RESUMO
Associative memory involves the ability to encode and remember the relationship between individual items. This ability can become diminished when there is a high degree of similarity between stimuli that are being learned. Associative memory errors often stem from the fact that lures include a high degree of item familiarity as well as mnemonic similarity with the original associative episode. The current set of experiments examined how this overlap, in the form of within-category similarity, affects veridical and false retrieval in both younger and older adults. Across three experiments, results suggest that mnemonic overlap between targets and lures is detrimental to the ability to discriminate between highly similar information. Specifically, shared category membership for targets and lures led to increased false associative memories across age groups. These results have implications for scenarios where there is a high degree of overlap between target and lure events and indicate that these types of associative memory distinctions are difficult irrespective of age.
Assuntos
Memória , Reconhecimento Psicológico , Humanos , Idoso , Rememoração Mental , Cognição , EnvelhecimentoRESUMO
Approximately 12% of apparently previously cognitively well patients undergoing anaesthesia and noncardiac surgery will develop symptoms of cognitive dysfunction after their procedure. Recent articles in this Journal have highlighted the difficulties of confirming any clear links between anaesthesia and cognitive dysfunction, in part because of the lack of consistency regarding definition and diagnosis. Postoperative cognitive dysfunction (POCD) is usually self-limiting and rarely persists in the longer term, although plausible biological mechanisms for an impact on brain protein deposition do exist. Clinical research studies are frequently confounded by a lack of agreed definitions and consistency of testing. Preoperative assessment of neurocognitive function and risk factor identification is imperative in order to ascertain the true extent of POCD and any causative link to anaesthesia and surgery. At present a multidisciplinary care bundle approach to risk factor stratification and reduction is the most attractive management plan based on evidence of slight benefit from individual interventions. As yet no individual anaesthetic technique, drug or mode of monitoring has been proved to reduce the incidence of POCD. Providing patients with appropriate and accurate information can be difficult because of conflicting evidence. The Royal College of Anaesthetists' patient liaison group has produced a useful patient information leaflet that is designed to provide guidance in discussions of individual risks whilst considerable uncertainties remain.
Assuntos
Anestesia/efeitos adversos , Anestésicos/efeitos adversos , Disfunção Cognitiva/induzido quimicamente , Delírio/induzido quimicamente , Demência/complicações , Complicações Pós-Operatórias/induzido quimicamente , Demência/diagnóstico , Humanos , Testes Neuropsicológicos , Fatores de RiscoRESUMO
The presence of Aedes albopictus (Skuse) in the Torres Strait of northern Australia increases the potential for colonization and establishment on the mainland. However, there is a possibility that native species that occupy the same habitats may influence the population performance of Ae. albopictus, potentially affecting the establishment of this species in Australia. Cohabitation experiments were performed with the endemic Aedes notoscriptus (Skuse), which has been found occupying the same larval habitats as Ae. albopictus in the Torres Strait and is the most widespread container-inhabiting Aedes species in Australia. The influence of environmental factors and cohabitation between the two species was examined using different climates, food resource levels, food resource types, and species densities. Survivorship proportions and a population performance index (λ') were calculated and compared. The consequences of increased Ae. notoscriptus densities were reduced survivorship and λ' for Ae. albopictus. Despite this, the mean λ' of Ae. albopictus and Ae. notoscriptus was consistently ≥ 1.06, indicating both species could increase under all conditions, potentially due to increasing conspecific densities negatively affecting Ae. notoscriptus. The outcomes from this study suggest that the preexisting presence of Ae. notoscriptus may not prevent the establishment of Ae. albopictus in Australia.
Assuntos
Aedes/fisiologia , Distribuição Animal , Clima , Meio Ambiente , Animais , Comportamento Competitivo , Feminino , Masculino , Densidade Demográfica , QueenslandRESUMO
Kunzea ambigua (Smith) Druce (Myrtaceae) is an Australian native plant, commonly known as tick bush. The essential oil of the plant has been proposed as a potential mosquito repellent. Commercial K. ambigua oil was analyzed by gas chromatography-mass spectrometry (GC-MS) and its composition compared with that of oils from two individual K. ambigua plants and citronella oil. K. ambigua oils were studied for their repellency against Aedes aegypti L. Formulations of three different K. ambigua essential oils (30% vol:vol) were tested for repellency to mosquitoes using human volunteers. One oil was compared with citronella and N,N'-diethyl-3-methylbenzamide (deet) for repellency. Oil formulations were also tested for repellency with and without the addition of 5% vanillin. The formulation containing commercially produced K. ambigua oil had a mean complete protection time (CPT) of 49 +/- 24 (SD) min. All the K. ambigua formulations had comparable repellency to 40% citronella. However, the 60% citronella formulation showed higher repellency than the 40% K. ambigua formulation. The addition of 5% vanillin did not increase the repellency of K. ambigua oil. Both K. ambigua oil and citronella were significantly less repellent than deet. The K. ambigua essential oil formulations should not be advocated for use as repellents in regions prone to mosquito-borne disease.
Assuntos
Aedes/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Kunzea/química , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Animais , Austrália , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Repelentes de Insetos/química , Repelentes de Insetos/isolamento & purificação , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Compostos Orgânicos Voláteis/isolamento & purificaçãoRESUMO
The complete mitochondrial genomes for two deeply divergent lineages of the urban adapted mosquito Aedes notoscriptus Skuse (Diptera: Culicidae) in Australia were sequenced using a combination of next generation Illumina and traditional Sanger sequencing. The 15,846 and 15,851 bp circular genomes share 95.0% nucleotide identity. They both have the full complement of 37 metazoan genes and identical gene arrangements to previously published Culicidae species with the one non-coding A + T rich control region present between rns and tRNA-Ile. All protein initiation codons are ATN apart from COX1 (TCG). Eight protein coding genes encode full TAA stop codons, one uses an incomplete TA and four use T. Typical cloverleaf structures containing DHU and TΨC stem and loops can be inferred for all 22 tRNAs.
Assuntos
Aedes/genética , DNA Mitocondrial/genética , Genoma Mitocondrial , Filogenia , Animais , Sequência de Bases , Genes Mitocondriais , Variação GenéticaRESUMO
Data from 722 urine collections (627 patients) from 14 medical facilities were used to compare measured creatinine clearance values with clearance estimates calculated using three "urine-free' mathematical formulas. The influence of two patient weight variables (actual weight, lean body weight) and the level of renal function on clearance prediction was assessed. In addition, site parameters (region, facility), time parameters (month, day, day of the week), and patient parameters (age, sex, height, weight, diagnoses) were evaluated for their statistical influence on the relationship between measured clearance and estimates calculated with one of the methods. Strong, statistically significant correlations were observed between clearance values estimated with each prediction method and measured clearances. Although statistical differences were noticed between mean values predicted with each method, these differences were clinically insignificant. Use of lean body weight for calculation of creatinine excretion produced clearance estimates that were significantly lower than those obtained with actual weight and substantially closer to measured clearance values. Among patient variables, age and two specific diagnoses (congestive heart failure and pregnancy), were statistically associated with variability in the relationship between measured and predicted clearance. Interregional and interfacility differences in the measured-predicted clearance relationship, variability associated with the day of the week of collection, and tendency of the urine-free formulas to over-predict clearance support potential inaccuracy of measured clearance determination. The results suggest that inaccuracies in clearance determination, rather than inadequacies of urine-free prediction methods, account for the majority of the observed variability in the relationship.
Assuntos
Creatinina/urina , Testes de Função Renal/métodos , Fatores Etários , Peso Corporal , Estudos de Avaliação como Assunto , Humanos , Fatores SexuaisRESUMO
The drug, alpha-bungarotoxin (BTX) is believed to be a 'pure' nicotinic antagonist. Hence, use of this drug should avoid the secondary actions associated with other nicotinic antagonists. The hypothesis that the motor nerve terminal responds to the presence of acetylcholine (ACh) by releasing less transmitter was tested by examining the effects of BTX on end-plate potentials (EPPs), miniature end-plate potentials (MEPPs), and quantal release at the rat diaphragm neuromuscular junction. Analysis of EPP and MEPP amplitudes and quantal release demonstrate that BTX significantly increases transmitter release at the onset of tetanic stimulation (50 Hz). Like other nicotinic antagonists, BTX was not able to sustain enhanced quantal release during a brief train of 40 stimuli and resulted in greater decline in EPP amplitude during tetanic stimulation. The data suggests that negative feedback regulation by presynaptic autoreceptors only serves a functional role at the onset of stimulation and that other factors such as transmitter supply or adenosine regulation may serve to dominate transmitter release during maintained tetanic stimulation.
Assuntos
Bungarotoxinas/farmacologia , Junção Neuromuscular/metabolismo , Neurotransmissores/metabolismo , Antagonistas Nicotínicos/farmacologia , Potenciais de Ação/efeitos dos fármacos , Animais , Diafragma/efeitos dos fármacos , Diafragma/inervação , Diafragma/metabolismo , Estimulação Elétrica , Feminino , Técnicas In Vitro , Placa Motora/efeitos dos fármacos , Terminações Nervosas/efeitos dos fármacos , Terminações Nervosas/metabolismo , Junção Neuromuscular/efeitos dos fármacos , Nervo Frênico/efeitos dos fármacos , Nervo Frênico/metabolismo , Ratos , Receptores Nicotínicos/efeitos dos fármacosRESUMO
The mosquitoes associated with 2 saline wetlands at Homebush Bay, Sydney, Australia, were investigated over 5 consecutive seasons. Twenty-one species were collected in adult traps at the 2 sites but the saline wetlands supported larvae of only 4 species: Aedes alternans, Aedes camptorhynchus, Aedes vigilax, and Culex sitiens. Of these, Ae. vigilax and Cx. sitiens were the most common, and their peak abundances generally occurred during February and April, respectively. Both wetlands were influenced by tides and rainfall-runoff, and a lack of regular tidal exchange in the mangroves and inadequate drainage of the saltmarsh provided potential habitat. Populations of Ae. vigilax and Cx. sitiens at the Newington site were greater than those at the Bicentennial Park site, because of more extensive habitat at the former, but were diminished by irregular ground-based applications of temephos during the middle 3 years of the study. Populations at the Bicentennial Park site, not subjected to the larvicide, were typically smaller but more consistently related to influences of tide and rainfall through the 5 seasons. During the final season, populations of both species in both wetlands were enhanced by exceptional tide penetration and rainfall. Helicopter applications of Bacillus thuringiensis israelensis larvicide were employed at both sites and effectively suppressed populations of both pest species. For future management, provision of full tidal exchange and water recirculation to reduce the area of water impounded within the mangroves and retained in depressions on the marshes should significantly suppress the pest populations and relieve reliance on control agents.
Assuntos
Controle de Mosquitos , Aedes/classificação , Animais , Austrália , Culex/classificação , Poaceae , Densidade Demográfica , Estações do Ano , Água do MarAssuntos
Prescrições de Medicamentos , Reforma dos Serviços de Saúde/organização & administração , Equipe de Assistência ao Paciente/organização & administração , Farmacêuticos/organização & administração , Autonomia Profissional , Análise Custo-Benefício , Necessidades e Demandas de Serviços de Saúde , Humanos , Inovação Organizacional , Avaliação de Resultados em Cuidados de Saúde , Estados UnidosRESUMO
In Queensland, Australia, in response to isolated cases of dengue infection, larval control of the vector Aedes aegypti (L.) (Diptera: Culicidae) is targeted at breeding sites within 200 m of a case and interior spraying with a pyrethroid adulticide is targeted at premises within 100 m. To ascertain whether these limits are appropriate, we conducted a mark-release-recapture study to measure the dispersal of female Ae. aegypti in the city of Cairns where transmission occurs. Female mosquitoes reared from wild collected eggs were differentially marked with fluorescent dust depending on whether they were to be released blood-fed or non-blood-fed, and a total of 1,948 females was released. A total of 132 sticky ovitraps was set at 64 premises within a 200 m radius and collections of trapped adults were made at 5-15 days post-release. Sixty-seven females (3.4%) were recaptured, with the furthest being caught 200 m from the release point, and the mean distance travelled was 78 m. Overall, 23.1% of the recaptures outside the release site were taken beyond 100 m by day 15. Dispersal was comparable for both blood-fed and non-blood-fed releases. There was a significant tendency for dispersal to be in a north-westerly direction, probably because of the presence of numerous containers and heavy shading by trees in this direction and a busy road to the south of the release point that appeared to inhibit dispersal. The results suggest that adulticiding may have to be extended beyond 100 m if more than 8 days have elapsed since female Ae. aegypti could have fed upon a viraemic dengue case. The study also shows that dispersal is not random, and that it may be possible to maximize vector control by taking into account environmental factors that affect the direction of female mosquito flight.
Assuntos
Aedes/fisiologia , Demografia , Insetos Vetores/fisiologia , Movimento , Animais , Feminino , Corantes Fluorescentes , Densidade Demográfica , Dinâmica Populacional , Queensland , Manejo de Espécimes/métodosRESUMO
We have recently proposed a scheme to produce coherent radiation at eight or more wavelengths between 158 and 242 nm by optically pumping a high-lying electronic level of nitric oxide. We report here the successful operation of this scheme to produce laser oscillation at 218 nm. The possibility of using this scheme to produce laser oscillation at other wavelengths is discussed.
RESUMO
We report recent experiments that demonstrate the line tunability of a fluorine laser-pumped nitric oxide laser. Laser oscillation has been observed at 589, 234, 226, 218, 211, and 163 nm. The possibility of achieving laser oscillation on further UV and vacuum UV laser transitions in nitric oxide is discussed.
RESUMO
Frequency up-conversion of XeCl-laser radiation (308 nm) and KrF-laser radiation (249 nm) by two-photon resonantly enhanced four-wave mixing in Mg vapor is reported. A dye laser tuned to two-photon resonance with the 3s-3d(1)D(2) Mg level was used. The dependences of generated signals at 127 and 115 nm on input intensity and number density were investigated. No saturation was observed up to 4 x 10(9) W/cm(2) (249 nm) and 6 x 10(8) W/cm(2) (308 nm). The 115-nm signal was phase matched by using Xe. Conversion efficiencies and signal linewidths are discussed.
RESUMO
We report, for what we believe to be the first time, a Ce:LiCAF laser pumped by ultraviolet radiation obtained by sum-frequency mixing of the green and the yellow output from a copper-vapor laser. The 7-kHz pulse repetition frequency free-lasing Ce:LiCAF laser yielded a maximum output power of 530 mW, with a slope efficiency of 32%, from a pump power of 1.9 W. With a single prism tunability from 280.5 to 316 nm was achieved.
RESUMO
High-average-power broadband 780-nm slab Ti:sapphire lasers, pumped by a kilohertz pulse repetition frequency copper vapor laser (CVL), were demonstrated. These lasers are designed for damage-free power scaling when pumped by CVL's configured for maximum output power (of order 100 W) but with poor beam quality (M(2) approximately 300). A simple Brewster-angled slab laser side pumped by a CVL produced 10-W average power (1.25-mJ pulses at 8 kHz) with 4.2-ns FWHM pulse duration at an absolute efficiency of 15% (68-W pump power). Thermal lensing in the Brewster slab laser resulted in multitransverse mode output, and pump absorption was limited to 72% by the maximum doping level for commercially available Ti:sapphire (0.25%). A slab laser with a multiply folded zigzag path was therefore designed and implemented that produced high-beam-quality (TEM(00)-mode) output when operated with cryogenic cooling and provided a longer absorption path for the pump. Excessive scattering of the Ti:sapphire beam at the crystal surfaces limited the efficiency of operation for the zigzag laser, but fluorescence diagnostic techniques, gain measurement, and modeling suggest that efficient power extraction (>15 W TEM(00), >23% efficiency) from this laser would be possible for crystals with an optical quality surface polish.
RESUMO
Warfarin maintenance-dose requirements predicted by six mathematical methods based on initial response to therapy were compared with patients' actual dose requirements in a multicenter trial. Data were collected for patients who had received an initial regimen of warfarin sodium 10 mg orally every 24 hours for three days and for whom a prothrombin time (PT) had been determined 16-20 hours after the third dose. Patients' individual dose requirements and PT values were recorded during one to three follow-up visits after discharge from one of seven medical centers. Prothrombin ratios (patient PT divided by control PT) calculated on day 4 were used for maintenance-dose prediction by five methods; a sixth method was based on the cumulative warfarin dose-PT response curve up to a PT value of 20 seconds. For 54 men and 30 women who qualified for the study, 197 maintenance-dose-PT response measurements were recorded; 95 in the first four weeks of therapy, 76 during weeks 5-12, and 26 at 6-12 months after initial treatment. Prothrombin ratios were within the therapeutic range (PT 1.5-2.5 times the control value) in 154 observations, and the mean actual warfarin sodium maintenance dose associated with therapeutic response was 7.6 mg/day. For patients with therapeutic prothrombin ratios, dose predictions by the five methods using prothrombin ratios (PRs) correlated significantly with actual dose requirements. The formula that predicted doses numerically closest to the actual dose is as follows: Dose = 11.17 - 21.08 (log PR). Only 45 observations were obtained for the sixth prediction method, and the correlation between actual and predicted doses was not significant. Initial warfarin maintenance-dose requirements can be predicted effectively based on one PT determination after administration of three daily 10-mg doses.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Varfarina/administração & dosagem , Adulto , Idoso , Ensaios Clínicos como Assunto , Custos e Análise de Custo , Estudos de Avaliação como Assunto , Feminino , Seguimentos , Humanos , Tempo de Internação , Masculino , Métodos , Pessoa de Meia-Idade , Prognóstico , Embolia Pulmonar/tratamento farmacológico , Trombose/tratamento farmacológicoRESUMO
Patient data were analyzed retrospectively to evaluate the relationship between several body-weight variables and creatinine production and clearance. Data from 722 creatinine clearance determinations in 627 patients older than 12 years were analyzed. Weight variables were actual body weight (ABW), lean body weight (LBW), ideal body weight (IBW), and lean body mass (LBM). Weight-independent and weight-dependent clearance prediction methods were evaluated. Actual creatinine clearance values were compared with these predictions. Use of LBW and IBW produced equivalent estimates of creatinine clearance that were closer to measured values than those obtained with ABW. The use of LBW or IBW was not appropriate in patients less than 60 inches tall nor in morbidly obese patients. Weight-dependent clearance estimation was superior to weight-independent predictions in morbidly obese patients. A new LBM-based clearance estimation formula was derived; it may be useful for patients less than 60 inches tall. The use of LBM, particularly in patients less than 60 inches tall, should be investigated further.