Undesirable Position Research Articles

Migrant agricultural workers in search of a dignified life: Labour conditions as a source of vulnerability in Spain

AbstractThis study analyses the dynamics of agency and social vulnerability of international migrant agricultural workers in intensive agriculture in Murcia (South‐East Spain). It engages with the work of a group of scholars who analysed the emergence and reproduction of Murcia as an intensive agricultural enclave by taking an expanded vision of social reproduction, which includes a subjective and contextual dimension in the definition of what constitutes a ‘dignified life’. Based on a qualitative study of the life stories of foreign migrant agricultural workers and ex‐workers in Murcia, two main arguments are developed. Firstly, the idea of migrant workers’ agency as intrinsically positive is evaluated as problematic. Secondly, agricultural labour conditions should be conceptualized as an independent social vulnerability driver. These findings contribute to the existing literature on migrant agricultural labour in Europe's intensive agriculture by pointing at migrants’ exploitative and undesired labour market position rather than just at their suffered citizenship inequalities.

The Dilemma of Ahistorical Teleosemantics

AbstractTeleosemantic theories aim to naturalize mental representation through the use of functions, typically based on past selection processes. However, the historical dependence of these theories has faced severe criticism, leading some philosophers to develop ahistorical alternatives. This article presents a new dilemma for all ahistorical teleosemantic theories, focusing in particular on the theories proposed by Timothy Schroeder and Bence Nanay. These theories require certain dispositions in the producers or consumers of mental representations, but the appeal to dispositions puts the proponents in an undesirable position: mental content is either overly dependent on current circumstances or ultimately dependent on historical factors.

Women's health nurses' experiences of menopause: Considerations for nurse leaders.

Women's health nurses' experiences of menopause: Considerations for nurse leaders.

Development and Experimental Studies of a Method Based on a Reference Control Signal Generating System for Redundant Serial Manipulators

The paper presents the design and experimental study of a synthesis method based on reference signal generation systems. The method can be used for all actuators of redundant manipulators. The aforementioned systems aim to save the dynamic control accuracy of the working tools of serial manipulators when they move along arbitrary spatial trajectories, taking into account restrictions in all degrees of freedom and special cases of their link positions. The maintenance of the control accuracy could be ensured by eliminating the reach of all degrees of freedom of manipulators to their limits and to indicated special positions, characterized by an ambiguity when solving the inverse kinematic problems of various serial manipulators. This is in addition to preventing the reach of their working tools to the boundaries of the working area due to the use of a redundant degree of freedom when approaching the indicated undesirable positions. The experimental studies performed in this paper confirm the efficiency of the proposed method and allow accurate characteristics to be obtained.

Does Intra-operativeFluoroscopy Significantly Improve Component Position in a Primary Total Hip Arthroplasty? Our Experience in a Tertiary Care Hospital.

Optimal component placement, equalization of leg lengths, and recreation of offset are important surgical objectives during total hip arthroplasty (THA). Historically, many surgeons have aimed for the Lewinnek's " safe zone," which is defined as 30°-50° of abduction and 5°-25° of anteversion. Methods for optimizing cup position include anatomic landmarks, room landmarks, acetabular cup coverage, and ischial or pubis palpation. Malposition of the acetabular component after total hip arthroplasty (THA) is related to dislocation of the prosthetic femoral head, increased polyethylene liner wear, and limited range of motion. The orientation of the acetabular component comprises inclination and anteversion. Although the inclination of the acetabular component can be easily measured on plain radiographs, the calculation of the anteversion is difficult. This study evaluates the effect of intra-operative fluoroscopy on component position, mainly anteversion and inclination of the acetabular cup, during a total hip arthroplasty. 106 hips undergoing total hip arthroplasty were assessed, and the decision to use fluoroscopy assistance was randomized based on a simple randomization technique. A total of 48 patients were operated on with fluoroscopy assistance and 58 patients without fluoroscopy assistance. All patients were evaluated postoperatively for version of component on anteroposterior radiographs of the hip using the method of Liaw et al. and for inclination of component on anteroposterior radiographs using the method of Woo and Morrey. The mean version for the non-fluoroscopy (NF) group was 15.62° and the mean inclination was 44.22°, with 15.5% (9 out of 58) of the patients who did not fit into Lewinnek's safe zone for version and 25.9% (15 out of 58) of the patients who were outliers for inclination of the acetabular cup position. The mean version for the fluoroscopy group (F) was 11.80° and the mean inclination was 47.05°, with 0% (0 out of 48) of the patients who did not fit into Lewinnek's safe zone for version and 12.5% (6 out of 48) of the patients who were outliers for inclination of the acetabular cup position. While the mean version and inclination of the acetabular component were comparable for both groups, outliers for version and inclination were far more common in the group of patients who underwent surgery without intra-operative fluoroscopic assistance. Therefore, intra-operative fluoroscopy imaging confirms appropriate inclination (abduction) and version of acetabular cup position according to Lewinnek's safe zone and prevents undesirable component position during a total hip arthroplasty while adding a maximum of 5min to the operative time.

Manipulation at optimum locations for maximum force transmission with mobile robots under environmental disturbances

Remote manipulation plays a key role for applications in hazardous conditions, yet designing a robust controller enabling safe interaction with unknown environment and under the influence of disturbances is a challenge. In this study, we propose effective control and optimization methods for mobile robotic manipulator systems that can increase effort transmission to a task in desired directions. The vehicle position is optimized by utilizing constrained particle swarm optimization where the objective is to enhance directional manipulability of the robotic arm within the system. A forward dynamic controller is implemented to eliminate undesired excessive motions near singular joint configurations. A reset control algorithm along with an admittance type controller are developed for stable interaction with an unknown object under environmental disturbances. The experimentally validated results show that the proposed method phase out undesired position disturbances and increase the directional manipulability for the required task enabling augmented effort transmission for the task execution.

파라미터 중복성을 제거한 로봇 매니퓰레이터의 위치 기반 기구학 캘리브레이션

Industrial robot manipulators require high absolute position accuracy of the end effector to perform precise and complex tasks. However, manufacturing errors cause differences between nominal and actual parameters, and errors between the expected and actual positions of the end effector, resulting in undesired lower absolute position accuracy. Accordingly, to increase the absolute position accuracy of the end effector, kinematic calibration is required to correct the nominal parameters close to the actual parameters. However, in this study, redundancy of parameters may occur from the overlapping degrees of freedom of parameters in adjacent frames, which causes the problem of unnecessarily correcting many parameters in the optimization process. Thus, to solve this problem and use only the necessary parameters, this paper focuses on the linear relationship of redundant parameters and proposes a method of automatically discriminating and removing it through the Pearson Correlation Analysis. Additionally, through simulations on the two manipulator models, we verify the accuracy of redundancy of parameters determined by the proposed method, and demonstrate consistency and efficiency by comparing the results before and after redundancy removal.

ПРИМЕНЕНИЕ ИНТЕРФЕЙСА PYTHON-ADAMS ДЛЯ МОДЕЛИРОВАНИЯ РАБОТЫ ПЛАТФОРМЫ ГЬЮ-СТЮАРТА

The article presents a technique for modeling the operation of the parallel structure mechanism - the Hugh-Stewart robotic platform using a virtual prototype. The MSC Adams software package and the high-level general-purpose object-oriented programming language Python were used as modeling tools. The digital layout, which has the properties of a parameterized simulation model, is built in the MSC Adams software package. The Python programming language is used as an alternative to the Adams View internal command language for creating and iteratively modifying modeling objects in Adams. The proposed implementation of the Python-Adams interface in the form of special procedures and functions automates the execution of a computational experiment and allows solving the problem of optimizing structural elements and finding the optimal geometric design of the hexapod in accordance with the selected optimality criteria by conducting a series of experiments consisting in sequential multiple changes in geometric parameters, followed by simulation model and analysis of the results in order to find design options that meet the specified criteria. The technique was tested on the example of optimizing the diameter of the platform according to the criterion of minimizing the effort expended when moving along a given trajectory. The results of a computational experiment are also presented to determine the dynamic parameters (forces, moments of forces) in the structural elements when the platform moves along a complex trajectory, to identify undesirable positions in which peak loads occur.

Polar Chromosomes-Challenges of a Risky Path.

The process of chromosome congression and alignment is at the core of mitotic fidelity. In this review, we discuss distinct spatial routes that the chromosomes take to align during prometaphase, which are characterized by distinct biomolecular requirements. Peripheral polar chromosomes are an intriguing case as their alignment depends on the activity of kinetochore motors, polar ejection forces, and a transition from lateral to end-on attachments to microtubules, all of which can result in the delayed alignment of these chromosomes. Due to their undesirable position close to and often behind the spindle pole, these chromosomes may be particularly prone to the formation of erroneous kinetochore-microtubule interactions, such as merotelic attachments. To prevent such errors, the cell employs intricate mechanisms to preposition the spindle poles with respect to chromosomes, ensure the formation of end-on attachments in restricted spindle regions, repair faulty attachments by error correction mechanisms, and delay segregation by the spindle assembly checkpoint. Despite this protective machinery, there are several ways in which polar chromosomes can fail in alignment, mis-segregate, and lead to aneuploidy. In agreement with this, polar chromosomes are present in certain tumors and may even be involved in the process of tumorigenesis.

Position‐sensitivity security transmission with orbital angular momentum directional modulation based on frequency diverse array

AbstractThe position‐sensitivity security communication scheme with orbital angular momentum (OAM) directional modulation (DM) beam pattern generated by the uniform circular frequency diverse array (FDA) is proposed. The transmitter employs FDA antennas to generate dual‐mode range‐dependent OAM beam and the direction information of OAM beam is modulated into the signal. The designed signal with random frequency offset excites the element of the uniform circular FDA to generate orthogonal OAM signals in the desired position. In the undesired position, the intensity pattern and the phase front of the radio beam vary randomly with the digital sequence transmission, which can make eavesdropping difficult. Since the modulation waveform has position‐dependent, the signal can be purposely distorted in undesired positions to provide transmission security for the legitimate user. The composite dual‐mode OAM signal makes it more difficult for eavesdroppers to demodulate correct messages. The receiver with a single antenna employs the phase compensation and helical phase factor to restore the correct digital signal in the desired position. Numerical results show that the space position‐sensitivity OAM‐DM technology based on FDA offers a security transmission scheme.

COVID-19 response in Colombia: Hits and misses

IntroductionColombia has been hit particularly hard by the COVID-19 pandemic, being ranked 22nd among 187 countries in deaths per 100,000 people by February 2022. The country has also experienced the worst economic recession in its history, with real GDP contracting 7% in 2020. This paper describes Colombia's pre-pandemic context and the overall effect of the pandemic on health and economic indicators and examines the government's response to COVID-19. MethodsDescriptive chronologic policy analysis on the COVID-19 pandemic in Colombia and the measures and interventions implemented, using publicly available secondary data from Colombia's official agencies and international sources published from March 2020 to February 2022. ResultsThe Colombian healthcare system increased its capacity in terms of infrastructure and human resources (from 8.6 ICU beds per 100,000 pre-pandemic to 21.9 in 2020, from 1.7 to 1.3 per 1000 doctors and nurses, respectively in 2019 to 1.8 and 1.5 per 1000 in 2020). The government commenced the National Vaccination Strategy on February 17, 2021, despite a slow start it managed to fully vaccinate 65.1% of its population, including Venezuelan immigrants, by February 2022. ConclusionsColombia's response to the pandemic combines hits and misses. The country organized an early and robust response; increased its healthcare system capacity; designed a risk-based, equitable, and inclusive national vaccination strategy; and introduced a flexible and responsive vaccine rollout. However, the government chose the wrong timing for reform, implemented a long and unpredictable lockdown, was late to procure COVID-19 vaccines and has not appropriately tackled vaccine hesitancy. Public interest summaryColombia has been hit particularly hard by the COVID-19 pandemic, with over 138,000 COVID-19 deaths and over 6 million cases by the end of February 2022. According to number of deaths per 100,000 people, Colombia ranks 22nd in the world, among 187 countries. The country has also experienced the worst economic recession in its history. The Colombian healthcare system has been able to cope with a high number of COVID-19 cases without collapsing, but some public health indicators deteriorated. Colombia's response to the pandemic combines hits and misses. The country organized an early and robust response; increased its healthcare system capacity; designed a risk-based, equitable, and inclusive national vaccination strategy; and introduced a flexible and responsive vaccine rollout. As of February 2022, Colombia has fully vaccinated 65.1% of its population. However, the government chose the wrong timing for a tax reform, implemented a long and unpredictable lockdown, was late to procure COVID-19 vaccines and has not appropriately tackled vaccine hesitancy, which certainly contributed to its undesirable position in the mortality world raking.

Development of the Method of Formation the Reference Signals for Electric Actuators of Manipulators with Redundant Degrees of Freedom. Part I

The solution of task of maintaining the dynamic accuracy of control of working tools of multilink manipulators (MM) when they move along arbitrary spatial trajectories is presented in this paper. In this case, constructive restrictions in all degrees of freedom (DoF) of manipulators and special cases of location of their links are taken into account. These special (singular) positions are characterized by ambiguity in solving inverse kinematics problem of these MM. Maintaining of control accuracy is proposed to be ensured by excluding the enter of all DoFs of manipulators to the restrictions, as well as excluding the enter of their working tools to the boundaries of the working area. This is accomplished by using a redundant DoF when approaching these undesirable positions. In the first part of the article, the features of the new solution of the inverse kinematics problem are considered and singular positions for 6-DoF manipulators with PUMA kinematic schemes are described. The presented solution of the inverse kinematics problem takes into account various combinations of genera- lized coordinates of the MM, which ensure the movement of their working tools to the specified positions with the required spatial orientation. This solution has low computational complexity compared to other known methods. This allows the use of low-power microprocessor computers to control the MM. The results of the performed mathematical simulation confirmed the high efficiency of using the proposed approach to the contour control of the MM.

Data-driven statistical analysis for discharge position prediction on Wire EDM

Wire-cut Electrical Discharge Machining (Wire EDM) is a machining technique widely used to cut high-precision punch tools and highly value added precision components. With increasing resource efficiency requirements and zero-defect manufacturing trend, pushing the limits of machining reliability, even at cutting speed next to the technical limits, is becoming imperative. Predicting the position of the sparks along the wire is thus needed to develop more efficient EDM processes, thanks to the suppression of discharges which are expected to happen in undesired positions. This will lead to a reduction of the number of machine stops caused by wire breaks. Motivated by this need, the paper presents a data-driven statistical analysis to get insight into the correlation between the discharge positions of two consecutive sparks, along with the relation between spark positions and discharge frequency. The underlying basis for this analysis was the possibility to obtain reliable real-time information about the position of sparks along the wire, a feature made available by a Discharge Location Tracker [4]. Results on spark position correlation are presented for cutting experiments on a steel workpiece of 50 mm in plane parallel with different machining parameters using brass wire of diameter 0.25 mm.

Tethering Complex Proteins and Protein Complexes for Optical Tweezers Experiments.

Tethering proteins to force probes, typically micrometer-sized beads, is a prerequisite for dissecting their properties with optical tweezers. DNA handles serve as spacers between the tethered protein of interest and the bead surface. Attachment sites of the DNA handles to both the surface of beads and to the protein of interest must be mechanically stable for optical tweezers experiments. The most prominent method for attaching DNA handles to proteins utilizes thiol chemistry, linking modified DNA to engineered cysteines in the target protein. This method, although experimentally straightforward, is impractical for the large number of proteins that endogenously contain multiple or essential cysteines at undesired positions. Here, we describe two alternative approaches that take advantage of genetically encoded tag sequences in the target protein. The first method uses the enzymes Sfp and BirA, and the second uses the more recently described SpyTag-SpyCatcher system. We outline the process of generating the DNA handles themselves, as well as how to make the DNA-protein chimeras for carrying out optical tweezers experiments. These methods have robustly worked for several diverse and complex proteins, including ones that are difficult to produce or purify, and for protein-containing complexes such as the ribosome. They will be useful in cases where chemistry-based approaches are impractical or not feasible.

Multitarget Position-Sensitivity Security Transmission with OAM-DM Based on FDA

The multitarget position-sensitivity security transmission scheme with orbital angular momentum (OAM) directional modulation (DM) waveform using the uniform circular frequency diverse array (FDA) is proposed. The transmitter employs FDA to generate dual-mode range-dependent OAM beam pattern, and the direction information of OAM beam is modulated into the signal. According to the modulation method, orthogonal carrier frequency can be designed to realize multitarget position-dependent OAM pattern. In the undesired position, the intensity pattern and the phase front of the radio beam vary randomly with the digital transmission sequence. Because modulation waveform is position-dependent, the technique offers security, as the signal can be purposely distorted in other positions. The composite dual-mode OAM signal makes it more difficult for eavesdroppers to demodulate correct messages. The receiver with a single antenna employs the phase compensation and helical phase factor to restore the correct digital signal in the desired position. Numerical results show that multitarget position-sensitivity OAM-DM technology based on FDA offers the security transmission scheme.

Method of Formation of Reference Control Signals for Redundant Manipulators

The paper is devoted to preservation of dynamic control accuracy of working tools of multilink manipulators when they move along arbitrary spatial trajectories, taking into account the design limits in all degrees of freedom and special cases of position of their links. Preservation of control accuracy is proposed to be ensured by eliminating reach of all degrees of freedom of the manipulators to the limits and to indicated special positions, characterized by ambiguity in solving the inverse kinematic problems of the manipulators, as well as excluding the reach of their working tools to boundaries of working area due to use of a redundant degree of freedom when approaching indicated undesirable positions. The performed simulation has confirmed efficiency of the proposed method.

COMPUTED TOMOGRAPHY-GUIDED COMMISSURAL ALIGNMENT OF THE EVOLUT VALVE USING THE CUSP-OVERLAP TECHNIQUE, A RETROSPECTIVE PILOT STUDY

<h3>BACKGROUND</h3> Advancement of transcatheter aortic valve replacement (TAVR) and its long-term outcomes is warranted as it expands to a low-risk population. Procedural optimization using commissural alignment (CA) and the cusp-overlap technique have recently been suggested, especially for supra-annular self-expanding valves. The Evolut valve (EV) has two markers to guide valve position and orientation: the hat-marker and the flush port. Although the EV platform orientation with the flush port to the 3 o'clock position seems to improve the likelihood of CA, commissural malalignment (CMA) remains an issue in a significant number of patients. <h3>METHODS AND RESULTS</h3> To improve CA, starting October 2020, we implemented a systematic, simplified workflow for all patients receiving the EV. The workflow uses CT-guided fluoroscopic angles to determine the hat-marker position during cusp-overlap view. To determine if the CT-guided individualized positioning workflow of the EV improves CA, we retrospectively reviewed all patients with the EV implanted at our center. The study included only patients with native aortic valve stenosis, transfemoral access and the use of the cusp-overlap technique. From September 2019 to March 2021, a total of 52 patients were enrolled in the study. The Hat position during cusp overlap deployment angle was classified as Outer Curve (OC), Center Front (CF), Inner Curve (IC), and Center Back (CB). Overall, CF hat marker position was achieved in 25 (48%) patients. For this analysis, we combined CB and IC in one group (CBIC). CF position has optimal alignment in 23/25 (92%) patients, while CBIC position was associated with 6/13 (46%) of severe CMA. Severe commissural overlap with coronary orifices occurred more frequently in the CBIC position than the CF position (LAD 53.8% vs 4%, and RCA 53.8% vs 0%). The implementation of our workflow decreased the undesirable CBIC position from 41.4% to 4.3% (P=0.001). There was a significant decrease in Severe CMA (20.7% to 0% p=0.023), and proper alignment (< 30 degrees) was achieved in 95% of patients after the implementation of the workflow. <h3>CONCLUSION</h3> This study showed that the Hat-marker position during cusp-overlap fluoroscopic view predicts CA, with the CF position being the best for optimal CA. Besides, this study showed that a systematic and simplified CT-guided workflow could potentially improve CA and minimize severe coronary orifice overlap with the neo-commissures.

Inoculation theory in the post‐truth era: Extant findings and new frontiers for contested science, misinformation, and conspiracy theories

AbstractAlthough there has been unprecedented attention to inoculation theory in recent years, the potential of this research has yet to be reached. Inoculation theory explains how immunity to counter‐attitudinal messages is conferred by preemptively exposing people to weakened doses of challenging information. The theory has been applied in a number of contexts (e.g., politics, health) in its 50+ year history. Importantly, one of the newest contexts for inoculation theory is work in the area of contested science, misinformation, and conspiracy theories. Recent research has revealed that when a desirable position on a scientific issue (e.g., climate change) exists, conventional preemptive (prophylactic) inoculation can help to protect it from misinformation, and that even when people have undesirable positions, “therapeutic” inoculation messages can have positive effects. We call for further research to explain and predict the efficacy of inoculation theory in this new context to help inform better public understandings of issues such as climate change, genetically modified organisms, vaccine hesitancy, and other contested science beliefs such as conspiracy theories about COVID‐19.

Theorising the neurotypical gaze: autistic love and relationships in The Bridge (Bron/Broen 2011–2018)

In popular media, autistic subjectivity is most often produced through the lens of the neurotypical gaze. Dominant understandings of autism therefore tend to focus on perceived deficits in social communication...

A Completely Endovascular Solution for Transcatheter Aortic Valve Implantation Embolisation and Inversion into the Aortic Arch

IntroductionTranscatheter aortic valve implantation (TAVI) has evolved into the preferred alternative to surgical valve replacement for severe aortic valve stenosis with high surgical risk. With expanding indications, life threatening complications including transcatheter aortic valve embolisation and inversion (TAVEI), in which the valve dislodges, inverts, and migrates caudally, may increase concomitantly.ReportAn 80 year old male with severe aortic valve stenosis underwent balloon expandable transcatheter aortic valve implantation (TAVI). Valve embolisation into the aortic arch inverted the bioprothesis, excluding the option of fixation in the descending aorta. Through-valve thoracic endovascular aortic repair (TEVAR) was performed after bifemoral snaring using a through-and-through wire technique and pulling the valve into the descending aorta.DiscussionTAVI is emerging as the preferred treatment for severe aortic valve stenosis and comes with unique procedural complications, such as life threatening transcatheter aortic valve embolisation and inversion (TAVEI). Although some authors prefer treating embolisation of a non-inverted balloon expandable valve into the aorta by using the valvuloplasty balloon to pull the valve distally and fixing it in the descending aorta, this risks further expansion of the valve and consequently fixing it in an undesirable position and is not possible if the valve inverts. Downstream placement of the valve by snaring with a guiding catheter covering/protecting a through-and-through wire technique, combined with through-valve TEVAR, provides a new bail out strategy for this serious complication and may reduce TAVEI associated mortality and morbidity.