Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
1.
Nature ; 615(7953): 614-619, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36949338

RESUMEN

Early experiments with transiting circular Rydberg atoms in a superconducting resonator laid the foundations of modern cavity and circuit quantum electrodynamics1, and helped explore the defining features of quantum mechanics such as entanglement. Whereas ultracold atoms and superconducting circuits have since taken rather independent paths in the exploration of new physics, taking advantage of their complementary strengths in an integrated system enables access to fundamentally new parameter regimes and device capabilities2,3. Here we report on such a system, coupling an ensemble of cold 85Rb atoms simultaneously to an, as far as we are aware, first-of-its-kind optically accessible, three-dimensional superconducting resonator4 and a vibration-suppressed optical cavity in a cryogenic (5 K) environment. To demonstrate the capabilities of this platform, and with an eye towards quantum networking5, we leverage the strong coupling between Rydberg atoms and the superconducting resonator to implement a quantum-enabled millimetre wave (mmwave) photon to optical photon transducer6. We measured an internal conversion efficiency of 58(11)%, a conversion bandwidth of 360(20) kHz and added thermal noise of 0.6 photons, in agreement with a parameter-free theory. Extensions of this technique will allow near-unity efficiency transduction in both the mmwave and microwave regimes. More broadly, our results open a new field of hybrid mmwave/optical quantum science, with prospects for operation deep in the strong coupling regime for efficient generation of metrologically or computationally useful entangled states7 and quantum simulation/computation with strong non-local interactions8.

2.
Emerg Med J ; 41(1): 51-59, 2023 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-37827821

RESUMEN

BACKGROUND: Health coaching services could help to reduce emergency healthcare utilisation for patients targeted proactively by a clinical prediction model (CPM) predicting patient likelihood of future hospitalisations. Such interventions are designed to empower patients to confidently manage their own health and effectively utilise wider resources. Using CPMs to identify patients, rather than prespecified criteria, accommodates for the dynamic hospital user population and for sufficient time to provide preventative support. However, it is unclear how this care model would negatively impact survival. METHODS: Emergency Department (ED) attenders and hospital inpatients between 2015 and 2019 were automatically screened for their risk of hospitalisation within 6 months of discharge using a locally trained CPM on routine data. Those considered at risk and screened as suitable for the intervention were contacted for consent and randomised to one-to-one telephone health coaching for 4-6 months, led by registered health professionals, or routine care with no contact after randomisation. The intervention involved motivational guidance, support for self-care, health education, and coordination of social and medical services. Co-primary outcomes were emergency hospitalisation and ED attendances, which will be reported separately. Mortality at 24 months was a safety endpoint. RESULTS: Analysis among 1688 consented participants (35% invitation rate from the CPM, median age 75 years, 52% female, 1139 intervention, 549 control) suggested no significant difference in overall mortality between treatment groups (HR (95% CI): 0.82 (0.62, 1.08), pr(HR<1=0.92), but did suggest a significantly lower mortality in men aged >75 years (HR (95% CI): 0.57 (0.37, 0.84), number needed to treat=8). Excluding one site unable to adopt a CPM indicated stronger impact for this patient subgroup (HR (95% CI): 0.45 (0.26, 0.76)). CONCLUSIONS: Early mortality in men aged >75 years may be reduced by supporting individuals at risk of unplanned hospitalisation with a clear outreach, out-of-hospital nurse-led, telephone-based coaching care model.


Asunto(s)
Modelos Estadísticos , Atención Secundaria de Salud , Masculino , Humanos , Femenino , Anciano , Pronóstico , Hospitalización , Alta del Paciente
3.
Sensors (Basel) ; 22(18)2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-36146352

RESUMEN

This two-experiment study aimed to examine the effects of different habitual foot placement angles and also the effects of manipulating the foot placement angle on the kinetics, three-dimensional kinematics and muscle forces of the squat. In experiment 1, seventy lifters completed squats at 70% of their one repetition maximum using a self-preferred placement angle. They were separated based on their habitual foot angle into three groups HIGH, MEDIUM and LOW. In experiment 2, twenty lifters performed squats using the same relative mass in four different foot placement angle conditions (0°, 21°, 42° and control). Three-dimensional kinematics were measured using an eight-camera motion analysis system, ground reaction forces (GRF) using a force platform, and muscle forces using musculoskeletal modelling techniques. In experiment 1, the impulse of the medial GRF, in the descent and ascent phases, was significantly greater in the HIGH group compared to LOW, and in experiment 2 statistically greater in the 42° compared to the 21°, 0° and control conditions. Experiment 2 showed that the control condition statistically increased quadriceps muscle forces in relation to 0°, whereas the 0° condition significantly enhanced gluteus maximus, gastrocnemius and soleus forces compared to control. In experiment 1, patellofemoral joint stress was significantly greater in the HIGH group compared to LOW, and in experiment 2, patellar and patellofemoral loading were statistically greater in the control compared to the 42°, 21°, 0° and control conditions. Owing to the greater medial GRF's, increased foot placement angles may improve physical preparedness for sprint performance and rapid changes of direction. Reducing the foot angle may attenuate the biomechanical mechanisms linked to the aetiology of knee pathologies and to promote gluteus maximus, gastrocnemius and soleus muscular development. As such, though there does not appear to be an optimal foot placement angle, the observations from this study can be utilised by both strength and conditioning and sports therapy practitioners seeking to maximise training and rehabilitative adaptations.


Asunto(s)
Pie , Postura , Fenómenos Biomecánicos , Humanos , Articulación de la Rodilla/fisiología , Extremidad Inferior , Masculino , Músculo Esquelético/fisiología , Postura/fisiología
4.
Opt Lett ; 46(1): 21-24, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33362003

RESUMEN

Low-loss conversion among a complete and orthogonal set of optical modes is important for high-bandwidth quantum and classical communication. In this Letter, we explore tunable impedance mismatch between coupled Fabry-Perot resonators as a powerful tool for manipulation of the spatial and temporal properties of optical fields. In the single-mode regime, frequency-dependent impedance matching enables tunable finesse optical resonators. Introducing the spatial dependence of the impedance mismatch enables coherent spatial mode conversion of optical photons at near-unity efficiency. We experimentally demonstrate a NIR resonator whose finesse is tunable over a decade, and an optical mode converter with efficiency >75% for the first six Hermite-Gauss modes. We anticipate that this new perspective on coupled multimode resonators will have exciting applications in micro- and nano-photonics and computer-aided inverse design.

5.
J Appl Meas ; 21(1): 1-16, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32129766

RESUMEN

Rasch's logistic model for growth is explained by reviewing his analysis of piglet growth. An early formulation was given in India when Rasch visited with Rao to describe the statistic metameter as the distinguishing characteristic for determining the rate of growth. Next, several examples are given demonstrating growth with plots of growth over time using characteristic time with truncated data. The results of these growth plots and analyses are summarized given their implications and restraints for using this approach in determining rate of growth.


Asunto(s)
Modelos Logísticos , India , Psicometría
6.
J Appl Meas ; 20(2): 123-133, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31120430

RESUMEN

Loevinger's specifications for a unidimensional test are discussed. The implications are reviewed using commentary from Guttman's and Rasch's specification for specific objectivity. A large population is sampled to evaluate the implications of this approach in light of Wright's early presentation regarding data analysis. The results of this analysis show the sample follows the specifications of Loevinger and those of Rasch for a unidimensional test.


Asunto(s)
Pruebas Psicológicas , Psicometría
7.
Eur J Appl Physiol ; 118(2): 339-347, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29214462

RESUMEN

PURPOSE: Isometric exercise (IE) has been shown to lower blood pressure (BP). Using equipment with force output displays, intensity is usually regulated at 30% maximal voluntary contraction (MVC); however, the cost of programmable equipment and their requirement for maximal contractions presents limitations. A simple, cost-effective alternative deserves investigation. The purpose of this study was (1) to explore the relationship between %MVC, change in systolic BP (ΔSBP), and perceived exertion (CR-10) and (2) to assess the validity of self-regulation of intensity during isometric hand-grip exercise. METHODS: Fourteen pre-hypertensive and hypertensive adults completed eight, 2-min isometric hand-grip exercises at randomised intensities; participants estimated their perceived exertion at 30-s intervals (estimation task). Subsequently, on three separate occasions, participants performed four 2-min contractions at an exertion level that they perceived to be equivalent to CR-10 "Level-6" (production task). RESULTS: There were significant linear relationships between the estimated exertion on the CR-10 scale, and ΔSBP (r = 0.784) and %MVC (r = 0.845). Level-6 was equivalent to an average ΔSBP of 38 mmHg (95% CI; 44, 32 mmHg) and a relative force of 33% MVC (95% CI; 36.2, 30%). During the production task, %MVC was not significantly different between the estimation task and each production trial. In at least the first two repetitions of each production trial, ΔSBP was significantly lower than that observed in the estimation task. CONCLUSION: These findings show that CR-10 "Level-6" is an appropriate method of self-regulating isometric hand-grip intensity; its use offers an affordable and accessible alternative for isometric exercise prescription aimed at reducing BP.


Asunto(s)
Terapia por Ejercicio/métodos , Fuerza de la Mano , Hipertensión/terapia , Contracción Isométrica , Esfuerzo Físico , Anciano , Terapia por Ejercicio/normas , Femenino , Humanos , Hipertensión/prevención & control , Masculino , Persona de Mediana Edad , Percepción , Distribución Aleatoria , Estándares de Referencia
8.
Environ Manage ; 62(2): 352-364, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-29654363

RESUMEN

Water managers are increasingly using environmental flows (e-flows) as a tool to improve ecological conditions downstream from impoundments. Recent studies have called for e-flow approaches that explicitly consider impacts on hydrogeomorphic processes when developing management alternatives. Process-based approaches are particularly relevant in river systems that have been highly modified and where water supplies are over allocated. One-dimensional (1D) and two-dimensional (2D) hydrodynamic models can be used to resolve hydrogeomorphic processes at different spatial and temporal scales to support the development, testing, and refinement of e-flow hypotheses. Thus, the objective of this paper is to demonstrate the use of hydrodynamic models as a tool for assisting stakeholders in targeting and assessing environmental flows within a decision-making framework. We present a case study of e-flows on the Rio Chama in northern New Mexico, USA, where 1D and 2D hydrodynamic modeling was used within a collaborative process to implement an e-flow experiment. A specific goal of the e-flow process was to improve spawning habitat for brown trout by flushing fine sediments from gravel features. The results revealed that the 2D hydrodynamic model provided much greater insight with respect to hydrodynamic and sediment transport processes, which led to a reduction in the recommended e-flow discharge. The results suggest that 2D hydrodynamic models can be useful tools for improving process understanding, developing e-flow recommendations, and supporting adaptive management even when limited or no data are available for model calibration and validation.


Asunto(s)
Monitoreo del Ambiente/métodos , Hidrodinámica , Modelos Teóricos , Ríos/química , Abastecimiento de Agua/métodos , Ecología , New Mexico , Movimientos del Agua
9.
Ecol Soc ; 22(1): 1-31, 2017 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-29780427

RESUMEN

In this article we summarize histories of nonlinear, complex interactions among societal, legal, and ecosystem dynamics in six North American water basins, as they respond to changing climate. These case studies were chosen to explore the conditions for emergence of adaptive governance in heavily regulated and developed social-ecological systems nested within a hierarchical governmental system. We summarize resilience assessments conducted in each system to provide a synthesis and reference by the other articles in this special feature. We also present a general framework used to evaluate the interactions between society and ecosystem regimes and the governance regimes chosen to mediate those interactions. The case studies show different ways that adaptive governance may be triggered, facilitated, or constrained by ecological and/or legal processes. The resilience assessments indicate that complex interactions among the governance and ecosystem components of these systems can produce different trajectories, which include patterns of (a) development and stabilization, (b) cycles of crisis and recovery, which includes lurches in adaptation and learning, and (3) periods of innovation, novelty, and transformation. Exploration of cross scale (Panarchy) interactions among levels and sectors of government and society illustrate that they may constrain development trajectories, but may also provide stability during crisis or innovation at smaller scales; create crises, but may also facilitate recovery; and constrain system transformation, but may also provide windows of opportunity in which transformation, and the resources to accomplish it, may occur. The framework is the starting point for our exploration of how law might play a role in enhancing the capacity of social-ecological systems to adapt to climate change.

10.
J Acoust Soc Am ; 136(6): 3028, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25480052

RESUMEN

In corrosion assessment, ultrasonic wall-thickness measurements are often presented in the form of a color map. However, this gives little quantitative information on the distribution of the thickness measurements. The collected data can be used to form an empirical cumulative distribution function (ECDF), which provides information on the fraction of the surface with less than a certain thickness. It has been speculated that the ECDF could be used to draw conclusions about larger areas, from inspection data of smaller sub-sections. A detailed understanding of the errors introduced by such an approach is required to be confident in its predictions. There are two major sources of error: the actual thickness variation due to the morphology of the surface and the interaction of the signal processing algorithm with the recorded ultrasonic signals. Parallel experimental and computational studies were performed using three surfaces, generated with Gaussian height distributions. The surfaces were machined onto mild steel plates and ultrasonic C-scans were performed, while the distributed point source method was used to perform equivalent simulations. ECDFs corresponding to each of these surfaces (for both the experimental and computational data) are presented and their variation with changing surface roughness and different timing algorithms is discussed.

11.
J Appl Meas ; 15(1): 26-39, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24518579

RESUMEN

Several concepts from Georg Rasch's last papers are discussed. The key one is comparison because Rasch considered the method of comparison fundamental to science. From the role of comparison stems scientific inference made operational by a properly developed frame of reference producing specific objectivity. The exact specifications Rasch outlined for making comparisons are explicated from quotes, and the role of causality derived from making comparisons is also examined. Understanding causality has implications for what can and cannot be produced via Rasch measurement. His simple examples were instructive, but the implications are far reaching upon first establishing the key role of comparison.


Asunto(s)
Modelos Estadísticos , Psicometría/estadística & datos numéricos , Ciencia/estadística & datos numéricos , Interpretación Estadística de Datos , Humanos , Reproducibilidad de los Resultados , Investigación/estadística & datos numéricos
12.
Eur J Appl Physiol ; 113(12): 3001-10, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24085485

RESUMEN

PURPOSE: Previous research has suggested that the optimal pacing strategy for self-paced exercise lasting >4 min is a uniform distribution of work, but this posit is not well established for prolonged endurance events. This study examined the utility of even pacing during 20 km cycling time trials (TTs). METHODS: Fifteen well-trained male cyclists ([Formula: see text]O2max = 4.80 ± 0.38 L min(-1)) completed three best effort self-paced (SP) simulated 20 km TTs, followed by two even-paced trials. In one even-paced trial, participants cycled to exhaustion (EPtlim) at a fixed intensity equivalent to their best SP performance. In the other EP trial, participants were instructed to maintain this target intensity for a distance of 20 km, but the actual intensity was free to vary depending on the effort and cadence of the cyclist (EP-maintained). Cardiorespiratory, blood lactate and perceptual (RPE and affect) measures were assessed throughout. RESULTS: Nine out of fifteen cyclists failed the EPtlim task, completing 51-83 % (10.3-15.3 km) of the work done in their SP trial. Failure as a result of even pacing was associated with a faster rise in blood lactate, attainment of a higher relative intensity during SP and a moderate fast starting strategy. This failure was independent of the nature of the even-paced task. CONCLUSION: By adopting an uneven, parabolic distribution of work, cyclists in this study were able to achieve an average intensity during self-paced exercise in excess of their maximum sustainable power output. A subsequent matched even-paced bout resulted in cumulative metabolic stress that could not be managed by moment-to-moment changes in power output. These results challenge the notion that strict even pacing is optimal for endurance time trial events.


Asunto(s)
Tolerancia al Ejercicio , Ejercicio Físico , Adulto , Atletas , Rendimiento Atlético , Estudios de Casos y Controles , Humanos , Masculino , Factores de Tiempo
13.
Rev Sci Instrum ; 94(8)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38065169

RESUMEN

Cavity quantum electrodynamics (QED), the study of the interaction between quantized emitters and photons confined in an optical cavity, is an important tool for quantum science in computing, networking, and synthetic matter. In atomic cavity QED, this approach typically relies upon an ultrahigh vacuum chamber that hosts a cold trapped atomic ensemble and an optical cavity. Upgrading the cavity necessitates a months-long laborious process of removing external optics, venting, replacing the resonator, baking, and replacing optics, constituting a substantial bottleneck to innovation in resonator design. In this work, we demonstrate that the flexibility of optical cavities and the quick turnaround time in switching between them can be restored with the vacuum loadlock technique-reducing the cycle time to install a cavity, bake it, and transport it into the science chamber for days, achieving 3 × 10-10 Torr pressure in the science chamber. By reducing vacuum limitations, this approach is particularly powerful for labs interested in quickly exploring novel optic cavities or any other atomic physics relying on in-vacuum optics.

14.
Eur J Appl Physiol ; 112(1): 223-9, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21533808

RESUMEN

The aim of the study was to assess the reproducibility of pacing strategy, physiological and perceptual responses during simulated 20-km cycling time trials. Seventeen well-trained male cyclists ([Formula: see text] = 4.70 ± 0.33 L min(-1)) completed three 20-km time trials on a Velotron Pro cycle ergometer within a maximum duration of 14 days. During all trials power output, cadence and respiratory exchange were recorded throughout, rating of perceived exertion and affective response were recorded every 2-km and capillary blood was sampled and assayed for the determination of lactate concentration every 4-km. Power output data was assigned to 1-km 'bins' and expressed relative to the mean to quantify pacing strategy. Reproducibility of the pacing strategy and the whole trial mean responses was subsequently quantified using typical error (TE) with 90% confidence intervals. The pacing strategy adopted was similar across repeat trials, though there was a higher degree of variability at the start and end of the trial (TE = 6.6 and 6.8% for the first and last 1-km), and a trend for a progressively blunted start on repeat trials. The reproducibility of performance, cardiorespiratory and perceptual measures was good (TE range 1.0-4.0%), but blood lactate exhibited higher variability (TE = 17.7%). The results demonstrate the performance, perceptual and physiological response to self-paced 20-km time trials is reproducible in well-trained cyclists. Future research should acknowledge that variability in pacing strategy at the start and end of a self-paced bout is likely regardless of any intervention employed.


Asunto(s)
Ciclismo/fisiología , Modelos Biológicos , Esfuerzo Físico/fisiología , Aptitud Física/fisiología , Desempeño Psicomotor/fisiología , Adulto , Humanos , Masculino , Sensibilidad y Especificidad
15.
Eur J Appl Physiol ; 112(8): 3069-78, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22194003

RESUMEN

It has been proposed that an even-pacing strategy is optimal for events lasting <120 s, but this assertion is not well-established. This study tested the hypothesis that even-paced cycling is less challenging than self- or variable-paced cycling. Ten well-trained male cyclists (VO2max, 4.89 ± 0.32 L min(-1)) completed a self-paced (SP) 20-km time trial followed by time- and work-matched even-paced (EP 100% SP mean power) and variable-paced (VP 142 and 72% SP mean power, 1:1.5 high:low power ratio) trials in a random, counterbalanced order. During all trials expired air and heart rate were analysed throughout, blood lactate was sampled every 4 km, and perceptual responses (rating of perceived exertion (RPE) and affect) were assessed every 2 km and post-trial. There were no whole trial statistically significant differences between trials for any of the respiratory variables measured, although there was a trend for higher RER's in VP compared to EP (P = 0.053). Blood lactate was lower in EP compared to VP (P = 0.001) and SP (P = 0.001), and higher in SP compared to VP (P = 0.008). RPE was lower, and affect more positive, in EP compared to both SP and VP (P > 0.05). The results of this study show that, for a time- and work-matched 20-km time trial, an even-paced strategy results in attenuated perturbations in the physiological response and lower perception of effort in comparison to self- and variable-paced strategies.


Asunto(s)
Ciclismo/psicología , Contracción Muscular , Músculo Esquelético/fisiología , Percepción , Resistencia Física , Adulto , Análisis de Varianza , Biomarcadores/sangre , Estudios Cruzados , Inglaterra , Prueba de Esfuerzo , Frecuencia Cardíaca , Humanos , Ácido Láctico/sangre , Masculino , Músculo Esquelético/metabolismo , Consumo de Oxígeno , Respiración , Factores de Tiempo
16.
Eur J Appl Physiol ; 111(8): 1807-13, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21222130

RESUMEN

Although pacing-related research is widely reported, no studies have described the consistency of pacing strategies or their associated energetic contributions. This study aimed to investigate the consistency of pacing and energetic outlay by establishing the typical within and between trial variations during simulated 4,000 m time trials. Fifteen well-trained male cyclists performed three, 4,000 m time trials with 3-7 days separating each trial. Power output, cadence, heart rate, respiratory exchange and iEMG of the vastus lateralis were recorded continuously throughout each trial. To examine within-trial variability, the data were assigned to 10% bins. Rating of perceived exertion and affective response were recorded every 400 m and a capillary blood sample was collected and assayed for blood lactate concentration every 800 m. Mean typical error across trials 1-3 for all variables was low (range 2.1-6.3%) and lower between trials 2-3 for all variables with the exception of cadence. There were no between-trial differences in pacing strategy; however, typical error for each 10% bin was lower between trials 2-3 than trials 1-2. Anaerobic contribution to power was greatest during the first and last 10% of each trial (p > 0.05). In conclusion, well-trained cyclists demonstrated a high degree of consistency in terms of the pacing strategy they adopted which coincided with similar levels of energy distribution and perceived exertion. A laboratory simulated 4-km cycling trial is a reliable test that may be used to monitor performance and pacing strategy.


Asunto(s)
Ciclismo/fisiología , Metabolismo Energético/fisiología , Prueba de Esfuerzo/métodos , Percepción , Adaptación Fisiológica/fisiología , Adulto , Rendimiento Atlético/fisiología , Simulación por Computador , Humanos , Laboratorios , Masculino , Percepción/fisiología , Análisis y Desempeño de Tareas , Factores de Tiempo
17.
J Gen Psychol ; 138(2): 94-109, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21560467

RESUMEN

Anagrams are frequently used by experimental psychologists interested in how the mental lexicon is organized. Until very recently, research has overlooked the importance of syllable structure in solving anagrams and assumed that solution difficulty was mainly due to frequency factors (e.g., bigram statistics). The present study uses Rasch analysis to demonstrate that the number of syllables is a very important factor influencing anagram solution difficulty for both good and poor problem solvers, with polysyllabic words being harder to solve. Furthermore, it suggests that syllable frequency may have an impact on solution times for polysyllabic words, with more frequent syllables being more difficult to solve. The study illustrates the advantages of Rasch analysis for reliable and unidimensional measurement of item difficulty.


Asunto(s)
Solución de Problemas/fisiología , Psicolingüística/métodos , Cognición/fisiología , Humanos , Probabilidad , Pruebas Psicológicas/estadística & datos numéricos , Estudiantes/psicología
18.
J Appl Meas ; 11(3): 244-52, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20847473

RESUMEN

We argue that a goal of measurement is general objectivity: point estimates of a person's measure (height, temperature, and reader ability) should be independent of the instrument and independent of the sample in which the person happens to find herself. In contrast, Rasch's concept of specific objectivity requires only differences (i.e., comparisons) between person measures to be independent of the instrument. We present a canonical case in which there is no overlap between instruments and persons: each person is measured by a unique instrument. We then show what is required to estimate measures in this degenerate case. The canonical case encourages a simplification and reconceptualization of validity and reliability. Not surprisingly, this reconceptualization looks a lot like the way physicists and chemometricians think about validity and measurement error. We animate this presentation with a technology that blurs the distinction between instruction, assessment, and generally objective measurement of reader ability. We encourage adaptation of this model to health outcomes measurement.


Asunto(s)
Temperatura Corporal , Evaluación de Resultado en la Atención de Salud/estadística & datos numéricos , Lectura , Bioestadística , Humanos
19.
Sci Total Environ ; 407(2): 770-5, 2009 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-18973926

RESUMEN

The purpose of this project was to compare the ability of chlorine (HOCl/OCl(-)) and monochloramine (NH(2)Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 microm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L (n=25, SD=0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L (n=25, SD=1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L (n=25, SD=0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L (n=25, SD=0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.


Asunto(s)
Cloraminas/química , Cloro/química , Amalgama Dental/química , Desinfectantes Dentales/química , Residuos Dentales/análisis , Mercurio/análisis , Contaminación Química del Agua/análisis , Mercurio/aislamiento & purificación , Espectrofotometría , Eliminación de Residuos Líquidos
20.
J Relig Health ; 48(3): 305-16, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19639419

RESUMEN

Psychologists sometimes minimize important resources such as religion and spiritual beliefs for coping with bereavement. Alienation of therapeutic psychology from religious values contrasts to professional and public interest in religious experience and commitment. A supportive viewpoint has come about partially as a result of recognizing important values which clinicians have found absent in many of their clients. Until spiritual belief systems become integrated into the work of clinicians, clients may not be fully integrative in coping with loss. The key finding of this study was that individuals who participated in Christian and secular support groups showed no statistically significant difference in their mean endorsement of negative criteria on the BHS, and no statistically significant difference for their mean score endorsement of positive criteria on the RCOPE. However, a Christian-oriented approach was no less effective than a psychological-oriented one. In both groups, a spiritual connection to a specific or generalized higher power was frequently identified which clients ascribed to facilitating the management of their coping.


Asunto(s)
Adaptación Psicológica , Aflicción , Cristianismo , Grupos de Autoayuda , Adulto , Anciano , Anciano de 80 o más Años , Actitud Frente a la Muerte , Femenino , Humanos , Masculino , Persona de Mediana Edad , Espiritualidad , Adulto Joven
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda