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1.
Memory ; 31(5): 665-677, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36945870

RESUMEN

Prospective memory (PM) - memory for future intentions - has a core term called focality which describes how closely a PM task relates to an ongoing task. When a close relationship exists between an ongoing and PM task, the task is classified as focal (loose relationships are classified as nonfocal). Competing PM theories differ primarily in explanations for how focality changes participants' approaches. Researchers classify PM intentions as focal or nonfocal in two ways: (1) task appropriateness, congruency (TAP) or incongruency (TIP) of processing to complete both tasks, and (2) cue specificity, specific or general task cues. Independently manipulating this ambiguity in defining "focality" was our current focus. Participants were randomly assigned to a control group, a focal PM condition, or one of three nonfocal conditions. Their ongoing task involved a semantic judgment (Experiment 1) or an orthographic judgment (Experiment 2). Cue specificity impacted PM accuracy consistently, favouring specific cues. Task-appropriateness impacted PM accuracy in Experiment 1, but not in Experiment 2 which showed protective effects for specific, whole-word PM cues - emphasizing the role that deeper processing has on PM success. These studies highlight the ambiguity in the operational definition of focality and provide the groundwork for continued refinement of the definition.


Asunto(s)
Señales (Psicología) , Memoria Episódica , Humanos , Tiempo de Reacción , Trastornos de la Memoria , Semántica
2.
J Cardiovasc Magn Reson ; 24(1): 2, 2022 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-34980185

RESUMEN

BACKGROUND: Despite the growing utility of cardiovascular magnetic resonance (CMR) for cardiac morphology and function, sex and age-specific normal reference values derived from large, multi-ethnic data sets are lacking. Furthermore, most available studies use a simplified tracing methodology. Using a large cohort of participants without history of cardiovascular disease (CVD) or risk factors from the Canadian Alliance for Healthy Heart and Minds, we sought to establish a robust set of reference values for ventricular and atrial parameters using an anatomically correct contouring method, and to determine the influence of age and sex on ventricular parameters. METHODS AND RESULTS: Participants (n = 3206, 65% females; age 55.2 ± 8.4 years for females and 55.1 ± 8.8 years for men) underwent CMR using standard methods for quantitative measurements of cardiac parameters. Normal ventricular and atrial reference values are provided: (1) for males and females, (2) stratified by four age categories, and (3) for different races/ethnicities. Values are reported as absolute, indexed to body surface area, or height. Ventricular volumes and mass were significantly larger for males than females (p < 0.001). Ventricular ejection fraction was significantly diminished in males as compared to females (p < 0.001). Indexed left ventricular (LV) end-systolic, end-diastolic volumes, mass and right ventricular (RV) parameters significantly decreased as age increased for both sexes (p < 0.001). For females, but not men, mean LV and RVEF significantly increased with age (p < 0.001). CONCLUSION: Using anatomically correct contouring methodology, we provide accurate sex and age-specific normal reference values for CMR parameters derived from the largest, multi-ethnic population free of CVD to date. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02220582. Registered 20 August 2014-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02220582 .


Asunto(s)
Ventrículos Cardíacos , Función Ventricular Izquierda , Factores de Edad , Canadá , Femenino , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Imagen por Resonancia Cinemagnética , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Valores de Referencia , Factores Sexuales , Volumen Sistólico
3.
Mem Cognit ; 50(1): 112-128, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34184211

RESUMEN

Remembering to fulfill an intention at a later time often requires people to monitor the environment for cues that it is time to act. This monitoring involves the strategic allocation of attentional resources, ramping attention up more in some contexts than others. In addition to interfering with ongoing task performance, flexibly shifting attention may affect whether task-irrelevant information is later remembered. In the present investigation, we manipulated contextual expectations in event-related prospective memory (PM) to examine the consequences of flexible attention allocation on incidental memory. Across two experiments, participants completed a color-matching task while monitoring for ill-defined (Experiment 1) or specific (Experiment 2) PM targets. To manipulate contextual expectations, some participants were explicitly told about the trial types in which PM targets could (or not) appear, while others were given less precise or no expectations. Across experiments, participants' color-matching decisions were slower in high-expectation trials, relative to trials when targets were not expected. Additionally, participants had better incidental memory for PM-irrelevant items from high-expectation trials, but only when they received explicit contextual expectations. These results confirm that participants flexibly allocate attention based on explicit trial-by-trial expectations. Furthermore, the present study indicates that greater attention to item identity yields better incidental memory even for PM-irrelevant items, irrespective of processing time.


Asunto(s)
Memoria Episódica , Señales (Psicología) , Humanos , Intención , Recuerdo Mental , Análisis y Desempeño de Tareas
4.
Mem Cognit ; 49(8): 1555-1567, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-33959893

RESUMEN

Although false memories have largely been examined with the Deese-Roediger-McDermott (DRM) paradigm, little research has focused on the semantic context in which associates are encoded. Across three experiments, we varied semantic context during a sentence-processing task with DRM associates embedded within sentences. More meaningful sentences resulted in greater memory errors (Experiment 1). Furthermore, providing contextual information to discriminate old from new items did not reduce false alarms relative to encoding words in isolation when sentences converged on the meaning of the critical lure (Experiment 2), and actually increased memory errors (Experiment 3). These results suggest that semantic context that allows for meaningful relational processing of items within-lists and that converge on the semantic meaning of the critical lure increases the likelihood that the list theme is identified, resulting in more errors at test.


Asunto(s)
Recuerdo Mental , Semántica , Humanos , Memoria , Probabilidad , Represión Psicológica
5.
Mem Cognit ; 47(5): 923-935, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30783910

RESUMEN

Prospective memory (PM) is typically measured using keypresses in laboratory paradigms, which therefore assess only discrete, stage-like processes. In the present study we manipulated focal and nonfocal PM cue conditions, as well as participants' focus on different aspects of the PM/ongoing task set, using the methodology to capture dynamic computer mouse movements. The software captured mouse trajectories during lexical decisions and PM responses. We replicated many findings typical in the PM literature, including the accuracy advantage for focal over nonfocal conditions and longer ongoing-task response times for nonfocal conditions. Participants' movement trajectories during PM responses revealed evidence for both spontaneous-retrieval and strategic-monitoring processes in focal and nonfocal PM retrieval conditions. During trials suggestive of spontaneous retrieval, mouse trajectories initially went toward the typical ongoing-task response but turned mid-trajectory toward the PM response field on the opposite side of the computer screen. In nonfocal conditions, these trajectory reversals had a wider arc and took longer to complete, reflecting the likely greater retrospective retrieval requirements of nonfocal conditions. Regarding what are more likely to be strategic-monitoring processes, a significant portion of responses traveled directly to the PM response field, as though people were prepared to make such a response.


Asunto(s)
Memoria Episódica , Recuerdo Mental/fisiología , Desempeño Psicomotor/fisiología , Adulto , Humanos , Adulto Joven
6.
Exp Aging Res ; 45(1): 28-40, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30707652

RESUMEN

Background/Study Context. Adaptation to normative age-related declines in memory is an important but understudied aspect of successful aging. The purpose of the present study was to shed new light on memory self-efficacy and beliefs about memory and aging as two integral aspects of adult cognition with relevance to successful aging. METHODS: Young (19 to 27 years) and community-dwelling older adults (60 to 94 years) from the Louisiana Healthy Aging Study (LHAS) completed an adapted Memory Functioning Questionnaire (MFQ) which includes a memory self-efficacy subscale, the Memory Controllability Inventory (MCI), and the Aging Concerns Scale (ACS). RESULTS: Nonagenarians' self-reported memory and beliefs about memory and aging were of central interest. We compared their responses to three younger reference groups to examine hypothesized differences in self-reported memory and beliefs about memory and aging in very late life. Results yielded age effects for most of the MFQ and MCI subscales demonstrating more positive subjective views about memory functioning and control over memory for the young adults. Correlation and regression analyses were conducted to isolate factors that may be associated with memory self-efficacy. Age, symptoms of depression, and memory control beliefs accounted for approximately half of the variance in memory self-efficacy ratings. CONCLUSION: These data indicate that although memory self-efficacy may be age sensitive, we detected no differences in subjective views across the three older groups. Implications for cognitive adaptability and successful aging are considered.


Asunto(s)
Envejecimiento/psicología , Envejecimiento Saludable , Memoria/fisiología , Autoeficacia , Adulto , Anciano , Anciano de 80 o más Años , Cognición , Femenino , Estado de Salud , Humanos , Individualidad , Louisiana , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Factores Socioeconómicos , Adulto Joven
7.
CMAJ ; 190(23): E710-E717, 2018 06 11.
Artículo en Inglés | MEDLINE | ID: mdl-29891475

RESUMEN

BACKGROUND: Understanding the complex interaction of risk factors that increase the likelihood of developing common diseases is challenging. The Canadian Partnership for Tomorrow Project (CPTP) is a prospective cohort study created as a population-health research platform for assessing the effect of genetics, behaviour, family health history and environment (among other factors) on chronic diseases. METHODS: Volunteer participants were recruited from the general Canadian population for a confederation of 5 regional cohorts. Participants were enrolled in the study and core information obtained using 2 approaches: attendance at a study assessment centre for all study measures (questionnaire, venous blood sample and physical measurements) or completion of the core questionnaire (online or paper), with later collection of other study measures where possible. Physical measurements included height, weight, percentage body fat and blood pressure. Participants consented to passive follow-up through linkage with administrative health databases and active follow-up through recontact. All participant data across the 5 regional cohorts were harmonized. RESULTS: A total of 307 017 participants aged 30-74 from 8 provinces were recruited. More than half provided a venous blood sample and/or other biological sample, and 33% completed physical measurements. A total of 709 harmonized variables were created; almost 25% are available for all participants and 60% for at least 220 000 participants. INTERPRETATION: Primary recruitment for the CPTP is complete, and data and biosamples are available to Canadian and international researchers through a data-access process. The CPTP will support research into how modifiable risk factors, genetics and the environment interact to affect the development of cancer and other chronic diseases, ultimately contributing evidence to reduce the global burden of chronic disease.


Asunto(s)
Investigación Biomédica/organización & administración , Enfermedad Crónica/prevención & control , Medicina Preventiva/organización & administración , Adulto , Anciano , Canadá/epidemiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Desarrollo de Programa , Estudios Prospectivos , Factores de Riesgo , Voluntarios
8.
Prev Med ; 105: 326-331, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28987335

RESUMEN

Owing to an aging population and medical advances, the anticipated growth and prevalence of multimorbidity has been recognized as a significant challenge and priority in health care settings. Although physical activity has been shown to play a vital role in the primary and secondary prevention of chronic disease, much less is known about the relationship between physical activity and multimorbidity. The objective of the present study was to examine the relationship between physical activity levels and multimorbidity in male and female adults after adjusting for key demographic, geographical, and lifestyle factors. The study drew data from a prospective cohort in Atlantic Canada (2009-2015). The sample included 18,709 participants between the ages of 35-69. Eighteen chronic diseases were identified. Physical activity levels were estimated based on the long form of the International Physical Activity Questionnaire. Using logistic regression analysis, we found that multimorbid individuals were significantly more likely to be physically inactive (OR=1.26; 95% CI 1.10, 1.44) after adjusting for key sociodemographic and lifestyle characteristics. Additional stratified analyses suggest that the magnitude of the effect between multimorbidity and physical activity was stronger for men (OR=1.41; 95% CI 1.12, 1.79) than women (OR=1.18; CI 1.00, 1.39) and those living in rural (OR=1.43; CI 1.10, 1.85) versus urban (OR=1.20; CI 1.02, 141) areas. Given the generally low levels of physical activity across populations and a growing prevalence of multimorbidity, there is a need for a prospective study to explore causal associations between physical activity, multimorbidity, and health outcomes.


Asunto(s)
Enfermedad Crónica/prevención & control , Ejercicio Físico/fisiología , Estilo de Vida , Multimorbilidad/tendencias , Adulto , Anciano , Canadá , Femenino , Geografía , Conductas Relacionadas con la Salud , Encuestas Epidemiológicas , Humanos , Masculino , Persona de Mediana Edad
9.
Phys Chem Chem Phys ; 19(20): 13010-13021, 2017 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-28480933

RESUMEN

The elucidation of catalyst surface-plasma interactions is a challenging endeavor and therefore requires thorough and rigorous assessment of the reaction dynamics on the catalyst in the plasma environment. The first step in quantifying and defining catalyst-plasma interactions is a detailed kinetic study that can be used to verify appropriate reaction conditions for comparison and to discover any unexpected behavior of plasma-assisted reactions that might prevent direct comparison. In this paper, we provide a kinetic evaluation of CH4 activation in a dielectric barrier discharge plasma in order to quantify plasma-catalyst interactions via kinetic parameters. The dry reforming of CH4 with CO2 was studied as a model reaction using Ni supported on γ-Al2O3 at temperatures of 790-890 K under atmospheric pressure, where the partial pressures of CH4 (or CO2) were varied over a range of ≤25.3 kPa. Reaction performance was monitored by varying gas hourly space velocity, plasma power, bulk gas temperature, and reactant concentration. After correcting for gas-phase plasma reactions, a linear relationship was observed in the log of the measured rate constant with respect to reciprocal power (1/power). Although thermal catalysis displays typical Arrhenius behavior for this reaction, plasma-assisted catalysis occurs from a complex mixture of sources and shows non-Arrhenius behavior. However, an energy barrier was obtained from the relationship between the reaction rate constant and input power to exhibit ≤∼20 kJ mol-1 (compared to ∼70 kJ mol-1 for thermal catalysis). Of additional importance, the energy barriers measured during plasma-assisted catalysis were relatively consistent with respect to variations in total flow rates, types of diluent, or bulk reaction temperature. These experimental results suggest that plasma-generated vibrationally-excited CH4 favorably interacts with Ni sites at elevated temperatures, which helps reduce the energy barrier required to activate CH4 and enhance CH4 reforming rates.

10.
Mem Cognit ; 44(8): 1215-1227, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27400995

RESUMEN

We explored 2 research questions: whether criterion shifts within different recognition tasks are reliable across testing sessions and whether such shifts correlate across the different tasks. In Experiment 1, we established consistent group-level criterion shifting based on expected strength of target items in the test. False-alarm rates were higher when expected strength was weak as opposed to strong, even when expected strength cues were unblocked at test. Test-retest reliabilities in this strength-cuing environment were good. In Experiment 2, we manipulated either the probability (high or low) or expected memory strength (strong or weak) of target items and had people perform both tasks on each of 2 days of testing. Varying the probability of target items consistently produced criterion shifts, as did manipulating target memory strength. Regarding individual differences, shifting in a given test context predicted shifting on a second day in that same test context. However, one's tendency to shift a decision criterion on 1 type of test context did not predict one's tendency to do so in the other. The extent to which people shifted their decision criterion in recognition memory testing was largely dependent on the type of test.


Asunto(s)
Reconocimiento en Psicología/fisiología , Aprendizaje Verbal/fisiología , Adulto , Humanos , Adulto Joven
11.
Mem Cognit ; 44(4): 650-9, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26810799

RESUMEN

In three experiments we explored cross-dimensional cuing effects in a multidimensional source encoding and retrieval paradigm. We employed a bias-controlled experimental method of source cuing at retrieval (Starns & Hicks, 2013) in an attempt to improve retrieval of location information indirectly by cuing gender information. Encoded words were situated on the left or right side of a computer monitor and associated with either a male or a female face. When multiple faces were used across the set of encoded words, reinstating the correct face at retrieval alongside an incorrect, opposite-gender face cue improved male/female source decisions for test words. However, this powerful test cue did not improve memory for the encoded location of the words, suggesting that within-dimension cuing does not produce cross-dimensional cuing. This null outcome was found when gender decisions were required (Experiments 1A and 2) or not required (Experiment 1B) prior to location decisions. Nor was cross-dimension cuing found when subjects were told to expect a source test of both gender and location information at retrieval (Experiment 2). Our findings reinforce prior work demonstrating that multiple context dimensions can be bound to item information without any direct binding between the contexts.


Asunto(s)
Señales (Psicología) , Reconocimiento Facial/fisiología , Recuerdo Mental/fisiología , Memoria Espacial/fisiología , Adulto , Humanos , Factores Sexuales , Adulto Joven
12.
Mem Cognit ; 42(5): 742-54, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24523046

RESUMEN

In seven experiments, we explored the potential for strength-based, within-list criterion shifts in recognition memory. People studied a mix of target words, some presented four times (strong) and others studied once (weak). In Experiments 1, 2, 4A, and 4B, the test was organized into alternating blocks of 10, 20, or 40 trials. Each block contained lures intermixed with strong targets only or weak targets only. In strength-cued conditions, test probes appeared in a unique font color for strong and weak blocks. In the uncued conditions of Experiments 1 and 2, similar strength blocks were tested, but strength was not cued with font color. False alarms to lures were lower in blocks containing strong target words, as compared with lures in blocks containing weak targets, but only when strength was cued with font color. Providing test feedback in Experiment 2 did not alter these results. In Experiments 3A-3C, test items were presented in a random order (i.e., not blocked by strength). Of these three experiments, only one demonstrated a significant shift even though strength cues were provided. Overall, the criterion shift was larger and more reliable as block size increased, and the shift occurred only when strength was cued with font color. These results clarify the factors that affect participants' willingness to change their response criterion within a test list.


Asunto(s)
Señales (Psicología) , Desempeño Psicomotor/fisiología , Reconocimiento en Psicología/fisiología , Adulto , Femenino , Humanos , Masculino , Adulto Joven
13.
Int J Circumpolar Health ; 83(1): 2309756, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38290014

RESUMEN

In very cold environments, it may be burdensome or impossible for the polar medic to prevent medicines from freezing. We sought to investigate whether orientation affected the risk that glass ampoules of 1 in 1000 adrenaline, an important emergency drug, would break during freezing and subsequent thawing. Ampoules of adrenaline were orientated either upright, horizontally or inverted. They were exposed to freezing temperatures (-25°C or -80°C) and then allowed to thaw. A crossover design was used whereby the orientation of unbroken ampoules was changed for the next trial. No ampoules broke when frozen at -25°C and then thawed. When this was repeated at -80°C, ampoules reliably broke unless they were upright with no liquid in the top part of the ampoule. Upright orientation prevents the breakage of glass ampoules of 1 in 1000 adrenaline rapidly frozen at -80°C. The polar medic may consider storing ampoules upright if they are to be exposed to very low temperatures.


Asunto(s)
Epinefrina , Vidrio , Humanos , Temperatura , Congelación
14.
ACS Catal ; 14(9): 6749-6798, 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38721380

RESUMEN

Thermal approaches have played a dominant role in driving chemical reactions within the chemicals and fuels industries, benefiting from ongoing enhancements in efficiency via heat integration, catalyst development, and process intensification. Nevertheless, these traditional thermal approaches remain heavily reliant on fossil fuels, and there exists an urgent demand for the implementation of renewable energy technologies to synthesize fuels, commodity chemicals, and specialty chemicals. Nonthermal plasmas have gained considerable attention in recent years as a promising solution, and the prospects of combining plasmas with suitable catalysts have become even more appealing. Moreover, the evolution of nonthermal plasma catalysis approaches for the generation of clean hydrogen could be transformative in reducing greenhouse gas emissions. This comprehensive review highlights the influential contributions in plasma catalysis for hydrogen production, discusses recent advancements, and provides future prospects for researchers aiming to advance the production of clean hydrogen.

15.
Mem Cognit ; 41(7): 953-66, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23666645

RESUMEN

Reinstating source details at test often has no impact on source memory. We tested the proposition that participants internally reinstate source cues when such cues are not provided by the experimenter, thus making the external cues redundant. Participants studied words paired with either a male or a female face and were later asked to specify the gender of the face studied with each word. To disrupt the ability to internally reinstate sources, some participants saw eight male faces and eight female faces throughout the study list (multiple-face condition), making it difficult to determine which face should be internally reinstated for uncued test trials. Other participants saw only a single face for each gender (single-face condition), which should facilitate internal reinstatement. Across three experiments, participants in the multiple-face condition showed improved source discrimination when the studied faces were reinstated at test, as compared to uncued trials. In contrast, participants in the single-face condition showed no effect of the face cues. Moreover, the cuing effect for the multiple-face condition disappeared when the test structure facilitated internal reinstatement. Overall, the experiments support the contention that internal reinstatement is a natural part of source retrieval that can mask the effects of external cues.


Asunto(s)
Señales (Psicología) , Memoria Episódica , Recuerdo Mental/fisiología , Adulto , Humanos , Distribución Aleatoria , Adulto Joven
16.
ACS Eng Au ; 2(6): 535-546, 2022 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-36573176

RESUMEN

Plasma-surface coupling has emerged as a promising approach to perform chemical transformations under mild conditions that are otherwise difficult or impossible thermally. However, a few examples of inexpensive and accessible in situ/operando techniques exist for observing plasma-solid interactions, which has prevented a thorough understanding of underlying surface mechanisms. Here, we provide a simple and adaptable design for a dielectric barrier discharge (DBD) plasma cell capable of interfacing with Fourier transform infrared spectroscopy (FTIR), optical emission spectroscopy (OES), and mass spectrometry (MS) to simultaneously characterize the surface, the plasma phase, and the gas phase, respectively. The system was demonstrated using two example applications: (1) plasma oxidation of primary amine functionalized SBA-15 and (2) catalytic low temperature nitrogen oxidation. The results from application (1) provided direct evidence of a 1% O2/He plasma interacting with the aminosilica surface by selective oxidation of the amino groups to nitro groups without altering the alkyl tether. Application (2) was used to detect the evolution of NOX species bound to both platinum and silica surfaces under plasma stimulation. Together, the experimental results showcase the breadth of possible applications for this device and confirm its potential as an essential tool for conducting research on plasma-surface coupling.

17.
Mem Cognit ; 39(5): 818-26, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21286898

RESUMEN

In this study, we examined a source-monitoring phenomenon that arises from reactivated related information from the study phase. Three experiments showed that source attributions for target events were influenced not only by the target item itself, but also by studied information about related items. In Experiment 1, source memory for target items that have a high forward association value to a single related study item (e.g., credit) were affected by the source of the associated information (e.g., card), so that memory performance was better when associated items were presented in the same source rather than a different source. A similar effect occurred with bidirectional associates (Exp. 2), as well as with synonymous pairs of words (Exp. 3). We argue that the source information of the reactivated material can be commingled with information about a candidate during a source judgment at retrieval and thereby can affect performance.


Asunto(s)
Aprendizaje por Asociación , Atención , Recuerdo Mental , Aprendizaje por Asociación de Pares , Lectura , Semántica , Percepción del Habla , Humanos , Imaginación , Reconocimiento en Psicología , Represión Psicológica
18.
Exp Aging Res ; 37(3): 293-309, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21534030

RESUMEN

Eight participants with probable Alzheimer's disease (AD) were trained to recall names of countries using the spaced-retrieval memory intervention. Six training sessions were administered on alternate days over a 2-week period. Half of the participants studied a target country alone and the other half studied a target country along with eight distractor countries. Training stimuli appeared in text-only format in half of the sessions and text with a color photograph of the country in the other sessions. On each trial, participants selected the target at increasingly longer retention intervals, contingent upon successful recall. Results indicated that the mean proportion of correct trials and longest duration achieved increased across training sessions, confirming the success of the spaced-retrieval intervention. Pictorial illustrations enhanced explicit memory for target country names. Implications of these data for current views on memory remediation in cognitively impaired older adults are discussed.


Asunto(s)
Enfermedad de Alzheimer/psicología , Atención , Recuerdo Mental , Aprendizaje Verbal , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Asociación , Femenino , Humanos , Masculino , Memoria a Corto Plazo , Escala del Estado Mental/estadística & datos numéricos , Psicometría , Retención en Psicología
19.
Chem Commun (Camb) ; 57(100): 13772-13775, 2021 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-34860217

RESUMEN

Oligomerization of light olefins has become an essential step to convert gaseous olefins to liquid fuels and value-added chemicals. Here, we report the synthesis and application of nickel single sites isolated on Wells Dawson polyoxometalate defects as stable and regenerable catalysts for ethylene oligomerization.

20.
Appl Radiat Isot ; 167: 109491, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33121893

RESUMEN

Arsenic is a toxic metalloid which has been associated with a wide range of health effects in humans including skin abnormalities and an elevated risk of skin, bladder, kidney, and lung cancer, diabetes, and cardiovascular disease. The measurement of arsenic concentration in nail clippings is often used in population studies as an indicator of arsenic exposure. Portable X-ray fluorescence (XRF) is an emerging technique for measuring arsenic in nail clippings. In the current study, single toenail clippings from 60 Atlantic Canadian participants were assessed for arsenic using a new portable XRF approach. A mono-energetic portable XRF system using doubly curved crystal optics was used to measure each clipping for a total of 900 s. Energy spectra from each clipping were analyzed for arsenic characteristic X-rays to provide a normalized arsenic signal. The same clippings were then analyzed for arsenic concentration using a "gold standard" method of inductively coupled plasma mass spectrometry (ICP-MS). Nail clipping arsenic concentrations measured by ICP-MS ranged from 0.030 µg/g to 2.57 µg/g, with a median result of 0.14 µg/g. Portable XRF results for arsenic were compared against ICP-MS arsenic concentrations, with a linear equation of best fit determined between the two variables. A correlation coefficient of r = 0.77 was found from the 59 nail clippings returning an ICP-MS arsenic concentration above the limit of quantitation. When the comparison was limited to the 20 clippings having an XRF normalized signal at least twice as large as the associated uncertainty of measurement, the correlation coefficient was r = 0.89. With the selection of an arsenic concentration of 0.1 µg/g as a cut-off value between "exposed" and "non-exposed" individuals, the XRF method provided a test sensitivity of 76% and a specificity of 81%. The corresponding positive predictive value was 88% and the negative predictive value was 65%. The portable XRF technique used in this study shows promise as a means of assessing arsenic concentration in toenail clippings.


Asunto(s)
Arsénico/análisis , Uñas/química , Espectrometría por Rayos X/métodos , Calibración , Humanos
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