Spatially explicit seasonal forecasting using fuzzy spatiotemporal clustering of long-term daily rainfall and temperature data

International audienceA major limitation of statistical forecasts for specific weather station sites is that they are not spatial in the true sense. And while spatial predictions have been studied, their results have indicated a lack of seasonality. Global Circulation Models (GCMs) are spatial, but their spatial resolution is rather coarse. Here we propose spatially explicit seasonal forecasting, based on the Fuzzy Classification of long-term (40 years) daily rainfall and temperature data to create climate memberships over time and location. Data were obtained from weather stations across south-east Australia, covering sub-tropical to arid climate zones. Class memberships were used to produce seasonal predictions using correlations with climate drivers and a regression rules approach. Therefore, this model includes both local climate feedback and the continental drivers. The developed seasonal forecasting model predicts rainfall and temperature reasonably accurately. The final 6-month forecast for average maximum temperature and rainfall produced relative errors of 0.89 and 0.56 and Pearson correlation coefficients of 0.83 and 0.82, respectively

Maintaining woodland tax records (1994)

Revised 3/94/5M

The Resonance in the B-P-a Reaction

The yield of alpha particles of range greater than 2 cms. from boron bombarded by protons has been studied as a function of bombarding energy in the range from 100 to 200 ekv, using a thin target, either methyl borate or boron trifluoride at pressures of 1 mm. of Hg. The yield vs. energy curve shows an approximately exponential rise on which is superposed a sharp (half breadth ~ 6 ekv) intense line at 150 ± ekv. There is some indication of a weaker and much broader line at 190 ekv. Number range curves are not yet available, but the appearance of pulses on the oscillograph screen leads us to suppose that the high yield (line) at 150 ekv is due to emission of a homogeneous long-range group

Distribution in Angle of Alpha Particles from Li7 + H1

We find the distribution of alpha particles from Li7 + H1 is not spherically symmetric, a result in disagreement with the conclusions of earlier investigators,1 who, however, worked at rather low energies only. Thick target data at energies as low as 150 ekv show the presence of a small cos2Θ term and may be represented by I(Θ) = 1 + .16 Cos2Θ while at 440 ekv the asymmetry is very marked, the data being well represented by I(Θ) = 1 + .7 Cos2 Θ. Because of the rapid increase of yield with energy, it is to be expected that thin target data will show a slightly but only slightly greater cos2 0 term. Preliminary thin target data appear to bear this out

Distribution on Angle of Alpha Particles from F19 + H1

The distribution in angle of long range alpha particles from fluorine bombarded by protons has been studied in the range 270 - 440 ekv. The distribution shows a very strong concentration in the forward direction. Intensity as a function of angle in the center of mass system may be represented by the equation I (Θ) = 1 + .77 CoS Θ + .17 CoS2 Θ for a bombarding energy of 375 ekv. The distribution shows little, if any, energy dependence and in particular is not observably different at 330 ekv bombarding energy. Targets were prepared by electrolyzing hydrogen fluoride on tantalum and were fairly thin, the apparent half width of the 330 ekv gamma ray line being 40 ekv or less

Investigating the Influences of Task Demand and Reward on Cardiac Pre-Ejection Period (PEP) Reactivity During a Speech-in-Noise Task

Objectives: Effort investment during listening varies as a function of task demand and motivation. Several studies have manipulated both these factors to elicit and measure changes in effort associated with listening. The cardiac pre-ejection period (PEP) is a relatively novel measure in the field of cognitive hearing science. This measure, which reflects sympathetic nervous system activity on the heart, has previously been implemented during a tone discrimination task but not during a speech-in-noise task. Therefore, the primary goal of this study was to explore the influences of signal to noise ratio (SNR) and monetary reward level on PEP reactivity during a speech-in-noise task. Design: Thirty-two participants with normal hearing (mean age = 22.22 years, SD = 3.03) were recruited at VU University Medical Center. Participants completed a Dutch speech-in-noise test with a single-interfering-talker masking noise. Six fixed SNRs, selected to span the entire psychometric performance curve, were presented in a block-wise fashion. Participants could earn a low (€0.20) or high (€5.00) reward by obtaining a score of ≥70% of words correct in each block. The authors analyzed PEP reactivity: the change in PEP measured during the task, relative to the baseline during rest. Two separate methods of PEP analysis were used, one including data from the whole task block and the other including data obtained during presentation of the target sentences only. After each block, participants rated their effort investment, performance, tendency to give up, and the perceived difficulty of the task. They also completed the need for recovery questionnaire and the reading span test, which are indices of additional factors (fatigue and working memory capacity, respectively) that are known to influence listening effort. Results: Average sentence perception scores ranged from 2.73 to 91.62%, revealing a significant effect of SNR. In addition, an improvement in performance was elicited by the high, compared to the low reward level. A linear relationship between SNR and PEP reactivity was demonstrated: at the lower SNRs PEP reactivity was the most negative, indicating greater effort investment compared to the higher SNRs. The target stimuli method of PEP analysis was more sensitive to this effect than the block-wise method. Contrary to expectations, no significant impact of reward on PEP reactivity was found in the present dataset. Also, there was no physiological evidence that participants were disengaged, even when performance was poor. A significant correlation between need for recovery scores and average PEP reactivity was demonstrated, indicating that a lower need for recovery was associated with less effort investment. Conclusions: This study successfully implemented the measurement of PEP during a standard speech-in-noise test and included two distinct methods of PEP analysis. The results revealed for the first time that PEP reactivity varies linearly with task demand during a speech-in-noise task, although the effect size was small. No effect of reward on PEP was demonstrated. Finally, participants with a higher need for recovery score invested more effort, as shown by average PEP reactivity, than those with a lower need for recovery score

Greasing the wheels or a spanner in the works?:Regulation of the cardiac sodium pump by palmitoylation

The ubiquitous sodium/potassium ATPase (Na pump) is the most abundant primary active transporter at the cell surface of multiple cell types, including ventricular myocytes in the heart. The activity of the Na pump establishes transmembrane ion gradients that control numerous events at the cell surface, positioning it as a key regulator of the contractile and metabolic state of the myocardium. Defects in Na pump activity and regulation elevate intracellular Na in cardiac muscle, playing a causal role in the development of cardiac hypertrophy, diastolic dysfunction, arrhythmias and heart failure. Palmitoylation is the reversible conjugation of the fatty acid palmitate to specific protein cysteine residues; all subunits of the cardiac Na pump are palmitoylated. Palmitoylation of the pump’s accessory subunit phospholemman (PLM) by the cell surface palmitoyl acyl transferase DHHC5 leads to pump inhibition, possibly by altering the relationship between the pump catalytic α subunit and specifically bound membrane lipids. In this review, we discuss the functional impact of PLM palmitoylation on the cardiac Na pump and the molecular basis of recognition of PLM by its palmitoylating enzyme DHHC5, as well as effects of palmitoylation on Na pump cell surface abundance in the cardiac muscle. We also highlight the numerous unanswered questions regarding the cellular control of this fundamentally important regulatory process

Social observation increases the cardiovascular response of hearing-impaired listeners during a speech reception task

Certain cardiovascular measures allow for distinction between sympathetic and parasympathetic nervous system activity. Applied during listening, these measures may provide a novel and complementary insight into listening effort. To date, few studies have implemented cardiovascular measures of listening effort and seldom have these included hearing-impaired participants. These studies have generally measured changes in cardiovascular parameters while manipulating environmental factors, such as listening difficulty. Yet, listening effort is also known to be moderated by individual factors, including the importance of performing successfully. In this study, we aimed to manipulate success importance by adding observers to the traditional laboratory set-up. Twenty-nine hearing-impaired participants performed a speech reception task both alone and in the presence of two observers. Auditory stimuli consisted of Danish Hearing in Noise Test (HINT) sentences masked by four-talker babble. Sentences were delivered at two individually adapted signal-to-noise ratios, corresponding to 50 and 80% of sentences correct. We measured change scores, relative to baseline, of pre-ejection period, two indices of heart rate variability, heart rate and blood pressure (systolic, diastolic, and mean arterial pressure). After each condition, participants rated their effort investment, stress, tendency to give up and preference to change the situation to improve audibility. A multivariate analysis revealed that cardiovascular reactivity increased in the presence of the observers, compared to when the task was performed alone. More specifically, systolic, diastolic, and mean arterial blood pressure increased while observed. Interestingly, participants’ subjective ratings were sensitive only to intelligibility level, not the observation state. This study was the first to report results from a range of different cardiovascular variables measured from hearing-impaired participants during a speech reception task. Due to the timing of the observers’ presence, we were not able to conclusively attribute these physiological changes to being task related. Therefore, instead of representing listening effort, we suggest that the increased cardiovascular response detected during observation reveals increased physiological stress associated with potential evaluation

Combining cardiovascular and pupil features using k-nearest neighbor classifiers to assess task demand, social context and sentence accuracy during listening

In daily life, both acoustic factors and social context can affect listening effort investment. In laboratory settings, information about listening effort has been deduced from pupil and cardiovascular responses independently. The extent to which these measures can jointly predict listening-related factors is unknown. Here we combined pupil and cardiovascular features to predict acoustic and contextual aspects of speech perception. Data were collected from 29 adults (mean  =  64.6 years, SD  =  9.2) with hearing loss. Participants performed a speech perception task at two individualized signal-to-noise ratios (corresponding to 50% and 80% of sentences correct) and in two social contexts (the presence and absence of two observers). Seven features were extracted per trial: baseline pupil size, peak pupil dilation, mean pupil dilation, interbeat interval, blood volume pulse amplitude, pre-ejection period and pulse arrival time. These features were used to train k-nearest neighbor classifiers to predict task demand, social context and sentence accuracy. The k-fold cross validation on the group-level data revealed above-chance classification accuracies: task demand, 64.4%; social context, 78.3%; and sentence accuracy, 55.1%. However, classification accuracies diminished when the classifiers were trained and tested on data from different participants. Individually trained classifiers (one per participant) performed better than group-level classifiers: 71.7% (SD  =  10.2) for task demand, 88.0% (SD  =  7.5) for social context, and 60.0% (SD  =  13.1) for sentence accuracy. We demonstrated that classifiers trained on group-level physiological data to predict aspects of speech perception generalized poorly to novel participants. Individually calibrated classifiers hold more promise for future applications