Modeling of SAR signatures of shallow water ocean topography

A hydrodynamic/electromagnetic model was developed to explain and quantify the relationship between the SEASAT synthetic aperture radar (SAR) observed signatures and the bottom topography of the ocean in the English Channel region of the North Sea. The model uses environmental data and radar system parameters as inputs and predicts SAR-observed backscatter changes over topographic changes in the ocean floor. The model results compare favorably with the actual SEASAT SAR observed backscatter values. The developed model is valid for only relatively shallow water areas (i.e., less than 50 meters in depth) and suggests that for bottom features to be visible on SAR imagery, a moderate to high velocity current and a moderate wind must be present

Some Good Reasons to Use Matched Filters for the Detection of Point Sources in CMB Maps

In this draft we comment on the results concerning the performances of matched filters, scale adaptive filters and Mexican hat wavelet that recently appeared in literature in the context of point source detection in Cosmic Microwave Background maps. In particular, we show that, contrary to what has been claimed, the use of the matched filters still appear to be the most reliable and efficient method to disantangle point sources from the backgrounds, even when using detection criterion that, differently from the classic $n\sigma$ thresholding rule, takes into account not only the height of the peaks in the signal corresponding to the candidate sources but also their curvature.Comment: Replacement after submission to A&A and referee's comments. Astronomy and Astrophysics, in press, JNL/2003/473

Közösségi tanulás és társadalmi átalakulás. Két alföldi „tanuló város” példája

A vonatkozó irodalom (Longworth, 1999, 2006; Glaeser, 1999; Carillo, 2012 stb.) szerint a „tanuló régió, tanuló város, tanuló közösség” az élethosszig tanulás új megjelenési formája. Glaeser (1999) úgy érvel, hogy „az egyének egymással interakcióban szereznek készségeket, és a sűrűn lakott városi környezet fölgyorsítja ezeket az interakciókat”. Jelen tanulmány szerzői a „tanulást” tágabb értelemben használják: tanuló közösségek azok, amelyek a társadalmi-gazdasági kihívásokra innovatív válaszokat tudnak adni. A szerzők a „tanuló városok” új értelmezését alakítják ki, amely szerint az ilyen városok (a) szembenéznek a társadalmi-gazdasági kihívással, (b) innovatív válaszokat tudnak adni rájuk, és (c) kialakítják az erről szóló narratívát, amelyet tovább is adnak közösségük nemzedékeinek. A szerzők két magyarországi kisváros párhuzamos példáján illusztrálják, menynyire alkalmazható a „tanuló városnak” ez az általuk kialakított új értelmezése. Mindkét városnak szembe kellett néznie az 1989/90-es rendszerváltozással. De csak egyikük bizonyult „tanuló városnak”, amennyiben sikeres és innovatív válaszokat tudott adni a politikai rendszerváltozás társadalmi-gazdasági kihívásaira

Menekülés az iskolától

After the enthusiasm of 1989/90 (the political transition in Hungary), the local schools has runned by the local authorities. The grass-rooted decentralisation, however, ended up in growing tensions between the local and the central educational authorities. After the 2010 parliamentary and local elections, the government implemented a massive centralisation policy, offering “opting out” possibility for every local authority who became unable to finance its own school any more. Why do the local governments (having been enthusiastic before) want to give back their institutions today? And why do the teachers protest against the recentralisation process? Telling the story of recentralisation in a Hungarian town, the authors discover a new power sharing between the local authorities and the teacher organisations. Teachers became more and more influential (informal power) in the local society so they were able to limit the educational policy decisions of the local government. The loss of power ended up with financial crisis of the schools. The authors suggest that decentralisation and recentralisation are complementary policies, and both of them has to be applied to balance the growing costs of education

Visszapillantó

Az 1970-es évek oktatáspolitikai történéseit részben egy hosszan készülődő tantervi reform uralta, részben pedig az úgynevezett strukturális reform (Báthory, 2001). Kétségtelenül az előbbi volt a látványosabb. Az 1972-es párthatározat nyitva hagyta az utat a kísérletezések előtt; sőt egyenesen bátorította is őket. Nyomában megelevenedett az iskolai kísérletező kedv. De ezek a kísérletezések csupán a látványelemeket jelentették. (1

Death talk: gender differences in talking about one's own impending death.

To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.According to common practice based on a generally agreed interpretation of Icelandic law on the rights of patients, health care professionals cannot discuss prognosis and treatment with a patient's family without that patient's consent. This limitation poses ethical problems, because research has shown that, in the absence of insight and communication regarding a patient's impending death, patient's significant others may subsequently experience long-term psychological distress. It is also reportedly important for most dying patients to know that health care personnel are comfortable with talking about death and dying. There is only very limited information concerning gender differences regarding death talk in terminal care patients.This is a retrospective analysis of detailed prospective "field notes" from chaplain interviews of all patients aged 30-75 years receiving palliative care and/or with DNR (do not resuscitate) written on their charts who requested an interview with a hospital chaplain during a period of 3 years. After all study patients had died, these notes were analyzed to assess the prevalence of patient-initiated discussions regarding their own impending death and whether non-provocative evocation-type interventions had facilitated such communication.During the 3-year study period, 195 interviews (114 men, 81 women) were conducted. According to the field notes, 80% of women and 30% of men initiated death talk within the planned 30-minute interviews. After evoking interventions, 59% (67/114) of men and 91% (74/81) of women engaged in death talk. Even with these interventions, at the end of the first interview gender differences were still statistically significant (p = 0.001). By the end of the second interview gender difference was less, but still statistically significant (p = 0.001).Gender differences in terminal care communication may be radically reduced by using simple evocation methods that are relatively unpretentious, but require considerable clinical training.Men in terminal care are more reluctant than women to enter into discussion regarding their own impending death in clinical settings. Intervention based on non-provocative evocation methods may increase death talk in both genders, the relative increase being higher for men.National University Hospital Icelandic Centre for Research (RANNIS), Iceland Stockholm County Council, Health Services, Swede

Consensus formation on coevolving networks: groups' formation and structure

We study the effect of adaptivity on a social model of opinion dynamics and consensus formation. We analyze how the adaptivity of the network of contacts between agents to the underlying social dynamics affects the size and topological properties of groups and the convergence time to the stable final state. We find that, while on static networks these properties are determined by percolation phenomena, on adaptive networks the rewiring process leads to different behaviors: Adaptive rewiring fosters group formation by enhancing communication between agents of similar opinion, though it also makes possible the division of clusters. We show how the convergence time is determined by the characteristic time of link rearrangement. We finally investigate how the adaptivity yields nontrivial correlations between the internal topology and the size of the groups of agreeing agents.Comment: 10 pages, 3 figures,to appear in a special proceedings issue of J. Phys. A covering the "Complex Networks: from Biology to Information Technology" conference (Pula, Italy, 2007

Synchronization in Weighted Uncorrelated Complex Networks in a Noisy Environment: Optimization and Connections with Transport Efficiency

Motivated by synchronization problems in noisy environments, we study the Edwards-Wilkinson process on weighted uncorrelated scale-free networks. We consider a specific form of the weights, where the strength (and the associated cost) of a link is proportional to $(k_{i}k_{j})^{\beta}$ with $k_{i}$ and $k_{j}$ being the degrees of the nodes connected by the link. Subject to the constraint that the total network cost is fixed, we find that in the mean-field approximation on uncorrelated scale-free graphs, synchronization is optimal at $\beta^{*}$$=$-1. Numerical results, based on exact numerical diagonalization of the corresponding network Laplacian, confirm the mean-field results, with small corrections to the optimal value of $\beta^{*}$. Employing our recent connections between the Edwards-Wilkinson process and resistor networks, and some well-known connections between random walks and resistor networks, we also pursue a naturally related problem of optimizing performance in queue-limited communication networks utilizing local weighted routing schemes.Comment: Papers on related research can be found at http://www.rpi.edu/~korniss/Research