21,783 research outputs found
Coping with loss: cell adaptation to cytoskeleton disruption
Unravelling the role of cytoskeleton regulators may be complicated by adaptations to experimental manipulations. In this issue of Developmental Cell, Cerikan et al. (2016) reveal how acute effects of DOCK6 RhoGEF depletion on RAC1 and CDC42 activation are reversed over time by compensatory mechanisms that re-establish cellular homeostasis
Employees’ Choice of Method of Pay
Who chooses what type of pay? The costs and benefits of “flexible” and “cafeteria-style” benefit plans have been discussed for some time. Additionally, many papers have considered the potential costs and benefits of certain types of pay plans (e.g. salaries versus piece rates). In this paper, we use detailed data from a specific firm that annually set the total compensation level for each of its employees but then did something extremely unusual. At the start of each pay year, the firm set an exchange rate for the dollar trade-off between cash pay and stock option pay. It then gave every employee nearly complete choice over the fraction of their pay that was contingent (stock options, bonus) versus guaranteed (salary). There are several empirical findings. There is substantial variation in the choice of contingent pay with some workers choosing almost all base pay and others choosing almost entirely stock options. Younger employees, more experienced employees, higher paid employees, and male employees are more likely to allocate a larger fraction of their total compensation to at-risk alternatives. The robustness of these results varies somewhat depending on the empirical specification and set of covariates used
The Value of Stock Options to Non-Executive Employees
This study empirically investigates the value employees place on stock options using information from the option exercise behavior of individuals. Employees hold options for another period if the value from holding them and reserving the right to exercise them later is higher than the value of exercising them immediately and collecting a profit equal to the stock price minus the exercise price. This simple model implies the hazard describing employee exercise behavior reveals information about the value to employees of holding options another time period. We show the parameters of this model are identified with data on multiple option grants per employee and we apply this model to the disposition of options received in the 1990s by a sample of over 2000 middle-level managers from a large, established firm outside of manufacturing. Exercise behavior is modeled using a random effects probit model of monthly exercise behavior that is estimated using simulated maximum likelihood estimation methods. Our estimates show there is substantial heterogeneity (observed and unobserved) among employees in the value they place on their options. Our estimates show most employees value their options at a value greater than the option's Black-Scholes value.
Investigation of solid state traveling-wave- amplifier techniques for future satellite applications Quarterly progress report no. 4, 1 Mar. - 30 Jun. 1965
Solid state traveling wave amplifier techniques for satellite application
Investigation of solid state traveling-wave amplifier techniques for future satellite applications monthly progress report no. 5, 1 - 31 jan. 1965
Solid state traveling wave amplifier techniques for satellite application
Coarsening of Topological Defects in Oscillating Systems with Quenched Disorder
We use large scale simulations to study interacting particles in two
dimensions in the presence of both an ac drive and quenched disorder. As a
function of ac amplitude, there is a crossover from a low drive regime where
the colloid positions are highly disordered to a higher ac drive regime where
the system dynamically reorders. We examine the coarsening of topological
defects formed when the system is quenched from a disordered low ac amplitude
state to a high ac amplitude state. When the quench is performed close to the
disorder-order crossover, the defect density decays with time as a power law
with \alpha = 1/4 to 1/3. For deep quenches, in which the ac drive is increased
to high values such that the dynamical shaking temperature is strongly reduced,
we observe a logarithmic decay of the defect density into a grain boundary
dominated state. We find a similar logarithmic decay of defect density in
systems containing no pinning. We specifically demonstrate these effects for
vortices in thin film superconductors, and discuss implications for dynamical
reordering transition studies in these systems.Comment: 7 pages, 8 postscript figures; this extended version to appear in
Phys. Rev.
Emissivity coatings for low-temperature space radiators Quarterly progress report no. 1, 1 Jul. - 30 Sep. 1965
Emissivity coatings for low temperature spacecraft radiator
Viscous/potential flow about multi-element two-dimensional and infinite-span swept wings: Theory and experiment
The viscous subsonic flow past two-dimensional and infinite-span swept multi-component airfoils is studied theoretically and experimentally. The computerized analysis is based on iteratively coupled boundary layer and potential flow analysis. The method, which is restricted to flows with only slight separation, gives surface pressure distribution, chordwise and spanwise boundary layer characteristics, lift, drag, and pitching moment for airfoil configurations with up to four elements. Merging confluent boundary layers are treated. Theoretical predictions are compared with an exact theoretical potential flow solution and with experimental measures made in the Ames 40- by 80-Foot Wind Tunnel for both two-dimensional and infinite-span swept wing configurations. Section lift characteristics are accurately predicted for zero and moderate sweep angles where flow separation effects are negligible
ROCK signalling induced gene expression changes in mouse pancreatic ductal adenocarcinoma cells
The RhoA and RhoC GTPases act via the ROCK1 and ROCK2 kinases to promote actomyosin contraction, resulting in directly induced changes in cytoskeleton structures and altered gene transcription via several possible indirect routes. Elevated activation of the Rho/ROCK pathway has been reported in several diseases and pathological conditions, including disorders of the central nervous system, cardiovascular dysfunctions and cancer. To determine how increased ROCK signalling affected gene expression in pancreatic ductal adenocarcinoma (PDAC) cells, we transduced mouse PDAC cell lines with retroviral constructs encoding fusion proteins that enable conditional activation of ROCK1 or ROCK2, and subsequently performed RNA sequencing (RNA-Seq) using the Illumina NextSeq 500 platform. We describe how gene expression datasets were generated and validated by comparing data obtained by RNA-Seq with RT-qPCR results. Activation of ROCK1 or ROCK2 signalling induced significant changes in gene expression that could be used to determine how actomyosin contractility influences gene transcription in pancreatic cancer
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