Since 1997 we have been developing a theoretical foundation for general anaesthesia. We have been able to demonstrate that the abrupt change in brain state brought on by anaesthetic drugs can be ...characterized as a first-order phase transition in the population-average membrane voltage of the cortical neurons. The theory predicts that, as the critical point of phase change into unconsciousness is approached, the electrical fluctuations in cortical activity will grow strongly in amplitude while slowing in frequency, becoming more correlated both in time and in space. Thus the bio-electrical change of brain-state has deep similarities with thermodynamic phase changes of classical physics. The theory further predicts the existence of a second critical point, hysteretically separated from the first, corresponding to the return path from comatose unconsciousness back to normal responsiveness. There is a steadily accumulating body of clinical evidence in support of all of the phase-transition predictions: low-frequency power surge in EEG activity; increased correlation time and correlation length in EEG fluctuations; hysteresis separation, with respect to drug concentration, between the point of induction and the point of emergence.
Transient surge absorption capability of supercapacitors is practically implemented in a commercial surge protector known as supercapacitor assisted surge absorber (SCASA). It is a low component ...count high performance circuit design which utilizes a coupled inductor topology wound to a powdered-iron magnetic core. This paper investigates non-ideal characteristics of the SCASA transformer designed using various air-gapped ferrites such as manually gapped toroids and mass-produced commercially available EER cores. Emphasis is given to examine surge energy losses associated with leakage magnetic field and fringing flux of gapped transformer prototypes. In predicting effects of an air gap in ferrite materials, an analytical approach based on effective-permeance is used with validations based on SCASA inductance properties. Experimental work presented in this paper are carried out using a Noiseken lightning surge simulator adhering to IEC 60038 and IEEE C62.41 standards. In addition, SCASA prototypes were subjected to surge immunity tests specified by UL-1449 Underwriters' laboratory procedures, where a 10% reduction of load-voltage was recorded outperforming the present design.
The purposes of this study were to (1) longitudinally examine US college and university COVID-19 dashboard content and (2) explore county-level population health and COVID-19 community indicators ...where colleges with large undergraduate enrollments were located.
We identified 10 colleges with the largest undergraduate enrollments. Next, we located all public and private two- and four-year nonprofit colleges (n = 58) in each respective county. We assessed active COVID-19 dashboards using established criteria from We Rate COVID Dashboards in March 2021 and February 2022.
In 2021 and 2022, two-thirds (n = 38/58) of colleges had an active COVID-19 dashboard. While most COVID-19 dashboards were easy to read, they were less likely to include updated daily infection rates and testing frequency details.
Overall quality, content, and features of COVID-19 dashboards varied greatly across colleges. Future COVID-19 dashboard designs should focus on providing evidence-based information with the goal of promoting and supporting informed decision making.
Background. Previous studies suggest that the occurrence of pre-eclampsia is seasonally distributed. This retrospective study aims to determine whether there is a seasonal variation in the number of ...admissions and the prevalence of women with pre-eclampsia in Tygerberg Hospital, South Africa. Methods. The number of women admitted with a diagnosis of pre-eclampsia, eclampsia or haemolysis elevated liver enzymes low platelets (HELLP) syndrome (together called pre-eclampsia) was obtained from hospital records from 2002 to 2003 for each season and month. Associations were analysed with Odds Ratios (OR). Furthermore, these data was compared with the Cape Town temperatures recorded on each day over the period, as well as the total rainfall for each month. Bivariate logistic regression of the probability of pre-eclampsia on temperature and rainfall was performed. Results. Pre-eclampsia occurred in 11.5% of all admissions (1,329/11,585). The prevalence was highest in winter (13.6% pre-eclampsia patients from all admissions). Women admitted in winter had a higher risk of developing pre-eclampsia compared to those admitted in summer (OR =1.69, 95% CI: 1.07-1.53). The risk of developing pre-eclampsia in June was higher than in February (summer in South Africa, reference month) (OR =2.81, 95% CI: 2.06-3.83). There was a significant correlation between the number of admissions with pre-eclampsia and the minimum daily temperature (r=−0.620, p=0.032). Conclusions. Pre-eclampsia occurs more frequently in winter at Tygerberg Hospital, South Africa. The findings have implications for future research related to the aetiology of pre-eclampsia as well as for clinical care.
A new method is presented for the extraction of mixed layer depth and entrainment zone thickness from lidar, backscatter ratio profiles. The method is based on fitting a four parameter, idealized ...profile to observed profiles. Optimization of the fit yields values for mixed layer depth and entrainment zone thickness. Since the fitting procedure is based on the entire measured profile, it has a robustness not found in methods based on critical backscatter or backscatter gradient. The method is tested by application to four measured profiles and three synthetic profiles. The sets of profiles include some that are very demanding because of small mixed layer to upper layer backscatter ratio contrasts, or have plumes of high backscatter imbedded in mixed and upper layers. It is shown that the method is robust and simple to implement, even for a sequence of independent profiles.
In electric and hybrid electric vehicles, series-connected battery packs are commonly used. Should the state-of-health (SOH) of one or several individual cells deteriorate, the entire battery pack is ...affected, reducing battery pack capacity, which in turn reduces the maximum distance able to be driven. In order to predict the SOH of the individual battery cells, this paper introduces the concept of effective battery capacitance. Effective capacitance is defined as the local slope of the voltage versus charge curve derived from a third-order polynomial relationship between these parameters. The location of maximum effective capacitance can be used as a means of identifying end-of-life and/or catastrophic failure of battery modules. Four different Toyota Prius battery packs were used in establishing this method in the proof of concept work. This paper presents a linear relationship between maximum effective capacitance and SOH; this relationship is confirmed with a larger dataset.
The novel coronavirus SARS-CoV-2, responsible for the present COVID-19 global pandemic, is known to bind to the angiotensin converting enzyme-2 (ACE2) receptor in human cells. A possible treatment of ...COVID-19 could involve blocking ACE2 and/or disabling the spike protein on the virus. Here, molecular dynamics simulations were performed to test the binding affinities of nine candidate compounds. Of these, three drugs showed significant therapeutic potential that warrant further investigation: SN35563, a ketamine ester analogue, was found to bind strongly to the ACE2 receptor but weakly within the spike receptor-binding domain (RBD); in contrast, arbidol and hydroxychloroquine bound preferentially with the spike RBD rather than ACE2. A fourth drug, remdesivir, bound approximately equally to both the ACE2 and viral spike RBD, thus potentially increasing risk of viral infection by bringing the spike protein into closer proximity to the ACE2 receptor. We suggest more experimental investigations to test that SN35563-in combination with arbidol or hydroxychloroquine-might act synergistically to block viral cell entry by providing therapeutic blockade of the host ACE2 simultaneous with reduction of viral spike receptor-binding; and that this combination therapy would allow the use of smaller doses of each drug.
Communicated by Ramaswamy H. Sarma
A scaling analysis is conducted to explore the dependence of sea-breeze speed and inland occurrence in the presence of opposing winds on a set of dynamical parameters. The overall aim of the analysis ...is to develop an index for sea-breeze occurrence in the face of opposing winds, similar to the Biggs and Graves lake-breeze index. Most studies separate sea-breeze speed and sea-breeze inland occurrence or, at best, link the two in linear analyses. This work analyzes the output of a nonlinear numerical mesoscale model (in idealized simulations) using scaling methods commonly applied in observational studies. It is found that the scaled sea-breeze speed, in response to increasing magnitude of opposing wind, shows two distinct phases: a phase of increasing speed while the sea breeze progresses inland and a phase of sharply decreasing speed when the sea breeze is no longer detected inland. The analysis also allows the development of an index for sea-breeze inland occurrence. This index is an improvement over existing analyses through the use of nonlinear scaling and the use of surface heat flux as opposed to simpler land–sea temperature contrasts.
A source-area model for estimating population exposure to air pollutants at the scale of a neighborhood is developed. The model explicitly accounts for the first-order influence of atmospheric ...dispersion of emissions on surface concentrations. The model is used to produce concentration surfaces at high spatial and temporal resolution, and is calibrated using measurements from a fixed monitoring network and evaluated against measurements from two intensive measurement campaigns. The source area model is compared against a fixed buffer model that ignores meteorological dispersion. The source area model captures the influence of wind speed, wind direction and stability on the dispersion and advection of emissions, and thereby achieves modest improvement of performance over the fixed buffer model. The model is useful for the determination of personal exposures and health effects to local emissions.
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