including leakage, entrance-loss coefficients, pressure distributions, and rotordynamic coefficients for a smooth and a honeycomb constant-clearance seal are presented and compared to theoretical results from Nelson's analysis. The results for both seals show little sensitivity to the running speed over the test range. Agreement between test results and theory for leakage through the seal is satisfactory. Test results for direct stiffness show a greater sensitivity to fluid pre-rotation than predicted. Results also indicate that the deliberately roughened surface of the honeycomb seal provides improved stability versus the smooth seal.

On the Correct Analysis of the Foundations of Theoretical Physics

NASA Astrophysics Data System (ADS)

Kalanov, Temur Z.

2007-04-01

The problem of truth in science -- the most urgent problem of our time -- is discussed. The correct theoretical analysis of the foundations of theoretical physics is proposed. The principle of the unity of formal logic and rational dialectics is a methodological basis of the analysis. The main result is as follows: the generally accepted foundations of theoretical physics (i.e. Newtonian mechanics, Maxwell electrodynamics, thermodynamics, statistical physics and physical kinetics, the theory of relativity, quantum mechanics) contain the set of logical errors. These errors are explained by existence of the global cause: the errors are a collateral and inevitable result of the inductive way of cognition of the Nature, i.e. result of movement from formation of separate concepts to formation of the system of concepts. Consequently, theoretical physics enters the greatest crisis. It means that physics as a science of phenomenon leaves the progress stage for a science of essence (information). Acknowledgment: The books ``Surprises in Theoretical Physics'' (1979) and ``More Surprises in Theoretical Physics'' (1991) by Sir Rudolf Peierls stimulated my 25-year work.

Effects of earlier sea ice breakup on survival and population size of polar bears in western Hudson Bay

USGS Publications Warehouse

Regehr, E.V.; Lunn, N.J.; Amstrup, Steven C.; Stirling, I.

2007-01-01

Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult to quantify. We used a flexible extension of Cormack-Jolly-Seber capture-recapture models to estimate population size and survival for polar bears (Ursus maritimus), one of the most ice-dependent of Arctic marine mammals. We analyzed data for polar bears captured from 1984 to 2004 along the western coast of Hudson Bay and in the community of Churchill, Manitoba, Canada. The Western Hudson Bay polar bear population declined from 1,194 (95% CI = 1,020-1,368) in 1987 to 935 (95% CI = 794-1,076) in 2004. Total apparent survival of prime-adult polar bears (5-19 yr) was stable for females (0.93; 95% CI = 0.91-0.94) and males (0.90; 95% CI = 0.88-0.91). Survival of juvenile, subadult, and senescent-adult polar bears was correlated with spring sea ice breakup date, which was variable among years and occurred approximately 3 weeks earlier in 2004 than in 1984. We propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching on human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the species' range, our findings may foreshadow the demographic responses and management challenges that more northerly polar bear populations will experience if climatic warming in the Arctic continues as

5 CFR Appendix A to Subpart C of... - Present Value Conversion Factors for Earlier Commencing Date of Annuities of Current and Former...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Present Value Conversion Factors for Earlier Commencing Date of Annuities of Current and Former Spouses of Deceased Separated Employees A...—Present Value Conversion Factors for Earlier Commencing Date of Annuities of Current and Former Spouses of...

Organized screening detects breast cancer at earlier stage regardless of molecular phenotype.

PubMed

Holloway, Claire M B; Jiang, Li; Whitehead, Marlo; Racz, Jennifer M; Groome, Patti A

2018-06-16

Mortality reduction attributable to organized breast screening is modest. Screening may be less effective at detecting more aggressive cancers at an earlier stage. This study was conducted to determine the relative efficacy of screening mammography to detect cancers at an earlier stage by molecular phenotype. We identified 2882 women with primary invasive breast cancer diagnosed between January 1, 2008 and December 31, 2012 and who had a mammogram through the Ontario Breast Screening Program in the 28 months before diagnosis. Five tumor phenotypes were defined by expression of estrogen (ER) and progesterone (PR) receptors and HER2/neu oncogene. We conducted univariable and multivariable analyses to describe the predictors of detection as an interval cancer. Additional analyses identified predictors of detection at stages II, III, or IV compared with stage I, by phenotype. Analyses were adjusted for the effects of age, grade, and breast density. ER negative and HER2 positive tumors were over-represented among interval cancers, and triple negative cancers were more likely than ER +/HER2 - cancers to be detected as interval cancers OR 2.5 (95% CI 2.0-3.2, p < 0.0001). Method of detection (interval vs. screen) and molecular phenotype were independently associated with stage at diagnosis (p < 0.0001), but there was no interaction between method of detection and phenotype (p = 0.44). In a screened population, triple negative and HER2 + breast cancers are diagnosed at a higher stage but this appears to be due to higher growth rates of these tumors rather than a relative inability of screening to detect them.

A primary care Web-based Intervention Modeling Experiment replicated behavior changes seen in earlier paper-based experiment.

PubMed

Treweek, Shaun; Francis, Jill J; Bonetti, Debbie; Barnett, Karen; Eccles, Martin P; Hudson, Jemma; Jones, Claire; Pitts, Nigel B; Ricketts, Ian W; Sullivan, Frank; Weal, Mark; MacLennan, Graeme

2016-12-01

Intervention Modeling Experiments (IMEs) are a way of developing and testing behavior change interventions before a trial. We aimed to test this methodology in a Web-based IME that replicated the trial component of an earlier, paper-based IME. Three-arm, Web-based randomized evaluation of two interventions (persuasive communication and action plan) and a "no intervention" comparator. The interventions were designed to reduce the number of antibiotic prescriptions in the management of uncomplicated upper respiratory tract infection. General practitioners (GPs) were invited to complete an online questionnaire and eight clinical scenarios where an antibiotic might be considered. One hundred twenty-nine GPs completed the questionnaire. GPs receiving the persuasive communication did not prescribe an antibiotic in 0.70 more scenarios (95% confidence interval [CI] = 0.17-1.24) than those in the control arm. For the action plan, GPs did not prescribe an antibiotic in 0.63 (95% CI = 0.11-1.15) more scenarios than those in the control arm. Unlike the earlier IME, behavioral intention was unaffected by the interventions; this may be due to a smaller sample size than intended. A Web-based IME largely replicated the findings of an earlier paper-based study, providing some grounds for confidence in the IME methodology. Copyright © 2016 Elsevier Inc. All rights reserved.

Retrospective study of reasons for improved survival in patients with breast cancer in east Anglia: earlier diagnosis or better treatment.

PubMed Central

Stockton, D.; Davies, T.; Day, N.; McCann, J.

1997-01-01

OBJECTIVES: To investigate the recent fall in mortality from breast cancer in England and Wales, and to determine the relative contributions of improvements in treatment and earlier detection of tumours. DESIGN: Retrospective study of all women with breast cancer registered by the East Anglian cancer registry and diagnosed between 1982 and 1989. SUBJECTS: 3965 patients diagnosed 1982-5 compared with 4665 patients diagnosed 1986-9, in three age groups 0-49, 50-64, > or = 65 years, with information on stage at diagnosis and survival. MAIN OUTCOME MEASURES: Three year relative survival rates by time period, age group, and stage; relative hazard ratios for each time period and age group derived from Cox's proportional hazards model, adjusted for single year of age and stage. RESULTS: Survival improved in the later time period, although there was little stage specific improvement. The proportion of early stage tumours increased especially in the 50-64 year age group, and adjustment for stage accounted for over half of the improvement in survival in women aged under 65 years. CONCLUSION: Over half of the drop in mortality in women aged under 65 years seems to be attributable to earlier detection of tumours, which has been observed since the mid-1980s. This could have resulted from an increase in breast awareness predating the start of the breast screening programme. PMID:9056796

Hemodynamic parameters change earlier than tissue oxygen tension in hemorrhage.

PubMed

Pestel, Gunther J; Fukui, Kimiko; Kimberger, Oliver; Hager, Helmut; Kurz, Andrea; Hiltebrand, Luzius B

2010-05-15

Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after preparation, baseline measurements were taken. At first, 5% of total blood volume was withdrawn, followed by another 5% increment, and then in 10% increments until death. After withdrawal of 5% of estimated blood volume, dPP increased from 6.1% +/- 3.0% to 20.8% +/- 2.7% (P < 0.01). Mean arterial pressure (MAP), mean pulmonary artery pressure (PAP) and pulmonary artery occlusion pressure (PAOP) decreased with a blood loss of 10% (P < 0.01). Cardiac output (CO) changed after a blood loss of 20% (P < 0.05). Tissue oxygen tension in central organs, and blood flow in the jejunal muscularis decreased (P < 0.05) after a blood loss of 20%. Tissue oxygen tension in the skin, and jejunal mucosa blood flow decreased (P < 0.05) after a blood loss of 40% and 50%, respectively. In this hemorrhagic pig model systemic hemodynamic parameters were more sensitive to detect acute hypovolemia than tissue oxygen tension measurements or jejunal LDF measurements. Acute blood loss was detected first by dPP. Copyright (c) 2010 Elsevier Inc. All rights reserved.

A comparison of experimental and theoretical results for leakage, pressure gradients, and rotordynamic coefficients for tapered annular gas seal

NASA Technical Reports Server (NTRS)

Elrod, D. A.; Childs, D. W.

1986-01-01

A brief review of current annular seal theory and a discussion of the predicted effect on stiffness of tapering the seal stator are presented. An outline of Nelson's analytical-computational method for determining rotordynamic coefficients for annular compressible-flow seals is included. Modifications to increase the maximum rotor speed of an existing air-seal test apparatus at Texas A&M University are described. Experimental results, including leakage, entrance-loss coefficients, pressure distributions, and normalized rotordynamic coefficients, are presented for four convergent-tapered, smooth-rotor, smooth-stator seals. A comparison of the test results shows that an inlet-to-exit clearance ratio of 1.5 to 2.0 provides the maximum direct stiffness, a clearance ratio of 2.5 provides the greatest stability, and a clearance ratio of 1.0 provides the least stability. The experimental results are compared to theoretical results from Nelson's analysis with good agreement. Test results for cross-coupled stiffness show less sensitivity of fluid prerotation than predicted.

Missed opportunities for earlier diagnosis of HIV in patients who presented with advanced HIV disease: a retrospective cohort study

PubMed Central

Levy, Itzchak; Maor, Yasmin; Mahroum, Naim; Olmer, Liraz; Wieder, Anat; Litchevski, Vladislav; Mor, Orna; Rahav, Galia

2016-01-01

Objective To quantify and characterise missed opportunities for earlier HIV diagnosis in patients diagnosed with advanced HIV. Design A retrospective observational cohort study. Setting A central tertiary medical centre in Israel. Measures The proportion of patients with advanced HIV, the proportion of missed opportunities to diagnose them earlier, and the rate of clinical indicator diseases (CIDs) in those patients. Results Between 2010 and 2015, 356 patients were diagnosed with HIV, 118 (33.4%) were diagnosed late, 57 (16%) with advanced HIV disease. Old age (OR=1.45 (95% CI 1.16 to 1.74)) and being heterosexual (OR=2.65 (95% CI 1.21 to 5.78)) were significant risk factors for being diagnosed late. All patients with advanced disease had at least one CID that did not lead to an HIV test in the 5 years prior to AIDS diagnosis. The median time between CID and AIDS diagnosis was 24 months (IQR 10–30). 60% of CIDs were missed by a general practitioner and 40% by a specialist. Conclusions Missed opportunities to early diagnosis of HIV occur in primary and secondary care. Lack of national guidelines, lack of knowledge regarding CIDs and communication barriers with patients may contribute to a late diagnosis of HIV. PMID:28186940

37 CFR 1.78 - Claiming benefit of earlier filing date and cross-references to other applications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Claiming benefit of earlier filing date and cross-references to other applications. 1.78 Section 1.78 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN...

37 CFR 1.78 - Claiming benefit of earlier filing date and cross-references to other applications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Claiming benefit of earlier filing date and cross-references to other applications. 1.78 Section 1.78 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE GENERAL RULES OF PRACTICE IN...

Electronic orbital response of regular extended and infinite periodic systems to magnetic fields. I. Theoretical foundations for static case

NASA Astrophysics Data System (ADS)

Springborg, Michael; Molayem, Mohammad; Kirtman, Bernard

2017-09-01

A theoretical treatment for the orbital response of an infinite, periodic system to a static, homogeneous, magnetic field is presented. It is assumed that the system of interest has an energy gap separating occupied and unoccupied orbitals and a zero Chern number. In contrast to earlier studies, we do not utilize a perturbation expansion, although we do assume the field is sufficiently weak that the occurrence of Landau levels can be ignored. The theory is developed by analyzing results for large, finite systems and also by comparing with the analogous treatment of an electrostatic field. The resulting many-electron Hamilton operator is forced to be hermitian, but hermiticity is not preserved, in general, for the subsequently derived single-particle operators that determine the electronic orbitals. However, we demonstrate that when focusing on the canonical solutions to the single-particle equations, hermiticity is preserved. The issue of gauge-origin dependence of approximate solutions is addressed. Our approach is compared with several previously proposed treatments, whereby limitations in some of the latter are identified.

DYANA campaign results on long-period atmospheric waves over Thumba and Balasore

NASA Astrophysics Data System (ADS)

Reddi, C. Raghava; Rajeev, K.; Nair, S. Muraleedharan; Subbaraya, B. H.; Rama, G. V.; Appu, K. S.; Narayanan, V.; Apparao, B. V.; Chakravarty, S. C.; Nagpal, O. P.; Perov, S. P.; Kokin, G. A.

1994-12-01

The variation with altitude of the spectral amplitudes of the long period waves in the middle atmospheric zonal and meridional wind over Thumba (8.5°N, 76.9°E) and Balasore (21.5°N, 86.9°E) have shown clearly the enhanced dissipation of the atmospheric waves in the lower stratosphere and near the stratopause. The amplitudes are, in general, large for the lower frequency ( <0.1 cycles/day) waves in the troposphere. While propagating through the tropopause into the stratosphere and above, waves with periods in the range of 5-10 days suffer less attenuation. The dissipation of the atmospheric waves is found to be relatively large for frequencies below 0.1 cycles/day. The results are compared with earlier observational studies and theoretical computations on the propagation of equatorial waves through the middle atmosphere.

Do BRCA1/2 mutation carriers have an earlier onset of natural menopause?

PubMed

van Tilborg, Theodora C; Broekmans, Frank J; Pijpe, Anouk; Schrijver, Lieske H; Mooij, Thea M; Oosterwijk, Jan C; Verhoef, Senno; Gómez Garcia, Encarna B; van Zelst-Stams, Wendy A; Adank, Muriel A; van Asperen, Christi J; van Doorn, Helena C; van Os, Theo A; Bos, Anna M; Rookus, Matti A; Ausems, Margreet G

2016-08-01

It has been hypothesized that BRCA1/2 mutation carriers have an earlier age at natural menopause (ANM), although to date findings are inconclusive. This study assessed the influence of BRCA mutation status on ANM, and aimed to explore the reasons of inconsistency in the literature. Cross-sectional assessment from an ongoing nationwide cohort study among members of BRCA1/2 mutated families. Information was obtained by a standardized questionnaire. Kaplan-Meier curves were constructed, and Cox regression was used to assess the association between BRCA1/2 mutation status and ANM. Adjustments were made for birth cohort, family, smoking, use of hormonal contraceptives, and parity. A total of 1,208 BRCA1/2 mutation carriers and 2,211 proven noncarriers were included. Overall, no association was found between BRCA1/2 mutation status and ANM (adjusted hazard ratio [HR] = 1.06 [95% CI, 0.87-1.30]). We examined if the null finding was due to informative censoring by uptake of risk-reducing salpingo-oophorectomy. Indeed, within the oldest birth cohort, in which the percentage of surgical menopause events was lowest and comparable between carriers and noncarriers, the HR for earlier natural menopause in carriers was 1.45 (95% CI, 1.09-1.94). The second oldest birth cohort, however, demonstrated a decreased HR (0.67 [95% CI, 0.46-0.98]), and thus no trend over birth cohorts was found. Various types of selection bias hamper the comparison of ANM between BRCA1/2 mutation carriers and noncarriers, genetically tested in the clinic.

Main rotor free wake geometry effects on blade air loads and response for helicopters in steady maneuvers. Volume 1: Theoretical formulation and analysis of results

NASA Technical Reports Server (NTRS)

Sadler, S. G.

1972-01-01

A mathematical model and computer program were implemented to study the main rotor free wake geometry effects on helicopter rotor blade air loads and response in steady maneuvers. The theoretical formulation and analysis of results are presented.

Theoretical geology

NASA Astrophysics Data System (ADS)

Mikeš, Daniel

2010-05-01

Theoretical geology Present day geology is mostly empirical of nature. I claim that geology is by nature complex and that the empirical approach is bound to fail. Let's consider the input to be the set of ambient conditions and the output to be the sedimentary rock record. I claim that the output can only be deduced from the input if the relation from input to output be known. The fundamental question is therefore the following: Can one predict the output from the input or can one predict the behaviour of a sedimentary system? If one can, than the empirical/deductive method has changes, if one can't than that method is bound to fail. The fundamental problem to solve is therefore the following: How to predict the behaviour of a sedimentary system? It is interesting to observe that this question is never asked and many a study is conducted by the empirical/deductive method; it seems that the empirical method has been accepted as being appropriate without question. It is, however, easy to argument that a sedimentary system is by nature complex and that several input parameters vary at the same time and that they can create similar output in the rock record. It follows trivially from these first principles that in such a case the deductive solution cannot be unique. At the same time several geological methods depart precisely from the assumption, that one particular variable is the dictator/driver and that the others are constant, even though the data do not support such an assumption. The method of "sequence stratigraphy" is a typical example of such a dogma. It can be easily argued that all the interpretation resulting from a method that is built on uncertain or wrong assumptions is erroneous. Still, this method has survived for many years, nonwithstanding all the critics it has received. This is just one example of the present day geological world and is not unique. Even the alternative methods criticising sequence stratigraphy actually depart from the same

The case for earlier cochlear implantation in postlingually deaf adults.

PubMed

Dowell, Richard C

2016-01-01

This paper aimed to estimate the difference in speech perception outcomes that may occur due to timing of cochlear implantation in relation to the progression of hearing loss. Data from a large population-based sample of adults with acquired hearing loss using cochlear implants (CIs) was used to estimate the effects of duration of hearing loss, age, and pre-implant auditory skills on outcomes for a hypothetical standard patient. A total of 310 adults with acquired severe/profound bilateral hearing loss who received a CI in Melbourne, Australia between 1994 and 2006 provided the speech perception data and demographic information to derive regression equations for estimating CI outcomes. For a hypothetical CI candidate with progressive sensorineural hearing loss, the estimates of speech perception scores following cochlear implantation are significantly better if implantation occurs relatively soon after onset of severe hearing loss and before the loss of all functional auditory skills. Improved CI outcomes and quality of life benefit may be achieved for adults with progressive severe hearing loss if they are implanted earlier in the progression of the pathology.

Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology.

PubMed

Manning, Sturt W; Griggs, Carol B; Lorentzen, Brita; Barjamovic, Gojko; Ramsey, Christopher Bronk; Kromer, Bernd; Wild, Eva Maria

2016-01-01

500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681-1673 BCE (68.2% highest posterior density range), ~20

Integrated Tree-Ring-Radiocarbon High-Resolution Timeframe to Resolve Earlier Second Millennium BCE Mesopotamian Chronology

PubMed Central

Griggs, Carol B.; Lorentzen, Brita; Barjamovic, Gojko; Ramsey, Christopher Bronk; Kromer, Bernd; Wild, Eva Maria

2016-01-01

500 years of ancient Near Eastern history from the earlier second millennium BCE, including such pivotal figures as Hammurabi of Babylon, Šamši-Adad I (who conquered Aššur) and Zimrilim of Mari, has long floated in calendar time subject to rival chronological schemes up to 150+ years apart. Texts preserved on clay tablets provide much information, including some astronomical references, but despite 100+ years of scholarly effort, chronological resolution has proved impossible. Documents linked with specific Assyrian officials and rulers have been found and associated with archaeological wood samples at Kültepe and Acemhöyük in Turkey, and offer the potential to resolve this long-running problem. Here we show that previous work using tree-ring dating to place these timbers in absolute time has fundamental problems with key dendrochronological crossdates due to small sample numbers in overlapping years and insufficient critical assessment. To address, we have integrated secure dendrochronological sequences directly with radiocarbon (14C) measurements to achieve tightly resolved absolute (calendar) chronological associations and identify the secure links of this tree-ring chronology with the archaeological-historical evidence. The revised tree-ring-sequenced 14C time-series for Kültepe and Acemhöyük is compatible only with the so-called Middle Chronology and not with the rival High, Low or New Chronologies. This finding provides a robust resolution to a century of uncertainty in Mesopotamian chronology and scholarship, and a secure basis for construction of a coherent timeframe and history across the Near East and East Mediterranean in the earlier second millennium BCE. Our re-dating also affects an unusual tree-ring growth anomaly in wood from Porsuk, Turkey, previously tentatively associated with the Minoan eruption of the Santorini volcano. This tree-ring growth anomaly is now directly dated ~1681–1673 BCE (68.2% highest posterior density range), ~20

Information theoretic quantification of diagnostic uncertainty.

PubMed

Westover, M Brandon; Eiseman, Nathaniel A; Cash, Sydney S; Bianchi, Matt T

2012-01-01

Diagnostic test interpretation remains a challenge in clinical practice. Most physicians receive training in the use of Bayes' rule, which specifies how the sensitivity and specificity of a test for a given disease combine with the pre-test probability to quantify the change in disease probability incurred by a new test result. However, multiple studies demonstrate physicians' deficiencies in probabilistic reasoning, especially with unexpected test results. Information theory, a branch of probability theory dealing explicitly with the quantification of uncertainty, has been proposed as an alternative framework for diagnostic test interpretation, but is even less familiar to physicians. We have previously addressed one key challenge in the practical application of Bayes theorem: the handling of uncertainty in the critical first step of estimating the pre-test probability of disease. This essay aims to present the essential concepts of information theory to physicians in an accessible manner, and to extend previous work regarding uncertainty in pre-test probability estimation by placing this type of uncertainty within a principled information theoretic framework. We address several obstacles hindering physicians' application of information theoretic concepts to diagnostic test interpretation. These include issues of terminology (mathematical meanings of certain information theoretic terms differ from clinical or common parlance) as well as the underlying mathematical assumptions. Finally, we illustrate how, in information theoretic terms, one can understand the effect on diagnostic uncertainty of considering ranges instead of simple point estimates of pre-test probability.

Selection of children to provide care: the effect of earlier parental transfers.

PubMed

Henretta, J C; Hill, M S; Li, W; Soldo, B J; Wolf, D A

1997-05-01

We use the first wave of data from the Asset and Health Dynamics Among the Oldest Old (AHEAD) study to examine the effects of past parent-to-child financial transfers on selection of a child to provide assistance with basic personal care for unmarried parents. We estimate a fixed-effects conditional logit model and find a positive and significant association between past financial transfers and a child's current helping behavior. The coefficient of past financial transfers is in the direction hypothesized, and its magnitude is 80% as large as that of gender, a well-documented powerful predictor of parental caregiving. There appears to be substantial evidence that earlier parent-to-child financial gifts play a role in determining which child in the family will provide assistance.

A theoretical study of microwave beam absorption by a Rectenna

NASA Technical Reports Server (NTRS)

Ott, J. H.; Rice, J. S.; Thorn, D. C.

1980-01-01

The results of a theoretical study of microwave beam absorption by a rectenna is given. Total absorption of power beam is shown to be theoretically possible. Several improvements in the rectenna design are indicated as a result of analytic modeling. The nature of rectenna scattering and atmospheric effects is discussed.

A theoretical study of microwave beam absorption by a rectenna

NASA Technical Reports Server (NTRS)

Ott, J. H.; Rice, J. S.; Thorn, D. C.

1981-01-01

The results of a theoretical study of microwave beam absorption by a Rectenna are given. Total absorption of the power beam is shown to be theoretically possible. Several improvements in the Rectenna design are indicated as a result of analytic modeling. The nature of Rectenna scattering and atmospheric effects are discussed.

Moderately premature infants at Kaiser Permanente Medical Care Program in California are discharged home earlier than their peers in Massachusetts and the United Kingdom

PubMed Central

Profit, J; Zupancic, J A F; McCormick, M C; Richardson, D K; Escobar, G J; Tucker, J; Tarnow‐Mordi, W; Parry, G

2006-01-01

Objective To compare gestational age at discharge between infants born at 30–34+6 weeks gestational age who were admitted to neonatal intensive care units (NICUs) in California, Massachusetts, and the United Kingdom. Design Prospective observational cohort study. Setting Fifty four United Kingdom, five California, and five Massachusetts NICUs. Subjects A total of 4359 infants who survived to discharge home after admission to an NICU. Main outcome measures Gestational age at discharge home. Results The mean (SD) postmenstrual age at discharge of the infants in California, Massachusetts, and the United Kingdom were 35.9 (1.3), 36.3 (1.3), and 36.3 (1.9) weeks respectively (p  =  0.001). Compared with the United Kingdom, adjusted discharge of infants occurred 3.9 (95% confidence interval (CI) 1.4 to 6.5) days earlier in California, and 0.9 (95% CI −1.2 to 3.0) days earlier in Massachusetts. Conclusions Infants of 30–34+6 weeks gestation at birth admitted and cared for in hospitals in California have a shorter length of stay than those in the United Kingdom. Certain characteristics of the integrated healthcare approach pursued by the health maintenance organisation of the NICUs in California may foster earlier discharge. The California system may provide opportunities for identifying practices for reducing the length of stay of moderately premature infants. PMID:16449257

A theoretical description of the polarization dependence of the sum frequency generation spectroscopy of the water/vapor interface

NASA Astrophysics Data System (ADS)

Perry, Angela; Neipert, Christine; Kasprzyk, Christina Ridley; Green, Tony; Space, Brian; Moore, Preston B.

2005-10-01

An improved time correlation function (TCF) description of sum frequency generation (SFG) spectroscopy was developed and applied to theoretically describing the spectroscopy of the ambient water/vapor interface. A more general TCF expression than was published previously is presented—it is valid over the entire vibrational spectrum for both the real and imaginary parts of the signal. Computationally, earlier time correlation function approaches were limited to short correlation times that made signal processing challenging. Here, this limitation is overcome, and well-averaged spectra are presented for the three independent polarization conditions that are possible for electronically nonresonant SFG. The theoretical spectra compare quite favorably in shape and relative magnitude to extant experimental results in the O H stretching region of water for all polarization geometries. The methodological improvements also allow the calculation of intermolecular SFG spectra. While the intermolecular spectrum of bulk water shows relatively little structure, the interfacial spectra (for polarizations that are sensitive to dipole derivatives normal to the interface—SSP and PPP) show a well-defined intermolecular mode at 875cm-1 that is comparable in intensity to the rest of the intermolecular structure, and has an intensity that is approximately one-sixth of the magnitude of the intense free OH stretching peak. Using instantaneous normal mode methods, the resonance is shown to be due to a wagging mode localized on a single water molecule, almost parallel to the interface, with two hydrogens displaced normal to the interface, and the oxygen anchored in the interface. We have also uncovered the origin of another intermolecular mode at 95cm-1 for the SSP and PPP spectra, and at 220cm-1 for the SPS spectra. These resonances are due to hindered translations perpendicular to the interface for the SSP and PPP spectra, and translations parallel to the interface for the SPS

Recognizing the centrality of gender identity and stereotype knowledge in gender development and moving toward theoretical integration: reply to Bandura and Bussey (2004).

PubMed

Martin, Carol Lynn; Ruble, Diane N; Szkrybalo, Joel

2004-09-01

Most of the critique in the A. Bandura and K. Bussey (see record 2004-18097-001) commentary is a misunderstanding or misrepresentation of the points made by C. L. Martin, D. N. Ruble, and J. Szkrybalo in their 2002 Psychological Bulletin article (see record 2002-18663-003). First, Martin et al. never intended to present a comprehensive theory; instead, it was a review of 2 different cognitive approaches to gender development. Second, there is no time line test that has been failed; instead, gender cognitions may occur earlier than initially believed. Third, Bandura and Bussey dismissed central gender cognitions-gender identity and gender stereotype knowledge-despite considerable evidence in their support. Fourth, Bandura and Bussey never addressed the gaps and ambiguities inherent in their theory that Martin et al. questioned in their earlier article. Finally, Bandura and Bussey's misunderstandings of cognitive theorists' views on socialization agents, sociocultural influences, agency, and motivation created theoretical rifts where none exist. ((c) 2004 APA, all rights reserved)

Hybrid rocket engine, theoretical model and experiment

NASA Astrophysics Data System (ADS)

Chelaru, Teodor-Viorel; Mingireanu, Florin

2011-06-01

The purpose of this paper is to build a theoretical model for the hybrid rocket engine/motor and to validate it using experimental results. The work approaches the main problems of the hybrid motor: the scalability, the stability/controllability of the operating parameters and the increasing of the solid fuel regression rate. At first, we focus on theoretical models for hybrid rocket motor and compare the results with already available experimental data from various research groups. A primary computation model is presented together with results from a numerical algorithm based on a computational model. We present theoretical predictions for several commercial hybrid rocket motors, having different scales and compare them with experimental measurements of those hybrid rocket motors. Next the paper focuses on tribrid rocket motor concept, which by supplementary liquid fuel injection can improve the thrust controllability. A complementary computation model is also presented to estimate regression rate increase of solid fuel doped with oxidizer. Finally, the stability of the hybrid rocket motor is investigated using Liapunov theory. Stability coefficients obtained are dependent on burning parameters while the stability and command matrixes are identified. The paper presents thoroughly the input data of the model, which ensures the reproducibility of the numerical results by independent researchers.

A simple theoretical model for ⁶³Ni betavoltaic battery.

PubMed

Zuo, Guoping; Zhou, Jianliang; Ke, Guotu

2013-12-01

A numerical simulation of the energy deposition distribution in semiconductors is performed for ⁶³Ni beta particles. Results show that the energy deposition distribution exhibits an approximate exponential decay law. A simple theoretical model is developed for ⁶³Ni betavoltaic battery based on the distribution characteristics. The correctness of the model is validated by two literature experiments. Results show that the theoretical short-circuit current agrees well with the experimental results, and the open-circuit voltage deviates from the experimental results in terms of the influence of the PN junction defects and the simplification of the source. The theoretical model can be applied to ⁶³Ni and ¹⁴⁷Pm betavoltaic batteries. Copyright © 2013 Elsevier Ltd. All rights reserved.

Theoretical and experimental studies of reentry plasmas

NASA Technical Reports Server (NTRS)

Dunn, M. G.; Kang, S.

1973-01-01

A viscous shock-layer analysis was developed and used to calculate nonequilibrium-flow species distributions in the plasma layer of the RAM vehicle. The theoretical electron-density results obtained are in good agreement with those measured in flight. A circular-aperture flush-mounted antenna was used to obtain a comparison between theoretical and experimental antenna admittance in the presence of ionized boundary layers of low collision frequency. The electron-temperature and electron-density distributions in the boundary layer were independently measured. The antenna admittance was measured using a four-probe microwave reflectometer and these measured values were found to be in good agreement with those predicted. Measurements were also performed with another type of circular-aperture antenna and good agreement was obtained between the calculations and the experimental results. A theoretical analysis has been completed which permits calculation of the nonequilibrium, viscous shock-layer flow field for a sphere-cone body. Results are presented for two different bodies at several different altitudes illustrating the influences of bluntness and chemical nonequilibrium on several gas dynamic parameters of interest. Plane-wave transmission coefficients were calculated for an approximate space-shuttle body using a typical trajectory.

Earlier adolescent substance use onset predicts stronger connectivity between reward and cognitive control brain networks.

PubMed

Weissman, David G; Schriber, Roberta A; Fassbender, Catherine; Atherton, Olivia; Krafft, Cynthia; Robins, Richard W; Hastings, Paul D; Guyer, Amanda E

2015-12-01

Early adolescent onset of substance use is a robust predictor of future substance use disorders. We examined the relation between age of substance use initiation and resting state functional connectivity (RSFC) of the core reward processing (nucleus accumbens; NAcc) to cognitive control (prefrontal cortex; PFC) brain networks. Adolescents in a longitudinal study of Mexican-origin youth reported their substance use annually from ages 10 to 16 years. At age 16, 69 adolescents participated in a resting state functional magnetic resonance imaging scan. Seed-based correlational analyses were conducted using regions of interest in bilateral NAcc. The earlier that adolescents initiated substance use, the stronger the connectivity between bilateral NAcc and right dorsolateral PFC, right dorsomedial PFC, right pre-supplementary motor area, right inferior parietal lobule, and left medial temporal gyrus. The regions that demonstrated significant positive linear relationships between the number of adolescent years using substances and connectivity with NAcc are nodes in the right frontoparietal network, which is central to cognitive control. The coupling of reward and cognitive control networks may be a mechanism through which earlier onset of substance use is related to brain function over time, a trajectory that may be implicated in subsequent substance use disorders. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Sooner, the Worse? Association between Earlier Age of Sexual Initiation and Worse Adolescent Health and Well-being Outcomes

PubMed Central

Osorio, Alfonso; Lopez-del Burgo, Cristina; Carlos, Silvia; de Irala, Jokin

2017-01-01

This cross-sectional study assesses the association between age of sexual initiation during adolescence and a selection of well-being outcomes regarding that first relationship. High-school adolescents from El Salvador (2,686) and from Peru (3,399) replied to a paper-pencil questionnaire. Those who were sexually initiated replied to several questions regarding their age at sexual initiation, condom use, satisfaction and reasons/circumstances for that sexual relationship. Approximately 19% of participants were sexually initiated (n = 1,179). After retaining participants with valid responses and with sexual initiation ages between 13 and 17, the final sample for this paper consisted of 996 sexually initiated participants (526 Salvadorians and 470 Peruvians). Multiple logistic regression analyses showed that those who initiated sex at earlier ages had worse outcomes compared to those who initiated at older ages. Specifically, they had lower odds of having used a condom, of having good memories of that experience and of having had that first relationship because they were in love. Conversely, they had higher odds of having had that first sexual relationship as a result of peer pressure (“Most of my friends already had sex”), because of partner pressure (“I was afraid to lose him/her,” “My partner told me he/she would leave me” or “I did not know how to say no to a person who insisted”), or as a consequence of different forms of impaired autonomy (“I was under the influence of alcohol or drugs” or “As a consequence of seeing sexual images”). Results show that sex at earlier ages is associated with worse adolescent health and well-being outcomes. PMID:28798715

Combined circulating tumor DNA and protein biomarker-based liquid biopsy for the earlier detection of pancreatic cancers.

PubMed

Cohen, Joshua D; Javed, Ammar A; Thoburn, Christopher; Wong, Fay; Tie, Jeanne; Gibbs, Peter; Schmidt, C Max; Yip-Schneider, Michele T; Allen, Peter J; Schattner, Mark; Brand, Randall E; Singhi, Aatur D; Petersen, Gloria M; Hong, Seung-Mo; Kim, Song Cheol; Falconi, Massimo; Doglioni, Claudio; Weiss, Matthew J; Ahuja, Nita; He, Jin; Makary, Martin A; Maitra, Anirban; Hanash, Samir M; Dal Molin, Marco; Wang, Yuxuan; Li, Lu; Ptak, Janine; Dobbyn, Lisa; Schaefer, Joy; Silliman, Natalie; Popoli, Maria; Goggins, Michael G; Hruban, Ralph H; Wolfgang, Christopher L; Klein, Alison P; Tomasetti, Cristian; Papadopoulos, Nickolas; Kinzler, Kenneth W; Vogelstein, Bert; Lennon, Anne Marie

2017-09-19

The earlier diagnosis of cancer is one of the keys to reducing cancer deaths in the future. Here we describe our efforts to develop a noninvasive blood test for the detection of pancreatic ductal adenocarcinoma. We combined blood tests for KRAS gene mutations with carefully thresholded protein biomarkers to determine whether the combination of these markers was superior to any single marker. The cohort tested included 221 patients with resectable pancreatic ductal adenocarcinomas and 182 control patients without known cancer. KRAS mutations were detected in the plasma of 66 patients (30%), and every mutation found in the plasma was identical to that subsequently found in the patient's primary tumor (100% concordance). The use of KRAS in conjunction with four thresholded protein biomarkers increased the sensitivity to 64%. Only one of the 182 plasma samples from the control cohort was positive for any of the DNA or protein biomarkers (99.5% specificity). This combinatorial approach may prove useful for the earlier detection of many cancer types.

Cost-Effectiveness of Earlier Initiation of Antiretroviral Therapy for Uninsured HIV-Infected Adults

PubMed Central

Schackman, Bruce R.; Goldie, Sue J.; Weinstein, Milton C.; Losina, Elena; Zhang, Hong; Freedberg, Kenneth A.

2001-01-01

Objectives. This study was designed to examine the societal cost-effectiveness and the impact on government payers of earlier initiation of antiretroviral therapy for uninsured HIV-infected adults. Methods. A state-transition simulation model of HIV disease was used. Data were derived from the Multicenter AIDS Cohort Study, published randomized trials, and medical care cost estimates for all government payers and for Massachusetts, New York, and Florida. Results. Quality-adjusted life expectancy increased from 7.64 years with therapy initiated at 200 CD4 cells/μL to 8.21 years with therapy initiated at 500 CD4 cells/μL. Initiating therapy at 500 CD4/μL was a more efficient use of resources than initiating therapy at 200 CD4/μL and had an incremental cost-effectiveness ratio of $17 300 per quality-adjusted life-year gained, compared with no therapy. Costs to state payers in the first 5 years ranged from $5500 to $24 900 because of differences among the states in the availability of federal funds for AIDS drug assistance programs. Conclusions. Antiretroviral therapy initiated at 500 CD4 cells/μL is cost-effective from a societal perspective compared with therapy initiated later. States should consider Medicaid waivers to expand access to early therapy. PMID:11527782

Health care strategies to promote earlier presentation of symptomatic breast cancer: perspectives of women and family physicians

PubMed Central

Heisey, R.; Clemons, M.; Granek, L.; Fergus, K.; Hum, S.; Lord, B.; McCready, D.R.; Fitzgerald, B.

2011-01-01

Background Many women with symptoms suggestive of a breast cancer diagnosis delay presentation to their family physician. Although factors associated with delay have been well described, there is a paucity of data on strategies to mitigate delay. Objectives We conducted a qualitative research project to examine factors related to delay and to identify health care system changes that might encourage earlier presentation. Methods Individual semi-structured interviews were conducted with women who sought care 12 weeks or more after self-detection of breast cancer symptoms and with family physicians whose practices included patients meeting that criterion. Results The women and physicians both suggested a need for clearer screening mammography guidelines for women 40–49 years of age and for better messaging concerning breast awareness. The use of additional hopeful testimonials from breast cancer survivors were suggested to help dispel the notion of cancer as a “death sentence.” Educational initiatives were proposed, aimed at both increasing awareness of “non-lump” breast cancer symptoms and advising women that a previous benign diagnosis does not ensure that future symptoms are not cancer. Women wanted empathic nonjudgmental access to care. Improved methods to track compliance with screening mammography and with periodic health exams and access to a rapid diagnostic process were suggested. Conclusions A list of “at-risk situations for delay” in diagnosis of breast cancer was developed for physicians to assist in identifying women who might delay. Health care system changes actionable both at the health policy level and in the family physician’s office were identified to encourage earlier presentation of women with symptomatic breast cancer. PMID:21980254

Experimental and theoretical study of magnetohydrodynamic ship models.

PubMed

Cébron, David; Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe

2017-01-01

Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

Experimental and theoretical study of magnetohydrodynamic ship models

PubMed Central

Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe

2017-01-01

Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques. PMID:28665941

The HepHIV 2017 Conference in Malta: joining forces for the earlier diagnosis of HIV and viral hepatitis.

PubMed

Raben, D; Hoekstra, M; Sperle, I; Amato Gauci, A J; Gauci, C; West, B; Sullivan, A; Lazarus, J V; Platteau, T; Rockstroh, J K

2018-02-01

The objective of the article is to provide an overview of the results of the HepHIV 2017 Conference organized by the HIV in Europe initiative under the Maltese EU Presidency in January 2017. A thourough review of all conference presentations (oral and poster presentations) was performed to retrieve the key outcomes of the conference. The key result from the conference was a call to action summarising key priorities in HIV and viral hepatitis testing and linkage to care. This included improving monitoring of viral hepatitis and HIV, mixing testing strategies and ensuring policy support. The important contribution and outcomes of EU funded projects OptTEST and EuroHIVEdat was highlighted. An integrated approach to earlier testing and linkage to care across diseases is needed in Europe and the HepHIV conferences create an important forum to reach this aim. © 2018 British HIV Association.

A Hepatocellular Carcinoma Case in a Patient Who had Immunity to Hepatitis B Virus Earlier.

PubMed

Ates, Ihsan; Kaplan, Mustafa; Demirci, Selim; Altiparmak, Emin

2016-01-01

Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. Hepatitis B virus infection is one of the most important etilogical factors of HCC. In this case report, a patient with HCC previously infected and having ongoing immunity against hepatitis B virus will be discussed. Ates I, Kaplan M, Demirci S, Altiparmak E. A Hepatocellular Carcinoma Case in a Patient Who had Immunity to Hepatitis B Virus Earlier. Euroasian J Hepato-Gastroenterol 2016;6(1):82-83.

O+OH-->O(2)+H: A key reaction for interstellar chemistry. New theoretical results and comparison with experiment.

PubMed

Lique, F; Jorfi, M; Honvault, P; Halvick, P; Lin, S Y; Guo, H; Xie, D Q; Dagdigian, P J; Kłos, J; Alexander, M H

2009-12-14

We report extensive, fully quantum, time-independent (TID) calculations of cross sections at low collision energies and rate constants at low temperatures for the O+OH reaction, of key importance in the production of molecular oxygen in cold, dark, interstellar clouds and in the chemistry of the Earth's atmosphere. Our calculations are compared with TID calculations within the J-shifting approximation, with wave-packet calculations, and with quasiclassical trajectory calculations. The fully quantum TID calculations yield rate constants higher than those from the more approximate methods and are qualitatively consistent with a low-temperature extrapolation of earlier experimental values but not with the most recent experiments at the lowest temperatures.

Quantifying the economic value and quality of life impact of earlier influenza vaccination.

PubMed

Lee, Bruce Y; Bartsch, Sarah M; Brown, Shawn T; Cooley, Philip; Wheaton, William D; Zimmerman, Richard K

2015-03-01

Influenza vaccination is administered throughout the influenza disease season, even as late as March. Given such timing, what is the value of vaccinating the population earlier than currently being practiced? We used real data on when individuals were vaccinated in Allegheny County, Pennsylvania, and the following 2 models to determine the value of vaccinating individuals earlier (by the end of September, October, and November): Framework for Reconstructing Epidemiological Dynamics (FRED), an agent-based model (ABM), and FluEcon, our influenza economic model that translates cases from the ABM to outcomes and costs [health care and lost productivity costs and quality-adjusted life-years (QALYs)]. We varied the reproductive number (R0) from 1.2 to 1.6. Applying the current timing of vaccinations averted 223,761 influenza cases, $16.3 million in direct health care costs, $50.0 million in productivity losses, and 804 in QALYs, compared with no vaccination (February peak, R0 1.2). When the population does not have preexisting immunity and the influenza season peaks in February (R0 1.2-1.6), moving individuals who currently received the vaccine after September to the end of September could avert an additional 9634-17,794 influenza cases, $0.6-$1.4 million in direct costs, $2.1-$4.0 million in productivity losses, and 35-64 QALYs. Moving the vaccination of just children to September (R0 1.2-1.6) averted 11,366-1660 influenza cases, $0.6-$0.03 million in direct costs, $2.3-$0.2 million in productivity losses, and 42-8 QALYs. Moving the season peak to December increased these benefits, whereas increasing preexisting immunity reduced these benefits. Even though many people are vaccinated well after September/October, they likely are still vaccinated early enough to provide substantial cost-savings.

Using leg muscles as shock absorbers: theoretical predictions and experimental results of drop landing performance.

PubMed

Minetti, A E; Ardigò, L P; Susta, D; Cotelli, F

1998-12-01

The use of muscles as power dissipators is investigated in this study, both from the modellistic and the experimental points of view. Theoretical predictions of the drop landing manoeuvre for a range of initial conditions have been obtained by accounting for the mechanical characteristics of knee extensor muscles, the limb geometry and assuming maximum neural activation. Resulting dynamics have been represented in the phase plane (vertical displacement versus speed) to better classify the damping performance. Predictions of safe landing in sedentary subjects were associated to dropping from a maximum (feet) height of 1.6-2.0 m (about 11 m on the moon). Athletes can extend up to 2.6-3.0 m, while for obese males (m = 100 kg, standard stature) the limit should reduce to 0.9-1.3 m. These results have been calculated by including in the model the estimated stiffness of the 'global elastic elements' acting below the squat position. Experimental landings from a height of 0.4, 0.7, 1.1 m (sedentary males (SM) and male (AM) and female (AF) athletes from the alpine ski national team) showed dynamics similar to the model predictions. While the peak power (for a drop height of about 0.7 m) was similar in SM and AF (AM shows a +40% increase, about 33 W/kg), AF stopped the downward movement after a time interval (0.219 +/- 0.030 s) from touch-down 20% significantly shorter than SM. Landing strategy and the effect of anatomical constraints are discussed in the paper.

The Earlier the Better? Taking the AP® in 10th Grade. Research Report No. 2012-10

ERIC Educational Resources Information Center

Rodriguez, Awilda; McKillip, Mary E. M.; Niu, Sunny X.

2013-01-01

In this report, the authors examine the impact of scoring a 1 or 2 on an AP® Exam in 10th grade on later AP Exam participation and performance. As access to AP courses increases within and across schools, a growing number of students are taking AP courses and exams in the earlier grades of high school. Using a matched sample of AP and no-AP…

The Nature and Meaning of Body Concepts in Everyday Language and Theoretical Discourse.

PubMed

Pollio, Howard R; Finn, Mike; Custer, Morgun

2016-06-01

Within phenomenological philosophy four topics, (1) Body, (2) Time, (3) Others and the Social Order and (4) World serve as the major contexts in which human perception, action and reflection take place. At present only three of these domains have been studied from an empirical perspective, leaving Body as the one domain requiring further analysis. Given this state of affairs, the purpose of the present study is to determine the everyday and theoretical meanings of body. To accomplish this task participants coded randomly selected body- related words into groups on the basis of having similar meanings. Once these groupings were established they were then evaluated by statistical clustering and multidimensional scaling procedures. Results indicated that it was possible to define the everyday meaning of the human experience of the human body in terms of the following set of themes: (1) inside/outside, (2) visible/not visible, (3) vitality and activity, (4) instrument and object and (5) appearance and self-expression. Concerns about the representativeness of the words studied led to the development and use of individual word pools from which a set of 50 partially different words was randomly selected for each participant. Results indicated little difference between themes produced in the present study when compared with those of an earlier study. The specific themes derived from the present study were then related to embodiment issues as reflected in the philosophical writings of Merleau-Ponty, the psycholinguistic analyses of Lakoff and Johnson and experimental psychology.

Experimental and theoretical characterization of an AC electroosmotic micromixer.

PubMed

Sasaki, Naoki; Kitamori, Takehiko; Kim, Haeng-Boo

2010-01-01

We have reported on a novel microfluidic mixer based on AC electroosmosis. To elucidate the mixer characteristics, we performed detailed measurements of mixing under various experimental conditions including applied voltage, frequency and solution viscosity. The results are discussed through comparison with results obtained from a theoretical model of AC electroosmosis. As predicted from the theoretical model, we found that a larger voltage (approximately 20 V(p-p)) led to more rapid mixing, while the dependence of the mixing on frequency (1-5 kHz) was insignificant under the present experimental conditions. Furthermore, the dependence of the mixing on viscosity was successfully explained by the theoretical model, and the applicability of the mixer in viscous solution (2.83 mPa s) was confirmed experimentally. By using these results, it is possible to estimate the mixing performance under given conditions. These estimations can provide guidelines for using the mixer in microfluidic chemical analysis.

Infantilism: Theoretical Construct and Operationalization

ERIC Educational Resources Information Center

Sabelnikova, Y. V.; Khmeleva, N. L.

2018-01-01

The aim of this article is to define and operationalize the construct of infantilism. The methods of theoretical research involve analysis and synthesis. Age and content criteria are analyzed for childhood and adulthood. Infantile traits in an adult are described. Results: The characteristics of adult infantilism in the modern world are defined,…

Association between severe dorsolateral prefrontal dysfunction during random number generation and earlier onset in schizophrenia.

PubMed

Koike, Shinsuke; Takizawa, Ryu; Nishimura, Yukika; Marumo, Kohei; Kinou, Masaru; Kawakubo, Yuki; Rogers, Mark A; Kasai, Kiyoto

2011-08-01

Schizophrenia involves impairment in attention, working memory and executive processes associated with prefrontal cortical function, an essential contributor of social functioning. Age at onset is a major factor for predicting social outcome in schizophrenia. In clinical settings, we need an objective assessment tool for evaluating prefrontal function and social outcome. Participants included 22 right-handed patients with schizophrenia and 40 gender- and age-matched healthy controls. We used a 52-channel near-infrared spectroscopy (NIRS) instrument to measure oxygenated haemoglobin ([oxy-Hb]) changes over the prefrontal cortex during a random number generation (RNG) task. In healthy controls, we found significant [oxy-Hb] increase in the bilateral dorsolateral (DLPFC; BA9 and BA46) and ventrolateral prefrontal cortex (VLPFC; BA44, 45 and 47). The patients with schizophrenia showed significantly smaller activation than the healthy controls in the same approximate regions. In the patient group, a smaller [oxy-Hb] increase in the right DLPFC region (BA9) was significantly correlated with earlier age at onset. NIRS can detect prefrontal cortical dysfunction associated with an executive task, which was coupled with earlier age at onset in schizophrenia. Multichannel NIRS, a non-invasive and user-friendly instrument, may be useful in evaluating cognitive function and social outcome in clinical settings in psychiatry. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Combined circulating tumor DNA and protein biomarker-based liquid biopsy for the earlier detection of pancreatic cancers

PubMed Central

Cohen, Joshua D.; Javed, Ammar A.; Thoburn, Christopher; Wong, Fay; Tie, Jeanne; Gibbs, Peter; Schmidt, C. Max; Yip-Schneider, Michele T.; Allen, Peter J.; Schattner, Mark; Brand, Randall E.; Singhi, Aatur D.; Petersen, Gloria M.; Hong, Seung-Mo; Kim, Song Cheol; Falconi, Massimo; Doglioni, Claudio; Weiss, Matthew J.; Ahuja, Nita; He, Jin; Makary, Martin A.; Maitra, Anirban; Hanash, Samir M.; Dal Molin, Marco; Wang, Yuxuan; Li, Lu; Ptak, Janine; Dobbyn, Lisa; Schaefer, Joy; Silliman, Natalie; Popoli, Maria; Goggins, Michael G.; Hruban, Ralph H.; Wolfgang, Christopher L.; Klein, Alison P.; Tomasetti, Cristian; Papadopoulos, Nickolas; Kinzler, Kenneth W.; Vogelstein, Bert; Lennon, Anne Marie

2017-01-01

The earlier diagnosis of cancer is one of the keys to reducing cancer deaths in the future. Here we describe our efforts to develop a noninvasive blood test for the detection of pancreatic ductal adenocarcinoma. We combined blood tests for KRAS gene mutations with carefully thresholded protein biomarkers to determine whether the combination of these markers was superior to any single marker. The cohort tested included 221 patients with resectable pancreatic ductal adenocarcinomas and 182 control patients without known cancer. KRAS mutations were detected in the plasma of 66 patients (30%), and every mutation found in the plasma was identical to that subsequently found in the patient’s primary tumor (100% concordance). The use of KRAS in conjunction with four thresholded protein biomarkers increased the sensitivity to 64%. Only one of the 182 plasma samples from the control cohort was positive for any of the DNA or protein biomarkers (99.5% specificity). This combinatorial approach may prove useful for the earlier detection of many cancer types. PMID:28874546

Theoretical Characterizaiton of Visual Signatures

NASA Astrophysics Data System (ADS)

Kashinski, D. O.; Chase, G. M.; di Nallo, O. E.; Scales, A. N.; Vanderley, D. L.; Byrd, E. F. C.

2015-05-01

We are investigating the accuracy of theoretical models used to predict the visible, ultraviolet, and infrared spectra, as well as other properties, of product materials ejected from the muzzle of currently fielded systems. Recent advances in solid propellants has made the management of muzzle signature (flash) a principle issue in weapons development across the calibers. A priori prediction of the electromagnetic spectra of formulations will allow researchers to tailor blends that yield desired signatures and determine spectrographic detection ranges. Quantum chemistry methods at various levels of sophistication have been employed to optimize molecular geometries, compute unscaled vibrational frequencies, and determine the optical spectra of specific gas-phase species. Electronic excitations are being computed using Time Dependent Density Functional Theory (TD-DFT). A full statistical analysis and reliability assessment of computational results is currently underway. A comparison of theoretical results to experimental values found in the literature is used to assess any affects of functional choice and basis set on calculation accuracy. The status of this work will be presented at the conference. Work supported by the ARL, DoD HPCMP, and USMA.

Patient centredness in integrated care: results of a qualitative study based on a systems theoretical framework.

PubMed

Lüdecke, Daniel

2014-10-01

Health care providers seek to improve patient-centred care. Due to fragmentation of services, this can only be achieved by establishing integrated care partnerships. The challenge is both to control costs while enhancing the quality of care and to coordinate this process in a setting with many organisations involved. The problem is to establish control mechanisms, which ensure sufficiently consideration of patient centredness. Seventeen qualitative interviews have been conducted in hospitals of metropolitan areas in northern Germany. The documentary method, embedded into a systems theoretical framework, was used to describe and analyse the data and to provide an insight into the specific perception of organisational behaviour in integrated care. The findings suggest that integrated care partnerships rely on networks based on professional autonomy in the context of reliability. The relationships of network partners are heavily based on informality. This correlates with a systems theoretical conception of organisations, which are assumed autonomous in their decision-making. Networks based on formal contracts may restrict professional autonomy and competition. Contractual bindings that suppress the competitive environment have negative consequences for patient-centred care. Drawbacks remain due to missing self-regulation of the network. To conclude, less regimentation of integrated care partnerships is recommended.

Earlier Detection of Tumor Treatment Response Using Magnetic Resonance Diffusion Imaging with Oscillating Gradients

PubMed Central

Colvin, Daniel C.; Loveless, Mary E.; Does, Mark D.; Yue, Zou; Yankeelov, Thomas E.; Gore, John C.

2011-01-01

An improved method for detecting early changes in tumors in response to treatment, based on a modification of diffusion-weighted magnetic resonance imaging, has been demonstrated in an animal model. Early detection of therapeutic response in tumors is important both clinically and in pre-clinical assessments of novel treatments. Non-invasive imaging methods that can detect and assess tumor response early in the course of treatment, and before frank changes in tumor morphology are evident, are of considerable interest as potential biomarkers of treatment efficacy. Diffusion-weighted magnetic resonance imaging is sensitive to changes in water diffusion rates in tissues that result from structural variations in the local cellular environment, but conventional methods mainly reflect changes in tissue cellularity and do not convey information specific to micro-structural variations at sub-cellular scales. We implemented a modified imaging technique using oscillating gradients of the magnetic field for evaluating water diffusion rates over very short spatial scales that are more specific for detecting changes in intracellular structure that may precede changes in cellularity. Results from a study of orthotopic 9L gliomas in rat brains indicate that this method can detect changes as early as 24 hours following treatment with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), when conventional approaches do not find significant effects. These studies suggest that diffusion imaging using oscillating gradients may be used to obtain an earlier indication of treatment efficacy than previous magnetic resonance imaging methods. PMID:21190804

Colorectal cancer occurs earlier in those exposed to tobacco smoke: implications for screening

PubMed Central

Mahoney, Martin C.; Cummings, K. Michael; Michalek, Arthur M.; Reid, Mary E.; Moysich, Kirsten B.; Hyland, Andrew

2011-01-01

Background Colorectal cancer (CRC) is the third most common cancer in the USA. While various lifestyle factors have been shown to alter the risk for colorectal cancer, recommendations for the early detection of CRC are based only on age and family history. Methods This case-only study examined the age at diagnosis of colorectal cancer in subjects exposed to tobacco smoke. Subjects included all patients who attended RPCI between 1957 and 1997, diagnosed with colorectal cancer, and completed an epidemiologic questionnaire. Adjusted linear regression models were calculated for the various smoking exposures. Results Of the 3,540 cases of colorectal cancer, current smokers demonstrated the youngest age of CRC onset (never: 64.2 vs. current: 57.4, P < 0.001) compared to never smokers, followed by recent former smokers. Among never smokers, individuals with past second-hand smoke exposure were diagnosed at a significantly younger age compared to the unexposed. Conclusion This study found that individuals with heavy, long-term tobacco smoke exposure were significantly younger at the time of CRC diagnosis compared to lifelong never smokers. The implication of this finding is that screening for colorectal cancer, which is recommended to begin at age 50 years for persons at average risk should be initiated 5–10 years earlier for persons with a significant lifetime history of exposure to tobacco smoke. PMID:18264728

Can Biannual Ultrasound Surveillance Detect Smaller Second Cancers or Detect Cancers Earlier in Patients with Breast Cancer History?

PubMed

You, Jai Kyung; Song, Mi Kyung; Kim, Min Jung; Kim, Eun-Kyung; Moon, Hee Jung; Youk, Ji Hyun; Yoon, Jung Hyun; Park, Vivian Youngjean; Park, Seho; Kim, Seung Il; Park, Byeong-Woo

2018-07-01

The aim of the work described here was to evaluate whether surveillance with biannual ultrasound (US) plus annual mammography (biannual group) for women with a history of breast cancer surgery results in earlier detection or in the detection of smaller second cancers than annual US plus mammography (annual group). Additionally, we compared the prevalence of distant metastases or palpable second cancers between the biannual and annual groups. The institutional review board of our institution approved this retrospective study, and patient consent was waived. Between January 2011 and December 2012, we retrospectively reviewed the clinical and imaging follow-up of 3023 patients with mammographic and US surveillance after breast cancer surgery to assess second cancers detected by local surveillance (locoregional recurrence, contralateral breast cancer or distant metastasis). The biannual and annual groups were divided with respect to the mean surveillance interval and compared with respect to clinicopathologic findings. Multivariable logistic regression with propensity score methods was used to examine the effect of the type of surveillance on outcomes. As for the size of the second cancer, no difference was seen between the biannual and annual groups (12.8 ± 6.6 mm vs. 14.1 ± 7.1 mm, p = 0.461); neither was there a significant difference between the groups in the presence of symptoms at the time of diagnosis of the second cancer (17.0% [8/47] vs. 10% [2/20], p = 0.711). Regardless of detection by local surveillance, the prevalence of distant metastases did not differ between the two groups (1.1% [27/2370] vs. 1.0% [7/653], p = 0.88) on univariate or multivariate analysis. The results of our retrospective study indicate that second cancers detected by biannual US surveillance in patients with a history of breast cancer surgery are not smaller and do not occur earlier than those detected by annual US surveillance. However, a randomized

Theoretical characterization of the potential energy surface for NH + NO

NASA Technical Reports Server (NTRS)

Walch, Stephen P.

1992-01-01

The potential energy surface (PES) for NH + NO was characterized using complete active space self-consistent field (CASSCF) gradient calculations to determine the stationary point geometries and frequencies followed by CASSCF/internally contracted configuration interaction (CCI) calculations to refine the energetics. The present results are in qualitative accord with the BAC-MP4 calculations, but there are differences as large as 8 kcal/mol in the detailed energetics. Addition of NH to NO on a (2)A' surface, which correlated with N2 + OH or H + N2O products, involves barriers of 3.2 kcal/mol (trans) and 6.3 kcal/mol (cis). Experimental evidence for these barriers is found in earlier works. The (2)A' surface has no barrier to addition, but does not correlate with products. Surface crossings between the barrierless (2)A' surface and the (2)A' surface may be important. Production of N2 + OH products is predicted to occur via a planar saddle point of (2)A' symmetry. This is in accord with the preferential formation of II(A') lambda doublet levels of OH in earlier experiments. Addition of NH (1)delta to NO is found to occur on an excited state surface and is predicted to lead to N2O product as observed in earlier works.

Theoretical and Applied Implications of Precisely Measuring Learning Rates

ERIC Educational Resources Information Center

Skinner, Christopher H.

2008-01-01

Nist and Joseph (2008) have confirmed earlier research showing that adding and interspersing a large number of time-consuming learning trials targeting known items (e.g., incremental rehearsal (IR) or interspersal) retards student learning rates. In addition, their current study has confirmed earlier research that adding and interspersing known…

A Hepatocellular Carcinoma Case in a Patient Who had Immunity to Hepatitis B Virus Earlier

PubMed Central

Kaplan, Mustafa; Demirci, Selim; Altiparmak, Emin

2016-01-01

ABSTRACT Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. Hepatitis B virus infection is one of the most important etilogical factors of HCC. In this case report, a patient with HCC previously infected and having ongoing immunity against hepatitis B virus will be discussed. How to cite this article Ates I, Kaplan M, Demirci S, Altiparmak E. A Hepatocellular Carcinoma Case in a Patient Who had Immunity to Hepatitis B Virus Earlier. Euroasian J Hepato-Gastroenterol 2016;6(1):82-83. PMID:29201732

Introduction to Theoretical Modelling

NASA Astrophysics Data System (ADS)

Davis, Matthew J.; Gardiner, Simon A.; Hanna, Thomas M.; Nygaard, Nicolai; Proukakis, Nick P.; Szymańska, Marzena H.

2013-02-01

We briefly overview commonly encountered theoretical notions arising in the modelling of quantum gases, intended to provide a unified background to the `language' and diverse theoretical models presented elsewhere in this book, and aimed particularly at researchers from outside the quantum gases community.

A comparison of experimental and theoretical results for rotordynamic coefficients of four annular gas seals

NASA Technical Reports Server (NTRS)

Childs, D. W.; Nelson, C. C.; Elrod, D.; Nicks, C.

1985-01-01

The test facility and initial test program developed to experimentally measure the fluid forces induced by annular gas seals is described. A comparison of theoretically predicted and experimentally obtained data for smooth and honeycomb seals is provided. And a comparison of experimental data from the tests of three smooth-rotor/smooth-stator seals is provided. The leakage of the working fluid through the seal, the pressure gradient along the seal length, entrance pressure-loss data, and rotordynamic coefficients provide a basis for comparison. A short discussion on seal theory is included, and various rotordynamic coefficient identification schemes are described.

NMR-based fecal metabolomics fingerprinting as predictors of earlier diagnosis in patients with colorectal cancer.

PubMed

Lin, Yan; Ma, Changchun; Liu, Chengkang; Wang, Zhening; Yang, Jurong; Liu, Xinmu; Shen, Zhiwei; Wu, Renhua

2016-05-17

Colorectal cancer (CRC) is a growing cause of mortality in developing countries, warranting investigation into its earlier detection for optimal disease management. A metabolomics based approach provides potential for noninvasive identification of biomarkers of colorectal carcinogenesis, as well as dissection of molecular pathways of pathophysiological conditions. Here, proton nuclear magnetic resonance spectroscopy (1HNMR) -based metabolomic approach was used to profile fecal metabolites of 68 CRC patients (stage I/II=20; stage III=25 and stage IV=23) and 32 healthy controls (HC). Pattern recognition through principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) was applied on 1H-NMR processed data for dimension reduction. OPLS-DA revealed that each stage of CRC could be clearly distinguished from HC based on their metabolomic profiles. Successive analyses identified distinct disturbances to fecal metabolites of CRC patients at various stages, compared with those in cancer free controls, including reduced levels of acetate, butyrate, propionate, glucose, glutamine, and elevated quantities of succinate, proline, alanine, dimethylglycine, valine, glutamate, leucine, isoleucine and lactate. These altered fecal metabolites potentially involved in the disruption of normal bacterial ecology, malabsorption of nutrients, increased glycolysis and glutaminolysis. Our findings revealed that the fecal metabolic profiles of healthy controls can be distinguished from CRC patients, even in the early stage (stage I/II), highlighting the potential utility of NMR-based fecal metabolomics fingerprinting as predictors of earlier diagnosis in CRC patients.

NMR-based fecal metabolomics fingerprinting as predictors of earlier diagnosis in patients with colorectal cancer

PubMed Central

Lin, Yan; Ma, Changchun; Liu, Chengkang; Wang, Zhening; Yang, Jurong; Liu, Xinmu; Shen, Zhiwei; Wu, Renhua

2016-01-01

Colorectal cancer (CRC) is a growing cause of mortality in developing countries, warranting investigation into its earlier detection for optimal disease management. A metabolomics based approach provides potential for noninvasive identification of biomarkers of colorectal carcinogenesis, as well as dissection of molecular pathways of pathophysiological conditions. Here, proton nuclear magnetic resonance spectroscopy (1HNMR) -based metabolomic approach was used to profile fecal metabolites of 68 CRC patients (stage I/II=20; stage III=25 and stage IV=23) and 32 healthy controls (HC). Pattern recognition through principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) was applied on 1H-NMR processed data for dimension reduction. OPLS-DA revealed that each stage of CRC could be clearly distinguished from HC based on their metabolomic profiles. Successive analyses identified distinct disturbances to fecal metabolites of CRC patients at various stages, compared with those in cancer free controls, including reduced levels of acetate, butyrate, propionate, glucose, glutamine, and elevated quantities of succinate, proline, alanine, dimethylglycine, valine, glutamate, leucine, isoleucine and lactate. These altered fecal metabolites potentially involved in the disruption of normal bacterial ecology, malabsorption of nutrients, increased glycolysis and glutaminolysis. Our findings revealed that the fecal metabolic profiles of healthy controls can be distinguished from CRC patients, even in the early stage (stage I/II), highlighting the potential utility of NMR-based fecal metabolomics fingerprinting as predictors of earlier diagnosis in CRC patients. PMID:27107423

Introduction of a theoretical splashing degree to assess the performance of low-viscosity oils in filling of capsules.

PubMed

Niederquell, Andreas; Kuentz, Martin

2011-03-01

These days an alternative to soft capsules is liquid-filled hard capsules. Their filling technology was investigated earlier with highly viscous formulations, while hardly any academic research focused on low-viscosity systems. Accordingly, this work addressed the filling of such oils that are splashing during the dosing process. It was aimed to first study capsule filling, using middle-chain triglycerides as reference oil, in order to then evaluate the concept of a new theoretical splashing degree for different oils. A laboratory-scale filling machine was used that included capsule sealing. Thus, the liquid encapsulation by microspray technology was employed to seal the dosage form. As a result of the study with reference oil, the filling volume and the temperature were found to be significant for the rate of leaking capsules. The filling volume was also important for weight variability of the capsules. However, most critical for this variability was the diameter of the filling nozzle. We proposed a power law for the coefficient of weight variability as a function of the nozzle diameter and the obtained exponent agreed with the proposed theory. Subsequently, a comparison of different oils revealed that the relative splashing degree shared a correlation with the coefficient of the capsule weight variability (Pearson product moment correlation of r=0.990). The novel theoretical concept was therefore found to be predictive for weight variability of the filled capsules. Finally, guidance was provided for the process development of liquid-filled capsules using low-viscosity oils. © 2011 American Association of Pharmaceutical Scientists

Theoretical models for the combustion of alloyable materials

NASA Astrophysics Data System (ADS)

Armstrong, Robert

1992-09-01

The purpose of this work is to extend a theoretical model of layered (laminar) media for SHS combustion presented in an earlier article [1] to explore possible mechanisms for after-burning in SHS ( i.e., gasless) combustion. As before, our particular interest is how the microscopic geometry of the solid reactants is reflected in the combustion wave and in the reaction product. The model is constructed from alternating lamina of two pure reactants that interdiffuse exothermically to form a product. Here, the laminar model is extended to contain layers of differing thicknesses. Using asymptotic theory, it was found that under certain conditions, the combustion wave can become “detached,” and an initial thin flame propagates through the media, leaving a slower, thicker flame following behind ( i.e., afterburning). Thin laminae are consumed in the initial flame and are thick in the secondary. The thin flame has a width determined by the inverse of the activation energy of diffusion, as found previously. The width of the afterburning zone, however, is determined by the absolute time of diffusion for the thicker laminae. Naturally, when the laminae are all the same thickness, there is only one thin flame. The condition for the appearance of afterburning is found to be contingent on the square of the ratio of smallestto-largest thicknesses being considerably less than unity.

Onset of rigor mortis is earlier in red muscle than in white muscle.

PubMed

Kobayashi, M; Takatori, T; Nakajima, M; Sakurada, K; Hatanaka, K; Ikegaya, H; Matsuda, Y; Iwase, H

2000-01-01

Rigor mortis is thought to be related to falling ATP levels in muscles postmortem. We measured rigor mortis as tension determined isometrically in three rat leg muscles in liquid paraffin kept at 37 degrees C or 25 degrees C--two red muscles, red gastrocnemius (RG) and soleus (SO) and one white muscle, white gastrocnemius (WG). Onset, half and full rigor mortis occurred earlier in RG and SO than in WG both at 37 degrees C and at 25 degrees C even though RG and WG were portions of the same muscle. This suggests that rigor mortis directly reflects the postmortem intramuscular ATP level, which decreases more rapidly in red muscle than in white muscle after death. Rigor mortis was more retarded at 25 degrees C than at 37 degrees C in each type of muscle.

The Chinese Visible Human (CVH) datasets incorporate technical and imaging advances on earlier digital humans

PubMed Central

Zhang, Shao-Xiang; Heng, Pheng-Ann; Liu, Zheng-Jin; Tan, Li-Wen; Qiu, Ming-Guo; Li, Qi-Yu; Liao, Rong-Xia; Li, Kai; Cui, Gao-Yu; Guo, Yan-Li; Yang, Xiao-Ping; Liu, Guang-Jiu; Shan, Jing-Lu; Liu, Ji-Jun; Zhang, Wei-Guo; Chen, Xian-Hong; Chen, Jin-Hua; Wang, Jian; Chen, Wei; Lu, Ming; You, Jian; Pang, Xue-Li; Xiao, Hong; Xie, Yong-Ming; Cheng, Jack Chun-Yiu

2004-01-01

We report the availability of a digitized Chinese male and a digitzed Chinese female typical of the population and with no obvious abnormalities. The embalming and milling procedures incorporate three technical improvements over earlier digitized cadavers. Vascular perfusion with coloured gelatin was performed to facilitate blood vessel identification. Embalmed cadavers were embedded in gelatin and cryosectioned whole so as to avoid section loss resulting from cutting the body into smaller pieces. Milling performed at −25 °C prevented small structures (e.g. teeth, concha nasalis and articular cartilage) from falling off from the milling surface. The male image set (.tiff images each of 36 Mb) has a section resolution of 3072 × 2048 pixels (∼170 μm, the accompanying magnetic resonance imaging and computer tomography data have a resolution of 512 × 512, i.e. ∼440 μm). The Chinese Visible Human male and female datasets are available at http://www.chinesevisiblehuman.com. (The male is 90.65 Gb and female 131.04 Gb). MPEG videos of direct records of real-time volume rendering are at: http://www.cse.cuhk.edu.hk/~crc PMID:15032906

Earlier anal sexarche and co-occurring sexual risk are associated with current HIV-related risk behaviors among an online sample of men who have sex with men in Asia

PubMed Central

Cheung, Doug H.; Suharlim, Christian; Guadamuz, Thomas E.; Lim, Sin How; Koe, Stuart; Wei, Chongyi

2014-01-01

Studies of heterosexual populations across the globe and men who have sex with men (MSM) in a few developed countries showed that earlier sexual debut (sexarche) was associated with higher levels of co-occurring and subsequent HIV risk behaviors. We examined the relationships between earlier anal sexarche, unprotected earlier anal sexarche and current HIV risks among MSM from Asia. A cross-sectional online survey was conducted among MSM (N = 10,826) in Asia in 2010. Bivariate and multivariable logistic regressions were used to identify co-occurring (i.e., sexual experiences during sexarche) and current HIV-related risk factors (i.e., past six months) associated with earlier anal sexarche (before the age of 18) and unprotected earlier anal sexarche, respectively. Earlier anal sexarche was significantly associated with lack of condom use, being anal receptive or both receptive and insertive, and having a partner who were older during sexarche. It was also associated with current HIV-related risk behaviors including having multiple male sexual partners, having been paid for sex, and increased frequencies of recreational drug use. Unprotected earlier anal sexarche was significantly associated with inconsistent condom use in the past the six months. Improved and culturally sensitive sex education at schools should be included in national and regional HIV/AIDS prevention programming and policies in Asia. Such sex education programs should incorporate curriculum that address sexuality, sexual orientation, and sexual behaviors beyond those related to reproductive health. PMID:24920344

Earlier anal sexarche and co-occurring sexual risk are associated with current HIV-related risk behaviors among an online sample of men who have sex with men in Asia.

PubMed

Cheung, Doug H; Suharlim, Christian; Guadamuz, Thomas E; Lim, Sin How; Koe, Stuart; Wei, Chongyi

2014-12-01

Studies of heterosexual populations across the globe and men who have sex with men (MSM) in a few developed countries showed that earlier sexual debut (sexarche) was associated with higher levels of co-occurring and subsequent HIV risk behaviors. We examined the relationships between earlier anal sexarche, unprotected earlier anal sexarche and current HIV risks among MSM from Asia. A cross-sectional online survey was conducted among MSM (N = 10,826) in Asia in 2010. Bivariate and multivariable logistic regressions were used to identify co-occurring (i.e., sexual experiences during sexarche) and current HIV-related risk factors (i.e., past 6 months) associated with earlier anal sexarche (before the age of 18) and unprotected earlier anal sexarche, respectively. Earlier anal sexarche was significantly associated with lack of condom use, being anal receptive or both receptive and insertive, and having a partner who were older during sexarche. It was also associated with current HIV-related risk behaviors including having multiple male sexual partners, having been paid for sex, and increased frequencies of recreational drug use. Unprotected earlier anal sexarche was significantly associated with inconsistent condom use in the past the 6 months. Improved and culturally sensitive sex education at schools should be included in national and regional HIV/AIDS prevention programming and policies in Asia. Such sex education programs should incorporate curriculum that address sexuality, sexual orientation, and sexual behaviors beyond those related to reproductive health.

Infliximab for uveitis of Behçet's syndrome: a trend for earlier initiation.

PubMed

Guzelant, Gul; Ucar, Didar; Esatoglu, Sinem Nihal; Hatemi, Gulen; Ozyazgan, Yilmaz; Yurdakul, Sebahattin; Seyahi, Emire; Yazici, Hasan; Hamuryudan, Vedat

2017-01-01

The prognosis of uveitis in Behçet's syndrome (BS) has improved over decades. Whether this is related to the use of more aggressive management strategies is not known. This is a retrospective study of BS patients who received infliximab (IFX) for refractory eye disease between 2003-2015. The patients were divided into two groups according to the date of onset of in IFX treatment as before and after 2013. We compared the two groups in terms of disease characteristics at the onset of IFX treatment and response to treatment. There were 43 patients in the old and 14 patients in the new group. The duration of uveitis and previous immunosuppressive treatment before the initiation of IFX were significantly shorter in the new group compared to the old group (p=0.043 and p=0.028, respectively). The baseline visual acuity (VA) at the initiation of IFX was better in the new group, but this was only significant for the left eye. Treatment with IFX was effective in both groups in preserving VA and this was more pronounced in the new group. Attack frequency under IFX was significantly lower in the new group (p<0.001). IFX seems to be initiated earlier and also in less severe cases during the course of BS uveitis than before. Despite the few numbers of patients and relatively short duration of follow-up, our results give a hint that this change has improved the outcome.

Can social media data lead to earlier detection of drug‐related adverse events?

PubMed Central

Cremieux, Pierre; Audenrode, Marc Van; Vekeman, Francis; Karner, Paul; Zhang, Haimin; Greenberg, Paul

2016-01-01

Abstract Purpose To compare the patient characteristics and the inter‐temporal reporting patterns of adverse events (AEs) for atorvastatin (Lipitor®) and sibutramine (Meridia®) in social media (AskaPatient.com) versus the FDA Adverse Event Reporting System (FAERS). Methods We identified clinically important AEs associated with atorvastatin (muscle pain) and sibutramine (cardiovascular AEs), compared their patterns in social media postings versus FAERS and used Granger causality tests to assess whether social media postings were useful in forecasting FAERS reports. Results We analyzed 998 and 270 social media postings between 2001 and 2014, 69 003 and 7383 FAERS reports between 1997 and 2014 for atorvastatin and sibutramine, respectively. Social media reporters were younger (atorvastatin: 53.9 vs. 64.0 years, p < 0.001; sibutramine: 36.8 vs. 43.8 years, p < 0.001). Social media reviews contained fewer serious AEs (atorvastatin, pain: 2.5% vs. 38.2%; sibutramine, cardiovascular issues: 7.9% vs. 63.0%; p < 0.001 for both) and concentrated on fewer types of AEs (proportion comprising the top 20 AEs: atorvastatin, 88.7% vs. 55.4%; sibutramine, 86.3% vs. 65.4%) compared with FAERS. While social media sibutramine reviews mentioning cardiac issues helped predict those in FAERS 11 months later (p < 0.001), social media atorvastatin reviews did not help predict FAERS reports. Conclusions Social media AE reporters were younger and focused on less‐serious and fewer types of AEs than FAERS reporters. The potential for social media to provide earlier indications of AEs compared with FAERS is uncertain. Our findings highlight some of the promises and limitations of online social media versus conventional pharmacovigilance sources and the need for careful interpretation of the results. © 2016 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd. PMID:27601271

Radiation effects on space-based stellar photometry: theoretical models and empirical results for CoRoT Space Telescope

NASA Astrophysics Data System (ADS)

Pinheiro da Silva, L.; Rolland, G.; Lapeyrere, V.; Auvergne, M.

2008-03-01

Convection, Rotation and planetary Transits (CoRoT) is a space mission dedicated to stellar seismology and the search for extrasolar planets. Both scientific programs are based on very high precision photometry and require long, uninterrupted observations. The instrument is based on an afocal telescope and a wide-field camera, consisting of four E2V-4280 CCD devices. This set is mounted on a recurrent platform for insertion in low Earth orbit. The CoRoT satellite has been recently launched for a nominal mission duration of three years. In this work, we discuss the impact of space radiation on CoRoT CCDs, in sight of the in-flight characterization results obtained during the satellite's commissioning phase, as well as the very first observational data. We start by describing the population of trapped particles at the satellite altitude, and by presenting a theoretical prediction for the incoming radiation fluxes seen by the CCDs behind shielding. Empirical results regarding particle impact rates and their geographical distribution are then presented and discussed. The effect of particle impacts is also statistically characterized, with respect to the ionizing energy imparted to the CCDs and the size of impact trails. Based on these results, we discuss the effects of space radiation on precise and time-resolved stellar photometry from space. Finally, we present preliminary results concerning permanent radiation damage on CoRoT CCDs, as extrapolated from the data available at the beginning of the satellite's lifetime.

Earlier flowering did not alter pollen limitation in an early flowering shrub under short-term experimental warming.

PubMed

Pan, Cheng-Chen; Feng, Qi; Zhao, Ha-Lin; Liu, Lin-De; Li, Yu-Lin; Li, Yu-Qiang; Zhang, Tong-Hui; Yu, Xiao-Ya

2017-06-05

In animal pollinated plants, phenological shifts caused by climate change may have important ecological consequences. However, no empirical evidence exists at present on the consequences that flowering phenology shifts have on the strength of pollen limitation under experimental warming. Here, we investigated the effects of experimental warming on flowering phenology, flower density, reproductive success, and pollen limitation intensity in Caragana microphylla and evaluated whether earlier flowering phenology affected plant reproduction and the level of pollen limitation using warmed and unwarmed open top chambers in the Horqin Sandy Land of Inner Mongolia, northern China. The results of this study indicated that artificial warming markedly advanced flower phenology rather than extending the duration of the flowering. Additionally, warming was found to significantly reduce flower density which led to seed production reduction, since there were insignificant effects observed on fruit set and seed number per fruit. Experimental floral manipulations showed that warming did not affect pollen limitation. These results revealed the negative effects of advanced phenology induced by warming on flower density and reproductive output, as well as the neutral effects on reproductive success and pollen limitation intensity of long surviving plants.

Age of diagnosis of breast cancer in china: almost 10 years earlier than in the United States and the European union.

PubMed

Song, Qing-Kun; Li, Jing; Huang, Rong; Fan, Jin-Hu; Zheng, Rong-Shou; Zhang, Bao-Ning; Zhang, Bin; Tang, Zhong-Hua; Xie, Xiao-Ming; Yang, Hong-Jian; He, Jian-Jun; Li, Hui; Li, Jia-Yuan; Qiao, You-Lin; Chen, Wan-Qing

2014-01-01

The study aimed to describe the age distribution of breast cancer diagnosis among Chinese females for comparison with the United States and the European Union, and provide evidence for the screening target population in China. Median age was estimated from hospital databases from 7 tertiary hospitals in China. Population-based data in China, United States and European Union was extracted from the National Central Cancer Registry, SEER program and GLOBOCAN 2008, respectively. Age-standardized distribution of breast cancer at diagnosis in the 3 areas was estimated based on the World Standard Population 2000. The median age of breast cancer at diagnosis was around 50 in China, nearly 10 years earlier than United States and European Union. The diagnosis age in China did not vary between subgroups of calendar year, region and pathological characteristics. With adjustment for population structure, median age of breast cancer at diagnosis was 50~54 in China, but 55~59 in United States and European Union. The median diagnosis age of female breast cancer is much earlier in China than in the United States and the European Union pointing to racial differences in genetics and lifestyle. Screening programs should start at an earlier age for Chinese women and age disparities between Chinese and Western women warrant further studies.

Decreased length of stay and earlier oral feeding associated with standardized postoperative clinical care for total gastrectomies at a cancer center.

PubMed

Selby, Luke V; Rifkin, Marissa B; Yoon, Sam S; Ariyan, Charlotte E; Strong, Vivian E

2016-09-01

Standardization of postoperative care has been shown to decrease postoperative length of stay. In June 2009, we standardized postoperative care for all gastrectomies at our institution. Four years' worth of total gastrectomies (2 years prior to standardization and 2 years after standardization) were reviewed to determine the effect of standardization on postoperative care, length of stay, complications, and readmissions. Between June 2007 and July 2011, 99 patients underwent curative intent open total gastrectomy: 51 patients prior to standardization, and 48 patients poststandardization. Patients were predominantly male (70%); median age was 63; and median body mass index was 26. Standardization of postoperative care was associated with a decrease in median time to beginning both clear liquids and a postgastrectomy diet, earlier removal of epidural catheters, earlier use of oral pain medication, less time receiving intravenous fluids, and decreased length of stay (all P < .01). Groups showed no differences in complication rates, complication severity, diet intolerance, return to our Urgent Care Center, or readmission. Institution of standardized postoperative orders for total gastrectomy was associated with a significantly decreased length of stay and earlier oral feeding without increasing postoperative complications, early postoperative outpatient visits, or readmissions. Copyright © 2016 Elsevier Inc. All rights reserved.

On precipitation monitoring with theoretical statistical distributions

NASA Astrophysics Data System (ADS)

Cindrić, Ksenija; Juras, Josip; Pasarić, Zoran

2018-04-01

A common practice in meteorological drought monitoring is to transform the observed precipitation amounts to the standardised precipitation index (SPI). Though the gamma distribution is usually employed for this purpose, some other distribution may be used, particularly in regions where zero precipitation amounts are recorded frequently. In this study, two distributions are considered alongside with the gamma distribution: the compound Poisson exponential distribution (CPE) and the square root normal distribution (SRN). They are fitted to monthly precipitation amounts measured at 24 stations in Croatia in the 55-year-long period (1961-2015). At five stations, long-term series (1901-2015) are available and they have been used for a more detailed investigation. The accommodation of the theoretical distributions to empirical ones is tested by comparison of the corresponding empirical and theoretical ratios of the skewness and the coefficient of variation. Furthermore, following the common approach to precipitation monitoring (CLIMAT reports), the comparison of the empirical and theoretical quintiles in the two periods (1961-1990 and 1991-2015) is examined. The results from the present study reveal that it would be more appropriate to implement theoretical distributions in such climate reports, since they provide better evaluation for monitoring purposes than the current empirical distribution. Nevertheless, deciding on an optimal theoretical distribution for different climate regimes and for different time periods is not easy to accomplish. With regard to Croatian stations (covering different climate regimes), the CPE or SRN distribution could also be the right choice in the climatological practice, in addition to the gamma distribution.

A Theoretical Study on Seasonality

PubMed Central

Schmal, Christoph; Myung, Jihwan; Herzel, Hanspeter; Bordyugov, Grigory

2015-01-01

In addition to being endogenous, a circadian system must be able to communicate with the outside world and align its rhythmicity to the environment. As a result of such alignment, external Zeitgebers can entrain the circadian system. Entrainment expresses itself in coinciding periods of the circadian oscillator and the Zeitgeber and a stationary phase difference between them. The range of period mismatches between the circadian system and the Zeitgeber that Zeitgeber can overcome to entrain the oscillator is called an entrainment range. The width of the entrainment range usually increases with increasing Zeitgeber strength, resulting in a wedge-like Arnold tongue. This classical view of entrainment does not account for the effects of photoperiod on entrainment. Zeitgebers with extremely small or large photoperiods are intuitively closer to constant environments than equinoctial Zeitgebers and hence are expected to produce a narrower entrainment range. In this paper, we present theoretical results on entrainment under different photoperiods. We find that in the photoperiod-detuning parameter plane, the entrainment zone is shaped in the form of a skewed onion. The bottom and upper points of the onion are given by the free-running periods in DD and LL, respectively. The widest entrainment range is found near photoperiods of 50%. Within the onion, we calculated the entrainment phase that varies over a range of 12 h. The results of our theoretical study explain the experimentally observed behavior of the entrainment phase in dependence on the photoperiod. PMID:25999912

Theoretical Coalescence: A Method to Develop Qualitative Theory

PubMed Central

Morse, Janice M.

2018-01-01

Background Qualitative research is frequently context bound, lacks generalizability, and is limited in scope. Objectives The purpose of this article was to describe a method, theoretical coalescence, that provides a strategy for analyzing complex, high-level concepts and for developing generalizable theory. Theoretical coalescence is a method of theoretical expansion, inductive inquiry, of theory development, that uses data (rather than themes, categories, and published extracts of data) as the primary source for analysis. Here, using the development of the lay concept of enduring as an example, I explore the scientific development of the concept in multiple settings over many projects and link it within the Praxis Theory of Suffering. Methods As comprehension emerges when conducting theoretical coalescence, it is essential that raw data from various different situations be available for reinterpretation/reanalysis and comparison to identify the essential features of the concept. The concept is then reconstructed, with additional inquiry that builds description, and evidence is conducted and conceptualized to create a more expansive concept and theory. Results By utilizing apparently diverse data sets from different contexts that are linked by certain characteristics, the essential features of the concept emerge. Such inquiry is divergent and less bound by context yet purposeful, logical, and with significant pragmatic implications for practice in nursing and beyond our discipline. Conclusion Theoretical coalescence is a means by which qualitative inquiry is broadened to make an impact, to accommodate new theoretical shifts and concepts, and to make qualitative research applied and accessible in new ways. PMID:29360688

Hash Functions and Information Theoretic Security

NASA Astrophysics Data System (ADS)

Bagheri, Nasour; Knudsen, Lars R.; Naderi, Majid; Thomsen, Søren S.

Information theoretic security is an important security notion in cryptography as it provides a true lower bound for attack complexities. However, in practice attacks often have a higher cost than the information theoretic bound. In this paper we study the relationship between information theoretic attack costs and real costs. We show that in the information theoretic model, many well-known and commonly used hash functions such as MD5 and SHA-256 fail to be preimage resistant.

The evaluation of clinical and cost outcomes associated with earlier initiation of insulin in patients with type 2 diabetes mellitus.

PubMed

Smolen, Harry J; Murphy, Daniel R; Gahn, James C; Yu, Xueting; Curtis, Bradley H

2014-09-01

The treatment for patients with type 2 diabetes mellitus (T2DM) follows a stepwise progression. As a treatment loses its effectiveness, it is typically replaced with a more complex and frequently more costly treatment. Eventually this progression leads to the use of basal insulin typically with concomitant treatments (e.g., metformin, a GLP-1 RA [glucagon-like peptide-1 receptor agonist], a TZD [thiazolidinedione] or a DPP-4i [dipeptidyl peptidase 4 inhibitor]) and, ultimately, to basal-bolus insulin in some forms. As the cost of oral antidiabetics (OADs) and noninsulin injectables have approached, and in some cases exceeded, the cost of insulin, we reexamined the placement of insulin in T2DM treatment progression. Our hypothesis was that earlier use of insulin produces clinical and cost benefits due to its superior efficacy and treatment scalability at an acceptable cost when considered over a 5-year period. To (a) estimate clinical and payer cost outcomes of initiating insulin treatment for patients with T2DM earlier in their treatment progression and (b) estimate clinical and payer cost outcomes resulting from delays in escalating treatment for T2DM when indicated by patient hemoglobin A1c levels. We developed a Monte Carlo microsimulation model to estimate patients reaching target A1c, diabetes-related complications, mortality, and associated costs under various treatment strategies for newly diagnosed patients with T2DM. Treatment efficacies were modeled from results of randomized clinical trials, including the time and rate of A1c drift. A typical treatment progression was selected based on the American Diabetes Association and the European Association for the Study of Diabetes guidelines as the standard of care (SOC). Two treatment approaches were evaluated: two-stage insulin (basal plus antidiabetics followed by biphasic plus metformin) and single-stage insulin (biphasic plus metformin). For each approach, we analyzed multiple strategies. For each analysis

Mass Media and Socialization: Theoretic Approaches.

ERIC Educational Resources Information Center

Gordon, Thomas F.

This paper examines the major theoretical approaches to the study of socialization, with an emphasis on media effects. The three major bodies of literature studied are the major theoretic approaches utilized in the general area of developmental psychology, the theoretical paradigms evident in studies dealing more specifically with child…

Earlier detection of breast cancer by surveillance of women at familial risk.

PubMed

Tilanus-Linthorst, M M; Bartels, C C; Obdeijn, A I; Oudkerk, M

2000-03-01

A positive family history increases the risk for breast cancer which oft en occurs at a much younger age than in the general population. We stud ied whether surveillance of these women resulted in the detection of bre ast cancer in an earlier stage than in symptomatic patients with a famil y history. Between January 1994 and April 1998, 294 women with 15-25% r isk (moderate), mean age:43.3 (22-75) years, were screened with a yearly physical examination and mammography from 5 years before the youngest ag e of onset in the family and 384 women with >25% risk (high) for breast cancer, mean age: 42.9 (20-74) years were screened with a physical examination every 6 months and yearly mammography. From September 1995 breast magnetic resonance imaging (MRI) was also carried out for 109 high risk women where mammography showed over 50% density. 26 breast cancers detected under surveillance were significantly more often found in an early T1N0 stage than the 24 breast cancers in patients with a family history referred in that period because of symptoms: 81 versus 46% (P=0.018). Patients under surveillance were also less frequently node-positive than the symptomatic group: 19 versus 42% (P=0.12). 20 patients with a family history referred by our national screening programme in that period had 21 breast cancers detected, 81% in stage T1N0 and 5% node-positive, which was comparable to the results in our national screening programme T1N0 66%, N+ 24% resulting in a 30% reduction in mortality. The incidence in women under surveillance was 10.1 per 1000 in the 'high' risk group and 13.3 per 1000 in the 'moderate' risk group. Expected incidence in an average risk population aged 40-50 years is 1.5, expected if the group consisted of only gene carriers 15 per 1000. 23% of the breast cancers in the surveillance group were detected at physical examination, but occult at mammography. 38% were detected at mammography and clinically occult. Breast MRI (in the subgroup) detected 3 occult

Accessing Real-Life Episodic Information from Minutes versus Hours Earlier Modulates Hippocampal and High-Order Cortical Dynamics

PubMed Central

Chen, J.; Honey, C. J.; Simony, E.; Arcaro, M. J.; Norman, K. A.; Hasson, U.

2016-01-01

It is well known that formation of new episodic memories depends on hippocampus, but in real-life settings (e.g., conversation), hippocampal amnesics can utilize information from several minutes earlier. What neural systems outside hippocampus might support this minutes-long retention? In this study, subjects viewed an audiovisual movie continuously for 25 min; another group viewed the movie in 2 parts separated by a 1-day delay. Understanding Part 2 depended on retrieving information from Part 1, and thus hippocampus was required in the day-delay condition. But is hippocampus equally recruited to access the same information from minutes earlier? We show that accessing memories from a few minutes prior elicited less interaction between hippocampus and default mode network (DMN) cortical regions than accessing day-old memories of identical events, suggesting that recent information was available with less reliance on hippocampal retrieval. Moreover, the 2 groups evinced reliable but distinct DMN activity timecourses, reflecting differences in information carried in these regions when Part 1 was recent versus distant. The timecourses converged after 4 min, suggesting a time frame over which the continuous-viewing group may have relied less on hippocampal retrieval. We propose that cortical default mode regions can intrinsically retain real-life episodic information for several minutes. PMID:26240179

Final Report. Research in Theoretical High Energy Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greensite, Jeffrey P.; Golterman, Maarten F.L.

Grant-supported research in theoretical high-energy physics, conducted in the period 1992-2015 is briefly described, and a full listing of published articles result from those research activities is supplied.

Actual and apparent elitism in the environmental-conservation movement: analysis through a theoretical model of political participation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohai, P.

1983-01-01

Studies conducted since the late 1960's dealing with the nature of environmental concern and activism in the environmental movement have tended to be of two types: (a) analyses of the membership composition of voluntary environmental organizations and (b) analyses of survey data of various types and scope. Although the results of these studies have invariably been ambiguous and conflicting, a number of these studies have been consistently cited to support the assertion that environmental values are predominantly upper-middle class values and that the environmental movement is an elitist, upper-middle class movement. A review of these core studies reveals significant weaknessesmore » in the data used and in the data analyses, which appear to make the results of these studies tenuous at best. In this study, weaknesses of the earlier core studies are examined. The conclusion of environmental elitism is then challenged by making a distinction between those who are environmentally concerned and those who are politically active in environmental issues. This distinction is explained through a theoretical model of political participation, which is constructed from a unique integration of traditional social psychological and resource mobilization perspectives. Use of the model makes it possible to predict and account for the likelihood of individuals becoming politically active and provides a framework for testing whether conservation-environmental concern is related to socio-economic status.« less

Early full weight-bearing versus 6-week partial weight-bearing after open wedge high tibial osteotomy leads to earlier improvement of the clinical results: a prospective, randomised evaluation.

PubMed

Schröter, S; Ateschrang, A; Löwe, W; Nakayama, H; Stöckle, U; Ihle, C

2017-01-01

Open wedge high tibial osteotomy is a widespread treatment option in patients with varus malalignment and medial compartment osteoarthritis. There is no standardised protocol for post-operative rehabilitation available. The purpose of this study was to compare two post-operative rehabilitation protocols and to evaluate the clinical outcome of early full weight-bearing after open wedge HTO. One hundred and twenty consecutive patients with varus malalignment and medial compartment osteoarthritis received an open wedge HTO using an angular locking plate fixation between December 2008 and December 2011. All patients were assigned randomly into one of two groups with different post-operative rehabilitation protocols (11-day vs. 6-week 20-kg partial weight-bearing). Clinical outcome was evaluated using established instruments (Lequesne, Lysholm, HSS and IKDC scores) preoperatively, 6, 12 and 18 months post-operatively. Deformity analysis was performed preoperatively and during follow-up. All clinical scores showed a significant pre- to post-operative improvement. After 6 months, there was a higher improvement in the group of early full weight-bearing. The difference between preoperative and 6-month follow-up for the group with early full weight-bearing and for the group with 20-kg PWB for 6 weeks was 28 ± 26 and 18 ± 22, respectively, for the Lysholm score and -5.0 ± 5.1 and -3.0 ± 3.6, respectively, for the Lequesne score. Early full weight-bearing (11-day 20-kg partial weight-bearing) after open wedge HTO without bone graft leads to earlier improvement of the clinical results and can be recommended for post-operative rehabilitation after open wedge HTO and fixation with an angular locking plate. Therapeutic study, Level I.

Theoretical Perspectives Guiding QOL Indicator Projects

ERIC Educational Resources Information Center

Sirgy, M. Joseph

2011-01-01

Most of the theoretically based QOL indicators projects can be classified in terms of six major theoretical concepts: (a) socio-economic development (b) personal utility, (c) just society, (d) human development, (e) sustainability, and (f) functioning. I explain the core aspects of these six theoretical paradigms and show how they help guide QOL…

Selection for Earlier Flowering Crop Associated with Climatic Variations in the Sahel

PubMed Central

Vigouroux, Yves; Mariac, Cédric; De Mita, Stéphane; Pham, Jean-Louis; Gérard, Bruno; Kapran, Issoufou; Sagnard, Fabrice; Deu, Monique; Chantereau, Jacques; Ali, Abdou; Ndjeunga, Jupiter; Luong, Viviane; Thuillet, Anne-Céline; Saïdou, Abdoul-Aziz; Bezançon, Gilles

2011-01-01

Climate changes will have an impact on food production and will require costly adaptive responses. Adapting to a changing environment will be particularly challenging in sub-Saharan Africa where climate change is expected to have a major impact. However, one important phenomenon that is often overlooked and is poorly documented is the ability of agro-systems to rapidly adapt to environmental variations. Such an adaptation could proceed by the adoption of new varieties or by the adaptation of varieties to a changing environment. In this study, we analyzed these two processes in one of the driest agro-ecosystems in Africa, the Sahel. We performed a detailed study in Niger where pearl millet is the main crop and covers 65% of the cultivated area. To assess how the agro-system is responding to recent recurrent drought, we analyzed samples of pearl millet landraces collected in the same villages in 1976 and 2003 throughout the entire cultivated area of Niger. We studied phenological and morphological differences in the 1976 and 2003 collections by comparing them over three cropping seasons in a common garden experiment. We found no major changes in the main cultivated varieties or in their genetic diversity. However, we observed a significant shift in adaptive traits. Compared to the 1976 samples, samples collected in 2003 displayed a shorter lifecycle, and a reduction in plant and spike size. We also found that an early flowering allele at the PHYC locus increased in frequency between 1976 and 2003. The increase exceeded the effect of drift and sampling, suggesting a direct effect of selection for earliness on this gene. We conclude that recurrent drought can lead to selection for earlier flowering in a major Sahelian crop. Surprisingly, these results suggest that diffusion of crop varieties is not the main driver of short term adaptation to climatic variation. PMID:21573243

A Theory of Utility Conditionals: Paralogical Reasoning from Decision-Theoretic Leakage

ERIC Educational Resources Information Center

Bonnefon, Jean-Francois

2009-01-01

Many "if p, then q" conditionals have decision-theoretic features, such as antecedents or consequents that relate to the utility functions of various agents. These decision-theoretic features leak into reasoning processes, resulting in various paralogical conclusions. The theory of utility conditionals offers a unified account of the various forms…

Deformation behavior of coherently strained InAs/GaAs(111)A heteroepitaxial systems: Theoretical calculations and experimental measurements

NASA Astrophysics Data System (ADS)

Zepeda-Ruiz, Luis A.; Pelzel, Rodney I.; Nosho, Brett Z.; Weinberg, W. Henry; Maroudas, Dimitrios

2001-09-01

A comprehensive, quantitative analysis is presented of the deformation behavior of coherently strained InAs/GaAs(111)A heteroepitaxial systems. The analysis combines a hierarchical theoretical approach with experimental measurements. Continuum linear elasticity theory is linked with atomic-scale calculations of structural relaxation for detailed theoretical studies of deformation in systems consisting of InAs thin films on thin GaAs(111)A substrates that are mechanically unconstrained at their bases. Molecular-beam epitaxy is used to grow very thin InAs films on both thick and thin GaAs buffer layers on epi-ready GaAs(111)A substrates. The deformation state of these samples is characterized by x-ray diffraction (XRD). The interplanar distances of thin GaAs buffer layers along the [220] and [111] crystallographic directions obtained from the corresponding XRD spectra indicate clearly that thin buffer layers deform parallel to the InAs/GaAs(111)A interfacial plane, thus aiding in the accommodation of the strain induced by lattice mismatch. The experimental measurements are in excellent agreement with the calculated lattice interplanar distances and the corresponding strain fields in the thin mechanically unconstrained substrates considered in the theoretical analysis. Therefore, this work contributes direct evidence in support of our earlier proposal that thin buffer layers in layer-by-layer semiconductor heteroepitaxy exhibit mechanical behavior similar to that of compliant substrates [see, e.g., B. Z. Nosho, L. A. Zepeda-Ruiz, R. I. Pelzel, W. H. Weinberg, and D. Maroudas, Appl. Phys. Lett. 75, 829 (1999)].

Earlier and greater hand pre-shaping in the elderly: a study based on kinematic analysis of reaching movements to grasp objects.

PubMed

Tamaru, Yoshiki; Naito, Yasuo; Nishikawa, Takashi

2017-11-01

Elderly people are less able to manipulate objects skilfully than young adults. Although previous studies have examined age-related deterioration of hand movements with a focus on the phase after grasping objects, the changes in the reaching phase have not been studied thus far. We aimed to examine whether changes in hand shape patterns during the reaching phase of grasping movements differ between young adults and the elderly. Ten healthy elderly adults and 10 healthy young adults were examined using the Simple Test for Evaluating Hand Functions and kinetic analysis of hand pre-shaping reach-to-grasp tasks. The results were then compared between the two groups. For kinetic analysis, we measured the time of peak tangential velocity of the wrist and the inter-fingertip distance (the distance between the tips of the thumb and index finger) at different time points. The results showed that the elderly group's performance on the Simple Test for Evaluating Hand Functions was significantly lower than that of the young adult group, irrespective of whether the dominant or non-dominant hand was used, indicating deterioration of hand movement in the elderly. The peak tangential velocity of the wrist in either hand appeared significantly earlier in the elderly group than in the young adult group. The elderly group also showed larger inter-fingertip distances with arch-like fingertip trajectories compared to the young adult group for all object sizes. To perform accurate prehension, elderly people have an earlier peak tangential velocity point than young adults. This allows for a longer adjustment time for reaching and grasping movements and for reducing errors in object prehension by opening the hand and fingers wider. Elderly individuals gradually modify their strategy based on previous successes and failures during daily living to compensate for their decline in dexterity and operational capabilities. © 2017 Japanese Psychogeriatric Society.

Quadruple cancer including Bowen's disease after arsenic injections 40 years earlier: report of a case.

PubMed

Murata, K; Iwazawa, T; Takayama, T; Yamashita, K; Okagawa, K

1994-01-01

This report describes the successful treatment of quadruple cancer including Bowen's disease in a 71-year-old man who had been given injections of salvarsan, an arsenic compound, for syphilis more than 40 years earlier. Resection of a skin lesion on his chest subsequently confirmed a diagnosis of Bowen's disease, 3 years after which he was operated on for concurrent gastric cancer and sigmoid colon cancer. A fourth cancer was discovered on his left vocal cord 2 weeks after this operation; it was resected 2 years later. A discussion of multiple malignant neoplasms and the possible relationship between arsenic and cancer is presented following this case report.

Theoretical Overview on the Improvement of Interest in Learning Theoretical Course for Engineering Students

ERIC Educational Resources Information Center

Xiao, Manlin; Zhang, Jianglin

2016-01-01

The phenomenon that engineering students have little interest in theoretical knowledge learning is more and more apparent. Therefore, most students fail to understand and apply theories to solve practical problems. To solve this problem, the importance of improving students' interest in the learning theoretical course is discussed firstly in this…

Recombination in liquid filled ionisation chambers with multiple charge carrier species: Theoretical and numerical results

NASA Astrophysics Data System (ADS)

Aguiar, P.; González-Castaño, D. M.; Gómez, F.; Pardo-Montero, J.

2014-10-01

Liquid-filled ionisation chambers (LICs) are used in radiotherapy for dosimetry and quality assurance. Volume recombination can be quite important in LICs for moderate dose rates, causing non-linearities in the dose rate response of these detectors, and needs to be corrected for. This effect is usually described with Greening and Boag models for continuous and pulsed radiation respectively. Such models assume that the charge is carried by two different species, positive and negative ions, each of those species with a given mobility. However, LICs operating in non-ultrapure mode can contain different types of electronegative impurities with different mobilities, thus increasing the number of different charge carriers. If this is the case, Greening and Boag models can be no longer valid and need to be reformulated. In this work we present a theoretical and numerical study of volume recombination in parallel-plate LICs with multiple charge carrier species, extending Boag and Greening models. Results from a recent publication that reported three different mobilities in an isooctane-filled LIC have been used to study the effect of extra carrier species on recombination. We have found that in pulsed beams the inclusion of extra mobilities does not affect volume recombination much, a behaviour that was expected because Boag formula for charge collection efficiency does not depend on the mobilities of the charge carriers if the Debye relationship between mobilities and recombination constant holds. This is not the case in continuous radiation, where the presence of extra charge carrier species significantly affects the amount of volume recombination.

Earlier Endpoints Are Required for Hemorrhagic Shock Trials among Severely Injured Patients

PubMed Central

Fox, Erin E.; Holcomb, John B.; Wade, Charles E.; Bulger, Eileen M.; Tilley, Barbara C.

2016-01-01

Background Choosing the appropriate endpoint for a trauma hemorrhage control trial can determine the likelihood of its success. Recent Phase 3 trials and observational studies have used 24-hour and/or 30-day all-cause mortality as the primary endpoint and some have not used exception from informed consent (EFIC), resulting in multiple failed trials. Five recent high-quality prospective studies among 4,064 hemorrhaging trauma patients provide new evidence to support earlier primary endpoints. Methods The goal of this project was to determine the optimal endpoint for hemorrhage control trials using existing literature and new analyses of previously published data. Results Recent studies among bleeding trauma patients show that hemorrhagic deaths occur rapidly, at a high rate, and in a consistent pattern. Early preventable deaths among trauma patients are largely due to hemorrhage and the median time to hemorrhagic death from admission is 2.0-2.6 hours. Approximately 85% of hemorrhagic deaths occur within 6 hours. The hourly mortality rate due to traumatic injury decreases rapidly after enrollment from 4.6% per hour at 1 hour post-enrollment to 1% per hour at 6 hours to <0.1% per hour by 9 hours and thereafter. Early primary endpoints (within 6 hours) have critically important benefits for hemorrhage control trials, including being congruent with the median time to hemorrhagic death, biologic plausibility, and enabling the use of all-cause mortality, which is definitive and objective. Conclusions Primary endpoints should be congruent with the timing of the disease process. Therefore, if a resuscitation/hemorrhage control intervention is under study, a primary endpoint of all-cause mortality evaluated within the first 6 hours is appropriate. Before choosing the timing of the primary endpoint for a large multicenter trial, we recommend performing a Phase 2 trial under EFIC to better understand the effects of the hemorrhage control intervention and distribution of time

Theoretical study of thorium monoxide for the electron electric dipole moment search: electronic properties of H(3)Δ(1) in ThO.

PubMed

Skripnikov, L V; Titov, A V

2015-01-14

Recently, improved limits on the electron electric dipole moment, and dimensionless constant, kT,P, characterizing the strength of the T,P-odd pseudoscalar-scalar electron-nucleus neutral current interaction in the H(3)Δ1 state of ThO molecule were obtained by the ACME collaboration [J. Baron et al., Science 343, 269 (2014)]. The interpretation of the experiment in terms of these fundamental quantities is based on the results of theoretical study of appropriate ThO characteristics, the effective electric field acting on electron, Eeff, and a parameter of the T,P-odd pseudoscalar-scalar interaction, WT,P, given in Skripnikov et al. [J. Chem. Phys. 139, 221103 (2013)] by St. Petersburg group. To reduce the uncertainties of the given limits, we report improved calculations of the molecular state-specific quantities Eeff, 81.5 GV/cm, and WT,P, 112 kHz, with the uncertainty within 7% of the magnitudes. Thus, the values recommended to use for the upper limits of the quantities are 75.8 GV/cm and 104 kHz, correspondingly. The hyperfine structure constant, molecule-frame dipole moment of the H(3)Δ1 state, and the H(3)Δ1 → X(1)Σ(+) transition energy which, in general, can serve as a measure of reliability of the obtained Eeff and WT,P values are also calculated. In addition, we report the first calculation of g-factor for the H(3)Δ1 state of ThO. The results are compared to the earlier experimental and theoretical studies, and a detailed analysis of uncertainties of the calculations is given.

M-Mode Ultrasound Reveals Earlier Gluteus Minimus Activity in Individuals With Chronic Hip Pain During a Step-down Task.

PubMed

Dieterich, Angela V; Deshon, Louise; Strauss, Geoffrey R; McKay, Jan; Pickard, Christine M

2016-04-01

Controlled laboratory study. The hip abductor muscles are important hip joint stabilizers. Hip joint pain may alter muscle recruitment. Motion-mode (M-mode) ultrasound enables noninvasive measurements of the onset of deep and superficial muscle motion, which is associated with activation onset. To compare (1) the onset of superficial and deep gluteus medius and gluteus minimus muscle motion relative to the instant of peak ground reaction force and (2) the level of swing-phase muscle motion during step-down between subjects with chronic hip pain and controls using M-mode ultrasound. Thirty-five subjects with anterior, nontraumatic hip pain for more than 6 months (mean ± SD age, 54 ± 9 years) and 35 controls (age, 57 ± 7 years) were scanned on the lateral hip of the leading leg during frontal step-down onto a force platform using M-mode ultrasound. Computerized motion detection with the Teager-Kaiser energy operator was applied on the gluteus minimus and the deep and superficial gluteus medius to determine the time lag between muscle motion onset and instant of peak ground reaction force and the level of gluteus minimus motion during the swing phase. Time lags and motion levels were averaged per subject, and t tests were used to determine between-group differences. In participants with hip pain, gluteus minimus motion onset was 103 milliseconds earlier (P = .002) and superficial gluteus medius motion was 70 milliseconds earlier (P = .047) than those in healthy control participants. The level of gluteus minimus swing-phase motion was higher with pain (P = .006). Increased gluteus minimus motion during the swing phase and earlier gluteus minimus and superficial gluteus medius motion in individuals with hip pain suggest an overall increase of muscle activity, possibly a protective behavior.

Medical Exercise Therapy for Treating Musculoskeletal Pain: A Narrative Review of Results from Randomized Controlled Trials with a Theoretical Perspective.

PubMed

Lorås, H; Østerås, B; Torstensen, T A; Østerås, H

2015-09-01

The purpose of this narrative review is to present an overview and theoretical rationale of medical exercise therapy (MET) as a physiotherapeutic rehabilitation treatment for musculoskeletal pain conditions. Results from randomized controlled trials (RCTs) conducted on MET are also presented. Computerized searches for any RCTs were conducted on the MET concept in the databases PubMed, Medline, Embase and ISI Web of science up to 2013. Overall findings from five included MET RCTs are long-term (≥1 year) reductions in pain and improved physical and functional capabilities. These results are interpreted in the context of the biopsychosocial model, advancing the view of a dynamic interaction among physiologic, psychological and social factors that influence pain modulation. MET is a biopsychosocial treatment that reduces pain and improves activities of daily living in patients with a musculoskeletal pain condition. Pain modulation is a key feature of MET, and an important area for further research is to elucidate the specific mechanisms behind the treatment effects. Copyright © 2015 John Wiley & Sons, Ltd.

Transcriptional analysis of micronutrient zinc-associated response for enhanced carbohydrate utilization and earlier solventogenesis in Clostridium acetobutylicum.

PubMed

Wu, You-Duo; Xue, Chuang; Chen, Li-Jie; Wan, Hui-Hui; Bai, Feng-Wu

2015-11-20

The micronutrient zinc plays vital roles in ABE fermentation by Clostridium acetobutylicum. In order to elucidate the zinc-associated response for enhanced glucose utilization and earlier solventogenesis, transcriptional analysis was performed on cells grown in glucose medium at the exponential growth phase of 16 h without/with supplementary zinc. Correspondingly, the gene glcG (CAC0570) encoding a glucose-specific PTS was significantly upregulated accompanied with the other two genes CAC1353 and CAC1354 for glucose transport in the presence of zinc. Additionally, genes involved in the metabolisms of six other carbohydrates (maltose, cellobiose, fructose, mannose, xylose and arabinose) were differentially expressed, indicating that the regulatory effect of micronutrient zinc is carbohydrate-specific with respects to the improved/inhibited carbohydrate utilization. More importantly, multiple genes responsible for glycolysis (glcK and pykA), acidogenesis (thlA, crt, etfA, etfB and bcd) and solventogenesis (ctfB and bdhA) of C. acetobutylicum prominently responded to the supplementary zinc at differential expression levels. Comparative analysis of intracellular metabolites revealed that the branch node intermediates such as acetyl-CoA, acetoacetyl-CoA, butyl-CoA, and reducing power NADH remained relatively lower whereas more ATP was generated due to enhanced glycolysis pathway and earlier initiation of solventogenesis, suggesting that the micronutrient zinc-associated response for the selected intracellular metabolisms is significantly pleiotropic.

Optical graphene quantum dots gas sensors: Theoretical study

NASA Astrophysics Data System (ADS)

Raeyani, D.; Shojaei, S.; Ahmadi-Kandjani, S.

2018-02-01

In this work, we theoretically studied the changes of graphene quantum dots (GQD) absorption spectra under the influence of different gases to indicate optical gas sensing features of GQDs. The adsorption of gas molecules such as CO2, N2 and Ar on GQDs have been theoretically investigated through time-dependent density functional theory (TDDFT) calculations. Our study revealed that UV-Vis absorption spectrum of GQDs in the presence of CO2 undergoes considerable changes than that of N2 and Ar. The shift of maximum absorption wavelength for adsorption of CO2, N2 and Ar in same distance from GQD in addition to density of state (DOS) and orbital analyses have been obtained. To verify our theoretical results, comparison with experimental study has been done and good agreement has been observed. Comparing with electrical property of GQD, optical properties showed an efficient tool to be implemented in gas adsorption and paves the way towards GQD optical gas sensors.

APIC: Absolute Position Interfero Coronagraph for direct exoplanet detection: first laboratory results

NASA Astrophysics Data System (ADS)

Allouche, Fatmé; Glindemann, Andreas; Aristidi, Eric; Vakili, Farrokh

2010-07-01

For the detection and direct imaging of exoplanets, when the intensity ratio between a star and its orbiting planet can largely exceed 106, coronagraphic methods are mandatory. In 1996, a concept of achromatic interferocoronagraph (AIC) was presented by J. Gay and Y. Rabbia for the detection of very faint stellar companions, such as exoplanets. In an earlier paper, we presented a modified version of the AIC permitting to determine the relative position of these faint companions with respect to the parent star, a problem unsolved in the original design of the AIC. Our modification lied in the use of cylindrical lens doublets as field rotator. By placing two of them in one arm of the interferometric set-up of AIC, we destroyed the axis of symmetry induced by the AIC's original design. Our theoretical study, along with the numerical computations, presented then, and the preliminary test bench results aiming at validating the cylindrical lens doublet field rotation capability, presented in this paper, show that the axis of symmetry is destroyed when one of the cylindrical doublets is rotated around the optic axis.

Estimation of refueling emissions based on theoretical model and effects of E10 fuel on refueling and evaporative emissions from gasoline cars.

PubMed

Yamada, Hiroyuki; Inomata, Satoshi; Tanimoto, Hiroshi; Hata, Hiroo; Tonokura, Kenichi

2018-05-01

The effects of Reid vapor pressure (RVP) on refueling emissions and the effects of ethanol 10% (E10) fuel on refueling and evaporative emissions were observed using six cars and seven fuels. The results indicated that refueling emissions can be reproduced by a simple theoretical model in which fuel vapor in the empty space in the tank is pushed out by the refueling process. In this model, the vapor pressures of fuels can be estimated by the Clausius-Clapeyron equation as a function of temperature. We also evaluated E10 fuel in terms of refueling and evaporative emissions, excluding the effect of contamination of ethanol in the canister. E10 fuel had no effect on the refueling emissions in cases without onboard refueling vapor recovery. E10 showed increased permeation emissions in evaporative emissions because of the high permeability of ethanol. And with E10 fuel, breakthrough emissions appeared earlier but broke through slower than normal fuel. Finally, canisters could store more fuel vapor with E10 fuel. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental and Theoretical Investigations of a Mechanical Lever System Driven by a DC Motor

NASA Astrophysics Data System (ADS)

Nana, B.; Fautso Kuiate, G.; Yamgoué, S. B.

This paper presents theoretical and experimental results on the investigation of the dynamics of a nonlinear electromechanical system made of a lever arm actuated by a DC motor and controlled through a repulsive magnetic force. We use the method of harmonic balance to derive oscillatory solutions. Theoretical tools such as, bifurcation diagrams, Lyapunov exponents, phase portraits, are used to unveil the rich nonlinear behavior of the system including chaos and hysteresis. The experimental results are in close accordance with the theoretical predictions.

Evolution of Theoretical Perspectives in My Research

NASA Astrophysics Data System (ADS)

Otero, Valerie K.

2009-11-01

Over the past 10 years I have been using socio-cultural theoretical perspectives to understand how people learn physics in a highly interactive, inquiry-based physics course such as Physics and Everyday Thinking [1]. As a result of using various perspectives (e.g. Distributed Cognition and Vygotsky's Theory of Concept Formation), my understanding of how these perspectives can be useful for investigating students' learning processes has changed. In this paper, I illustrate changes in my thinking about the role of socio-cultural perspectives in understanding physics learning and describe elements of my thinking that have remained fairly stable. Finally, I will discuss pitfalls in the use of certain perspectives and discuss areas that need attention in theoretical development for PER.

M dwarfs: Theoretical work

NASA Technical Reports Server (NTRS)

Mullan, Dermott J.

1987-01-01

Theoretical work on the atmospheres of M dwarfs has progressed along lines parallel to those followed in the study of other classes of stars. Such models have become increasingly sophisticated as improvements in opacities, in the equation of state, and in the treatment of convection were incorporated during the last 15 to 20 years. As a result, spectrophotometric data on M dwarfs can now be fitted rather well by current models. The various attempts at modeling M dwarf photospheres in purely thermal terms are summarized. Some extensions of these models to include the effects of microturbulence and magnetic inhomogeneities are presented.

Penetration with Long Rods: A Theoretical Framework and Comparison with Instrumented Impacts,

DTIC Science & Technology

1980-06-01

theoretical framework for an experimental program is described. The theory of one dimensional wave propagation is used to show how data from instrumented long rods and targets may be fitted together to give a...the theoretical framework . In the final section the results to date are discussed.

Cosmopolitanism: Extending Our Theoretical Framework for Transcultural Technical Communication Research and Teaching

ERIC Educational Resources Information Center

Palmer, Zsuzsanna Bacsa

2013-01-01

The effects of globalization on communication products and processes have resulted in document features and interactional practices that are sometimes difficult to describe within current theoretical frameworks of inter/transcultural technical communication. Although it has been recognized in our field that the old theoretical frameworks and…

Electron collisions with small esters: A joint experimental-theoretical investigation

NASA Astrophysics Data System (ADS)

de Souza, G. L. C.; da Silva, L. A.; de Sousa, W. J. C.; Sugohara, R. T.; Iga, I.; dos Santos, A. S.; Machado, L. E.; Homem, M. G. P.; Brescansin, L. M.; Lucchese, R. R.; Lee, M.-T.

2016-03-01

A theoretical and experimental investigation on elastic electron scattering by two small esters, namely, methyl formate and ethyl acetate, is reported. Experimental differential, integral, and momentum-transfer cross sections are given in the 30-1000 eV and 10∘-120∘ ranges. The relative-flow technique was used to determine such quantities. Particularly for methyl formate, a theoretical study was also carried out in the 1-500 eV range. A complex optical potential derived from a Hartree-Fock molecular wave function was used to represent the collision dynamics, whereas the Padé approximation was used to solve the scattering equations. In addition, calculations based on the framework of the independent-atom model (IAM) were also performed for both targets. In general, there is good agreement between our experimental data and the present theoretical results calculated using the Padé approximation. The theoretical results using the IAM also agree well with the experimental data at 200 eV and above. Moreover, for methyl formate, our calculations reveal a 2A'' (π*) resonance at about 3.0 eV and a σ*-type resonance centered at about 8.0 eV in the 2A' scattering channel. The π* resonance is also seen in other targets containing a carbonyl group.

Clinical Evidence for the Earlier Initiation of Insulin Therapy in Type 2 Diabetes

PubMed Central

2013-01-01

Abstract The natural history of type 2 diabetes mellitus (T2DM) is a relentless progression of β-cell failure and dysregulation of β-cell function with increasing metabolic derangement. Insulin remains the only glucose-lowering therapy that is efficacious throughout this continuum. However, the timing of introduction and the choice of insulin therapy remain contentious because of the heterogeneity of T2DM and the well-recognized behavioral and therapeutic challenges associated with this mode of therapy. Nevertheless, the early initiation of basal insulin has been shown to improve glycemic control and affect long-term outcomes in people with T2DM and is a treatment strategy supported by international guidelines as part of an individualized approach to chronic disease management. The rationale for early initiation of insulin is based on evidence demonstrating multifaceted benefits, including overcoming the glucotoxic effects of hyperglycemia, thereby facilitating “β-cell rest,” and preserving β-cell mass and function, while also improving insulin sensitivity. Independent of its effects on glycemic control, insulin possesses anti-inflammatory and antioxidant properties that may help protect against endothelial dysfunction and damage resulting in vascular disease. Insulin therapy and the achievement of good glycemic control earlier in T2DM provide long-term protection to end organs via “metabolic memory” regardless of subsequent treatments and degree of glycemic control. This is evidenced from long-term observations continuing from trials such as the United Kingdom Prospective Diabetes Study. As such, early initiation of insulin therapy may not only help to avoid the effects of prolonged glycemic burden, but may also positively alter the course of disease progression. PMID:23786228

A theoretical study of a laminar diffusion flame

NASA Technical Reports Server (NTRS)

Frair, K. L.

1978-01-01

Theoretical models of an axisymmetric laminar diffusion flame are discussed, with an emphasis on the behavior of such flames at increasing pressures. The flame-sheet or Burke-Schumann model (in terms of Bessel functions) and various boundary layer numerical solutions are presented and their results compared with experimental data. The most promising theoretical model combines the numerical flow field solution of the Patankar-Spalding computer code with the Pratt-Wormeck chemical reaction subroutine. The flame shapes for pressures of 1, 5, 10, 20, and 50 atmospheres were computed and agree remarkably well with experimental data. There is a noticeable shape change with pressure, believed to be a result of buoyancy effects. The chemical concentration profiles do not exhibit much dependence on pressure, a reflection of the fact that only one chemical mechanism was utilized at all pressures.

Quantum-Theoretical Methods and Studies Relating to Properties of Materials

DTIC Science & Technology

1989-12-19

particularly sensitive to the behavior of the electron distribution close to the nuclei, which contributes only to E(l). Although the above results were...other condensed phases. So it was a useful test case to test the behavior of the theoretical computations for the gas phase relative to that in the...increasingly complicated and time- comsuming electron-correlation approximations should assure a small error in the theoret- ically computed enthalpy for a

Theoretical models of helicopter rotor noise

NASA Technical Reports Server (NTRS)

Hawkings, D. L.

1978-01-01

For low speed rotors, it is shown that unsteady load models are only partially successful in predicting experimental levels. A theoretical model is presented which leads to the concept of unsteady thickness noise. This gives better agreement with test results. For high speed rotors, it is argued that present models are incomplete and that other mechanisms are at work. Some possibilities are briefly discussed.

Attachment styles, earlier interpersonal relationships and schizotypy in a non-clinical sample.

PubMed

Berry, Katherine; Band, Rebecca; Corcoran, Rhiannon; Barrowclough, Christine; Wearden, Alison

2007-12-01

This paper investigates associations between adult attachment style, relationships with significant others during childhood, traumatic life-events and schizotypy. Relationships between attachment and hypothesized correlates were investigated in a cross-sectional design using an analogue sample. The reliability of the attachment and trauma measures was investigated using a test-retest design. Three hundred and four students completed the self-report version of the Psychosis Attachment Measure (PAM), maternal and paternal versions of the Parental Bonding Instrument, the Attachment History Questionnaire, a measure of trauma and the Oxford-Liverpool Inventory of Feelings and Experiences scale through an internet website. As predicted, there were statistically significant associations between insecure attachment in adult relationships and experiences of negative interpersonal events. Both earlier interpersonal experiences and adult attachment style predicted schizotypy, and adult attachment style emerged as an independent predictor of positive schizotypal characteristics. The findings support associations between adult attachment style and previous interpersonal experiences and between adult attachment and schizotypy. The PAM is a reliable and valid instrument that can be used to explore attachment styles in analogue samples and associations between attachment styles and psychotic symptoms in clinical samples.

Action of Molecular Switches in GPCRs - Theoretical and Experimental Studies

PubMed Central

Trzaskowski, B; Latek, D; Yuan, S; Ghoshdastider, U; Debinski, A; Filipek, S

2012-01-01

G protein coupled receptors (GPCRs), also called 7TM receptors, form a huge superfamily of membrane proteins that, upon activation by extracellular agonists, pass the signal to the cell interior. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. Biochemical and crystallographic methods together with molecular dynamics simulations and other theoretical techniques provided models of the receptor activation based on the action of so-called “molecular switches” buried in the receptor structure. They are changed by agonists but also by inverse agonists evoking an ensemble of activation states leading toward different activation pathways. Switches discovered so far include the ionic lock switch, the 3-7 lock switch, the tyrosine toggle switch linked with the nPxxy motif in TM7, and the transmission switch. The latter one was proposed instead of the tryptophan rotamer toggle switch because no change of the rotamer was observed in structures of activated receptors. The global toggle switch suggested earlier consisting of a vertical rigid motion of TM6, seems also to be implausible based on the recent crystal structures of GPCRs with agonists. Theoretical and experimental methods (crystallography, NMR, specific spectroscopic methods like FRET/BRET but also single-molecule-force-spectroscopy) are currently used to study the effect of ligands on the receptor structure, location of stable structural segments/domains of GPCRs, and to answer the still open question on how ligands are binding: either via ensemble of conformational receptor states or rather via induced fit mechanisms. On the other hand the structural investigations of homo- and heterodimers and higher oligomers revealed the mechanism of allosteric signal transmission and receptor

Action of molecular switches in GPCRs--theoretical and experimental studies.

PubMed

Trzaskowski, B; Latek, D; Yuan, S; Ghoshdastider, U; Debinski, A; Filipek, S

2012-01-01

G protein coupled receptors (GPCRs), also called 7TM receptors, form a huge superfamily of membrane proteins that, upon activation by extracellular agonists, pass the signal to the cell interior. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. Biochemical and crystallographic methods together with molecular dynamics simulations and other theoretical techniques provided models of the receptor activation based on the action of so-called "molecular switches" buried in the receptor structure. They are changed by agonists but also by inverse agonists evoking an ensemble of activation states leading toward different activation pathways. Switches discovered so far include the ionic lock switch, the 3-7 lock switch, the tyrosine toggle switch linked with the nPxxy motif in TM7, and the transmission switch. The latter one was proposed instead of the tryptophan rotamer toggle switch because no change of the rotamer was observed in structures of activated receptors. The global toggle switch suggested earlier consisting of a vertical rigid motion of TM6, seems also to be implausible based on the recent crystal structures of GPCRs with agonists. Theoretical and experimental methods (crystallography, NMR, specific spectroscopic methods like FRET/BRET but also single-molecule-force-spectroscopy) are currently used to study the effect of ligands on the receptor structure, location of stable structural segments/domains of GPCRs, and to answer the still open question on how ligands are binding: either via ensemble of conformational receptor states or rather via induced fit mechanisms. On the other hand the structural investigations of homoand heterodimers and higher oligomers revealed the mechanism of allosteric signal transmission and receptor

Documentation for the machine-readable version of A Finding List of Stars of Spectral Type F2 and Earlier in a North Galactic Pole Region

NASA Technical Reports Server (NTRS)

Warren, W. H., Jr.

1982-01-01

The machine-readable data set is the result of an objective-prism survey made with an 80 cm/120 cm Schmidt telescope. The F2 and earlier stars were isolated from later type objects by using the MK classification criteria. The catalog contains 601 stars and includes cross identifications to the BD and HD catalogs, coordinates, photographic magnitudes and spectral types. A separate file contains the remarks from the original data tables merged with those following the data. The machine-readable files are described.

Improper ferroelectricity: A theoretical and experimental investigation

NASA Astrophysics Data System (ADS)

Hardy, J. R.; Ullman, F. G.

1984-02-01

A combined theoretical and experimental study has been made of the origins and properties of the improper ferroelectricity associated with structural modulations of non-zero wavelengths. Two classes of materials have been studied: rare earth molybdates (specifically, gadolinium molybdate: GMO), and potassium selenate and its isomorphs. In the former, the modulation is produced by a zone boundary phonon instability, and in the latter by the instability of a phonon of wave vector approximately two-thirds of the way to the zone-boundary. In the second case the initial result is a modulated structure whose repeat distance is not a rational multiple of the basic lattice repeat distance. This result is a modulated polarization which, when the basic modulation locks in to a rational multiple of the lattice spacing, becomes uniform, and improper ferroelectricity results. The origins of these effects have been elucidated by theoretical studies, initially semi-empirical, but subsequently from first-principles. These complemented the experimental work, which primarily used inelastic light scattering, uniaxial stress, and hydrostatic pressure, to probe the balance between the interionic forces through the effects on the phonons and dielectric properties.

An experimental-theoretical study of free vibrations of plates on elastic point supports

NASA Technical Reports Server (NTRS)

Leuner, T. R.

1972-01-01

A theoretical and experimental study is made to investigate the effect on plate vibrations of varying the stiffness of corner elastic point supports. A theoretical model is developed using a Rayleigh-Ritz analysis which approximates the plate mode shapes as products of free-free beam modes. The elastic point supports are modelled both as massless translational springs, and springs with tip masses. The tip masses are included to better represent the experimental supports. An experiment is constructed using the bending stiffness of horizontal beams to support a square plate at its four corners. The stiffness of these supports can be varied over such a range that the plate fundamental frequency is lowered to 40% of the rigid support frequency. The variation with support stiffness of the frequencies of the first eight plate modes is measured, and compared with the theoretical results. The plate mode shapes for rigid supports are analyzed using holographic interferometry. There is excellent agreement between the theoretical and experimental results, except for high plate modes where the theoretical model is demonstrated to be inadequate.

Theoretical and experimental aspects of chaos control by time-delayed feedback.

PubMed

Just, Wolfram; Benner, Hartmut; Reibold, Ekkehard

2003-03-01

We review recent developments for the control of chaos by time-delayed feedback methods. While such methods are easily applied even in quite complex experimental context the theoretical analysis yields infinite-dimensional differential-difference systems which are hard to tackle. The essential ideas for a general theoretical approach are sketched and the results are compared to electronic circuits and to high power ferromagnetic resonance experiments. Our results show that the control performance can be understood on the basis of experimentally accessible quantities without resort to any model for the internal dynamics.

The power of theoretical knowledge.

PubMed

Alligood, Martha Raile

2011-10-01

Nursing theoretical knowledge has demonstrated powerful contributions to education, research, administration and professional practice for guiding nursing thought and action. That knowledge has shifted the primary focus of the nurse from nursing functions to the person. Theoretical views of the person raise new questions, create new approaches and instruments for nursing research, and expand nursing scholarship throughout the world.

Implementation Challenges and Results

ERIC Educational Resources Information Center

Walters, Kirk; Sorensen, Nicholas

2013-01-01

This paper describes the implementation of the online and f2f summer algebra courses that were delivered in summers 2011 and 2012. These data will be used to frame the impact results presented in an earlier paper. In particular, the paper will provide a detailed picture of how the online course was structured and the types of supports provided to…

Tube Bulge Process : Theoretical Analysis and Finite Element Simulations

NASA Astrophysics Data System (ADS)

Velasco, Raphael; Boudeau, Nathalie

2007-05-01

This paper is focused on the determination of mechanics characteristics for tubular materials, using tube bulge process. A comparative study is made between two different models: theoretical model and finite element analysis. The theoretical model is completely developed, based first on a geometrical analysis of the tube profile during bulging, which is assumed to strain in arc of circles. Strain and stress analysis complete the theoretical model, which allows to evaluate tube thickness and state of stress, at any point of the free bulge region. Free bulging of a 304L stainless steel is simulated using Ls-Dyna 970. To validate FE simulations approach, a comparison between theoretical and finite elements models is led on several parameters such as: thickness variation at the free bulge region pole with bulge height, tube thickness variation with z axial coordinate, and von Mises stress variation with plastic strain. Finally, the influence of geometrical parameters deviations on flow stress curve is observed using analytical model: deviations of the tube outer diameter, its initial thickness and the bulge height measurement are taken into account to obtain a resulting error on plastic strain and von Mises stress.

Screening for Colorectal Cancer in African Americans: Determinants and Rationale for an Earlier Age to Commence Screening

PubMed Central

Carethers, John M.

2014-01-01

Colorectal cancer (CRC) screening is a highly cost-effective approach to reduce morbidity and mortality of patients, as well as reduce the prevalence of CRC in populations. Current recommendations for CRC screening for the asymptomatic general population begin at age 50 years, an age after which ~95% of cancers occur. Determinants that modify the timing and frequency for screening include a personal or family history of adenomatous polyps or CRC, the age of onset of these colonic lesions, and the presence or potential for a patient to harbor a higher-risk syndrome such as inflammatory bowel disease (IBD), familial adenomatous polyposis (FAP), or Lynch syndrome.. Although race, like family history, is a heritable factor, it has not engendered inclusion in the same broad systematic screening recommendations despite multiple studies demonstrating a disparity in the incidence and mortality from CRC, and the potential for targeted screening to reduce the disparity. In particular, African Americans, when compared to Caucasians, (a) have lower CRC screening utilization rates, (b) have an earlier presentation of CRC (0-8 years younger than Caucasians) and, more often have aggressive biological features more prone to metastasis, (c) have a higher CRC prevalence at all ages and a higher proportion of CRCs before 50 years of age (~11% vs 5% in Caucasians), (d) are less likely to know or transmit personal or family history of adenomas or CRC that might change their screening to an earlier age, (e) present with 7-15% excess right-sided CRCs that are not microsatellite unstable, (f) show higher frequencies of high-risk adenomas at every decile of age, and an excess of high-risk proximal adenomas that mirror the excess of proximal CRCs, (g) have cancers that demonstrate lower proportions of good prognostic biomarkers such as MSI and higher proportions of bad prognosticators such as EMAST, (h) may possess gut microbiota more conducive to initiating and/or propagating colonic

Digital Sound Encryption with Logistic Map and Number Theoretic Transform

NASA Astrophysics Data System (ADS)

Satria, Yudi; Gabe Rizky, P. H.; Suryadi, MT

2018-03-01

Digital sound security has limits on encrypting in Frequency Domain. Number Theoretic Transform based on field (GF 2521 – 1) improve and solve that problem. The algorithm for this sound encryption is based on combination of Chaos function and Number Theoretic Transform. The Chaos function that used in this paper is Logistic Map. The trials and the simulations are conducted by using 5 different digital sound files data tester in Wave File Extension Format and simulated at least 100 times each. The key stream resulted is random with verified by 15 NIST’s randomness test. The key space formed is very big which more than 10469. The processing speed of algorithm for encryption is slightly affected by Number Theoretic Transform.

Use of theoretical and conceptual frameworks in qualitative research.

PubMed

Green, Helen Elise

2014-07-01

To debate the definition and use of theoretical and conceptual frameworks in qualitative research. There is a paucity of literature to help the novice researcher to understand what theoretical and conceptual frameworks are and how they should be used. This paper acknowledges the interchangeable usage of these terms and researchers' confusion about the differences between the two. It discusses how researchers have used theoretical and conceptual frameworks and the notion of conceptual models. Detail is given about how one researcher incorporated a conceptual framework throughout a research project, the purpose for doing so and how this led to a resultant conceptual model. Concepts from Abbott (1988) and Witz ( 1992 ) were used to provide a framework for research involving two case study sites. The framework was used to determine research questions and give direction to interviews and discussions to focus the research. Some research methods do not overtly use a theoretical framework or conceptual framework in their design, but this is implicit and underpins the method design, for example in grounded theory. Other qualitative methods use one or the other to frame the design of a research project or to explain the outcomes. An example is given of how a conceptual framework was used throughout a research project. Theoretical and conceptual frameworks are terms that are regularly used in research but rarely explained. Textbooks should discuss what they are and how they can be used, so novice researchers understand how they can help with research design. Theoretical and conceptual frameworks need to be more clearly understood by researchers and correct terminology used to ensure clarity for novice researchers.

Comment on linewidths and shifts in the Stokes-Raman Q branch of D2 in He

NASA Technical Reports Server (NTRS)

Green, Sheldon; Blackmore, Robert; Monchick, Louis

1989-01-01

Collision-induced widths and shifts for Raman Q-branch transitions of D2 in He were calculated from S matrices obtained with converged close coupling scattering calculations on an accurate theoretical interaction potential. Results agree well with experimental values. Discrepancies between experimental line shifts and theoretical values from an earlier study (Blackmore et al., 1988) are traced to a computational error in that work. The effects of vibrational inelasticity and of centrifugal distortion on energy levels and on potential matrix elements, all of which were ignored in the earlier study, are explicitly considered here and found to be small.

von Neumann's Law: Theoretical and Microgravity Experimental Comparison for Coarsening Diffusion in Bubble Lattices

NASA Technical Reports Server (NTRS)

Noever, David A.

2000-01-01

The effects of gravity in influencing the theoretical limit for bubble lattice coarsening and aging behavior, otherwise called von Neumann's law, is examined theoretically and experimentally. Preliminary microgravity results will be discussed.

Theoretical investigation of gas-surface interactions

NASA Technical Reports Server (NTRS)

Lee, Timothy J.

1989-01-01

Four reprints are presented from four projects which are to be published in a refereed journal. Two are of interest to us and are presented herein. One is a description of a very detailed theoretical study of four anionic hydrogen bonded complexes. The other is a detailed study of the first generally reliable diagnostic for determining the quality of results that may be expected from single reference based electron correlation methods.

Does earlier arrival of the retrieval team improve short-term outcomes in outborn extremely premature infants?

PubMed

Sharpe, Janet B; Davies, Mark W

2018-05-31

The risk of mortality and morbidity is increased in outborn, extremely premature infants. We aim to determine whether earlier arrival of the retrieval team after the birth of infants less than 29 weeks gestation improves short-term mortality and morbidity. This is a retrospective analysis of a cohort of infants less than 29 weeks gestation who were retrieved to the Royal Brisbane and Women's Hospital (RBWH) over a 5-year period. Demographic information regarding the infant and mother, retrieval team arrival time and outcome data was collected. Primary outcomes investigated were mortality prior to discharge from hospital or a composite of mortality or severe intraventricular haemorrhage (IVH). Data on 105 infants were analysed; 88 infants (83.8%) survived to discharge home, and 79 (75.2%) survived to discharge without severe IVH. On univariate analysis, there was no significant association between age at arrival of the retrieval team and death prior to discharge (P = 0.94) or death prior to discharge or severe IVH (P = 0.83). On logistic regression analysis, age at arrival of retrieval team remained non-significant for a reduction in death prior to discharge and composite of death or severe IVH (P = 0.70 and P = 0.99, respectively). The earlier arrival of the retrieval team is not associated with improved short-term outcomes in outborn, extremely preterm infants who are retrieved and admitted to a tertiary neonatal intensive care unit - for infants where the retrieval team arrived within about 8 h of birth. © 2018 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

Double Helical Gear Performance Results in High Speed Gear Trains

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

2009-01-01

The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

Double Helical Gear Performance Results in High Speed Gear Trains

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

2010-01-01

The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

Unorthodox theoretical methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nedd, Sean

2012-01-01

The use of the ReaxFF force field to correlate with NMR mobilities of amine catalytic substituents on a mesoporous silica nanosphere surface is considered. The interfacing of the ReaxFF force field within the Surface Integrated Molecular Orbital/Molecular Mechanics (SIMOMM) method, in order to replicate earlier SIMOMM published data and to compare with the ReaxFF data, is discussed. The development of a new correlation consistent Composite Approach (ccCA) is presented, which incorporates the completely renormalized coupled cluster method with singles, doubles and non-iterative triples corrections towards the determination of heats of formations and reaction pathways which contain biradical species.

An inhibitor of polyamine synthesis arrests cells at an earlier stage of G1 than does calcium deprivation.

PubMed Central

Cheetham, B F

1983-01-01

Methylglyoxal bis(guanylhydrazone) completely inhibits the induction of thymidine kinase after serum stimulation of quiescent fibroblasts only if added within 3 h after serum, whereas calcium deprivation blocks this induction up to 12 h after serum stimulation. Experiments in which one of these blocks was imposed as the other was released confirmed that cells blocked by methylglyoxal bis(guanylhydrazone) are arrested at an earlier stage in G1 than cells blocked by calcium deprivation. PMID:6843551

Comparison of information theoretic divergences for sensor management

NASA Astrophysics Data System (ADS)

Yang, Chun; Kadar, Ivan; Blasch, Erik; Bakich, Michael

2011-06-01

In this paper, we compare the information-theoretic metrics of the Kullback-Leibler (K-L) and Renyi (α) divergence formulations for sensor management. Information-theoretic metrics have been well suited for sensor management as they afford comparisons between distributions resulting from different types of sensors under different actions. The difference in distributions can also be measured as entropy formulations to discern the communication channel capacity (i.e., Shannon limit). In this paper, we formulate a sensor management scenario for target tracking and compare various metrics for performance evaluation as a function of the design parameter (α) so as to determine which measures might be appropriate for sensor management given the dynamics of the scenario and design parameter.

Synthesis, structural characterization and comparison of experimental and theoretical results by DFT level of molecular structure of 4-(4-methoxyphenethyl)-3,5-dimethyl-4H-1,2,4-triazole.

PubMed

Düğdü, Esra; Ünver, Yasemin; Ünlüer, Dilek; Tanak, Hasan; Sancak, Kemal; Köysal, Yavuz; Işık, Şamil

2013-05-01

4-(4-Methoxyphenethyl)-3,5-dimethyl-4H-1,2,4-triazole (3) was synthesized from the reaction of ethyl N'-acetylacetohydrazonate (1) with 2-(4-methoxyphenyl)ethanamine (2). The structure of the title compound 3 has been inferred through IR, (1)H/(13)C NMR, mass spectrometry, elemental analyses and combination of X-ray crystallography and theoretical methods. In addition to the molecular geometry from X-ray determination, the molecular geometry and vibrational frequencies of the title compound 3 in the ground state, were calculated using the density functional method (B3LYP) with the 6-31G(d) basis set. The calculated results show that the optimized geometry can well reproduce the crystal structure and the theoretical vibrational frequencies show good agreement with experimental values. The nonlinear optical properties are also addressed theoretically. The predicted nonlinear optical properties of 3 are greater than ones of urea. In addition, DFT calculations of molecular electrostatic potentials and frontier molecular orbitals of the title compound were carried out at the B3LYP/6-31G(d) level of theory. Copyright © 2012. Published by Elsevier B.V.

Can social media data lead to earlier detection of drug-related adverse events?

PubMed

Duh, Mei Sheng; Cremieux, Pierre; Audenrode, Marc Van; Vekeman, Francis; Karner, Paul; Zhang, Haimin; Greenberg, Paul

2016-12-01

To compare the patient characteristics and the inter-temporal reporting patterns of adverse events (AEs) for atorvastatin (Lipitor ® ) and sibutramine (Meridia ® ) in social media (AskaPatient.com) versus the FDA Adverse Event Reporting System (FAERS). We identified clinically important AEs associated with atorvastatin (muscle pain) and sibutramine (cardiovascular AEs), compared their patterns in social media postings versus FAERS and used Granger causality tests to assess whether social media postings were useful in forecasting FAERS reports. We analyzed 998 and 270 social media postings between 2001 and 2014, 69 003 and 7383 FAERS reports between 1997 and 2014 for atorvastatin and sibutramine, respectively. Social media reporters were younger (atorvastatin: 53.9 vs. 64.0 years, p < 0.001; sibutramine: 36.8 vs. 43.8 years, p < 0.001). Social media reviews contained fewer serious AEs (atorvastatin, pain: 2.5% vs. 38.2%; sibutramine, cardiovascular issues: 7.9% vs. 63.0%; p < 0.001 for both) and concentrated on fewer types of AEs (proportion comprising the top 20 AEs: atorvastatin, 88.7% vs. 55.4%; sibutramine, 86.3% vs. 65.4%) compared with FAERS. While social media sibutramine reviews mentioning cardiac issues helped predict those in FAERS 11 months later (p < 0.001), social media atorvastatin reviews did not help predict FAERS reports. Social media AE reporters were younger and focused on less-serious and fewer types of AEs than FAERS reporters. The potential for social media to provide earlier indications of AEs compared with FAERS is uncertain. Our findings highlight some of the promises and limitations of online social media versus conventional pharmacovigilance sources and the need for careful interpretation of the results. © 2016 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd. © 2016 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.

Theoretical Developments in SUSY

NASA Astrophysics Data System (ADS)

Shifman, M.

2009-01-01

I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I will review theoretical developments of the recent years in non-perturbative supersymmetry.

Tuning of electronic band gaps and optoelectronic properties of binary strontium chalcogenides by means of doping of magnesium atom(s)- a first principles based theoretical initiative with mBJ, B3LYP and WC-GGA functionals

NASA Astrophysics Data System (ADS)

Debnath, Bimal; Sarkar, Utpal; Debbarma, Manish; Bhattacharjee, Rahul; Chattopadhyaya, Surya

2018-02-01

First principle based theoretical initiative is taken to tune the optoelectronic properties of binary strontium chalcogenide semiconductors by doping magnesium atom(s) into their rock-salt unit cells at specific concentrations x = 0.0, 0.25, 0.50, 0.75 and 1.0 and such tuning is established by studying structural, electronic and optical properties of designed binary compounds and ternary alloys employing WC-GGA, B3LYP and mBJ exchange-correlation functionals. Band structure of each compound is constructed and respective band gaps under all the potential schemes are measured. The band gap bowing and its microscopic origin are calculated using quadratic fit and Zunger's approach, respectively. The atomic and orbital origins of electronic states in the band structure of any compound are explored from its density of states. The nature of chemical bonds between the constituent atoms in each compound is explored from the valence electron density contour plots. Optical properties of any specimen are explored from the computed spectra of its dielectric function, refractive index, extinction coefficient, normal incidence reflectivity, optical conductivity optical absorption and energy loss function. Several calculated results are compared with available experimental and earlier theoretical data.

The characteristics of national health initiatives promoting earlier cancer diagnosis among adult populations: a systematic review protocol

PubMed Central

Calanzani, Natalia; Weller, David; Campbell, Christine

2017-01-01

Introduction The increasing burden of cancer morbidity and mortality has led to the development of national health initiatives to promote earlier cancer diagnosis and improve cancer survival. This protocol describes a systematic review aiming to identify the evidence about such initiatives among the adult population. We will describe their components, stakeholders and target populations, and summarise their outcomes. Methods and analysis We will search databases and websites for peer-reviewed publications and grey literature on national health initiatives in high-income countries as defined by the World Bank. Quantitative, qualitative and mixed-methods studies will be included and assessed for their methodological quality. Study selection, quality assessment and data extraction will be carried out independently by two reviewers. Narrative synthesis will be used to analyse the findings. Ethics and dissemination This systematic review analyses secondary data and ethical approval is not required. Review findings will be helpful to researchers, policy makers, governments and other key stakeholders developing similar initiatives and assessing cancer outcomes. The results will be submitted to a peer-reviewed journal in order to reach a diverse group of healthcare professionals, researchers and policy makers. This systematic review protocol is registered at PROSPERO (CRD42016047233). PMID:28698336

Presetting ECG electrodes for earlier heart rate detection in the delivery room.

PubMed

Gulati, Rashmi; Zayek, Michael; Eyal, Fabien

2018-07-01

To determine whether heart rate (HR) could be detected earlier than by pulse oximeter (POX), using a novel method of application of electrocardiogram (ECG) electrodes during neonatal resuscitation in the delivery room. ECG electrodes were set before delivery to be applied to the back of infants' thorax. Time to detect HR was recorded as soon as a numerical HR along with a recognizable and persistent QRS complex was observed on ECG monitor (HRECG) and a plethysmographic waveform was seen on POX monitor (HRPOX). Out of 334 infants, 49 were <31 weeks of gestational age. Overall, the median (interquartile range, IQR) time to detect HRECG was significantly shorter [29 (5, 60) seconds] than time by POX [60 (45,120) seconds], (p < 0.001). Similarly, in <31-week infants, the median (IQR) time to detect HRECG was 10 (2, 40) seconds compared to 60 (30,120) seconds by POX, (p < 0.001). Failure to have HR detected by 1 minute occurred in 30%, 54% and 20% of infants by ECG, POX and either of the devices, respectively. In the delivery room, electrodes applied by the study method are more effective than pulse oximetry in providing the neonatal team with timely HR information that is necessary for proper resuscitative actions. Published by Elsevier B.V.

Theoretical prediction of thick wing and pylon-fuselage-fanpod-nacelle aerodynamic characteristics at subcritical speeds. Part 1: Theory and results

NASA Technical Reports Server (NTRS)

Tulinius, J. R.

1974-01-01

The theoretical development and the comparison of results with data of a thick wing and pylon-fuselage-fanpod-nacelle analysis are presented. The analysis utilizes potential flow theory to compute the surface velocities and pressures, section lift and center of pressure, and the total configuration lift, moment, and vortex drag. The skin friction drag is also estimated in the analysis. The perturbation velocities induced by the wing and pylon, fuselage and fanpod, and nacelle are represented by source and vortex lattices, quadrilateral vortices, and source frustums, respectively. The strengths of these singularities are solved for simultaneously including all interference effects. The wing and pylon planforms, twists, cambers, and thickness distributions, and the fuselage and fanpod geometries can be arbitrary in shape, provided the surface gradients are smooth. The flow through nacelle is assumed to be axisymmetric. An axisymmetric center engine hub can also be included. The pylon and nacelle can be attached to the wing, fuselage, or fanpod.

An information-theoretical perspective on weighted ensemble forecasts

NASA Astrophysics Data System (ADS)

Weijs, Steven V.; van de Giesen, Nick

2013-08-01

This paper presents an information-theoretical method for weighting ensemble forecasts with new information. Weighted ensemble forecasts can be used to adjust the distribution that an existing ensemble of time series represents, without modifying the values in the ensemble itself. The weighting can, for example, add new seasonal forecast information in an existing ensemble of historically measured time series that represents climatic uncertainty. A recent article in this journal compared several methods to determine the weights for the ensemble members and introduced the pdf-ratio method. In this article, a new method, the minimum relative entropy update (MRE-update), is presented. Based on the principle of minimum discrimination information, an extension of the principle of maximum entropy (POME), the method ensures that no more information is added to the ensemble than is present in the forecast. This is achieved by minimizing relative entropy, with the forecast information imposed as constraints. From this same perspective, an information-theoretical view on the various weighting methods is presented. The MRE-update is compared with the existing methods and the parallels with the pdf-ratio method are analysed. The paper provides a new, information-theoretical justification for one version of the pdf-ratio method that turns out to be equivalent to the MRE-update. All other methods result in sets of ensemble weights that, seen from the information-theoretical perspective, add either too little or too much (i.e. fictitious) information to the ensemble.

Analysis of arrhythmic events is useful to detect lead failure earlier in patients followed by remote monitoring.

PubMed

Nishii, Nobuhiro; Miyoshi, Akihito; Kubo, Motoki; Miyamoto, Masakazu; Morimoto, Yoshimasa; Kawada, Satoshi; Nakagawa, Koji; Watanabe, Atsuyuki; Nakamura, Kazufumi; Morita, Hiroshi; Ito, Hiroshi

2018-03-01

Remote monitoring (RM) has been advocated as the new standard of care for patients with cardiovascular implantable electronic devices (CIEDs). RM has allowed the early detection of adverse clinical events, such as arrhythmia, lead failure, and battery depletion. However, lead failure was often identified only by arrhythmic events, but not impedance abnormalities. To compare the usefulness of arrhythmic events with conventional impedance abnormalities for identifying lead failure in CIED patients followed by RM. CIED patients in 12 hospitals have been followed by the RM center in Okayama University Hospital. All transmitted data have been analyzed and summarized. From April 2009 to March 2016, 1,873 patients have been followed by the RM center. During the mean follow-up period of 775 days, 42 lead failure events (atrial lead 22, right ventricular pacemaker lead 5, implantable cardioverter defibrillator [ICD] lead 15) were detected. The proportion of lead failures detected only by arrhythmic events, which were not detected by conventional impedance abnormalities, was significantly higher than that detected by impedance abnormalities (arrhythmic event 76.2%, 95% CI: 60.5-87.9%; impedance abnormalities 23.8%, 95% CI: 12.1-39.5%). Twenty-seven events (64.7%) were detected without any alert. Of 15 patients with ICD lead failure, none has experienced inappropriate therapy. RM can detect lead failure earlier, before clinical adverse events. However, CIEDs often diagnose lead failure as just arrhythmic events without any warning. Thus, to detect lead failure earlier, careful human analysis of arrhythmic events is useful. © 2017 Wiley Periodicals, Inc.

Theoretical relation between halo current-plasma energy displacement/deformation in EAST

NASA Astrophysics Data System (ADS)

Khan, Shahab Ud-Din; Khan, Salah Ud-Din; Song, Yuntao; Dalong, Chen

2018-04-01

In this paper, theoretical model for calculating halo current has been developed. This work attained novelty as no theoretical calculations for halo current has been reported so far. This is the first time to use theoretical approach. The research started by calculating points for plasma energy in terms of poloidal and toroidal magnetic field orientations. While calculating these points, it was extended to calculate halo current and to developed theoretical model. Two cases were considered for analyzing the plasma energy when flows down/upward to the diverter. Poloidal as well as toroidal movement of plasma energy was investigated and mathematical formulations were designed as well. Two conducting points with respect to (R, Z) were calculated for halo current calculations and derivations. However, at first, halo current was established on the outer plate in clockwise direction. The maximum generation of halo current was estimated to be about 0.4 times of the plasma current. A Matlab program has been developed to calculate halo current and plasma energy calculation points. The main objective of the research was to establish theoretical relation with experimental results so as to precautionary evaluate the plasma behavior in any Tokamak.

A theory of utility conditionals: Paralogical reasoning from decision-theoretic leakage.

PubMed

Bonnefon, Jean-François

2009-10-01

Many "if p, then q" conditionals have decision-theoretic features, such as antecedents or consequents that relate to the utility functions of various agents. These decision-theoretic features leak into reasoning processes, resulting in various paralogical conclusions. The theory of utility conditionals offers a unified account of the various forms that this phenomenon can take. The theory is built on 2 main components: (1) a representational tool (the utility grid), which summarizes in compact form the decision-theoretic features of a conditional, and (2) a set of folk axioms of decision, which reflect reasoners' beliefs about the way most agents make their decisions. Applying the folk axioms to the utility grid of a conditional allows for the systematic prediction of the paralogical conclusions invited by the utility grid's decision-theoretic features. The theory of utility conditionals significantly extends the scope of current theories of conditional inference and moves reasoning research toward a greater integration with decision-making research.

Experimental and theoretical studies of dipole and quadrupole contributions to the vanadium K-edge XANES for VOPO4.2H2O xerogel

NASA Astrophysics Data System (ADS)

Poumellec, B.; Kraizman, V.; Aifa, Y.; Cortès, R.; Novakovich, A.; Vedrinskii, R.

1998-09-01

Angular dependence of the vanadium K-edge x-ray appearance near-edge structure (XANES) for the VOPO4.2H2O xerogel is thoroughly studied both experimentally and theoretically. The main attention is paid to the pre-edge fine structure (PEFS) of the spectra which was shown earlier to be a useful tool for the atomic short order investigations. Good quantitative agreement between theory and experiment obtained for both dipole and quadrupole contributions to the spectra proves validity of the calculation method developed and enables us to ascertain the nature of all the features in the PEFS's. The p-d mixture effect due to distortion of the central coordination octahedron and the quadrupole transitions are proved to be the only mechanisms responsible for the PEFS formation in the case considered. We show that in order to achieve quantitative agreement between experimental and theoretical spectra, it is necessary to include the effect of atomic vibrations, which makes the forbidden transitions to molecular orbitals of the central octahedron (MOCO's) dipole allowed, and to take into account deviation of the crystal layers from the substrate plane, which is not a single crystal but a texture.

Earlier predictors of eating disorder symptoms in 9-year-old children. A longitudinal study.

PubMed

Parkinson, Kathryn N; Drewett, Robert F; Le Couteur, Ann S; Adamson, Ashley J

2012-08-01

The aim of the study was to examine predictors of eating disorder symptoms in a population based sample at the earliest age at which they can be measured using the Children's Eating Attitudes Test. Data were collected from the longitudinal Gateshead Millennium Study cohort; 609 children participated in the 7 year data sweep (and their mothers and teachers), and 589 children participated in the 9 year data sweep. Eating disorder symptoms at 9 years were higher in boys, and in children from more deprived families. Higher eating disorder symptoms were associated with more body dissatisfaction at 9 years. Higher symptoms were predicted by higher levels of dietary restraint and of emotional symptoms, but not greater body dissatisfaction, 2 years earlier. The study showed that some correlates of high eating disorder symptoms found in adolescents and adults are also found in children, before the rise in diagnosable eating disorders over the pubertal period. Copyright © 2012 Elsevier Ltd. All rights reserved.

Crystal structure and theoretical calculations of Julocrotine, a natural product with antileishmanial activity

NASA Astrophysics Data System (ADS)

Moreira, Rafael Y. O.; Brasil, Davi S. B.; Alves, Cláudio N.; Guilhon, Giselle M. S. P.; Santos, Lourivaldo S.; Arruda, Mara S. P.; Müller, Adolfo H.; Barbosa, Patrícia S.; Abreu, Alcicley S.; Silva, Edilene O.; Rumjanek, Victor M.; Souza, Jaime, Jr.; da Silva, Albérico B. F.; Santos, Regina H. De A.

Julocrotine, N-(2,6-dioxo-1-phenethyl-piperidin-3-yl)-2-methyl-butyramide, is a potent antiproliferative agent against the promastigote and amastigote forms of Leishmania amazonensis (L.). In this work, the crystal structure of Julocrotine was solved by X-ray diffraction, and its geometrical parameters were compared with theoretical calculations at the B3LYP and HF level of theory. IR and NMR spectra also have been obtained and compared with theoretical calculations. IR absorptions calculated with the B3LYP level of theory employed together with the 6-311G+(d,p) basis set, are close to those observed experimentally. Theoretical NMR calculations show little deviation from experimental results. The results show that the theory is in accordance with the experimental data.0

Pronounced non-Arrhenius behaviour of hydrogen-abstractions from toluene and derivatives by phthalimide-N-oxyl radicals: a theoretical study.

PubMed

Hermans, Ive; Jacobs, Pierre; Peeters, Jozef

2008-02-28

Abstraction of hydrogen atoms by pthalimide-N-oxyl radicals is an important step in the N-hydroxyphthalimide catalyzed autoxidation of hydrocarbons. In this contribution, the temperature dependency of this reaction is evaluated by a detailed transition state theory based kinetic analysis for the case of toluene. Tunneling was found to play a very important role, enhancing the rate constant by a factor of 20 at room temperature. As a result, tunneling, in combination with the existence of two distinct rotamers of the transition state, causes a pronounced temperature dependency of the pre-exponential frequency factor, and, as a consequence, marked curvature of the Arrhenius plot. This explains why earlier experimental studies over a limited temperature range around 300 K found formal Arrhenius activation energies and pre-factors that are 4 kcal mol(-1) and three orders of magnitude smaller than the actual energy barrier and the corresponding frequency factor, respectively. Also as a consequence of tunneling, substitution of a deuterium atom for a hydrogen atom causes a large decrease in the rate constant, in agreement with the measured kinetic isotope effects. The present theoretical analysis, complementary to the experimental rate coefficient data, allows for a reliable prediction of the rate coefficient at higher temperatures, relevant for actual autoxidation processes.

Border and surface tracing--theoretical foundations.

PubMed

Brimkov, Valentin E; Klette, Reinhard

2008-04-01

In this paper we define and study digital manifolds of arbitrary dimension, and provide (in particular)a general theoretical basis for curve or surface tracing in picture analysis. The studies involve properties such as one-dimensionality of digital curves and (n-1)-dimensionality of digital hypersurfaces that makes them discrete analogs of corresponding notions in continuous topology. The presented approach is fully based on the concept of adjacency relation and complements the concept of dimension as common in combinatorial topology. This work appears to be the first one on digital manifolds based ona graph-theoretical definition of dimension. In particular, in the n-dimensional digital space, a digital curve is a one-dimensional object and a digital hypersurface is an (n-1)-dimensional object, as it is in the case of curves and hypersurfaces in the Euclidean space. Relying on the obtained properties of digital hypersurfaces, we propose a uniform approach for studying good pairs defined by separations and obtain a classification of good pairs in arbitrary dimension. We also discuss possible applications of the presented definitions and results.

[Once again: theoretical pathology].

PubMed

Bleyl, U

2010-07-01

Theoretical pathology refers to the attempt to reintroduce methodical approaches from the humanities, philosophical logic and "gestalt philosophy" into medical research and pathology. Diseases, in particular disease entities and more complex polypathogenetic mechanisms of disease, have a "gestalt quality" due to the significance of their pathophysiologic coherence: they have a "gestalt". The Research group Theoretical Pathology at the Academy of Science in Heidelberg are credited with having revitalized the philosophical notion of "gestalt" for morphological and pathological diagnostics. Gestalt means interrelated schemes of pathophysiological significance in the mind of the diagnostician. In pathology, additive and associative diagnostic are simply not possible without considering the notion of synthetic entities in Kant's logic.

Theoretical resources for a globalised bioethics.

PubMed

Verkerk, Marian A; Lindemann, Hilde

2011-02-01

In an age of global capitalism, pandemics, far-flung biobanks, multinational drug trials and telemedicine it is impossible for bioethicists to ignore the global dimensions of their field. However, if they are to do good work on the issues that globalisation requires of them, they need theoretical resources that are up to the task. This paper identifies four distinct understandings of 'globalised' in the bioethics literature: (1) a focus on global issues; (2) an attempt to develop a universal ethical theory that can transcend cultural differences; (3) an awareness of how bioethics itself has expanded, with new centres and journals emerging in nearly every corner of the globe; (4) a concern to avoid cultural imperialism in encounters with other societies. Each of these approaches to globalisation has some merit, as will be shown. The difficulty with them is that the standard theoretical tools on which they rely are not designed for cross-cultural ethical reflection. As a result, they leave important considerations hidden. A set of theoretical resources is proposed to deal with the moral puzzles of globalisation. Abandoning idealised moral theory, a normative framework is developed that is sensitive enough to account for differences without losing the broader context in which ethical issues arise. An empirically nourished, self-reflexive, socially inquisitive, politically critical and inclusive ethics allows bioethicists the flexibility they need to pick up on the morally relevant particulars of this situation here without losing sight of the broader cultural contexts in which it all takes place.

Absorption coefficients of silicon: A theoretical treatment

NASA Astrophysics Data System (ADS)

Tsai, Chin-Yi

2018-05-01

A theoretical model with explicit formulas for calculating the optical absorption and gain coefficients of silicon is presented. It incorporates direct and indirect interband transitions and considers the effects of occupied/unoccupied carrier states. The indirect interband transition is calculated from the second-order time-independent perturbation theory of quantum mechanics by incorporating all eight possible routes of absorption or emission of photons and phonons. Absorption coefficients of silicon are calculated from these formulas. The agreements and discrepancies among the calculated results, the Rajkanan-Singh-Shewchun (RSS) formula, and Green's data are investigated and discussed. For example, the RSS formula tends to overestimate the contributions of indirect transitions for cases with high photon energy. The results show that the state occupied/unoccupied effect is almost negligible for silicon absorption coefficients up to the onset of the optical gain condition where the energy separation of Quasi-Femi levels between electrons and holes is larger than the band-gap energy. The usefulness of using the physics-based formulas, rather than semi-empirical fitting ones, for absorption coefficients in theoretical studies of photovoltaic devices is also discussed.

Phylogenomic analysis of Copepoda (Arthropoda, Crustacea) reveals unexpected similarities with earlier proposed morphological phylogenies.

PubMed

Eyun, Seong-Il

2017-01-19

Copepods play a critical role in marine ecosystems but have been poorly investigated in phylogenetic studies. Morphological evidence supports the monophyly of copepods, whereas interordinal relationships continue to be debated. In particular, the phylogenetic position of the order Harpacticoida is still ambiguous and inconsistent among studies. Until now, a small number of molecular studies have been done using only a limited number or even partial genes and thus there is so far no consensus at the order-level. This study attempted to resolve phylogenetic relationships among and within four major copepod orders including Harpacticoida and the phylogenetic position of Copepoda among five other crustacean groups (Anostraca, Cladocera, Sessilia, Amphipoda, and Decapoda) using 24 nuclear protein-coding genes. Phylogenomics has confirmed the monophyly of Copepoda and Podoplea. However, this study reveals surprising differences with the majority of the copepod phylogenies and unexpected similarities with postembryonic characters and earlier proposed morphological phylogenies; More precisely, Cyclopoida is more closely related to Siphonostomatoida than to Harpacticoida which is likely the most basally-branching group of Podoplea. Divergence time estimation suggests that the origin of Harpacticoida can be traced back to the Devonian, corresponding well with recently discovered fossil evidence. Copepoda has a close affinity to the clade of Malacostraca and Thecostraca but not to Branchiopoda. This result supports the hypothesis of the newly proposed clades, Communostraca, Multicrustacea, and Allotriocarida but further challenges the validity of Hexanauplia and Vericrustacea. The first phylogenomic study of Copepoda provides new insights into taxonomic relationships and represents a valuable resource that improves our understanding of copepod evolution and their wide range of ecological adaptations.

Press-fit bipolar radial head arthroplasty, midterm results.

PubMed

Kodde, Izaäk F; Heijink, Andras; Kaas, Laurens; Mulder, Paul G H; van Dijk, C Niek; Eygendaal, Denise

2016-08-01

Theoretical advantages of bipolar compared with monopolar radial head arthroplasty include better accommodation of radiocapitellar malalignment, reduction of capitellar abrasion, and reduction of stress at the bone-implant interfaces. Our purpose was to report the midterm results of press-fit bipolar radial head arthroplasty. Thirty patients were treated by press-fit bipolar radial head arthroplasty for acute fracture of the radial head, failed earlier treatment, or post-traumatic sequelae. Three patients were lost to follow-up. Results are presented for the remaining 27 patients. At mean follow-up of 48 months (range, 28-73), there had been 3 (11%) revisions. Two involved conversion to prosthetic radiocapitellar hemiarthroplasty for symptomatic capitellar abrasion; a third involved exchange of the articular component (ie, head) for instability. In all, the stems appeared well fixed. A prosthesis in a subluxed position accounted for the 1 (4%) additional radiologic failure. The average flexion-extension arc was 136° (range, 120°-145°), and the average pronation-supination arc was 138° (range, 70°-180°). According to the Mayo Elbow Performance Score, the combined excellent and good results accounted for 70%. The overall midterm outcome of this series of 30 press-fit bipolar radial head arthroplasties can be considered favorable. Although the revision rate was 11%, the stems were well fixed in all. There was 1 (4%) additional radiologic failure. We suggest considering a press-fit bipolar radial head prosthesis for acute comminuted radial head fractures with limited bone loss of the proximal radius. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

How to Develop Critical Thinking Skills Within the Armys Officer Education System (OES) Earlier in an Officer’s Career

DTIC Science & Technology

2016-02-13

thinking emerges.”31 Military leaders should minimize bureaucracy when possible in an attempt to facilitate creative thinking . Consequently, a...AIR WAR COLLEGE AIR UNIVERSITY HOW TO DEVELOP CRITICAL THINKING SKILLS WITHIN THE ARMY’S OFFICER EDUCTION SYSTEM (OES) EARLIER IN AN...Force Dragon’s Heart.” iv Abstract Critical thinking skills are required by strategic leaders to solve complex problems in an environment

Earlier initialization of highly active antiretroviral therapy is associated with long-term survival and is cost-effective: findings from a deterministic model of a 10-year Ugandan cohort.

PubMed

Mills, Fergal P; Ford, Nathan; Nachega, Jean B; Bansback, Nicholas; Nosyk, Bohdan; Yaya, Sanni; Mills, Edward J

2012-11-01

Raising the guidelines for the initiation of antiretroviral therapy in resource-limited settings at CD4 T-cell counts of 350 cells per microliter raises concerns about feasibility and cost. We examined costs of this shift using data from Uganda for almost 10 years. We projected total costs of earlier initiation with combined antiretroviral therapy, including inpatient and outpatient services, antiretroviral treatment and treatment for limited HIV-related opportunistic diseases, and benefits expressed in years-of-life-saved over 5- and 30-year time horizons using a deterministic economic model to examine the incremental cost-effectiveness ratio (ICER), expressed in cost per year-of-life-saved (YLS). The model generated ICERs for 5- and 30-year time horizons. Discounting both costs and benefits at 3% annually, for the 5-year analysis, the ICER was $695/YLS and $769 in the 30-year analysis. The results were most sensitive to program cost and the discount rate applied, but they were less sensitive to opportunistic infection treatment costs or the relative-risk reduction from earlier initiation. Program costs varied from 25% to 125%, and the ICER for the lower bound decreased to $491/YLS at 5-years and $574/YLS at 30 years. For the upper bound, the ICER increased to $899 for 5-years and $964 at 30-years. The budget impact of adoption, assuming the same level of program penetration in the community, is $261,651,942 for 5 years and $872,685,561 for 30 years. Our model showed that earlier initiation of combined antiretroviral therapy in Uganda is associated with improved long-term survival and is highly cost-effective, as defined by WHO-CHOICE.

On the Worthwhileness of Theoretical Activities

ERIC Educational Resources Information Center

Hand, Michael

2009-01-01

R.S. Peters' arguments for the worthwhileness of theoretical activities are intended to justify education per se, on the assumption that education is necessarily a matter of initiating people into theoretical activities. If we give up this assumption, we can ask whether Peters' arguments might serve instead to justify the academic curriculum over…

Earlier Visual N1 Latencies in Expert Video-Game Players: A Temporal Basis of Enhanced Visuospatial Performance?

PubMed Central

Latham, Andrew J.; Patston, Lucy L. M.; Westermann, Christine; Kirk, Ian J.; Tippett, Lynette J.

2013-01-01

Increasing behavioural evidence suggests that expert video game players (VGPs) show enhanced visual attention and visuospatial abilities, but what underlies these enhancements remains unclear. We administered the Poffenberger paradigm with concurrent electroencephalogram (EEG) recording to assess occipital N1 latencies and interhemispheric transfer time (IHTT) in expert VGPs. Participants comprised 15 right-handed male expert VGPs and 16 non-VGP controls matched for age, handedness, IQ and years of education. Expert VGPs began playing before age 10, had a minimum 8 years experience, and maintained playtime of at least 20 hours per week over the last 6 months. Non-VGPs had little-to-no game play experience (maximum 1.5 years). Participants responded to checkerboard stimuli presented to the left and right visual fields while 128-channel EEG was recorded. Expert VGPs responded significantly more quickly than non-VGPs. Expert VGPs also had significantly earlier occipital N1s in direct visual pathways (the hemisphere contralateral to the visual field in which the stimulus was presented). IHTT was calculated by comparing the latencies of occipital N1 components between hemispheres. No significant between-group differences in electrophysiological estimates of IHTT were found. Shorter N1 latencies may enable expert VGPs to discriminate attended visual stimuli significantly earlier than non-VGPs and contribute to faster responding in visual tasks. As successful video-game play requires precise, time pressured, bimanual motor movements in response to complex visual stimuli, which in this sample began during early childhood, these differences may reflect the experience and training involved during the development of video-game expertise, but training studies are needed to test this prediction. PMID:24058667

Earlier visual N1 latencies in expert video-game players: a temporal basis of enhanced visuospatial performance?

PubMed

Latham, Andrew J; Patston, Lucy L M; Westermann, Christine; Kirk, Ian J; Tippett, Lynette J

2013-01-01

Increasing behavioural evidence suggests that expert video game players (VGPs) show enhanced visual attention and visuospatial abilities, but what underlies these enhancements remains unclear. We administered the Poffenberger paradigm with concurrent electroencephalogram (EEG) recording to assess occipital N1 latencies and interhemispheric transfer time (IHTT) in expert VGPs. Participants comprised 15 right-handed male expert VGPs and 16 non-VGP controls matched for age, handedness, IQ and years of education. Expert VGPs began playing before age 10, had a minimum 8 years experience, and maintained playtime of at least 20 hours per week over the last 6 months. Non-VGPs had little-to-no game play experience (maximum 1.5 years). Participants responded to checkerboard stimuli presented to the left and right visual fields while 128-channel EEG was recorded. Expert VGPs responded significantly more quickly than non-VGPs. Expert VGPs also had significantly earlier occipital N1s in direct visual pathways (the hemisphere contralateral to the visual field in which the stimulus was presented). IHTT was calculated by comparing the latencies of occipital N1 components between hemispheres. No significant between-group differences in electrophysiological estimates of IHTT were found. Shorter N1 latencies may enable expert VGPs to discriminate attended visual stimuli significantly earlier than non-VGPs and contribute to faster responding in visual tasks. As successful video-game play requires precise, time pressured, bimanual motor movements in response to complex visual stimuli, which in this sample began during early childhood, these differences may reflect the experience and training involved during the development of video-game expertise, but training studies are needed to test this prediction.

Electron temperature maps of the low solar corona: ISCORE results from the total solar eclipse of 1 August 2008 in China

NASA Astrophysics Data System (ADS)

Reginald, Nelson L.; Davila, Joseph M.; St. Cyr, Orville C.; Rabin, Douglas M.

2017-06-01

We conducted an experiment in conjunction with the total solar eclipse of 1 August 2008 in China to determine the thermal electron temperature in the low solar corona close to the solar limb. The instrument, Imaging Spectrograph of Coronal Electrons (ISCORE), consisted of an 8 inch f/10 Schmidt Cassegrain telescope with a thermoelectrically cooled CCD camera at the focal plane. Results are electron temperatures of 1 MK at 1.08 R⊙ and 1.13 R⊙ from the Sun center in the polar and equatorial regions, respectively. This experiment confirms the results of an earlier experiment conducted in conjunction with the total eclipse of 29 March 2006 in Libya, and results are that at a given coronal height the electron temperature in the polar region is larger than at the equatorial region. In this paper we show the importance of using the correct photospheric spectrum pertinent to the solar activity phase at the time of the experiment, which is a required parameter for modeling the underlying theoretical concept for temperature interpretation of the measured intensity ratios using color filters.

Inverse design of an isotropic suspended Kirchhoff rod: theoretical and numerical results on the uniqueness of the natural shape.

PubMed

Bertails-Descoubes, Florence; Derouet-Jourdan, Alexandre; Romero, Victor; Lazarus, Arnaud

2018-04-01

Solving the equations for Kirchhoff elastic rods has been widely explored for decades in mathematics, physics and computer science, with significant applications in the modelling of thin flexible structures such as DNA, hair or climbing plants. As demonstrated in previous experimental and theoretical studies, the natural curvature plays an important role in the equilibrium shape of a Kirchhoff rod, even in the simple case where the rod is isotropic and suspended under gravity. In this paper, we investigate the reverse problem: can we characterize the natural curvature of a suspended isotropic rod, given an equilibrium curve? We prove that although there exists an infinite number of natural curvatures that are compatible with the prescribed equilibrium, they are all equivalent in the sense that they correspond to a unique natural shape for the rod. This natural shape can be computed efficiently by solving in sequence three linear initial value problems, starting from any framing of the input curve. We provide several numerical experiments to illustrate this uniqueness result, and finally discuss its potential impact on non-invasive parameter estimation and inverse design of thin elastic rods.

Inverse design of an isotropic suspended Kirchhoff rod: theoretical and numerical results on the uniqueness of the natural shape

NASA Astrophysics Data System (ADS)

Bertails-Descoubes, Florence; Derouet-Jourdan, Alexandre; Romero, Victor; Lazarus, Arnaud

2018-04-01

Solving the equations for Kirchhoff elastic rods has been widely explored for decades in mathematics, physics and computer science, with significant applications in the modelling of thin flexible structures such as DNA, hair or climbing plants. As demonstrated in previous experimental and theoretical studies, the natural curvature plays an important role in the equilibrium shape of a Kirchhoff rod, even in the simple case where the rod is isotropic and suspended under gravity. In this paper, we investigate the reverse problem: can we characterize the natural curvature of a suspended isotropic rod, given an equilibrium curve? We prove that although there exists an infinite number of natural curvatures that are compatible with the prescribed equilibrium, they are all equivalent in the sense that they correspond to a unique natural shape for the rod. This natural shape can be computed efficiently by solving in sequence three linear initial value problems, starting from any framing of the input curve. We provide several numerical experiments to illustrate this uniqueness result, and finally discuss its potential impact on non-invasive parameter estimation and inverse design of thin elastic rods.

Theoretical Noise Analysis on a Position-sensitive Metallic Magnetic Calorimeter

NASA Technical Reports Server (NTRS)

Smith, Stephen J.

2007-01-01

We report on the theoretical noise analysis for a position-sensitive Metallic Magnetic Calorimeter (MMC), consisting of MMC read-out at both ends of a large X-ray absorber. Such devices are under consideration as alternatives to other cryogenic technologies for future X-ray astronomy missions. We use a finite-element model (FEM) to numerically calculate the signal and noise response at the detector outputs and investigate the correlations between the noise measured at each MMC coupled by the absorber. We then calculate, using the optimal filter concept, the theoretical energy and position resolution across the detector and discuss the trade-offs involved in optimizing the detector design for energy resolution, position resolution and count rate. The results show, theoretically, the position-sensitive MMC concept offers impressive spectral and spatial resolving capabilities compared to pixel arrays and similar position-sensitive cryogenic technologies using Transition Edge Sensor (TES) read-out.

Bowel cancer screening is safe, detects earlier stage cancer and adenomas in 50% of cases: experience of the prevalent round of screening from two first wave centres in the North East of England

PubMed Central

Rajasekhar, P T; Clifford, G M; Lee, T J W; Rutter, M D; Waddup, G; Ritchie, M; Nylander, D; Painter, J; Singh, J; Ward, I; Dempsey, N; Bowes, J; Handley, G; Henry, J; Rees, C J

2012-01-01

Objective The NHS Bowel Cancer Screening Programme (BCSP) began roll-out in 2006 aiming to reduce cancer mortality through detection at an earlier stage. We report results from the prevalent round of screening at two first wave centres and compare with the UK pilot study. Design This is a service evaluation study. Data were collected prospectively for all individuals undergoing faecal occult blood testing (FOBt) and colonoscopy including: uptake and outcomes of FOBt, colonoscopic performance, findings, histological data and complications. Continuous data were compared using a two-tailed test of two proportions. Setting The South of Tyne and Tees Bowel Cancer Screening centres. Patients Participants of the BCSP. Main Outcome Measures 1) Colonoscopy Quality Assurance and 2) Cancer stage shift. Results 195,772 individuals were invited to participate. Uptake was 54% and FOBt positivity 1.7%. 1524 underwent colonoscopy with caecal intubation in 1485 (97%). 180 (12%) cancers were detected. Dukes stages were: 76 (42%) A; 47 (26%) B; 47 (26%) C; 8 (4%) D and 2 (1%) unknown. This demonstrates a significantly earlier stage at diagnosis compared with data from 2867 non-screening detected cancers (p<0.001). Adenomas were detected in 758 (50%). One perforation occurred (0.07%) and two intermediate bleeds requiring transfusion only (0.12%). Both caecal intubation and adenoma detection were significantly higher than in the UK pilot study (p<0.001). Conclusions The prevalent round of screening demonstrates a high adenoma and cancer detection rate and significantly earlier stage at diagnosis. Complications were few providing reassurance regarding safety. Efforts are required to improve uptake. PMID:28839624

Theoretical and Experimental Spectroscopic Analysis of Cyano-Substituted Styrylpyridine Compounds

PubMed Central

Castro, Maria Eugenia; Percino, Maria Judith; Chapela, Victor M.; Ceron, Margarita; Soriano-Moro, Guillermo; Lopez-Cruz, Jorge; Melendez, Francisco J.

2013-01-01

A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)] pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were carried out using the Density Functional Theory (DFT) in both gas and solution phases. For theoretical UV-Vis and 1H NMR spectra, the Time-Dependent DFT (TD-DFT) and the Gauge-Including Atomic Orbital (GIAO) methods were used, respectively. The theoretical characterization matched the experimental measurements, showing a good correlation. The effect of cyano- and methyl-substituents, as well as of the N-atom position in the pyridine ring on the UV-Vis, IR and NMR spectra, was evaluated. The UV-Vis results showed no significant effect due to electron-withdrawing cyano- and electron-donating methyl-substituents. The N-atom position, however, caused a slight change in the maximum absorption wavelengths. The IR normal modes were assigned for the cyano- and methyl-groups. 1H NMR spectra showed the typical doublet signals due to protons in the trans position of a double bond. The theoretical characterization was visibly useful to assign accurately the signals in IR and 1H NMR spectra, as well as to identify the most probable conformation that could be present in the formation of the styrylpyridine-like compounds. PMID:23429190

Panorama of theoretical physics

NASA Astrophysics Data System (ADS)

Mimouni, J.

2012-06-01

We shall start this panorama of theoretical physics by giving an overview of physics in general, this branch of knowledge that has been taken since the scientific revolution as the archetype of the scientific discipline. We shall then proceed in showing in what way theoretical physics from Newton to Maxwell, Einstein, Feynman and the like, in all modesty, could be considered as the ticking heart of physics. By its special mode of inquiry and its tantalizing successes, it has capturing the very spirit of the scientific method, and indeed it has been taken as a role model by other disciplines all the way from the "hard" ones to the social sciences. We shall then review how much we know today of the world of matter, both in term of its basic content and in the way it is structured. We will then present the dreams of today's theoretical physics as a way of penetrating into its psyche, discovering in this way its aspirations and longing in much the same way that a child's dreams tell us about his yearning and craving. Yet our understanding of matter has been going in the past decades through a crisis of sort. As a necessary antidote, we shall thus discuss the pitfalls of dreams pushed too far….

Theoretical study of the gas-phase ozonolysis of beta-pinene (C10H16).

PubMed

Nguyen, T L; Peeters, J; Vereecken, L

2009-07-21

The O3-initiated oxidation of beta-pinene, a monoterpene emitted in forested areas, was theoretically characterized using DFT, CBS-QB3 and CASPT2 quantum chemical calculations combined with statistical kinetic RRKM/master equation analysis and transition state theory. The first-principles based rate coefficient of the initial 03 attack on the exocyclic double bond shows a slight positive temperature dependence, k(tot)T = 1.27 x 10(-22) x T2.64 x exp(-714 K/T) cm3 molecule(-1) s(-1) and is in close agreement with experiment. The resulting primary ozonides are found to give rise to two distinct, non-interconvertible conformers of the predominant Criegee intermediate (CI-1 and CI-2), with subsequent chemistries that are shown to be very different; this crucial aspect of beta-pinene ozonolysis was not taken into account in earlier studies. One of the conformers CI-2--carrying nearly half the total reaction flux--cannot undergo the usual "hydroperoxide channel", thus rationalizing why the OH yield from beta-pinene is barely half of that from alpha-pinene. The predicted first-generation product distribution for atmospheric conditions is consistent with the available experimental data on the overall products. Our final results predict 5% of nopinone formation, 28% OH radicals with 2-oxo-alkyl radical coproducts, 37% of stabilized Criegee intermediates (SCI), 17% lactones, 10% CO2 formed after an intersystem crossing, and 3% of a newly proposed biradical formed from prompt ring opening in the CI. In atmospheric conditions, additional OH production is expected from the stabilized CI-1 conformer via the thermal unimolecular "hydroperoxide channel", whereas the stabilized CI-2 can react with H2O and its dimer, to produce additional nopinone. The expected subsequent chemistries of the large coproduct radicals formed from reactions of the two CI are also addressed in extenso.

Aeroelastic effects in multirotor vehicles. Part 2: Methods of solution and results illustrating coupled rotor/body aeromechanical stability

NASA Technical Reports Server (NTRS)

Venkatesan, C.; Friedmann, P. P.

1987-01-01

This report is a sequel to the earlier report titled, Aeroelastic Effects in Multi-Rotor Vehicles with Application to Hybrid Heavy Lift System, Part 1: Formulation of Equations of Motion (NASA CR-3822). The trim and stability equations are presented for a twin rotor system with a buoyant envelope and an underslung load attached to a flexible supporting structure. These equations are specialized for the case of hovering flight. A stability analysis, for such a vehicle with 31 degrees of freedom, yields a total of 62 eigenvalues. A careful parametric study is performed to identify the various blade and vehicle modes, as well as the coupling between various modes. Finally, it is shown that the coupled rotor/vehicle stability analysis provides information on both the aeroelastic stability as well as complete vehicle dynamic stability. Also presented are the results of an analytical study aimed at predicting the aeromechanical stability of a single rotor helicopter in ground resonance. The theoretical results are found to be in good agreement with the experimental results, thereby validating the analytical model for the dynamics of the coupled rotor/support system.

Using the theoretical domains framework to guide the development of a self-management program for individuals with spinal cord injury: Results from a national stakeholder advisory group.

PubMed

Munce, Sarah E P; Allin, Sonya; Wolfe, Dalton L; Anzai, Karen; Linassi, Gary; Noonan, Vanessa K; Jaglal, Susan B

2017-11-01

To determine the implementation considerations for a targeted self-management program for individuals with spinal cord injury (SCI) from the perspective of a national stakeholder advisory group using the Theoretical Domains Framework (TDF) as a guide. Qualitative descriptive approach. Two focus groups held at the 6 th National Spinal Cord Injury Conference (October 2-4 th , 2014) in Toronto, Ontario, Canada. A total of 25 stakeholders from across Canada participated in focus groups or "brainstorming sessions". The stakeholders included 5 clinicians, 14 researchers, 3 policy makers, and 3 individuals with SCI. Not applicable. Not applicable. All 14 theoretical domains were identified in the brainstorming sessions. No new themes or domains were identified. The need to consider the theoretical domains of Knowledge, Skills, Reinforcement, Intentions, Goals (e.g. the readiness of the individual with SCI), Environmental Context and Resources (e.g. considerations for governance and ownership of the program and a business model for sustainability), as well as Social Influences (e.g. issues of privacy and security in the context of on-line delivery) was identified. The current study provides complementary results to our previous series of studies on the implementation considerations for the development of a targeted self-management program for individuals with SCI by emphasizing the health care professional/health policy perspective. It is anticipated that such a program could not only reduce secondary complications and subsequent inappropriate health care use but it may also improve the quality of life for individuals with SCI and their caregivers.

Dependence of tropical cyclone development on coriolis parameter: A theoretical model

NASA Astrophysics Data System (ADS)

Deng, Liyuan; Li, Tim; Bi, Mingyu; Liu, Jia; Peng, Melinda

2018-03-01

A simple theoretical model was formulated to investigate how tropical cyclone (TC) intensification depends on the Coriolis parameter. The theoretical framework includes a two-layer free atmosphere and an Ekman boundary layer at the bottom. The linkage between the free atmosphere and the boundary layer is through the Ekman pumping vertical velocity in proportion to the vorticity at the top of the boundary layer. The closure of this linear system assumes a simple relationship between the free atmosphere diabatic heating and the boundary layer moisture convergence. Under a set of realistic atmospheric parameter values, the model suggests that the most preferred latitude for TC development is around 5° without considering other factors. The theoretical result is confirmed by high-resolution WRF model simulations in a zero-mean flow and a constant SST environment on an f -plane with different Coriolis parameters. Given an initially balanced weak vortex, the TC-like vortex intensifies most rapidly at the reference latitude of 5°. Thus, the WRF model simulations confirm the f-dependent characteristics of TC intensification rate as suggested by the theoretical model.

Low protein content of drainage fluid is a good predictor for earlier chest tube removal after lobectomy.

PubMed

Olgac, Guven; Cosgun, Tugba; Vayvada, Mustafa; Ozdemir, Atilla; Kutlu, Cemal Asim

2014-10-01

Owing to the great absorption capability of the pleura for transudates, the protein content of draining pleural fluid may be considered as a more adequate determinant than its daily draining amount in the decision-making for earlier chest tube removal. In an a priori pilot study, we observed that the initially draining protein-rich exudate converts to a transudate quickly in most patients after lobectomies. Thus, chest tubes draining high-volume but low-protein fluids can safely be removed earlier in the absence of an air leak. This randomized study aims to investigate the validity and clinical applicability of this hypothesis as well as its influence on the timing for chest tube removal and earlier discharge after lobectomy. Seventy-two consecutive patients undergoing straightforward lobectomy were randomized into two groups. Patients with conditions affecting postoperative drainage and with persisting air leaks beyond the third postoperative day were excluded. Drains were removed if the pleural fluid to blood protein ratio (PrRPl/B) was ≤0.5, regardless of its daily draining amount in the study arm (Group S; n = 38), and patients in the control arm (Group C; n = 34) had their tubes removed if daily drainage was ≤250 ml regardless of its protein content. Patients were discharged home immediately or the following morning after removal of the last drain. All cases were followed up regarding the development of symptomatic pleural effusions and hospital readmissions for a redrainage procedure. Demographic and clinical characteristics as well as the pattern of decrease in PrRPl/B were the same between groups. The mean PrRPl/B was 0.65 and 0.67 (95% CI = 0.60-0.69 and 0.62-0.72) on the first postoperative day, and it remarkably dropped down to 0.39 and 0.33 (95% CI = 0.33-0.45 and 0.27-0.39) on the second day in Groups S and C, respectively, and remained below 0.5 on the third day (repeated-measures of ANOVA design, post hoc 'within-group' comparison of the first

Redesigning Orientation in an Intensive Care Unit Using 2 Theoretical Models.

PubMed

Kozub, Elizabeth; Hibanada-Laserna, Maribel; Harget, Gwen; Ecoff, Laurie

2015-01-01

To accommodate a higher demand for critical care nurses, an orientation program in a surgical intensive care unit was revised and streamlined. Two theoretical models served as a foundation for the revision and resulted in clear clinical benchmarks for orientation progress evaluation. The purpose of the project was to integrate theoretical frameworks into practice to improve the unit orientation program. Performance improvement methods served as a framework for the revision, and outcomes were measured before and after implementation. The revised orientation program increased 1- and 2-year nurse retention and decreased turnover. Critical care knowledge increased after orientation for both the preintervention and postintervention groups. Incorporating a theoretical basis for orientation has been shown to be successful in increasing the number of nurses completing orientation and improving retention, turnover rates, and knowledge gained.

[An earlier diagnosis of depression].

PubMed

Campagne, D M

Data of the last decade indicate that, in the Western world and also in Spain, an important part of general practicioners' consultations are related to mental health, but depression is consistently underdiagnosed. Causes are lack of time and back-up, as well as lack of specific training. In Spain, there is no national health service primary care database with actualized clinical information as to mental health. There is evident clinical interest in a more agile diagnostic, resulting from a recollection of data from voluntary selective screening and continuing evaluation of adult depression along the model used by other National Health Systems. Copyright © 2017 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

Developing a theoretical framework for complex community-based interventions.

PubMed

Angeles, Ricardo N; Dolovich, Lisa; Kaczorowski, Janusz; Thabane, Lehana

2014-01-01

Applying existing theories to research, in the form of a theoretical framework, is necessary to advance knowledge from what is already known toward the next steps to be taken. This article proposes a guide on how to develop a theoretical framework for complex community-based interventions using the Cardiovascular Health Awareness Program as an example. Developing a theoretical framework starts with identifying the intervention's essential elements. Subsequent steps include the following: (a) identifying and defining the different variables (independent, dependent, mediating/intervening, moderating, and control); (b) postulating mechanisms how the independent variables will lead to the dependent variables; (c) identifying existing theoretical models supporting the theoretical framework under development; (d) scripting the theoretical framework into a figure or sets of statements as a series of hypotheses, if/then logic statements, or a visual model; (e) content and face validation of the theoretical framework; and (f) revising the theoretical framework. In our example, we combined the "diffusion of innovation theory" and the "health belief model" to develop our framework. Using the Cardiovascular Health Awareness Program as the model, we demonstrated a stepwise process of developing a theoretical framework. The challenges encountered are described, and an overview of the strategies employed to overcome these challenges is presented.

Experimental and theoretical study on Raman spectra of magnesium fluoride clusters and solids.

PubMed

Neelamraju, S; Bach, A; Schön, J C; Fischer, D; Jansen, M

2012-11-21

In this study, the Raman and IR spectra of a large number of isomers of MgF(2) clusters and of possible bulk polymorphs of MgF(2) are calculated and compared with experimental data observed using a low-temperature atom beam deposition. The bulk polymorphs were taken from earlier work, while the cluster modifications for the neutral (MgF(2))(n) (n = 1-10) clusters and charged clusters (up to the trimer anion and cation, (Mg(3)F(7))(-) and (Mg(3)F(5))(+), respectively) are determined in the present work by global energy landscape explorations using simulated annealing. These theoretical calculations are complemented by an experimental study on both the vapor phase and the deposited films of MgF(2), which are generated in a low-temperature atom beam deposition setup for the synthesis of MgF(2) bulk phases. The MgF(2) vapor and film are characterized via Raman spectroscopy of the MgF(2) gas phase species embedded in an Ar-matrix and of the MgF(2)-films deposited onto a cooled substrate, respectively. We find that, in the vapor phase, there are monomers and dimers and charged species to be present in our experimental setup. Furthermore, the results suggest that in the amorphous bulk MgF(2), rutile-like domains are present and MgF(2) clusters similar to those in the matrix. Finally, peaks at about 800 cm(-1), which are in the same range as the A(g) modes of clusters with dangling fluorine atoms connected to three-coordinated Mg atoms, indicate that such dangling bonds are also present in amorphous MgF(2).

Insulator-based dielectrophoresis of microorganisms: theoretical and experimental results.

PubMed

Moncada-Hernandez, Hector; Baylon-Cardiel, Javier L; Pérez-González, Victor H; Lapizco-Encinas, Blanca H

2011-09-01

Dielectrophoresis (DEP) is the motion of particles due to polarization effects in nonuniform electric fields. DEP has great potential for handling cells and is a non-destructive phenomenon. It has been utilized for different cell analysis, from viability assessments to concentration enrichment and separation. Insulator-based DEP (iDEP) provides an attractive alternative to conventional electrode-based systems; in iDEP, insulating structures are used to generate nonuniform electric fields, resulting in simpler and more robust devices. Despite the rapid development of iDEP microdevices for applications with cells, the fundamentals behind the dielectrophoretic behavior of cells has not been fully elucidated. Understanding the theory behind iDEP is necessary to continue the progress in this field. This work presents the manipulation and separation of bacterial and yeast cells with iDEP. A computational model in COMSOL Multiphysics was employed to predict the effect of direct current-iDEP on cells suspended in a microchannel containing an array of insulating structures. The model allowed predicting particle behavior, pathlines and the regions where dielectrophoretic immobilization should occur. Experimental work was performed at the same operating conditions employed with the model and results were compared, obtaining good agreement. This is the first report on the mathematical modeling of the dielectrophoretic response of yeast and bacterial cells in a DC-iDEP microdevice. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding ferromagnetic hysteresis: A theoretical approach

NASA Astrophysics Data System (ADS)

Gangopadhyay, Bijan Kumar

2018-05-01

This work presents a theoretical-mathematical model for the ferromagnetic hysteresis. Theoretical understanding on ferromagnetism can be achieved through addressing the self-interaction propensity between the magnetic dipole moments associated with the magnetic domains, in conjunction with the pinning effects of the dipoles with the defects in the domain sites. An expression which relates ferromagnetic magnetization to the effective magnetic field was established in our previous work (AIP Conference Proceedings 1665, 130042 (2015)). Using this relation and solving for the reversible and the irreversible components of the magnetization, we successfully show that the magnetic saturation and the magnetic remanence can be achieved theoretically. This work also estimates the range of the external field that can be used to trace a reversible M-H curve.

Experimental and theoretical study of the electronic spectrum of the BAr2 complex: Transition to the excited valence B(2s2p2 2D) state

NASA Astrophysics Data System (ADS)

Krumrine, Jennifer R.; Alexander, Millard H.; Yang, Xin; Dagdigian, Paul J.

2000-03-01

The 2s2p22D←2s22p 2P valence transition in the BAr2 cluster is investigated in a collaborative experimental and theoretical study. Laser fluorescence excitation spectra of a supersonic expansion of B atoms entrained in Ar at high source backing pressures display several features not assignable to the BAr complex. Resonance fluorescence is not observed, but instead emission from the lower 3s state. Size-selected fluorescence depletion spectra show that these features in the excitation spectrum are primarily due to the BAr2 complex. This electronic transition within BAr2 is modeled theoretically, similarly to our earlier study of the 3s←2p transition [M. H. Alexander et al., J. Chem. Phys. 106, 6320 (1997)]. The excited potential energy surfaces of the fivefold degenerate B(2s2p22D) state within the ternary complex are computed in a pairwise-additive model employing diatomic BAr potential energy curves which reproduce our previous experimental observations on the electronic states emanating from the B(2D)+Ar asymptote. The simulated absorption spectrum reproduces reasonably well the observed fluorescence depletion spectrum. The theoretical model lends insight into the energetics of the approach of B to multiple Ar atoms, and how the orientation of B p-orbitals governs the stability of the complex.

Application of the Theoretical Domains Framework and the Behaviour Change Wheel to Understand Physicians' Behaviors and Behavior Change in Using Temporary Work Modifications for Return to Work: A Qualitative Study.

PubMed

Horppu, Ritva; Martimo, K P; MacEachen, E; Lallukka, T; Viikari-Juntura, E

2018-03-01

Purpose Applying the theoretical domains framework (TDF) and the Behaviour Change Wheel (BCW) to understand physicians' behaviors and behavior change in using temporary work modifications (TWMs) for return to work (RTW). Methods Interviews and focus group discussions were conducted with 15 occupational physicians (OPs). Responses were coded using the TDF and the BCW. Results Key behaviors related to applying TWMs were initiating the process with the employee, making recommendations to the workplace, and following up the process. OP behaviors were influenced by several factors related to personal capability and motivation, and opportunities provided by the physical and social environment. Capability comprised relevant knowledge and skills related to applying TWMs, remembering to initiate TWMS and monitor the process, and being accustomed to reflective practice. Opportunity comprised physical resources (e.g., time, predefined procedures, and availability of modified work at companies), and social pressure from stakeholders. Motivation comprised conceptions of a proper OP role, confidence to carry out TWMs, personal RTW-related goals, beliefs about the outcomes of one's actions, feedback received from earlier cases, and feelings related to applying TWMs. OPs' perceived means to target these identified factors were linked to the following BCW intervention functions: education, training, persuasion, environmental restructuring, and enablement. The results suggest that at least these functions should be considered when designing future interventions. Conclusions Our study illustrates how theoretical frameworks TDF and BCW can be utilized in a RTW context to understand which determinants of physicians' behavior need to be targeted, and how, to promote desired behaviors.

Information-theoretic metamodel of organizational evolution

NASA Astrophysics Data System (ADS)

Sepulveda, Alfredo

2011-12-01

Social organizations are abstractly modeled by holarchies---self-similar connected networks---and intelligent complex adaptive multiagent systems---large networks of autonomous reasoning agents interacting via scaled processes. However, little is known of how information shapes evolution in such organizations, a gap that can lead to misleading analytics. The research problem addressed in this study was the ineffective manner in which classical model-predict-control methods used in business analytics attempt to define organization evolution. The purpose of the study was to construct an effective metamodel for organization evolution based on a proposed complex adaptive structure---the info-holarchy. Theoretical foundations of this study were holarchies, complex adaptive systems, evolutionary theory, and quantum mechanics, among other recently developed physical and information theories. Research questions addressed how information evolution patterns gleamed from the study's inductive metamodel more aptly explained volatility in organization. In this study, a hybrid grounded theory based on abstract inductive extensions of information theories was utilized as the research methodology. An overarching heuristic metamodel was framed from the theoretical analysis of the properties of these extension theories and applied to business, neural, and computational entities. This metamodel resulted in the synthesis of a metaphor for, and generalization of organization evolution, serving as the recommended and appropriate analytical tool to view business dynamics for future applications. This study may manifest positive social change through a fundamental understanding of complexity in business from general information theories, resulting in more effective management.

The structure of geopolymers - Theoretical studies

NASA Astrophysics Data System (ADS)

Koleżyński, Andrzej; Król, Magdalena; Żychowicz, Mikołaj

2018-07-01

This work presents the results of DFT and classical mechanics' calculations and theoretical analysis of geopolymer structure. The calculations were carried out using a bottom-up approach (from small oligomers to clusters with increasing size) for various Si:Al ratio. For all model structures after geometry optimization, respective IR spectra were simulated and compared with the experimental ones. The obtained results show that the concordance of simulated spectra with the experiment, for a given Si:Al ratio, increases with the size of the cluster and increasing local order. Moreover, the increase of the level of local disorder (structure "openness") results in significant band splitting, not observable in real geopolymers. This suggest that, in the case of real geopolymeric structures one can expect the presence of reasonably big, ordered structural fragments, analogous to zeolites.

Ecological Research Division Theoretical Ecology Program. [Contains abstracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-10-01

This report presents the goals of the Theoretical Ecology Program and abstracts of research in progress. Abstracts cover both theoretical research that began as part of the terrestrial ecology core program and new projects funded by the theoretical program begun in 1988. Projects have been clustered into four major categories: Ecosystem dynamics; landscape/scaling dynamics; population dynamics; and experiment/sample design.

Experimental and Theoretical Analysis of Sound Absorption Properties of Finely Perforated Wooden Panels

PubMed Central

Song, Boqi; Peng, Limin; Fu, Feng; Liu, Meihong; Zhang, Houjiang

2016-01-01

Perforated wooden panels are typically utilized as a resonant sound absorbing material in indoor noise control. In this paper, the absorption properties of wooden panels perforated with tiny holes of 1–3 mm diameter were studied both experimentally and theoretically. The Maa-MPP (micro perforated panels) model and the Maa-Flex model were applied to predict the absorption regularities of finely perforated wooden panels. A relative impedance comparison and full-factorial experiments were carried out to verify the feasibility of the theoretical models. The results showed that the Maa-Flex model obtained good agreement with measured results. Control experiments and measurements of dynamic mechanical properties were carried out to investigate the influence of the wood characteristics. In this study, absorption properties were enhanced by sound-induced vibration. The relationship between the dynamic mechanical properties and the panel mass-spring vibration absorption was revealed. While the absorption effects of wood porous structure were not found, they were demonstrated theoretically by using acoustic wave propagation in a simplified circular pipe with a suddenly changed cross-section model. This work provides experimental and theoretical guidance for perforation parameter design. PMID:28774063

Experimental and Theoretical Analysis of Sound Absorption Properties of Finely Perforated Wooden Panels.

PubMed

Song, Boqi; Peng, Limin; Fu, Feng; Liu, Meihong; Zhang, Houjiang

2016-11-22

Perforated wooden panels are typically utilized as a resonant sound absorbing material in indoor noise control. In this paper, the absorption properties of wooden panels perforated with tiny holes of 1-3 mm diameter were studied both experimentally and theoretically. The Maa-MPP (micro perforated panels) model and the Maa-Flex model were applied to predict the absorption regularities of finely perforated wooden panels. A relative impedance comparison and full-factorial experiments were carried out to verify the feasibility of the theoretical models. The results showed that the Maa-Flex model obtained good agreement with measured results. Control experiments and measurements of dynamic mechanical properties were carried out to investigate the influence of the wood characteristics. In this study, absorption properties were enhanced by sound-induced vibration. The relationship between the dynamic mechanical properties and the panel mass-spring vibration absorption was revealed. While the absorption effects of wood porous structure were not found, they were demonstrated theoretically by using acoustic wave propagation in a simplified circular pipe with a suddenly changed cross-section model. This work provides experimental and theoretical guidance for perforation parameter design.

The response of aboveground plant productivity to earlier snowmelt and summer warming in an Arctic ecosystem

NASA Astrophysics Data System (ADS)

Livensperger, C.; Steltzer, H.; Darrouzet-Nardi, A.; Sullivan, P.; Wallenstein, M. D.; Weintraub, M. N.

2012-12-01

Plant communities in the Arctic are undergoing changes in structure and function due to shifts in seasonality from changing winters and summer warming. These changes will impact biogeochemical cycling, surface energy balance, and functioning of vertebrate and invertebrate communities. To examine seasonal controls on aboveground net primary production (ANPP) in a moist acidic tundra ecosystem in northern Alaska, we shifted the growing season by accelerating snowmelt (using radiation absorbing shadecloth) and warming air and soil temperature (using 1 m2 open-top chambers), individually and in combination. After three years, we measured ANPP by harvesting up to 16 individual ramets, tillers and rhizomes for each of 7 plant species, including two deciduous shrubs, two graminoids, two evergreen shrubs and one forb during peak season. Our results show that ANPP per stem summed across the 7 species increased when snow melt occurred earlier. However, standing biomass, excluding current year growth, was also greater. The ratio of ANPP/standing biomass decreased in all treatments compared to the control. ANPP per unit standing biomass summed for the four shrub species decreases due to summer warming alone or in combination with early snowmelt; however early snowmelt alone did not lead to lower ANPP for the shrubs. ANPP per tiller or rhizome summed for the three herbaceous species increased in response to summer warming. Understanding the differential response of plants to changing seasonality will inform predictions of future Arctic plant community structure and function.

A Theoretical Trombone

ERIC Educational Resources Information Center

LoPresto, Michael C.

2014-01-01

What follows is a description of a theoretical model designed to calculate the playing frequencies of the musical pitches produced by a trombone. The model is based on quantitative treatments that demonstrate the effects of the flaring bell and cup-shaped mouthpiece sections on these frequencies and can be used to calculate frequencies that…

Staying theoretically sensitive when conducting grounded theory research.

PubMed

Reay, Gudrun; Bouchal, Shelley Raffin; A Rankin, James

2016-09-01

Background Grounded theory (GT) is founded on the premise that underlying social patterns can be discovered and conceptualised into theories. The method and need for theoretical sensitivity are best understood in the historical context in which GT was developed. Theoretical sensitivity entails entering the field with no preconceptions, so as to remain open to the data and the emerging theory. Investigators also read literature from other fields to understand various ways to construct theories. Aim To explore the concept of theoretical sensitivity from a classical GT perspective, and discuss the ontological and epistemological foundations of GT. Discussion Difficulties in remaining theoretically sensitive throughout research are discussed and illustrated with examples. Emergence - the idea that theory and substance will emerge from the process of comparing data - and staying open to the data are emphasised. Conclusion Understanding theoretical sensitivity as an underlying guiding principle of GT helps the researcher make sense of important concepts, such as delaying the literature review, emergence and the constant comparative method (simultaneous collection, coding and analysis of data). Implications for practice Theoretical sensitivity and adherence to the GT research method allow researchers to discover theories that can bridge the gap between theory and practice.

Experimental and theoretical rotordynamic stiffness coefficients for a three-stage brush seal

NASA Astrophysics Data System (ADS)

Pugachev, A. O.; Deckner, M.

2012-08-01

Experimental and theoretical results are presented for a multistage brush seal. Experimental stiffness is obtained from integrating circumferential pressure distribution measured in seal cavities. A CFD analysis is used to predict seal performance. Bristle packs are modeled by the porous medium approach. Leakage is predicted well by the CFD method. Theoretical stiffness coefficients are in reasonable agreement with the measurements. Experimental results are also compared with a three-teeth-on-stator labyrinth seal. The multistage brush seal gives about 60% leakage reduction over the labyrinth seal. Rotordynamic stiffness coefficients are also improved: the brush seal has positive direct stiffness and smaller cross-coupled stiffness.

Theoretical rationale for music selection in oncology intervention research: an integrative review.

PubMed

Burns, Debra S

2012-01-01

Music-based interventions have helped patients with cancer improve their quality of life, decrease treatment related distress, and manage pain. However, quantitative findings from music intervention studies are inconsistent. The purpose of this review was to explore the theoretical underpinnings for the selection of the music stimuli used to influence targeted outcomes. It was hypothesized that disparate findings were due in part to the atheoretical nature of music selection and the resulting diversity in music stimuli between and within studies. A systematic research synthesis including a comprehensive database and reference list search resulted in 22 studies. Included studies were compiled into two tables cataloging intervention theory, intervention content, and outcomes. A majority of studies did not provide a rationale or intervention theory for the delivery of music or choice of outcomes. Recorded music was the most common delivery method, but the specific music was rarely included within the report. Only two studies that included a theoretical framework reported null results on at least some of the outcomes. Null results are partially explained by an incomplete or mismatch in intervention theory and music selection and delivery. While the inclusion of an intervention theory does not guarantee positive results, including a theoretical rationale for the use of music, particular therapeutic processes or mechanisms, and the specifics of how music is selected and delivered increases scientific rigor and the probability of clinical translation.

Giant-Magnetoresistance(GMR) Siegel KEY FIRST Experimental Discovery Decade-Earlier PRE-``Fert"-``Gruenberg" in Nuc"el"ar ``Super"alloys: Science?;``SEANCE!!!; Ethics?; SHMETHICS!!!

NASA Astrophysics Data System (ADS)

Hoffman, R.; Siegel, E.

2010-03-01

(So MIScalled) ``Fert"-``Grunberg"[PRL(1988;1989)] GMR 2007 physics Nobel/Wolf/Japan-Prizes VS. decade-earlier(1973-1977) KEY FIRST Siegel at:Westin"kl"ouse/PSEG/IAEA/ABB[google:``Martin Ebner"(94-04) in financial media]/Vattenfall/Wallenbergs/nuc"el"ar-DoE Labs[at flickr.com, search on ``Giant- Magnotoresistance''; find: Intl.Conf.Mag.Alloys & Oxides(ICMAO), Haifa(Aug./1977); J.Mag.Mag.Mtls,(JMMM)7,312(1978)``unavailable: not yet scanned''/modified(last R(H) GMR Figs(7;8) deleted!!!) on JMMM/Reed-Elsevier website until 7/29/08 conveniently one- half-year after last (Nobel)award(12/2007); conveniently effectively deleted!!!; google: ``If Leaks Could Kill''; many APS/MRS Mtgs(1970s)<<<1988/1989] decade-earlier GMR: (1978)<<< (1988); 1988-1978 =10 years = one full decadeprecedence!!!] first experimental discovery in (so MIScalled) ``super''alloys [182/82, Hastelloy-X, 600, 690(!!!), Stainless-Steels: ANY/ALL!!!] generic endemic Wigner's[JAP,17,857(1946)]- disease/Ostwald-ripening/spinodal-decomposition/overageing- embrittlement/ thermo-mechanical-INstability!

Field evidence for earlier leaf-out dates in alpine grassland on the eastern Tibetan Plateau from 1990 to 2006.

PubMed

Zhou, H K; Yao, B Q; Xu, W X; Ye, X; Fu, J J; Jin, Y X; Zhao, X Q

2014-08-01

Worldwide, many plant species are experiencing an earlier onset of spring phenophases due to climate warming. Rapid recent temperature increases on the Tibetan Plateau (TP) have triggered changes in the spring phenology of the local vegetation. However, remote sensing studies of the land surface phenology have reached conflicting interpretations about green-up patterns observed on the TP since the mid-1990s. We investigated this issue using field phenological observations from 1990 to 2006, for 11 dominant plants on the TP at the levels of species, families (Gramineae-grasses and Cyperaceae-sedges) and vegetation communities (alpine meadow and alpine steppe). We found a significant trend of earlier leaf-out dates for one species (Koeleria cristata). The leaf-out dates of both Gramineae and Cyperaceae had advanced (the latter significantly, starting an average of 9 days later per year than the former), but the correlation between them was significant. The leaf-out dates of both vegetation communities also advanced, but the pattern was only significant in the alpine meadow. This study provides the first field evidence of advancement in spring leaf phenology on the TP and suggests that the phenology of the alpine steppe can differ from that of the alpine meadow. These findings will be useful for understanding ecosystem responses to climate change and for grassland management on the TP. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Theoretical Definition of Instructor Role in Computer-Managed Instruction.

ERIC Educational Resources Information Center

McCombs, Barbara L.; Dobrovolny, Jacqueline L.

This report describes the results of a theoretical analysis of the ideal role functions of the Computer Managed Instruction (CMI) instructor. Concepts relevant to instructor behavior are synthesized from both cognitive and operant learning theory perspectives, and the roles allocated to instructors by seven large-scale operational CMI systems are…

Theoretical Approaches in Evolutionary Ecology: Environmental Feedback as a Unifying Perspective.

PubMed

Lion, Sébastien

2018-01-01

Evolutionary biology and ecology have a strong theoretical underpinning, and this has fostered a variety of modeling approaches. A major challenge of this theoretical work has been to unravel the tangled feedback loop between ecology and evolution. This has prompted the development of two main classes of models. While quantitative genetics models jointly consider the ecological and evolutionary dynamics of a focal population, a separation of timescales between ecology and evolution is assumed by evolutionary game theory, adaptive dynamics, and inclusive fitness theory. As a result, theoretical evolutionary ecology tends to be divided among different schools of thought, with different toolboxes and motivations. My aim in this synthesis is to highlight the connections between these different approaches and clarify the current state of theory in evolutionary ecology. Central to this approach is to make explicit the dependence on environmental dynamics of the population and evolutionary dynamics, thereby materializing the eco-evolutionary feedback loop. This perspective sheds light on the interplay between environmental feedback and the timescales of ecological and evolutionary processes. I conclude by discussing some potential extensions and challenges to our current theoretical understanding of eco-evolutionary dynamics.

Theoretical results which strengthen the hypothesis of electroweak bioenantioselection

NASA Astrophysics Data System (ADS)

Zanasi, R.; Lazzeretti, P.; Ligabue, A.; Soncini, A.

1999-03-01

It is shown via a large series of numerical tests on two fundamental organic molecules, the L-α-amino acid L-valine and the sugar precursor hydrated D-glyceraldheyde, that the ab initio calculation of the parity-violating energy shift, at the random-phase approximation level of accuracy, provides results that are about one order of magnitude larger than those obtained by means of less accurate methods employed previously. These findings would make more plausible the hypothesis of electroweak selection of natural enantiomers via the Kondepudi-Nelson scenario, or could imply that Salam phase-transition temperature is higher than previously inferred: accordingly, the hypothesis of terrestrial origin of life would become more realistic.

Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules

NASA Astrophysics Data System (ADS)

Amami, Sadek Mohamed Fituri

In the last twenty years, significant progress has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, different theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy electron-impact ionization of Neon and Argon for different orbital states. There is a very recent interest in studying ionization of Laser aligned atoms in order to get a better understanding about electron impact ionization of molecules. In the next part of this dissertation, results will be presented for electron-impact ionization of three laser aligned atoms, Mg, Ca, and Na. The comparison between the theory and experiment showed that our three body distorted wave (3DW) model gave excellent agreement with experiment in the scattering plane but very poor agreement perpendicular to the scattering plane. An explanation for this poor agreement out of the scattering plane has been provided by comparing our theoretical results with those of the time depended close coupling (TDCC) model and this explanation is also provided in this dissertation. Recently, significant attention has been directed towards obtaining a better under-standing of electron-impact ionization of molecules which are significantly more challenging than atoms. In the last part of this dissertation, results will be presented for electron-impact ionization of three different molecules (N2 , H2O, and CH4) which have been studied comprehensively using different theoretical approximations for different types of geometries. The published papers in

Elucidating Grinding Mechanism by Theoretical and Experimental Investigations.

PubMed

Ullah, Amm Sharif; Caggiano, Alessandra; Kubo, Akihiko; Chowdhury, M A K

2018-02-09

Grinding is one of the essential manufacturing processes for producing brittle or hard materials-based precision parts (e.g., optical lenses). In grinding, a grinding wheel removes the desired amount of material by passing the same area on the workpiece surface multiple times. How the topography of a workpiece surface evolves with these passes is thus an important research issue, which has not yet been addressed elaborately. The present paper tackles this issue from both the theoretical and the experimental points of view. In particular, this paper presents the results of experimental and theoretical investigations on the multi-pass surface grinding operations where the workpiece surface is made of glass and the grinding wheel consists of cBN abrasive grains. Both investigations confirm that a great deal of stochasticity is involved in the grinding mechanism, and the complexity of the workpiece surface gradually increases along with the number of passes.

The Charm of Theoretical Physics (1958-1993)

NASA Astrophysics Data System (ADS)

Maiani, Luciano; Bonolis, Luisa

2017-12-01

Personal recollections on theoretical particle physics in the years when the Standard Theory was formed. In the background, the remarkable development of Italian theoretical physics in the second part of the last century, with great personalities like Bruno Touschek, Raoul Gatto, Nicola Cabibbo and their schools.

Aperture Array Photonic Metamaterials: Theoretical approaches, numerical techniques and a novel application

NASA Astrophysics Data System (ADS)

Lansey, Eli

Optical or photonic metamaterials that operate in the infrared and visible frequency regimes show tremendous promise for solving problems in renewable energy, infrared imaging, and telecommunications. However, many of the theoretical and simulation techniques used at lower frequencies are not applicable to this higher-frequency regime. Furthermore, technological and financial limitations of photonic metamaterial fabrication increases the importance of reliable theoretical models and computational techniques for predicting the optical response of photonic metamaterials. This thesis focuses on aperture array metamaterials. That is, a rectangular, circular, or other shaped cavity or hole embedded in, or penetrating through a metal film. The research in the first portion of this dissertation reflects our interest in developing a fundamental, theoretical understanding of the behavior of light's interaction with these aperture arrays, specifically regarding enhanced optical transmission. We develop an approximate boundary condition for metals at optical frequencies, and a comprehensive, analytical explanation of the physics underlying this effect. These theoretical analyses are augmented by computational techniques in the second portion of this thesis, used both for verification of the theoretical work, and solving more complicated structures. Finally, the last portion of this thesis discusses the results from designing, fabricating and characterizing a light-splitting metamaterial.

Efficient field-theoretic simulation of polymer solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villet, Michael C.; Fredrickson, Glenn H., E-mail: ghf@mrl.ucsb.edu; Department of Materials, University of California, Santa Barbara, California 93106

2014-12-14

We present several developments that facilitate the efficient field-theoretic simulation of polymers by complex Langevin sampling. A regularization scheme using finite Gaussian excluded volume interactions is used to derive a polymer solution model that appears free of ultraviolet divergences and hence is well-suited for lattice-discretized field theoretic simulation. We show that such models can exhibit ultraviolet sensitivity, a numerical pathology that dramatically increases sampling error in the continuum lattice limit, and further show that this pathology can be eliminated by appropriate model reformulation by variable transformation. We present an exponential time differencing algorithm for integrating complex Langevin equations for fieldmore » theoretic simulation, and show that the algorithm exhibits excellent accuracy and stability properties for our regularized polymer model. These developments collectively enable substantially more efficient field-theoretic simulation of polymers, and illustrate the importance of simultaneously addressing analytical and numerical pathologies when implementing such computations.« less

Theoretical Sum Frequency Generation Spectroscopy of Peptides

PubMed Central

2015-01-01

Vibrational sum frequency generation (SFG) has become a very promising technique for the study of proteins at interfaces, and it has been applied to important systems such as anti-microbial peptides, ion channel proteins, and human islet amyloid polypeptide. Moreover, so-called “chiral” SFG techniques, which rely on polarization combinations that generate strong signals primarily for chiral molecules, have proven to be particularly discriminatory of protein secondary structure. In this work, we present a theoretical strategy for calculating protein amide I SFG spectra by combining line-shape theory with molecular dynamics simulations. We then apply this method to three model peptides, demonstrating the existence of a significant chiral SFG signal for peptides with chiral centers, and providing a framework for interpreting the results on the basis of the dependence of the SFG signal on the peptide orientation. We also examine the importance of dynamical and coupling effects. Finally, we suggest a simple method for determining a chromophore’s orientation relative to the surface using ratios of experimental heterodyne-detected signals with different polarizations, and test this method using theoretical spectra. PMID:25203677

Information-Theoretic Assessment of Sample Imaging Systems

NASA Technical Reports Server (NTRS)

Huck, Friedrich O.; Alter-Gartenberg, Rachel; Park, Stephen K.; Rahman, Zia-ur

1999-01-01

By rigorously extending modern communication theory to the assessment of sampled imaging systems, we develop the formulations that are required to optimize the performance of these systems within the critical constraints of image gathering, data transmission, and image display. The goal of this optimization is to produce images with the best possible visual quality for the wide range of statistical properties of the radiance field of natural scenes that one normally encounters. Extensive computational results are presented to assess the performance of sampled imaging systems in terms of information rate, theoretical minimum data rate, and fidelity. Comparisons of this assessment with perceptual and measurable performance demonstrate that (1) the information rate that a sampled imaging system conveys from the captured radiance field to the observer is closely correlated with the fidelity, sharpness and clarity with which the observed images can be restored and (2) the associated theoretical minimum data rate is closely correlated with the lowest data rate with which the acquired signal can be encoded for efficient transmission.

Rock Fracture Toughness Under Mode II Loading: A Theoretical Model Based on Local Strain Energy Density

NASA Astrophysics Data System (ADS)

Rashidi Moghaddam, M.; Ayatollahi, M. R.; Berto, F.

2018-01-01

The values of mode II fracture toughness reported in the literature for several rocks are studied theoretically by using a modified criterion based on strain energy density averaged over a control volume around the crack tip. The modified criterion takes into account the effect of T-stress in addition to the singular terms of stresses/strains. The experimental results are related to mode II fracture tests performed on the semicircular bend and Brazilian disk specimens. There are good agreements between theoretical predictions using the generalized averaged strain energy density criterion and the experimental results. The theoretical results reveal that the value of mode II fracture toughness is affected by the size of control volume around the crack tip and also the magnitude and sign of T-stress.

Python for Information Theoretic Analysis of Neural Data

PubMed Central

Ince, Robin A. A.; Petersen, Rasmus S.; Swan, Daniel C.; Panzeri, Stefano

2008-01-01

Information theory, the mathematical theory of communication in the presence of noise, is playing an increasingly important role in modern quantitative neuroscience. It makes it possible to treat neural systems as stochastic communication channels and gain valuable, quantitative insights into their sensory coding function. These techniques provide results on how neurons encode stimuli in a way which is independent of any specific assumptions on which part of the neuronal response is signal and which is noise, and they can be usefully applied even to highly non-linear systems where traditional techniques fail. In this article, we describe our work and experiences using Python for information theoretic analysis. We outline some of the algorithmic, statistical and numerical challenges in the computation of information theoretic quantities from neural data. In particular, we consider the problems arising from limited sampling bias and from calculation of maximum entropy distributions in the presence of constraints representing the effects of different orders of interaction in the system. We explain how and why using Python has allowed us to significantly improve the speed and domain of applicability of the information theoretic algorithms, allowing analysis of data sets characterized by larger numbers of variables. We also discuss how our use of Python is facilitating integration with collaborative databases and centralised computational resources. PMID:19242557

Laser-induced damage of fused silica optics at 355 nm due to backward stimulated Brillouin scattering: experimental and theoretical results.

PubMed

Lamaignère, Laurent; Gaudfrin, Kévin; Donval, Thierry; Natoli, Jeanyves; Sajer, Jean-Michel; Penninckx, Denis; Courchinoux, Roger; Diaz, Romain

2018-04-30

Forward pump pulses with nanosecond duration are able to generate an acoustic wave via electrostriction through a few centimeters of bulk silica. Part of the incident energy is then scattered back on this sound wave, creating a backward Stokes pulse. This phenomenon known as stimulated Brillouin scattering (SBS) might induce first energy-loss, variable change of the temporal waveform depending on the location in the spatial profile making accurate metrology impossible, and moreover it might also initiate front surface damage making the optics unusable. Experiments performed on thick fused silica optics at 355 nm with single longitudinal mode pulses allowed us to detect, observe and quantify these backward pulses. Experimental results are first compared to theoretical calculations in order to strengthen our confidence in metrology. On this basis a phase-modulator has been implemented on the continuous-wave seeders of the lasers leading to pulses with a wide spectrum that suppress SBS and do not exhibit temporal overshoots that also reduce Kerr effects. The developed set-ups are used to check the reduction of the backward stimulated Brillouin scattering and they allow measuring with accuracy the rear surface damage of thick fused silica optics.

Sharing methodology: a worked example of theoretical integration with qualitative data to clarify practical understanding of learning and generate new theoretical development.

PubMed

Yardley, Sarah; Brosnan, Caragh; Richardson, Jane

2013-01-01

Theoretical integration is a necessary element of study design if clarification of experiential learning is to be achieved. There are few published examples demonstrating how this can be achieved. This methodological article provides a worked example of research methodology that achieved clarification of authentic early experiences (AEEs) through a bi-directional approach to theory and data. Bi-directional refers to our simultaneous use of theory to guide and interrogate empirical data and the use of empirical data to refine theory. We explain the five steps of our methodological approach: (1) understanding the context; (2) critique on existing applications of socio-cultural models to inform study design; (3) data generation; (4) analysis and interpretation and (5) theoretical development through a novel application of Metis. These steps resulted in understanding of how and why different outcomes arose from students participating in AEE. Our approach offers a mechanism for clarification without which evidence-based effective ways to maximise constructive learning cannot be developed. In our example it also contributed to greater theoretical understanding of the influence of social interactions. By sharing this example of research undertaken to develop both theory and educational practice we hope to assist others seeking to conduct similar research.

A Mathematical Model for the Middle Ear Ventilation

NASA Astrophysics Data System (ADS)

Molnárka, G.; Miletics, E. M.; Fücsek, M.

2008-09-01

The otitis media is one of the mostly existing illness for the children, therefore investigation of the human middle ear ventilation is an actual problem. In earlier investigations both experimental and theoretical approach one can find in ([l]-[3]). Here we give a new mathematical and computer model to simulate this ventilation process. This model able to describe the diffusion and flow processes simultaneously, therefore it gives more precise results than earlier models did. The article contains the mathematical model and some results of the simulation.

On the Hilbert-Huang Transform Theoretical Foundation

NASA Technical Reports Server (NTRS)

Kizhner, Semion; Blank, Karin; Huang, Norden E.

2004-01-01

The Hilbert-Huang Transform [HHT] is a novel empirical method for spectrum analysis of non-linear and non-stationary signals. The HHT is a recent development and much remains to be done to establish the theoretical foundation of the HHT algorithms. This paper develops the theoretical foundation for the convergence of the HHT sifting algorithm and it proves that the finest spectrum scale will always be the first generated by the HHT Empirical Mode Decomposition (EMD) algorithm. The theoretical foundation for cutting an extrema data points set into two parts is also developed. This then allows parallel signal processing for the HHT computationally complex sifting algorithm and its optimization in hardware.

Assessment of risk factors for earlier onset of sporadic Alzheimer's disease dementia.

PubMed

de Oliveira, Fabricio Ferreira; Bertolucci, Paulo Henrique Ferreira; Chen, Elizabeth Suchi; Smith, Marilia Cardoso

2014-01-01

Pharmacological treatment has mild effects for patients with Alzheimer's disease dementia (AD); therefore, the search for modifiable risk factors is an important challenge. Though risk factors for AD are widely recognized, elements that influence the time of dementia onset have not been comprehensively reported. We aimed to investigate which risk factors might be related to the age of onset of AD in a sample of patients with highly variable educational levels, taking into account the Framingham risk scoring as the sole measure of vascular risk. We included 209 consecutive late-onset AD patients to find out which factors among educational levels, coronary heart disease risk estimated by way of Framingham risk scores, history of head trauma or depression, surgical procedures under general anesthesia, family history of neurodegenerative diseases, gender, marital status and APOE haplotypes might be related to the age of dementia onset in this sample of patients with low mean schooling. Mean age of AD onset was 73.38±6.5 years old, unaffected by schooling or family history of neurodegenerative diseases. Patients who were APOE-ε4 carriers, married, or with history of depression, had earlier onset of AD, particularly when they were women. Coronary heart disease risk was marginally significant for later onset of AD. APOE haplotypes, marital status and history of depression were the most important factors to influence the age of AD onset in this sample. While midlife cerebrovascular risk factors may increase incidence of AD, they may lead to later dementia onset when present in late life.

Synthesis, Characterization, and Theoretical Considerations of 1,2-bis(oxyamino)ethane Salts

NASA Technical Reports Server (NTRS)

Crake, Greg; Hawkins, Tom; Hall, Leslie; Tollison, Kerri; Brand, Adam

2003-01-01

The synthesis, characterization, theoretical calculations, and safety studies of energetic salts of 1,2- bis(oxyamino) ethane, (H2N-O-CH2-CH2-O-NH2), were carried out. The salts were characterized by vibrational (infrared, Raman), multinuclear nmr studies (1H, 13C), differential scanning calorimetry (DSC); elemental analysis; and initial safety testing (impact and friction sensitivity) . Theoretical calculations on the neutral, monoprotonated, and doubly protonated species of ethylene bisoxyamine were carried out using xxxx level of theory for the lowest energy structure and these theoretical results compared with the experimentally observed bond distances and vibrational (ir, Raman) frequency values. The single crystal X-ray diffraction study was carried out on the mono-perchlorate salt revealing a high degree of hydrogen bonding with an unexpected structure.

Game theoretic power allocation and waveform selection for satellite communications

NASA Astrophysics Data System (ADS)

Shu, Zhihui; Wang, Gang; Tian, Xin; Shen, Dan; Pham, Khanh; Blasch, Erik; Chen, Genshe

2015-05-01

Game theory is a useful method to model interactions between agents with conflicting interests. In this paper, we set up a Game Theoretic Model for Satellite Communications (SATCOM) to solve the interaction between the transmission pair (blue side) and the jammer (red side) to reach a Nash Equilibrium (NE). First, the IFT Game Application Model (iGAM) for SATCOM is formulated to improve the utility of the transmission pair while considering the interference from a jammer. Specifically, in our framework, the frame error rate performance of different modulation and coding schemes is used in the game theoretic solution. Next, the game theoretic analysis shows that the transmission pair can choose the optimal waveform and power given the received power from the jammer. We also describe how the jammer chooses the optimal power given the waveform and power allocation from the transmission pair. Finally, simulations are implemented for the iGAM and the simulation results show the effectiveness of the SATCOM power allocation, waveform selection scheme, and jamming mitigation.

Theoretical development and first-principles analysis of strongly correlated systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chen

A variety of quantum many-body methods have been developed for studying the strongly correlated electron systems. We have also proposed a computationally efficient and accurate approach, named the correlation matrix renormalization (CMR) method, to address the challenges. The initial implementation of the CMR method is designed for molecules which have theoretical advantages, including small size of system, manifest mechanism and strongly correlation effect such as bond breaking process. The theoretic development and benchmark tests of the CMR method are included in this thesis. Meanwhile, ground state total energy is the most important property of electronic calculations. We also investigated anmore » alternative approach to calculate the total energy, and extended this method for magnetic anisotropy energy (MAE) of ferromagnetic materials. In addition, another theoretical tool, dynamical mean- field theory (DMFT) on top of the DFT , has also been used in electronic structure calculations for an Iridium oxide to study the phase transition, which results from an interplay of the d electrons' internal degrees of freedom.« less

Theoretical and experimental research on diversity reception technology in NLOS UV communication system.

PubMed

Han, Dahai; Liu, Yile; Zhang, Kai; Luo, Pengfei; Zhang, Min

2012-07-02

Diversity reception technology is introduced into ultraviolet communication area in this article with theory analysis and practical experiment. The idea of diversity reception was known as a critical effective method in wireless communication area that improves the Gain significantly especially for the multi-scattering channel. A theoretical modeling and simulation method are proposed to depict the principle and feasibility of diversity reception adopted in UV communication. Besides, an experimental test-bed using ultraviolet LED and dual receiver of photomultiplier tube is setup to characterize the effects of diversity receiving in non-line-of-sight (NLOS) ultraviolet communication system. The experiment results are compared with the theoretical ones to verify the accuracy of theoretical modeling and the effect of diversity reception. Equal gain combining (EGC) method was adopted as the diversity mechanism in this paper. The research results of theory and experiment provide insight into the channel characteristics and achievable capabilities of ultraviolet communication system with diversity receiving method.

Physical Violence between Siblings: A Theoretical and Empirical Analysis

ERIC Educational Resources Information Center

Hoffman, Kristi L.; Kiecolt, K. Jill; Edwards, John N.

2005-01-01

This study develops and tests a theoretical model to explain sibling violence based on the feminist, conflict, and social learning theoretical perspectives and research in psychology and sociology. A multivariate analysis of data from 651 young adults generally supports hypotheses from all three theoretical perspectives. Males with brothers have…

Theoretical and experimental research on laser-beam homogenization based on metal gauze

NASA Astrophysics Data System (ADS)

Liu, Libao; Zhang, Shanshan; Wang, Ling; Zhang, Yanchao; Tian, Zhaoshuo

2018-03-01

Method of homogenization of CO2 laser heating by means of metal gauze is researched theoretically and experimentally. Distribution of light-field of expanded beam passing through metal gauze was numerically calculated with diffractive optical theory and the conclusion is that method is effective, with comparing the results to the situation without metal gauze. Experimentally, using the 30W DC discharge laser as source and enlarging beam by concave lens, with and without metal gauze, beam intensity distributions in thermal paper were compared, meanwhile the experiments based on thermal imager were performed. The experimental result was compatible with theoretical calculation, and all these show that the homogeneity of CO2 laser heating could be enhanced by metal gauze.

Polarimetric Intensity Parameterization of Radar and Other Remote Sensing Sources for Advanced Exploitation and Data Fusion: Theory

DTIC Science & Technology

2008-10-01

is theoretically similar to the concept of “partial or compact polarimetry”, yields comparable results to full or quadrature-polarized systems by...to the emerging “compact polarimetry” methodology [9]-[13] that exploits scattering system response to an incomplete set of input EM field components...a scattering operator or matrix. Although as theoretically discussed earlier, performance of such fully-polarized radar system (i.e., quadrature

High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: Part 1, data analysis and results

NASA Astrophysics Data System (ADS)

Erskine, David J.; Edelstein, Jerry; Wishnow, Edward H.; Sirk, Martin; Muirhead, Philip S.; Muterspaugh, Matthew W.; Lloyd, James P.; Ishikawa, Yuzo; McDonald, Eliza A.; Shourt, William V.; Vanderburg, Andrew M.

2016-04-01

High-resolution broadband spectroscopy at near-infrared wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar. Observations of stars were performed with the "TEDI" interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec near-infrared echelle spectrograph. These are the first multidelay EDI demonstrations on starlight, as earlier measurements used a single delay or laboratory sources. We demonstrate very high (10×) resolution boost, from original 2700 to 27,000 with current set of delays (up to 3 cm), well beyond the classical limits enforced by the slit width and detector pixel Nyquist limit. Significantly, the EDI used with multiple delays rather than a single delay as used previously yields an order of magnitude or more improvement in the stability against native spectrograph point spread function (PSF) drifts along the dispersion direction. We observe a dramatic (20×) reduction in sensitivity to PSF shift using our standard processing. A recently realized method of further reducing the PSF shift sensitivity to zero is described theoretically and demonstrated in a simple simulation which produces a 350× times reduction. We demonstrate superb rejection of fixed pattern noise due to bad detector pixels-EDI only responds to changes in pixel intensity synchronous to applied dithering. This part 1 describes data analysis, results, and instrument noise. A section on theoretical photon limited sensitivity is in a companion paper, part 2.

Net motion of acoustically levitating nano-particles: A theoretical analysis

NASA Astrophysics Data System (ADS)

Lippera, Kevin; Dauchot, Olivier; Benzaquen, Michael; Gulliver-LadHyX Collaboration

2017-11-01

A particle 2D-trapped in the nodal planed of a standing acoustic wave is prone to acoustic-phoretic motion as soon as its shape breaks polar or chiral symmetry. such a setup constitues an ideal system to study boundaryless 2D collective behavior with purely hydrodynamic long range interactions. Recent studies have indeed shown that quasi-spherical particles may undergo net propulsion, a feature partially understood theoretically in the particular case of infinite viscous boundary layers. We here extend the theoretical results of to any boundary layer thickness, by that meeting typical experimental conditions. In addition, we propose an explanation for the net spinning of the trapped particles, as observed in experiments.

Gyrokinetic micro-turbulence simulations on the NERSC 16-way SMP IBM SP computer: experiences and performance results

NASA Astrophysics Data System (ADS)

Ethier, Stephane; Lin, Zhihong

2001-10-01

Earlier this year, the National Energy Research Scientific Computing center (NERSC) took delivery of the second most powerful computer in the world. With its 2,528 processors running at a peak performance of 1.5 GFlops, this IBM SP machine has a theoretical performance of almost 3.8 TFlops. To efficiently harness such computing power in one single code is not an easy task and requires a good knowledge of the computer's architecture. Here we present the steps that we followed to improve our gyrokinetic micro-turbulence code GTC in order to take advantage of the new 16-way shared memory nodes of the NERSC IBM SP. Performance results are shown as well as details about the improved mixed-mode MPI-OpenMP model that we use. The enhancements to the code allowed us to tackle much bigger problem sizes, getting closer to our goal of simulating an ITER-size tokamak with both kinetic ions and electrons.(This work is supported by DOE Contract No. DE-AC02-76CH03073 (PPPL), and in part by the DOE Fusion SciDAC Project.)

Theoretical dissociation energies for ionic molecules

NASA Technical Reports Server (NTRS)

Langhoff, S. R.; Bauschlicher, C. W., Jr.; Partridge, H.

1986-01-01

Ab initio calculations at the self-consistent-field and singles plus doubles configuration-interaction level are used to determine accurate spectroscopic parameters for most of the alkali and alkaline-earth fluorides, chlorides, oxides, sulfides, hydroxides, and isocyanides. Numerical Hartree-Fock (NHF) calculations are performed on selected systems to ensure that the extended Slater basis sets employed for the diatomic systems are near the Hartree-Fock limit. Extended Gaussian basis sets of at least triple-zeta plus double polarization equality are employed for the triatomic system. With this model, correlation effects are relatively small, but invariably increase the theoretical dissociation energies. The importance of correlating the electrons on both the anion and the metal is discussed. The theoretical dissociation energies are critically compared with the literature to rule out disparate experimental values. Theoretical (sup 2)Pi - (sup 2)Sigma (sup +) energy separations are presented for the alkali oxides and sulfides.

Comparison of experimental with theoretical total-pressure loss in parallel-walled turbojet combustors

NASA Technical Reports Server (NTRS)

Dittrich, Ralph T

1957-01-01

An experimental investigation of combustor total-pressure loss was undertaken to confirm previous theoretical analyses of effects of geometric and flow variables and of heat addition. The results indicate that a reasonable estimate of cold-flow total-pressure-loss coefficient may be obtained from the theoretical analyses. Calculated total-pressure loss due to heat addition agreed with experimental data only when there was no flame ejection from the liner at the upstream air-entry holes.

Measuring Theoretical Orientations of Counselor Trainees in Turkey: The Role of Personal and Professional Variables

ERIC Educational Resources Information Center

Demir, Ilkay; Gazioglu, Esra Ismen

2017-01-01

The first aim of this study was to explore the reliability and validity of the Turkish version of the Theoretical Orientation Profile Scale-Revised, and the second aim was to understand the relative influence of personal and professional variables on the choice of a guiding theoretical orientation among Turkish counselor trainees. Results showed…

Elucidating Grinding Mechanism by Theoretical and Experimental Investigations

PubMed Central

Kubo, Akihiko; Chowdhury, M. A. K.

2018-01-01

Grinding is one of the essential manufacturing processes for producing brittle or hard materials-based precision parts (e.g., optical lenses). In grinding, a grinding wheel removes the desired amount of material by passing the same area on the workpiece surface multiple times. How the topography of a workpiece surface evolves with these passes is thus an important research issue, which has not yet been addressed elaborately. The present paper tackles this issue from both the theoretical and the experimental points of view. In particular, this paper presents the results of experimental and theoretical investigations on the multi-pass surface grinding operations where the workpiece surface is made of glass and the grinding wheel consists of cBN abrasive grains. Both investigations confirm that a great deal of stochasticity is involved in the grinding mechanism, and the complexity of the workpiece surface gradually increases along with the number of passes. PMID:29425160

What Does (and Doesn't) Make Analogical Problem Solving Easy? A Complexity-Theoretic Perspective

ERIC Educational Resources Information Center

Wareham, Todd; Evans, Patricia; van Rooij, Iris

2011-01-01

Solving new problems can be made easier if one can build on experiences with other problems one has already successfully solved. The ability to exploit earlier problem-solving experiences in solving new problems seems to require several cognitive sub-abilities. Minimally, one needs to be able to retrieve relevant knowledge of earlier solved…

Earlier reperfusion in patients with ST-elevation Myocardial infarction by use of helicopter

PubMed Central

2012-01-01

Background In patients with ST-elevation myocardial infarction (STEMI) reperfusion therapy should be initiated as soon as possible. This study evaluated whether use of a helicopter for transportation of patients is associated with earlier initiation of reperfusion therapy. Material and methods A prospective study was conducted, including patients with STEMI and symptom duration less than 12 hours, who had primary percutaneous coronary intervention (PPCI) performed at Aarhus University Hospital in Skejby. Patients with a health care system delay (time from emergency call to first coronary intervention) of more than 360 minutes were excluded. The study period ran from 1.1.2011 until 31.12.2011. A Western Denmark Helicopter Emergency Medical Service (HEMS) project was initiated 1.6.2011 for transportation of patients with time-critical illnesses, including STEMI. Results The study population comprised 398 patients, of whom 376 were transported by ambulance Emergency Medical Service (EMS) and 22 by HEMS. Field-triage directly to the PCI-center was used in 338 of patients. The median system delay was 94 minutes among those field-triaged, and 168 minutes among those initially admitted to a local hospital. Patients transported by EMS and field-triaged were stratified into four groups according to transport distance from the scene of event to the PCI-center: ≤25 km., 26–50 km., 51–75 km. and > 75 km. For these groups, the median system delay was 78, 89, 99, and 141 minutes. Among patients transported by HEMS and field-triaged the estimated median transport distance by ground transportation was 115 km, and the observed system delay was 107 minutes. Based on second order polynomial regression, it was estimated that patients with a transport distance of >60 km to the PCI-center may benefit from helicopter transportation, and that transportation by helicopter is associated with a system delay of less than 120 minutes even at a transport distance up to 150 km

A Detection-Theoretic Model of Echo Inhibition

ERIC Educational Resources Information Center

Saberi, Kourosh; Petrosyan, Agavni

2004-01-01

A detection-theoretic analysis of the auditory localization of dual-impulse stimuli is described, and a model for the processing of spatial cues in the echo pulse is developed. Although for over 50 years "echo suppression" has been the topic of intense theoretical and empirical study within the hearing sciences, only a rudimentary understanding of…

Engaging with Theoretical Diffraction in Teacher Education

ERIC Educational Resources Information Center

Lanas, Maija; Rautio, Pauliina; Koskela, Anne; Kinnunen, Susanna; Viljamaa, Elina; Juutinen, Jaana

2017-01-01

This article presents a study in which we began with a question "how to teach theoretical reflectivity in teacher education," and ended with a sentence "there is theoretical diffraction in teacher education." The research presented in this paper took place in the context of a university course in which we have been involved for…

Dancing with data: an example of acquiring theoretical sensitivity in a grounded theory study.

PubMed

Hoare, Karen J; Mills, Jane; Francis, Karen

2012-06-01

Glaser suggested that the conceptual route from data collection to a grounded theory is a set of double back steps. The route forward inevitably results in the analyst stepping back. Additionally sidestepping through, leading participants down lines of inquiry and following data threads with other participants, is also characteristic of acquiring theoretical sensitivity, a key concept in grounded theory. Other ways of acquiring theoretical sensitivity comprise: reading the literature, open coding, category building, reflecting in memos followed by doubling back on data collection once further lines of inquiry are opened up. This paper describes how we 'danced with data' in pursuit of heightened theoretical sensitivity in a grounded theory study of information use by nurses working in general practice in New Zealand. Providing an example of how analytical tools are employed to theoretically sample emerging concepts. © 2012 Blackwell Publishing Asia Pty Ltd.

Theoretical prediction of nuclear magnetic shieldings and indirect spin-spin coupling constants in 1,1-, cis-, and trans-1,2-difluoroethylenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nozirov, Farhod, E-mail: teobaldk@gmail.com, E-mail: farhod.nozirov@gmail.com; Stachów, Michał, E-mail: michal.stachow@gmail.com; Kupka, Teobald, E-mail: teobaldk@gmail.com, E-mail: farhod.nozirov@gmail.com

2014-04-14

A theoretical prediction of nuclear magnetic shieldings and indirect spin-spin coupling constants in 1,1-, cis- and trans-1,2-difluoroethylenes is reported. The results obtained using density functional theory (DFT) combined with large basis sets and gauge-independent atomic orbital calculations were critically compared with experiment and conventional, higher level correlated electronic structure methods. Accurate structural, vibrational, and NMR parameters of difluoroethylenes were obtained using several density functionals combined with dedicated basis sets. B3LYP/6-311++G(3df,2pd) optimized structures of difluoroethylenes closely reproduced experimental geometries and earlier reported benchmark coupled cluster results, while BLYP/6-311++G(3df,2pd) produced accurate harmonic vibrational frequencies. The most accurate vibrations were obtained using B3LYP/6-311++G(3df,2pd)more » with correction for anharmonicity. Becke half and half (BHandH) density functional predicted more accurate {sup 19}F isotropic shieldings and van Voorhis and Scuseria's τ-dependent gradient-corrected correlation functional yielded better carbon shieldings than B3LYP. A surprisingly good performance of Hartree-Fock (HF) method in predicting nuclear shieldings in these molecules was observed. Inclusion of zero-point vibrational correction markedly improved agreement with experiment for nuclear shieldings calculated by HF, MP2, CCSD, and CCSD(T) methods but worsened the DFT results. The threefold improvement in accuracy when predicting {sup 2}J(FF) in 1,1-difluoroethylene for BHandH density functional compared to B3LYP was observed (the deviations from experiment were −46 vs. −115 Hz)« less

A Theoretical Framework towards Understanding of Emotional and Behavioural Difficulties

ERIC Educational Resources Information Center

Poulou, Maria S.

2014-01-01

Children's emotional and behavioural difficulties are the result of multiple individual, social and contextual factors working in concert. The current paper proposes a theoretical framework to interpret students' emotional and behavioural difficulties in schools, by taking into consideration teacher-student relationships, students'…

Individual behavioral phenotypes: an integrative meta-theoretical framework. Why "behavioral syndromes" are not analogs of "personality".

PubMed

Uher, Jana

2011-09-01

Animal researchers are increasingly interested in individual differences in behavior. Their interpretation as meaningful differences in behavioral strategies stable over time and across contexts, adaptive, heritable, and acted upon by natural selection has triggered new theoretical developments. However, the analytical approaches used to explore behavioral data still address population-level phenomena, and statistical methods suitable to analyze individual behavior are rarely applied. I discuss fundamental investigative principles and analytical approaches to explore whether, in what ways, and under which conditions individual behavioral differences are actually meaningful. I elaborate the meta-theoretical ideas underlying common theoretical concepts and integrate them into an overarching meta-theoretical and methodological framework. This unravels commonalities and differences, and shows that assumptions of analogy to concepts of human personality are not always warranted and that some theoretical developments may be based on methodological artifacts. Yet, my results also highlight possible directions for new theoretical developments in animal behavior research. Copyright © 2011 Wiley Periodicals, Inc.

Validation of the theoretical domains framework for use in behaviour change and implementation research

PubMed Central

2012-01-01

Background An integrative theoretical framework, developed for cross-disciplinary implementation and other behaviour change research, has been applied across a wide range of clinical situations. This study tests the validity of this framework. Methods Validity was investigated by behavioural experts sorting 112 unique theoretical constructs using closed and open sort tasks. The extent of replication was tested by Discriminant Content Validation and Fuzzy Cluster Analysis. Results There was good support for a refinement of the framework comprising 14 domains of theoretical constructs (average silhouette value 0.29): ‘Knowledge’, ‘Skills’, ‘Social/Professional Role and Identity’, ‘Beliefs about Capabilities’, ‘Optimism’, ‘Beliefs about Consequences’, ‘Reinforcement’, ‘Intentions’, ‘Goals’, ‘Memory, Attention and Decision Processes’, ‘Environmental Context and Resources’, ‘Social Influences’, ‘Emotions’, and ‘Behavioural Regulation’. Conclusions The refined Theoretical Domains Framework has a strengthened empirical base and provides a method for theoretically assessing implementation problems, as well as professional and other health-related behaviours as a basis for intervention development. PMID:22530986

Comparing geophysical measurements to theoretical estimates for soil mixtures at low pressures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wildenschild, D; Berge, P A; Berryman, K G

1999-01-15

The authors obtained good estimates of measured velocities of sand-peat samples at low pressures by using a theoretical method, the self-consistent theory of Berryman (1980), using sand and porous peat to represent the microstructure of the mixture. They were unable to obtain useful estimates with several other theoretical approaches, because the properties of the quartz, air and peat components of the samples vary over several orders of magnitude. Methods that are useful for consolidated rock cannot be applied directly to unconsolidated materials. Instead, careful consideration of microstructure is necessary to adapt the methods successfully. Future work includes comparison of themore » measured velocity values to additional theoretical estimates, investigation of Vp/Vs ratios and wave amplitudes, as well as modeling of dry and saturated sand-clay mixtures (e.g., Bonner et al., 1997, 1998). The results suggest that field data can be interpreted by comparing laboratory measurements of soil velocities to theoretical estimates of velocities in order to establish a systematic method for predicting velocities for a full range of sand-organic material mixtures at various pressures. Once the theoretical relationship is obtained, it can be used to estimate the soil composition at various depths from field measurements of seismic velocities. Additional refining of the method for relating velocities to soil characteristics is useful for development inversion algorithms.« less

Quantifying heterogeneity attributable to polythetic diagnostic criteria: theoretical framework and empirical application.

PubMed

Olbert, Charles M; Gala, Gary J; Tupler, Larry A

2014-05-01

Heterogeneity within psychiatric disorders is both theoretically and practically problematic: For many disorders, it is possible for 2 individuals to share very few or even no symptoms in common yet share the same diagnosis. Polythetic diagnostic criteria have long been recognized to contribute to this heterogeneity, yet no unified theoretical understanding of the coherence of symptom criteria sets currently exists. A general framework for analyzing the logical and mathematical structure, coherence, and diversity of Diagnostic and Statistical Manual diagnostic categories (DSM-5 and DSM-IV-TR) is proposed, drawing from combinatorial mathematics, set theory, and information theory. Theoretical application of this framework to 18 diagnostic categories indicates that in most categories, 2 individuals with the same diagnosis may share no symptoms in common, and that any 2 theoretically possible symptom combinations will share on average less than half their symptoms. Application of this framework to 2 large empirical datasets indicates that patients who meet symptom criteria for major depressive disorder and posttraumatic stress disorder tend to share approximately three-fifths of symptoms in common. For both disorders in each of the datasets, pairs of individuals who shared no common symptoms were observed. Any 2 individuals with either diagnosis were unlikely to exhibit identical symptomatology. The theoretical and empirical results stemming from this approach have substantive implications for etiological research into, and measurement of, psychiatric disorders.

Theoretical magnetograms based on quantitative simulation of a magnetospheric substorm

NASA Technical Reports Server (NTRS)

Chen, C.-K.; Wolf, R. A.; Karty, J. L.; Harel, M.

1982-01-01

Substorm currents derived from the Rice University computer simulation of the September 19, 1976 substorm event are used to compute theoretical magnetograms as a function of universal time for various stations, integrating the Biot-Savart law over a maze of about 2700 wires and bands that carry the ring, Birkeland and horizontal ionospheric currents. A comparison of theoretical results with corresponding observations leads to a claim of general agreement, especially for stations at high and middle magnetic latitudes. Model results suggest that the ground magnetic field perturbations arise from complicated combinations of different kinds of currents, and that magnetic field disturbances due to different but related currents cancel each other out despite the inapplicability of Fukushima's (1973) theorem. It is also found that the dawn-dusk asymmetry in the horizontal magnetic field disturbance component at low latitudes is due to a net downward Birkeland current at noon, a net upward current at midnight, and, generally, antisunward-flowing electrojets.

Anxiety: towards a decision-theoretic perspective.

PubMed

Shechter, M; Zeidner, M

1990-05-01

This paper sets out to illustrate how anxiety may be incorporated into a formal decision theoretic utility model of choice, and to suggest several measurement procedures towards that end. The major propositions derived and posited in this paper lend considerable support to intuitive notions with respect to the effects of anxiety on human behaviour in risky decision situations. Namely, that the willingness of an individual to pay to reduce health risks (an economic indicator of individual welfare associated with reduced morbidity or increased longevity) tends to be positive and higher when anxiety is present than when it is not. The formal results of the analysis show that when psychological considerations are incorporated into a state-dependent utility model, the normative results customarily obtained concerning value-of-life need to be qualified.

Resistance to Fusarium verticillioides and fumonisin accumulation in maize inbred lines involves an earlier and enhanced expression of lipoxygenase (LOX) genes.

PubMed

Maschietto, Valentina; Marocco, Adriano; Malachova, Alexandra; Lanubile, Alessandra

2015-09-01

Fusarium verticillioides causes ear rot in maize and contaminates the kernels with the fumonisin mycotoxins. It is known that plant lipoxygenase (LOX)-derived oxylipins regulate defence against pathogens and that the host-pathogen lipid cross-talk influences the pathogenesis. The expression profiles of fifteen genes of the LOX pathway were studied in kernels of resistant and susceptible maize lines, grown in field condition, at 3, 7 and 14 days post inoculation (dpi) with F. verticillioides. Plant defence responses were correlated with the pathogen growth, the expression profiles of fungal FUM genes for fumonisin biosynthesis and fumonisin content in the kernels. The resistant genotype limited fungal growth and fumonisin accumulation between 7 and 14 dpi. Pathogen growth became exponential in the susceptible line after 7 dpi, in correspondence with massive transcription of FUM genes and fumonisins augmented exponentially at 14 dpi. LOX pathway genes resulted strongly induced after pathogen inoculation in the resistant line at 3 and 7 dpi, whilst in the susceptible line the induction was reduced or delayed at 14 dpi. In addition, all genes resulted overexpressed before infection in kernels of the resistant genotype already at 3 dpi. The results suggest that resistance in maize may depend on an earlier activation of LOX genes and genes for jasmonic acid biosynthesis. Copyright © 2015 Elsevier GmbH. All rights reserved.

Theoretical Problems in Materials Science

NASA Technical Reports Server (NTRS)

Langer, J. S.; Glicksman, M. E.

1985-01-01

Interactions between theoretical physics and material sciences to identify problems of common interest in which some of the powerful theoretical approaches developed for other branches of physics may be applied to problems in materials science are presented. A unique structure was identified in rapidly quenched Al-14% Mn. The material has long-range directed bonds with icosahedral symmetry which does not form a regular structure but instead forms an amorphous-like quasiperiodic structure. Finite volume fractions of second phase material is advanced and is coupled with nucleation theory to describe the formation and structure of precipitating phases in alloys. Application of the theory of pattern formation to the problem of dendrite formation is studied.

Reanalysis of the occurrence of back pain among construction workers: modelling for the interdependent effects of heavy physical work, earlier back accidents, and aging.

PubMed

Nurminen, M

1997-11-01

To re-examine the relation between heavy physical work and the occurrence of sciatic pain among construction workers reported previously to be absent in an epidemiological study. METHODS-Poisson log linear regression was used to model for the frequency of sciatic pain among concrete reinforcement workers and maintenance house painters with adjustment for the interactive effects of earlier back accidents and aging that modified the relation. Concrete reinforcement work not only had a direct effect on the frequency of sciatic pain, but it also contributed significantly to the risk indirectly through earlier back accidents. The risk of sciatic pain increased from age 25 to 54 in a different manner for a worker depending on his occupational group and record of back accidents. Epidemiological studies on low back pain need to be analysed with sound methodology. This is important in view of future meta-analyses that will be performed for the purpose of providing guidelines on the prevention of back disorders in heavy physical work.

Theoretical Studies of Strongly Interacting Fine Particle Systems

NASA Astrophysics Data System (ADS)

Fearon, Michael

Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.

Experimental and theoretical study on the structure and vibrational spectra of β-2-aminopyridinium dihydrogenphosphate

NASA Astrophysics Data System (ADS)

Çırak, Çağrı; Demir, Selçuk; Ucun, Fatih; Çubuk, Osman

2011-08-01

Experimental and theoretical vibrational spectra of β-2-aminopyridinium dihydrogenphosphate (β-2APDP) have been investigated. The FT-IR spectrum of β-2APDP was recorded in the region 4000-400 cm -1. The optimized molecular structure and theoretical vibrational frequencies of β-2APDP have been investigated using ab initio Hartree-Fock (HF) and density functional B3LYP method with 6-311++G(d,p) basis set. The optimized geometric parameters (bond lengths and bond angles) and theoretical frequencies have been compared with the corresponding experimental data and it is found that they agree well with each other. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Furthermore, the used scale factors were obtained from the ratio of the frequency values of the strongest peaks in the experimental and theoretical IR spectra. From the results it was concluded that the B3LYP method is superior to the HF method for the vibrational frequencies.

Complementary functions of the two brain hemispheres: comparisons with earlier conceptions and implications for individual and society.

PubMed

Zeier, H

1989-07-01

The concept of different functions for the left and right cerebral hemispheres coincides in an astonishing way with earlier philosophical and psychological work which divided the human mind into two complementary functions without having a neurophysiological explanation. Representative are the ideas of Fichte, Hegel and Jung. The latter postulated the two subsystems Ego and Self and associated the conscious functions of the Ego with the intellect, the capacity for rational thought, and the Self with the mind, which also includes the emotional feelings. For the harmonic development and self-realization of man the functions of both systems in complementary interaction are required. Therefore, the current overaccentuation of the intellect and of progress directed technical-scientific thinking should be corrected by making better use of the much neglected functions of the right hemisphere.

Releasing the Results of Investigations

DTIC Science & Technology

2010-03-01

allow for lessons to be learned. RELEASING THE RESULTS OF INVESTIGATIONS On December 21, 2009, Gilbert Arenas – star basketball player for the...joke.1 Earlier in the month Mr. Arenas and teammate Javaris Crittenton – with only two years of NBA experience – “got into an argument over a card...Senior military leaders are analogous to NBA stars as both sets of professionals have risen through the ranks above their peers; they’ve reached the

Physical and optical properties of DCJTB dye for OLED display applications: Experimental and theoretical investigation

NASA Astrophysics Data System (ADS)

Kurban, Mustafa; Gündüz, Bayram

2017-06-01

In this study, 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) was achieved using the experimental and theoretical studies. The electronic, optical and spectroscopic properties of DCJTB molecule were first investigated by performing experimental both solution and thin film techniques and then theoretical calculations. Theoretical results showed that one intense electronic transition is 505.26 nm a quite reasonable and agreement with the measured experimental data 505.00 and 503 nm with solution technique and film technique, respectively. Experimental and simple models were also taken into consideration to calculate the optical refractive index (n) of DCJTB molecule. The structural and electronic properties were next calculated using density functional theory (DFT) with B3LYP/6-311G (d, p) basis set. UV, FT-IR spectra characteristics and the electronic properties, such as frontier orbitals, and band gap energy (Eg) of DCJTB were also recorded time-dependent (TD) DFT approach. The theoretical Eg value were found to be 2.269 eV which is consistent with experimental results obtained from solution technique for THF solvent (2.155 eV) and literature (2.16 eV). The results herein obtained reveal that solution is simple, cost-efficient and safe for optoelectronic applications when compared with film technique.

One-dimensional barcode reading: an information theoretic approach

NASA Astrophysics Data System (ADS)

Houni, Karim; Sawaya, Wadih; Delignon, Yves

2008-03-01

In the convergence context of identification technology and information-data transmission, the barcode found its place as the simplest and the most pervasive solution for new uses, especially within mobile commerce, bringing youth to this long-lived technology. From a communication theory point of view, a barcode is a singular coding based on a graphical representation of the information to be transmitted. We present an information theoretic approach for 1D image-based barcode reading analysis. With a barcode facing the camera, distortions and acquisition are modeled as a communication channel. The performance of the system is evaluated by means of the average mutual information quantity. On the basis of this theoretical criterion for a reliable transmission, we introduce two new measures: the theoretical depth of field and the theoretical resolution. Simulations illustrate the gain of this approach.

One-dimensional barcode reading: an information theoretic approach.

PubMed

Houni, Karim; Sawaya, Wadih; Delignon, Yves

2008-03-10

In the convergence context of identification technology and information-data transmission, the barcode found its place as the simplest and the most pervasive solution for new uses, especially within mobile commerce, bringing youth to this long-lived technology. From a communication theory point of view, a barcode is a singular coding based on a graphical representation of the information to be transmitted. We present an information theoretic approach for 1D image-based barcode reading analysis. With a barcode facing the camera, distortions and acquisition are modeled as a communication channel. The performance of the system is evaluated by means of the average mutual information quantity. On the basis of this theoretical criterion for a reliable transmission, we introduce two new measures: the theoretical depth of field and the theoretical resolution. Simulations illustrate the gain of this approach.

Theories of behaviour change synthesised into a set of theoretical groupings: introducing a thematic series on the theoretical domains framework.

PubMed

Francis, Jill J; O'Connor, Denise; Curran, Janet

2012-04-24

Behaviour change is key to increasing the uptake of evidence into healthcare practice. Designing behaviour-change interventions first requires problem analysis, ideally informed by theory. Yet the large number of partly overlapping theories of behaviour makes it difficult to select the most appropriate theory. The need for an overarching theoretical framework of behaviour change was addressed in research in which 128 explanatory constructs from 33 theories of behaviour were identified and grouped. The resulting Theoretical Domains Framework (TDF) appears to be a helpful basis for investigating implementation problems. Research groups in several countries have conducted TDF-based studies. It seems timely to bring together the experience of these teams in a thematic series to demonstrate further applications and to report key developments. This overview article describes the TDF, provides a brief critique of the framework, and introduces this thematic series.In a brief review to assess the extent of TDF-based research, we identified 133 papers that cite the framework. Of these, 17 used the TDF as the basis for empirical studies to explore health professionals' behaviour. The identified papers provide evidence of the impact of the TDF on implementation research. Two major strengths of the framework are its theoretical coverage and its capacity to elicit beliefs that could signify key mediators of behaviour change. The TDF provides a useful conceptual basis for assessing implementation problems, designing interventions to enhance healthcare practice, and understanding behaviour-change processes. We discuss limitations and research challenges and introduce papers in this series.

Theories of behaviour change synthesised into a set of theoretical groupings: introducing a thematic series on the theoretical domains framework

PubMed Central

2012-01-01

Behaviour change is key to increasing the uptake of evidence into healthcare practice. Designing behaviour-change interventions first requires problem analysis, ideally informed by theory. Yet the large number of partly overlapping theories of behaviour makes it difficult to select the most appropriate theory. The need for an overarching theoretical framework of behaviour change was addressed in research in which 128 explanatory constructs from 33 theories of behaviour were identified and grouped. The resulting Theoretical Domains Framework (TDF) appears to be a helpful basis for investigating implementation problems. Research groups in several countries have conducted TDF-based studies. It seems timely to bring together the experience of these teams in a thematic series to demonstrate further applications and to report key developments. This overview article describes the TDF, provides a brief critique of the framework, and introduces this thematic series. In a brief review to assess the extent of TDF-based research, we identified 133 papers that cite the framework. Of these, 17 used the TDF as the basis for empirical studies to explore health professionals’ behaviour. The identified papers provide evidence of the impact of the TDF on implementation research. Two major strengths of the framework are its theoretical coverage and its capacity to elicit beliefs that could signify key mediators of behaviour change. The TDF provides a useful conceptual basis for assessing implementation problems, designing interventions to enhance healthcare practice, and understanding behaviour-change processes. We discuss limitations and research challenges and introduce papers in this series. PMID:22531601

Caprylate Salts Based on Amines as Volatile Corrosion Inhibitors for Metallic Zinc: Theoretical and Experimental Studies.

PubMed

Valente, Marco A G; Teixeira, Deiver A; Azevedo, David L; Feliciano, Gustavo T; Benedetti, Assis V; Fugivara, Cecílio S

2017-01-01

The interaction of volatile corrosion inhibitors (VCI), caprylate salt derivatives from amines, with zinc metallic surfaces is assessed by density functional theory (DFT) computer simulations, electrochemical impedance (EIS) measurements and humid chamber tests. The results obtained by the different methods were compared, and linear correlations were obtained between theoretical and experimental data. The correlations between experimental and theoretical results showed that the molecular size is the determining factor in the inhibition efficiency. The models used and experimental results indicated that dicyclohexylamine caprylate is the most efficient inhibitor.

Finite area combustor theoretical rocket performance

NASA Technical Reports Server (NTRS)

Gordon, Sanford; Mcbride, Bonnie J.

1988-01-01

Previous to this report, the computer program of NASA SP-273 and NASA TM-86885 was capable of calculating theoretical rocket performance based only on the assumption of an infinite area combustion chamber (IAC). An option was added to this program which now also permits the calculation of rocket performance based on the assumption of a finite area combustion chamber (FAC). In the FAC model, the combustion process in the cylindrical chamber is assumed to be adiabatic, but nonisentropic. This results in a stagnation pressure drop from the injector face to the end of the chamber and a lower calculated performance for the FAC model than the IAC model.

Theoretical Advanced Study Institute: 2014

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeGrand, Thomas

The Theoretical Advanced Study Institute (TASI) was held at the University of Colorado, Boulder, during June 2-27, 2014. The topic was "Journeys through the Precision Frontier: Amplitudes for Colliders." The organizers were Professors Lance Dixon (SLAC) and Frank Petriello (Northwestern and Argonne). There were fifty-one students. Nineteen lecturers gave sixty seventy-five minute lectures. A Proceedings was published. This TASI was unique for its large emphasis on methods for calculating amplitudes. This was embedded in a program describing recent theoretical and phenomenological developments in particle physics. Topics included introductions to the Standard Model, to QCD (both in a collider context andmore » on the lattice), effective field theories, Higgs physics, neutrino interactions, an introduction to experimental techniques, and cosmology.« less

Photonics and spectroscopy in nanojunctions: a theoretical insight

DOE PAGES

Galperin, Michael

2017-04-11

The progress of experimental techniques at the nanoscale in the last decade made optical measurements in current-carrying nanojunctions a reality, thus indicating the emergence of a new field of research coined optoelectronics. Optical spectroscopy of open nonequilibrium systems is a natural meeting point for (at least) two research areas: nonlinear optical spectroscopy and quantum transport, each with its own theoretical toolbox. We review recent progress in the field comparing theoretical treatments of optical response in nanojunctions as is accepted in nonlinear spectroscopy and quantum transport communities. A unified theoretical description of spectroscopy in nanojunctions is presented. Here, we argue thatmore » theoretical approaches of the quantum transport community (and in particular, the Green function based considerations) yield a convenient tool for optoelectronics when the radiation field is treated classically, and that differences between the toolboxes may become critical when studying the quantum radiation field in junctions.« less

A theoretical trombone

NASA Astrophysics Data System (ADS)

LoPresto, Michael C.

2014-09-01

What follows is a description of a theoretical model designed to calculate the playing frequencies of the musical pitches produced by a trombone. The model is based on quantitative treatments that demonstrate the effects of the flaring bell and cup-shaped mouthpiece sections on these frequencies and can be used to calculate frequencies that compare well to both the desired frequencies of the musical pitches and those actually played on a real trombone.

Theoretical Analysis and Design of Ultrathin Broadband Optically Transparent Microwave Metamaterial Absorbers

PubMed Central

Deng, Ruixiang; Li, Meiling; Muneer, Badar; Zhu, Qi; Shi, Zaiying; Song, Lixin; Zhang, Tao

2018-01-01

Optically Transparent Microwave Metamaterial Absorber (OTMMA) is of significant use in both civil and military field. In this paper, equivalent circuit model is adopted as springboard to navigate the design of OTMMA. The physical model and absorption mechanisms of ideal lightweight ultrathin OTMMA are comprehensively researched. Both the theoretical value of equivalent resistance and the quantitative relation between the equivalent inductance and equivalent capacitance are derived for design. Frequency-dependent characteristics of theoretical equivalent resistance are also investigated. Based on these theoretical works, an effective and controllable design approach is proposed. To validate the approach, a wideband OTMMA is designed, fabricated, analyzed and tested. The results reveal that high absorption more than 90% can be achieved in the whole 6~18 GHz band. The fabricated OTMMA also has an optical transparency up to 78% at 600 nm and is much thinner and lighter than its counterparts. PMID:29324686

Theoretical Analysis and Design of Ultrathin Broadband Optically Transparent Microwave Metamaterial Absorbers.

PubMed

Deng, Ruixiang; Li, Meiling; Muneer, Badar; Zhu, Qi; Shi, Zaiying; Song, Lixin; Zhang, Tao

2018-01-11

Optically Transparent Microwave Metamaterial Absorber (OTMMA) is of significant use in both civil and military field. In this paper, equivalent circuit model is adopted as springboard to navigate the design of OTMMA. The physical model and absorption mechanisms of ideal lightweight ultrathin OTMMA are comprehensively researched. Both the theoretical value of equivalent resistance and the quantitative relation between the equivalent inductance and equivalent capacitance are derived for design. Frequency-dependent characteristics of theoretical equivalent resistance are also investigated. Based on these theoretical works, an effective and controllable design approach is proposed. To validate the approach, a wideband OTMMA is designed, fabricated, analyzed and tested. The results reveal that high absorption more than 90% can be achieved in the whole 6~18 GHz band. The fabricated OTMMA also has an optical transparency up to 78% at 600 nm and is much thinner and lighter than its counterparts.

Theoretical and simulation analysis of piezoelectric liquid resistance captor filled with pipeline

NASA Astrophysics Data System (ADS)

Zheng, Li; Zhigang, Yang; Junwu, Kan; Lisheng; Bo, Yan; Dan, Lu

2018-03-01

This paper designs a kind of Piezoelectric liquid resistance capture energy device, by using the superposition theory of the sheet deformation, the calculation model of the displacement curve of the circular piezoelectric vibrator and the power generation capacity under the concentrated load is established. The results show that the radius ratio, thickness ratio and Young’s modulus of the circular piezoelectric vibrator have greater influence on the power generation capacity. When the material of piezoelectric oscillator is determined, the best radius ratio and thickness ratio make the power generation capacity the largest. Excessive or small radius ratio and thickness ratio will reduce the generating capacity and even generate zero power. In addition, the electromechanical equivalent model is established. Equivalent analysis is made by changing the circuit impedance. The results are consistent with the theoretical simulation results, indicating that the established circuit model can truly reflect the characteristics of the theoretical model.

Experimental and theoretical study on THz spectrum artesunate

NASA Astrophysics Data System (ADS)

Zhang, Ai-Bing; Kong, Ling-Gao; Wang, Shi-Jin; Li, Lei; Zheng, Xiang-Zhi

2008-10-01

Artesunate is a very effective drug to treat malaria. They are studied experimentally by Terahertz (THz) time-domain spectroscopy (THz-TDS), and the characteristic absorption spectra are obtained in the range of 0.2 to 2.6 THz. The vibrational frequencies are calculated using the density functional theory (DFT). Theoretical results show that 0.71, 1.94 and 2.46 THz are significant agreement with the experimental results in 0.87, 1.82 and 2.46THz, and identification of vibrational modes are given. The calculated results further confirm that the characteristic frequencies come from the collective vibrational modes. The results suggest that the use of the THz-TDS technique can be an effective way to inspect for Chinese medicine.

A Theoretical and Methodological Evaluation of Leadership Research.

ERIC Educational Resources Information Center

Lashbrook, Velma J.; Lashbrook, William B.

This paper isolates some of the strengths and weaknesses of leadership research by evaluating it from both a theoretical and methodological perspective. The seven theories or approaches examined are: great man, trait, situational, style, functional, social influence, and interaction positions. General theoretical, conceptual, and measurement…

Masculinities in Higher Education: Theoretical and Practical Considerations

ERIC Educational Resources Information Center

Laker, Jason A., Ed.; Davis, Tracy, Ed.

2011-01-01

"Masculinities in Higher Education" provides empirical evidence, theoretical support, and developmental interventions for educators working with college men both in and out of the classroom. The critical philosophical perspective of the text challenges the status-quo and offers theoretically sound educational strategies to successfully promote…

Theoretical models of parental HIV disclosure: a critical review.

PubMed

Qiao, Shan; Li, Xiaoming; Stanton, Bonita

2013-01-01

This study critically examined three major theoretical models related to parental HIV disclosure (i.e., the Four-Phase Model [FPM], the Disclosure Decision Making Model [DDMM], and the Disclosure Process Model [DPM]), and the existing studies that could provide empirical support to these models or their components. For each model, we briefly reviewed its theoretical background, described its components and/or mechanisms, and discussed its strengths and limitations. The existing empirical studies supported most theoretical components in these models. However, hypotheses related to the mechanisms proposed in the models have not yet tested due to a lack of empirical evidence. This study also synthesized alternative theoretical perspectives and new issues in disclosure research and clinical practice that may challenge the existing models. The current study underscores the importance of including components related to social and cultural contexts in theoretical frameworks, and calls for more adequately designed empirical studies in order to test and refine existing theories and to develop new ones.

Caprylate Salts Based on Amines as Volatile Corrosion Inhibitors for Metallic Zinc: Theoretical and Experimental Studies

PubMed Central

Valente, Marco A. G.; Teixeira, Deiver A.; Azevedo, David L.; Feliciano, Gustavo T.; Benedetti, Assis V.; Fugivara, Cecílio S.

2017-01-01

The interaction of volatile corrosion inhibitors (VCI), caprylate salt derivatives from amines, with zinc metallic surfaces is assessed by density functional theory (DFT) computer simulations, electrochemical impedance (EIS) measurements and humid chamber tests. The results obtained by the different methods were compared, and linear correlations were obtained between theoretical and experimental data. The correlations between experimental and theoretical results showed that the molecular size is the determining factor in the inhibition efficiency. The models used and experimental results indicated that dicyclohexylamine caprylate is the most efficient inhibitor. PMID:28620602

Theoretical and observational determinations of the ionization coefficient of meteors

NASA Astrophysics Data System (ADS)

Jones, William

1997-07-01

We examine the problem of the determination of the ionization coefficient beta from both the theoretical and observational points of view. In the past, theoretical evaluations of beta in terms of the relevant scattering cross-sections have used the Massey-Sida formula, which we show to give results which are plainly incorrect. We derive an integral equation for beta and compare the results of its application to copper and iron with laboratory simulations. Agreement for the variation of the ionization coefficient with velocity is good. The ionization coefficient has been determined observationally by Verniani & Hawkins from a comparison of radar and visual observations, employing the luminous efficiency tau also obtained observationally by Verniani. However, this determination of tau would appear to be invalidated by fragmentation. There is good evidence that the radiation of cometary meteors is dominated by that of iron in the visual range, and we have accordingly re-analysed the data of Verniani & Hawkins using the luminous efficiency of iron obtained in simulation experiments. However, it is not possible to choose an iron concentration which gives agreement between the determination of the ionization coefficient by this means and its determination from the theoretical equation in terms of either scattering coefficients or simulation methods. The observational ionization coefficients are much lower than predicted by the present theory and we provisionally explain this as a consequence of transfer of charge from the meteoric ion to a molecule of the air. It is now possible for the meteoric atom to be re-ionized, but it is also possible at sufficiently high initial line densities for significant dissociative recombination of the electrons and nitrogen or oxygen to take place. This recombination will not take place in meteor trains simulated in an ionization chamber. We thus conclude that the present theory is limited to faint radio meteors at lower velocities (v<~35

My Career as a Theoretical Physicist - So Far

NASA Astrophysics Data System (ADS)

Langer, J. S.

2017-03-01

Theoretical physics and the institutions that support it have changed greatly during my career. In this article, I recount some of my most memorable experiences as a physicist, first as a graduate student with Rudolf Peierls at the University of Birmingham in England and later as a colleague of Walter Kohn at the Institute for Theoretical Physics in Santa Barbara, California. I use this account to illustrate some of the changes that have occurred in my field and also as a rationale for asserting that theoretical physics has an increasingly vital role to play in modern science.

Theoretical modeling of critical temperature increase in metamaterial superconductors

NASA Astrophysics Data System (ADS)

Smolyaninov, Igor I.; Smolyaninova, Vera N.

2016-05-01

Recent experiments have demonstrated that the metamaterial approach is capable of a drastic increase of the critical temperature Tc of epsilon near zero (ENZ) metamaterial superconductors. For example, tripling of the critical temperature has been observed in Al -A l2O3 ENZ core-shell metamaterials. Here, we perform theoretical modeling of Tc increase in metamaterial superconductors based on the Maxwell-Garnett approximation of their dielectric response function. Good agreement is demonstrated between theoretical modeling and experimental results in both aluminum- and tin-based metamaterials. Taking advantage of the demonstrated success of this model, the critical temperature of hypothetic niobium-, Mg B2- , and H2S -based metamaterial superconductors is evaluated. The Mg B2 -based metamaterial superconductors are projected to reach the liquid nitrogen temperature range. In the case of a H2S -based metamaterial Tc appears to reach ˜250 K.

PREFACE: 1st International Workshop on Theoretical and Computational Physics: Condensed Matter, Soft Matter and Materials Physics & 38th National Conference on Theoretical Physics

NASA Astrophysics Data System (ADS)

2014-09-01

This volume contains selected papers presented at the 38th National Conference on Theoretical Physics (NCTP-38) and the 1st International Workshop on Theoretical and Computational Physics: Condensed Matter, Soft Matter and Materials Physics (IWTCP-1). Both the conference and the workshop were held from 29 July to 1 August 2013 in Pullman hotel, Da Nang, Vietnam. The IWTCP-1 was a new activity of the Vietnamese Theoretical Physics Society (VTPS) organized in association with the 38th National Conference on Theoretical Physics (NCTP-38), the most well-known annual scientific forum dedicated to the dissemination of the latest development in the field of theoretical physics within the country. The IWTCP-1 was also an External Activity of the Asia Pacific Center for Theoretical Physics (APCTP). The overriding goal of the IWTCP is to provide an international forum for scientists and engineers from academia to share ideas, problems and solution relating to the recent advances in theoretical physics as well as in computational physics. The main IWTCP motivation is to foster scientific exchanges between the Vietnamese theoretical and computational physics community and world-wide scientists as well as to promote high-standard level of research and education activities for young physicists in the country. About 110 participants coming from 10 countries participated in the conference and the workshop. 4 invited talks, 18 oral contributions and 46 posters were presented at the conference. In the workshop we had one keynote lecture and 9 invited talks presented by international experts in the fields of theoretical and computational physics, together with 14 oral and 33 poster contributions. The proceedings were edited by Nguyen Tri Lan, Trinh Xuan Hoang, and Nguyen Ai Viet. We would like to thank all invited speakers, participants and sponsors for making the conference and the workshop successful. Nguyen Ai Viet Chair of NCTP-38 and IWTCP-1

2011 Annual Survey of Journalism and Mass Communication Enrollments: Enrollments Decline, Reversing the Increase of a Year Earlier, and Suggesting Slow Growth for Future

ERIC Educational Resources Information Center

Becker, Lee B.; Vlad, Tudor; Kalpen, Konrad

2012-01-01

Enrollments in journalism and mass communication programs declined in the autumn of 2011, compared to a year earlier. Enrollments were down slightly at the senior and junior levels and substantially at the freshman level. Enrollment increased at the sophomore level. The majority of administrators say they have made curricular changes in the past…

Theoretical and experimental vibrational spectroscopy study on rotational isomer of 4-phenylbutylamine

NASA Astrophysics Data System (ADS)

Ünal, A.; Okur, M.

2017-02-01

The possible four stable rotational isomers of 4-phenylbutylamine (4PBA) molecule were experimentally and theoretically studied by vibrational spectroscopy. The FT-IR (4000-400 cm-1) and Raman (3700-60 cm-1) spectra of 4PBA were recorded at room temperature in liquid phase. The complete vibrational wavenumbers and corresponding vibrational assignments of 4PBA molecule were discussed assisted with B3LYP/6-311++G(d,p) level of theory along with scaled quantum mechanics force field (SQM-FF) method. Results from experimental and theoretical data the most stable form of 4PBA molecule was obtained.

Recent progress in the theoretical modelling of Cepheids and RR Lyrae stars

NASA Astrophysics Data System (ADS)

Marconi, Marcella

2017-09-01

Cepheids and RR Lyrae are among the most important primary distance indicators to calibrate the extragalactic distance ladder and excellent stellar population tracers, for Population I and Population II, respectively. In this paper I first mention some recent theoretical studies of Cepheids and RR Lyrae obtained with different theoretical tools. Then I focus the attention on new results based on nonlinear convective pulsation models in the context of some international projects, including VMC@VISTA and the Gaia collaboration. The open problems for both Cepheids and RR Lyrae are briefly discussed together with some challenging future application.

Bowel cancer screening is safe, detects earlier stage cancer and adenomas in 50% of cases: experience of the prevalent round of screening from two first wave centres in the North East of England.

PubMed

Rajasekhar, P T; Clifford, G M; Lee, T J W; Rutter, M D; Waddup, G; Ritchie, M; Nylander, D; Painter, J; Singh, J; Ward, I; Dempsey, N; Bowes, J; Handley, G; Henry, J; Rees, C J

2012-01-01

The NHS Bowel Cancer Screening Programme (BCSP) began roll-out in 2006 aiming to reduce cancer mortality through detection at an earlier stage. We report results from the prevalent round of screening at two first wave centres and compare with the UK pilot study. This is a service evaluation study. Data were collected prospectively for all individuals undergoing faecal occult blood testing (FOBt) and colonoscopy including: uptake and outcomes of FOBt, colonoscopic performance, findings, histological data and complications. Continuous data were compared using a two-tailed test of two proportions. The South of Tyne and Tees Bowel Cancer Screening centres. Participants of the BCSP. 1) Colonoscopy Quality Assurance and 2) Cancer stage shift. 195,772 individuals were invited to participate. Uptake was 54% and FOBt positivity 1.7%. 1524 underwent colonoscopy with caecal intubation in 1485 (97%). 180 (12%) cancers were detected. Dukes stages were: 76 (42%) A; 47 (26%) B; 47 (26%) C; 8 (4%) D and 2 (1%) unknown. This demonstrates a significantly earlier stage at diagnosis compared with data from 2867 non-screening detected cancers (p<0.001). Adenomas were detected in 758 (50%). One perforation occurred (0.07%) and two intermediate bleeds requiring transfusion only (0.12%). Both caecal intubation and adenoma detection were significantly higher than in the UK pilot study (p<0.001). The prevalent round of screening demonstrates a high adenoma and cancer detection rate and significantly earlier stage at diagnosis. Complications were few providing reassurance regarding safety. Efforts are required to improve uptake.

Assessing theoretical uncertainties in fission barriers of superheavy nuclei

DOE PAGES

Agbemava, S. E.; Afanasjev, A. V.; Ray, D.; ...

2017-05-26

Here, theoretical uncertainties in the predictions of inner fission barrier heights in superheavy elements have been investigated in a systematic way for a set of state-of-the-art covariant energy density functionals which represent major classes of the functionals used in covariant density functional theory. They differ in basic model assumptions and fitting protocols. Both systematic and statistical uncertainties have been quantified where the former turn out to be larger. Systematic uncertainties are substantial in superheavy elements and their behavior as a function of proton and neutron numbers contains a large random component. The benchmarking of the functionals to the experimental datamore » on fission barriers in the actinides allows to reduce the systematic theoretical uncertainties for the inner fission barriers of unknown superheavy elements. However, even then they on average increase on moving away from the region where benchmarking has been performed. In addition, a comparison with the results of non-relativistic approaches is performed in order to define full systematic theoretical uncertainties over the state-of-the-art models. Even for the models benchmarked in the actinides, the difference in the inner fission barrier height of some superheavy elements reaches $5-6$ MeV. This uncertainty in the fission barrier heights will translate into huge (many tens of the orders of magnitude) uncertainties in the spontaneous fission half-lives.« less

Awareness of Aging: Theoretical Considerations on an Emerging Concept

PubMed Central

Diehl, Manfred; Wahl, Hans-Werner; Barrett, Anne E.; Brothers, Allyson F.; Miche, Martina; Montepare, Joann M.; Westerhof, Gerben J.; Wurm, Susanne

2014-01-01

Humans are able to reflect on and interpret their own aging. Thus, as individuals grow older, calendar age may become increasingly a subjective variable. This theoretical paper proposes the concept of Awareness of Aging (AoA) as a superordinate construct that can serve an integrative function in developmental research on subjective aging. It is argued that the AoA construct can incorporate the theoretical components of other existing concepts by acknowledging that judgments of subjective aging tend to be made on an awareness continuum ranging from pre-conscious/implicit to conscious/explicit. We also argue that processes of AoA are inherently self-related processes and that AoA is a particular aspect of self-awareness that results in specific aging-related self-knowledge. Over time, aging individuals incorporate this self-knowledge into their self-concept and personal identity. We provide theoretical evidence showing that although all major theories of adult development and aging draw on phenomena related to AoA, the explicit incorporation of aging-related awareness processes has been missing. We also provide an overarching framework to illustrate in a heuristic way how AoA in combination and interaction with other influences affects developmental outcomes. Finally, we argue that attention to AoA-related processes has a number of societal and applied implications and thereby addresses issues of applied developmental psychology. PMID:24958998

Theoretical Grounding: The "Missing Link" in Suicide Research.

ERIC Educational Resources Information Center

Rogers, James R.

2001-01-01

Discusses the strengths and limitations of the current pragmatic focus of research in suicidology and presents an argument for theoretical grounding as a precursor for continued advancement in this area. Presents an existential-constructivist framework of "meaning creation" as a theoretical heuristic for understanding suicide. Outlines general…

Experimental and theoretical analysis for improved microscope design of optical projection tomographic microscopy.

PubMed

Coe, Ryan L; Seibel, Eric J

2013-09-01

We present theoretical and experimental results of axial displacement of objects relative to a fixed condenser focal plane (FP) in optical projection tomographic microscopy (OPTM). OPTM produces three-dimensional, reconstructed images of single cells from two-dimensional projections. The cell rotates in a microcapillary to acquire projections from different perspectives where the objective FP is scanned through the cell while the condenser FP remains fixed at the center of the microcapillary. This work uses a combination of experimental and theoretical methods to improve the OPTM instrument design.

MHD Energy Bypass Scramjet Performance with Real Gas Effects

NASA Technical Reports Server (NTRS)

Park, Chul; Mehta, Unmeel B.; Bogdanoff, David W.

2000-01-01

The theoretical performance of a scramjet propulsion system incorporating an magneto-hydro-dynamic (MHD) energy bypass scheme is calculated. The one-dimensional analysis developed earlier, in which the theoretical performance is calculated neglecting skin friction and using a sudden-freezing approximation for the nozzle flow, is modified to incorporate the method of Van Driest for turbulent skin friction and a finite-rate chemistry calculation in the nozzle. Unlike in the earlier design, in which four ramp compressions occurred in the pitch plane, in the present design the first two ramp compressions occur in the pitch plane and the next two compressions occur in the yaw plane. The results for the simplified design of a spaceliner show that (1) the present design produces higher specific impulses than the earlier design, (2) skin friction substantially reduces thrust and specific impulse, and (3) the specific impulse of the MHD-bypass system is still better than the non-MHD system and typical rocket over a narrow region of flight speeds and design parameters. Results suggest that the energy management with MHD principles offers the possibility of improving the performance of the scramjet. The technical issues needing further studies are identified.

A theoretical model describing the one-dimensional growth of single crystals on free sustained substrates

NASA Astrophysics Data System (ADS)

Ye, Ziran; Wang, Ke; Lu, Chenxi; Jin, Ying; Sui, Chenghua; Yan, Bo; Gao, Fan; Cai, Pinggen; Lv, Bin; Li, Yun; Chen, Naibo; Sun, Guofang; Xu, Fengyun; Ye, Gaoxiang

2018-03-01

We develop a theoretical model that interprets the growth mechanism of zinc (Zn) crystal nanorods on a liquid substrate by thermal evaporation. During deposition, Zn atoms diffuse randomly on an isotropic and quasi-free sustained substrate, the nucleation of the atoms results in the primary nanorod (or seed crystal) growth. Subsequently, a characteristic one-dimensional atomic aggregation is proposed, which leads to the accelerating growth of the crystal nanorod along its preferential growth direction until the growth terminates. The theoretical results are in good agreement with the experimental findings.

Theoretical and Computational Investigation of High-Brightness Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chiping

Theoretical and computational investigations of adiabatic thermal beams have been carried out in parameter regimes relevant to the development of advanced high-brightness, high-power accelerators for high-energy physics research and for various applications such as light sources. Most accelerator applications require high-brightness beams. This is true for high-energy accelerators such as linear colliders. It is also true for energy recovery linacs (ERLs) and free electron lasers (FELs) such as x-ray free electron lasers (XFELs). The breakthroughs and highlights in our research in the period from February 1, 2013 to November 30, 2013 were: a) Completion of a preliminary theoretical and computationalmore » study of adiabatic thermal Child-Langmuir flow (Mok, 2013); and b) Presentation of an invited paper entitled ?Adiabatic Thermal Beams in a Periodic Focusing Field? at Space Charge 2013 Workshop, CERN, April 16-19, 2013 (Chen, 2013). In this report, an introductory background for the research project is provided. Basic theory of adiabatic thermal Child-Langmuir flow is reviewed. Results of simulation studies of adiabatic thermal Child-Langmuir flows are discussed.« less

Effects of anisotropic interaction-induced properties of hydrogen-rare gas compounds on rototranslational Raman scattering spectra: Comprehensive theoretical and numerical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Głaz, Waldemar, E-mail: glaz@kielich.amu.edu.pl; Bancewicz, Tadeusz; Godet, Jean-Luc

2016-07-21

A comprehensive study is presented of many aspects of the depolarized anisotropic collision induced (CI) component of light scattered by weakly bound compounds composed of a dihydrogen molecule and a rare gas (Rg) atom, H{sub 2}–Rg. The work continues a series of earlier projects marking the revival of interest in linear light scattering following the development of new highly advanced tools of quantum chemistry and other theoretical, computational, and experimental means of spectral analyses. Sophisticated ab initio computing procedures are applied in order to obtain the anisotropic polarizability component’s dependence on the H{sub 2}–Rg geometry. These data are then usedmore » to evaluate the CI spectral lines for all types of Rg atoms ranging from He to Xe (Rn excluded). Evolution of the properties of CI spectra with growing polarizability/masses of the complexes studied is observed. Special attention is given to the heaviest, Kr and Xe based, scatterers. The influence of specific factors shaping the spectral lines (e.g., bound and metastable contribution, potential anisotropy) is discussed. Also the share of pressure broadened allowed rotational transitions in the overall spectral profile is taken into account and the extent to which it is separable from the pure CI contribution is discussed. We finish with a brief comparison between the obtained results and available experimental data.« less

Accurate Theoretical Predictions of the Properties of Energetic Materials

DTIC Science & Technology

2008-09-18

decomposition, Monte Carlo, molecular dynamics, supercritical fluids, solvation and separation, quantum Monte Carlo, potential energy surfaces, RDX , TNAZ...labs, who are contributing to the theoretical efforts, providing data for testing of the models, or aiding in the transition of the methods, models...and results to DoD applications. The major goals of the project are: • Models that describe phase transitions and chemical reactions in

Experimental and theoretical investigation of the temperature dependent electronic quenching of O(1D) atoms in collisions with Kr

NASA Astrophysics Data System (ADS)

Nuñez-Reyes, Dianailys; Kłos, Jacek; Alexander, Millard H.; Dagdigian, Paul J.; Hickson, Kevin M.

2018-03-01

The kinetics and dynamics of the collisional electronic quenching of O(1D) atoms by Kr have been investigated in a joint experimental and theoretical study. The kinetics of quenching were measured over the temperature range 50-296 K using the Laval nozzle method. O(1D) atoms were prepared by 266 nm photolysis of ozone, and the decay of the O(1D) concentration was monitored through vacuum ultraviolet fluorescence at 115.215 nm, from which the rate constant was determined. To interpret the experiments, a quantum close-coupling treatment of the quenching transition from the 1D state to the 3Pj fine-structure levels in collisions with Kr, and also Ar and Xe, was carried out. The relevant potential energy curves and spin-orbit coupling matrix elements were obtained in electronic structure calculations. We find reasonable agreement between computed temperature-dependent O(1D)-Rg (Rg = Ar, Kr, Xe) quenching rate constants and the present measurements for Kr and earlier measurements. In particular, the temperature dependence is well described.

Analysis of Implicit Uncertain Systems. Part 1: Theoretical Framework

DTIC Science & Technology

1994-12-07

Analysis of Implicit Uncertain Systems Part I: Theoretical Framework Fernando Paganini * John Doyle 1 December 7, 1994 Abst rac t This paper...Analysis of Implicit Uncertain Systems Part I: Theoretical Framework 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...model and a number of constraints relevant to the analysis problem under consideration. In Part I of this paper we propose a theoretical framework which

Physics of mind: Experimental confirmations of theoretical predictions.

PubMed

Schoeller, Félix; Perlovsky, Leonid; Arseniev, Dmitry

2018-02-02

What is common among Newtonian mechanics, statistical physics, thermodynamics, quantum physics, the theory of relativity, astrophysics and the theory of superstrings? All these areas of physics have in common a methodology, which is discussed in the first few lines of the review. Is a physics of the mind possible? Is it possible to describe how a mind adapts in real time to changes in the physical world through a theory based on a few basic laws? From perception and elementary cognition to emotions and abstract ideas allowing high-level cognition and executive functioning, at nearly all levels of study, the mind shows variability and uncertainties. Is it possible to turn psychology and neuroscience into so-called "hard" sciences? This review discusses several established first principles for the description of mind and their mathematical formulations. A mathematical model of mind is derived from these principles. This model includes mechanisms of instincts, emotions, behavior, cognition, concepts, language, intuitions, and imagination. We clarify fundamental notions such as the opposition between the conscious and the unconscious, the knowledge instinct and aesthetic emotions, as well as humans' universal abilities for symbols and meaning. In particular, the review discusses in length evolutionary and cognitive functions of aesthetic emotions and musical emotions. Several theoretical predictions are derived from the model, some of which have been experimentally confirmed. These empirical results are summarized and we introduce new theoretical developments. Several unsolved theoretical problems are proposed, as well as new experimental challenges for future research. Copyright © 2017. Published by Elsevier B.V.

Structural characterisation of some vanillic Mannich bases: Experimental and theoretical study

NASA Astrophysics Data System (ADS)

Petrović, Vladimir P.; Simijonović, Dušica; Novaković, Sladjana B.; Bogdanović, Goran A.; Marković, Svetlana; Petrović, Zorica D.

2015-10-01

In this paper, synthesis and structural determination of 2-[1-(N-4-fluorophenylamino)-1-(4-hydroxy-3-methoxyphenyl)]methylcyclohexanone (MB-F) is presented. To determine the structure of this new compound, IR and NMR spectral characterisation was performed experimentally and theoretically. Simulation of spectral data was carried out using three functionals: B3LYP, B3LYP-D2, and M06-2X. The results obtained for MB-F were compared to those attained for similar, known compound 2-[1-(N-phenylamino)-1-(4-hydroxy-3-methoxyphenyl)]methylcyclohexanone (MB-H), whose crystal structure is presented here. Taking into account all experimental and theoretical findings, the structure of MB-F was proposed.

A theoretical approach to dual practice regulations in the health sector.

PubMed

González, Paula; Macho-Stadler, Inés

2013-01-01

Internationally, there is wide cross-country heterogeneity in government responses to dual practice in the health sector. This paper provides a uniform theoretical framework to analyze and compare some of the most common regulations. We focus on three interventions: banning dual practice, offering rewarding contracts to public physicians, and limiting dual practice (including both limits to private earnings of dual providers and limits to involvement in private activities). An ancillary objective of the paper is to investigate whether regulations that are optimal for developed countries are adequate for developing countries as well. Our results offer theoretical support for the desirability of different regulations in different economic environments. Copyright © 2012 Elsevier B.V. All rights reserved.

Optimal information transfer in enzymatic networks: A field theoretic formulation

NASA Astrophysics Data System (ADS)

Samanta, Himadri S.; Hinczewski, Michael; Thirumalai, D.

2017-07-01

Signaling in enzymatic networks is typically triggered by environmental fluctuations, resulting in a series of stochastic chemical reactions, leading to corruption of the signal by noise. For example, information flow is initiated by binding of extracellular ligands to receptors, which is transmitted through a cascade involving kinase-phosphatase stochastic chemical reactions. For a class of such networks, we develop a general field-theoretic approach to calculate the error in signal transmission as a function of an appropriate control variable. Application of the theory to a simple push-pull network, a module in the kinase-phosphatase cascade, recovers the exact results for error in signal transmission previously obtained using umbral calculus [Hinczewski and Thirumalai, Phys. Rev. X 4, 041017 (2014), 10.1103/PhysRevX.4.041017]. We illustrate the generality of the theory by studying the minimal errors in noise reduction in a reaction cascade with two connected push-pull modules. Such a cascade behaves as an effective three-species network with a pseudointermediate. In this case, optimal information transfer, resulting in the smallest square of the error between the input and output, occurs with a time delay, which is given by the inverse of the decay rate of the pseudointermediate. Surprisingly, in these examples the minimum error computed using simulations that take nonlinearities and discrete nature of molecules into account coincides with the predictions of a linear theory. In contrast, there are substantial deviations between simulations and predictions of the linear theory in error in signal propagation in an enzymatic push-pull network for a certain range of parameters. Inclusion of second-order perturbative corrections shows that differences between simulations and theoretical predictions are minimized. Our study establishes that a field theoretic formulation of stochastic biological signaling offers a systematic way to understand error propagation in

Potential benefits of remote sensing: Theoretical framework and empirical estimate

NASA Technical Reports Server (NTRS)

Eisgruber, L. M.

1972-01-01

A theoretical framwork is outlined for estimating social returns from research and application of remote sensing. The approximate dollar magnitude is given of a particular application of remote sensing, namely estimates of corn production, soybeans, and wheat. Finally, some comments are made on the limitations of this procedure and on the implications of results.

Theoretical Astrophysics at Fermilab

NASA Technical Reports Server (NTRS)

2004-01-01

The Theoretical Astrophysics Group works on a broad range of topics ranging from string theory to data analysis in the Sloan Digital Sky Survey. The group is motivated by the belief that a deep understanding of fundamental physics is necessary to explain a wide variety of phenomena in the universe. During the three years 2001-2003 of our previous NASA grant, over 120 papers were written; ten of our postdocs went on to faculty positions; and we hosted or organized many workshops and conferences. Kolb and collaborators focused on the early universe, in particular and models and ramifications of the theory of inflation. They also studied models with extra dimensions, new types of dark matter, and the second order effects of super-horizon perturbations. S tebbins, Frieman, Hui, and Dodelson worked on phenomenological cosmology, extracting cosmological constraints from surveys such as the Sloan Digital Sky Survey. They also worked on theoretical topics such as weak lensing, reionization, and dark energy. This work has proved important to a number of experimental groups [including those at Fermilab] planning future observations. In general, the work of the Theoretical Astrophysics Group has served as a catalyst for experimental projects at Fennilab. An example of this is the Joint Dark Energy Mission. Fennilab is now a member of SNAP, and much of the work done here is by people formerly working on the accelerator. We have created an environment where many of these people made transition from physics to astronomy. We also worked on many other topics related to NASA s focus: cosmic rays, dark matter, the Sunyaev-Zel dovich effect, the galaxy distribution in the universe, and the Lyman alpha forest. The group organized and hosted a number of conferences and workshop over the years covered by the grant. Among them were:

A preliminary theoretical line-blanketed model solar photosphere

NASA Technical Reports Server (NTRS)

Kurucz, R. L.

1974-01-01

In the theoretical approach to model-atmosphere construction, all opacities are computed theoretically and the temperature-pressure structure is determined by conservation of energy. Until recently, this has not been a very useful method for later type stars, because the line opacity was both poorly known and difficult to calculate. However, methods have now been developed that are capable of representing the line opacity well enough for construction of realistic models. A preliminary theoretical solar model is presented that produces closer agreement with observation than has been heretofore possible. The qualitative advantages and shortcomings of this model are discussued and projected improvements are outlined.

Accreting Binary Populations in the Earlier Universe

NASA Technical Reports Server (NTRS)

Hornschemeier, Ann

2010-01-01

It is now understood that X-ray binaries dominate the hard X-ray emission from normal star-forming galaxies. Thanks to the deepest (2-4 Ms) Chandra surveys, such galaxies are now being studied in X-rays out to z approximates 4. Interesting X-ray stacking results (based on 30+ galaxies per redshift bin) suggest that the mean rest-frame 2-10 keV luminosity from z=3-4 Lyman break galaxies (LBGs), is comparable to the most powerful starburst galaxies in the local Universe. This result possibly indicates a similar production mechanism for accreting binaries over large cosmological timescales. To understand and constrain better the production of X-ray binaries in high-redshift LBGs, we have utilized XMM-Newton observations of a small sample of z approximates 0.1 GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs); local analogs to high-redshift LBGs. Our observations enable us to study the X-ray emission from LBG-like galaxies on an individual basis, thus allowing us to constrain object-to-object variances in this population. We supplement these results with X-ray stacking constraints using the new 3.2 Ms Chandra Deep Field-South (completed spring 2010) and LBG candidates selected from HST, Swift UVOT, and ground-based data. These measurements provide new X-ray constraints that sample well the entire z=0-4 baseline

Experimental and theoretical investigation of relative optical band gaps in graphene generations

NASA Astrophysics Data System (ADS)

Bhatnagar, Deepika; Singh, Sukhbir; Yadav, Sriniwas; Kumar, Ashok; Kaur, Inderpreet

2017-01-01

Size and chemical functionalization dependant optical band gaps in graphene family nanomaterials were investigated by experimental and theoretical study using Tauc plot and density functional theory (DFT). We have synthesized graphene oxide through a modified Hummer’s method using graphene nanoplatelets and sequentially graphene quantum dots through hydrothermal reduction. The experimental results indicate that the optical band gap in graphene generations was altered by reducing the size of graphene sheets and attachment of chemical functionalities like epoxy, hydroxyl and carboxyl groups plays a crucial role in varying optical band gaps. It is further confirmed by DFT calculations that the π orbitals were more dominatingly participating in transitions shown by projected density of states and the molecular energy spectrum represented the effect of attached functional groups along with discreteness in energy levels. Theoretical results were found to be in good agreement with experimental results. All of the above different variants of graphene can be used in native or modified form for sensor design and optoelectronic applications.

A theoretical perspective on road safety communication campaigns.

PubMed

Elvik, Rune

2016-12-01

This paper proposes a theoretical perspective on road safety communication campaigns, which may help in identifying the conditions under which such campaigns can be effective. The paper proposes that, from a theoretical point of view, it is reasonable to assume that road user behaviour is, by and large, subjectively rational. This means that road users are assumed to behave the way they think is best. If this assumption is accepted, the best theoretical prediction is that road safety campaigns consisting of persuasive messages only will have no effect on road user behaviour and accordingly no effect on accidents. This theoretical prediction is not supported by meta-analyses of studies that have evaluated the effects of road safety communication campaigns. These analyses conclude that, on the average, such campaigns are associated with an accident reduction. The paper discusses whether this finding can be explained theoretically. The discussion relies on the distinction made by many modern theorists between bounded and perfect rationality. Road user behaviour is characterised by bounded rationality. Hence, if road users can gain insight into the bounds of their rationality, so that they see advantages to themselves of changing behaviour, they are likely to do so. It is, however, largely unknown whether such a mechanism explains why some road safety communication campaigns have been found to be more effective than others. Copyright © 2015 Elsevier Ltd. All rights reserved.

An empirical investigation of theoretical loss and gambling intensity.

PubMed

Auer, Michael; Griffiths, Mark D

2014-12-01

Many recent studies of internet gambling-particularly those that have analysed behavioural tracking data-have used variables such 'bet size' and 'number of games played' as proxy measures for 'gambling intensity'. In this paper it is argued that the most stable and reliable measure for 'gambling intensity' is the 'theoretical loss' (a product of total bet size and house advantage). In the long run, the theoretical loss corresponds with the Gross Gaming Revenue generated by commercial gaming operators. For shorter periods of time, theoretical loss is the most stable measure of gambling intensity as it is not distorted by gamblers' occasional wins. Even for single bets, the theoretical loss reflects the amount a player is willing to risk. Using behavioural tracking data of 100,000 players who played online casino, lottery and/or poker games, this paper also demonstrates that bet size does not equate to or explain theoretical loss as it does not take into account the house advantage. This lack of accuracy is shown to be even more pronounced for gamblers who play a variety of games.

High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: Part 1, data analysis and results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erskine, David J.; Edelstein, Jerry; Wishnow, Edward H.

High-resolution broadband spectroscopy at near-infrared wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar. Observations of stars were performed with the “TEDI” interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec near-infrared echelle spectrograph. These are the first multidelay EDI demonstrations on starlight, as earlier measurements used a single delay or laboratory sources. We demonstrate very high (10×) resolution boost, from original 2700 to 27,000 with current set of delays (up to 3 cm), well beyond the classical limits enforced bymore » the slit width and detector pixel Nyquist limit. Significantly, the EDI used with multiple delays rather than a single delay as used previously yields an order of magnitude or more improvement in the stability against native spectrograph point spread function (PSF) drifts along the dispersion direction. We observe a dramatic (20×) reduction in sensitivity to PSF shift using our standard processing. A recently realized method of further reducing the PSF shift sensitivity to zero is described theoretically and demonstrated in a simple simulation which produces a 350× times reduction. We demonstrate superb rejection of fixed pattern noise due to bad detector pixels—EDI only responds to changes in pixel intensity synchronous to applied dithering. This part 1 describes data analysis, results, and instrument noise. Lastly, a section on theoretical photon limited sensitivity is in a companion paper, part 2.« less

High-resolution broadband spectroscopy using externally dispersed interferometry at the Hale telescope: Part 1, data analysis and results

DOE PAGES

Erskine, David J.; Edelstein, Jerry; Wishnow, Edward H.; ...

2016-05-27

High-resolution broadband spectroscopy at near-infrared wavelengths (950 to 2450 nm) has been performed using externally dispersed interferometry (EDI) at the Hale telescope at Mt. Palomar. Observations of stars were performed with the “TEDI” interferometer mounted within the central hole of the 200-in. primary mirror in series with the comounted TripleSpec near-infrared echelle spectrograph. These are the first multidelay EDI demonstrations on starlight, as earlier measurements used a single delay or laboratory sources. We demonstrate very high (10×) resolution boost, from original 2700 to 27,000 with current set of delays (up to 3 cm), well beyond the classical limits enforced bymore » the slit width and detector pixel Nyquist limit. Significantly, the EDI used with multiple delays rather than a single delay as used previously yields an order of magnitude or more improvement in the stability against native spectrograph point spread function (PSF) drifts along the dispersion direction. We observe a dramatic (20×) reduction in sensitivity to PSF shift using our standard processing. A recently realized method of further reducing the PSF shift sensitivity to zero is described theoretically and demonstrated in a simple simulation which produces a 350× times reduction. We demonstrate superb rejection of fixed pattern noise due to bad detector pixels—EDI only responds to changes in pixel intensity synchronous to applied dithering. This part 1 describes data analysis, results, and instrument noise. Lastly, a section on theoretical photon limited sensitivity is in a companion paper, part 2.« less

Experimental and theoretical studies of near-ground acoustic radiation propagation in the atmosphere

NASA Astrophysics Data System (ADS)

Belov, Vladimir V.; Burkatovskaya, Yuliya B.; Krasnenko, Nikolai P.; Rakov, Aleksandr S.; Rakov, Denis S.; Shamanaeva, Liudmila G.

2017-11-01

Results of experimental and theoretical studies of the process of near-ground propagation of monochromatic acoustic radiation on atmospheric paths from a source to a receiver taking into account the contribution of multiple scattering on fluctuations of atmospheric temperature and wind velocity, refraction of sound on the wind velocity and temperature gradients, and its reflection by the underlying surface for different models of the atmosphere depending the sound frequency, coefficient of reflection from the underlying surface, propagation distance, and source and receiver altitudes are presented. Calculations were performed by the Monte Carlo method using the local estimation algorithm by the computer program developed by the authors. Results of experimental investigations under controllable conditions are compared with theoretical estimates and results of analytical calculations for the Delany-Bazley impedance model. Satisfactory agreement of the data obtained confirms the correctness of the suggested computer program.

Health Disparities in Mid-to-Late Life: The Role of Earlier Life Family and Neighborhood Socioeconomic Conditions

PubMed Central

Johnson, Rucker C.; Schoeni, Robert F.; Rogowski, Jeannette A.

2012-01-01

The relationship between neighborhoods of residence in young adulthood and health in mid to late life in the United States are examined using the 1968-2005 waves of the Panel Study of Income Dynamics (PSID). The sample consists of persons who were aged 20-30 in 1968 and are followed for a period of 38 years (N=2,730). Four-level hierarchical random effects models of self-assessed general health status as a function of individual, family, and neighborhood factors are estimated. Using the original sampling design of the PSID, we analyze adult health trajectories of married couples and neighbors followed from young adulthood through elderly ages to assess the magnitudes of the possible causal effects of family and neighborhood characteristics in young adulthood on health in mid to late life. Estimates suggest disparities in neighborhood conditions in young adulthood account for one-quarter of the variation in mid-to-late-life health. Living in poor neighborhoods during young adulthood is strongly associated with negative health outcomes in later life. This result is robust even in the presence of a reasonably large amount of potential unobservable individual and family factors that may significantly affect both neighborhood of residence and subsequent health status. Racial differences in health status in mid to late life are also associated with family and neighborhood socioeconomic conditions earlier in life. Three quarters of the black-white gap in health status at ages over 55 can be accounted for by differences in childhood socioeconomic status and neighborhood and family factors in young adulthood. PMID:22212443

Technology as a Bypass for a Lack of Theoretical Knowledge

ERIC Educational Resources Information Center

Picard, Thierry Dana

2004-01-01

In a previous paper, we showed the importance of using low-level commands of a CAS in order to enhance the students' conceptual insight into mathematics. In this paper, we wish to emphasise a different use of a CAS, which makes possible the exploration of new topics, when the necessary theoretical results have still not been acquired, and avoids…

The pressure distribution for biharmonic transmitting array: theoretical study

NASA Astrophysics Data System (ADS)

Baranowska, A.

2005-03-01

The aim of the paper is theoretical analysis of the finite amplitude waves interaction problem for the biharmonic transmitting array. We assume that the array consists of 16 circular pistons of the same dimensions that regrouped in two sections. Two different arrangements of radiating elements were considered. In this situation the radiating surface is non-continuous without axial symmetry. The mathematical model was built on the basis of the Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation. To solve the problem the finite-difference method was applied. On-axis pressure amplitude for different frequency waves as a function of distance from the source, transverse pressure distribution of these waves at fixed distances from the source and pressure amplitude distribution for them at fixed planes were examined. Especially changes of normalized pressure amplitude for difference frequency were studied. The paper presents mathematical model and some results of theoretical investigations obtained for different values of source parameters.

Theoretical modeling of critical temperature increase in metamaterial superconductors

NASA Astrophysics Data System (ADS)

Smolyaninov, Igor; Smolyaninova, Vera

Recent experiments have demonstrated that the metamaterial approach is capable of drastic increase of the critical temperature Tc of epsilon near zero (ENZ) metamaterial superconductors. For example, tripling of the critical temperature has been observed in Al-Al2O3 ENZ core-shell metamaterials. Here, we perform theoretical modelling of Tc increase in metamaterial superconductors based on the Maxwell-Garnett approximation of their dielectric response function. Good agreement is demonstrated between theoretical modelling and experimental results in both aluminum and tin-based metamaterials. Taking advantage of the demonstrated success of this model, the critical temperature of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is evaluated. The MgB2-based metamaterial superconductors are projected to reach the liquid nitrogen temperature range. In the case of an H2S-based metamaterial Tc appears to reach 250 K. This work was supported in part by NSF Grant DMR-1104676 and the School of Emerging Technologies at Towson University.

Role of information theoretic uncertainty relations in quantum theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jizba, Petr, E-mail: p.jizba@fjfi.cvut.cz; ITP, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin; Dunningham, Jacob A., E-mail: J.Dunningham@sussex.ac.uk

2015-04-15

Uncertainty relations based on information theory for both discrete and continuous distribution functions are briefly reviewed. We extend these results to account for (differential) Rényi entropy and its related entropy power. This allows us to find a new class of information-theoretic uncertainty relations (ITURs). The potency of such uncertainty relations in quantum mechanics is illustrated with a simple two-energy-level model where they outperform both the usual Robertson–Schrödinger uncertainty relation and Shannon entropy based uncertainty relation. In the continuous case the ensuing entropy power uncertainty relations are discussed in the context of heavy tailed wave functions and Schrödinger cat states. Again,more » improvement over both the Robertson–Schrödinger uncertainty principle and Shannon ITUR is demonstrated in these cases. Further salient issues such as the proof of a generalized entropy power inequality and a geometric picture of information-theoretic uncertainty relations are also discussed.« less

Theoretical prediction and impact of fundamental electric dipole moments

DOE PAGES

Ellis, Sebastian A. R.; Kane, Gordon L.

2016-01-13

The predicted Standard Model (SM) electric dipole moments (EDMs) of electrons and quarks are tiny, providing an important window to observe new physics. Theories beyond the SM typically allow relatively large EDMs. The EDMs depend on the relative phases of terms in the effective Lagrangian of the extended theory, which are generally unknown. Underlying theories, such as string/M-theories compactified to four dimensions, could predict the phases and thus EDMs in the resulting supersymmetric (SUSY) theory. Earlier one of us, with collaborators, made such a prediction and found, unexpectedly, that the phases were predicted to be zero at tree level inmore » the theory at the unification or string scale ~O(10 16 GeV). Electroweak (EW) scale EDMs still arise via running from the high scale, and depend only on the SM Yukawa couplings that also give the CKM phase. Here we extend the earlier work by studying the dependence of the low scale EDMs on the constrained but not fully known fundamental Yukawa couplings. The dominant contribution is from two loop diagrams and is not sensitive to the choice of Yukawa texture. The electron EDM should not be found to be larger than about 5 × 10 –30e cm, and the neutron EDM should not be larger than about 5 × 10 –29e cm. These values are quite a bit smaller than the reported predictions from Split SUSY and typical effective theories, but much larger than the Standard Model prediction. Also, since models with random phases typically give much larger EDMs, it is a significant testable prediction of compactified M-theory that the EDMs should not be above these upper limits. The actual EDMs can be below the limits, so once they are measured they could provide new insight into the fundamental Yukawa couplings of leptons and quarks. As a result, we comment also on the role of strong CP violation. EDMs probe fundamental physics near the Planck scale.« less

Theoretical prediction and impact of fundamental electric dipole moments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, Sebastian A. R.; Kane, Gordon L.

The predicted Standard Model (SM) electric dipole moments (EDMs) of electrons and quarks are tiny, providing an important window to observe new physics. Theories beyond the SM typically allow relatively large EDMs. The EDMs depend on the relative phases of terms in the effective Lagrangian of the extended theory, which are generally unknown. Underlying theories, such as string/M-theories compactified to four dimensions, could predict the phases and thus EDMs in the resulting supersymmetric (SUSY) theory. Earlier one of us, with collaborators, made such a prediction and found, unexpectedly, that the phases were predicted to be zero at tree level inmore » the theory at the unification or string scale ~O(10 16 GeV). Electroweak (EW) scale EDMs still arise via running from the high scale, and depend only on the SM Yukawa couplings that also give the CKM phase. Here we extend the earlier work by studying the dependence of the low scale EDMs on the constrained but not fully known fundamental Yukawa couplings. The dominant contribution is from two loop diagrams and is not sensitive to the choice of Yukawa texture. The electron EDM should not be found to be larger than about 5 × 10 –30e cm, and the neutron EDM should not be larger than about 5 × 10 –29e cm. These values are quite a bit smaller than the reported predictions from Split SUSY and typical effective theories, but much larger than the Standard Model prediction. Also, since models with random phases typically give much larger EDMs, it is a significant testable prediction of compactified M-theory that the EDMs should not be above these upper limits. The actual EDMs can be below the limits, so once they are measured they could provide new insight into the fundamental Yukawa couplings of leptons and quarks. As a result, we comment also on the role of strong CP violation. EDMs probe fundamental physics near the Planck scale.« less

Comments on theoretical foundation of "EM Drive"

NASA Astrophysics Data System (ADS)

Wu, C.-W.

2018-03-01

The concept of EM Drive has attracted much attention and groups of work have been conducted to prove or verify it, of which the published experimental outcome is criticized in great details while the theoretical foundation has not been discussed. The present essay investigates on the theoretical derivations of the net thrust in the "EM drive" and reveals the self-contradiction arising at the very start, when the law of conservation of momentum was utilized and opposed simultaneously.

The Future of Theoretical Physics and Cosmology

NASA Astrophysics Data System (ADS)

Gibbons, G. W.; Shellard, E. P. S.; Rankin, S. J.

2003-11-01

Based on lectures given in honor of Stephen Hawking's 60th birthday, this book comprises contributions from the world's leading theoretical physicists. Popular lectures progress to a critical evaluation of more advanced subjects in modern cosmology and theoretical physics. Topics covered include the origin of the universe, warped spacetime, cosmological singularities, quantum gravity, black holes, string theory, quantum cosmology and inflation. The volume provides a fascinating overview of the variety of subjects to which Stephen Hawking has contributed.

Theoretical analysis of intracortical microelectrode recordings

NASA Astrophysics Data System (ADS)

Lempka, Scott F.; Johnson, Matthew D.; Moffitt, Michael A.; Otto, Kevin J.; Kipke, Daryl R.; McIntyre, Cameron C.

2011-08-01

Advanced fabrication techniques have now made it possible to produce microelectrode arrays for recording the electrical activity of a large number of neurons in the intact brain for both clinical and basic science applications. However, the long-term recording performance desired for these applications is hindered by a number of factors that lead to device failure or a poor signal-to-noise ratio (SNR). The goal of this study was to identify factors that can affect recording quality using theoretical analysis of intracortical microelectrode recordings of single-unit activity. Extracellular microelectrode recordings were simulated with a detailed multi-compartment cable model of a pyramidal neuron coupled to a finite-element volume conductor head model containing an implanted recording microelectrode. Recording noise sources were also incorporated into the overall modeling infrastructure. The analyses of this study would be very difficult to perform experimentally; however, our model-based approach enabled a systematic investigation of the effects of a large number of variables on recording quality. Our results demonstrate that recording amplitude and noise are relatively independent of microelectrode size, but instead are primarily affected by the selected recording bandwidth, impedance of the electrode-tissue interface and the density and firing rates of neurons surrounding the recording electrode. This study provides the theoretical groundwork that allows for the design of the microelectrode and recording electronics such that the SNR is maximized. Such advances could help enable the long-term functionality required for chronic neural recording applications.

Theoretical analysis of intracortical microelectrode recordings

PubMed Central

Lempka, Scott F; Johnson, Matthew D; Moffitt, Michael A; Otto, Kevin J; Kipke, Daryl R; McIntyre, Cameron C

2011-01-01

Advanced fabrication techniques have now made it possible to produce microelectrode arrays for recording the electrical activity of a large number of neurons in the intact brain for both clinical and basic science applications. However, the long-term recording performance desired for these applications is hindered by a number of factors that lead to device failure or a poor signal-to-noise ratio (SNR). The goal of this study was to identify factors that can affect recording quality using theoretical analysis of intracortical microelectrode recordings of single-unit activity. Extracellular microelectrode recordings were simulated with a detailed multi-compartment cable model of a pyramidal neuron coupled to a finite element volume conductor head model containing an implanted recording microelectrode. Recording noise sources were also incorporated into the overall modeling infrastructure. The analyses of this study would be very difficult to perform experimentally; however, our model-based approach enabled a systematic investigation of the effects of a large number of variables on recording quality. Our results demonstrate that recording amplitude and noise are relatively independent of microelectrode size, but instead are primarily affected by the selected recording bandwidth, impedance of the electrode-tissue interface, and the density and firing rates of neurons surrounding the recording electrode. This study provides the theoretical groundwork that allows for the design of the microelectrode and recording electronics such that the SNR is maximized. Such advances could help enable the long-term functionality required for chronic neural recording applications. PMID:21775783

Theoretical and observational constraints on Tachyon Inflation

NASA Astrophysics Data System (ADS)

Barbosa-Cendejas, Nandinii; De-Santiago, Josue; German, Gabriel; Hidalgo, Juan Carlos; Rigel Mora-Luna, Refugio

2018-03-01

We constrain several models in Tachyonic Inflation derived from the large-N formalism by considering theoretical aspects as well as the latest observational data. On the theoretical side, we assess the field range of our models by means of the excursion of the equivalent canonical field. On the observational side, we employ BK14+PLANCK+BAO data to perform a parameter estimation analysis as well as a Bayesian model selection to distinguish the most favoured models among all four classes here presented. We observe that the original potential V propto sech(T) is strongly disfavoured by observations with respect to a reference model with flat priors on inflationary observables. This realisation of Tachyon inflation also presents a large field range which may demand further quantum corrections. We also provide examples of potentials derived from the polynomial and the perturbative classes which are both statistically favoured and theoretically acceptable.

Theoretical Principles of Distance Education.

ERIC Educational Resources Information Center

Keegan, Desmond, Ed.

This book contains the following papers examining the didactic, academic, analytic, philosophical, and technological underpinnings of distance education: "Introduction"; "Quality and Access in Distance Education: Theoretical Considerations" (D. Randy Garrison); "Theory of Transactional Distance" (Michael G. Moore);…

Theoretical kinetics study of the F((2)P) + NH3 hydrogen abstraction reaction.

PubMed

Espinosa-Garcia, J; Fernandez-Ramos, A; Suleimanov, Y V; Corchado, J C

2014-01-23

The hydrogen abstraction reaction of fluorine with ammonia represents a true chemical challenge because it is very fast, is followed by secondary abstraction reactions, which are also extremely fast, and presents an experimental/theoretical controversy about rate coefficients. Using a previously developed full-dimensional analytical potential energy surface, we found that the F + NH3 → HF + NH2 system is a barrierless reaction with intermediate complexes in the entry and exit channels. In order to understand the reactivity of the title reaction, thermal rate coefficidents were calculated using two approaches: ring polymer molecular dynamics and quasi-classical trajectory calculations, and these were compared with available experimental data for the common temperature range 276-327 K. The theoretical results obtained show behavior practically independent of temperature, reproducing Walther-Wagner's experiment, but in contrast with Persky's more recent experiment. However, quantitatively, our results are 1 order of magnitude larger than those of Walther-Wagner and reasonably agree with the Persky at the lowest temperature, questioning so Walther-Wagner's older data. At present, the reason for this discrepancy is not clear, although we point out some possible reasons in the light of current theoretical calculations.

Biology is more theoretical than physics.

PubMed

Gunawardena, Jeremy

2013-06-01

The word "theory" is used in at least two senses--to denote a body of widely accepted laws or principles, as in "Darwinian theory" or "quantum theory," and to suggest a speculative hypothesis, often relying on mathematical analysis, that has not been experimentally confirmed. It is often said that there is no place for the second kind of theory in biology and that biology is not theoretical but based on interpretation of data. Here, ideas from a previous essay are expanded upon to suggest, to the contrary, that the second kind of theory has always played a critical role and that biology, therefore, is a good deal more theoretical than physics.

Theoretical foundations of learning through simulation.

PubMed

Zigmont, Jason J; Kappus, Liana J; Sudikoff, Stephanie N

2011-04-01

Health care simulation is a powerful educational tool to help facilitate learning for clinicians and change their practice to improve patient outcomes and safety. To promote effective life-long learning through simulation, the educator needs to consider individuals, their experiences, and their environments. Effective education of adults through simulation requires a sound understanding of both adult learning theory and experiential learning. This review article provides a framework for developing and facilitating simulation courses, founded upon empiric and theoretic research in adult and experiential learning. Specifically, this article provides a theoretic foundation for using simulation to change practice to improve patient outcomes and safety. Copyright © 2011 Elsevier Inc. All rights reserved.

Research in Theoretical Particle Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ralston, John P.

This document is the final report on activity of the University of Kansas theory group supported under DOE Grant Number DE-FG02-04ER14308, ending April 30, 3013. The report covers the most recent three year period period May 1, 2010-April 30, 2013. Faculty supported by the grant during the period were Danny Marfatia (co-I), Douglas McKay (emeritus) and John Ralston (PI). The group's research topics and accomplishments covered numerous different topics subsumed under the {\\it the Energy Frontier, the Intensity Frontier}, and {\\it the Cosmic Frontier}. Many theoretical and experimental results related to the Standard Model and models of new physics weremore » published during the reporting period. The group's research emphasis has been on challenging and confronting {\\it Anything that is Observable} about the physical Universe.« less

Long-term application of computer-based pleoptics in home therapy: selected results of a prospective multicenter study.

PubMed

Kämpf, Uwe; Shamshinova, Angelika; Kaschtschenko, Tamara; Mascolus, Wilfried; Pillunat, Lutz; Haase, Wolfgang

2008-01-01

The paper presents selected results of a prospective multicenter study. The reported study was aimed at the evaluation of a software-based stimulation method of computer training applied in addition to occlusion as a complementary treatment for therapy-resistant cases of amblyopia. The stimulus was a drifting sinusoidal grating of a spatial frequency of 0.3 cyc/deg and a temporal frequency of 1 cyc/sec, reciprocally coordinated with each other to a drift of 0.33 deg/sec. This pattern was implemented as a background stimulus into simple computer games to bind attention by sensory-motor coordination tasks. According to an earlier proposed hypothesis, the stimulation aims at the provocation of stimulus-induced phase-coupling in order to contribute to the refreshment of synchronization and coordination processes in the visual transmission channels. To assess the outcome of the therapy, we studied the development of the visual acuity during a period of 6 months. Our cooperating partners of this prospective multicenter study were strabologic departments in ophthalmic clinics and private practices as well. For the issue of therapy control, a partial sample of 55 patients from an overall sample of 198 patients was selected, according to the criterion of strong therapy resistance. The visual acuity was increased about two logarithmic steps by an occlusion combined with computer training in addition to the earlier obtained gain of the same amount by occlusion alone. Recalculated relatively to the duration of the therapy periods, the computer training combined with occlusion was found to be about twice as effective as the preceding occlusion alone. The results of combined computer training and occlusion show an additional increase of the same amount as the preceding occlusion alone, which yielded at its end no further advantage to the development of visual acuity in the selected sample of our 55 therapy-resistant patients. In a concluding theoretical note, a preliminary

The first dozen years of the history of ITEP Theoretical Physics Laboratory

NASA Astrophysics Data System (ADS)

Ioffe, B. L.

2013-01-01

The theoretical investigations at ITEP in the years 1945 - 1958 are reviewed. There are exposed the most important theoretical results, obtained in the following branches of physics: (1) the theory of nuclear reactors on thermal neutrons; (2) the hydrogen bomb project ("Tube" in USSR and "Classical Super" in USA); (3) radiation theory; (4) low temperature physics; (5) quantum electrodynamics and quantum field theories; (6) parity violation in weak interactions, the theory of β-decay and other weak processes; (7) strong interaction and nuclear physics. To the review are added the English translations of a few papers, originally published in Russian, but unknown (or almost unknown) to Western readers.

Theoretical tuning of the firefly bioluminescence spectra by the modification of oxyluciferin

NASA Astrophysics Data System (ADS)

Cheng, Yuan-Yuan; Zhu, Jia; Liu, Ya-Jun

2014-01-01

Extending the firefly bioluminescence is of practical significance for the improved visualization of living cells and the development of a multicolor reporter. Tuning the color of bioluminescence in fireflies mainly involves the modification of luciferase and luciferin. In this Letter, we theoretically studied the emission spectra of 9 firefly oxyluciferin analogs in the gas phase and in solutions. Three density functionals, including B3LYP, CAM-B3LYP and M06-2X, were employed to theoretically predict the efficiently luminescent analogs. The reliable functionals for calculating the targeted systems were suggested. The luminescence efficiency, solvent effects, and substituent effects are discussed based on the calculated results.

Synthesis of 2-(bis(cyanomethyl)amino)-2-oxoethyl methacrylate monomer molecule and its characterization by experimental and theoretical methods

NASA Astrophysics Data System (ADS)

Sas, E. B.; Cankaya, N.; Kurt, M.

2018-06-01

In this work 2-(bis(cyanomethyl)amino)-2-oxoethyl methacrylate monomer has been synthesized as newly, characterized both experimentally and theoretically. Experimentally, it has been characterized by FT-IR, FT-Raman, 1H and 13C NMR spectroscopy techniques. The theoretical calculations have been performed with Density Functional Theory (DFT) including B3LYP method. The scaled theoretical wavenumbers have been assigned based on total energy distribution (TED). Electronic properties of monomer have been performed using time-dependent TD-DFT/B3LYP/B3LYP/6-311G++(d,p) method. The results of experimental have been compared with theoretical values. Both experimental and theoretical methods have shown that the monomer was suitable for the literature.

TEST OF A THEORETICAL COMMUTER EXPOSURE MODEL TO VEHICLE EXHAUST IN TRAFFIC

EPA Science Inventory

A theoretical model of commuter exposure is presented as a box or cell model with the automobile passenger compartment representing the microenvironment exposed to CO concentrations resulting from vehicle exhaust leaks and emissions from traffic. Equations which describe this sit...

Theoretical considerations for mapping activation in human cardiac fibrillation

NASA Astrophysics Data System (ADS)

Rappel, Wouter-Jan; Narayan, Sanjiv M.

2013-06-01

Defining mechanisms for cardiac fibrillation is challenging because, in contrast to other arrhythmias, fibrillation exhibits complex non-repeatability in spatiotemporal activation but paradoxically exhibits conserved spatial gradients in rate, dominant frequency, and electrical propagation. Unlike animal models, in which fibrillation can be mapped at high spatial and temporal resolution using optical dyes or arrays of contact electrodes, mapping of cardiac fibrillation in patients is constrained practically to lower resolutions or smaller fields-of-view. In many animal models, atrial fibrillation is maintained by localized electrical rotors and focal sources. However, until recently, few studies had revealed localized sources in human fibrillation, so that the impact of mapping constraints on the ability to identify rotors or focal sources in humans was not described. Here, we determine the minimum spatial and temporal resolutions theoretically required to detect rigidly rotating spiral waves and focal sources, then extend these requirements for spiral waves in computer simulations. Finally, we apply our results to clinical data acquired during human atrial fibrillation using a novel technique termed focal impulse and rotor mapping (FIRM). Our results provide theoretical justification and clinical demonstration that FIRM meets the spatio-temporal resolution requirements to reliably identify rotors and focal sources for human atrial fibrillation.

Theoretical study of heat transfer with moving phase-change interface in thawing of frozen food

NASA Astrophysics Data System (ADS)

Leung, M.; Ching, W. H.; Leung, D. Y. C.; Lam, G. C. K.

2005-02-01

A theoretical solution was obtained for a transient phase-change heat transfer problem in thawing of frozen food. In the physical model, a sphere originally at a uniform temperature below the phase-change temperature is suddenly immersed in a fluid at a temperature above the phase-change temperature. As the body temperature increases, the phase-change interface will be first formed on the surface. Subsequently, the interface will absorb the latent heat and move towards the centre until the whole body undergoes complete phase change. In the mathematical formulation, the nonhomogeneous problem arises from the moving phase-change interface. The solution in terms of the time-dependent temperature field was obtained by use of Green's function. A one-step Newton-Raphson method was specially designed to solve for the position of the moving interface to satisfy the interface condition. The theoretical results were compared with numerical results generated by a finite difference model and experimental measurements collected from a cold water thawing process. As a good agreement was found, the theoretical solution developed in this study was verified numerically and experimentally. Besides thawing of frozen food, there are many other practical applications of the theoretical solution, such as food freezing, soil freezing/thawing, metal casting and bath quenching heat treatment, among others.

Viewpoints on the 2017 American Conference on Theoretical Chemistry

DOE PAGES

Goldsmith, Zachary K.; Provazza, Justin; Seritan, Stefan

2017-10-19

From July 17th to 21st, theoretical chemists from the United States and abroad gathered at Boston University to take part in the 2017 American Conference on Theoretical Chemistry (ACTC, http://meetatbu.com/actc). The ACTC grew out of a Gordon Research Conference held biennially from 1962 to 1970. The conference in its current form has been held every three years since 1972. The 2017 conference was chaired by Sharon Hammes-Schiffer (Univ. of Illinois at Urbana-Champaign) and vice-chaired by Todd J. Martiń ez (Stanford Univ). David F. Coker of Boston University served as the Deputy Chair and Local Organizer. More than 30 professors atmore » the forefronts of their respective fields gave talks describing recent research developments. Additionally, over 170 students and postdocs contributed posters detailing their research efforts in theoretical chemistry and its numerous intersecting disciplines. This Viewpoint contains accounts of many of the talks given at the ACTC, delineated by the following concentrations: energy and electron transfer, materials and interfaces, quantum dynamics and spectroscopy, electronic structure, machine learning, and modeling in solution and biological environments. However, most talks could have easily been categorized under two or more of the concentrations listed, emblematic of the large and growing interdisciplinarity in the theoretical chemistry community. The 2017 ACTC was a demonstration of both the depth at which theoretical chemists are understanding fundamental phenomena and the large breadth of topics to which a theoretical chemistry perspective is being applied.« less

Viewpoints on the 2017 American Conference on Theoretical Chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldsmith, Zachary K.; Provazza, Justin; Seritan, Stefan

From July 17th to 21st, theoretical chemists from the United States and abroad gathered at Boston University to take part in the 2017 American Conference on Theoretical Chemistry (ACTC, http://meetatbu.com/actc). The ACTC grew out of a Gordon Research Conference held biennially from 1962 to 1970. The conference in its current form has been held every three years since 1972. The 2017 conference was chaired by Sharon Hammes-Schiffer (Univ. of Illinois at Urbana-Champaign) and vice-chaired by Todd J. Martiń ez (Stanford Univ). David F. Coker of Boston University served as the Deputy Chair and Local Organizer. More than 30 professors atmore » the forefronts of their respective fields gave talks describing recent research developments. Additionally, over 170 students and postdocs contributed posters detailing their research efforts in theoretical chemistry and its numerous intersecting disciplines. This Viewpoint contains accounts of many of the talks given at the ACTC, delineated by the following concentrations: energy and electron transfer, materials and interfaces, quantum dynamics and spectroscopy, electronic structure, machine learning, and modeling in solution and biological environments. However, most talks could have easily been categorized under two or more of the concentrations listed, emblematic of the large and growing interdisciplinarity in the theoretical chemistry community. The 2017 ACTC was a demonstration of both the depth at which theoretical chemists are understanding fundamental phenomena and the large breadth of topics to which a theoretical chemistry perspective is being applied.« less

Stellar granulation as seen in disk-integrated intensity. II. Theoretical scaling relations compared with observations

NASA Astrophysics Data System (ADS)

Samadi, R.; Belkacem, K.; Ludwig, H.-G.; Caffau, E.; Campante, T. L.; Davies, G. R.; Kallinger, T.; Lund, M. N.; Mosser, B.; Baglin, A.; Mathur, S.; Garcia, R. A.

2013-11-01

Context. A large set of stars observed by CoRoT and Kepler shows clear evidence for the presence of a stellar background, which is interpreted to arise from surface convection, i.e., granulation. These observations show that the characteristic time-scale (τeff) and the root-mean-square (rms) brightness fluctuations (σ) associated with the granulation scale as a function of the peak frequency (νmax) of the solar-like oscillations. Aims: We aim at providing a theoretical background to the observed scaling relations based on a model developed in Paper I. Methods: We computed for each 3D model the theoretical power density spectrum (PDS) associated with the granulation as seen in disk-integrated intensity on the basis of the theoretical model published in Paper I. For each PDS we derived the associated characteristic time (τeff) and the rms brightness fluctuations (σ) and compared these theoretical values with the theoretical scaling relations derived from the theoretical model and the measurements made on a large set of Kepler targets. Results: We derive theoretical scaling relations for τeff and σ, which show the same dependence on νmax as the observed scaling relations. In addition, we show that these quantities also scale as a function of the turbulent Mach number (ℳa) estimated at the photosphere. The theoretical scaling relations for τeff and σ match the observations well on a global scale. Quantitatively, the remaining discrepancies with the observations are found to be much smaller than previous theoretical calculations made for red giants. Conclusions: Our modelling provides additional theoretical support for the observed variations of σ and τeff with νmax. It also highlights the important role of ℳa in controlling the properties of the stellar granulation. However, the observations made with Kepler on a wide variety of stars cannot confirm the dependence of our scaling relations on ℳa. Measurements of the granulation background and

Theoretical studies of spectroscopic problems of importance for atmospheric radiation measurements

NASA Technical Reports Server (NTRS)

Tipping, Richard H.

1994-01-01

Many of the instruments used to deduce the physical parameters of the Earth's atmosphere necessary for climate studies or for pollution monitoring (for instance, temperature versus pressure or number densities of trace molecules) rely on the existence of accurate spectroscopic data and an understanding of the physical processes responsible for the absorption or emission of radiation. During the summer, research was either continued or begun on three distinct problems: (1) an improved theoretical framework for the calculation of the far-wing absorption of allowed spectral lines; (2) a refinement of the calculation of the collision-induced fundamental spectrum of N2; and (3) an investigation of possible line-mixing effects in the fundamental spectrum of CH4. Progress in these three areas is summarized below. During the past few years, we have developed a theoretical framework for the calculation of the absorption of radiation by the far wings of spectral lines. Such absorption due to water vapor plays a crucial role in the greenhouse effect as well as limiting the retrieval of temperature profiles from satellite data. Several improvements in the theory have been made and the results are being prepared for publication. Last year we published results for the theoretical calculation of the absorption of radiation due to the dipoles induced during binary collisions of N2 molecules using independently measured molecular parameters; the results were in reasonable agreement with experimental data. However, recent measurements have revealed new fine structure that has been attributed to line-mixing effects. We do not think that this is correct, rather that the structure results from short-range anisotropic dipoles. We are in the process of including this refinement in our theoretical calculation in order to compare with the new experimental data. Subtle changes in the spectra of CH4 measured by researchers at Langley have also been attributed to line-mixing effects. By

Nursing management of sensory overload in psychiatry – development of a theoretical framework model

PubMed

Scheydt, Stefan; Needham, Ian; Nielsen, Gunnar H; Behrens, Johann

2016-09-01

Background: The concept of “removal from stimuli” has already been examined by a Delphi-Study. However, some knowledge gaps remained open, which have now been further investigated. Aim: Examination of the concept “management of sensory overload in inpatient psychiatry” including its sub-concepts and specific measures. Method: Analysis of qualitative data about “removal from stimuli” by content analysis according to Mayring. Results: A theoretical description and definition of the concept could be achieved. In addition, sub-concepts (removal from stimuli, modulation of environmental factors, help somebody to help him-/herself) could be identified, theoretical defined and complemented by possible specific measures. Conclusions: The conceptual descriptions provide a further step to raise awareness of professionals in the subject area. Furthermore, we created a theoretical basis for further empirical studies.

Thought for application and application with thought: issues in theoretical thinking and practical wisdom.

PubMed

Jenkins, Sandra K; Thomas, Mary Beth

2005-01-01

Both theoretical thinking and practical wisdom are used by health professionals in their clinical practice. Lately, discussion has centered on the abstract phrase "theory-practice gap." The health profession is not the only discipline that seeks unity in theory and practice issues. Education is also building bridges in this arena. One reoccurring myth is the notion that theory and practice are separate; as a result, this gives a mistaken impression that theory serves no purpose in practice. Discussion of the issues in this paper includes definitions of theoretical thinking and practical wisdom, theoretical and practical knowledge development, and relevance to health professional's education, practice and science. These issues must be communicated to practitioners, educators and theorists. A collective definition to begin communication is proposed and suggestions are offered for addressing key issues.

Theorising Teaching and Learning: Pre-Service Teachers' Theoretical Awareness of Learning

ERIC Educational Resources Information Center

Brante, Göran; Holmqvist Olander, Mona; Holmquist, Per-Ola; Palla, Marta

2015-01-01

We examine pre-service teachers' theoretical learning during one five-week training module, and their educators' learning about better lecture design to foster student learning. The study is iterative: interventions (one per group) were implemented sequentially in student groups A-C, the results of the previous intervention serving as the baseline…

Lightning Talks 2015: Theoretical Division

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shlachter, Jack S.

2015-11-25

This document is a compilation of slides from a number of student presentations given to LANL Theoretical Division members. The subjects cover the range of activities of the Division, including plasma physics, environmental issues, materials research, bacterial resistance to antibiotics, and computational methods.

Topics in Theoretical Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, Andrew; Schmaltz, Martin; Katz, Emmanuel

This award supported a broadly based research effort in theoretical particle physics, including research aimed at uncovering the laws of nature at short (subatomic) and long (cosmological) distances. These theoretical developments apply to experiments in laboratories such as CERN, the facility that operates the Large Hadron Collider outside Geneva, as well as to cosmological investigations done using telescopes and satellites. The results reported here apply to physics beyond the so-called Standard Model of particle physics; physics of high energy collisions such as those observed at the Large Hadron Collider; theoretical and mathematical tools and frameworks for describing the laws ofmore » nature at short distances; cosmology and astrophysics; and analytic and computational methods to solve theories of short distance physics. Some specific research accomplishments include + Theories of the electroweak interactions, the forces that give rise to many forms of radioactive decay; + Physics of the recently discovered Higgs boson. + Models and phenomenology of dark matter, the mysterious component of the universe, that has so far been detected only by its gravitational effects. + High energy particles in astrophysics and cosmology. + Algorithmic research and Computational methods for physics of and beyond the Standard Model. + Theory and applications of relativity and its possible limitations. + Topological effects in field theory and cosmology. + Conformally invariant systems and AdS/CFT. This award also supported significant training of students and postdoctoral fellows to lead the research effort in particle theory for the coming decades. These students and fellows worked closely with other members of the group as well as theoretical and experimental colleagues throughout the physics community. Many of the research projects funded by this grant arose in response to recently obtained experimental results in the areas of particle physics and cosmology. We describe a

Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves

NASA Astrophysics Data System (ADS)

Chen, Hui; Cai, Li-Xun

2018-04-01

Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

The two faces of selective memory retrieval: Earlier decline of the beneficial than the detrimental effect with older age.

PubMed

Aslan, Alp; Schlichting, Andreas; John, Thomas; Bäuml, Karl-Heinz T

2015-12-01

Recent work with young adults has shown that, depending on study context access, selective memory retrieval can both impair and improve recall of other memories (Bäuml & Samenieh, 2010). Here, we investigated the 2 opposing effects of selective retrieval in older age. In Experiment 1, we examined 64 younger (20-35 years) and 64 older participants (above 60 years), and manipulated study context access using list-method directed forgetting. Whereas both age groups showed a detrimental effect of selective retrieval on to-be-remembered items, only younger but not older adults showed a beneficial effect on to-be-forgotten items. In Experiment 2, we examined 112 participants from a relatively wide age range (40-85 years), and manipulated study context access by varying the retention interval between study and test. Overall, a detrimental effect of selective retrieval arose when the retention interval was relatively short, but a beneficial effect when the retention interval was prolonged. Critically, the size of the beneficial but not the detrimental effect of retrieval decreased with age and this age-related decline was mediated by individuals' working memory capacity, as measured by the complex operation span task. Together, the results suggest an age-related dissociation in retrieval dynamics, indicating an earlier decline of the beneficial than the detrimental effect of selective retrieval with older age. (c) 2015 APA, all rights reserved).

Molecular dynamics study of the conformational properties of cyclohexadecane

NASA Astrophysics Data System (ADS)

Zhang, Renshi; Mattice, Wayne L.

1993-06-01

Molecular dynamics has been used for the first time for the study of the conformational properties of cyclohexadecane, c-C16H32. By analyzing a long molecular dynamics trajectory (14.5 ns) at 450 K, equilibrium statistics such as the relative populations of different isomeric conformers and the probability ratios, p(gt)/p(tt), p(gg)/p(tt), and p(gg)/p(gtg), of different conformational segments, have been studied. The dynamic properties including the transition modes of gauche migration and gauche-pair creation, which have been reported before in n-alkanes, and the auto- and cross-correlations of the bond dihedral angles, have also been obtained. It was possible to make direct comparisons on some of the statistics with theory and experiment. Most of the results extracted from the molecular dynamics trajectory lie in between previously reported experimental and theoretical values. Many previously predicted conformers have been confirmed by our simulations. The results of the population probability of the most populated conformer seems to suggest that an earlier discrepancy between the theoretical works and an experimental work originates from insufficient samplings in earlier theoretical works, rather than from their inaccurate force field.

Information-theoretic decomposition of embodied and situated systems.

PubMed

Da Rold, Federico

2018-07-01

The embodied and situated view of cognition stresses the importance of real-time and nonlinear bodily interaction with the environment for developing concepts and structuring knowledge. In this article, populations of robots controlled by an artificial neural network learn a wall-following task through artificial evolution. At the end of the evolutionary process, time series are recorded from perceptual and motor neurons of selected robots. Information-theoretic measures are estimated on pairings of variables to unveil nonlinear interactions that structure the agent-environment system. Specifically, the mutual information is utilized to quantify the degree of dependence and the transfer entropy to detect the direction of the information flow. Furthermore, the system is analyzed with the local form of such measures, thus capturing the underlying dynamics of information. Results show that different measures are interdependent and complementary in uncovering aspects of the robots' interaction with the environment, as well as characteristics of the functional neural structure. Therefore, the set of information-theoretic measures provides a decomposition of the system, capturing the intricacy of nonlinear relationships that characterize robots' behavior and neural dynamics. Copyright © 2018 Elsevier Ltd. All rights reserved.

Theoretical and experimental study of fenofibrate and simvastatin

NASA Astrophysics Data System (ADS)

Nicolás Vázquez, Inés; Rodríguez-Núñez, Jesús Rubén; Peña-Caballero, Vicente; Ruvalcaba, Rene Miranda; Aceves-Hernandez, Juan Manuel

2017-12-01

Fenofibrate, an oral fibrate lipid lowering agent, and simvastatin, which reduces plasma levels of low-density lipoprotein cholesterol, are active pharmaceutical ingredients (APIs), currently in the market. We characterized these APIs by thermal analysis and conducted X-ray powder diffraction techniques. Studies should be carried out in the formulation stage before the final composition of a polypill may be established. Thus, it was found in thermochemical studies that both compounds present no chemical interactions in an equimolar mixture of solid samples at room temperature. Theoretical studies were employed to determine possible interactions between fenofibrate and simvastatin. A very weak intramolecular hydrogen bond is formed between the hydroxyl group (O5H5) of the simvastatin with chlorine and carbonyl group (C11O4, C1O2) of the fenofibrate molecule. These weak energy hydrogen bonds have no effect on the chemical stability of the compounds studied. The results were obtained using Density Functional Theory methods; particularly the BPE1BPE and B3LYP functional and 6-31++G** basis set. The values of energy show good approximation when are compared with similar calculations previously reported. Infrared spectra of monomers and dimers were obtained via theoretical calculations.

Theoretical calculation of polarizability isotope effects.

PubMed

Moncada, Félix; Flores-Moreno, Roberto; Reyes, Andrés

2017-03-01

We propose a scheme to estimate hydrogen isotope effects on molecular polarizabilities. This approach combines the any-particle molecular orbital method, in which both electrons and H/D nuclei are described as quantum waves, with the auxiliary density perturbation theory, to calculate analytically the polarizability tensor. We assess the performance of method by calculating the polarizability isotope effect for 20 molecules. A good correlation between theoretical and experimental data is found. Further analysis of the results reveals that the change in the polarizability of a X-H bond upon deuteration decreases as the electronegativity of X increases. Our investigation also reveals that the molecular polarizability isotope effect presents an additive character. Therefore, it can be computed by counting the number of deuterated bonds in the molecule.

Mechanism of Flutter A Theoretical and Experimental Investigation of the Flutter Problem

NASA Technical Reports Server (NTRS)

Theodorsen, Theodore; Garrick, I E

1940-01-01

The results of the basic flutter theory originally devised in 1934 and published as NACA Technical Report no. 496 are presented in a simpler and more complete form convenient for further studies. The paper attempts to facilitate the judgement of flutter problems by a systematic survey of the theoretical effects of the various parameters. A large number of experiments were conducted on cantilever wings, with and without ailerons, in the NACA high-speed wind tunnel for the purpose of verifying the theory and to study its adaptability to three-dimensional problems. The experiments included studies on wing taper ratios, nacelles, attached floats, and external bracings. The essential effects in the transition to the three-dimensional problem have been established. Of particular interest is the existence of specific flutter modes as distinguished from ordinary vibration modes. It is shown that there exists a remarkable agreement between theoretical and experimental results.

Nonequilibrium phase transitions of sheared colloidal microphases: Results from dynamical density functional theory

NASA Astrophysics Data System (ADS)

Stopper, Daniel; Roth, Roland

2018-06-01

By means of classical density functional theory and its dynamical extension, we consider a colloidal fluid with spherically symmetric competing interactions, which are well known to exhibit a rich bulk phase behavior. This includes complex three-dimensional periodically ordered cluster phases such as lamellae, two-dimensional hexagonally packed cylinders, gyroid structures, or spherical micelles. While the bulk phase behavior has been studied extensively in earlier work, in this paper we focus on such structures confined between planar repulsive walls under shear flow. For sufficiently high shear rates, we observe that microphase separation can become fully suppressed. For lower shear rates, however, we find that, e.g., the gyroid structure undergoes a kinetic phase transition to a hexagonally packed cylindrical phase, which is found experimentally and theoretically in amphiphilic block copolymer systems. As such, besides the known similarities between the latter and colloidal systems regarding the equilibrium phase behavior, our work reveals further intriguing nonequilibrium relations between copolymer melts and colloidal fluids with competing interactions.

The need for international nursing diagnosis research and a theoretical framework.

PubMed

Lunney, Margaret

2008-01-01

To describe the need for nursing diagnosis research and a theoretical framework for such research. A linguistics theory served as the foundation for the theoretical framework. Reasons for additional nursing diagnosis research are: (a) file names are needed for implementation of electronic health records, (b) international consensus is needed for an international classification, and (c) continuous changes occur in clinical practice. A theoretical framework used by the author is explained. Theoretical frameworks provide support for nursing diagnosis research. Linguistics theory served as an appropriate exemplar theory to support nursing research. Additional nursing diagnosis studies based upon a theoretical framework are needed and linguistics theory can provide an appropriate structure for this research.

Detection, attribution, and sensitivity of trends toward earlier streamflow in the Sierra Nevada

USGS Publications Warehouse

Maurer, E.P.; Stewart, I.T.; Bonfils, Celine; Duffy, P.B.; Cayan, D.

2007-01-01

Observed changes in the timing of snowmelt dominated streamflow in the western United States are often linked to anthropogenic or other external causes. We assess whether observed streamflow timing changes can be statistically attributed to external forcing, or whether they still lie within the bounds of natural (internal) variability for four large Sierra Nevada (CA) basins, at inflow points to major reservoirs. Streamflow timing is measured by "center timing" (CT), the day when half the annual flow has passed a given point. We use a physically based hydrology model driven by meteorological input from a global climate model to quantify the natural variability in CT trends. Estimated 50-year trends in CT due to natural climate variability often exceed estimated actual CT trends from 1950 to 1999. Thus, although observed trends in CT to date may be statistically significant, they cannot yet be statistically attributed to external influences on climate. We estimate that projected CT changes at the four major reservoir inflows will, with 90% confidence, exceed those from natural variability within 1-4 decades or 4-8 decades, depending on rates of future greenhouse gas emissions. To identify areas most likely to exhibit CT changes in response to rising temperatures, we calculate changes in CT under temperature increases from 1 to 5??. We find that areas with average winter temperatures between -2??C and -4??C are most likely to respond with significant CT shifts. Correspondingly, elevations from 2000 to 2800 in are most sensitive to temperature increases, with CT changes exceeding 45 days (earlier) relative to 1961-1990. Copyright 2007 by the American Geophysical Union.

Metamorphosis Is Ancestral for Crown Euarthropods, and Evolved in the Cambrian or Earlier.

PubMed

Wolfe, Joanna M

2017-09-01

Macroevolutionary developmental biology employs fossilized ontogenetic data and phylogenetic comparative methods to probe the evolution of development at ancient nodes. Despite the prevalence of ecologically differentiated larval forms in marine invertebrates, it has been frequently presumed that the ancestors of arthropods were direct developers, and that metamorphosis may not have evolved until the Ordovician or later. Using fossils and new dated phylogenies, I infer that metamorphosis was likely ancestral for crown arthropods, contradicting this assumption. Based on a published morphological dataset encompassing 217 exceptionally preserved fossil and 96 extant taxa, fossils were directly incorporated into both the topology and age estimates, as in "tip dating" analyses. Using data from post-embryonic fossils representing 25 species throughout stem and crown arthropod lineages (as well as most of the 96 extant taxa), characters for metamorphosis were assigned based on inferred ecological changes in development (e.g., changes in habitat and adaptive landscape). Under all phylogenetic hypotheses, metamorphosis was supported as most likely ancestral to both ecdysozoans and euarthropods. Care must be taken to account for potential drastic post-embryonic morphological changes in evolutionary analyses. Many stem group euarthrpods may have had ecologically differentiated larval stages that did not preserve in the fossil record. Moreover, a complex life cycle and planktonic ecology may have evolved in the Ediacaran or earlier, and may have typified the pre-Cambrian explosion "wormworld" prior to the origin of crown group euarthropods. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Chemistry, physiology and neuropsychology of schizophrenia: towards an earlier diagnosis of schizophrenia I.

PubMed

Kornhuber, H H

1983-01-01

Data supporting the glutamate hypothesis of schizophrenia are presented. The glutamate hypothesis is linked to the dopamine hypothesis by the fact that dopamine synapses inhibit the release of glutamate in the striate and mesolimbic system. The glutamate hypothesis of schizophrenia may open a way to find better drugs for treatment. The concept of schizophrenia I is described. It consists of "negative symptoms" such as disconcentration or reduction of energy. Schizophrenia I precedes and follows schizophrenia II with "positive symptoms," e.g. hallucinations and delusions. Schizophrenia I so far cannot be diagnosed as schizophrenia unless schizophrenia II appears. Chemical, physiological or neuropsychological methods for the diagnosis of schizophrenia I would render an earlier treatment of schizophrenia possible and thus make social and occupational rehabilitation more efficient. An objective diagnosis of schizophrenia I may also elucidate the mode of genetic transmission of schizophrenia. Several neuropsychological methods distinguish schizophrenic patients as a group from normals. Some of them are based on a specific disturbance of long term concentration. The EEG also distinguishes schizophrenics from normals when analyzed during voluntary movement. For schizophrenics it takes more effort to initiate a voluntary movement, and there are several features of the EEG correlated to this. Moreover, the longer motor reaction time of schizophrenics is paralleled by a longer duration of the Bereitschaftspotential in schizophrenia. Furthermore, there is a difference in the theta rhythm between schizophrenic patients and normals in a task which requires concentration. Some of the children of schizophrenic parents show a disturbance of concentration in both reaction time tasks and the d 2 test.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactive 3D visualization for theoretical virtual observatories

NASA Astrophysics Data System (ADS)

Dykes, T.; Hassan, A.; Gheller, C.; Croton, D.; Krokos, M.

2018-06-01

Virtual observatories (VOs) are online hubs of scientific knowledge. They encompass a collection of platforms dedicated to the storage and dissemination of astronomical data, from simple data archives to e-research platforms offering advanced tools for data exploration and analysis. Whilst the more mature platforms within VOs primarily serve the observational community, there are also services fulfilling a similar role for theoretical data. Scientific visualization can be an effective tool for analysis and exploration of data sets made accessible through web platforms for theoretical data, which often contain spatial dimensions and properties inherently suitable for visualization via e.g. mock imaging in 2D or volume rendering in 3D. We analyse the current state of 3D visualization for big theoretical astronomical data sets through scientific web portals and virtual observatory services. We discuss some of the challenges for interactive 3D visualization and how it can augment the workflow of users in a virtual observatory context. Finally we showcase a lightweight client-server visualization tool for particle-based data sets, allowing quantitative visualization via data filtering, highlighting two example use cases within the Theoretical Astrophysical Observatory.

Transitions theory: a trajectory of theoretical development in nursing.

PubMed

Im, Eun-Ok

2011-01-01

There have been very few investigations into how any single nursing theory has actually evolved historically. In this paper, a trajectory of theoretical development in nursing is explored through reviewing the theoretical development of a single nursing theory-transitions theory. The literature related to transitions theory was searched and retrieved using multiple databases. Ninety-nine papers were analyzed according to type of theory, populations of interest, sources of theorizing, and theoretical methods. Transitions theory originated in research but was initially borrowed. It also arose in research with immigrants and from national and international collaborative research efforts. A product of mentoring, transitions theory is used widely in nursing education, research, and practice. Diverse thoughts related to transitions theory coexist. For future theoretical development in nursing, we need to remain open to new ideas and continue to engage in multiple collaborative efforts. Copyright © 2011 Elsevier Inc. All rights reserved.

Theoretical Approaches to Political Communication.

ERIC Educational Resources Information Center

Chesebro, James W.

Political communication appears to be emerging as a theoretical and methodological academic area of research within both speech-communication and political science. Five complimentary approaches to political science (Machiavellian, iconic, ritualistic, confirmational, and dramatistic) may be viewed as a series of variations which emphasize the…

Theoretical Constraints on Properties of Dynamic Ruptures Implied by Pulverized Fault Zone Rocks

NASA Astrophysics Data System (ADS)

Xu, S.; Ben-Zion, Y.

2016-12-01

Prominent belts of Pulverized Fault Zone Rocks (PFZR) have been observed adjacent to several major strike-slip faults that separate different crustal blocks. They consist of 100-200m wide zones of highly damaged rock products, primarily of crystalline origin, that were mechanically shattered to sub-micron scale while preserving most of their original fabric with little evidence of shear. PFZR are strongly asymmetric with respect to the fault trace, existing primarily on the side with higher seismic velocity at depth, and their fabric suggests volumetric deformation with tensile cracks in all directions (e.g., Dor et al., 2006; Rockwell et al., 2009; Mitchell et al., 2011). Generating with split Hopkinson pressure bar in intact cm-scale sample microstructures similar to those observed in PFZR requires strain-rates higher than 150/s (e.g., Doan and Gary, 2009; Yuan et al., 2011). Using samples with preexisting damage reduces the strain-rate required for pulverization by 50% (Doan and d'Hour, 2012). These laboratory observations support earlier suggestions that PFZR are produced by dynamic stress fields at the tip of earthquake ruptures (e.g., Ben-Zion and Shi, 2005; Reches and Dewers, 2005). To clarify the conditions associated with generation of PFZR, we discuss theoretical results based on Linear Elastic Fracture Mechanics and simulations of Mode-II dynamic ruptures on frictional faults (Xu and Ben-Zion, 2016). We consider subshear and supershear ruptures along faults between similar and dissimilar solids. The results indicate that strain-rates higher than 150/s can be generated at distance of about 100m from the fault by either subshear ruptures on a bimaterial interface or supershear ruptures between similar and dissimilar solids. The dynamic fields of subshear bimaterial ruptures are expected to produce off-fault damage primarily on the stiff side of the fault, with tensile cracks that have no preferred orientation, in agreement with observations. In contrast

Analysing Teachers' Practices in Technology Environments from an Activity Theoretical Approach

ERIC Educational Resources Information Center

Abboud-Blanchard, Maha; Vandebrouck, Fabrice

2012-01-01

The aim of this paper is to emphasize some research results about teachers' practices in technology-based-lessons. Articulating several theoretical developments of Activity Theory enables us to conceive a frame to characterise the evolutions of these practices and to interpret them in terms of "geneses of technology uses". We consider these…

Predicting Child Abuse Potential: An Empirical Investigation of Two Theoretical Frameworks

ERIC Educational Resources Information Center

Begle, Angela Moreland; Dumas, Jean E.; Hanson, Rochelle F.

2010-01-01

This study investigated two theoretical risk models predicting child maltreatment potential: (a) Belsky's (1993) developmental-ecological model and (b) the cumulative risk model in a sample of 610 caregivers (49% African American, 46% European American; 53% single) with a child between 3 and 6 years old. Results extend the literature by using a…

Connecting single cell to collective cell behavior in a unified theoretical framework

NASA Astrophysics Data System (ADS)

George, Mishel; Bullo, Francesco; Campàs, Otger

Collective cell behavior is an essential part of tissue and organ morphogenesis during embryonic development, as well as of various disease processes, such as cancer. In contrast to many in vitro studies of collective cell migration, most cases of in vivo collective cell migration involve rather small groups of cells, with large sheets of migrating cells being less common. The vast majority of theoretical descriptions of collective cell behavior focus on large numbers of cells, but fail to accurately capture the dynamics of small groups of cells. Here we introduce a low-dimensional theoretical description that successfully captures single cell migration, cell collisions, collective dynamics in small groups of cells, and force propagation during sheet expansion, all within a common theoretical framework. Our description is derived from first principles and also includes key phenomenological aspects of cell migration that control the dynamics of traction forces. Among other results, we explain the counter-intuitive observations that pairs of cells repel each other upon collision while they behave in a coordinated manner within larger clusters.

Theoretical Borderlands: Using Multiple Theoretical Perspectives to Challenge Inequitable Power Structures in Student Development Theory

ERIC Educational Resources Information Center

Abes, Elisa S.

2009-01-01

This article is an exploration of possibilities and methodological considerations for using multiple theoretical perspectives in research that challenges inequitable power structures in student development theory. Specifically, I explore methodological considerations when partnering queer theory and constructivism in research on lesbian identity…

Earlier onset of motor deficits in mice with double mutations in Dyt1 and Sgce.

PubMed

Yokoi, Fumiaki; Yang, Guang; Li, Jindong; DeAndrade, Mark P; Zhou, Tong; Li, Yuqing

2010-10-01

DYT1 early-onset generalized torsion dystonia is an inherited movement disorder caused by mutations in DYT1 coding for torsinA with ∼30% penetrance. Most of the DYT1 dystonia patients exhibit symptoms during childhood and adolescence. On the other hand, DYT1 mutation carriers without symptoms during these periods mostly do not exhibit symptoms later in their life. Little is known about what controls the timing of the onset, a critical issue for DYT1 mutation carriers. DYT11 myoclonus-dystonia is caused by mutations in SGCE coding for ε-sarcoglycan. Two dystonia patients from a single family with double mutations in DYT1 and SGCE exhibited more severe symptoms. A recent study suggested that torsinA contributes to the quality control of ε-sarcoglycan. Here, we derived mice carrying mutations in both Dyt1 and Sgce and found that these double mutant mice showed earlier onset of motor deficits in beam-walking test. A novel monoclonal antibody against mouse ε-sarcoglycan was developed by using Sgce knock-out mice to avoid the immune tolerance. Western blot analysis suggested that functional deficits of torsinA and ε-sarcoglycan may independently cause motor deficits. Examining additional mutations in other dystonia genes may be beneficial to predict the onset in DYT1 mutation carriers.

Theoretical Studies of Liquid He-4 Near the Superfluid Transition

NASA Technical Reports Server (NTRS)

Manousakis, Efstratios

2002-01-01

We performed theoretical studies of liquid helium by applying state of the art simulation and finite-size scaling techniques. We calculated universal scaling functions for the specific heat and superfluid density for various confining geometries relevant for experiments such as the confined helium experiment and other ground based studies. We also studied microscopically how the substrate imposes a boundary condition on the superfluid order parameter as the superfluid film grows layer by layer. Using path-integral Monte Carlo, a quantum Monte Carlo simulation method, we investigated the rich phase diagram of helium monolayer, bilayer and multilayer on a substrate such as graphite. We find excellent agreement with the experimental results using no free parameters. Finally, we carried out preliminary calculations of transport coefficients such as the thermal conductivity for bulk or confined helium systems and of their scaling properties. All our studies provide theoretical support for various experimental studies in microgravity.