1,288 research outputs found
Moving on up: The Rooney rule and minority hiring in the NFL
Abstract Detecting and quantifying racial discrimination in the labor market is difficult. The sports industry offers a wealth of data and specific hiring practices which mitigates this difficulty. The Rooney Rule requires National Football League teams to interview at least one minority candidate when hiring a head coach. We examine a unique data set of high-level assistant coaches (offensive and defensive coordinators) from the beginning of the 1970 season through the beginning of the 2009 season to determine whether race is a factor in NFL teams' decisions to promote these assistants to head coach. Using logit and hazard models that control for age, experience and performance, we conclude that conditional on a coach reaching coordinator status, there is no evidence that race influences head coach hiring decisions. We also find no evidence that the Rooney Rule has increased the number of minority head coaches
Sagittal jaw position in relation to body posture in adult humans – a rasterstereographic study
BACKGROUND: The correlations between the sagittal jaw position and the cranio – cervical inclination are described in literature. Only few studies focus on the sagittal jaw position and the body posture using valid and objective orthopaedic examination methods. The aim of this study was to test the hypothesis that patients with malocclusions reveal significant differences in body posture compared to those without (upper thoracic inclination, kyphotic angle, lordotic angle and lower lumbar inclination). METHODS: Eighty-four healthy adult patients (with a mean age = 25.6 years and ranging from 16.1 to 55.8 years) were examined with informed consent. The orthodontic examination horizontal overjet (distance between upper and lower incisors) was determined by using an orthodontic digital sliding calliper. The subjects were subdivided in respect of the overjet with the following results: 18 revealed a normal overjet (Class I), 38 had an increased overjet (Class II) and 28 had an reversed overjet (Class III). Rasterstereography was used to carry out a three – dimensional back shape analysis. This method is based on photogrammetry. A three-dimensional shape was produced by analysing the distortion of parallel horizontal white light lines projected on the patient's back, followed by mathematical modelling. On the basis of the sagittal profile the upper thoracic inclination, the thoracic angle, the lordotic angle and the pelvic inclination were determined with a reported accuracy of 2.8° and the correlations to the sagittal jaw position were calculated by means of ANOVA, Scheffé and Kruskal-Wallis procedures. RESULTS: Between the different overjet groups, no statistically significant differences or correlations regarding the analysed back shape parameters could be obtained. However, comparing males and females there were statistically significant differences in view of the parameters 'lordotic angle' and 'pelvic inclination'. CONCLUSION: No correlations between overjet and variables of the thoracic, lordotic or the pelvic inclination could be observed
Boolean Dynamics with Random Couplings
This paper reviews a class of generic dissipative dynamical systems called
N-K models. In these models, the dynamics of N elements, defined as Boolean
variables, develop step by step, clocked by a discrete time variable. Each of
the N Boolean elements at a given time is given a value which depends upon K
elements in the previous time step.
We review the work of many authors on the behavior of the models, looking
particularly at the structure and lengths of their cycles, the sizes of their
basins of attraction, and the flow of information through the systems. In the
limit of infinite N, there is a phase transition between a chaotic and an
ordered phase, with a critical phase in between.
We argue that the behavior of this system depends significantly on the
topology of the network connections. If the elements are placed upon a lattice
with dimension d, the system shows correlations related to the standard
percolation or directed percolation phase transition on such a lattice. On the
other hand, a very different behavior is seen in the Kauffman net in which all
spins are equally likely to be coupled to a given spin. In this situation,
coupling loops are mostly suppressed, and the behavior of the system is much
more like that of a mean field theory.
We also describe possible applications of the models to, for example, genetic
networks, cell differentiation, evolution, democracy in social systems and
neural networks.Comment: 69 pages, 16 figures, Submitted to Springer Applied Mathematical
Sciences Serie
The Elusive Rentier Rich: Piketty's Data Battles and the Power of Absent Evidence
The popularity of Thomas Piketty?s research on wealth inequality has drawn attention to a curious question: why was widening wealth inequality largely neglected by mainstream economists in recent decades? To explore and explain that neglect, I draw on the writing of the early neoclassical economist John Bates Clark, who introduced the notion of the marginal productivity of income distribution at the end of the nineteenth century. I then turn to Piketty?s Capital in order to analyze the salience of marginal productivity theories of income today. I suggest that most of the criticism and praise for Piketty?s research is focused on data that are accessible and measurable, obscuring attention to questions over whether current methods for measuring economic capital are defensible or not. My overarching aim is to explore how ?absent? data in economics as a whole help to reinforce blind spots within mainstream economic theory
SUSTAINABLE DEVELOPMENT AND THE PROCESS OF JUSTIFYING CHOICES IN A CONTROVERSIAL UNIVERSE
All in all, neither the path of the generic principle nor that of the reduction to existing principles would appear to be fully satisfactory as the basis for establishing the legitimacy of sustainable development or as a way of making sustainability a principle of legitimacy by its own. We should probably resign ourselves to seeing in this idea a composite construction, still striving towards the formation of a new "superior common principle", without this principle yet being able to be completely clarified and validated. What we have here is an example of the sort of "compromise" described by Boltanski and Thévenot (1991, p.338): "In the compromise, the participants abandon the idea of clarifying the principle of their agreement but endeavour to maintain a frame of mind aiming at the common good." If we want to consolidate the compromise developing around sustainability, it would be well advised to seek the support of tests using well-formed objects. To this end, steps should be taken to move the emphasis away from long-term and unknowable sustainability requirements and closer to secondbest criteria focused on the transitional developments and possible risks of intentional human action, the ways of managing the linking of the different temporalities in play -- as regards the biophysical phenomena, their understanding and the main worlds of legitimacy (Godard, 1992) -- and the introduction of deliberation within the present generations as to what they feel best describes their identity, those things they would like to pass on
Roentgen cephalometric analysis of ridge resorption and changes in jaw and occlusal relationships in immediate complete denture wearers
In eighteen subjects assigned for immediate complete upper and lower dentures, roentgen cephalometric recordings were made before extraction of the residual anterior dentition and 3 weeks, 3 months, 6 months and 1 year after denture insertion. The cephalometric analysis was based on electronic measurements of linear and angular morphological variables and computer head plots generated from 177 reference points (Walker, 1967), derived for each subject for each of the five observation stages. The reduction of the alveolar ridges was most rapid during the first 3 months of denture wear and particularly during the post-extraction period of 3 weeks. The reduction in anterior height of the lower ridge was on average twice as great as that of the upper ridge. The ridge resorption and the accompanying settling of the dentures on the basal seats, measured from lead shots inserted in the dentures, brought about an upward rotation of the mandible with a resulting decrease in occlusal vertical dimension and reduction in overjet of the dentures. In accordance with the amount of ridge reduction, these changes showed great individual variation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73577/1/j.1365-2842.1980.tb01466.x.pd
Obesity and craniofacial variables in subjects with obstructive sleep apnea syndrome: comparisons of cephalometric values
<p>Abstract</p> <p>Background</p> <p>The aim of this paper was to determine the most common craniofacial changes in patients suffering Obstructive Sleep Apnea Syndrome (OSAS) with regards to the degree of obesity. Accordingly, cephalometric data reported in the literature was searched and analyzed.</p> <p>Methods</p> <p>After a careful analysis of the literature from 1990 to 2006, 5 papers with similar procedural criteria were selected. Inclusion criteria were: recruitment of Caucasian patients with an apnea-hypopnea index (AHI) >10 as grouped in non-obese (Body Mass Index – [BMI] < 30) <it>vs</it>. obese (BMI ≥ 30).</p> <p>Results</p> <p>A low position of the hyoid bone was present in both groups. In non-obese patients, an increased value of the ANB angle and a reduced dimension of the cranial base (S-N) were found to be the most common finding, whereas major skeletal divergence (ANS-PNS ^Go-Me) was evident among obese patients. No strict association was found between OSAS and length of the soft palate.</p> <p>Conclusion</p> <p>In both non-obese and obese OSAS patients, skeletal changes were often evident; with special emphasis of intermaxillary divergence in obese patients. Unexpectedly, in obese OSAS patients, alterations of oropharyngeal soft tissue were not always present and did not prevail.</p
International comparisons of sectoral energy- and labour-productivity performance. Stylised facts and decomposition of trends
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