Evaluating Real-World COVID-19 Vaccine Effectiveness Using a Test-Negative Case-Control Design

It is important to assess the extent to which the real-world effectiveness of marketed vaccines is consistent with that observed in the clinical trials, and to characterize how well vaccines prevent COVID-19 symptoms. We conducted a modified test-negative design (TND) to evaluate the RW effectiveness of three COVID-19 vaccines by leveraging data from an on-going, US community-based registry. Vaccine effectiveness was examined in two ways: considering cases who (1) tested positive for COVID-19 (695 cases, 1,786 controls) and who (2) tested positive with at least one moderate/severe COVID-19 symptom (165 cases, 2,316 controls). Any vaccination (full or partial) was associated with a 95% reduction in the odds of having a positive COVID-19 test [adjusted odds ratio (aOR) = 0.05 (95% confidence interval (CI): 0.04, 0.06)]. Full vaccination was associated with an aOR of 0.03 (95% CI: 0.03, 0.05) while partial vaccination had an aOR of 0.08 (95% CI: 0.06, 0.12). Any vaccination was associated with a 71% reduction in the odds of testing positive and having at least one moderate/severe symptom (aOR=0.29 (95% CI: 0.20, 0.40)). High effectiveness was observed across all three vaccine manufacturers both for prevention of positive COVID-19 test results and prevention of moderate/severe COVID-19 symptoms.

Comparative techno-economic analysis of power system with and without renewable energy sources

<p>The primary aim of this work is to feature the advantages of integrating natural source of energy from the solar and wind to the prevailing electric power systems. Two types of analysis are carried out in two test systems (standard and modified test systems) and the outcome of the test systems are compared. The two analyses are technical analysis and economic analysis. The stability of the voltage is analyzed under technical analysis and the price of energy consumed from the electric grid is calculated and analyzed under the economic analysis. Dynamic hourly load data, hourly solar radiation, hourly wind velocity, and dynamic electricity prices are considered for the standard IEEE system and modified test system (with the integration of RES). Voltage stability index (L-Index) and price of the electricity consumed from electric grid are found for standard test system and the outcome is compared with the outcome of modified test systems. MATLAB coding is done for techno-economic analysis for both test systems. It is inferred from the outcome that the integration of renewable energy sources fairly contributes to the economic benefit of the system by lowering the power purchased from the grid and enhance the stability of the system.</p>

Underlying variables in the understanding of movement in engineering students

This article describes the understanding of motion by active students taking Newtonian physics for engineering, supported by active learning, during the pandemic due to COVID-19; in addition, an unsupervised predictive model of learning achievement was constructed from variables identified using the principal component analysis technique on the responses. the instrument used is the modified test of understanding graphs-kinematics comprehension. students from two universities in Bogotá, Colombia participated. The results show a lower level of accuracy in students in remote face-to-face mode, compared to the reference group of physical presence; by way of reflection, the forced educational experiment implies resizing the teaching activity in the teaching and learning of movement.

Analysis of the dispersivity in soils by applying a modified test based on the pinhole method

The Pinhole test is an empirical probe with a qualitative classification foundation that identifies fine-grained soils with dispersive potential using hydraulic heads. However, the original technique was designed to identify dispersive clays. In some cases, it is misused as a quantitative test for measuring subsurface erosion rates. This paper presents a physicochemical modification to the exact test, based on adding a dispersant in the sample compaction water. For the quantitative evaluation of the susceptibility of the soil to generate internal tubification or piping, the effects of hydraulic load, flow, and orifice diameter before and after the execution of the test are explored—both for the samples treated with deflocculant and for those compacted using distilled water. Additionally, to complete the identification results, physical and chemical approaches were applied as methods of comparison. The results obtained from the altered soils indicate a significant increase in the clay fraction among the samples at the end of the test and gains of 3.7 and 6.2 times the initial diameter. The study demonstrates that the modified test is suitable for identifying non-dispersive soils before raising the percolation pressure. This modification is helpful for the improvement of the test because it helps to understand the procedure better and allows to calibrate the apparatus used.

Modification and validation of the test procedure for determination of sub-visible particulate matter in parenteral solutions, using the Coulter method

The State Pharmacopoeia of the Russian Federation, 14th edition provides for determination of sub-visible particles (less than 100 µm in size) in parenteral dosage forms using the Coulter method, in addition to the light obscuration particle count test and microscopy. However, the proposed 100 µm aperture tube does not enable assessment of the whole range of sub-visible particle sizes. Therefore, research is needed to find optimal test conditions for determination of sub-visible particulate matter by the Coulter method. The aim of the study: modification of the Coulter-based procedure using a 200 µm aperture tube, and performance of validation studies. Materials and methods: Multisizer 4e Coulter counter, suspensions of reference latex particles (10 µm, 20 µm, and 43 µm), and a particulate count reference standard containing 0.998 × 106 particles/mL were used in the study. The following parameters were assessed during validation: accuracy, repeatability, linearity. Results: the study confirmed the feasibility of using the modified Coulter-based procedure with a 200 µm aperture tube. The following values were obtained during validation of the modified test procedure: accuracy was 5.3% (deviation from the mean value) as compared to the particulate count reference standard, and 4.2% as compared to the light obscuration method. Repeatability was 1% (relative standard deviation) for the particle concentration of approximately 10000 per 1 mL, and 7.6% for the particle concentration of approximately 300 per 1 mL. The study demonstrated the linearity of the procedure, the linear correlation coefficient was more than 0.99. Conclusions: the studied validation parameters of the modified test procedure were shown to comply with the acceptance criteria. The modified test procedure will enable assessment of the whole range of sub-visible particle sizes when testing parenteral solutions for particulate contamination: sub-visible particles.

A Modified Two-Way Active Avoidance Test for Combined Contextual and Auditory Instrumental Conditioning

Available two-way active avoidance paradigms do not provide contextual testing, likely due to challenges in performing repetitive trials of context exposure. To incorporate contextual conditioning in the two-way shuttle box, we contextually modified one of the chambers of a standard two-chamber rat shuttle box with visual cues consisting of objects and black and white stripe patterns. During the 5 training days, electrical foot shocks were delivered every 10 s in the contextually modified chamber but were signaled by a tone in the plain chamber. Shuttling between chambers prevented an incoming foot shock (avoidance) or aborted an ongoing one (escape). During contextual retention testing, rats were allowed to freely roam in the box. During auditory retention testing, visual cues were removed, and tone-signaled shocks were delivered in both chambers. Avoidance gradually replaced escape or freezing behaviors reaching 80% on the last training day in both chambers. Rats spent twice more time in the plain chamber during contextual retention testing and had 90% avoidance rates during auditory retention testing. Our modified test successfully assesses both auditory and contextual two-way active avoidance. By efficiently expanding its array of outcomes, our novel test will complement standard two-way active avoidance in mechanistic studies and will improve its applications in translational research.

HOW TO AVOID THE ZERO-POWER TRAP IN TESTING FOR CORRELATION

In testing for correlation of the errors in regression models, the power of tests can be very low for strongly correlated errors. This counterintuitive phenomenon has become known as the “zero-power trap.” Despite a considerable amount of literature devoted to this problem, mainly focusing on its detection, a convincing solution has not yet been found. In this article, we first discuss theoretical results concerning the occurrence of the zero-power trap phenomenon. Then, we suggest and compare three ways to avoid it. Given an initial test that suffers from the zero-power trap, the method we recommend for practice leads to a modified test whose power converges to $1$ as the correlation gets very strong. Furthermore, the modified test has approximately the same power function as the initial test and thus approximately preserves all of its optimality properties. We also provide some numerical illustrations in the context of testing for network generated correlation.

Blowup results for the fractional Schrödinger equation without gauge invariance

<p style='text-indent:20px;'>This paper is concerned with the nonexistence of global solutions to the fractional Schrödinger equations with order <inline-formula><tex-math id="M1">\begin{document}$ \alpha $\end{document}</tex-math></inline-formula> and nongauge power type nonlinearity <inline-formula><tex-math id="M2">\begin{document}$ |u|^p $\end{document}</tex-math></inline-formula> for any space dimensions, where <inline-formula><tex-math id="M3">\begin{document}$ \alpha\in (0, 2] $\end{document}</tex-math></inline-formula> is assumed to be any fractional numbers. A modified test function is employed to overcome some difficulties caused by the fractional operator and to establish blowup results. Some restrictions with respect to <inline-formula><tex-math id="M4">\begin{document}$ \alpha, p $\end{document}</tex-math></inline-formula> and initial data in the previous literature are removed.</p>