2,876 research outputs found

    Dynamic Path Planning and Replanning for Mobile Robots using RRT*

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    It is necessary for a mobile robot to be able to efficiently plan a path from its starting, or current, location to a desired goal location. This is a trivial task when the environment is static. However, the operational environment of the robot is rarely static, and it often has many moving obstacles. The robot may encounter one, or many, of these unknown and unpredictable moving obstacles. The robot will need to decide how to proceed when one of these obstacles is obstructing it's path. A method of dynamic replanning using RRT* is presented. The robot will modify it's current plan when an unknown random moving obstacle obstructs the path. Various experimental results show the effectiveness of the proposed method

    The effect of an intervention to improve newly qualified teachers’ interpersonal style, students motivation and psychological need satisfaction in sport-based physical education

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    Recent developments in self-determination theory research in the educational setting (e.g., Reeve, Deci, & Ryan, 2004), suggest that teachers’ interpersonal style should be considered as consisting of three dimensions: autonomy-support, structure and interpersonal involvement. Based on this theoretical proposition, the purpose of the present study was to test the effects of a training program for three physical education newly qualified teachers on the aforementioned teachers’ overt behaviors and students’ psychological needs satisfaction, self-determined motivation and engagement in sport-based physical education. After a baseline period of four lessons, the teachers attended an informational session on adaptive student motivation and how to support it. The training program also included individualized guidance during the last four lessons of the cycle. Results revealed that from pre- to post-intervention: (1) teachers managed to improve their teaching style in terms of all three dimensions, and (2) students were receptive to these changes, as shown by increases in their reported need satisfaction, self-determined motivation and engagement in the class

    Separating the anti-apoptotic and mitotic roles of survivin

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    Survivin is a bifunctional protein that acts as a suppressor of apoptosis and has an essential role in mitosis. To date whether these two functions can be divorced has not been addressed. Here we show that the linker region between the BIR (baculovirus inhibitor of apoptosis repeat) domain of survivin and COOH-terminal alpha helix may be the key to separating its roles. When overexpressed survivin is present in interphase cells and shuttles between the cytoplasm and nucleus. Here we identify a rev-like nuclear exportation signal (NES) in the central domain of survivin and demonstrate that point mutations within this region cause accumulation of survivin in the nucleus. Interestingly cells expressing NES mutants exhibit reduced survival after X-irradiation. Moreover, cells expressing survivin(L98A)-green fluorescent protein (GFP) showed increased poly(ADP-ribose) polymerase-cleavage and caspase-3 activity after tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment compared with cells expressing full-length survivin-green fluorescent protein. These data suggest a direct link between the interphase localization of survivin and cellular responsiveness to apoptotic stimuli. Using a cell proliferation assay, we also found that ectopic expression of NES mutants can complement for depletion of endogenous survivin, indicating that they can execute the mitotic duties of survivin. Thus we demonstrate for the first time that 1) survivin has a functional NES; 2) nuclear accumulation of overexpressed survivin correlates with increased sensitivity of cells to ionising radiation; and 3) the anti-apoptotic and mitotic roles of survivin can be separated through mutation of its NES. Separating these two functions of survivin could open up new possibilities for therapeutic strategies aimed at eliminating cancer cells yet preserving normal cell viability

    Living biointerfaces based on non-pathogenic bacteria to direct cell differentiation

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    Genetically modified Lactococcus lactis, non-pathogenic bacteria expressing the FNIII7-10 fibronectin fragment as a protein membrane have been used to create a living biointerface between synthetic materials and mammalian cells. This FNIII7-10 fragment comprises the RGD and PHSRN sequences of fibronectin to bind α5β1 integrins and triggers signalling for cell adhesion, spreading and differentiation. We used L. lactis strain to colonize material surfaces and produce stable biofilms presenting the FNIII7-10 fragment readily available to cells. Biofilm density is easily tunable and remains stable for several days. Murine C2C12 myoblasts seeded over mature biofilms undergo bipolar alignment and form differentiated myotubes, a process triggered by the FNIII7-10 fragment. This biointerface based on living bacteria can be further modified to express any desired biochemical signal, establishing a new paradigm in biomaterial surface functionalisation for biomedical applications

    Challenges and Opportunities to Scale Up Cardiovascular Disease Secondary Prevention in Latin America and the Caribbean.

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    In the Americas, CVD represents about 38% of noncommunicable disease deaths. A roadmap for secondary prevention in Latin America and the Caribbean is warranted. Simple and practical guidelines should be developed and implemented. PAHO proposes a realistic and efficient prevention coalition plan in Latin America to fight CVD. The inclusion of the health system through health workers is highly recommended for a successful nationwide preventive program

    Recovery of thicket in a revegetated limestone mine

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    The opencast extraction of limestone at the PPC Cement (Pty) Ltd Loerie quarry in the Eastern Cape, South Africa, has led to disturbance of the immediate environment. Large tracts of thicket have been removed during mining and exhausted quarry areas had to be revegetated. Revegetation commenced 16 years ago and as a result of progressive revegetation efforts since then, five seral stages were available for study. This presented an opportunity to describe the successional progression that occurs where thicket topsoil was used for revegetation. The quarry lies near the Gamtoos fault and both thicket and mountain fynbos is found in proximity to the mine. Before mining, the area was covered by thicket and quarry floors were revegetated by covering landscaped areas with thicket topsoil. The vegetation that developed in the quarry had a very low floristic relationship to fynbos. After 16 years, the vegetation also had a low similarity to thicket, even though the soils used for revegetation contained thicket propagules. The oldest seral stage (16years) was a Rhus incisa-Panicum deustum thicket in which only 46% of the species were mature thicket species. In order to develop thicket more rapidly, active intervention will be required. This could take the form of planting of saplings of key thicket species. A trial planting of such saplings showed high survival success of most species. Long-term (50year) monitoring will be required to determine whether this approach was successful

    Games People Play: The Collapse of “Masculinities” and the Rise of Masculinity as Spectacle

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    Perspective is important. When Andy Warhol produced an art piece of 13 police mugshots of “Thirteen Most Wanted Men” for the New York World’s Fair in 1964, the work was hurriedly painted over by concerned authorities before the public could view it. It was only years later that the Warhol’s subversive (homoerotic) gaze on the FBI list was more widely appreciated (Crimp in Social Text 59: 49–66, 1999; Siegel in Art Journal 62(1): 7–13, 2003). I begin with this story because it points to key issues I want to take up in this chapter, in particular, the importance of “audience” and different readings when it comes to masculinity. While current theory tends to locate masculinity in the actors, what if it is better located in the audience? What if masculinity was better understood as a kind of public spectacle? In addition, there are the naturally subversive elements of gender (e.g. think of drag performances); the game-like nature of masculinity (men might feel compelled to play along with expectations of masculinity—think of brutal playground expectations on boys—but it doesn’t mean they are not aware of its inauthenticity); and the inevitable—but less discussed link—with sexuality (see below)

    Challenging or reshaping heteronormativity with public policies? A case study from Bogotá, Colombia

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    On 28 December 2007 the then Mayor of Bogotá signed a Decree which established the guidelines of the public policy for the full guarantee of the rights of lesbian, gay, bisexual and transgender (LGBT) people in the city. This legal measure was the end point of a long lobbying and advocacy strategy implemented by activists and organisations working on gender and sexual diversity. This Working Paper presents that experience as part of the process in which subordinated social sectors, such as gender diverse and sexually diverse people make themselves political subjects. In spite of the novelty in Colombia and in Latin America of this kind of public policy targeting LGBT people as subjects of rights, it is also an opportunity for normative systems to readjust and to create new ways to normalise people. The promotion of certain queer people as proper citizens, the regulation of ways to interact with the state, the co-option of social mobilisations and the transformation of grassroots organisations into private service providers, are just some of the risks that a scheme like this faces. The author was part of the social mobilisation that motivated this particular public policy scheme in the early 2000s and was involved in its design, planning and initial implementation between 2007 and 2010. This paper is situated in a problematic position between political activism, consultancy work and construction of knowledge based on the practice. It is a contribution to the memory of a rich, and in many ways unique, experience
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