Steeper Rate Research Articles

(117) Characterizing Fibrofog in Daily Life: Ambulatory Cognitive Functioning in Adults with Fibromyalgia and Matched Controls

Most people with fibromyalgia (FM) report “fibrofog”, or cognitive dysfunction. To better characterize fibrofog in daily life, we conducted an ambulatory study of subjective and objective cognitive function in real-world settings in persons with FM and sex-, age-, and education-matched healthy controls (HC) to test whether: 1) people with FM demonstrate poorer cognitive function on ambulatory measures; 2) people with FM demonstrate a different diurnal pattern of cognitive function; and 3) subjective cognitive function corresponds more highly with objective cognitive measures in HC compared to FM. Participants (N=102; nFM=50; nHC=52) completed ecological momentary assessments of perceived cognitive function (perceived clarity and speed) on a numerical rating scale of 0-100 and cognitive tests of processing speed (Symbol Search) and working memory (Dot Matrix) via a smartphone app at 5 quasi-random times/day for 8 days. The FM group scored significantly lower than HC on measures of self-reported cognitive functioning, as well as on objective measures of processing speed and working memory. Results from multilevel models showed that both groups demonstrated similar diurnal patterns for objective measures of working memory, which was stable across the day, and objective processing speed, which was slowest at wake- and bed-times and fastest midday. For both groups, perceived cognitive dysfunction was highest upon waking and improved across the day; however, the HC group showed a significantly steeper rate of improvement. Perceived cognitive dysfunction corresponded only with processing speed, not working memory, and there were no group differences in these associations. Findings for ambulatory subjective and objective cognitive function in FM are generally consistent with findings from lab-based studies; the FM group demonstrated relatively worse cognitive functioning, but diurnal patterns and associations between objective/subjective functioning were similar to HC.

A STUDY ON ETIOLOGICAL PROFILE IN ADULTS WITH ACUTE FEBRILE ENCEPHALOPATHY IN A TERTIARY CARE CENTRE IN EASTERN INDIA

Background: Acute febrile encephalopathy is a common clinical syndrome across the globe with the principal cause and manifestations differing according to the demographics. In developing nations like India primary central nervous system infections is the chief culprit.
 Aim: To identify the etiology of acute febrile encephalopathy and to document the clinical manifestations on presentation. The patients were followed up till discharge and outcome was analyzed in relation with etiology.
 Materials & Methods: This observational prospective study was done among 50 patients presenting with fever and altered mental status. History, clinical examination, biochemical investigations including cerebrospinal fluid analysis and neuroimaging was done to diagnose the cases individually. The statistical software SPSS version 2.0 was used for the analysis Categorical variables were expressed as number of patients or percentage of patients and compared across the groups using Pearson’s Chi Square test for independence of attributes. Continuous variables was expressed as mean and standard deviation and compared across the groups using Kruskal Wallis Test. An alpha level of 5% was taken, i.e. if any p value is less than 0.05 it was considered as significant.
 Results: Out of these 50 patients 70% were due to CNS infections among which viral meningoencephalitis were the commonest cause. The other causes were leptospirosis, brain abscess, cerebral malaria, sepsis associated encephalopathy, acute disseminated encephalomyelitis, neuroleptic malignant syndrome. 14% of patients had sepsis associated encephalopathy and these patients had the highest mortality
 Conclusion: Acute febrile encephalopathy is a clinically heterogeneous syndrome with a number of causes. It is an important public health issue due to its steep mortality rate.
 Keywords: acute febrile encephalopathy, meningoencephalitis, mortality, sepsis associated encephalopathy

The role of national rural health mission in reducing infant mortality rate in India

PurposeThe purpose of this paper is to assess the role of National Rural Health Mission (NRHM) in reducing Infant Mortality in India. The study will help the government in deciding its future course of action regarding the infant mortality rate (IMR) reduction in India.Design/methodology/approachThis paper adopts the interrupted time series analysis (ITSA) approach with a control group to study the role of NRHM in reducing the IMR in India. The authors examined infant mortality in rural areas of India for the level and trend change before and after the implementation of NRHM. The authors then applied a suitable ARMA model to estimate the coefficients of the regression model. From the estimated results, the study predicts the counterfactuals for both the rural IMR and urban IMR and plots the results.FindingsThe study found the evidence supporting the hypotheses that the NRHM has led to a reduction in the difference between urban IMR and rural IMR. The research shows that the rural IMR declined at steeper rates in the post-NRHM period (2005–2015).Originality/valueNone of the existing studies analyses the impact of a social scheme like NRHM on the reduction of IMR in India by applying the ITSA. The study is unique as it estimates the counterfactuals and plots the results which show the impact of NRHM on reducing IMR.

Parameter identification of dc black‐box arc model using non‐linear least squares

The black-box arc model is known to be a useful technique to simulate dynamic arc-circuit interaction by reflecting arc characteristics. Existing researches have shown that the black-box model has been widely used to analyse the ac arc characteristics of SF6 and air circuit breakers. Due to the enormous energy and steep rise rate (di/dt) during dc fault, it is important to consider dc arc characteristics. However, there are no examples of black-box models for dc circuit breakers utilised in railway systems and dc microgrid. In this study, the applicability of the black-box model, which was applied to the existing ac arc analysis, was verified for the dc arc analysis. Black-box modelling is applied to datasheet of industrial low-voltage circuit breakers and parametric sweep method was used to select Schwarz model parameters considering the tendency of dc arc current waveform for the dc pole-to-pole fault. The authors also applied the Levenberg–Marquardt algorithm, which is the most extensively used for the optimisation of functional parameters, to the Schwarz model for accurate and reliable arc modelling. As a result, the dc arc feasibility of the black-box model was analysed through simulation results, and a model optimisation technique was proposed.

Kinematic and thermodynamic conditions related to convective systems with a bow echo in Poland

Severe wind events are often related to the occurrence of mesoscale convective systems with arch-shaped radar reflectivity, i.e., a bow echo. In this research, the kinematic and thermodynamic conditions associated with 91 bow echo cases which occurred in the warm season (i.e., from early April until late September) in Poland (2007–2014) were analyzed. The environmental conditions were determined primarily based on the upper air soundings, and additionally on data obtained from ERA-Interim reanalysis. The results indicate that there is a relatively wide range of shear and instability environments associated with bow echoes over Poland. The identified cases occurred both in weakly forced environments, and as well developed in dynamic synoptic patterns with low instability. We have also found cases with strong instability and significantly increased shear values. The combination of a moist boundary layer and steep mid-tropospheric lapse rate usually resulted in moderate to high CAPE values for identified bow echo cases. The median of surface-based CAPE was equal to 1594 J/kg (Mean Layer CAPE = 1038 J/kg) for soundings, and to 1622 J/kg (Mean Layer CAPE = 1275 J/kg) for ERA-Interim. Bow echo environments also showed significantly increased potential for strong downdrafts and damaging outflow winds (the median Downdraft CAPE reached 849 J/kg for soundings and 734 J/kg for ERA-Interim). Bow echoes were usually associated with the occurrence of strong air flow in the troposphere. The presence of a jet stream in the middle and upper troposphere contributed to the development of increased vertical wind shear values. The median of 0–6-km shear exceeded 15 m/s, whereas for 0–3-km shear, it was approximately equal to 12.5 m/s and to 7 m/s for 0–1-km shear.

Wideband microstrip band stop filters realization with interdigital topologies

This article proposes novel wide band stop filter topologies at C-band with simpler implementation in microstrip. The introduction interdigital resonator along with stepped impedance resonator concept is utilized for the placement of transmission zeros to achieve wideband performances. This article demonstrates fractional bandwidth of > 80% with steep skirt rate. This topology is modified further to achieve improved out of band performance. The parallel coupled section for input and output signal coupling results in improved out of band performances. The measured 3-dB bandwidth is from 4 to 10 GHz and transmission loss below 0.55 dB is achieved for both the topologies. Close analogies between simulated and measured results is obtained which are detailed in this article. The presented topologies are simpler and novel achieving the desired performances without vias.

S76. A BEHAVIOURAL ECONOMIC ANALYSIS OF EFFORT-RELATED CHOICE IN SCHIZOPHRENIA

BackgroundMotivational deficits are prevalent feature of schizophrenia, which have been tightly linked to real-world outcomes. Abnormalities in effort cost computations have been proposed as a candidate mechanism underlying these deficits. In the present study, we sought to employ behavioural economic analyses to further understand cost-benefit decision making abnormalities in schizophrenia.Methods58 young adults with schizophrenia and 58 matched controls participated in this study. Participants completed an effort-based decision-making task in which they made decisions to expend physical effort in exchange for monetary rewards. From participants choice behaviour, we computed indifference values (i.e. the reward value at which participants would be indifferent to expending effort vs not) for each individual participant. Other computational parameters were also computed such as choice consistency and subjective reward valuation.ResultsPatents and controls did not differ in their subjective valuation of reward. On the decision-making task, patients made more inconsistent choices relative to controls. In both univariate and multivariate analyses controlling for potential confounders, patients had higher indifference values meaning that patients required more money in the exchange of their effort. Among patients, higher indifference values were associated with more severe clinical motivational deficits.DiscussionPatients had multiple abnormalities related to their decisions to expend effort for reward. Choices were more chaotic and reward value was discounted by effort at a steeper rate in patients. These results point toward an abnormality in the computation of effort costs or in the integration of these costs with value signals.

Air and wet bulb temperature lapse rates and their impact on snowmaking in a Pyrenean ski resort

A set of 17 air temperature and relative humidity sensors were used to analyze the temporal variability of surface air temperature (Tair), wet bulb temperature (Twb), and daily snowmaking hours (SM, number of hours per day with Twb < − 2 °C), lapse rates, and the occurrence of thermal inversions at the Formigal ski resort (Spanish Pyrenees) from December to March during three consecutive ski seasons (2012–2013, 2013–2014, and 2014–2015). The Tair and Twb lapse rates showed strong hourly and daily variability, with both exhibiting almost identical temporal fluctuations. The Twb exhibited average lapse rates that were slightly steeper (− 5.2 °C/km) than those observed for Tair (− 4.9 °C/km). The less steep lapse rates and most thermal inversions were observed in December. Days having less (more) steep Tair and Twb lapse rates were observed under low (high) wind speeds and high (low) relative humidity and air pressure. The temporal dynamics of the SM lapse rates was more complex, as this involved consideration of the average Tair in the ski resort, in addition to the driving factors of the spatio-temporal variability of Twb. Thus, on a number of cold (warm) days, snowmaking was feasible at all elevations at the ski resort, independently of the slopes of the lapse rates. The SM exhibited an average daily lapse rate of 8.2 h/km, with a progressive trend of increase from December to March. Weather types over the Iberian Peninsula tightly control the driving factors of the Tair, Twb, and SM lapse rates (wind speed, relative humidity, and Tair), so the slopes of the lapse rates and the frequency of inversions in relation to elevation for the three variables are very dependent on the occurrence of specific weather types. The less steep lapse rates occurred associated with advections from the southeast, although low lapse rates also occurred during advections from the east and south, and under anticyclonic conditions. The steepest Tair and Twb lapse rates were observed during north and northwest advections, while the steepest rates for SM were observed during days of cyclonic circulation and advections from the northeast.

Modeling the burden of cardiovascular disease in Turkey.

Objective:This study aims to estimate the current and future burden of cardiovascular diseases (CVD) in Turkey.Methods:A burden-of-disease model was developed that included inputs on population growth, prevalence, and incidence of ischemic disease (IHD) and cerebrovascular disease (CeVD), prevalence of modifiable risk factors, mortality rates, and relationship between risk factors and IHD/CeVD. Direct costs to the public health-care system and indirect costs from lost production due to premature mortality, hospitalizations, disability, and absenteeism were considered.Results:We estimated that in 2016, 3.4 million Turkish adults were living with CVD, including 2.5 million affected by IHD, and 0.9 million by CeVD. This prevalence is projected to increase to 5.4 million by 2035. The economic burden of CVD was estimated at US$10.2 billion in 2016, projected to increase twofold to US$19.4 billion by 2035.Conclusion:Our study confirms that the current burden of CVD is significant, and that it is projected to increase at a steep rate over the next two decades. This growing burden of disease will likely create significant pressure on the public health-care system in the form of direct health-care costs, as well as on society in the form of lost productivity.

A Balanced Feed Filtering Antenna With Novel Coupling Structure for Low-Sidelobe Radar Applications

A fourth-order filtering patch antenna with a novel coupling structure is presented in this paper. Using the proposed coupling structure, both the balanced coupling feed and cross-coupling are realized. Two identical slots etched on the ground plane are utilized to excite the radiating patch with the reduced cross-polarization level. A short slot etched on the ground plane is employed for cross-coupling, which introduces two controllable radiation nulls with a steep roll-off rate. In addition, owing to the split-ring resonators and hairpin resonators, the improved impedance bandwidth is achieved with the fourth-order filtering response. To demonstrate the proposed design techniques, both the filtering antenna element and the low-sidelobe array are designed, fabricated, and measured. The measured results show that the proposed antenna has the impedance bandwidth of 12% (4.78–5.39 GHz) with the total height of $0.06\lambda _{0}$ , the cross-polarization level lower than −31 dB, and two radiation nulls with the suppression higher than 31 dB. For the low-sidelobe antenna array, wide impedance bandwidth is also obtained with the sidelobe level below −28.7 dB, the cross-polarization level below −34 dB, and the out-of-band suppression better than 25 dB.

Water-Injection Operations and Gas-Injection Sensitivities in the Bakken Formation

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 185030, “Improved Oil Recovery in Tight Oil Formations: Results of Water-Injection Operations and Gas-Injection Sensitivities in the Bakken Formation of Southeast Saskatchewan,” by S.M. Ghaderi, C.R. Clarkson, and A. Ghanizadeh, University of Calgary, and K. Barry and R. Fiorentino, Crescent Point Energy, prepared for the 2017 SPE Canada Unconventional Resources Conference, Calgary, 15–16 February. The paper has not been peer reviewed. Although improvement in hydraulic-fracture properties and infill drilling remains the focus of recovery enhancement from the Bakken, low oil recoveries and steep initial decline rates are experienced in primary-recovery operations, even after application of multifractured-horizontal-well technology. Therefore, many pilots have been executed to determine the viability of waterflooding for maintaining oil rates and improving recoveries through reservoir-pressure maintenance and sweep-efficiency enhancement. This paper presents the performance results from one of the waterflood pilots in the Viewfield Bakken. Numerical-Model Setup A section of the Bakken reservoir (the geology of which is described in detail in the complete paper) deemed to be representative of the waterflood performance in Viewfield is considered for modeling. This section has been developed by use of multifractured horizontal wells completed in the Middle Bakken (main target reservoir) with a well spacing of 200 m (eight wells per section, named A through H). All eight wells started oil production within a similar time frame, and, after approximately 1 year of production, every other well was converted to a water injector. Reservoir-Fluid Model. Conventional pressure/volume/temperature (PVT) analysis was conducted by a commercial laboratory on 12 surface-separator oil and gas samples. Recombination of fluids at reservoir temperature (156.2°F) yields a final gas/oil ratio of 810 scf/STB. Subsequently, a series of constant-composition-expansion and differential-liberation tests was conducted on the recombined fluid to determine oil-saturation pressure, oil-formation-volume factor, oil density, and oil and gas viscosity as a function of pressure. The Peng-Robinson equation of state and modified Pedersen viscosity correlation were tuned to replicate the PVT properties of oil and gas as a function of pressure. Reservoir Grid Model. On the basis of the well tops and reservoir net-pay values, reservoir structure for the study area was generated. It is known that the minimum horizontal stress is aligned in the northwest direction and at approximately 50° with respect to the east/west horizon. Therefore, reservoir gridding is rotated at this angle to mimic the hydraulic-fracture orientation along the horizontal-well laterals. Grid size in the horizontal direction is 65×65 ft, and the total thickness of the reservoir is approximately 28 ft, which is divided into nine layers of equal thickness.

Addressing Climate Change Through Infrastructure R&amp;R

It seems that unless a community's water systems have recently failed or a steep rate hike is imminent, protecting and improving these systems is marginalized to a degree. When water services are consistently acceptable or better, it's much easier to prioritize the proverbial grease for other squeaky wheels. But quality and reliability have costs, and water systems that don't meet expectations in these areas will ultimately present their communities with bills that invite more than squeaking. As a nexus between service and cost, a utility should regularly communicate not just the quality of the water it delivers but also the state of its assets and any projected needs and threats on the horizon.

Abstract 125: Elevated Muscle Sympathetic Nerve Activity is Associated With Higher Aortic and Carotid Stiffness Independent of Blood Pressure in Women

Central arterial stiffness, a significant contributor to the development of hypertension and cardiovascular disease with aging, is linked to elevated muscle sympathetic nerve activity (MSNA) in men. However, the extent to which MSNA is associated with central arterial stiffness in women is unknown. Given that the age-related increase in MSNA and arterial blood pressure (BP) occurs at a steeper rate among women compared to men, we tested the hypothesis that resting MSNA is more strongly correlated with central arterial stiffness in women than in men. Also, because of the parallel age-related increase in MSNA, we further hypothesized that the relation between MSNA and central arterial stiffness would not be independent of age. MSNA (microneurography), aortic stiffness (carotid-femoral pulse wave velocity, CFPWV), and carotid β-stiffness (carotid tonometry and ultrasound) were assessed in 54 healthy men (n=29; 19-72 yrs; 30 ± 1 kg/m 2 ; systolic BP: 128 ± 3 mmHg) and women (n=26; 26-64 yrs; 29 ± 2 kg/m 2 ; systolic BP: 116 ± 3 mmHg). No differences between men and women were observed for CFPWV (Men: 7.0 ± 0.3 vs. Women: 6.8 ± 0.4 mmHg, P=0.747) and carotid β-stiffness (Men: 7.6 ± 0.8 vs. Women: 7.6 ± 0.5 mmHg, P=0.975). Mean BP was lower in women compared to men (Men: 93 ± 3 vs. Women: 85 ± 2 mmHg, P=0.021) and MSNA tended to be lower in women compared to men (Men: 25 ± 3 vs. Women: 20 ± 2 bursts/min, P=0.091). After adjusting for mean BP and HR (partial correlation), CFPWV was significantly correlated with MSNA in men (R=0.44, P=0.021) and women (R=0.58, P=0.004). Interestingly, further adjustment for age abolished the association between CFPWV and MSNA in men (R=0.01, P=0.968), but not in women (R=0.43, P=0.046). A moderate relation between carotid β-stiffness and MSNA was observed in men (R=0.37, P=0.063) and women (R=0.44, P=0.034), but was abolished after adjusting for age (Men: R=-0.001, P=0.995; Women: R=0.26, P=0.245). These preliminary data demonstrate that MSNA is positively correlated with central arterial stiffness in women and men independent of BP. Furthermore, abolishment of the relation between MSNA and CFPWV in men only when adjusting for age suggests that the association between MSNA and central arterial stiffness may be more robust in women.

Regularization of Ill-Posed Point Neuron Models

Point neuron models with a Heaviside firing rate function can be ill-posed. That is, the initial-condition-to-solution map might become discontinuous in finite time. If a Lipschitz continuous but steep firing rate function is employed, then standard ODE theory implies that such models are well-posed and can thus, approximately, be solved with finite precision arithmetic. We investigate whether the solution of this well-posed model converges to a solution of the ill-posed limit problem as the steepness parameter of the firing rate function tends to infinity. Our argument employs the Arzelà–Ascoli theorem and also yields the existence of a solution of the limit problem. However, we only obtain convergence of a subsequence of the regularized solutions. This is consistent with the fact that models with a Heaviside firing rate function can have several solutions, as we show. Our analysis assumes that the vector-valued limit function v, provided by the Arzelà–Ascoli theorem, is threshold simple: That is, the set containing the times when one or more of the component functions of v equal the threshold value for firing, has zero Lebesgue measure. If this assumption does not hold, we argue that the regularized solutions may not converge to a solution of the limit problem with a Heaviside firing function.

Sounding-Derived Parameters Associated with Convective Hazards in Europe

Abstract Observed proximity soundings from Europe are used to highlight how well environmental parameters discriminate different kind of severe thunderstorm hazards. In addition, the skill of parameters in predicting lightning and waterspouts is also tested. The research area concentrates on central and western European countries and the years 2009–15. In total, 45 677 soundings are analyzed including 169 associated with extremely severe thunderstorms, 1754 with severe thunderstorms, 8361 with nonsevere thunderstorms, and 35 393 cases with nonzero convective available potential energy (CAPE) that had no thunderstorms. Results indicate that the occurrence of lightning is mainly a function of CAPE and is more likely when the temperature of the equilibrium level drops below −10°C. The probability for large hail is maximized with high values of boundary layer moisture, steep mid- and low-level lapse rates, and high lifting condensation level. The size of hail is mainly dependent on the deep layer shear (DLS) in a moderate to high CAPE environment. The likelihood of tornadoes increases along with increasing CAPE, DLS, and 0–1-km storm-relative helicity. Severe wind events are the most common in high vertical wind shear and steep low-level lapse rates. The probability for waterspouts is maximized in weak vertical wind shear and steep low-level lapse rates. Wind shear in the 0–3-km layer is the best at distinguishing between severe and extremely severe thunderstorms producing tornadoes and convective wind gusts. A parameter WMAXSHEAR multiplying square root of 2 times CAPE (WMAX) and DLS turned out to be the best in distinguishing between nonsevere and severe thunderstorms, and for assessing the severity of convective phenomena.

IQ as moderator of terminal decline in perceptual and motor speed, spatial, and verbal ability: Testing the cognitive reserve hypothesis in a population-based sample followed from age 70 until death.

Terminal decline (TD) refers to acceleration in within-person cognitive decline prior to death. The cognitive reserve hypothesis postulates that individuals with higher IQ are able to better tolerate age-related increase in brain pathologies. On average, they will exhibit a later onset of TD, but once they start to decline, their trajectory is steeper relative to those with lower IQ. We tested these predictions using data from initially nondemented individuals (n = 179) in the H70-study repeatedly measured at ages 70, 75, 79, 81, 85, 88, 90, 92, 95, 97, 99, and 100, or until death, on cognitive tests of perceptual-and-motor-speed and spatial and verbal ability. We quantified IQ using the Raven's Coloured Progressive Matrices (RCPM) test administrated at age 70. We fitted random change point TD models to the data, within a Bayesian framework, conditioned on IQ, age of death, education, and sex. In line with predictions, we found that 1 additional standard deviation on the IQ scale was associated with a delay in onset of TD by 1.87 (95% highest density interval [HDI; 0.20, 4.08]) years on speed, 1.96 (95% HDI [0.15, 3.54]) years on verbal ability, but only 0.88 (95% HDI [-0.93, 3.49]) year on spatial ability. Higher IQ was associated with steeper rate of decline within the TD phase on measures of speed and verbal ability, whereas results on spatial ability were nonconclusive. Our findings provide partial support for the cognitive reserve hypothesis and demonstrate that IQ can be a significant moderator of cognitive change trajectories in old age. (PsycINFO Database Record

Predictors and mechanisms of conversion to psychosis

Summary Background: Identifying predictors and elucidating mechanisms underlying onset of psychosis are critical for the development of preventive interventions. Methods: This paper reviews findings on risk prediction algorithms and potential mechanisms of onset in youth at clinical high-risk for psychosis. Results: An independently validated individualized risk calculator is available that incorporates risk factors from clinical, demographic, neurocognitive, and psychosocial assessments to predict likelihood of conversion to psychosis among individuals who meet criteria for a prodromal risk syndrome. At risk individuals who convert to psychosis show a steeper rate of gray matter reduction, most prominent in prefrontal cortex, compared with those who do not. Higher levels of pro-inflammatory cytokines at baseline predicted the accelerated reduction in prefrontal gray matter. These same markers are associated with microglial-mediated synaptic pruning and dendritic retraction in animal models. Conclusions: Processes that modulate microglial activation, such as dysregulated immune function and deficient synaptic plasticity, may represent convergent mechanisms that influence brain dysconnectivity and risk for onset of psychosis.

Relating Wind and Stress under Tropical Cyclones with Scatterometer

AbstractOcean surface stress, the turbulent transport of momentum, is largely derived from wind through a drag coefficient. In tropical cyclones (TCs), scatterometers have difficulty measuring strong wind and there is large uncertainty in the drag coefficient. This study postulates that the microwave backscatter from ocean surface roughness, which is in equilibrium with local stress, does not distinguish between weather systems. The reduced sensitivity of scatterometer wind retrieval algorithms under the strong wind is an air–sea interaction problem that is caused by a change in the behavior of the drag coefficient rather than a sensor problem. Under this assumption, a stress retrieval algorithm developed over a moderate wind range is applied to retrieve stress under the strong winds of TCs. Over a moderate wind range, the abundant wind measurements and the more established drag coefficient value allow for sufficient stress data to be computed from wind to develop a stress retrieval algorithm for the scatterometer. Using 0.9 million coincident stress and wind pairs, the study shows that the drag coefficient decreases with wind speed at a much steeper rate than previously revealed, for wind speeds over 25 m s−1. The result implies that the ocean applies less drag to inhibit TC intensification, and that TCs cause less ocean mixing and surface cooling than previous studies indicated.

Ill-Posed Point Neuron Models.

We show that point-neuron models with a Heaviside firing rate function can be ill posed. More specifically, the initial-condition-to-solution map might become discontinuous in finite time. Consequently, if finite precision arithmetic is used, then it is virtually impossible to guarantee the accurate numerical solution of such models. If a smooth firing rate function is employed, then standard ODE theory implies that point-neuron models are well posed. Nevertheless, in the steep firing rate regime, the problem may become close to ill posed, and the error amplification, in finite time, can be very large. This observation is illuminated by numerical experiments. We conclude that, if a steep firing rate function is employed, then minor round-off errors can have a devastating effect on simulations, unless proper error-control schemes are used.

High Solar Flux Concentration Water Splitting with Hematite (α‐Fe2O3) Photoanodes

Reference EPFL-ARTICLE-216288doi:10.1002/aenm.201500817View record in Web of Science Record created on 2016-02-16, modified on 2017-12-03