scholarly journals R 0 estimation for COVID‐19 pandemic through exponential fit

2021 ◽  
Author(s):  
Zheng Mingliang ◽  
Theodore E. Simos ◽  
Charalampos Tsitouras
Keyword(s):  
Exponential Fit

Sickness induced by head movements after different centrifugal Gx-loads and durations

2008 ◽  
Vol 17 (5-6) ◽  
pp. 323-332
Author(s):  
Suzanne A.E. Nooij ◽  
Jelte E. Bos
Keyword(s):  
Short Duration ◽  
Time Constant ◽  
Head Movement ◽  
Head Movements ◽  
Symptom Intensity ◽  
Space Adaptation Syndrome ◽  
Space Adaptation ◽  
Exponential Fit

It has been found that sustained centrifugation on Earth may evoke sickness symptoms that are similar to those of the Space Adaptation Syndrome (SAS). As in SAS, incidence of this 'Sickness Induced by Centrifugation' (SIC) is about 50% and the symptoms are particularly evoked by head movements. By systematically varying the G-load and duration of centrifugation, the current study investigated the characteristics of the gravitational stimulus that is required for SIC to occur. Subjects were exposed to centrifugation at 2 and 3Gx, for a duration of 45 and 90 minutes. A standardized head movement protocol was used to evoke SIC after centrifugation. The results show that in six out of 12 subjects (50%) no serious symptoms were elicited. In the remaining subjects, the effects of the 3G runs exceeded those of the 2G runs, and within each G-level symptom intensity was higher for the 90 min than for the 45 min exposure. An exponential fit on this data showed that the time constant of adaptation to the gravitational stimulus was about 60 minutes. This suggests that short duration exposures (i.e. < 60 min) are not likely to induce serious SIC.

Exponential fit to high energy π - p scattering at fixed angle

1967 ◽  
Vol 24 (11) ◽  
pp. 551-553 ◽  
Author(s):  
H. Burkhardt ◽  
K.T. Ng
Keyword(s):  
High Energy ◽  
Fixed Angle ◽  
Exponential Fit

Exponential fit of QT interval-heart rate relation during exercise used to diagnose stress-induced myocardial ischemia

1991 ◽  
Vol 24 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Massimo Ciavolella ◽  
Paolo Emilio Puddu ◽  
Michele Schiariti ◽  
Cristina Ciani ◽  
Elena Cerquetani ◽  
...  
Keyword(s):  
Heart Rate ◽  
Myocardial Ischemia ◽  
Qt Interval ◽  
Rate Relation ◽  
Exponential Fit

Diffusion-Corrected Sigma Using Dual Exponential Fit for Time-Lapse Reservoir Monitoring

2020 ◽  
Author(s):  
Shaikha Al-Turkey ◽  
Daniel Freile ◽  
Larisa Tagarieva ◽  
Mohamed Elyas ◽  
Gregory Schmid
Keyword(s):  
Time Lapse ◽  
Reservoir Monitoring ◽  
Exponential Fit

SPIN GLASS DYNAMICS ON A HIERARCHICAL TREE

1993 ◽  
Vol 07 (01n03) ◽  
pp. 980-985 ◽  
Author(s):  
R. ORBACH ◽  
M. LEDERMAN
Keyword(s):  
Spin Glass ◽  
Spin Glasses ◽  
Time Window ◽  
Branching Ratio ◽  
Temperature Cycling ◽  
Small Range ◽  
Hierarchical Tree ◽  
Ultrametric Tree ◽  
Glass Dynamics ◽  
Exponential Fit

The configuration space of spin glasses is characterized by the existence of quasidegenerate equilibrium states separated by barriers, ∆(T). A temperature cycling protocol allows extraction of the temperature dependence of a specific barrier. We find ∂∆(T)/∂T depends only on the particular value of ∆(T) and not on the temperature. Using either a power law or an exponential fit (either is equally accurate), integration leads to a divergence of ∆(T) at a particular temperature T* as the temperature decreases, characteristic of the particular barrier considered. This is interpreted as a continuous divergence of barriers as the temperature is lowered, beginning at Tg. Between these divergent barriers, barriers of finite height exist. The time decay of the thermoremanent magnetization at measurement times t much greater than the waiting time tw is a measure of the correlation of the spin glass at time t with the field-cooled state. Using ultrametricity, this enables the extraction of the branching ratio of the “tree” according to which the spin glass states are organized. Experiments are interpreted in terms of a constant branching ratio for the ultrametric tree within the (small) range of overlaps accessible because of the experimental time window.

Temperature Dependence of Electric Conductivities in Femtosecond Laser Modified Areas in Silicon Carbide

2014 ◽  
Vol 778-780 ◽  
pp. 661-664 ◽  
Author(s):  
Manato Deki ◽  
Tomoki Oka ◽  
Shodai Takayoshi ◽  
Yoshiki Naoi ◽  
Takahiro Makino ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Femtosecond Laser ◽  
Temperature Dependence ◽  
Specific Resistance ◽  
Laser Modification ◽  
Current Voltage ◽  
Double Exponential ◽  
Current Voltage Characteristics ◽  
Exponential Fit

Temperature dependence of the femtosecond laser modified region on silicon carbide was measured. The current-voltage characteristics showed the ohmic properties and thus we could evaluate the specific resistance for each irradiation conditions and the measured temperatures. The specific resistance was increased with decreasing temperature. From the double exponential fit to the temperature dependence of the specific resistance, the trapping energy of the impurity levels formed by the femtosecond laser modification was found to be 4.5 meV and 51.4 meV.

Absorbed dose estimates from a single measurement one to three days after the administration of 177Lu-DOTATATE/-TOC

2017 ◽  
Vol 56 (06) ◽  
pp. 219-224 ◽  
Author(s):  
Constantin Lapa ◽  
Andreas Buck ◽  
Michael Lassmann ◽  
Rudolf Werner ◽  
Heribert Hänscheid
Keyword(s):  
Absorbed Dose ◽  
Measured Data ◽  
The Other ◽  
Single Measurement ◽  
Fixed Tissue ◽  
Tissue Specific ◽  
Time Integral ◽  
Activity Concentrations ◽  
Planar Images ◽  
Exponential Fit

SummaryAim: To retrospectively analyze the accuracy of absorbed dose estimates from a single measurement of the activity concentrations in tumors and relevant organs one to three days after the administration of 177Lu-DOTA-TATE/TOC assuming tissue specific effective half-lives. Methods: Activity kinetics in 54 kidneys, 30 neuroendocrine tumor lesions, 25 livers, and 27 spleens were deduced from series of planar images in 29 patients. After adaptation of mono- or bi-exponential fit functions to the measured data, it was analyzed for each fit function how precise the time integral can be estimated from fixed tissue-specific half-lives and a single measurement at 24, 48, or 72 h after the administration. Results: For the kidneys, assuming a fixed tissue-specific half-life of 50 h, the deviations of the estimate from the actual integral were median (5 % percentile, 95 % percentile): -3 °% (-15 %>; +16 °%) for measurements after 24 h, +2 %> (-9 %>; +12 %>) for measurements after 48 h, and 0 % (-2 %; +12 %) for measurements after 72 h. The corresponding values for the other tissues, assuming fixed tissue-specific half-lives of 67 h for liver and spleen and 77 h for tumors, were +2 % (-25 %; +20 %) for measurements after 24 h, +2 °% (-16 %>; +17 %>) for measurements after 48 h, and +2 %> (-11 %>; +10 %>) for measurements after 72 h. Conclusions: Especially for the kidneys, which often represent the dose limiting organ, but also for liver, spleen, and neuroendocrine tumors, a meaningful absorbed dose estimate is possible from a single measurement after 2, more preferably 3 days after the administration of 177Lu-DOTA-TATE/-TOC assuming fixed tissue specific effective half-lives.

scholarly journals Time-resolved spectroscopy of the ensembled photoluminescence of nitrogen- and boron/nitrogen-doped carbon dots

2018 ◽  
Vol 20 (17) ◽  
pp. 11673-11681 ◽  
Author(s):  
Sunghu Kim ◽  
Byung-Kuk Yoo ◽  
Yuri Choi ◽  
Byeong-Su Kim ◽  
Oh-Hoon Kwon
Keyword(s):  
Exponential Decay ◽  
Carbon Dots ◽  
Surface States ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Nitrogen Doped ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon ◽  
Boron Nitrogen ◽  
Exponential Fit

The non-exponential decay of the photoluminescence of carbon dots are analyzed using stretched exponential fit functions to reflect the heterogeneity in their luminescent surface states.

Determining the number of terms in a Prony algorithm exponential fit

1977 ◽  
Vol 36 (3-4) ◽  
pp. 319-332 ◽  
Author(s):  
John N. Holt ◽  
Robyn J. Antill
Keyword(s):  
Prony Algorithm ◽  
Exponential Fit
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