persistence time
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Author(s):  
Manish M

Abstract: Once John Lubbock rightfully propounded, “What we see depends mainly on what we look for”. Perfection is a just a illusion whereas Perception is the real vision. This “illusion” is based on inertia of human eye. Propeller clock is a special kind of circular LED display. It is making use of POV, a scientific phenomena termed as ‘Persistence of Vision’, which means that if something appears in the same spot consistently, at least 50-60 times per second, our brains think that it’s permanently there when it is not. The term ‘Persistence of Vision display’ or ‘POV display’ has been used for LED display devices that compose images by displaying one spatial portion at a time in rapid succession (for example, one column of pixels every few milliseconds). A two-dimensional POV display is often accomplished by means of rapidly moving a single row of LEDs along a linear or circular path. The effect is that the image is perceived as a whole by the viewer as long as the entire path is completed during the visual persistence time of the human eye. A further effect is often to give the illusion of the image floating in mid-air. This implementation will be a coordination of electrical, electronics and mechanical engineering. Keywords: Persistence of Vision, Arduino Nano, Micro-controller, Led’s, Propeller, POV


2021 ◽  
pp. 000486742110516
Author(s):  
Mark Taylor ◽  
Dante Dangelo-Kemp ◽  
Dennis Liu ◽  
Steve Kisely ◽  
Simon Graham ◽  
...  

Objectives: To evaluate the utilisation and persistence of antipsychotics for the treatment of schizophrenia in Australia. Methods: A retrospective study using the Australian Pharmaceutical Benefits Scheme database of a representative 10% sample. All adults with schizophrenia who were dispensed three or more supplies of oral (including clozapine) or long-acting injectable antipsychotics between 1 June 2015 and 31 May 2020 were included. Persistence time in treatment was evaluated using survival analysis and Cox hazard ratios. Results: In all, 26,847 adults with schizophrenia were studied. Oral second-generation antipsychotics were more frequently dispensed than the other antipsychotic groups studied. Median treatment persistence times were 18.3 months for second-generation antipsychotic long-acting injectables, 10.7 months for oral second-generation antipsychotics and were significantly lower for both formulations of first-generation antipsychotics at 5.2 months (long-acting injectables) and 3.7 months (oral). The median persistence time for clozapine was significantly longer than all other antipsychotics groups. Conclusions: Oral second-generation antipsychotics and second-generation antipsychotic long-acting injectables accounted for over 75% and 13% of all antipsychotics in Australia, respectively. Concerns over medication adherence and subsequent relapse have not translated into increased long-acting injectable usage despite their significantly longer persistence. Clozapine, the single most ‘persistent’ antipsychotic, was only used in 9% of people, although up to a third of all cases are likely to be treatment-resistant. Our data suggest clinicians should give consideration to the earlier use of second-generation antipsychotic long-acting injectables and clozapine, to ameliorate prognosis in schizophrenia.


Epidemiologia ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 325-337
Author(s):  
Fernando Vadillo

In this paper, we consider a stochastic epidemic model with two pathogens. In order to analyze the coexistence of two pathogens, we compute numerically the expectation time until extinction (the mean persistence time), which satisfies a stationary partial differential equation with degenerate variable coefficients, related to backward Kolmogorov equation. I use the finite element method in order to solve this equation, and we implement it in FreeFem++. The main conclusion of this paper is that the deterministic and stochastic epidemic models differ considerably in predicting coexistence of the two diseases and in the extinction outcome of one of them. Now, the main challenge would be to find an explanation for this result.


Author(s):  
Barath M ◽  
Chandan R. S ◽  
Maruthi R ◽  
Paramakrishnan N

An ultra-fast liquid chromatography (RP-UFLC) approach was processed for the estimation of ETR, which is quick, responsive, reliable, and inexpensive. Work on the Phenomenex Kinetex C18 column (250x 4,6mm. 5μ) was carried out with MeOH and acetonitrile in the mobile phase ratio of (60:40v/v) at 1.0mL/min. With a PDA detection system, the eluent was tracked at 311nm. ETR elutes at a persistence time of 3.226 min. The proposed method gives linearity of concentration from 1 to 5μg/mL, with the value of R2 at 0.9942%. For the proposed method, LOD and LOQ are measured as 0.02 and 0.073μg/mL. The pharmaceutical drug included acidic, alkaline, corrosion, Ultraviolet, and heat stress stipulations. The deterioration material was nicely resolved from ETR peaks, which showed the reliability of the process. The approach has been tested with respect to process adequacy, linearity, reliability, and robustness, as per ICH guidelines.


2021 ◽  
Vol 118 (27) ◽  
pp. e2103398118
Author(s):  
Jacopo Marchi ◽  
Michael Lässig ◽  
Aleksandra M. Walczak ◽  
Thierry Mora

The evolution of many microbes and pathogens, including circulating viruses such as seasonal influenza, is driven by immune pressure from the host population. In turn, the immune systems of infected populations get updated, chasing viruses even farther away. Quantitatively understanding how these dynamics result in observed patterns of rapid pathogen and immune adaptation is instrumental to epidemiological and evolutionary forecasting. Here we present a mathematical theory of coevolution between immune systems and viruses in a finite-dimensional antigenic space, which describes the cross-reactivity of viral strains and immune systems primed by previous infections. We show the emergence of an antigenic wave that is pushed forward and canalized by cross-reactivity. We obtain analytical results for shape, speed, and angular diffusion of the wave. In particular, we show that viral–immune coevolution generates an emergent timescale, the persistence time of the wave’s direction in antigenic space, which can be much longer than the coalescence time of the viral population. We compare these dynamics to the observed antigenic turnover of influenza strains, and we discuss how the dimensionality of antigenic space impacts the predictability of the evolutionary dynamics. Our results provide a concrete and tractable framework to describe pathogen–host coevolution.


2021 ◽  
Vol 9 ◽  
Author(s):  
Taylor M. Wilcox ◽  
Anthony Caragiulo ◽  
Joseph C. Dysthe ◽  
Thomas W. Franklin ◽  
Daniel H. Mason ◽  
...  

Jaguar (Panthera onca) are of conservation concern and occur at very low densities in the northern portion of their range in northern Mexico and the southwestern United States. Environmental DNA sampling to detect genetic material from drinking water may be an effective approach for jaguar detection in these arid landscapes. Here we develop a qPCR assay for the detection of jaguar mitochondrial DNA, show that large quantities of DNA (mean 66,820 copies/L) can be found in the drinking water of captive animals, and observe detectable levels of DNA (80 copies/L) in a wild habitat with known jaguar populations. We suggest that environmental DNA sampling may represent a useful, complementary sampling tool for detection of rare jaguars, although effective application would require careful consideration of DNA persistence time in the environment.


2021 ◽  
pp. 000370282110123
Author(s):  
Hemalaxmi Rajavelu ◽  
Nilesh J Vasa ◽  
Satyanarayanan Seshadri

A benchtop Laser-Induced Breakdown Spectroscopy (LIBS) is demonstrated to determine the elemental carbon content present in raw coal used for combustion in power plants. The spectral intensities of molecular CN and C2 emission are measured together with the atomic carbon (C) and other inorganic elements (Si, Fe, Mg, Al, Ca, Na, and K) in the LIBS spectrum of coal. The emission persistence time of C2 molecule emission is measured from the coal plasma generated by a nanosecond laser ablation with a wavelength of 266 nm in the Ar atmosphere. The emission persistence time of molecular C2 emission along with the spectral intensities of major ash elements (Fe, Si, Al, and Ca) and carbon emissions (atomic C, molecular CN, and C2) shows a better relationship with the carbon wt% of different coal samples. The calibration model to measure elemental carbon (wt%) is developed by combining the spectral characteristics (Spectral intensity) and the temporal characteristics (Emission persistence time of C2 molecule emission). The temporal characteristic studies combined with the spectroscopic data in the PLSR (Partial Least Square Regression) model has resulted in an improvement in the root mean square error of validation (RMSEV), and the relative standard deviation (RSD) is reduced from 10.86% to 4.12% and from 11.32% to 6.04%, respectively.


2021 ◽  
Author(s):  
Jacopo Marchi ◽  
Michael Lässig ◽  
Aleksandra M. Walczak ◽  
Thierry Mora

The evolution of many microbes and pathogens, including circulating viruses such as seasonal influenza, is driven by immune pressure from the host population. In turn, the immune systems of infected populations get updated, chasing viruses even further away. Quantitatively understanding how these dynamics result in observed patterns of rapid pathogen and immune adaptation is instrumental to epidemiological and evolutionary forecasting. Here we present a mathematical theory of co-evolution between immune systems and viruses in a finite-dimensional antigenic space, which describes the cross-reactivity of viral strains and immune systems primed by previous infections. We show the emergence of an antigenic wave that is pushed forward and canalized by cross-reactivity. We obtain analytical results for shape, speed, and angular diffusion of the wave. In particular, we show that viral-immune co-evolution generates a new emergent timescale, the persistence time of the wave’s direction in antigenic space, which can be much longer than the coalescence time of the viral population. We compare these dynamics to the observed antigenic turnover of influenza strains, and we discuss how the dimensionality of antigenic space impacts on the predictability of the evolutionary dynamics. Our results provide a rigorous and tractable framework to describe pathogen-host co-evolution.


2021 ◽  
pp. 002581722098060
Author(s):  
Isabella Aquila ◽  
Pietrantonio Ricci ◽  
Carlo Filippo Bonetta ◽  
Matteo Antonio Sacco ◽  
Federico Longhini ◽  
...  

The activity of the SARS-CoV-2 virus has not yet been studied in a post-mortem setting. The absence of these data has led to the prohibition of exposure of infected corpses during burial procedures. Our aim was to assess the virus’s persistence and the possibility of transmission in the post-mortem phase including autopsy staff. The sample group included 29 patients who were admitted to our Covid-19 Centre who died during hospitalisation and the autopsy staff. All the swabs were subjected to a one-step real-time reverse transcription polymerase chain reaction with cycle threshold (Ct) values. Swab collection was performed at 2 h, 4 h, 6 h, 12 h, over 24 since death. The following were the analysis of patients’ swabs: 10 cases were positive 2 h after death; 10 cases positive 4 h after death; 9 cases were found positive 6 h after death; 7 cases positive 12 h after death; 9 cases remained positive 24 h after death. The swabs performed on all the forensic pathologist staff on duty who performed the autopsies were negative. The choice to avoid rituals and the display of corpses before and at the burial procedures given appears cautiously valid due to the persistence of the SARS-CoV-2 virus in the post-mortem period. Although the caution in choosing whether or not to perform an autopsy on infected corpses is acceptable, not to perform autopsies is not biologically supported.


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