Fault-tolerant formation driving mechanism designed for heterogeneous MAVs-UGVs groups

A fault-tolerant method for stabilization and navigation of 3D heterogeneous formations is proposed in this paper. The presented Model Predictive Control (MPC) based approach enables to deploy compact formations of closely cooperating autonomous aerial and ground robots in surveillance scenarios without the necessity of a precise external localization. Instead, the proposed method relies on a top-view visual relative localization provided by the micro aerial vehicles flying above the ground robots and on a simple yet stable visual based navigation using images from an onboard monocular camera. The MPC based schema together with a fault detection and recovery mechanism provide a robust solution applicable in complex environments with static and dynamic obstacles. The core of the proposed leader-follower based formation driving method consists in a representation of the entire 3D formation as a convex hull projected along a desired path that has to be followed by the group. Such an approach provides non-collision solution and respects requirements of the direct visibility between the team members. The uninterrupted visibility is crucial for the employed top-view localization and therefore for the stabilization of the group. The proposed formation driving method and the fault recovery mechanisms are verified by simulations and hardware experiments presented in the paper

Preliminary Limits on the WIMP-Nucleon Cross Section from the Cryogenic Dark Matter Search (CDMS)

We are conducting an experiment to search for WIMPs, or weakly-interacting massive particles, in the galactic halo using terrestrial detectors. This generic class of hypothetical particles, whose properties are similar to those predicted by extensions of the standard model of particle physics, could comprise the cold component of non-baryonic dark matter. We describe our experiment, which is based on cooled germanium and silicon detectors in a shielded low-background cryostat. The detectors achieve a high degree of background rejection through the simultaneous measurement of the energy in phonons and ionization. Using exposures on the order of one kilogram-day from initial runs of our experiment, we have achieved (preliminary) upper limits on the WIMP-nucleon cross section that are comparable to much longer runs of other experiments.Comment: 5 LaTex pages, 5 eps figs, epsf.sty, espcrc2dsa2.sty. Proceedings of TAUP97, Gran Sasso, Italy, 7-11 Sep 1997, Nucl. Phys. Suppl., A. Bottino, A. di Credico and P. Monacelli (eds.). See also http://cfpa.berkeley.ed

Familial tumoral calcinosis in two Chinese patients: a case series

Abstract Introduction Tumoral calcinosis is a rare and benign condition characterized by massive subcutaneous soft tissue deposits of calcium phosphate predominantly around large joints. Case presentation Familial tumoral calcinosis was present in two members of a Han Chinese family, namely, the son and daughter. The 14-year-old son had the first operation on his right sole of the foot at the age of six, and then experienced subsequent surgeries at a lesion in his right sole of the foot and left hip, respectively. The 16-year-old daughter underwent her first operation at the age of six in her left gluteal region, and subsequent surgeries were performed due to recurrence at the same lesion. Pathologic diagnoses of surgical specimens in both of the patients were reported as tumoral calcinosis. The laboratory results showed hyperphosphatemia with normal levels of serum calcium and alkaline phosphatase. Only surgical treatment was performed in both patients with satisfactory prognosis. Conclusion This is the first report of Chinese familial tumoral calcinosis. The etiopathogenisis and treatment are discussed.</p

Fast, scalable, Bayesian spike identification for multi-electrode arrays

We present an algorithm to identify individual neural spikes observed on high-density multi-electrode arrays (MEAs). Our method can distinguish large numbers of distinct neural units, even when spikes overlap, and accounts for intrinsic variability of spikes from each unit. As MEAs grow larger, it is important to find spike-identification methods that are scalable, that is, the computational cost of spike fitting should scale well with the number of units observed. Our algorithm accomplishes this goal, and is fast, because it exploits the spatial locality of each unit and the basic biophysics of extracellular signal propagation. Human intervention is minimized and streamlined via a graphical interface. We illustrate our method on data from a mammalian retina preparation and document its performance on simulated data consisting of spikes added to experimentally measured background noise. The algorithm is highly accurate

UK experience of liver transplantation for erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is characterised by excess production of free protoporphyrin from the bone marrow, most commonly due to deficiency of the enzyme ferrochelatase. Excess protoporphyrin gives rise to the cutaneous photosensitivity characteristic of the disease, and in a minority of patients leads to end-stage liver disease necessitating liver transplantation (LT). There is limited information regarding the timing, impact and long-term outcome of LT in such patients, thus we aimed to identify the indications and outcomes of all transplants performed for EPP in the UK using data from the UK Transplant Registry. Between 1987 and 2009, five patients underwent LT for EPP liver disease. Median follow-up was 60 months, and there were two deaths at 44 and 95 months from causes unrelated to liver disease. The remaining recipients are alive at 22.4 years, 61 months and 55 months after transplant. A high rate of postoperative biliary stricturing requiring multiple biliary interventions was observed. Recurrent EPP-liver disease occurred in 4/5 (80%) of patients but graft failure has not been observed. Given the role of biliary obstruction in inducing EPP-mediated liver damage, we suggest that consideration should be given for construction of a Roux loop at the time of transplant. Thus we demonstrate that although EPP liver transplant recipients have a good long-term survival, comparable to patients undergoing LT for other indications, biliary complications and disease recurrence are almost universal, and bone marrow transplantation should be considered where possible

Intra-articular vs. systemic administration of etanercept in antigen-induced arthritis in the temporomandibular joint. Part II: mandibular growth

<p>Abstract</p> <p>Background</p> <p>Temporomandibular joint (TMJ) arthritis in children causes alterations in the craniomandibular growth. Resultant abnormalities include; condylar erosions, a posterior mandibular rotation pattern, micrognathia, malocclusion with an anterior open bite, altered joint and muscular function occasionally associated with pain. These alterations may be prevented by early aggressive anti-inflammatory intervention. Previously, we have shown that intra-articular (IA) corticosteroid reduces TMJ inflammation but causes additional mandibular growth inhibition in young rabbits. Local blockage of TNF-α may be an alternative treatment approach against TMJ involvement in juvenile idiopathic arthritis (JIA). We evaluated the anti-inflammatory effect of IA etanercept compared to subcutaneous etanercept in antigen-induced TMJ-arthritis in young rabbits in terms of mandibular growth. This article (Part II) presents the data and discussion on the effects on facial growth. In Part I the anti-inflammatory effects of systemic and IA etanercept administration are discussed.</p> <p>Methods</p> <p>Arthritis was induced and maintained in the TMJs of 10-week old pre-sensitized rabbits (n = 42) by four repeated IA TMJ injections with ovalbumin, over a 12-week period. One group was treated weekly with systemic etanercept (0.8 mg/kg) (n = 14), another group (n = 14) received IA etanercept (0.1 mg/kg) bilaterally one week after induction of arthritis and one group (n = 14) served as an untreated arthritis group receiving IA TMJ saline injections. Head computerized tomographic scans were done before arthritis was induced and at the end of the study. Three small tantalum implants were inserted into the mandible, serving as stable landmarks for the super-impositions. Nineteen variables were evaluated in a mandibular growth analysis for inter-group differences. All data was evaluated blindedly. ANOVA and T-tests were applied for statistical evaluation using p < 0.05 as significance level.</p> <p>Results</p> <p>Significant larger mandibular growth disturbances were observed in the group receiving IA saline injections compared with the systemic etanercept group. The most pronounced unfavourable posterior mandibular rotation pattern was observed in the group receiving IA saline injections.</p> <p>Conclusion</p> <p>Intervention with systemic etanercept monotherapy equivalent to the recommended human dose allows a mandibular growth towards an original morphology in experimental TMJ arthritis. Systemic administrations of etanercept are superior to IA TMJ administration of etanercept in maintaining mandibular vertical growth.</p

Where form and substance meet: using the narrative approach of re-storying to generate research findings and community rapprochement in (university) mathematics education

Storytelling is an engaging way through which lived experience can be shared and reflected upon, and a tool through which difference, diversity—and even conflict—can be acknowledged and elaborated upon. Narrative approaches to research bring the richness and vibrancy of storytelling into how data is collected and interpretations of it shared. In this paper, I demonstrate the potency of the narrative approach of re-storying for a certain type of university mathematics education research (non-deficit, non-prescriptive, context-specific, example-centred and mathematically focused) conducted at the interface of two communities: mathematics education and mathematics. I do so through reference to Amongst Mathematicians (Nardi, 2008), a study carried out in collaboration with 20 university mathematicians from six UK mathematics departments. The study deployed re-storying to present data and analyses in the form of a dialogue between two fictional, yet entirely data-grounded, characters—M, mathematician, and RME, researcher in mathematics education. In the dialogues, the typically conflicting epistemologies—and mutual perceptions of such epistemologies—of the two communities come to the fore as do the feasibility-of, benefits-from, obstacles-in and conditions-for collaboration between these communities. First, I outline the use of narrative approaches in mathematics education research. Then, I introduce the study and its use of re-storying, illustrating this with an example: the construction of a dialogue from interview data in which the participating mathematicians discuss the potentialities and pitfalls of visualisation in university mathematics teaching. I conclude by outlining re-storying as a vehicle for community rapprochement achieved through generating and sharing research findings—the substance of research—in forms that reflect the fundamental principles and aims that underpin this research. My conclusions resonate with sociocultural constructs that view mathematics teacher education as contemporary praxis and the aforementioned inter-community discussion as taking place within a third space

Intra-articular vs. systemic administration of etanercept in antigen-induced arthritis in the temporomandibular joint. Part II: mandibular growth

<p>Abstract</p> <p>Background</p> <p>Temporomandibular joint (TMJ) arthritis in children causes alterations in the craniomandibular growth. Resultant abnormalities include; condylar erosions, a posterior mandibular rotation pattern, micrognathia, malocclusion with an anterior open bite, altered joint and muscular function occasionally associated with pain. These alterations may be prevented by early aggressive anti-inflammatory intervention. Previously, we have shown that intra-articular (IA) corticosteroid reduces TMJ inflammation but causes additional mandibular growth inhibition in young rabbits. Local blockage of TNF-α may be an alternative treatment approach against TMJ involvement in juvenile idiopathic arthritis (JIA). We evaluated the anti-inflammatory effect of IA etanercept compared to subcutaneous etanercept in antigen-induced TMJ-arthritis in young rabbits in terms of mandibular growth. This article (Part II) presents the data and discussion on the effects on facial growth. In Part I the anti-inflammatory effects of systemic and IA etanercept administration are discussed.</p> <p>Methods</p> <p>Arthritis was induced and maintained in the TMJs of 10-week old pre-sensitized rabbits (n = 42) by four repeated IA TMJ injections with ovalbumin, over a 12-week period. One group was treated weekly with systemic etanercept (0.8 mg/kg) (n = 14), another group (n = 14) received IA etanercept (0.1 mg/kg) bilaterally one week after induction of arthritis and one group (n = 14) served as an untreated arthritis group receiving IA TMJ saline injections. Head computerized tomographic scans were done before arthritis was induced and at the end of the study. Three small tantalum implants were inserted into the mandible, serving as stable landmarks for the super-impositions. Nineteen variables were evaluated in a mandibular growth analysis for inter-group differences. All data was evaluated blindedly. ANOVA and T-tests were applied for statistical evaluation using p < 0.05 as significance level.</p> <p>Results</p> <p>Significant larger mandibular growth disturbances were observed in the group receiving IA saline injections compared with the systemic etanercept group. The most pronounced unfavourable posterior mandibular rotation pattern was observed in the group receiving IA saline injections.</p> <p>Conclusion</p> <p>Intervention with systemic etanercept monotherapy equivalent to the recommended human dose allows a mandibular growth towards an original morphology in experimental TMJ arthritis. Systemic administrations of etanercept are superior to IA TMJ administration of etanercept in maintaining mandibular vertical growth.</p