Countervailing power? Collusion in markets with decentralized trade

We consider the collective incentives of buyers and sellers to form cartels in markets where trade is realized through decentralized pairwise bargaining. Cartels are coalitions of buyers or sellers that limit market participation and compensate inactive members for abstaining from trade. In a stable market outcome, cartels set Nash equilibrium quantities and cartel memberships are immune to defections. We prove that the set of stable market outcomes is non-empty and we provide its full characterization. Stable market outcomes are of two types: (i) at least one cartel actively restrains trade and the levels of market participation are balanced, or (ii) only one cartel, eventually the cartel that forms on the long side of the market, is active and it reduces trade slightly below the opponent's.

Poder compensatório e política de defesa da concorrência: referencial geral e aplicação ao mercado de saúde suplementar brasileiro

A criação de poder compensatório decorrente da ação concertada daqueles prejudicados em uma relação de poder assimétrica pode gerar aumento de bem-estar social. O desenvolvimento analítico a partir da estrutura proposta por Dobson et al. (1998) permite constatar que as condições para que sejam verificados os efeitos positivos são restritivas e estão diretamente relacionadas ao reconhecimento da interdependência e à cooperação entre os agentes envolvidos. Foi possível observar também que, diferentemente do que previu a análise de Dobson et al. (1998), a criação de poder compensatório pode ter efeitos positivos em termos de bem-estar, ainda que as partes não reconheçam sua interdependência e não cooperem entre si – o que depende da relação das elasticidades-preço da demanda e da oferta. A despeito da possibilidade de efeitos benéficos, as doutrinas de defesa da concorrência brasileira e nas demais jurisdições, como EUA e Comunidade Européia, aplicam de maneira equivocada o conceito de poder compensatório ou ignoram por completo sua existência. Há que se considerar, contudo, que o objetivo da política antitruste e o da criação de poder compensatório estão alinhados: equilíbrio de assimetrias de poder nas relações entre os agentes, coibindo o exercício abusivo do poder de uma das partes na transação. Verifica-se, portanto, uma incongruência entre a jurisprudência e a teoria econômica. O conflito na aplicação do conceito de poder compensatório pela doutrina antitruste pode ser nitidamente observado no mercado de saúde suplementar brasileiro. Um fenômeno verificado nesse setor é a coordenação de médicos em cooperativas para fazer frente ao exercício de poder de compra por parte das operadoras de planos de saúde. Essa ação concertada tem sido condenada pelas autoridades de defesa da concorrência com base na interpretação de que a coordenação entre médicos constitui formação de cartel, passível de condenação pelas autoridades antitruste. A análise empírica corrobora as proposições teóricas: no setor de saúde suplementar, pelo menos na dimensão preço, existe a possibilidade de efeitos positivos associados ao poder compensatório. Destaca-se, contudo, que esse resultado estaria associado às cooperativas condenadas pelo CADE, que devem representar o grupo de associações que efetivamente deteriam poder econômico para equilibrar a assimetria de poder na negociação com as operadoras de planos de saúde. Diante dessa constatação, é importante reavaliar as decisões do CADE acerca das cooperativas médicas enquanto política pública que visa aumentar o bem-estar social.

Food-Retail Development and the Myth of Everyday Low Prices: The Case of Brazil

This article analyses the changes in Brazilian food retailing by investigating the co-existence of, and the pricing variation across, large supermarket chains and small independent supermarkets. It uses cointegration tests to show that, despite the widespread belief that small supermarkets are inefficient and charge higher prices, they in fact charge lower prices. Accordingly, in contrast to the prevailing literature on food-retail development, competition in food retail is complex and cannot be described as a simple Darwinian process of market concentration. The article explores the survival of small retail and its consequences for the current discussion on modern food retail in developing countries.

Market, Management and Profession. Social Business in the Polder

In a recent policy document of the organized employers in the care and welfare sector in The Netherlands (the MO Group), directors and board members of care and welfare institutions present themselves as "social entrepreneurs", managing their institutions as look-a like commercial companies. They are hardly criticized and there is not any countervailing power of significance. The workers are focusing on their own specialized professional fields and divided as a whole. Many government officials are in favour or do not bother. The relatively small number of intellectual workers in Dutch care and welfare are fragmented and pragmatic. From a democratic point of view this is a worrying situation. From a professional point of view the purpose and functions of professional care and welfare work are at stake. The penetration of market mechanisms and the take-over by commercially orientated managers result from unquestioned adaptation of Anglo-Saxon policy in The Netherlands in the 1990's, following the crisis of the Welfare State in the late 1980's. The polder country is now confronted fully with the pressure and negative effects of unbalanced powers in the institutions, i.e. Managerialism. After years of silence, the two principal authentic critics of Dutch care and welfare, Harry Kunneman and Andries Baart, are no longer voices crying in the wilderness, but are getting a response from a growing number of worried workers and intellectuals. Kunneman and Baart warn against the restriction of professional space and the loss of normative values and standards in the profession. They are right. It is high time to make room for criticism and to start a debate about the future of the social professions in The Netherlands, better: in Europe. Research, discussion and action have to prove how worrying the everyday situation of professional workers is, what goals have to be set and what strategy to be chosen.

Weathering the crisis? Managing democracy at a national broadcaster

With post-2008 political and economic crises as its backdrop, this inquiry into the political roles and functions of public service broadcasting (PSB) in Ireland is principally concerned with examining the capacities for and actuality of critical and counter-hegemonic professional journalistic and institutional mediations of crisis. Recognising the diversity of influences on the normative identity of Irish PSB, the dissertation adopts a sociological approach that acknowledges the systemic embedding of media institutions in the broader field of power. An initial tracing of the formative impacts of endogenous and exogenous forces on the democratic horizons of PSB suggests that the present crisis conjuncture does not represent promising terrain for engendering critical crisis and recovery imaginaries. A methodologically diverse intra-institutional empirical research agenda aims to explore at close hand Irish PSB’s contingent navigation of crisis, encompassing ethnographic observation in the newsroom, practitioner interviews and textual analysis of broadcast output. These methods afford close analysis of practices of journalistic production and reflexivity, self-conceptions of the journalistic habitus, and ideological affinities of crisis framings in broadcast output. These analyses are supplemented by a participant observation study of the possibilities for public agenda-building in a key institutional venue of public participation in broadcasting governance. The findings offer an evidential basis for the arguments that the crisis has prompted only minimal changes to professional norms and practices of representation and inclusion; that journalistic crisis framings tend toward effecting hegemonic repair by lending support to neoliberal crisis and recovery imaginaries; and that the institutional openings for the building of public counterpower are highly constrained. The overall conclusion is made that the normative democratic orientation embedded in the professional and institutional projects of public service broadcasting help render it ill-equipped to act as a re-democratising countervailing power against the democratic regressions engendered by the present crisis of democratic capitalism.

Comparação entre métodos para mensuração da potência aeróbia em atletas tetraplégicos= : Comparison of methods for aerobic power assessment in athletes with tetraplegia

Universidade Estadual de Campinas . Faculdade de Educação Física

Reliability and discriminatory power of methods for dental plaque quantification

OBJECTIVE: This in situ study evaluated the discriminatory power and reliability of methods of dental plaque quantification and the relationship between visual indices (VI) and fluorescence camera (FC) to detect plaque. MATERIAL AND METHODS: Six volunteers used palatal appliances with six bovine enamel blocks presenting different stages of plaque accumulation. The presence of plaque with and without disclosing was assessed using VI. Images were obtained with FC and digital camera in both conditions. The area covered by plaque was assessed. Examinations were done by two independent examiners. Data were analyzed by Kruskal-Wallis and Kappa tests to compare different conditions of samples and to assess the inter-examiner reproducibility. RESULTS: Some methods presented adequate reproducibility. The Turesky index and the assessment of area covered by disclosed plaque in the FC images presented the highest discriminatory powers. CONCLUSION: The Turesky index and images with FC with disclosing present good reliability and discriminatory power in quantifying dental plaque.

Power Secant Method applied to natural frequency extraction of Timoshenko beam structures

This work deals with an improved plane frame formulation whose exact dynamic stiffness matrix (DSM) presents, uniquely, null determinant for the natural frequencies. In comparison with the classical DSM, the formulation herein presented has some major advantages: local mode shapes are preserved in the formulation so that, for any positive frequency, the DSM will never be ill-conditioned; in the absence of poles, it is possible to employ the secant method in order to have a more computationally efficient eigenvalue extraction procedure. Applying the procedure to the more general case of Timoshenko beams, we introduce a new technique, named ""power deflation"", that makes the secant method suitable for the transcendental nonlinear eigenvalue problems based on the improved DSM. In order to avoid overflow occurrences that can hinder the secant method iterations, limiting frequencies are formulated, with scaling also applied to the eigenvalue problem. Comparisons with results available in the literature demonstrate the strength of the proposed method. Computational efficiency is compared with solutions obtained both by FEM and by the Wittrick-Williams algorithm.

Living Our Lives on the Edge: Power, Space and Sexual Orientation in Cape Town Townships, South Africa

Much of social science literature about South African cities fails to represent its complex spectrum of sexual practices and associated identities. The unintended effects of such representations are that a compulsory heterosexuality is naturalised in, and reiterative with, dominant constructions of blackness in townships. In this paper, we argue that the assertion of discreet lesbian and gay identities in black townships of a South African city such as Cape Town is influenced by the historical racial and socio-economic divides that have marked urban landscape. In their efforts to recoup a positive sense of gendered personhood, residents have constructed a moral economy anchored in reproductive heterosexuality. We draw upon ethnographic data to show how sexual minorities live their lives vicariously in spaces they have prised open within the extant sex/gender binary. They are able to assert the identities of moffie and man-vrou (mannish woman) without threatening the dominant ideology of heterosexuality.

A high voltage pulse power supply for metal plasma immersion ion implantation and deposition

We describe the design and implementation of a high voltage pulse power supply (pulser) that supports the operation of a repetitively pulsed filtered vacuum arc plasma deposition facility in plasma immersion ion implantation and deposition (Mepiiid) mode. Negative pulses (micropulses) of up to 20 kV in magnitude and 20 A peak current are provided in gated pulse packets (macropulses) over a broad range of possible pulse width and duty cycle. Application of the system consisting of filtered vacuum arc and high voltage pulser is demonstrated by forming diamond-like carbon (DLC) thin films with and without substrate bias provided by the pulser. Significantly enhanced film/substrate adhesion is observed when the pulser is used to induce interface mixing between the DLC film and the underlying Si substrate. (C) 2010 American Institute of Physics. [doi:10.1063/1.3518969]

The force, power, and energy of the 100 meter sprint

At the 2008 Summer Olympics in Beijing, Usain Bolt broke the world record for the 100 m sprint. Just one year later, at the 2009 World Championships in Athletics in Berlin he broke it again. A few months after Beijing, Eriksen [Am. J. Phys. 77, 224-228 (2009)] studied Bolt's performance and predicted that Bolt could have run about one-tenth of a second faster, which was confirmed in Berlin. In this paper we extend the analysis of Eriksen to model Bolt's velocity time dependence for the Beijing 2008 and Berlin 2009 records. We deduce the maximum force, the maximum power, and the total mechanical energy produced by Bolt in both races. Surprisingly, we conclude that all of these values were smaller in 2009 than in 2008.

Power-law creep behavior of a semiflexible chain

Rheological properties of adherent cells are essential for their physiological functions, and microrheological measurements on living cells have shown that their viscoelastic responses follow a weak power law over a wide range of time scales. This power law is also influenced by mechanical prestress borne by the cytoskeleton, suggesting that cytoskeletal prestress determines the cell's viscoelasticity, but the biophysical origins of this behavior are largely unknown. We have recently developed a stochastic two-dimensional model of an elastically joined chain that links the power-law rheology to the prestress. Here we use a similar approach to study the creep response of a prestressed three-dimensional elastically jointed chain as a viscoelastic model of semiflexible polymers that comprise the prestressed cytoskeletal lattice. Using a Monte Carlo based algorithm, we show that numerical simulations of the chain's creep behavior closely correspond to the behavior observed experimentally in living cells. The power-law creep behavior results from a finite-speed propagation of free energy from the chain's end points toward the center of the chain in response to an externally applied stretching force. The property that links the power law to the prestress is the chain's stiffening with increasing prestress, which originates from entropic and enthalpic contributions. These results indicate that the essential features of cellular rheology can be explained by the viscoelastic behaviors of individual semiflexible polymers of the cytoskeleton.

Angular-planar CMB power spectrum

Gaussianity and statistical isotropy of the Universe are modern cosmology's minimal set of hypotheses. In this work we introduce a new statistical test to detect observational deviations from this minimal set. By defining the temperature correlation function over the whole celestial sphere, we are able to independently quantify both angular and planar dependence (modulations) of the CMB temperature power spectrum over different slices of this sphere. Given that planar dependence leads to further modulations of the usual angular power spectrum C(l), this test can potentially reveal richer structures in the morphology of the primordial temperature field. We have also constructed an unbiased estimator for this angular-planar power spectrum which naturally generalizes the estimator for the usual C(l)'s. With the help of a chi-square analysis, we have used this estimator to search for observational deviations of statistical isotropy in WMAP's 5 year release data set (ILC5), where we found only slight anomalies on the angular scales l = 7 and l = 8. Since this angular-planar statistic is model-independent, it is ideal to employ in searches of statistical anisotropy (e.g., contaminations from the galactic plane) and to characterize non-Gaussianities.

Expression of genes related to muscle plasticity after strength and power training regimens

The purpose of our study was to compare the effects of 8-week progressive strength and power training regimens on strength gains and muscle plasticity [muscle fiber hypertrophy and phenotype shift, mammalian target of rapamycin (mTOR), regulatory-associated protein of mTOR (RAPTOR), rapamycin-insensitive companion of m-TOR (RICTOR), calcineurin and calcipressin gene expression]. Twenty-nine physically active subjects were divided into three groups: strength training (ST), power training (PT) and control (C). Squat 1 RM and muscle biopsies were obtained before and after the training period. Strength increased similarly for both ST and PT groups (P < 0.001). Fiber types I, IIa and IIb presented hypertrophy main time effect (P < 0.05). Only type IIb percentage decreased from pre- to post-test (main time effect, P < 0.05). mTOR and RICTOR mRNA expression increased similarly from pre- to post-test (P < 0.01). RAPTOR increased after training for both groups (P < 0.0001), but to a greater extent in the ST (P < 0.001) than in the PT group. 4EBP-1 decreased after training when the ST and PT groups were pooled (P < 0.05). Calcineurin levels did not change after training, while calcipressin increased similarly from pre- to post-test (P < 0.01). In conclusion, our data indicate that these training regimens produce similar performance improvements; however, there was a trend toward greater hypertrophy-related gene expression and muscle fiber hypertrophy in the ST group.

Is acute static stretching able to reduce the time to exhaustion at power output corresponding to maximal oxygen uptake?

Samogin Lopes, FA, Menegon, EM, Franchini, E, Tricoli, V, and de M. Bertuzzi, RC. Is acute static stretching able to reduce the time to exhaustion at power output corresponding to maximal oxygen uptake? J Strength Cond Res 24(6): 1650-1656, 2010-This study analyzed the effect of an acute static stretching bout on the time to exhaustion (T(lim)) at power output corresponding to (V) over dotO(2)max. Eleven physically active male subjects (age 22.3 +/- 2.8 years, (V) over dotO(2)max 2.7 +/- 0.5 L . min(-1)) completed an incremental cycle ergometer test, 2 muscle strength tests, and 2 maximal tests to exhaustion at power output corresponding to (V) over dotO(2)max with and without a previous static stretching bout. The T(lim) was not significantly affected by the static stretching (164 +/- 28 vs. 150 +/- 26 seconds with and without stretching, respectively, p = 0.09), but the time to reach (V) over dotO(2)max (118 +/- 22 vs. 102 +/- 25 seconds), blood-lactate accumulation immediately after exercise (10.7 +/- 2.9 vs. 8.0 +/- 1.7 mmol . L(-1)), and oxygen deficit (2.4 +/- 0.9 vs. 2.1 +/- 0.7 L) were significantly reduced (p <= 0.02). Thus, an acute static stretching bout did not reduce T(lim) at power output corresponding to (V) over dotO(2)max possibly by accelerating aerobic metabolism activation at the beginning of exercise. These results suggest that coaches and practitioners involved with aerobic dependent activities may use static stretching as part of their warm-up routines without fear of diminishing high-intensity aerobic exercise performance.