Sample records for taavi toomela rasmus
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Molenaar, Peter C M
2007-03-01
I am in general agreement with Toomela's (Integrative Psychological and Behavioral Science doi:10.1007/s12124-007-9004-0, 2007) plea for an alternative psychological methodology inspired by his description of the German-Austrian orientation. I will argue, however, that this alternative methodology has to be based on the classical ergodic theorems, using state-of-the-art statistical time series analysis of intra-individual variation as its main tool. Some more specific points made by Toomela will be criticized, while for others a more extreme elaboration along the lines indicated by Toomela is proposed.
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Has 60 years of research in psychology really gone astray?
Yurevich, Andrey
2007-03-01
The author presents several arguments against Toomela's (Culture of science: Strange history of the methodological thinking in psychology. Integrative Psychological and Behavioral Science, 2007a, doi:10.1007/sl2124-007-9004-0, History of methodology in psychology: Starting point, not the goal. Integrative Psychological and Behavioral Science, 2007b, doi:10.1007/sl2124-007-9005-z) pessimistic thesis: "The last 60 years of research in psychology seems to have gone astray." Nevertheless he admits that Toomela's article despite the excessively categorical assessments contained in it and the undue pessimism crowing its conclusion, represents a substantial contribution to the highlighting of socio-cultural impact on various models of psychological cognition, which lurks behind the international unification of globalizing science.
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Conradi, Lenard; Seiffert, Moritz; Shimamura, Kazuo; Schirmer, Johannes; Blankenberg, Stefan; Reichenspurner, Hermann; Diemert, Patrick; Treede, Hendrik
2014-09-01
Transcatheter aortic valve implantation (TAVI) has become routine for the treatment of high-risk patients with aortic stenosis. We assessed safety and feasibility of a left ventricular apical access and closure device combined with second-generation transapical (TA) TAVI transcatheter heart valves (THV). Three elderly, comorbid patients (logEuroSCORE I 13.0-31.1%) received transapical aortic valve implantation (TA-AVI) via the Apica ASC device (Apica Cardiovascular Ltd., Galway, Ireland) using second-generation THV (Medtronic Engager [Medtronic 3F Therapeutics, Santa Ana, California, United States], JenaValve [JenaValve Technology GmbH, Munich, Germany], Symetis Acurate [Symetis S.A., Ecublens, Switzerland]). Access was gained using a non-rib-spreading technique and a novel access and closure device. THV deployment was successful with excellent hemodynamic outcome (no PVL, n = 2; trace PVL, n = 1; mean transvalvular gradients, 5-19 mm Hg) and complete apical hemostasis. No periprocedural major adverse events occurred and Valve Academic Research Consortium-2-defined composite end point of device success was met in all cases. Safety and feasibility of TA-AVI using the ASC device with second-generation THV was demonstrated. Combining latest available technology is a major step toward improved functional outcome and decreased surgical trauma in TA-AVI. Potentially, technical enhancements may eventually pave the way toward a fully percutaneous TA-AVI procedure. Georg Thieme Verlag KG Stuttgart · New York.
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Czerwinska, Katarzyna; Orłowska-Baranowska, Ewa; Witkowski, Adam; Demkow, Marcin; Abramczuk, Elżbieta; Michałek, Piotr; Greszata, Lidia; Stoklosa, Patrycjusz; Kuśmierski, Krzysztof; Kowal, Jaroslaw; Stepinska, Janina
2011-01-01
Surgical aortic valve replacement (AVR) still remains the treatment of choice in symptomatic significant aortic stenosis (AS). Due to technical problems, extensive calcification of the ascending aorta (“porcelain aorta”) is an additional risk factor for surgery and transapical aortic valve implantation (TAAVI) is likely to be the only rescue procedure for this group of patients. We describe the case of an 81-year-old woman with severe AS and “porcelain aorta”, in whom the only available life-saving intervention was TAAVI. PMID:22295040
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The SOURCE Registry: what is the learning curve in trans-apical aortic valve implantation?
Wendler, Olaf; Walther, Thomas; Schroefel, Holger; Lange, Rüdiger; Treede, Hendrik; Fusari, Melissa; Rubino, Paolo; Thomas, Martyn
2011-06-01
Trans-apical aortic valve implantation (TA-AVI) has been shown to be a reproducible technique. Early results from the SAPIEN Aortic Bioprosthesis European Outcome (SOURCE) Registry identified major access complications associated with high 30-day mortality. Using the SOURCE Registry, we analyze the learning curve for TA-AVI over the first 2 years after commercialization. The SOURCE Registry gathered data for 2 consecutive years at European centers following commercialization of the Edwards SAPIEN bioprosthesis, totaling 2339 patients (1038 in COHORT 1 and 1301 in COHORT 2). Only data from centers that provided all of their consecutively treated patients were included in this study. We compared the 30-day results of TA-AVI from COHORT 1 (C-1: January/2008-January/2009) with the 30-day results of COHORT 2 (C-2: February/2009-January/2010). This analysis is based on a total number of 575 TA-AVIs in C-1 and 819 TA-AVIs in C-2. Mean age (C-1: 80.7 years, C-2: 80.5 years) and logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) (C-1: 29.1%, C-2 27.3%) were not significantly different. Valve malposition (C-1: 1.6%, C-2: 1.2%), valve migration/embolization (C-1: 0.5%, C-2: 1.0%), and major access complications (C-1: 2.1%, C-2: 1.8%) were in total less frequent, but not statistically significant lower in C-2. However, the reduction of aortic regurgitation >2+ immediately following the procedure (C-1: 4.52%, C-2: 2.1%, p=0.011) and conversion rate to open surgery (C-1: 3.7%, C-2: 1.5%, p=0.0315) reached statistical significance. Postoperative complications included dialysis (C-1: 7.0%, C-2: 5.7%, p=ns), pacemaker implantation (C-2: 7.7%, C-2: 6.7%, p=ns), stroke (C-1: 2.4%, C-2: 2.6%, p=ns), and myocardial infarct (C-1: 0.7%, C-2: 0.4%, p=ns). The total 30-day mortality was 10.8% and not significantly different between the two groups (C-1: 10.8%, C-2: 10.7%, p=ns). Although the incidence of technical intra procedural complications has trended downward
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Separated Representations and Fast Algorithms for Materials Science
2007-10-29
Quantum Chemisty , 127 (1999), pp. 143–269. [28] A. Smilde, R. Bro, and P. Geladi, Multi-way Analysis. Applications in the Chemical Sciences, John...Advances in highly correlated approaches. Advances in Quantum Chemisty , 127:143–269, 1999. [58] Age Smilde, Rasmus Bro, and Paul Geladi. Multi-way Analysis
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Transcatheter aortic valve implantation transapical: step by step.
Walther, Thomas; Möllmann, Helge; van Linden, Arnaud; Kempfert, Jörg
2011-01-01
Transcatheter aortic valve implantation (T-AVI) has been introduced into clinical practice to treat high-risk elderly patients with aortic stenosis. T-AVI can be performed by using a retrograde transfemoral (TF), transsubclavian, transaortic, and/or antegrade transapical (TA) approach. For TA-AVI, CE mark approval was granted in 2008 for the Edwards SAPIEN (Edwards Lifesciences, Irvine, CA) prosthesis with the Ascendra delivery system and in 2010 for the second-generation Edwards SAPIEN XT prosthesis and the Ascendra II delivery system, with 23-mm and 26-mm valves. In 2011, CE mark approval has been granted for TA-AVI by using the SAPIEN XT 29-mm prosthesis. Several other devices from different companies (Jenavalve, Jena Valve Inc, Munich, Germany; Embracer, Medtronic Inc, Guilford, CT; Accurate, Symetis Inc, Geneva, Switzerland) have passed "first in man trials" successfully and are being evaluated within multicenter pivotal studies. In this article we will focus on specific aspects of the TA technique for AVI. Copyright © 2011 Elsevier Inc. All rights reserved.
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Möllmann, Helge; Bestehorn, Kurt; Bestehorn, Maike; Papoutsis, Konstantinos; Fleck, Eckart; Ertl, Georg; Kuck, Karl-Heinz; Hamm, Christian
2016-06-01
Transvascular (TV-AVI) or transapical (TA-AVI) aortic valve implantation (TAVI) is a treatment option for patients with aortic stenosis being at high or prohibitive risk for surgical aortic valve implantation (SAVR). Randomized data demonstrated that these subgroups can safely been treated with TAVI. However, a comparison of SAVR and TAVI in intermediate and low-risk patients is missing. Therefore, the aim of the analysis was to compare TAVI and SAVR in all patients who were treated for aortic valve stenosis in Germany throughout 1 year. The mandatory quality assurance collects data on the in-hospital outcome from all patients (n = 20,340) undergoing either SAVR or TAVI in Germany. In order to compare the different treatment approaches patients were categorized into four risk groups using the logistic EuroScore I (ES). In-hospital mortality and peri- and postprocedural complications were analyzed. The in-hospital mortality did not differ between TV-AVI and SAVR in the low risk group (ES <10 %: TV-AVI 2.4 %, SAVR 2.0 %, p = 0.302) and was significantly higher for SAVR in all other risk groups (ES 10-20 %: TV-AVI 3.5 %, SAVR 5.3 %; p = 0.025; ES 20-30 %: TV-AVI 5.5 %, SAVR 12.2 %, p < 0.001; ES >30 %: TV-AVI 6.5 %, SAVR 12.9 %, p = 0.008). TA-AVI had a significantly higher mortality in all risk groups compared to TV-AVI. In comparison to SAVR, TA-AVI had a higher mortality in patients with ES <10, comparable mortality in ES 10-20 %, and lower mortality in patients with an ES >20 %. The overall stroke rate was 2.3 %. It occurred more frequently in patients with an ES <10 % treated with a transapical approach (SAVR 1.8 %, TV-AVI 1.9 %, TA-AVI 3.1 %, p < 0.01). There were no statistically significant differences in all other comparisons. This study demonstrates that TAVI provides excellent outcomes in all risk categories. Compared with SAVR, TV-TAVI yields similar in-hospital mortality among low-risk patients and lower in
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Walther, Thomas; Thielmann, Matthias; Kempfert, Joerg; Schroefel, Holger; Wimmer-Greinecker, Gerhard; Treede, Hendrik; Wahlers, Thorsten; Wendler, Olaf
2013-05-01
The study aimed to evaluate 1-year outcomes of the multicentre PREVAIL transapical (TA) study of TA-aortic valve implantation (AVI) in high-risk patients. From September 2009 to August 2010, a total of 150 patients, aged 81.6 ± 5.8 years, 40.7% female, were included at 12 European TA-AVI experienced sites. Patients received 23 (n = 36), 26 (n = 57) and 29 mm (n = 57) second-generation SAPIEN XT™ (Edwards Lifesciences, Irvine, CA, USA) valves. The mean logistic EuroSCORE was 24.3 ± 7.0, and mean Society Thoracic Surgeons score was 7.5 ± 4.4%. Survival was 91.3% at 30 days and 77.9% at 1 year. Subgroup analysis revealed survivals of 91.7/88.9, 86.0/70.2, 96.55/91.2% for patients receiving 23-, 26- and 29-mm valves at 30 days and at 1 year, respectively. Transthoracic echocardiography revealed preserved left ventricular ejection fraction and low gradients. Aortic incompetence was none in 41/48, trace 30/36, mild 22/12 and moderate in 7/4% at discharge and 1 year. Walking distance increased from 221 (postimplant) to 284 m (at 1 year, P = 0.0004). Three patients required reoperation due to increasing aortic incompetence during follow-up. Causes of mortality at 1 year were cardiac (n = 7), stroke (n = 1) and others (n = 5). The European PREVAIL multicentre trial demonstrates good functionality and good outcomes for TA-AVI using the second-generation SAPIEN XT prosthesis and the ASCENDRA-II delivery system. The 29-mm SAPIEN XT valve was successfully introduced and showed excellent results.
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Walther, Thomas; Thielmann, Matthias; Kempfert, Joerg; Schroefel, Holger; Wimmer-Greinecker, Gerhard; Treede, Hendrik; Wahlers, Thorsten; Wendler, Olaf
2012-08-01
Transapical (TA) aortic valve implantation (AVI) has evolved as an alternative procedure for high-risk patients. We evaluated the second-generation SAPIEN XT™ prosthesis in a prospective multicentre clinical trial. A total of 150 patients (age: 81.6 ± 5.8 years; 40.7% female) were included. Prosthetic valves (diameter: 23 mm (n = 36), 26 mm (n = 57) and 29 mm (n = 57)) were implanted. The ASCENDRA-II™ modified delivery system was used in the smaller sizes. Mean logistic EuroSCORE was 24.3 ± 7.0%, and mean STS score 7.5 ± 4.4%. All patients gave written informed consent. Off-pump AVI was performed using femoral arterial and venous access wires as a safety net. All but two patients received TA-AVI, as planned. The 29-mm valve showed similar function as the values of two other diameters did. Three patients (2%) required temporary cardiopulmonary bypass support. Postoperative complications included renal failure requiring long-term dialysis in four, bleeding requiring rethoracotomy in four, respiratory complication requiring reintubation in eight and sepsis in four patients, respectively. Thirty-day mortality was 13 (8.7%) for the total cohort and 2/57 (3.5%) for patients receiving the 29-mm valve, respectively. Echocardiography at discharge showed none or trivial aortic incompetence (AI) in 71% and mild-AI in 22% of the patients. Post-implantation AI was predominantly paravalvular and ≥ 2+ in 7% of patients. One patient required reoperation for AI within 30 days. The PREVAIL TA multicentre trial demonstrates good functionality and good outcomes for TA-AVI, using the SAPIEN XT™ prosthesis and its second-generation ASCENDRA-II™ delivery system, as well successful introduction of the 29-mm SAPIEN XT™ valve for the benefit of high-risk elderly patients.
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A second prosthesis as a procedural rescue option in trans-apical aortic valve implantation.
Kempfert, Jörg; Rastan, Ardawan J; Schuler, Gerhard; Linke, Axel; Holzhey, David; van Linden, Arnaud; Mohr, Friedrich-W; Walther, Thomas
2011-07-01
Trans-apical aortic valve implantation (TA-AVI) using the Edwards SAPIEN™ prosthesis has evolved to a routine procedure for selected high-risk elderly patients. In rare cases, misplacement of the SAPIEN™ valve (too low a position), dysfunction of the leaflets or perforation of the interventricular septum (ventricular septal defect, VSD) occurs and requires immediate implantation of a second prosthesis within the first one. Results of this 'bailout' maneuver have not been reported yet. Of 305 TA-AVI procedures, 15 patients required a second prosthesis due to dysfunctional leaflets (n = 6), low position (n = 7), or VSD (n = 2). Mean age was 82.5 ± 1.3 years, mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 45.5 ± 5.4, and Society of Thoracic Surgeons (STS) Score was 13.5 ± 1.5. All second SAPIEN™ valves could be implanted successfully within the first one. The second prosthesis solved leaflet dysfunction, sealed the VSD (lower position of the second prosthesis), or corrected the initial misplacement (higher position of the second prosthesis) in all patients. Within 30 days, four patients died (low cardiac output n = 3, all with preoperative ejection fraction (EF) <35%; intestinal ischemia n = 1). Intra-operative echocardiogram and angiogram revealed mild paravalvular leak in three and none/trace in 12 patients. Transvalvular gradients were low despite the implantation of the second valve (P(max)/mean 13.7 ± 4.3/6.4 ± 2.0). Placement of a second SAPIEN™ valve is a valuable 'bailout' technique in case of VSD, dysfunctional leaflets, or too low placement of the first prosthesis. The technique leads to an excellent functional result with low transvalvular gradients. The simple, straight, tubular stent design of the SAPIEN™ prosthesis may be the ideal design for such valve-in-valve procedures. Copyright © 2011 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.
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A Protective Factors Model for Alcohol Abuse and Suicide Prevention among Alaska Native Youth
Allen, James; Mohatt, Gerald V.; Fok, Carlotta Ching Ting; Henry, David; Burkett, Rebekah
2014-01-01
This study provides an empirical test of a culturally grounded theoretical model for prevention of alcohol abuse and suicide risk with Alaska Native youth, using a promising set of culturally appropriate measures for the study of the process of change and outcome. This model is derived from qualitative work that generated an heuristic model of protective factors from alcohol (Allen at al., 2006; Mohatt, Hazel et al., 2004; Mohatt, Rasmus et al., 2004). Participants included 413 rural Alaska Native youth ages 12-18 who assisted in testing a predictive model of Reasons for Life and Reflective Processes about alcohol abuse consequences as co-occurring outcomes. Specific individual, family, peer, and community level protective factor variables predicted these outcomes. Results suggest prominent roles for these predictor variables as intermediate prevention strategy target variables in a theoretical model for a multilevel intervention. The model guides understanding of underlying change processes in an intervention to increase the ultimate outcome variables of Reasons for Life and Reflective Processes regarding the consequences of alcohol abuse. PMID:24952249
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Method for in-vivo synthetic aperture B-flow imaging
NASA Astrophysics Data System (ADS)
Jensen, Jorgen A.
2004-04-01
B-flow techniques introduced in commercial scanners have been useful is visualizing places of flow. The method is relatively independent of flow angle and can give a good perception of vessel location and turbulence. This paper introduces a technique for making a synthetic aperture B-flow system. Data is acquired over a number of pulse emissions, where a set of elements synthesizes a spherical wave and the received signal on all elements are acquired. The sequence is repeated and a full new image can always be formed from the last set of emissions, thus making the frame rate very high. The data is continuously available at all places in the image and any kind of echo canceling filter can therefore be used without the usual initialization problems. The B-flow images are then formed by displaying the gray level image after echo canceling. A fast moving scatterer will give a bright echo and slower moving scatterers will yield a dark echo. The approach is demonstrated through in-vivo images. A 128 elements 7 MHz probe with lambda pitch is used together with the RASMUS experimental scanner. Eleven elements are used per emission and the eight emissions are spread evenly over the 128 elements of the array. The signal received by the 64 elements closets to the emission are sampled at 40 MHz and 12 bits at a pulse repetition frequency of 3 kHz. A full second of data is acquired from a healthy 29 years old male volunteer from the carotid artery. The data is beamformed, combined, and echo canceled off-line. High-pass filters designed by the Remez exchange algorithm, have been used for the B-flow processing. The image is displayed after each set of emissions yielding 375 frames per second. Both the flow in the carotid artery and the jugular vein can be seen along with an indication of the acceleration and spatial variation of the velocity.
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Directional synthetic aperture flow imaging.
Jensen, Jørgen Arendt; Nikolov, Svetoslav Ivanov
2004-09-01
A method for flow estimation using synthetic aperture imaging and focusing along the flow direction is presented. The method can find the correct velocity magnitude for any flow angle, and full color flow images can be measured using only 32 to 128 pulse emissions. The approach uses spherical wave emissions with a number of defocused elements and a linear frequency-modulated pulse (chirp) to improve the signal-to-noise ratio. The received signals are dynamically focused along the flow direction and these signals are used in a cross-correlation estimator for finding the velocity magnitude. The flow angle is manually determined from the B-mode image. The approach can be used for both tissue and blood velocity determination. The approach was investigated using both simulations and a flow system with a laminar flow. The flow profile was measured with a commercial 7.5 MHz linear array transducer. A plastic tube with an internal diameter of 17 mm was used with an EcoWatt 1 pump generating a laminar, stationary flow. The velocity profile was measured for flow angles of 90 and 60 degrees. The RASMUS research scanner was used for acquiring radio frequency (RF) data from 128 elements of the array, using 8 emissions with 11 elements in each emission. A 20-micros chirp was used during emission. The RF data were subsequently beamformed off-line and stationary echo canceling was performed. The 60-degree flow with a peak velocity of 0.15 m/s was determined using 16 groups of 8 emissions, and the relative standard deviation was 0.36% (0.65 mm/s). Using the same setup for purely transverse flow gave a standard deviation of 1.2% (2.1 mm/s). Variation of the different parameters revealed the sensitivity to number of lines, angle deviations, length of correlation interval, and sampling interval. An in vivo image of the carotid artery and jugular vein of a healthy 29-year-old volunteer was acquired. A full color flow image using only 128 emissions could be made with a high
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Trans-apical aortic valve implantation using a new self-expandable bioprosthesis: initial outcomes.
Kempfert, Jörg; Rastan, Ardawan J; Beyersdorf, Friedhelm; Schönburg, Markus; Schuler, Gerhard; Sorg, Stefan; Mohr, Friedrich-W; Walther, Thomas
2011-11-01
Trans-apical aortic valve implantation (TA-AVI) has evolved into a standard approach for high-risk, elderly patients using the balloon-expandable Edwards SAPIEN™ prosthesis. As an alternative device, a self-expanding sub-coronary trans-apical bioprosthesis was evaluated. The Symetis Acurate™ trans-catheter heart valve is composed of a porcine biologic valve attached to a self-expandable nitinol stent. It allows for anatomical orientation, and facilitates intuitive implantation providing tactile feedback. Three valves sizes were available to treat patients with an annular diameter between 21 and 27mm. Since November 2009, a total of 40 patients have been treated at three sites. Patient age was 82.8±4 years, 60% were female, logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 21.5±10.9% and Society of Thoracic Surgeons (STS) Score was 9.0±4.6%. All implants were delivered successfully in the intra-annular and sub-coronary position off pump. One patient was converted to conventional surgery due to coronary impingement; post-dilatation was performed in 45% of patients; and two patients required the SAPIEN™ valve in valve implantation. Echocardiographic and angiographic control revealed no/trivial aortic incompetence (AI) in 59%, mild AI in 33.3%, and moderate AI in 7.7% of the patients. Three patients died within 30 days from a non-valve-related cause (respiratory), the patient converted did not recover from right-heart failure, and one patient died on day 19 due to unclear reasons. There was one incidence of new-onset atrioventricular (AV) block requiring pacemaker implantation. Two patients suffered a stroke (one secondary and the other intraprocedural). Transvalvular gradients were maximum 29.4±10.7mmHg and mean 14.3±6.8mmHg. The initial clinical results indicate a relatively straightforward implantation procedure and good functional results after trans-apical implantation of the Symetis Acurate™ device. Copyright © 2011
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Naftz, D.L.; See, R.B.; Ramirez, P.
1993-01-01
The major tributaries draining the Kendrick Reclamation Project (KRP) account for an average of 52% of the total Se load measured in the North Platte River downstream from Casper, Wyoming. The Casper Creek drainage basin contributed the largest Se load of the five tributary sites to the North Platte River. The 4-d average Se concentration in water samples from one site in the part of the North Platte River that receives irrigation return flows exceeded the 5 ??g/l U.S. Environmental Protection Agency's aquatic life criterion five time during a 50-d monitoring period in 1989. In agreement with the water-quality data, muscle and liver tissue rom rainbow trout collected from the same part of the North Platte River had Se concentrations exceeding levels known to cause reproductive failure and chronic Se poisoning. On the basis of Se: Cl, 18O/16O and D/H ratios in water from Goose and Rasmus Lee Lakes (closed-basin systems), the large Se concentrations in those lakes were derived by natural evaporation of irrigation water without leaching of soluble forms of Se from soil or rocks. Water samples from Thirtythree Mile Reservoir and Illco Pond (flow-through systems) showed considerable enrichment in Se over evaporative concentration, presumably due to leaching and desorption of Se from soil and rock. The Se: Cl ratios of irrigation drain water collected from the KRP indicate that leaching and desorption of soluble forms of Se from soils and rocks are the dominant processes in drain water. Results of a Wilcoxon matched-pairs test for 43 paired drain-water samples collected during June and August 1988, indicated there is a statistically larger concentration of Se (0.01 significance level) during the June sampling period. The larger concentrations of Se and other chemical constitutents during the early part of the irrigation season probably were due to dissolution of seleniferous salts that have accumulated in soils within the KRP since the last irrigation season. The large
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NASA Astrophysics Data System (ADS)
Oana, Catrina; Parding, Kajsa Maria; Stefan, Sabina
2017-04-01
The importance of knowledge on the trajectories that Mediterranean cyclones follows toward Romania is fundamental because most of the times the weather phenomena that accompany them determine significant economic damage and not only. In the specialized literature, the principal classic trajectories on which the Mediterranean cyclones pass toward the south-east of Europe and by default toward Romania, causing in these areas a crucial weather conditions change in all aspects at any time during the year, have been determined in subjectively mode, many years ago, by C. Sorodoc (1962) E. I. Bordei (1983). Starting from the known 9 classic trajectories determined subjectively, in this study it was aimed and subsequently carried out their identification by this date, but objectively, using the method based on mathematic algorithms developed by Rasmus E. Benestad, Abdelkader Mezghani, and Kajsa M. Parding (2006). The study was carried out between January 2003 and December 2015, taking into account the fact that the presence of the Mediterranean cyclones may be established almost every month, these representing important links of the atmosphere movement over Europe. The data used by the daily review have contained values, in grid points, of the mean pressure field at sea level (MSLP), with spatial resolution of 0.75° x 0.75° and 6 hours temporal coverage, originating from ECMWF, ERA-Interim project (2006), and the chosen field of interest was between 15°W - 40°E and 30°N - 50°N. Of the total number of Mediterranean cyclones identified objectively, that followed trajectories toward Romania, were randomly selected only a few cases, which indicates the similarity between the paths of classic subjectively determined and those determined objectively. Validation of the results consisted in the first phase in a comparison between the trajectories identified with the classic trajectories determined subjectively, then was carried out a second validation, by analysis of the
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Possible Progenitor of Special Supernova Type Detected
NASA Astrophysics Data System (ADS)
2008-04-01
Using data from NASA's Chandra X-ray Observatory, scientists have reported the possible detection of a binary star system that was later destroyed in a supernova explosion. The new method they used provides great future promise for finding the detailed origin of these important cosmic events. In an article appearing in the February 14th issue of the journal Nature, Rasmus Voss of the Max Planck Institute for Extraterrestrial Physics in Germany and Gijs Nelemans of Radboud University in the Netherlands searched Chandra images for evidence of a much sought after, but as yet unobserved binary system - one that was about to go supernova. Near the position of a recently detected supernova, they discovered an object in Chandra images taken more than four years before the explosion. Optical image of SN 2007on Optical image of SN 2007on The supernova, known as SN 2007on, was identified as a Type Ia supernova. Astronomers generally agree that Type Ia supernovas are produced by the explosion of a white dwarf star in a binary star system. However, the exact configuration and trigger for the explosion is unclear. Is the explosion caused by a collision between two white dwarfs, or because a white dwarf became unstable by pulling too much material off a companion star? Answering such questions is a high priority because Type Ia supernovas are major sources of iron in the Universe. Also, because of their nearly uniform intrinsic brightness, Type Ia supernova are used as important tools by scientists to study the nature of dark energy and other cosmological issues. People Who Read This Also Read... Oldest Known Objects Are Surprisingly Immature Black Holes Have Simple Feeding Habits Discovery of Most Recent Supernova in Our Galaxy Geriatric Pulsar Still Kicking "Right now these supernovas are used as black boxes to measure distances and derive the rate of expansion of the universe," said Nelemans. "What we're trying to do is look inside the box." If the supernova explosion is
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EDITORIAL: Focus on Plasmonics FOCUS ON PLASMONICS
NASA Astrophysics Data System (ADS)
Bozhevolnyi, Sergey; García-Vidal, Francisco
2008-10-01
, Zhengtong Liu, Hsiao-Kuan Yuan, Rasmus H Pedersen, Alexandra Boltasseva, Jiji Chen, Joseph Irudayaraj, Alexander V Kildishev and Vladimir M Shalaev Confinement and propagation characteristics of subwavelength plasmonic modes R F Oulton, G Bartal, D F P Pile and X Zhang Theory on the scattering of light and surface plasmon polaritons by arrays of holes and dimples in a metal film F de León-Pérez, G Brucoli, F J García-Vidal and L Martín-Moreno Shaping and manipulation of light fields with bottom-up plasmonic structures C Girard, E Dujardin, G Baffou and R Quidant Gold nanorods and nanospheroids for enhancing spontaneous emission A Mohammadi, V Sandoghdar and M Agio Generation of surface plasmons at single subwavelength slits: from slit to ridge plasmon J-Y Laluet, A Drezet, C Genet and T W Ebbesen Mode mapping of plasmonic stars using TPL microscopy P Ghenuche, S Cherukulappurath and R Quidant Controlling optical transmission through magneto-plasmonic crystals with an external magnetic field G A Wurtz, W Hendren, R Pollard, R Atkinson, L Le Guyader, A Kirilyuk, Th Rasing, I I Smolyaninov and A V Zayats Nanoplasmonic renormalization and enhancement of Coulomb interactions M Durach, A Rusina, V I Klimov and M I Stockman Bulk and surface sensitivities of surface plasmon waveguides Pierre Berini Mapping plasmons in nanoantennas via cathodoluminescence R Gómez-Medina, N Yamamoto, M Nakano and F J García de Abajo Theoretical analysis of gold nano-strip gap plasmon resonators T Søndergaard, J Jung, S I Bozhevolnyi and G Della Valle Surface plasmon polariton-mediated enhancement of the emission of dye molecules on metallic gratings J Gómez Rivas, G Vecchi and V Giannini Nanoshells to nanoeggs to nanocups: optical properties of reduced symmetry core-shell nanoparticles beyond the quasistatic limit Mark W Knight and Naomi J Halas Single emitters coupled to plasmonic nano-antennas: angular emission and collection efficiency T H Taminiau, F D Stefani and N F van Hulst Green