Multi-axis control of telemanipulators

The development of multi-axis hand controllers for use in telemanipulator systems is described. Experience in the control of the SRMS (shuttle remote manipulator system) arm is reviewed together with subsequent tests involving a number of simulators and configurations, including use as a side-arm flight control for helicopters. The factors affecting operator acceptability are reviewed

Evolutionary economics and regional policy

The principal objective of this paper is to formulate some possible links between evolutionary economics and regional policy, a topic that has not (yet) been covered by the literature. We firstly give a brief overview of some issues of regional policy, conceived as a strategy to influence the spatial matrix of economic development. Then, we outline what we take to be the essential arguments and components of evolutionary economics. More in particular, we focus attention on the economic foundation of technology policy from an evolutionary perspective, and how this deviates from the so-called "equilibrium" rationale. Then, we examine in what way evolutionary insights may be helpful for regional policy matters. Our main emphasis is to investigate the degrees fo freedom policy makers may have to determine the future development of regions. When evolutionary mechanisms like chance and increasing returns are mainly involved in the spatial formation of new economic activities, there are several, but quite contradictory, options for policy makers. On the one hand, the importance of early chance events implies that multiple potential outcomes of location are quite thinkable. This is a principal problem for regional policy because new development paths can not be planned or even foreseen. On the other hand, policy makers may have a role to play here. Since space exercises only a minor influence on the location of new economic activities, there is room for policy makers to act and to build-up a favourable local environment. In this respect, urbanisation economies may offer advantages of flexibility secured by a diversity of activities which tends to prevent a process of negative lock-in. When evolutionary mechanisms like selection and path dependency are crucial for the geography of innovation, policy makers are expected to have more influence on the spatial pattern of innovation. In such circumstances, new variety is regarded as strongly embedded in its surrounding environment: the local environment acts as a sort of selection mechanism because it may, or may not, provide conditions favourable to meet the new requirements of new technology. Adaptation to change is largely constrained by the boundaries of the spatial matrix laid down in the past: only minor modifications tend to take place and do not undermine the logic of the spatial system.

Genetic analysis of immunological traits in tilapia

The immunological response to handling stress of four tilapia species is evaluated.Polymorphism is examined in genes known to influence immune response in fish

Bryophytes of Uganda : 1., BBS Tropical Bryology Group expeditions, 1996-1998 ; introduction and collecting sites

The British Bryological Society Tropical Bryology Group (TBG) undertook three expeditions to Uganda, in Jan-Feb 1996, Jan-Feb 1997 and June-Jul 1998. Collections were made from 134 sites, mainly from national parks and forest reserves in western and southern Uganda

Charge asymmetry in high-energy μ+μ−\mu^+\mu^- photoproduction in the electric field of a heavy atom

The charge asymmetry in the differential cross section of high-energy $\mu^+\mu^-$ photoproduction in the electric field of a heavy atom is obtained. This asymmetry arises due to the Coulomb corrections to the amplitude of the process (next-to-leading term with respect to the atomic field). The deviation of the nuclear electric field from the Coulomb field at small distances is crucially important for the charge asymmetry. Though the Coulomb corrections to the total cross section are negligibly small, the charge asymmetry is measurable for selected final states of $\mu^+$ and $\mu^-$. We further discuss the feasibility for experimental observation of this effect.Comment: 6 pages, 3 figure

Proton Electromagnetic Form Factor Ratios at Low Q^2

We study the ratio $R\equiv\mu G_E(Q^2)/G_M(Q^2)$ of the proton at very small values of $Q^2$. Radii commonly associated with these form factors are not moments of charge or magnetization densities. We show that the form factor $F_2$ is correctly interpretable as the two-dimensional Fourier transformation of a magnetization density. A relationship between the measurable ratio and moments of true charge and magnetization densities is derived. We find that existing measurements show that the magnetization density extends further than the charge density, in contrast with expectations based on the measured reduction of $R$ as $Q^2$ increases.Comment: 4 pages 3 figures We have corrected references, figures and some typographical error

Evaluation of Transplant Root Length on Bell Pepper Yield and Quality

Allowing bell pepper transplants to develop a taproot system was detrimental to early plant growth. However, it did not have a significant detrimental effect on most fruit yield and quality parameters measured, and by final harvest, plants of all three root length treatments had similar above ground plant weights

Placental-mediated increased cytokine response to lipopolysaccharides: a potential mechanism for enhanced inflammation susceptibility of the preterm fetus.

BackgroundCerebral palsy is a nonprogressive motor impairment syndrome that has no effective cure. The etiology of most cases of cerebral palsy remains unknown; however, recent epidemiologic data have demonstrated an association between fetal neurologic injury and infection/inflammation. Maternal infection/inflammation may be associated with the induction of placental cytokines that could result in increased fetal proinflammatory cytokine exposure, and development of neonatal neurologic injury. Therefore, we sought to explore the mechanism by which maternal infection may produce a placental inflammatory response. We specifically examined rat placental cytokine production and activation of the Toll-like receptor 4 (TLR4) pathway in response to lipopolysaccharide exposure at preterm and near-term gestational ages.MethodsPreterm (e16) or near-term (e20) placental explants from pregnant rats were treated with 0, 1, or 10 μg/mL lipopolysaccharide. Explant integrity was assessed by lactate dehydrogenase assay. Interleukin-6 and tumor necrosis alpha levels were determined using enzyme-linked immunosorbent assay kits. TLR4 and phosphorylated nuclear factor kappa light chain enhancer of activated B cells (NFκB) protein expression levels were determined by Western blot analysis.ResultsAt both e16 and e20, lactate dehydrogenase levels were unchanged by treatment with lipopolysaccharide. After exposure to lipopolysaccharide, the release of interleukin-6 and tumor necrosis alpha from e16 placental explants increased by 4-fold and 8-9-fold, respectively (P < 0.05 versus vehicle). Conversely, interleukin-6 release from e20 explants was not significantly different compared with vehicle, and tumor necrosis alpha release was only 2-fold higher (P < 0.05 versus vehicle) following exposure to lipopolysaccharide. Phosphorylated NFκB protein expression was significantly increased in the nuclear fraction from placental explants exposed to lipopolysaccharide at both e16 and e20, although TLR4 protein expression was unaffected.ConclusionLipopolysaccharide induces higher interleukin-6 and tumor necrosis alpha expression at e16 versus e20, suggesting that preterm placentas may have a greater placental cytokine response to lipopolysaccharide infection. Furthermore, increased phosphorylated NFκB indicates that placental cytokine induction may occur by activation of the TLR4 pathway