Ramsauer approach for light scattering on non-absorbing spherical particles and application to the Henyey-Greenstein phase function

We present a new method to study light scattering on non-absorbing spherical particles. This method is based on the Ramsauer approach, a model known in atomic an nuclear physics. Its main advantage is its intuitive understanding of the underlying physics phenomena. We show that although the approximations are numerous, the Ramsauer analytical solutions describe fairly well the scattering phase function and the total cross section. Then this model is applied to the Henyey-Greenstein parameterisation of scattering phase function to give a relation between its asymmetry parameter and the mean particle size.Comment: 25 pages, 12 figures, journal paper, accepted in Applied Optics. arXiv admin note: text overlap with arXiv:0903.297

Postoperative delirium after major orthopedic surgery.

BACKGROUND: Postoperative delirium (POD) is one of the most common complications in older adult patients undergoing elective surgery. Few studies have compared, within the same institution, the type of surgery, risk factors and type of anesthesia and analgesia associated with the development of POD. AIM: To investigate the following three questions: (1) What is the incidence of POD after non-ambulatory orthopedic surgery at a high-volume orthopedic specialty hospital? (2) Does surgical procedure influence incidence of POD after non-ambulatory orthopedic surgery? And (3) For POD after non-ambulatory orthopedic surgery, what are modifiable risk factors? METHODS: A retrospective cohort study was conducted of all non-ambulatory orthopedic surgeries at a single orthopedic specialty hospital between 2009 and 2014. Patients under 18 years were excluded from the cohort. Patient characteristics and medical history were obtained from electronic medical records. Patients with POD were identified using International Classification of Diseases, 9th Revision (ICD-9) codes that were not present on admission. For incidence analyses, the cohort was grouped into total hip arthroplasty (THA), bilateral THA, total knee arthroplasty (TKA), bilateral TKA, spine fusion, other spine procedures, femur/pelvic fracture, and other procedures using ICD-9 codes. For descriptive and regression analyses, the cohort was grouped, using ICD-9 codes, into THA, TKA, spinal fusions, and all procedures. RESULTS: Of 78492 surgical inpatient surgeries, the incidence from 2009 to 2014 was 1.2% with 959 diagnosed with POD. The incidence of POD was higher in patients undergoing spinal fusions (3.3%) than for patients undergoing THA (0.8%); THA patients had the lowest incidence. Also, urgent and/or emergent procedures, defined by femoral and pelvic fractures, had the highest incidence of POD (7.2%) than all other procedures. General anesthesia was not seen as a significant risk factor for POD for any procedure type; however, IV patient-controlled analgesia was a significant risk factor for patients undergoing THA [Odds ratio (OR) = 1.98, 95% confidence interval (CI): 1.19 to 3.28, P = 0.008]. Significant risk factors for POD included advanced age (for THA, OR = 4.9, 95%CI: 3.0-7.9, P \u3c 0.001; for TKA, OR = 2.16, 95%CI: 1.58-2.94, P \u3c 0.001), American Society of Anesthesiologists score of 3 or higher (for THA, OR = 2.01, 95%CI: 1.33-3.05, P \u3c 0.001), multiple medical comorbidities, hyponatremia (for THA, OR = 2.36, 95%CI: 1.54 to 3.64, P \u3c 0.001), parenteral diazepam (for THA, OR = 5.05, 95%CI: 1.5-16.97, P = 0.009; for TKA, OR = 4.40, 95%CI: 1.52-12.75, P = 0.007; for spine fusion, OR = 2.17, 95%CI: 1.19-3.97, P = 0.01), chronic opioid dependence (for THA, OR = 7.11, 95%CI: 3.26-15.51, P \u3c 0.001; for TKA, OR = 2.98, 95%CI: 1.38-6.41, P = 0.005) and alcohol dependence (for THA, OR = 5.05, 95%CI: 2.72-9.37, P \u3c 0.001; for TKA, OR = 6.40, 95%CI: 4.00-10.26, P \u3c 0.001; for spine fusion, OR = 6.64, 95%CI: 3.72-11.85, P \u3c 0.001). CONCLUSION: POD is lower (1.2%) than previously reported; likely due to the use of multi-modal regional anesthesia and early ambulation. Both fixed and modifiable factors are identified

From Creativity to Responsible Createlligence® as Future Competence

Distinguished colleagues, ladies and gentlemen, it is a great honour and pleasure for me to talk to you today, a special day since it is my birthday, a special day since you have invited me to share my ideas and visions with you, all educational experts from quite a different region of the world, compared to that where I come from. But it is mostly relevant and necessary to exchange ideas and expertise, since what we are learning more and more today is that the world is a global village, that we all are connected into global systems, that we all together are children of that one and only mother earth, and only together can survive and develop

Automated Reasoning and Presentation Support for Formalizing Mathematics in Mizar

This paper presents a combination of several automated reasoning and proof presentation tools with the Mizar system for formalization of mathematics. The combination forms an online service called MizAR, similar to the SystemOnTPTP service for first-order automated reasoning. The main differences to SystemOnTPTP are the use of the Mizar language that is oriented towards human mathematicians (rather than the pure first-order logic used in SystemOnTPTP), and setting the service in the context of the large Mizar Mathematical Library of previous theorems,definitions, and proofs (rather than the isolated problems that are solved in SystemOnTPTP). These differences poses new challenges and new opportunities for automated reasoning and for proof presentation tools. This paper describes the overall structure of MizAR, and presents the automated reasoning systems and proof presentation tools that are combined to make MizAR a useful mathematical service.Comment: To appear in 10th International Conference on. Artificial Intelligence and Symbolic Computation AISC 201

A Survey of the Occupational, Community Living, and Leisure Time Strengths and Weaknesses of Trainable Mentally Retarded Adults

All human beings have a right to become all that they can be, whether that potential leads to great discoveries in the sciences or is limited to learning how to dress oneself. Seeking new techniques and methods to help each child reach his full potential is a challenge to every professional in special education

Do Lognormal Column-Density Distributions in Molecular Clouds Imply Supersonic Turbulence?

Recent observations of column densities in molecular clouds find lognormal distributions with power-law high-density tails. These results are often interpreted as indications that supersonic turbulence dominates the dynamics of the observed clouds. We calculate and present the column-density distributions of three clouds, modeled with very different techniques, none of which is dominated by supersonic turbulence. The first star-forming cloud is simulated using smoothed particle hydrodynamics (SPH); in this case gravity, opposed only by thermal-pressure forces, drives the evolution. The second cloud is magnetically subcritical with subsonic turbulence, simulated using nonideal MHD; in this case the evolution is due to gravitationally-driven ambipolar diffusion. The third cloud is isothermal, self-gravitating, and has a smooth density distribution analytically approximated with a uniform inner region and an r^-2 profile at larger radii. We show that in all three cases the column-density distributions are lognormal. Power-law tails develop only at late times (or, in the case of the smooth analytic profile, for strongly centrally concentrated configurations), when gravity dominates all opposing forces. It therefore follows that lognormal column-density distributions are generic features of diverse model clouds, and should not be interpreted as being a consequence of supersonic turbulence.Comment: 6 pages, 6 figures, accepted for publication in MNRA

Validation and Optimization of Ptera Software: An Open-Source Unsteady Simulator for Flapping Wings

Scientists have long used the unsteady vortex lattice method (UVLM) to simulate flapping-wing flight. However, there are few open-source UVLM solvers designed for research in this field. The newly released Ptera Software is, to the best of the authors’ knowledge, the only open-source UVLM solver for flapping wings that is in active development. This report documents the next steps in Ptera Software’s progress: the validation of its results and the optimization of its performance. Comparing Ptera Software’s output to high-fidelity experimental data of the pressures on a flapping-wing robot shows that the simulated results predict the trends and magnitudes of the net lift over time with reasonable accuracy. Also, by using several computational methods, the researchers optimized the source code such that the solver’s latest iteration is over three times faster than previous versions. The present results demonstrate that Ptera Software correctly implements the UVLM and can simulate flapping-wing flight with reasonable accuracy under this method’s assumptions. Additionally, it is now fast enough for use as an iterative tool in the design of novel flapping-wing micro aerial vehicles (FWMAVs)