Temporal Changes In Sensitivity Research Articles

Bayesian evaluation of temporal changes in sensitivity and specificity of three serological tests for multiple circulating strains of rabbit haemorrhagic disease virus

Competition and indirect ELISAs are currently being used to monitor rabbit haemorrhagic disease viruses (RHDV1 and RHDV2) in rabbits worldwide. Temporal changes in the sensitivity (Se) and specificity (Sp) of RHDV1 competition-ELISA (cELISA1), RHDV2 competition-ELISA (cELISA2), and RHDV1 Immunoglobulin G (IgG1) ELISA, were investigated using Bayesian Latent Class models (BCLM) in the Australian wild rabbit population where both viruses circulate simultaneously and a long-term serological dataset exists. When cELISA1 was compared to IgG1 ELISA, the Se of cELISA1 improved while the Sp of IgG1 ELISA declined over the 2011–21. This corresponded with a decline in the true RHDV1 prevalence in 2018–21, suggesting that a large proportion of RHDV1 exposed rabbits survived the introduction and dominance of RHDV2 up to approximately 2017/2018, after which they died and were not replaced. The Se and Sp estimates for 2014–15 for both cELISA1 and IgG1 ELISA, and the true prevalence when analysing all three tests together were similar to those obtained from the analysis of cELISA1/IgG1 ELISA. The same was also true for the Se and Sp of cELISA2 and IgG1 ELISA estimates from 2018 onwards. This suggests that RHDV1 was the dominant infection type in 2014–15, but RHDV2 was the dominant infection type in 2018–21. Further, the increase in Se of cELISA2 and the low Sp of IgG1 ELISA in the cELISA2/IgG1 ELISA analysis, compared to the Se of cELISA2 and Sp of IgG1 ELISA when analysing all three tests together suggests that the underlying infection status was more influenced by RHDV2 and that the higher Se of IgG1 ELISA is due to cross-reaction of RHDV2 antibodies on IgG1 ELISA. The true prevalence data suggest that RHDV2 exposure peaked in 2017. Our findings show that test characteristics changed in response to the changing virus prevalences over time. IgG1 ELISA, currently having a high Se, should be used to monitor both viruses and will perform better than both cELISAs.

Base rates bias performance in a temporal bisection task.

We investigated how base rates affect temporal discrimination. In a temporal bisection task, pigeons learned to choose one key after a short sample and another key after a long sample. When presented with a range of intermediate samples they produced a psychometric function characterized by a bias and a scale parameter. When one of the trained samples was more frequent than the other, only the location parameter changed, with the pigeons biasing their choices toward the key associated with the most frequent sample. We then reproduced the bisection task in a long operant chamber, with choice keys far apart, and tracked the pigeons' motion patterns during the sample. Pigeons learned to approach the short key following sample onset, wait on the "short side" for a few seconds, and then, when the sample continued, depart toward the long key. This time-place curve was affected by sample base rate: The probability of pigeons going directly to the long side after sample onset increased when long samples were more frequent than short samples, indicating a decrease of temporal control. We found no evidence of changes in temporal sensitivity. The results are most consistent with models of timing that take into account biasing effects and competition for stimulus control. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Temporal Changes in Sensitivity of Zymoseptoria tritici Field Populations to Different Fungicidal Modes of Action

Septoria tritici blotch (STB; Zymoseptoria tritici), one of the most important foliar diseases in wheat, is mainly controlled by the intensive use of fungicides during crop growth. Unfortunately, Z. tritici field populations have developed various extents of resistance to different groups of fungicides. Due to the complete resistance to quinone outside inhibitors (QoIs), fungicidal control of STB relies mainly on demethylation inhibitors (DMIs) and succinate dehydrogenase inhibitors (SDHIs) as well as multi-site inhibitors. In this study, temporal changes in the sensitivity of Z. tritici to selected DMIs (tebuconazole, propiconazole, prothioconazole, prochloraz), SDHIs (boscalid, bixafen), and multi-site inhibitors (chlorothalonil, folpet) were determined in microtiter assays using Z. tritici field populations isolated in 1999, 2009, 2014, and 2020 in a high-disease-pressure and high-fungicide-input area in Northern Germany. For the four tested DMI fungicides, a significant shift towards decreasing sensitivity of Z. tritici field populations was observed between 1999 and 2009, whereby concentrations inhibiting fungal growth by 50% (EC50) increased differentially between the four DMIs. Since 2009, EC50 values of tebuconazole, propiconazole, and prochloraz remain stable, whereas for prothioconazole a slightly increased sensitivity shift was found. A shift in sensitivity of Z. tritici was also determined for both tested SDHI fungicides. In contrast to DMIs, EC50 values of boscalid and bixafen increased continuously between 1999 and 2020, but the increasing EC50 values were much smaller compared to those of the four tested DMIs. No changes in sensitivity of Z. tritici were observed for the multi-site inhibitors chlorothalonil and folpet over the last 21 years. The sensitivity adaptation of Z. tritici to both groups of single-site inhibitors (DMIs, SDHIs) mainly used for STB control represents a major challenge for future wheat cultivation.

Detecting temporal changes in the temperature sensitivity of spring phenology with global warming: Application of machine learning in phenological model

Phenological models can effectively infer historically missing phenological data, so as to investigate the long-term relationship between plants and climate change. Large numbers of ecophysiological and statistical models have been developed in the past few decades, but these models have been unable to make accurate predictions based on external data. Machine learning (ML) methods have an advantage over traditional statistical methods for natural science studies. However, only a few phenological models have been coupled with ML methods. In this study, using long-term leaf unfolding date (LUD) observations collected in Harbin, China, we adopted three popular ML algorithms for predicting plant LUD and compared the performances of 10 phenological models. We detected the temperature sensitivity (ST) of the LUD at the species level for the periods 1962–1987 and 1988–2016 (before and after the recent, sudden warming) and temporal changes in ST with a 15-year moving window for each period. The results show that the gradient boosting decision tree (GBDT) model performs obviously better than the other models for external validation data, while avoiding model overfitting. Most species showed an increase in ST during the 1988–2016 period, and the temporal changes in ST significantly decreased during both periods. The temporal changes in ST from the phenological data predicted by the GBDT model is significantly higher than that of other models, which indicates that the traditional phenological models may underestimate the response of LUD to climate warming. We found a prevalent decline in the magnitude of ST with increasing preseason temperature variance at the species level. Our research suggests that machine learning algorithms should be more widely used in future phenological model research, and temporal changes in ST should be investigated in order to broaden our understanding of plants’ ability to adapt to future climate change.

Biasing performance through differential payoff in a temporal bisection task.

We investigated how differential payoffs affect temporal discrimination. In a temporal bisection task, pigeons learned to choose one key after a short sample and another key after a long sample. When presented with a range of intermediate samples they produced a Gaussian psychometric function characterized by a location (bias) parameter and a scale (sensitivity) parameter. When one key yielded more reinforcers than the other, the location parameter changed, with the pigeons biasing their choices toward the richer key. We then reproduced the bisection task in a long operant chamber, with choice keys far apart, and tracked the pigeons' motion patterns during the sample. These patterns were highly stereotypical-on the long sample trials, the pigeons approached the short key at sample onset, stayed there for a while, and then departed to the long key. The distribution of departure times also was biased when the payoff probabilities differed. Moreover, it is likely that temporal control decreased while control by location increased. No evidence was found of changes in temporal sensitivity. The results are consistent with models of timing that take into account bias effects and competition of stimulus control. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Trends and Variability in Temperature Sensitivity of Lilac Flowering Phenology

AbstractThe responses of plant phenology to temperature variability have many consequences for ecological processes, agriculture, forestry, and human health. Temperature sensitivity (ST) of phenology could measure how and to what degree plant could phenologically track climate change. The long‐term trends and spatial patterns in ST have been well studied for vegetative phenology such as leaf unfolding, but trends to be expected for reproductive phenology in the future remain unknown. Here we investigate trends and factors driving the temporal variation of ST of first bloom date (FBD). Using the long‐term FBD records during 1963–2013 for common lilac (Syringa vulgaris) from 613 stations in Europe, we compared changes in ST from the beginning to the end of the study period. The Spearman partial correlations were used to assess the importance of four influencing factors. The results showed that the temporal changes in ST of FBD varied considerably among time scales. Mean ST decreased significantly by 0.92 days °C−1 from 1963–1972 to 2004–2013 (P < 0.01), but remained stable from 1963–1987 to 1989–2013. The strength of FBD and temperature relationship, the spring temperature variance, and winter chill all impact ST in an expected way at most stations. No consistent responses of ST on photoperiod were found. Our results imply that the trends and variability in ST of flowering phenology are driving by multiple factors and impacted by time scales. Continued efforts are still needed to further examine the flowering‐temperature relationship for other plant species in other climates and environments using similar methods to our study.

Identifying Vasopressor and Inotrope Use for Health Services Research.

Identifying vasopressor and inotrope (vasopressor) use from administrative claims data may provide an important resource to study the epidemiology of shock. Determine accuracy of identifying vasopressor use using International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) coding. Using administrative data enriched with pharmacy billing files (Premier, Inc., Charlotte, NC), we identified two cohorts: adult patients admitted with a diagnosis of sepsis from 2010 to 2013 or pulmonary embolism (PE) from 2008 to 2011. Vasopressor administration was obtained using pharmacy billing files (dopamine, dobutamine, epinephrine, milrinone, norepinephrine, phenylephrine, vasopressin) and compared with ICD-9-CM procedure code for vasopressor administration (00.17). We estimated performance characteristics of the ICD-9-CM code and compared patients' characteristics and mortality rates according to vasopressor identification method. Using either pharmacy data or the ICD-9-CM procedure code, 29% of 541,144 patients in the sepsis cohort and 5% of 81,588 patients in the PE cohort were identified as receiving a vasopressor. In the sepsis cohort, the ICD-9-CM procedure code had low sensitivity (9.4%; 95% confidence interval, 9.2-9.5), which increased over time. Results were similar in the PE cohort (sensitivity, 5.8%; 95% confidence interval, 5.1-6.6). The ICD-9-CM code exhibited high specificity in the sepsis (99.8%) and PE (100%) cohorts. However, patients identified as receiving vasopressors by ICD-9-CM code had significantly higher unadjusted in-hospital mortality, had more acute organ failures, and were more likely hospitalized in the Northeast and West. The ICD-9-CM procedure code for vasopressor administration has low sensitivity and selects for higher severity of illness in studies of shock. Temporal changes in sensitivity would likely make longitudinal shock surveillance using ICD-9-CM inaccurate.

Temporal sensitivity changes with extended training in a bisection task in a transgenic rat model

The present study investigated temporal perception in a Huntington disease transgenic rat model using a temporal bisection procedure. After initial discrimination training in which animals learned to press one lever after a 2-s tone duration, and the other lever after a 8-s tone duration for food reward, the bisection procedure was implemented in which intermediate durations with no available reinforcement were interspersed with trials with the anchor durations. Bisection tests were repeated in a longitudinal design from 4 to 8 months of age. The results showed that response latencies evolved from a monotonic step-function to an inverted U-shaped function with repeated testing, a precursor of non-responding on trials with intermediate durations. We inferred that temporal sensitivity and incentive motivation combined to control the transformation of the bisection task from a two-choice task at the outset of testing to a three-choice task with repeated testing. Changes in the structure of the task and/or continued training were accompanied by improvement in temporal sensitivity. In sum, the present data highlight the possible joint roles of temporal and non-temporal factors in the temporal bisection task, and suggested that non-temporal factors may compensate for deficits in temporal processing.

Why Does the Frequency of Nest Parasitism by the Cuckoo Differ Considerably Between Two Populations of Warblers Living in the Same Habitat?

AbstractThe rate of nest parasitism is a product of two interacting phenomena: host selection by cuckoos and defence by hosts. In our study area the rate of nest parasitism by cuckoos is significantly lower in the great reed warbler (GRW; Acrocephalus arundinaceus) than in the reed warbler (RW; A. scirpaceus), even though they breed in the same habitat and their reproductive biology is similar. We hypothesized that the difference in the proportion of parasitized nests may reflect a narrow selection of host by cuckoos (they prefer RW nests) or/and the relatively better alien egg discrimination in the GRW. In the egg discrimination experiment the GRW rejected the higher proportion of alien eggs than the RW. However, in both species the discriminative ability considerably varied in time, both within the day and within the breeding cycle. A logistic regression model suggests that the GRW would be a frequent host if only nest parasites could exploit the period of its lowest sensitivity to alien eggs. We conclude that the relatively low rate of nest parasitism in the GRW may reflect both its good discriminative ability and the low number of cuckoos that are specialized in dumping eggs to nests of this warbler. The adaptation of cuckoos to the particular host species may involve not only production of mimetic eggs, but also adjusting activity to temporal changes in sensitivity to alien eggs in the host.

Underwater hearing thresholds in pinnipeds measured over a 6-year period

While absolute hearing thresholds have been obtained for some marine mammals, few published data are available on how measurements of individual auditory sensitivity may change over relatively long periods of time. Studies that have investigated temporal changes in sensitivity have typically focused on animals in which differences in hearing are anticipated (age-related hearing loss). This study investigated the replicability of underwater hearing thresholds in prime-aged individuals of three pinniped species over a 6-year period. Aside from their age and experience with behavioral signal detection tasks, test subjects were of similar physical condition throughout this experiment. They were tested in the same enclosure at similar test frequencies (0.1–6.4 kHz) using identical methodology and criteria. Underwater hearing thresholds obtained throughout this testing period were not significantly different. These data indicate that underwater hearing sensitivity may remain relatively stable over long periods in nonsenescent marine mammals, including those regularly exposed to noise. Further, our results suggest that variability in testing equipment and experimental personnel may have little impact on behavioral hearing data, as long as similar testing methodologies and subject response bias are carefully maintained.

Age effects on discrimination of timing in auditory sequences.

The experiments examined age-related changes in temporal sensitivity to increments in the interonset intervals (IOI) of components in tonal sequences. Discrimination was examined using reference sequences consisting of five 50-ms tones separated by silent intervals; tone frequencies were either fixed at 4 kHz or varied within a 2-4-kHz range to produce spectrally complex patterns. The tonal IOIs within the reference sequences were either equal (200 or 600 ms) or varied individually with an average value of 200 or 600 ms to produce temporally complex patterns. The difference limen (DL) for increments of IOI was measured. Comparison sequences featured either equal increments in all tonal IOIs or increments in a single target IOI, with the sequential location of the target changing randomly across trials. Four groups of younger and older adults with and without sensorineural hearing loss participated. Results indicated that DLs for uniform changes of sequence rate were smaller than DLs for single target intervals, with the largest DLs observed for single targets embedded within temporally complex sequences. Older listeners performed more poorly than younger listeners in all conditions, but the largest age-related differences were observed for temporally complex stimulus conditions. No systematic effects of hearing loss were observed.

Temporal detection in human vision: dependence on stimulus energy.

We have previously proposed and evaluated an economical model of human performance in tasks requiring spatiotemporal signal detection in spatiotemporal noise [Vision Research (to be published)]. The model was successful in describing human psychophysical performance and provides a means for comparing temporal filters (mechanisms) employed under different stimulus conditions. We present investigations into how estimates of temporal mechanisms depend on the contrast energy of the stimulus. Temporal-sensitivity changes result in covariation of the cutoff and peak frequencies of the low-pass and bandpass mechanisms, respectively, with stimulus energy. The results indicate that sensitivity to high temporal frequencies increases as stimulus energy increases, commensurate with extent physiological evidence in cat and primate.

Outer-retina locus of increased flicker sensitivity of the peripheral retina.

We tested alternative hypotheses concerning the locus of enhanced flicker sensitivity observed in response to stimuli presented to the peripheral retina. The first hypothesis attributes increased temporal frequency sensitivity to ganglion cell and higher-order neural processing, whereas the second hypothesis states that the locus of these temporal effects is at the cone photoreceptors. To test these alternative hypotheses we measured retinal electrophysiological and psychophysical temporal modulation thresholds. We found that sensitivity for temporal frequencies < 30 Hz did not vary as a function of retinal location for either the focal electroretinogram (ERG) or the psychophysical measure. However, for both measures, sensitivity for temporal frequencies > or = 30 Hz was greater in the peripheral retina than in the central retina. In addition, critical flicker frequency for the central retina was linear as a function of retinal illuminance for both the psychophysical and the electrophysiological measures. For the peripheral retina the slopes of critical flicker frequency versus log illuminance functions were steeper than the central slopes for both threshold measures. Eccentrically measured focal ERG and psychophysical critical flicker frequency values showed a relative saturation, deviating from the linear slope above 3.5 log Td. The findings of similar focal ERG and psychophysical temporal sensitivity changes with eccentricity support an outer retinal origin of this phenomenon.

Temporal changes in the sensitivity of Neisseria gonorrhoeae to penicillin in Edinburgh, Scotland.

Increased resistance of Neisseria gonorrhoeae to penicillin has been reported from many centres around the world since the introduction of antibiotic therapy in the 1940s. This study reports the temporal changes in gonococcal penicillin sensitivity over a 3-year period. All patients with a diagnosis of gonorrhoea in the city of Edinburgh, Scotland between 1990 and 1992 were included in the study. Penicillin sensitivity of isolates was analysed in relation to the sex and sexual orientation of the patient and the antibiotic therapy given. Four hundred and twenty-seven new patient episodes of infection occurred of which penicillin sensitivities were available in 426. Eleven episodes of PPNG infection occurred. Chromosomally mediated penicillin resistance did not increase over the study period. No differences were evident in the sensitivity of isolates from homosexual and heterosexual patients. Unlike many other areas the relative resistance of N. gonorrhoeae is not increasing in Edinburgh at present. This may relate to local antibiotic policies combined with intrinsic characteristics of N. gonorrhoeae itself. Unlike previous reports there did not appear to be any increased resistance to penicillin in isolates from gay men.

Selective inactivation of muscarinic M2 and M3 receptors in guinea-pig ileum and atria in vitro.

1. The role of muscarinic M2 and M3 receptors in ileal smooth muscle has been evaluated by use of selective receptor alkylation. The alkylating agents, 4-diphenylacetoxy-N-(2-chloroethyl)-piperidine (4-DAMP mustard) was studied for effects against (+)-cis-dioxolane, at muscarinic M2 and M3 receptors in guinea-pig atria or ileum, respectively. 4-DAMP mustard (10 nM, 40 min exposure) did not discriminate between these muscarinic receptors. In ileum, 4-DAMP mustard, at 100 nM, resulted in a large dextral shift (197 fold) and depression in maxima. In atria there was a smaller dextral shift (14 fold) but no depression in maxima. 2. The muscarinic antagonists, atropine (non-selective), methoctramine (M2-selective) and para-fluorohexahydro-siladiphenidol (pFHHSiD; M3 selective) were studied in protection studies against alkylation by phenoxybenzamine. Washout studies following equilibration of the tissues with atropine (30 nM), methoctramine (0.3 microM) or pFHHSiD (3 microM), showed the compounds to be reversible. No temporal changes in sensitivity to (+)-cis-dioxolane were observed. 3. Exposure, for 20 min, of atria and ileum to phenoxybenzamine (3 and 10 microM respectively) caused dextral shifts and depressions in the maxima of the concentration-response curve to (+)-cis-dioxolane. These effects were inhibited by prior equilibration with atropine (30 nM) and methoctramine (0.1 microM) in atria or atropine (30 nM) and pFHHSiD (3 microM) in ileum. Similar results in ileum were obtained when pilocarpine was used as the agonist. 4. These data were consistent with muscarinic M2 receptors mediating responses in atria and M3 receptors mediating responses in ileum. No evidence was provided for a direct role of muscarinic M2 receptors in ileal contraction.5. It is concluded that receptor protection by reversible antagonists for muscarinic M2 or M3 receptors provides a means to isolate pharmacologically a single subtype in a tissue possessing heterogeneous populations. This technique may prove useful in defining the role of the respective subtypes in smooth muscle contraction.

Temporal frequency dependent adaptation at the level of the outer retina in humans

The focal electroretinogram (FERG) was used to examine temporal frequency tuning at the outer retinal level in humans by measuring temporal modulation thresholds. Changes in FERG thresholds as a function of ambient light level were compared to temporal modulation thresholds obtained psychophysically using the same stimuli. At lower temporal frequencies, both FERG and psychophysical thresholds changed sensitivity proportional to the mean illuminance level. At higher illuminance levels, both threshold measures were relatively independent of illuminance. The comparison of the FERG to the behavioral data suggest that most of the adaptation-dependent changes in temporal sensitivity in humans occur at the level of the photoreceptor complex.

Sustained-attention capacity in young and older adults.

The sustained-attention capacity of young (21-29 years) and older (65-78 years) adults was examined using a high-event rate digit-discrimination vigilance task presented at three levels of stimulus degradation. Increased stimulus degradation led to a reduction in the hit rate and to a greater decline in hit rate over blocks (increased vigilance decrement). Sensitivity (d') declined over blocks only at the highest level of stimulus degradation. Older adults had a lower hit rate and showed greater vigilance decrement than young adults, particularly when stimuli were highly degraded. However, both age groups showed the same pattern of stability in sensitivity when stimulus degradation was moderate, and sensitivity decrement over time when stimulus degradation was high. The results suggest that the process of sustained allocation of capacity--as reflected in temporal changes in sensitivity--operates similarly in young and older adults.

Temporal changes in sensitivity of muscarinic receptors of rat jejunal smooth muscle following myenteric plexus ablation

Temporal changes in sensitivity of muscarinic receptors of rat jejunal smooth muscle following myenteric plexus ablation

Temporal changes in sensitivity of muscarinic receptors of rat jejunal smooth muscle following myenteric plexus ablation

Temporal changes in sensitivity of muscarinic receptors of rat jejunal smooth muscle following myenteric plexus ablation

Gestational changes in the level of glucocorticoid-binding sites in fetal bovine cartilaginous tissues.

In order to assess glucocorticoid actions on fetal cartilage development, [3H]dexamethasone binding site levels in fetal bovine cartilaginous tissues from long bones were measured, using a whole cell assay at 37 degrees C. Displaceable [3H]dexamethasone binding in epiphysial growth cartilage was maximal (16.2 fmol/10(6) cells) in fetuses of 10-15 cm crown-rump length (CR), and declined to 22% of the maximum in fetuses of 20-30 cm CR. Subsequently, [3H]dexamethasone binding rose to a plateau (13.0 fmol/10(6) cells) in fetuses of 30-80 cm CR and declined in those of 80-100 cm CR. When measured in growth plate cartilage, [3H]dexamethasone binding was significantly higher in fetuses of 40-80 cm CR (39 fmol/10(6) cells) than in those of 80-100 cm CR. There was no significant change of [3H]dexamethasone binding affinities in epiphysial chondrocytes of 5-100 cm CR fetuses or in growth plate chondrocytes of 40-100 cm CR fetuses. These results demonstrate that fetal cartilaginous tissues during development possess varying cellular levels of glucocorticoid binding and may thus have temporal changes in sensitivity to glucocorticoid hormones.