Adaptive thrust vector control during on-orbit servicing

On-orbit servicing missions often include a final propulsive phase where a spacecraft pushes the other one towards a different orbit. Specifically this is the case of the debris grasping mission where the chaser, after capturing the target by means of robotic arms, has to perform a de-orbit operation. The large thrust involved needs a perfect alignment with respect to the center of mass or the system composed by chaser and target, in order to avoid attitude changes. Such accurate alignment is quite difficult to achieve especially when the characteristics of the target are not perfectly known. A procedure is proposed in this paper, allowing a complete estimation of the center of mass position and of the moments of inertia of the system, starting from the data obtained by the gyros mounted on board of the spacecraft. The output is used to design a maneuver for correcting the target and chaser relative position by moving the robotic arms. Numerical simulations show the proficiency and the applicability of the estimation algorithm and of re-alignment maneuver to a selected mission scenario

Anosognosia and self-correction of naming errors in aphasia

Background: There has been comparatively little research into anosognosia for aphasia (a lack of awareness of acquired language deficits). Direct assessments of metacognitive awareness tend to rely on high levels of verbal competence and are difficult for people with aphasia to complete. Therefore indirect measures of awareness have been considered, notably the person’s self-correction of his or her naming errors. Different mechanisms for self-correction based in comprehension or production skills have been proposed. In addition, in other areas of cognition, the relationships between direct and indirect measures and underlying forms of awareness have not been clearly established. Aims: The aims of this study were: a) to investigate the relationship between a direct and an indirect measure of awareness of aphasia, b) to examine the role of executive functioning in performance on both assessment types, and c) to examine the relationship between these measures and underlying language comprehension and production skills. Methods & Procedures: Forty-eight people with aphasia participated, drawn from rehabilitation hospital caseloads. Participants were assessed on a language battery, a non-verbal test of executive function, a direct measure of awareness (ratings of difficulties), and had self-correction behaviour examined in a 40-item naming test. Outcomes & Results: There was a trend relationship between performance on the direct and indirect measures. Both related to overall severity of language impairment, with more severely impaired people being less aware of their difficulties. The two measures, however, dissociated with respect to single-word production and comprehension scores: the direct measure related to production and not comprehension, while the indirect measure related to comprehension and not production. Executive functioning related only to the direct measure of metacognitive awareness. Within production scores, the rate of correction success rather than pre-correction naming rate was associated with metacognitive awareness. Conclusions: This study revealed different underlying bases, in language processes and executive function, for two measures of anosognosia for aphasia. When used to assess awareness of deficits, direct and indirect methods should not be regarded as equivalent

Physical interactions in swarm robotics: the hand-bot case study

This paper presents a case-study on the performance achieved by the mechanical interactions of self-assembling mobile robots. This study is based on the hand-bot robot, designed to operate within heterogeneous swarms of robots. The hand-bot is specialized in object manipulation and can improve its performance by exploiting physical collaborations by self-assembling with other hand-bots or with foot-bots (ground robots). The paper analyzes the achieved performance and demonstrates the highly super-linear properties of the accessible volume in respect to the number of robots. These extremely interesting performances are strongly linked to the self-assembling mechanisms and the physical nature of the interaction, and do not scale to a large number of robots. Finally, this study suggests that such interesting properties are more accessible for heterogeneous systems or devices achieving complex tasks

Demonstration of a Hybrid Space Architecture During RIMPAC 2020

The Micro-Satellite Military Utility (MSMU) Project Arrangement (PA) is an agreement under the Responsive Space Capabilities (RSC) Memorandum of Understanding (MOU) that involves the Departments and Ministries of Defence of Australia, Canada, Germany, Italy, the Netherlands, New Zealand, Norway, United Kingdom and United States. MSMU’s charter is to inform a space enterprise that provides military users with reliable access to a broad spectrum of information in an opportunistic environment. Research and Development teams from MSMU partner nations supported Exercise Rim of the Pacific (RIMPAC) 2020 which took place 17 to 31 August 2020 in the Hawaiian region. RIMPAC 2020 provided an opportunity to explore the military utility of a Hybrid Space Architecture (HSA) of satellites including traditional government and commercial satellites, as well as micro-satellites and nanosatellites, by leveraging contributions across the MSMU partner nations. The objective was to continue testing the hypothesis that an HSA, mostly composed of small satellites, can bring significant value to the operational theatre. The MSMU PA partner nations have leveraged several multi-national exercises, with the first being the Exercise RIMPAC 2018. Previous exercises enabled multinational technology advancements, interoperability testing, process refinement, and capability developments to make advancements towards MSMU’s goal to address the warfighter’s need for diverse ISR capabilities. The most recent accomplishment was a major integration effort across mission planning tools, space-based Intelligence, Surveillance and Reconnaissance (ISR) data providers, and exploitation tools. The MSMU team accessed ~256 space-based sensors (EO – Electro Optical, SAR – Synthetic Aperture Radar, AIS – Automatic Identification System) to collect maritime domain and ISR data over a harbor, airfields and open sea. Data was exploited via international channels in order to determine the success rate of capturing pertinent data to be later exploited and disseminated. This paper describes results from the experiment and offers insights into the HSA military utility

Produção de memórias falsas com listas de associados : análise do efeito do nível de processamento e da natureza da prova de memória

As memórias falsas têm sido amplamente estudadas com base num procedimento experimental designado paradigma DRM (Deese/Roediger/McDermott). Esse paradigma promove a criação de ilusões de memória a partir da apresentação de listas de palavras associadas a um item que não consta da lista. Uma das linhas de investigação com o paradigma DRM visa identificar o momento da criação das falsas memórias e explicar os mecanismos que estão na sua origem. Neste artigo, pretendemos fazer uma revisão da investigação sobre o efeito do nível de processamento e da natureza da tarefa de memória na facilitação ou inibição da produção de memórias falsas com listas de associados semânticos.False memories have been widely studied using an experimental procedure called DRM paradigm (Deese/Roediger/McDermott). This paradigm produces memory illusions due to the presentation of lists of words associated to a critical nonpresented word. One line of research on this topic aims at identifying the moment when the false memories are created and the explanation of the mechanisms underling false memories. In this paper we present a review about the effect of level-of-processing and the nature of memory task for the boost or inhibition of false memories created by means of lists of semantic associates.Le paradigme DRM (Deese/Roediger/McDermott) est un des plus connus et plus robustes parmi les études des faux mémoires dans le contexte du laboratoire. Ce paradigme permet la création d illusions de mémoire à partir des mots sémantiquement associés à un item qui n a pas été présenté. Au milieu des investigations basées sur le paradigme DRM il y a des études dont l objectif est d identifier e d´expliquer les mécanismes qui sont à l origine de la production des faux mémoires. Plus spécifiquement, on a pour but de faire une révision de la recherche sur l effet du niveau de codification et de la nature des tâches de mémoire sur la facilitation ou l´inhibition de la production de faux mémoires à partir des mots sémantiquement associés.Los falsos recuerdos han sido muy estudiados mediante la aplicación del paradigma DRM (Deese/Roediger/McDermott). El paradigma permite producir ilusiones de memoria tras la presentación de listas de palabras asociadas a una palabra que no se incluye en la lista. Una de las líneas de investigación que utilizan el paradigma DRM busca identificar el preciso momento de la creación de falsos recuerdos y explicar los mecanismos que originan ese efecto. El objetivo de este artículo es hacer una revisión de la investigación sobre el efecto de los niveles de procesamiento y la naturaleza de la tarea de memoria en la facilitación y inhibición de la producción de falsos recuerdos con listas de asociados semánticos.Fundação para a Ciência e a Tecnologia (FCT)Centro de Investigação em Psicologia da Universidade do Minho (CIPsi

The Mini-Mental State Examination (MMSE) as a diagnostic and screening test for delirium: Systematic review and meta-analysis

Objective: To analyse the evidence concerning the accuracy of the Mini-Mental State Examination (MMSE) as a diagnostic and screening test for the presence of delirium in adults. Method: Two authors searched MEDLINE, PsychINFO and EMBASE from inception till 3/2014. Articles were included that investigated the diagnostic validity of the MMSE to detect delirium against standardised criteria. A diagnostic validity meta-analysis was conducted. Results: Thirteen studies were included representing 2017 patients in medical settings of whom 29.4% had delirium. The meta-analysis revealed the MMSE had an overall sensitivity and specificity estimate of 84.1% and 73.0%, but this was 81.1% and 82.8% in a subgroup analysis involving robust high quality studies. Sensitivity was unchanged but specificity was 68.4% (95% CI = 50.9% to 83.5%) in studies using a predefined cut-off of < 24 to signify a case. In high-risk samples where delirium was present in 25% of patients, then the Positive predictive value and Negative predictive value would be 50.9% (48.3% - 66.2%) and 93.2% (90.0% - 96.5%). Conclusion: The MMSE cannot be recommended as a case-finding confirmatory test of delirium, but may be used as an initial screen to rule out high scorers who are unlikely to have delirium with approximately 93% accuracy

The WOMAN Trial (World Maternal Antifibrinolytic Trial): tranexamic acid for the treatment of postpartum haemorrhage: an international randomised, double blind placebo controlled trial

<p>Abstract</p> <p>Background</p> <p>Each year, worldwide about 530,000 women die from causes related to pregnancy and childbirth. Of the deaths 99% are in low and middle income countries. Obstetric haemorrhage is the leading cause of maternal mortality, most occurring in the postpartum period. Systemic antifibrinolytic agents are widely used in surgery to prevent clot breakdown (fibrinolysis) in order to reduce surgical blood loss. At present there is little reliable evidence from randomised trials on the effectiveness of tranexamic acid in the treatment of postpartum haemorrhage.</p> <p>Methods</p> <p>The Trial aims to determine the effect of early administration of tranexamic acid on mortality, hysterectomy and other morbidities (surgical interventions, blood transfusion, risk of non-fatal vascular events) in women with clinically diagnosed postpartum haemorrhage. The use of health services and safety, especially thromboembolic effect, on breastfed babies will also be assessed. The trial will be a large, pragmatic, randomised, double blind, placebo controlled trial among 15,000 women with a clinical diagnosis of postpartum haemorrhage. All legally adult women with clinically diagnosed postpartum haemorrhage following vaginal delivery of a baby or caesarean section will potentially be eligible. The fundamental eligibility criterion is the responsible clinician's 'uncertainty' as to whether or not to use an antifibrinolytic agent in a particular woman with postpartum haemorrhage. Treatment will entail a dose of tranexamic acid (1 gram by intravenous injection) or placebo (sodium chloride 0.9%) will be given as soon as possible after randomisation. A second dose may be given if after 30 minutes bleeding continues, or if it stops and restarts within 24 hours after the first dose.</p> <p>The main analyses will be on an 'intention to treat' basis, irrespective of whether the allocated treatment was received or not. Subgroup analyses for the primary outcome will be based on type of delivery; administration or not of prophylactic uterotonics; and on whether the clinical decision to consider trial entry was based primarily on estimated blood loss alone or on haemodynamic instability. A study with 15,000 women will have over 90% power to detect a 25% reduction from 4% to 3% in the primary endpoint of mortality or hysterectomy.</p> <p>Trial registration</p> <p>Current Controlled Trials: ISRCTN76912190 and Clinicaltrials.gov ID: NCT00872469</p