The construction of saturated 2Rk-p designs

Combinatorial and sequential analyses for optimization of saturated design

Tracer studies of reaction mechanisms: the photolysis of acetone labelled with (^14)C

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Research into fundamental phenomena associated with spacecraft electrochemical devices, calorimetry of nickel-cadmium cells Progress report, 1 Oct. - 31 Dec. 1967

Calorimetry of nickel cadmium cells for spacecraft electrochemical system

DYNAMIC BALANCE IN ALPINE SKIERS

There are more than 200 million alpine skiers worldwide (Hunter, 1999) but currently ski equipment does not protect the knee as it does the rest of the lower leg and there has been a dramatic rise in knee ligament and meniscus injuries associated with alpine skiing in recent years (Pecina, 2002). Pujol et al. (2007) stated that 45-60% of knee injuries during alpine skiing involve the ACL. Balance is an important component of performance in skiing (Laskowski, 1999) and Natri et al. (1999) found that many skiers sustaining an injury believed they were only temporarily off balance and capable of regaining control. The three most common mechanisms of injury to the knee in skiing are linked to a loss of dynamic balance (Rossi et al., 2003)

Living on the edge of chaos: minimally nonlinear models of genetic regulatory dynamics

Linearized catalytic reaction equations modeling e.g. the dynamics of genetic regulatory networks under the constraint that expression levels, i.e. molecular concentrations of nucleic material are positive, exhibit nontrivial dynamical properties, which depend on the average connectivity of the reaction network. In these systems the inflation of the edge of chaos and multi-stability have been demonstrated to exist. The positivity constraint introduces a nonlinearity which makes chaotic dynamics possible. Despite the simplicity of such minimally nonlinear systems, their basic properties allow to understand fundamental dynamical properties of complex biological reaction networks. We analyze the Lyapunov spectrum, determine the probability to find stationary oscillating solutions, demonstrate the effect of the nonlinearity on the effective in- and out-degree of the active interaction network and study how the frequency distributions of oscillatory modes of such system depend on the average connectivity.Comment: 11 pages, 5 figure

Controlling the uncontrolled: Are there incidental experimenter effects on physiologic responding?

The degree to which experimenters shape participant behavior has long been of interest in experimental social science research. Here, we extend this question to the domain of peripheral psychophysiology, where experimenters often have direct, physical contact with participants, yet researchers do not consistently test for their influence. We describe analytic tools for examining experimenter effects in peripheral physiology. Using these tools, we investigate nine data sets totaling 1,341 participants and 160 experimenters across different roles (e.g., lead research assistants, evaluators, confederates) to demonstrate how researchers can test for experimenter effects in participant autonomic nervous system activity during baseline recordings and reactivity to study tasks. Our results showed (a) little to no significant variance in participants' physiological reactivity due to their experimenters, and (b) little to no evidence that three characteristics of experimenters that are well known to shape interpersonal interactions-status (using five studies with 682 total participants), gender (using two studies with 359 total participants), and race (in two studies with 554 total participants)-influenced participants' physiology. We highlight several reasons that experimenter effects in physiological data are still cause for concern, including the fact that experimenters in these studies were already restricted on a number of characteristics (e.g., age, education). We present recommendations for examining and reducing experimenter effects in physiological data and discuss implications for replication