Perceptions of Professional Practice and Work Environment of New Graduates in a Nurse Residency Program

New nurses continue to face challenging work environments and high expectations for professional competence as they enter practice. Nurse residency programs are gaining prominence as a mechanism to ease new graduates’ transition to practice. This study examined new graduates’ perceptions of their professional practice competence and work environment throughout a yearlong nurse residency program. Employing a repeated measures design, data were collected at baseline, at 6 months, and at 12 months. Results showed that job satisfaction was significantly lowest at 6 months and highest at 12 months. Job stress was found to be lowest at 12 months and organizational commitment was highest at baseline. Of the variables related to professional practice, clinical decision-making was highest at 12 months and quality of nursing performance significantly increased at each measurement point. These data add to the growing evidence supporting the efficacy of nurse residency programs

Importance of direct and indirect triggered seismicity

Using the simple ETAS branching model of seismicity, which assumes that each earthquake can trigger other earthquakes, we quantify the role played by the cascade of triggered seismicity in controlling the rate of aftershock decay as well as the overall level of seismicity in the presence of a constant external seismicity source. We show that, in this model, the fraction of earthquakes in the population that are aftershocks is equal to the fraction of aftershocks that are indirectly triggered and is given by the average number of triggered events per earthquake. Previous observations that a significant fraction of earthquakes are triggered earthquakes therefore imply that most aftershocks are indirectly triggered by the mainshock.Comment: Latex document of 17 pages + 2 postscript figure

Predictors of New Graduate Nurses’ Organizational Commitment During a Nurse Residency Program

Retaining newly graduated nurses is critical for organizations because of the significant cost of turnover. Since commitment to an organization is associated with decreased turnover intent, understanding factors that influence new graduates’ organizational commitment is important. In a sample of nurse residency program participants, predictors of organizational commitment over time were explored. Perceptions of the work environment, particularly job satisfaction and job stress, were found to be most influential. Nurse residency programs provide extended opportunities to model professional role behaviors for new nurses, enhance knowledge development and clinical application, and promote successful integration to the work environment (Bratt, 2009). Despite these benefits, only 21% of new graduates reported having a formal internship or residency program and 6% had no formal orientation (Kovner et al., 2007). In a national survey of registered nurses (RNs) conducted by the Department of Health and Human Services (2010), it was revealed that almost 40% of new graduates plan to leave their current position within 3 years and almost 22% had already changed position or employer. For those new nurses who left their position, most of the reasons (73%) centered on issues related to the characteristics of the workplace, with stressful work environment being cited most frequently, followed by lack of good management and inadequate staffing. Accreditation organizations including the Commission on Collegiate Nursing Education (2008) and the National Council of State Boards of Nursing (2009a) have advocated for the development of transition to practice programs for newly graduated nurses. In addition, the recently released report of the Institute of Medicine (2010) put forth a key recommendation for organizations to provide nurse residency programs for newly licensed nurses. This report also advocates for the need to evaluate the outcomes of these programs, including their influence on patient outcomes and the retention and competency development of new nurses

Relation between stress heterogeneity and aftershock rate in the rate-and-state model

We estimate the rate of aftershocks triggered by a heterogeneous stress change, using the rate-and-state model of Dieterich [1994].We show that an exponential stress distribution Pt(au) ~exp(-tautau_0) gives an Omori law decay of aftershocks with time ~1/t^p, with an exponent p=1-A sigma_n/tau_0, where A is a parameter of the rate-and-state friction law, and \sigma_n the normal stress. Omori exponent p thus decreases if the stress "heterogeneity" tau_0 decreases. We also invert the stress distribution P(tau) from the seismicity rate R(t), assuming that the stress does not change with time. We apply this method to a synthetic stress map, using the (modified) scale invariant "k^2" slip model [Herrero and Bernard, 1994]. We generate synthetic aftershock catalogs from this stress change.The seismicity rate on the rupture area shows a huge increase at short times, even if the stress decreases on average. Aftershocks are clustered in the regions of low slip, but the spatial distribution is more diffuse than for a simple slip dislocation. Because the stress field is very heterogeneous, there are many patches of positive stress changes everywhere on the fault.This stochastic slip model gives a Gaussian stress distribution, but nevertheless produces an aftershock rate which is very close to Omori's law, with an effective p<=1, which increases slowly with time. We obtain a good estimation of the stress distribution for realistic catalogs, when we constrain the shape of the distribution. However, there are probably other factors which also affect the temporal decay of aftershocks with time. In particular, heterogeneity of A\sigma_n can also modify the parameters p and c of Omori's law. Finally, we show that stress shadows are very difficult to observe in a heterogeneous stress context.Comment: In press in JG

Regional variations in the diffusion of triggered seismicity

[1] We determine the spatiotemporal characteristics of interearthquake triggering in the International Seismological Centre catalogue on regional and global scales. We pose a null hypothesis of spatially clustered, temporally random seismicity, and determine a residual pair correlation function for triggered events against this background. We compare results from the eastern Mediterranean, 25 Flinn-Engdahl seismic regions, and the global data set. The null hypothesis cannot be rejected for distances greater than 150 km, providing an upper limit to triggering distances that can be distinguished from temporally uncorrelated seismicity in the stacked data at present. Correlation lengths L andmean distances between triggered events hri are on the order of 10–50 km, but can be as high as 100 km in subduction zones. These values are not strongly affected by magnitude threshold, but are comparable to seismogenic thicknesses, implying a strong thermal control on correlation lengths. The temporal evolution of L and hri is well fitted by a power law, with an exponent H 0.1 ± 0.05. This is much lower than the value H = 0.5 expected for Gaussian diffusion in a homogenous medium. We observe clear regional variations in L, hri and H that appear to depend on tectonic setting. A detectable transition to a more rapid diffusion regime occurs in some cases at times greater than 100–200 days, possibly due to viscoelastic processes in the ductile lower crust

Effects of Nitrogen Limitation on Hydrological Processes in CLM4-CN

http://globalchange.mit.edu/research/publications/2253The role of nitrogen limitation on photosynthesis downregulation and stomatal conductance has a significant influence on evapotranspiration and runoff. In the current Community Land Model with coupled Carbon and Nitrogen cycles (CLM4-CN), however, the carbon and water coupling in stomata is not linked to nitrogen limitation. We modify the incomplete linkages between carbon, nitrogen, and water, and examine how nitrogen limitation affects hydrological processes in CLM4-CN. In addition, we evaluate if the modification can improve the simulation of carbon and water fluxes. Applying the effects of nitrogen limitation on stomatal conductance significantly decreases leaf photosynthesis. It leads to a reduction in canopy transpiration, thereby increasing total runoff, mainly due to increasing subsurface runoff. More available soil water for vegetation from the reduced transpiration helps increase gross primary productivity (GPP) in the relatively moisture-limited regions of grassland/steppe and savanna. But, in the tropics and boreal forest regions, changes in soil water by nitrogen limitation are insignificant, and GPP decreases directly by down-regulated leaf photosynthesis. Decreasing canopy transpiration and increasing runoff from nitrogen limitation improve simulating latent heat flux and runoff by reducing high biases for latent heat flux in the tropics and low biases for runoff in the tropics and northern high-latitudes. In addition, the CLM4-CN with leaf-level nitrogen limitation reduces high model biases in tropical GPP. Thus, nitrogen limitation on the leaf-level significantly affects hydrological processes in CLM4-CN and improves the simulation of carbon and water fluxes.The study was supported by the joint project between Lehigh and MIT Joint Program on the Science and Policy of Global Change through a consortium of industrial sponsors and Federal grants

Importance of small earthquakes for stress transfers and earthquake triggering

We estimate the relative importance of small and large earthquakes for static stress changes and for earthquake triggering, assuming that earthquakes are triggered by static stress changes and that earthquakes are located on a fractal network of dimension D. This model predicts that both the number of events triggered by an earthquake of magnitude m and the stress change induced by this earthquake at the location of other earthquakes increase with m as \~10^(Dm/2). The stronger the spatial clustering, the larger the influence of small earthquakes on stress changes at the location of a future event as well as earthquake triggering. If earthquake magnitudes follow the Gutenberg-Richter law with b>D/2, small earthquakes collectively dominate stress transfer and earthquake triggering, because their greater frequency overcomes their smaller individual triggering potential. Using a Southern-California catalog, we observe that the rate of seismicity triggered by an earthquake of magnitude m increases with m as 10^(alpha m), where alpha=1.00+-0.05. We also find that the magnitude distribution of triggered earthquakes is independent of the triggering earthquake magnitude m. When alpha=b, small earthquakes are roughly as important to earthquake triggering as larger ones. We evaluate the fractal correlation dimension of hypocenters D=2 using two relocated catalogs for Southern California, and removing the effect of short-term clustering. Thus D=2alpha as predicted by assuming that earthquake triggering is due to static stress. The value D=2 implies that small earthquakes are as important as larger ones for stress transfers between earthquakes.Comment: 14 pages, 7 eps figures, latex. In press in J. Geophys. Re

Effects of nitrogen limitation on hydrological processes in CLM4-CN

[1] The role of nitrogen limitation on photosynthesis downregulation and stomatal conductance has a significant influence on evapotranspiration and runoff. In the current Community Land Model with coupled Carbon and Nitrogen cycles (CLM4-CN), however, the carbon and water coupling in stomata is not linked to nitrogen limitation. We modify the incomplete linkages between carbon, nitrogen, and water, and examine how nitrogen limitation affects hydrological processes in CLM4-CN. We then evaluate if the modification can improve the simulation of carbon and water fluxes. Applying the effects of nitrogen limitation on stomatal conductance significantly decreases leaf photosynthesis. It leads to a reduction in canopy transpiration, thereby increasing total runoff, mainly due to increasing subsurface runoff. More available soil water for vegetation from the reduced transpiration helps increase gross primary productivity (GPP) in the relatively moisture-limited regions of grassland/steppe and savanna. However, in the tropics and boreal forest regions, changes in soil water by nitrogen limitation are insignificant, and GPP decreases directly by down-regulated leaf photosynthesis. Decreasing canopy transpiration and increasing runoff from nitrogen limitation improve simulating latent heat flux and runoff by reducing high biases for latent heat flux in the tropics and low biases for runoff in the tropics and northern high latitudes. In addition, the CLM4-CN with leaf-level nitrogen limitation reduces model biases in tropical GPP. Nitrogen limitation on the leaf-level significantly affects hydrological processes in CLM4-CN and improves the simulation of carbon and water fluxes. This process should be included with other recent improvements to reduce model biases as much as possible