In the paper the positivity problem of the model of an one dimensional heat transfer process is addressed. Such a problem has not been considered yet. The considered thermal process is described by the fractional order state equation, derived from parabolic heat equation with homogenous Neumann boundary conditions and distributed control and observation. The internal and external positivity of the model depend on heater and sensor location as well as the size of the model. It is proved that the external positivity of the considered system can be achieved without internal positivity. Conditions of the internal and external positivity are proposed and proved. Theoretical considerations are supported by experiments. Experiments were done using the real system containing typical industrial components. The proposed results can be applied in real temperature measurements, for example in thermal cameras.This article addresses the problem of course keeping for unmanned surface vehicle (USV) subject to rudder servo characteristics, disturbances, uncertainties and rudder saturation. A double loop robust compound control strategy is developed by incorporating finite-time uncertainty observer (FUO) and auxiliary dynamic system into trajectory linearization control (TLC). TLC is an effective robust control technique with simple design structure, which is used in the course control experiment of USV for the first time. In each loop, the FUO and auxiliary system are designed to compensate unknown lumped disturbances and input saturation, respectively. A nonlinear tracking differentiator (NTD) is concurrently introduced to realize differentiation and filtering for the reference command. Strict stability analysis indicates that the entire system is uniformly ultimately bounded (UUB). Results from simulations and experiments are presented to validate the developed strategy.

Mandated social distancing has been applied globally to reduce the spread of coronavirus disease 2019 (COVID-19). However, the beneficial effects of this community-based intervention have not been proven or quantified for the COVID-19 pandemic.

This is a regional population-level observational study.

Using publicly available data, we examined the effect of timing of mandated social distancing on the rate of COVID-19 cases in 119 geographic regions, derived from 41 states within the United States and 78 other countries. The highest number of new COVID-19 cases per day recorded within a geographic unit was the primary outcome. find more The total number of COVID-19 cases in regions where case numbers had reached the tail end of the outbreak was an exploratory outcome.

We found that the highest number of new COVID-19 cases per day per million persons was significantly associated with the total number of COVID-19 cases per million persons on the day before mandated social distancing (β=0.66, P<0.0001). These findings suggest that if mandated social distancing is not initiated until the number of existing COVID-19 cases has doubled, the eventual peak would result in 58% more COVID-19 cases per day. Subgroup analysis on those regions where the highest number of new COVID-19 cases per day has peaked showed increase in β values to 0.85 (P<0.0001). The total number of cases during the outbreak in a region was strongly predicted by the total number of COVID-19 cases on the day before mandated social distancing (β=0.97, P<0.0001).

Initiating mandated social distancing when the numbers of COVID-19 cases are low within a region significantly reduces the number of new daily COVID-19 cases and perhaps also reduces the total number of cases in the region.

Initiating mandated social distancing when the numbers of COVID-19 cases are low within a region significantly reduces the number of new daily COVID-19 cases and perhaps also reduces the total number of cases in the region.The coronavirus disease pandemic and the growing movements for social and racial equality have increased awareness of disparities in American health care that exist on every level. Social determinants of health, structural racism, and implicit bias play major roles in preventing health equity. We begin with the larger picture and then focus on examples of systemic and health inequities and their solutions that have special relevance to allergy-immunology. We propose a 4-prong approach to address inequities that requires (1) racial and ethnic inclusivity in research with respect to both participants and investigators, (2) diversity in all aspects of training and practice, (3) improvement in communication between clinicians and patients, and (4) awareness of the social determinants of health. By communication we mean sensitivity to the role of language, cultural background, and health beliefs in physician-patient interactions and provision of training and equipment so that the use of telecommunication can be a resource for all patients. The social determinants of health are the social factors that affect health and the success of health care, such as adequacy of housing and access to nutritious foods. Using this 4-prong approach we can overcome health disparities.

Percutaneous sacroiliac screw is one of the main methods to treat unstable posterior pelvic ring injury. However, complexity of pelvic anatomical structure increases the difficulty and risk with freehand operation. Besides, S2 screw fixation began to receive attention. The purpose of the current study was to evaluate the safety, accuracy, efficiency and clinical outcome of robot-assisted S2 screw fixation for posterior pelvic ring injury.

We reviewed 128 cases of unstable posterior pelvic ring injury treated by percutaneous sacroiliac screw fixation in our hospital from January 2016 to January 2020. All cases were divided into robot-assisted S1 group (RAS1), robot-assisted S2 group (RAS2), freehand group S1 group (FHS1) and freehand group S2 group (FHS2). The mean times of fluoroscopy per screw and adjustment per guide wire were used to evaluate radiation exposure and the efficiency of screw placement, respectively. The final position of the screw was evaluated with postoperative CT to illustrate security and accuracy.