13,507,071 research outputs found
The Speed of Adaptation in Large Asexual Populations
In large asexual populations, beneficial mutations have to compete with each
other for fixation. Here, I derive explicit analytic expressions for the rate
of substitution and the mean beneficial effect of fixed mutations, under the
assumptions that the population size N is large, that the mean effect of new
beneficial mutations is smaller than the mean effect of new deleterious
mutations, and that new beneficial mutations are exponentially distributed. As
N increases, the rate of substitution approaches a constant, which is equal to
the mean effect of new beneficial mutations. The mean effect of fixed mutations
continues to grow logarithmically with N. The speed of adaptation, measured as
the change of log fitness over time, also grows logarithmically with N for
moderately large N, and it grows double-logarithmically for extremely large N.
Moreover, I derive a simple formula that determines whether at given N
beneficial mutations are expected to compete with each other or go to fixation
independently. Finally, I verify all results with numerical simulations.Comment: 33 pages, 6 figures. Minor changes in discussion. To appear in
Genetic
The Effect of Psychiatric Rehabilitation on the Activity and Participation Level of Clients with Long-Term Psychiatric Disabilities
During the last decades of the 20th century, many psychiatric hospitals changed the living environments of their clients with long-term psychiatric disabilities.
We investigated the effect of this environmental psychiatric rehabilitation and normalization process on the activity and participation level of such clients residing in one Dutch psychiatric hospital. The seven years of panel research demonstrated that more normal living environments have a positive effect on clients’ activity and participation level. This is controlled for the fact that younger clients, and clients with a relative high activity and participation level were selected for these normal living environments.
Effect of laser-welding parameters on the heat input and weld-bead profile
Laser butt-welding of medium carbon steel was investigated using CW 1.5 kW CO2 laser. The effect of laser power (1.2 - 1.43 kW), welding speed (30 - 70 cm/min) and focal point position (-2.5 - 0 mm) on the heat input and the weld-bead geometry (i.e. penetration (P), welded zone width (W) and heat affected zone width (WHAZ)) was investigated using Response Surface Methodology (RSM). The experimental plan was based on Box-Behnken design. Linear and quadratic polynomial equations for predicting the heat input and the weld-bead geometry were developed. The results indicate that the proposed models predict the responses adequately within the limits of welding parameters being used. It is suggested that regression equations can be used to find optimum welding conditions for the desired criteria
Effect of Saccharum officinarum Juice Extract Additive on the Electrodeposition of Zinc on Mild Steel in Acid Chloride Solution
Experimental investigations have been performed to examine the electrodeposition of zinc on mild steel in acid chloride solution using as additive different concentrations of saccharum officinarum (sugarcane) juice extracts. The experiments were performed under different plating time, different additive concentrations and fixed pH conditions. Zinc electrodeposition on mild steel was performed using a DC – supply at defined operating parameters. The surface of the plated steel was examined using scanning electron microscopy (SEM); and Energy Dispersive Spectroscopy (EDS) for surface elemental composition analysis. Different surface characteristics were obtained depending upon the concentration of the additive and the plating time. The corrosion resistance of the plated surface was also determined by gravimetric method. The quality of electrodeposition of zinc was good as indicated by the plated surface microstructural morpholog
Validation of Observed Bedload Transport Pathways Using Morphodynamic Modeling
Phenomena related to braiding, including local scour and fill, channel bar development, migration
and avulsion, make numerical morphodynamic modeling of braided rivers challenging. This paper investigates
the performance of a Delft3D model, in a 2D depth-averaged formulation, to simulate the
morphodynamics of an anabranch of the Rees River (New Zealand). Model performance is evaluated using
data from field surveys collected on the falling limb of a major high flow, and using several sediment
transport formulas. Initial model results suggest that there is generally good agreement between observed and
modeled bed levels. However, some discrepancies in the bed level estimations were noticed, leading to bed
level, water depth and water velocity estimation errors
Efecto de una dosis de lidocaína y ketamina sobre el consumo intraoperatorio de opioides en pacientes sometidas a cirugía ginecológica electiva bajo anestesia general. Estudio piloto aleatorizado y controlado con placebo
Background and goal of study: there is evidence that perioperative intravenous ketamine and lidocaine reduce postoperative pain, postoperative opioids consumption, shortens hospital stay and accelerates intestinal function recovery. However, it has not been studied the beneficial effects in the intraoperative period. The aim of this study was to evaluate the effect of a single dose of lidocaine and ketamine on intraoperative opioids requirements in patients undergoing elective gynecological laparotomies under general anesthesia.
Materials and methods: we performed a single-centre, prospective, randomized, double-blinded, placebo-controlled study. We included 33 patients (11 in the ketamine group, 11 in the lidocaine group and 11 in the placebo group). Postoperative analgesia was accomplished by patient-controlled morphine. Patients were randomly assigned to receive either a 1.5 mg/kg of 2% lidocaine, 0.5 mg/kg of 5% ketamine or 0.9% saline bolus. The primary outcome was the opioids consumption during surgery. The secondary outcomes included:
emergence time, pain scores, opioids consumption within 24 h after surgery and side effects.
Results: decreased intraoperative opioids requirements were noted in the experimental groups (ketamine: 402.3±106.3 and lidocaine: 397.7±107.5, compared with saline: 561.4±97.1); p=0.001. We found a positive correlation between intraoperative opioids consumption and emergence time (r=0.864, p<0.001). There was no significant difference between the groups in VAS pain scores at rest within the first 24 postoperative hours. Total morphine consumption within 24 h after surgery did not differ significantly among the groups (placebo: 27.54±11.75; ketamine: 30.95±7.88; lidocaine 34.77±10.25; p=0.26). Postoperative nausea and vomiting were more common in placebo group (it was observed in 3 subjects in ketamine group, in 5 subjects in lidocaine group and in 9 subjects in placebo group; p=0.027).
Conclusion: our results do not support the use of intraoperative single dose of lidocaine or ketamine to reduce postoperative pain and postoperative opioids consumption after open gynecological surgery. However, they seem to decrease intraoperative opioids requirements and shorten emergence time. Nevertheless, these findings should be validating in further studies with large sample size.Introducción y objetivos del estudio: existe evidencia de que la administración perioperatoria de ketamina y lidocaína intravenosa reduce el dolor y el consumo de opioides postoperatorio, acorta la estancia hospitalaria y acelera la recuperación de la función intestinal. Sin embargo, no se han estudiado los efectos beneficiosos en el período intraoperatorio. El objetivo de este estudio fue evaluar el efecto de una única dosis de lidocaína y ketamina sobre el consumo intraoperatorio de opioides en pacientes sometidas a cirugía ginecológica electiva bajo anestesia general.
Material y métodos: estudio prospectivo, aleatorizado, doble ciego, controlado con placebo en un solo centro. Se incluyeron 33 pacientes (11 en el grupo ketamina, 11 en el grupo lidocaína y 11 en el grupo placebo). Para la analgesia postoperatoria se utilizó una bomba PCA (Analgesia Controlada por el Paciente ) de morfina. Los pacientes fueron asignados al azar a uno de los tres grupos de estudio: 1,5 mg/kg de lidocaína al 2%, 0,5 mg/kg de ketamina al 5% o solución salina 0.9%. La variable principal del estudio fue el consumo de opioides durante la cirugía. Las variables secundarias fueron: tiempo de educción de la anestesia, intensidad del dolor, consumo de opioides en las 24 horas posteriores a la cirugía y efectos adversos.
Resultados: se observó una disminución del consumo intraoperatorio de opioides en los grupos ketamina (402,3 ± 106,3) y lidocaína (397,7 ± 107,5) frente al grupo placebo (561,4 ± 97,1); p = 0,001. Se encontró una correlación positiva entre el consumo intraoperatorio de opioides y el tiempo de despertar (r = 0,864, p <0,001). No hubo diferencias significativas respecto a la intensidad del dolor en reposo en las 24 horas posteriores a la cirugía. El consumo total de morfina en las primeras 24 horas tras la cirugía no difirió significativamente entre los grupos (placebo: 27,54 ± 11,75; ketamina: 30,95 ± 7,88; lidocaína 34,77 ± 10,25; p = 0,26). Las náuseas y vómitos postoperatorios fueron más frecuentes en el grupo placebo (se observó en 3 pacientes del grupo ketamina, en 5 del grupo lidocaína y en 9 del grupo placebo; p = 0,027).
Conclusión: Nuestros resultados no apoyan el uso de una única dosis intraoperatoria de lidocaína o ketamina para disminuir el dolor postoperatorio y el consumo de opioides tras cirugía ginecológica abierta. Sin embargo, si parece disminuir los requerimientos intraoperatorios de opioides y acortar el tiempo de educción de la anestesia. No obstante, estos resultados deben ser validados en futuros estudios con mayor tamaño muestral
The Effect of Organization Restructuring on Organization Performance Viewed From Employee Performance and Leadership Effectiveness at Maluku Provincial Education Office
The focus of this research is to comprehensively analyze the effect of organization restructuring on the performance of the organization, directly or indirectly, involving 276 employees in the education office and the Ministry of Education and Culture offices and collected by survey method. Data analysis was done using causal correlation technique to see the effect of organization restructuring on organization performance. The results of the research indicate that there is a direct influence of organization restructuring on organization performance. Another result is that there is an indirect effect of restructuring through employee performance and leadership effectiveness on organization performance. The influence of organization performance improvement is due to, organization restructuring implemented in Maluku Province education office has lead to behavior change, where the employees of education office were able to improve individual performance and can work together with the leadership as an efficient and effective structure. This has an impact on improving organization performance
Effect of impurity substitution on band structure and mass renormalization of the correlated FeTeSe superconductor
Using angle-resolved photoemission spectroscopy (ARPES), we studied the
effect of the impurity potential on the electronic structure of
FeTeSe superconductor by substituting 10\% of Ni for Fe which
leads to an electron doping of the system. We could resolve three hole pockets
near the zone center and an electron pocket near the zone corner in the case of
FeTeSe, whereas only two hole pockets near the zone center and
an electron pocket near the zone corner are resolved in the case of
FeNiTeSe, suggesting that the hole pocket
having predominantly the orbital character is very sensitive to the
impurity scattering. Upon electron doping, the size of the hole pockets
decrease and the size of the electron pockets increase as compared to the host
compound. However, the observed changes in the size of the electron and hole
pockets are not consistent with the rigid-band model. Moreover, the effective
mass of the hole pockets is reduced near the zone center and of the electron
pockets is increased near the zone corner in the doped
FeNiTeSe as compared to FeTeSe.
We refer these observations to the changes of the spectral function due to the
effect of the impurity potential of the dopants.Comment: 8 pages, 3 figure
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