Variational principles and the shift in the front speed due to a cutoff

We apply variational principles to reaction-diffusion equations in order to predict, for a general reaction term, the sign of the shift in the front speed due to a cutoff. We develop an improved variational principle to obtain the shift in the front speed for a wide range of reaction terms, and the theoretical results so obtained are in excellent agreement with numerical solutions. This work proves that variational principles are an optimal framework to deal with fronts propagating into unstable and metastable states under cutoff

Distribution of the S-matrix in chaotic microwave cavities with direct processes and absorption

We quantify the presence of direct processes in the S-matrix of chaotic microwave cavities with absorption in the one-channel case. To this end the full distribution P_S(S) of the S-matrix, i.e. S=\sqrt{R}e^{i\theta}, is studied in cavities with time-reversal symmetry for different antenna coupling strengths T_a or direct processes. The experimental results are compared with random-matrix calculations and with numerical simulations based on the Heidelberg approach including absorption. The theoretical result is a generalization of the Poisson kernel. The experimental and the numerical distributions are in excellent agreement with random-matrix predictions for all cases.Comment: 4 pages, 4 figure

Segregation and pursuit waves in activator-inhibitor systems

We investigate the effects of cross-diffusion on propagating waves in an activator-inhibitor system. The model consists of a piecewise linear approximation of FitzHugh-Nagumo kinetics and a cross-diffusion term for either the activator or the inhibitor. We obtain exact analytic solutions for traveling fronts and solitary pulses and discuss the corresponding speed diagrams. A detailed comparison with the corresponding Rinzel-Keller model for the usually studied case of self-diffusion is performed

Publicaciones médicas: ¿ciencia o negocio?

En los últimos años ha aumentado enormemente el número de revistas científicas, de tal manera que hoy día es imposible leer ni siquiera el 1% de lo que se publica sobre nuestra especialidad o sobre los campos que nos interesen. La proliferación de revistas científicas en general y en el campo de la Medicina en especial puede ser debido a muchas razones. Entre ellas destacan, en nuestra opinión, la aparición de Internet y el cambio de la razón de ser de las publicaciones científicas. Comentaremos en esta revisión las razones que han llevado a este hecho.Sociedad Canaria de Osteoporosis (2016)

Applications of Direct Injection Soft Chemical Ionisation-Mass Spectrometry for the Detection of Pre-blast Smokeless Powder Organic Additives

Analysis of smokeless powders is of interest from forensics and security perspectives. This article reports the detection of smokeless powder organic additives (in their pre-detonation condition), namely the stabiliser diphenylamine and its derivatives 2-nitrodiphenylamine and 4-nitrodiphenylamine, and the additives (used both as stabilisers and plasticisers) methyl centralite and ethyl centralite, by means of swab sampling followed by thermal desorption and direct injection soft chemical ionisation-mass spectrometry. Investigations on the product ions resulting from the reactions of the reagent ions H3O+ and O2+ with additives as a function of reduced electric field are reported. The method was comprehensively evaluated in terms of linearity, sensitivity and precision. For H3O+, the limits of detection (LoD) are in the range of 41-88 pg of additive, for which the accuracy varied between 1.5 and 3.2%, precision varied between 3.7 and 7.3% and linearity showed R20.9991. For O2+, LoD are in the range of 72 to 1.4 ng, with an accuracy of between 2.8 and 4.9% and a precision between 4.5 and 8.6% and R20.9914. The validated methodology was applied to the analysis of commercial pre-blast gun powders from different manufacturers.(VLID)4826148Accepted versio

Visual vs auditory augmented reality for indoor guidance

Indoor navigation systems are not widely used due to the lack of effective indoor tracking technology. Augmented Reality (AR) is a natural medium for presenting information in indoor navigation tools. However, augmenting the environment with visual stimuli may not always be the most appropriate method to guide users, e.g., when they are performing some other visual task or they suffer from visual impairments. This paper presents an AR app to support visual and auditory stimuli that we have developed for indoor guidance. A study (N=20) confirms that the participants reached the target when using two types of stimuli, visual and auditory. The AR visual stimuli outperformed the auditory stimuli in terms of time and overall distance travelled. However, the auditory stimuli forced the participants to pay more attention, and this resulted in better memorization of the route. These performance outcomes were independent of gender and age. Therefore, in addition to being easy to use, auditory stimuli promote route retention and show potential in situations in which vision cannot be used as the primary sensory channel or when spatial memory retention is important. We also found that perceived physical and mental efforts affect the subjective perception about the AR guidance app

Noise Mitigation Strategies in Smart Cities

Noise mitigation strategies in Smart Citie

Técnica de Imhäuser en el pie zambo : resultados a medio y largo plazo

Se revisan un total de 60 pies con equinovaro congénito pertenecientes a 48 pacientes, todos con un seguimiento superior a 5 años. En todos los casos se realizó un tratamiento combinado: ortopédico (manipulaciones y enyesados desde el nacimiento) y quirúrgico (correcciones según el método de Imhäuser modificado). Se valoró morfológica, funcional y radiográficamente cada caso. En la valoración global sólo 1 caso fue considerado malo, 13 regulares (21,6%), 6 por pies planos valgos, 3 por pronato de antepié y 4 por adducto de antepié, y 12 buenos (20%), aunque presentaban alguna alteración morfológica o funcional mínima, y 34 excelentes (56,6%). Se concluye que: 1) la técnica de Imhäuser ofrece en este trabajo el 77% de excelentes y buenos resultados; 2) el 2.° y 3.cr se pueden resumir en uno solo, el hemitrasplante del tibial anterior, y 3) los resultados clínicos, morfológicos y funcionales son superiores a los radiográficos.—We cheked 42 patients with club-feet (60 feet), all of them with follow-up over 5 years. All the patients received a mixed treatment: orthopaedic (manipulation and plastering) and surgical (Imhäuser technique modified). We evaluated morphological, functional and radiographic parameters. In the overall evaluation only one of the cases was considered bad result; 13 (21.6%) fair results, 6 with valgus flat feet, 3 with pronatus forefoot and 4 with adductus forefoot; 12 (20%) good results, with a minimal morphologic or functional alterations; 34 (56.6%) were excellents results. Conclutions: 1) Imhäuser technic had 77% of good or excellent results in this work; 2) the second and third Imhäuser surgical times can be summarized in only one: the external hemitrasplant of the tibial anterior tendon, and 3) clinics, morphologics and functional results are better than radiographics results

Long-term outcomes after prophylactic use of onlay mesh in midline laparotomy.

Background The prevalence of incisional hernias (IHs) is still high after midline laparotomy (ML). There is an increasing body of evidence that prophylactic mesh placement (PMP) can be safe and efficient in the short-term outcomes, but there still are some concerns about the potential long-term complications of these meshes. This study describes our long-term PMP experience. Methods Observational and prospective study including all patients undergoing the use of prophylactic onlay large-pore polypropylene meshes for the closure of ML since 2008 to 2014. Outcome measures included demographics, perioperative details, wound complications, recurrences, reoperations and chronic complications. Results A cohort of 172 patients was analysed: 75% elective surgery, 25% emergency cases. Mean age was 68 years with mean body mass index (BMI) of 28.6 kg/m2. Wound classification: 6.4% clean; 85% clean-contaminated; 1.2% contaminated and 8.1% dirty. Follow-up of patients was up to 8 years (mean: 5 ± 1.6). Two meshes were removed due to chronic infection in first six postoperative months. Of the 13 patients (9.02%) who developed IH, 5 of them have been reoperated for IH repair without any difficulty related to previous mesh. During follow-up, 8 patients have been reoperated for other reasons and the integrity of abdominal wall was also checked. After the comparative study, higher BMI and emergency surgery were still risk factors for IH despite PMP. Conclusions In our setting, the use of polypropylene prophylactic meshes in MLs is safe, efficient and durable.pre-print977 K