Dimensional Synthesis of a Novel 3-URU Translational Manipulator Implemented through a Novel Method

A dimensional synthesis of parallel manipulators (PMs) consists of determining the values of the geometric parameters that affect the platform motion so that a useful workspace with assigned sizes can be suitably located in a free-from-singularity region of its operational space. The main goal of this preliminary dimensioning is to keep the PM far enough from singularities to avoid high internal loads in the links and guarantee a good positioning precision (i.e., for getting good kinematic performances). This paper presents a novel method for the dimensional synthesis of translational PMs (TPMs) and applies it to a TPM previously proposed by the author. The proposed method, which is based on Jacobians’ properties, exploits the fact that TPM parallel Jacobians are block diagonal matrices to overcome typical drawbacks of indices based on Jacobian properties. The proposed method can be also applied to all the lower-mobility PMs with block diagonal Jacobians that separate platform rotations from platform translations (e.g., parallel wrists).

Social Mobility and Horizontal Inequality

Research on social mobility has paid considerable attention to links with inequality. The vast majority of this work, however, has focused on ‘vertical’ inequality between individuals or households, rather than ‘horizontal’ inequality between groups in society. This chapter speaks to the latter, with focus on the persistence over time of horizontal inequalities between ethnic and culturally defined groups. Not only is such persistence due to low intergenerational mobility overall, we argue, it also is due to lower mobility for disadvantaged as compared with advantaged groups in many societies. Group-based discrimination, among other factors, contributes. We posit further that the relationship between low mobility and persistent horizontal inequality is a comparatively larger problem for Global South as compared to Global North countries, because they are, on average, contexts with lower intergenerational mobility, higher horizontal inequality, and weaker state capability and the rule of law.

Analysis of rotation capacity of a novel 2R1T mechanism based on origami of thick panels

A foldable and symmetrical lower-mobility parallel mechanism was proposed based on Waterbomb origami of thick panels. It consists of a moving platform, a base plate and three deployable foldable legs between moving platform and base plate. Firstly, constraint wrenches of each leg were formulated based on screw theory and the results illustrated that the moving platform is in possession of two degrees of orientation freedom and one translational degree of freedom. Secondly, it was approved that base and moving platform are always symmetrical about a middle plane and the moving platform can rotate continuously about any axis chosen freely on this plane. Solving models including forward and inverse position problems were established to determine the maximum rotational angle and workspace. Finally, performance indexe of maximum rotational angle of the PM was analyzed, and effects of two structural variables to the performance were summarized. Conclusions obtained can provide a theoretical basis for the structural design and engineering application of this 2T1R parallel mechanism.

Pulmonary Embolism in COVID-19 Patients: Facts and Figures

COVID-19 infection affects many systems in the body including the coagulation mechanisms. Imbalance between pro-coagulant and anticoagulant activities causes a roughly nine times higher risk for pulmonary embolism (PE) in COVID-19 patients. The reported incidence of PE in COVID-19 patients ranges from 3 to 26%. There is an increased risk of PE in hospitalized patients with lower mobility and patients requiring intensive care therapy. Obesity, atrial fibrillation, raised pro-inflammatory markers, and convalescent plasma therapy increases the risk of PE in COVID-19 patients. Endothelial injury in COVID-19 patients causes loss of vasodilatory, anti-adhesion and fibrinolytic properties. Viral penetration and load leads to the release of cytokines and von Willebrand factor, which induces thrombosis in small and medium vessels. D-dimers elevation gives strong suspicion of PE in COVID-19 patients, and normal D-dimer levels effectively rule it out. Point of care echocardiogram may show right heart dilatation, thrombus in heart or pulmonary arteries. DVT increases the risk of developing PE. The gold standard test for the diagnosis of PE is CTPA (computerized tomographic pulmonary angiography) which also gives alternative diagnosis in the absence of PE. Therapeutic anticoagulation is the corner stone in the management of PE and commonly used anticoagulants are LMWH (low molecular weight heparin) and UFH (unfractionated heparin). Mortality in COVID-19 patients with PE is up to 43% compared to COVID patients without PE being around 3%.

Evaluation of the ultradiluted medication MPD 30 CH in the offspring of mice mothers treated with methylphenidate during lactation.

Background: Methylphenidate (MPD) is a non-stimulating amphetamine that has being used for some time in the treatment of Attention Deficit Hyperactivity Disorder (ADHD) and, in adequate doses, it promotes the remission of symptoms and the improvement of important aspects, as social interaction and academic performance1, in patients with ADHD. Literature data indicates that MPD attenuates maternal behavior in mices2. According to this line of study, the work “Repeated methylphenidate administration during lactation reduces maternal behavior, induces maternal tolerance, and increases anxiety-like behavior in pups in adulthood”3 was carried out and confirmed that MPD administration during early lactation disrupts maternal behavior and causes anxiety in pups in adulthood. Would it be possible that ultradiluted and dynamized MPD change pups’ behavior? Objective: The aim of this study was to evaluate how the ultradiluted drug may or may not change the behavior of the animals at issue. Material and Methods: The medication was prepared according to the Brazilian Homeopathic Pharmacopeia, in the 30 CH dilution. The present study was approved by the Ethics Committee for Animal Experimentation of the Paulista University (No. 256/14 CEP / ICS / UNIP). Animals in this study were the same of the study above mentioned, and already published. Adult male mice were grouped among 13 animals of the experimental group (adults, offspring of mothers that received MPD during pregnancy) and 9 animals from the mother-control group, which did not take MPD during pregnancy. The 22 animals took ultradiluted MPD 30 CH medication in their drinking water ad libitum, for 20 days. In each water drinker, 5 drops of medication were added and stirred. Behavioral tests, such as the Open Field and the Light Dark Transition Test for mice, were performed. Data was analyzed statistically by the Student's T-Test to compare parametric data from two groups and the Mann-Whitney Test for nonparametric data, where p ≤ 0.05 is considered significant. Results and Discussion: In the Open Field Test, from the group of mothers medicated with methylphenidate during pregnancy, before the medication MPD 30 CH, animals showed a lower mobility and a greater immobility (p≤ 0.05) compared to the control-animals; after medication with the MPD 30 CH, animals exhibited an increase in mobility and a decrease in immobility, leading to no statistical difference between the medication group and the control group. In the Light Dark Transition Test for mice, experimental animals spent more time in the dark box and exhibited a decrease of the Rearing, presenting an anxious behavior; after the MPD medication, there were no more differences between experimental and control groups. Indiscriminate use of amphetamines has increased in recent years and this use, when not monitored, can cause serious adverse effects4. In this sense, ultradiluted medication can collaborate with the remission of possible undesirable effects. Conclusion: Initially, the MPD 30 CH changed the behavior shown by animals born from mothers that took methylphenidate during lactation and presented an anxious behavior as an unexpected effect. The mice that took the MPD 30 CH did not present the anxious behavior. Other experiments should be conducted to confirm the results of this study.

Mobility analysis of a robotic cardiopulmonary resuscitation device

During chest compressions action, in CPR (CPR), the 2 arms of the rescuer constitute a parallel mechanism. Inspired by this performance, during this study a specific family of lower mobility parallel manipulators by employing a modified version of Delta robot is proposed for chest compressions in rescuing a patient. One of the biggest differences between this mechanism and the Delta parallel mechanism is that the position of the three active connections of the robot relative to each other has changed the geometry of the platforms. Also, it shapes the asymmetrical structure within the robot mechanism and its workspace. Another difference is due to the architectural optimization method considering the mixed performance index, which has been used during this mechanism to achieve a much better compromise between the manipulator dexterity and its workspace. Within the present paper, after introducing the architecture of the robot, a closed-form solution is developed for the kinematic problem and therefore the results are verified using MSC. Adams©. Then Jacobian matrix is generated to gauge the singularity problem of the proposed mechanism. then, the workspace of the robot is investigated and compared with the original Delta mechanism.

Performance evaluation of mixed SCTP and TCP traffic over last hop wifi

The use of the internet has increased significantly with the continued increase in wireless communication devices. Recently, there is a large number of research contribution focused on Stream Control Transmission Protocol (SCTP). Multi-homing is an important feature of SCTP which improves the communication performance by usage of multiple paths during association establishment, and it can bring significant improvements of throughput. In this thesis we evaluate the performance of SCTP and TCP traffic in the WLANs and we investigate the SCTP multi-homing to improve the communication performance in WLANs. We conducted some experiments to evaluate the performance of SCTP multi-homed host under various channel bit rates and mobility speeds. The results indicate that when the intensity of background traffic increases the SCTP multi-homed host with higher channel bit rate has better performance. In addition, the SCTP multi-homed host with using lower mobility speed has higher performance (throughput, delay and packet loss).

Performance evaluation of mixed SCTP and TCP traffic over last hop wifi

The use of the internet has increased significantly with the continued increase in wireless communication devices. Recently, there is a large number of research contribution focused on Stream Control Transmission Protocol (SCTP). Multi-homing is an important feature of SCTP which improves the communication performance by usage of multiple paths during association establishment, and it can bring significant improvements of throughput. In this thesis we evaluate the performance of SCTP and TCP traffic in the WLANs and we investigate the SCTP multi-homing to improve the communication performance in WLANs. We conducted some experiments to evaluate the performance of SCTP multi-homed host under various channel bit rates and mobility speeds. The results indicate that when the intensity of background traffic increases the SCTP multi-homed host with higher channel bit rate has better performance. In addition, the SCTP multi-homed host with using lower mobility speed has higher performance (throughput, delay and packet loss).