355 research outputs found
The Design Thinking Mindset: An Assessment Of What We Know And What We See In Practice
We review the design and management literature to identify and define key components of a design thinking mindset and report initial findings from fifteen in-depth interviews with innovation managers, who reflect on their practices while implementing design thinking in their organizations. Our study confirms a set of commonly understood and applied mindsets, but also reveals organizational constraints on translating cognition into behaviour. We argue that further mapping of design thinking mindsets and linking them to leadership theory provides a suitable point of departure for the study of design thinking and its role for innovation
A high-sensitivity laser-pumped Mx magnetometer
Abstract.: We discuss the design and performance of a laser-pumped cesium vapor magnetometer in the Mx configuration. The device will be employed in the control and stabilization of fluctuating magnetic fields and gradients in a new experiment searching for a permanent electric dipole moment of the neutron. We have determined the intrinsic sensitivity of the device to be 15 fT in a 1 Hz bandwidth, limited by technical laser noise. In the shot noise limit the magnetometer can reach a sensitivity of 10 fT in a 1 Hz bandwidth. We have used the device to study the fluctuations of a stable magnetic field in a multi-layer magnetic shield for integration times in the range of 2-100 seconds. The residual fluctuations for times up to a few minutes are traced back to the instability of the power supply used to generate the fiel
Sensitivity of double resonance alignment magnetometers
We present an experimental study of the intrinsic magnetometric sensitivity
of an optical/rf-frequency double resonance magnetometer in which linearly
polarized laser light is used in the optical pumping and detection processes.
We show that a semi-empirical model of the magnetometer can be used to describe
the magnetic resonance spectra. Then, we present an efficient method to predict
the optimum operating point of the magnetometer, i.e., the light power and rf
Rabi frequency providing maximum magnetometric sensitivity. Finally, we apply
the method to investigate the evolution of the optimum operating point with
temperature. The method is very efficient to determine relaxation rates and
thus allowed us to determine the three collisional disalignment cross sections
for the components of the alignment tensor. Both first and second harmonic
signals from the magnetometer are considered and compared
Experimental study of laser detected magnetic resonance based on atomic alignment
We present an experimental study of the spectra produced by
optical/radio-frequency double resonance in which resonant linearly polarized
laser light is used in the optical pumping and detection processes. We show
that the experimental spectra obtained for cesium are in excellent agreement
with a very general theoretical model developed in our group and we investigate
the limitations of this model. Finally, the results are discussed in view of
their use in the study of relaxation processes in aligned alkali vapors.Comment: 8 pages, 9 figures. Submitted to Phys. Rev. A. Related to
physics/060523
Evacuating Damaged and Destroyed Buildings on 9/11: Behavioral and Structural Barriers
Introduction
Evacuation of the World Trade Center (WTC) twin towers and surrounding buildings damaged in the September 11, 2001 attacks provides a unique opportunity to study factors that affect emergency evacuation of high rise buildings.
Problem
The goal of this study is to understand the extent to which structural and behavioral barriers and limitations of personal mobility affected evacuation by occupants of affected buildings on September 11, 2001.
Methods
This analysis included 5,023 civilian, adult enrollees within the World Trade Center Health Registry who evacuated the two World Trade Center towers and over 30 other Lower Manhattan buildings that were damaged or destroyed on September 11, 2001. Multinomial logistic regression was used to predict total evacuation time (less than 30 to ≤60 minutes, greater than 1 hour to less than 2 hours relative to ≤30 minutes) in relation to number of infrastructure barriers and number of behavioral barriers, adjusted for demographic and other factors.
Results
A higher percentage of evacuees reported encountering at least one behavioral barrier (84.9%) than reported at least one infrastructure barrier (51.9%). This pattern was consistent in all buildings except WTC 1, the first building attacked, where greater than 90% of evacuees reported encountering both types of barriers. Smoke and poor lighting were the most frequently-reported structural barriers. Extreme crowding, lack of communication with officials, and being surrounded by panicked crowds were the most frequently-reported behavioral barriers. Multivariate analyses showed evacuation time to be independently associated with the number of each type of barrier as well as gender (longer times for women), but not with the floor from which evacuation began. After adjustment, personal mobility impairment was not associated with increased evacuation time.
Conclusion
Because most high-rise buildings have unique designs, infrastructure factors tend to be less predictable than behavioral factors, but both need to be considered in developing emergency evacuation plans in order to decrease evacuation time and, consequently, risk of injury and death during an emergency evacuation
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Prenatal Exposure to Lead, δ-Aminolevulinic Acid, and Schizophrenia: Further Evidence
Background: A previously conducted study of prenatal lead exposure and schizophrenia using δ-aminolevulinic acid, a biologic marker of Pb exposure, in archived maternal serum samples collected from subjects enrolled in the Childhood Health and Development Study (1959–1966) based in Oakland, California, suggested a possible association between prenatal Pb exposure and the development of schizophrenia in later life. Objectives: In the present study we extend these findings using samples collected from the New England cohort of the National Collaborative Perinatal Project (1959–1966). Using similar methods, in this study we found results that suggest a comparable association in this cohort. Methods: We pooled matched sets of cases and controls from both the California and New England sites using a multilevel random-intercept logistic regression model, accounting for matching and site structure as well as adjusting for maternal age at delivery and maternal education. Results: The estimated odds ratio for schizophrenia associated with exposure corresponding to 15 μg/dL of blood Pb was 1.92 (95% confidence interval, 1.05–3.87; p = 0.03). Conclusion: Although several limitations constrain generalizability, these results are consistent with previous findings and provide further evidence for the role of early environmental exposures in the development of adult-onset psychiatric disorders
The actin-myosin regulatory MRCK kinases: regulation, biological functions and associations with human cancer
The contractile actin-myosin cytoskeleton provides much of the force required for numerous cellular activities such as motility, adhesion, cytokinesis and changes in morphology. Key elements that respond to various signal pathways are the myosin II regulatory light chains (MLC), which participate in actin-myosin contraction by modulating the ATPase activity and consequent contractile force generation mediated by myosin heavy chain heads. Considerable effort has focussed on the role of MLC kinases, and yet the contributions of the myotonic dystrophy-related Cdc42-binding kinases (MRCK) proteins in MLC phosphorylation and cytoskeleton regulation have not been well characterized. In contrast to the closely related ROCK1 and ROCK2 kinases that are regulated by the RhoA and RhoC GTPases, there is relatively little information about the CDC42-regulated MRCKα, MRCKβ and MRCKγ members of the AGC (PKA, PKG and PKC) kinase family. As well as differences in upstream activation pathways, MRCK and ROCK kinases apparently differ in the way that they spatially regulate MLC phosphorylation, which ultimately affects their influence on the organization and dynamics of the actin-myosin cytoskeleton. In this review, we will summarize the MRCK protein structures, expression patterns, small molecule inhibitors, biological functions and associations with human diseases such as cancer
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