Phasic modulation of corticomotor excitability during passive movement of the upper limb: effects of movement frequency and muscle specificity

Modulations in the excitability of spinal reflex pathways during passive rhythmic movements of the lower limb have been demonstrated by a number of previous studies [4]. Less emphasis has been placed on the role of supraspinal pathways during passive movement, and on tasks involving the upper limb. In the present study, transcranial magnetic stimulation (TMS) was delivered to subjects while undergoing passive flexion-extension movements of the contralateral wrist. Motor evoked potentials (MEPs) of flexor carpi radialis (FCR) and abductor pollicus brevis (APB) muscles were recorded. Stimuli were delivered in eight phases of the movement cycle during three different frequencies of movement. Evidence of marked modulations in pathway excitability was found in the MEP amplitudes of the FCR muscle, with responses inhibited and facilitated from static values in the extension and flexion phases, respectively. The results indicated that at higher frequencies of movement there was greater modulation in pathway excitability. Paired-pulse TMS (sub-threshold conditioning) at short interstimulus intervals revealed modulations in the extent of inhibition in MEP amplitude at high movement frequencies. In the APE muscle, there was some evidence of phasic modulations of response amplitude, although the effects were less marked than those observed in FCR. It is speculated that these modulatory effects are mediated via Ia afferent pathways and arise as a consequence of the induced forearm muscle shortening and lengthening. Although the level at which this input influences the corticomotoneuronal pathway is difficult to discern, a contribution from cortical regions is suggested. (C) 2001 Published by Elsevier Science B.V.

No Easy Way Through: Black Workers and Race Leadership at the Nadir

It is difficult, even excruciating, to imagine the staggering descent from high optimism to despondency experienced by many African Americans who lived between emancipation and the dawn of the twentieth century. For historians living in the post–civil rights era, recapturing the scale, velocity, and brutality of that dramatic fall has been hampered by two conceptual problems. The first of these, undergirded by prominent trends in the formerly “new” social history, is a widely shared enthusiasm for illuminating those hidden corners of daily life where men and women on the receiving end of Jim Crow continued to wield a degree of control. “Agency” has been the buzzword for a generation of scholarship that emphasizes the staying power and persistence of black Southerners in the face of relentless assaults on their social and economic status, their civil rights, and even, at times, their collective existence. This is, in many ways, an understandable reaction to an earlier consensus that relegated black historical initiative to the margins of a national fable cleansed of unseemly violence and sharp social conflict, but it can also be problematic.

Any Nearer to Victory in the Fifty Years War?:Assessing the European Commission’s Leadership, Weapons and Strategies towards combating Cartels

Some 50 years after its creation EU competition policy remains firmly entrenched as one of the most developed examples of supranational governance within the European Union. Although there has been a marked increase in interest among political scientists in competition policy in recent years there are still gaps in terms of overall coverage. One area that has been largely overlooked centres on cartels. Cartel policy has emerged as a highly salient issue and main priority of the Commission's competition policy since the late 1990s. Certainly, the recent restructuring of the EU cartel enforcement regime, the imposition of ever higher fines and a determined EU Competition Commissioner have fuelled growing media attention while new notices and regulations increasingly occupy the interests and minds of practitioners. The European Commission has constantly extended its activities on the competition policy front and its increasingly aggressive strategies to combat cartels provides political scientists with a fascinating case study of governance in action and illustrates the ways – such as leniency programmes, higher fines, enhanced and better equipped resources as well as internal reorganisation in which the European regulator is pursuing such conspiracies. This article traces the evolution and development of EU cartel policy since its inception and assesses the Commission's strategies and considers just to what extent the European Commission is winning its war against business cartelisation.

Habitat for Humanity: Calibrating Best Practice Against the MDGs

Poverty alleviation lies at the heart of contemporary international initiatives on development. The key to development is the creation of an environment in which people can develop their potential, leading productive, creative lives in accordance with their needs, interests and faith. This entails, on the one hand, protecting the vulnerable from things that threaten their survival, such as inadequate nutrition, disease, conflict, natural disasters and the impact of climate change, thereby enhancing the poor’s capabilities to develop resilience in difficult conditions. On the other hand, it also requires a means of empowering the poor to act on their own behalf, as individuals and communities, to secure access to resources and the basic necessities of life such as water, food, shelter, sanitation, health and education. ‘Development’, from this perspective, seeks to address the sources of human insecurity, working towards ‘freedom from want, freedom from fear’ in ways that empower the vulnerable as agents of development (not passive recipients of benefaction).

Recognition of the magnitude of the problems confronted by the poor and failure of past interventions to tackle basic issues of human security led the United Nations (UN) in September 2000 to set out a range of ambitious, but clearly defined, development goals to be achieved by 2015. These are known as the Millennium Development Goals (MDGs). The intention of the UN was to mobilise multilateral international organisations, non-governmental organisations and the wider international community to focus attention on fulfilling earlier promises to combat global poverty. This international framework for development prioritises: the eradication of extreme poverty and hunger; achieving universal primary education; promoting gender equality and empowering women; reducing child mortality; improving maternal health; combating HIV/AIDS, malaria and other diseases; ensuring environmental sustainability; and developing a global partnership for development. These goals have been mapped onto specific targets (18 in total) against which outcomes of associated development initiatives can be measured and the international community held to account. If the world achieves the MDGs, more than 500 million people will be lifted out of poverty. However, the challenges the goals represent are formidable. Interim reports on the initiative indicate a need to scale-up efforts and accelerate progress.
Only MDG 7, Target 11 explicitly identifies shelter as a priority, identifying the need to secure ‘by 2020 a significant improvement in the lives of at least 100 million slum dwellers’. This raises a question over how Habitat for Humanity’s commitment to tackling poverty housing fits within this broader international framework designed to allievate global poverty. From an analysis of HFH case studies, this report argues that the processes by which Habitat for Humanity tackles poverty housing directly engages with the agenda set by the MDGs. This should not be regarded as a beneficial by-product of the delivery of decent, affordable shelter, but rather understood in terms of the ways in which Habitat for Humanity has translated its mission and values into a participatory model that empowers individuals and communities to address the interdependencies between inadequate shelter and other sources of human insecurity. What housing can deliver is as important as what housing itself is.

Examples of the ways in which Habitat for Humanity projects engage with the MDG framework include the incorporation of sustainable livelihoods strategies, up-grading of basic infrastructure and promotion of models of good governance. This includes housing projects that have also offered training to young people in skills used in the construction industry, microfinanced loans for women to start up their own home-based businesses, and the provision of food gardens. These play an important role in lifting families out of poverty and ensuring the sustainability of HFH projects. Studies of the impact of improved shelter and security of livelihood upon family life and the welfare of children evidence higher rates of participation in education, more time dedicated to study and greater individual achievement. Habitat for Humanity projects also typically incorporate measures to up-grade the provision of basic sanitation facilities and supplies of safe, potable drinking water. These measures not only directly help reduce mortality rates (e.g. diarrheal diseases account for around 2 million deaths annually in children under 5), but also, when delivered through HFH project-related ‘community funds’, empower the poor to mobilise community resources, develop local leadership capacities and even secure de facto security of tenure from government authorities.

In the process of translating its mission and values into practical measures, HFH has developed a range of innovative practices that deliver much more than housing alone. The organisation’s participatory model enables both direct beneficiaries and the wider community to tackle the insecurities they face, unlocking latent skills and enterprise, building sustainable livelihood capabilities. HFH plays an important role as a catalyst for change, delivering through the vehicle of housing the means to address the primary causes of poverty itself. Its contribution to wider development priorities deserves better recognition. In calibrating the success of HFH projects in terms of units completed or renovated alone, the significance of the process by which HFH realises these outcomes is often not sufficiently acknowledged, both within the organisation and externally. As the case studies developed in the report illustrate, the methodologies Habitat for Humanity employs to address the issue of poverty housing within the developing world, place the organisation at the centre of a global strategic agenda to address the root causes of poverty through community empowerment and the transformation of structures of governance.

Given this, the global network of HFH affiliates constitutes a unique organisational framework to faciliate sharing resources, ideas and practical experience across a diverse range of cultural, political and institutional environments. This said, it is apparent that work needs to be done to better to faciliate the pooling of experience and lessons learnt from across its affiliates. Much is to be gained from learning from less successful projects, sharing innovative practices, identifying strategic partnerships with donors, other NGOs and CBOs, and engaging with the international development community on how housing fits within a broader agenda to alleviate poverty and promote good governance.

Effects of Geometrical Discontinuities on Distributed Passive Intermodulation in Printed Lines

This paper presents the results of experimental study of passive intermodulation (PIM) generation in microstrip lines with U-shaped and meandered strips, impedance tapers, and strips with the profiled edges. It is shown that the geometrical discontinuities in printed circuits may have a noticeable impact on distributed PIM generation even when their effect is indiscernible in the linear regime measurements. A consistent interpretation of the observed phenomena has been proposed on the basis of the phase synchronism in the four-wave mixing process. The results of this study reveal new features of PIM production important for the design and characterization of low-PIM microstrip circuits. © 2010 IEEE.