scholarly journals Two alternative scenarios for easing COVID-19 lockdown measures: one reasonable and one catastrophic

2020 ◽  
Author(s):  
A.S. Fokas ◽  
J. Cuevas-Maraver ◽  
P. G. Kevrekidis
Keyword(s):  
Time Evolution ◽  
Incubation Period ◽  
Epidemiological Models ◽  
Sick Person ◽  
Current State ◽  
First Case ◽  
Mathematical Equations ◽  
Alternative Scenarios ◽  
Two Parameters ◽  
Existing Data

We consider two sub-populations consisting of individuals below or above 40 years of age, which will be referred to as “young” and “older”. A person infected with SARS-CoV-2, following an incubation period, will become either sick (with COVID-19) or will be asymptomatic; the latter will recover, whereas a sick person will either recover or will be hospitalized where they will either die or recover. We assume that the interaction between a person who is infected and a person with the capacity to be infected is described by the usual mechanism of the standard epidemiological models. We first show that by choosing appropriately the parameters of the mathematical equations describing the dynamics of the above sub-populations in data stemming from Greece, one can obtain a reasonable match of the existing data for the time evolution of the total number of deaths and infections for both subpopulations during the current state of lockdown. Then, we consider two possible alternatives: first, we keep the two parameters describing the interactions of older-older and older-young as they are now, but we increase the value of the parameter describing the interaction of young-young; this means that we allow the lockdown measures to be eased only in the young sub-population. Second, we increase the values of all the three above parameters, which means we ease the lockdown measures in both sub-populations. In the first case, the number of deaths remains relatively small, whereas in the second case the situation, upon sufficient increase of the number of contacts, may become catastrophic potentially leading to a dramatic loss of lives.

The method of determining the metrological performance of unit reference standards of reflection coefficient in waveguides at millimeter waves

2020 ◽  
pp. 59-63
Author(s):  
A.S. Bondarenko ◽  
A.S. Borovkov ◽  
I.M. Malay ◽  
V.A. Semyonov
Keyword(s):  
Reflection Coefficient ◽  
Millimeter Waves ◽  
Primary Standard ◽  
Reference Standards ◽  
Measurement Scale ◽  
Current State ◽  
Coefficient Measurement ◽  
Mathematical Equations ◽  
Electrodynamic Modeling ◽  
Metrological Performance

The analysis of the current state of the reflection coefficient measurements in waveguides at millimeter waves is carried out. An approach for solving the problem of reproducing the reflection coefficient measurement scale is proposed. Mathematical equations, which are the basis of the reflection coefficient measurement equation are obtained. The method of determining the metrological performance of reflection coefficient unit’s reference standards is developed. The results of electrodynamic modeling and analytical calculations by the developed method are compared. It is shown that this method can be used for reproducing the reflection coefficient unit in the development of the State primary standard.

Derivation Mathematical Equations for Future Calculation of Potential Evapotranspiration in Iraq, A Review of Application of Thornthwaite Evapotranspiration

2019 ◽  
Vol 60 (5) ◽  
pp. 1037-1048
Author(s):  
Hussein Ilaibi Zamil Al-Sudani
Keyword(s):  
Water Balance ◽  
Potential Evapotranspiration ◽  
Coefficient Of Determination ◽  
Research Review ◽  
Climate Conditions ◽  
Average Temperature ◽  
Mean Temperature ◽  
Mathematical Equations ◽  
Two Parameters ◽  
The Relationship

     In any natural area or water body, evapotranspiration is one of the important outcomes in the water balance equation. As a significant method and depending on monthly average temperature, estimating of potential Evapotranspiration depending on Thornthwaite method was adopted in this research review. Estimate and discuss evapotranspiration by using Thornthwaite method is the main objectives of this research review with considerable details as well as compute potential evapotranspiration based on climatologically data obtained in Iraq. Temperature - evapotranspiration relationship can be estimated between those two parameters to reduce cost and time and facilitate calculation of water balance in lakes, river, and hydrogeological basins. The relationship was obtained using Thornthwaite method in Iraq by dividing the area into seven sectors according to geographic latitude. Each sector has multi meteorological stations where thirty two stations were used with different periods of records. A mathematical relationship was obtained between mean temperature and corrected potential evapotranspiration with (97.45) to (99.84) coefficient of determination. The mean temperature has a decreasing pattern from southern east towards northern west of Iraq affected by Mediterranean Sea climate conditions, while corrected potential evapotranspiration has the opposite direction regarding increased value because of a direct relationship with temperature.

Catholic Thought and Intellectual Property: Learning from the Ethics of Obligation

2009 ◽  
Vol 25 (2) ◽  
pp. 415-451 ◽  
Author(s):  
Gabriel J. Michael
Keyword(s):  
Intellectual Property ◽  
Global Health ◽  
Twelfth Century ◽  
Ethical Obligation ◽  
Medical Technologies ◽  
Sick Person ◽  
Current State ◽  
Alive Today ◽  
The Law ◽  
Ethical Obligations

The twelfth century canon lawyer Gratian once wrote “Feed the man dying of hunger, because if you have not fed him you have killed him.” If Gratian were alive today, he might take a look at the current state of global health and say, “Succor the woman dying of disease, because if you have not helped her you have killed her.” Both of these statements express an ethical obligation: if I have food, and someone else who is hungry does not, I am obligated to share my food. Likewise, if I have medicine, and someone else who is sick does not, I am obligated to share my medicine.Unfortunately, with regard to medicines and other essential products, modern institutions of intellectual property often fail to enforce or even recognize such ethical obligations. In some ways, these institutions uphold an even harsher attitude toward intellectual property than other types of property. With food, even if the hungry person receives no bread, he is still permitted to produce his own. With medicines, medical technologies, and other types of goods that are protected by institutions of intellectual property, the law can and often does prevent the sick person from producing her own.

Mechanics of Interactions of Helices in Proteins

2006 ◽  
Vol 326-328 ◽  
pp. 823-826
Author(s):  
Li Li Xin ◽  
Gregory S. Chirikjian
Keyword(s):  
Rigid Body ◽  
Protein Structures ◽  
Body Motion ◽  
Data Sets ◽  
Line Contact ◽  
Helical Structures ◽  
First Case ◽  
Rigid Rods ◽  
On Line ◽  
Two Parameters

This paper concerns a mechanics of interactions of helical structures in proteins. Helices are the most important secondary structures of proteins and contribute the formation of a more complex 3-D structure, and so the analysis of interactions of helices is quite critical. We examine 1290 protein structures that have 2.0 Å or better resolutions and less than 20 percent of their sequences in common. Interactions between helices are represented by two parameters: the distance and angle. Assuming that helices are slender rigid rods with finite length, we define three different mechanisms of interactions: (1) line-on-line contact; (2) endpoint-to-line contact; and (3) endpointto- endpoint contact. In this paper, interactions for the first case are expressed with the 3-D relative rigid-body motion (position and orientation) and the unique volume element for correctly integrating over rigid-body motions are determined using six parameters. The results are extremely useful for the correct analysis of interactions in terms of distance and angle without the statistical biases inherent in the three data sets.

scholarly journals Predictive accuracy of a hierarchical logistic model of cumulative SARS-CoV-2 case growth until May 2020

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Levente Kriston
Keyword(s):  
Disease Transmission ◽  
Logistic Model ◽  
Predictive Accuracy ◽  
Future Research ◽  
Cumulative Number ◽  
Epidemiological Models ◽  
First Case ◽  
Distribution Of Resources ◽  
The One ◽  
Models Of Disease

Abstract Background Infectious disease predictions models, including virtually all epidemiological models describing the spread of the SARS-CoV-2 pandemic, are rarely evaluated empirically. The aim of the present study was to investigate the predictive accuracy of a prognostic model for forecasting the development of the cumulative number of reported SARS-CoV-2 cases in countries and administrative regions worldwide until the end of May 2020. Methods The cumulative number of reported SARS-CoV-2 cases was forecasted in 251 regions with a horizon of two weeks, one month, and two months using a hierarchical logistic model at the end of March 2020. Forecasts were compared to actual observations by using a series of evaluation metrics. Results On average, predictive accuracy was very high in nearly all regions at the two weeks forecast, high in most regions at the one month forecast, and notable in the majority of the regions at the two months forecast. Higher accuracy was associated with the availability of more data for estimation and with a more pronounced cumulative case growth from the first case to the date of estimation. In some strongly affected regions, cumulative case counts were considerably underestimated. Conclusions With keeping its limitations in mind, the investigated model may be used for the preparation and distribution of resources during the initial phase of epidemics. Future research should primarily address the model’s assumptions and its scope of applicability. In addition, establishing a relationship with known mechanisms and traditional epidemiological models of disease transmission would be desirable.

scholarly journals Does Holmium laser enucleation of the prostate (HoLEP) still have a steep learning curve? Our experience of 100 consecutive cases from Turkey

2021 ◽  
Vol 93 (4) ◽  
pp. 412-417
Author(s):  
Güçlü Gürlen ◽  
Kadir Karkin
Keyword(s):  
Learning Curve ◽  
Medical Treatment ◽  
Prostate Volume ◽  
Holmium Laser ◽  
Steep Learning Curve ◽  
First Case ◽  
Laser Enucleation ◽  
The Mean ◽  
Two Parameters ◽  
Holmium Laser Enucleation

Aim: The aim of our study is to examine the learning curve of HoLEP and to discuss our results in the light of the literature. Methods: 100 patients who had LUTS resistant to medical treatment and complicated BPH to whom HoLEP procedure had been administered regardless of the size of the prostate in the last 1 year were analysed retrospectively. To evaluate the learning curve, the patients were classified into 4 main groups of 25 consecutively operated patients beginning from the first case. The 4 main groups were divided into 2 subgroups including patients who had prostate volume below or above 80 grams. Results: The mean age of the 100 patients who had HoLEP was 64.5 years. The mean prostate volume was 99.1 cc (45-281 cc). When those with prostate smaller than 80 g are examined, Enucleation efficiency was 0.76 g/min (0.46-0.97 g/min) and Morcellation efficiency was 3.07 g/min (3.34-4 g/min). When those with prostates larger than 80 g are examined, Enucleation efficiency was 0.89 g/min (0.66-1.04 g/min) and Morcellation efficiency was 4.01 g/min (3.93-4.25 g/min). These two parameters were statistically and significantly different in all the 4 groups (p < 0.05). Conclusions: HoLEP still has a steep learning curve. It is necessary to reach the number of cases of 25-50 to reach fundamental experience.

scholarly journals Low-power latch comparator with accurate hysteresis control

2020 ◽  
Vol 71 (6) ◽  
pp. 379-387
Author(s):  
Leïla Khanfir ◽  
Jaouhar Mouïne
Keyword(s):  
Cmos Technology ◽  
Control Voltage ◽  
Dynamic Comparator ◽  
Silicon Area ◽  
Current State ◽  
First Case ◽  
Control Devices ◽  
Dynamic Comparators ◽  
Analog Voltage ◽  
Hysteresis Control

AbstractRecent research has focused on finding ways to control hysteresis of dynamic comparators. The current proposed techniques are based on either geometrical dimension adjustment or digital control. The first case does not allow for post fabrication control, while the second has limited accuracy. This paper presents a new dynamic comparator design with external hysteresis adjustment using an analog voltage. This is achieved by proposing an architecture including control devices with a specific sizing. This is performed with no significant increase of the design complexity, keeping the power consumption as low as possible. The design is analyzed, showing that the proposed solution allows accurate hysteresis adjustment without affecting the inherent circuit properties. The dynamic comparator is also implemented using a 180 nm commercially available CMOS technology. The results show that a variation of 550 mV of the control voltage allows an accurate hysteresis adjustment ranging from 0 to 40 mV, according to the input conditions. Moreover, the simplicity of the circuit in conjunction with the use of dynamic technology have allowed the best performances to be achieved compared to the current state of the art, in terms of energy with an FoM equal to 116 fJ/decision and silicon area of 180 µm2 .

scholarly journals Male-mediated maturation in a wild primate

2020 ◽  
Author(s):  
Amy Lu ◽  
Jacob A. Feder ◽  
Noah Snyder-Mackler ◽  
Thore J. Bergman ◽  
Jacinta C. Beehner
Keyword(s):  
Head Start ◽  
Fetal Loss ◽  
Father Absence ◽  
Early Puberty ◽  
Immature Female ◽  
Father Presence ◽  
Bruce Effect ◽  
First Case ◽  
Reproductive Male ◽  
Alternative Scenarios

AbstractIn humans, a controversial hypothesis suggests that father absence promotes early puberty in daughters. Data from rodents confirm females accelerate maturation with exposure to novel males (“Vandenbergh effect”) and delay it with exposure to male relatives. Here, we report the first case of male-mediated maturation in a wild primate, geladas (Theropithecus gelada). Females were more likely to mature after a change in the reproductive male: some matured earlier than expected (Vandenbergh effect) and some later (due to father presence). Novel males stimulated a surge in estrogens for all immature females - even females too young to mature. Although male-mediated puberty accelerated first births, the effect was modest, suggesting that alternative scenarios, such as co-evolution with the Bruce effect (male-mediated fetal loss) may explain this phenomenon.One Sentence SummaryNovel males induce an estrogen surge, male-mediated puberty, and a head-start on reproduction for immature female geladas.

scholarly journals Valuation of harvested goods in Mida Creek with application of the TESSA approach

2021 ◽  
Vol 19 (2) ◽  
pp. 105-115
Author(s):  
Cecilia O. Olima ◽  
Paul K. Muoria ◽  
Margaret A. Owuor
Keyword(s):  
Ecosystem Services ◽  
Quantitative Data ◽  
Descriptive Statistics ◽  
Site Specific ◽  
Simplified Approach ◽  
Spatial Methods ◽  
Current State ◽  
Ecosystem Service Valuation ◽  
Alternative Scenarios ◽  
Business As Usual

Mangroves are considered a highly productive blue forests resource providing services that are important to the community both locally and globally. In recent times there has been an increase in studies on valuation of ecosystem services provided by mangroves. However, there is need to provide a simplified approach to identify, assess and quantify ecosystem services. In this study the Toolkit for Ecosystem Services Site-based Assessment (TESSA) was used to assess the value of harvested goods provided by the mangroves of Mida Creek in the current state and under plausible alternative scenarios. Spatial methods (GIS) were used to collect data for the period 1985-2019, and household interviews were used to collect data on harvested goods. Descriptive statistics were used to summarize quantitative data. Results show that the estimated current annual value of harvested goods in Mida Creek is US$ 11.2 million. This value increased to US$ 14.3 million under the conservation scenario and reduced to US$ 10.9 million under the business as usual scenario (BAU). These findings add to the growing literature on ecosystem service valuation and the need to use site-specific non-modelling tools like TESSA.

Esthetic Rehabilitation With Nanohybrid Composite: Case Report Series

2020 ◽  
Vol 11 (2) ◽  
pp. 251-256
Author(s):  
Shazeena Qaiser ◽  
Darshana Devadiga ◽  
Mithra N Hegde
Keyword(s):  
State Of The Art ◽  
Case Reports ◽  
Cost Effective ◽  
Composite Resins ◽  
Class Iii ◽  
Current State ◽  
First Case ◽  
High Smoothness ◽  
Nanohybrid Composite ◽  
Recent Addition

Composite resins represent the current state of the art in the field of restorative materials, for they present a standard aesthetic potential with satisfactory durability and are less cost-effective than a comparable ceramic restoration. The most recent addition to this is a nanohybrid direct composite that demonstrates exceptional handling properties and superior aesthetics. These series of case reports illustrate the three different scenarios where nanohybrid composite was used as a direct restorative material owing to its high smoothness and favorable mechanical properties; the first case being the fracture of an upper lateral incisor, second of Class IV caries in upper central incisors, and lastly the discolored restoration and Class III caries in upper central incisors. The nanohybrids used provided an acceptable color match in all the three cases with a conservative technique and were relatively easy to maintain.

Sign in / Sign up

Export Citation Format

Share Document