Inversion of Airborne Contaminants in a Regional Model

We are interested in a DDDAS problem of localization of airborne contaminant releases in regional atmospheric transport models from sparse observations. Given measurements of the contaminant over an observation window at a small number of points in space, and a velocity field as predicted for example by a mesoscopic weather model, we seek an estimate of the state of the contaminant at the beginning of the observation interval that minimizes the least squares misfit between measured and predicted contaminant field, subject to the convection-diffusion equation for the contaminant. Once the ''initial'' conditions are estimated by solution of the inverse problem, we issue predictions of the evolution of the contaminant, the observation window is advanced in time, and the process repeated to issue a new prediction, in the style of 4D-Var. We design an appropriate numerical strategy that exploits the spectral structure of the inverse operator, and leads to efficient and accurate resolution of the inverse problem. Numerical experiments verify that high resolution inversion can be carried out rapidly for a well-resolved terrain model of the greater Los Angeles area

Quantum-mechanical model for particles carrying electric charge and magnetic flux in two dimensions

We propose a simple quantum mechanical equation for $n$ particles in two dimensions, each particle carrying electric charge and magnetic flux. Such particles appear in (2+1)-dimensional Chern-Simons field theories as charged vortex soliton solutions, where the ratio of charge to flux is a constant independent of the specific solution. As an approximation, the charge-flux interaction is described here by the Aharonov-Bohm potential, and the charge-charge interaction by the Coulomb one. The equation for two particles, one with charge and flux ($q, \Phi/Z$) and the other with ($-Zq, -\Phi$) where $Z$ is a pure number is studied in detail. The bound state problem is solved exactly for arbitrary $q$ and $\Phi$ when $Z>0$. The scattering problem is exactly solved in parabolic coordinates in special cases when $q\Phi/2\pi\hbar c$ takes integers or half integers. In both cases the cross sections obtained are rather different from that for pure Coulomb scattering.Comment: 12 pages, REVTeX, no figur

Small incision cochlear implantation in children

Objective: Small incision cochlear implant surgery in children has been advocated to reduce post-operative morbidity and have a psychological effect on parents. With small incision techniques, it is not always possible to securely fix the device in place. This risks displacement of the device, particularly in active children. This technique has been used through minimal-access approach in children.Methods: Among 80 cochlear implantations in children performed between January 2003 and December 2010, there were 32 cases with very thin cortical bone in which small incision cochlear implant surgery were performed. As drill - hole fixation methods can carry the potential for dural injury we have used the suture fixation through the cranial periosteum. This method shortened the surgical time and there were no specific postoperative complications. Results: One complication has occurred related to the current technique (maximum follow up 30 months). No flap necrosis, hematoma or infection, nor extrusion or breakdown was encountered with either technique. Revision surgery was performed in 2 patients (1 with small incision due to posttraumatic device failure) and one due to cholesteatoma. The use of this minimally invasive surgical technique did not increase the surgical risk. Conclusion: Cochlear implantation can be performed using small incisions with periosteal sutures of the receiver. The described approach therefore appears to be a safe and time-effective alternative to the standard procedure in cochlear implant surgery

Posterior cordomtomy for bilateral vocal cord paralysis: CO2 laser vs. microsurgery with cold instruments

Idea: The restoration of the airways after bilateral vocal cord paralysis is still a challenge for the otolaryngologist. Techniques including endoscopic approaches (Kashima's technique) have been developed for management of adduction bilateral vocal cord paralysis. Method: From 1998 to 2011, 20 patients were endoscopically treated by CO2 Laser (15 patients) and by cold microsurgical instruments (5 patients) in our ENT Department. A better and simpler procedure is cordotomy using the Kashima technique. This involves separating one vocal cord from the vocal process, creating a posterior gap for respiration and maintaining anterior vocal cord contact for phonation.Results: The aetiology of vocal cord paralysis of our patients was the following: posttyroidectomy (8), central nervous system disease (7), idiopathic (5). All treatments were performed in one stage, except for one patient who underwent three month after operation a contralateral cordotomy. Post-operative assessment was performed and consisted of videolaryngoscopy with 70 degree rigid endoscope. The respiratory function and the phonation presented the similar results in both techniques. The healing process was delayed in cases of microsurgery with cold instruments. Speech therapy is used to supplement the operation.Conclusion: Our experience suggests that bilateral vocal cord paralysis can be primarily treated by posterior cordotomy. Moreover, the different therapeutic choices should be adjusted by the surgeon for the patient's gender, age, general conditions, physical and professional activities

Upper airway obstruction determined by a mixed laryngocele - Literature review - About 2 cases treated in ENT Department Timisoara

Introduction: We reviewed the treatment options for laryngoceles over the last two decades.Methods: We searched PubMed for the keyword "laryngocele", assessing the type of laryngocele/laryngopyocele (internal/external) and the treatment modality. Results: We identified 71 laryngoceles in 63 patients, assessing the surgical treatment. An external approach was performed in 25 of 29 (86.2%) cases of mixed laryngoceles. In our ENT Department Timisoara we identified in the last 2 decades a number of 5 cases, and the last 2 cases presented a mixed laryngoceles with respiratory distress.Conclusions: CO2 LASER resection by microlaryngoscopy represents the main therapeutic option for internal laryngoceles while the external approaches still remain the main therapeutic approach for the treatment of mixed laryngoceles.Der Erstautor gibt keinen Interessenkonflikt an

On molecular orientability on a fine porous surface

The refraction of a porous structure with adsorbed molecules was investigated. Effects based on adsorbate molecule orientability relative to the whole porous sample were evidenced including quantitative estimates of the adsorbate molecule amount in pores. In a resonance electromagnetic field, sharp changes in the permeability of a fine-pored sample were observed corresponding to a variation in the incident laser intensity. Finally, a theory of the orientational action of the radiation field was developed, which accounts for the adsorption potential increase not only by the interaction of field polarized molecules with those on the surface, but also by the interaction of the induced molecular dipole with its reflection in the wall material.Le sujet de cette recherche concerne l'étude de la réfraction d'une structure poreuse contenant des molécules adsorbées. Nous avons mis en évidence des effets liés à l'orientabilité des molécules adsorbées par rapport a l'échantillon poreux. Nous donnons également une estimation de la quantité de molécules adsorbées dans les pores. Dans un champ électromagnétique résonnant, nous avons observé une modification sensible de la perméabilité d'une membrane finement poreuse. Ces modifications correspondent à une variation de l'intensité laser incidente. Nous avons enfin développé une théorie de l'action d'orientation du champ de radiation. Cette théorie explique l'accroissement du potentiel d'adsorption dû d'une part, à l'interaction des molécules polarisées par le champ avec les molécules de la surface, d'autre part à l'interaction du dipôle moléculaire induit avec son image dans la paroi de l'échantillon