The aim of this study was to determine the extent of ankle muscle weakness in children with cerebral palsy (CP) and to identify potential causes. Maximal voluntary contractions of plantar (PF) and dorsiflexors (DF) were determined at optimal angles in knee flexion and extension in both legs of 14 children with hemiplegia (7 males, 7 females) and 14 with diplegia (8 males, 6 females). Their results were compared to 14 age- and weight-matched control participants (5 males, 9 females). Muscle cross-sectional areas of soleus, posterior, and anterior compartment muscles were determined from MRIs in 14 children with CP (eight diplegia, six hemiplegia) and 18 control children. Specific tension (torque/unit area) of PF and DF was determined from torque and cross-sectional area results. Muscle volumes of PF and DF were also determined in both legs of five control children and five with hemiplegia. Muscle EMG was recorded from soleus, medial gastrocnemius, and tibialis anterior during each maximal voluntary contraction. Mean amplitude was significantly reduced in PF and DF in both CP groups and significantly higher levels of coactivation of antagonists were found compared to control participants. Strength of PF and DF was significantly reduced in both CP groups, but more importantly the muscles were found to be weak based on significantly reduced specific tensions. The PF were most affected, particularly in the group with hemiplegia. It is believed that an inability to maximally activate their muscles contributed to this weakness. A combination of incomplete activation and high levels of PF coactivation are thought to have contributed to DF weakness.

S Sc co op pe e a an nd d S Su ur rv vi iv va al l: : A A C Co om mp pa ar ri is so on n o of f C Co oo op pe er ra at ti iv ve e a an nd d C Ca ap pi it ta al li is st t M Mo od de es s o of f P Pr ro od du uc ct ti io on n" " N Na at tá ál li ia a P Pi im me en nt ta a M Mo on nt te ei ir ro o G Ge eo of ff f S St te ew wa ar rt t NIPE WP 08/ 2013 " "S Sc ca al le e, , S Sc co op pe e a an nd d S Su ur rv vi iv va al l: : A A C Co om mp pa ar ri is so on n o of f C Co oo op pe er ra at ti iv ve e a an nd d C Ca ap pi it ta al li is st t M Mo od de es s o of f P Pr ro od du uc ct ti io on n" " N Na at tá ál li ia a P Pi im me en nt ta a M Mo on nt te ei ir ro o G Ge eo of ff f S St te ew wa ar rt t Abstract This paper draws on a comprehensive data set from Portugal to investigate the activities, internal characteristics and survival prospects of cooperatives and capitalist enterprises. Consistent with theory, high levels of market concentration and low entrycosts were shown to be conducive to cooperatives. Cooperatives were found to be, on average, older and to operate with a larger, more highly educated and more productive labour forces than their capitalist counterparts. Finally, we show that cooperatives have a markedly higher probability of survival than capitalist enterprises, even after controlling for industry and …rm characteristics. JEL Classi…cation: J54, P12 1 1 See, for example, Baker and Hubbard (2004) on the impact of computers on the ownership of assets in the trucking industry, Hart and Moore (1996) on changes in the ownership of securities exchanges and Morrison and Wilhelm (2008) on the demise of partnerships in investment banking. 2 Whilst we are not aware of a formal theoretical model linking cooperative activity to levels of interpersonal trust, Jones and Kalmi (2009) cite a number of papers that provide arguments suggesting the existence of such a link. 3 Recent comparative studies involving worker cooperatives include Arando et al. (2012), Pérotin (2006) and Podivinsky and Stewart (2012).

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Local amenities play an important role in determining where we choose to live and our overall quality of life. In many cases, however, amenities do not have prices and will therefore be underprovided by the market. In this paper, we use individual and county level data for England and Wales to estimate implicit amenity prices and to calculate an index of quality of life for each county. Among our …ndings is a large negative price on air pollution. The range in quality of life across counties is estimated to be in excess of two thousand pounds per year. JEL Classification: I31, R1Keywords: Quality of Life index, amenities, hedonic prices.