64 research outputs found
Fluktuációk és zajok alap- és interdiszciplináris kutatása fizikai, neurocardiológiai és nanotechnologiai szakterületeken = Basic and interdisciplinary research of noise and fluctuations in physics, neurocardiology and nanotechnology
A fluktuációkkal javított érzékelés alkalmazásához kis méretű és fogyasztású számítógépvezérelt műszereket fejlesztettünk, melyek segítségével megmutattuk, hogy szén nanocső alapú és más szenzorokon végzett zajspektroszkópiai mérések alkalmasak lehetnek különböző gáztípusok vagy akár baktériumok megkülönböztetésére. Digitális jelprocesszor alapú kísérleti eszközöket fejlesztettünk ki, melyekkel elsőként sikerült demonstrálnunk a termikus zajra épülő abszolút biztonságos kommunikáció működését valós rendszeren. Az excimer lézerek késleltetésének sztochasztikus jelek felhasználásán alapuló aktív szabályozásához kifejlesztett módszerünkhöz új hardvert terveztünk, mely hatékonyabb működést tesz lehetővé, additív zaj felhasználásával segíti a késleltetési idő detektálását. Algoritmusokat és szoftvereket fejlesztettünk ki főként ritmuszavar során fellépő EKG-jelek időtartománybeli és spektrális analíziséhez. Emellett vizsgáltuk, hogy az emberi agy hogyan képes a véletlenszerű jelekben elrejtett determinisztikus minták felismerésére és tanulására. Interdiszciplináris kutatási eredményeinkhez tartozik egy baktériumok fotoszintézisének mérésére tervezett számítógépvezérelt fluorométer és a kísérlezető oktatást támogató számos hardver és szoftver kifejlesztése is. A pályázat során megjelent 32 publikáció között szerepel 20 nemzetközi folyóiratcikk (összesített impakt faktor: 37,203), melyek 5 nemzetközi és egy hazai meghívott konferenciaelőadáshoz kötődnek. | We have built low-consumption, small-size computer-controlled devices for fluctuation-enhanced sensing. With these instruments we have shown that noise spectroscopy measurements of carbon nanotubes or other sensors can differentiate between gases or bacteria. We have developed digital signal processor-based experimental devices with which we could be the first to demonstrate the feasibility of thermal noise-driven totally secure communication in a real-world system. We have designed new methods and the associated hardware to enhance the efficiency of the active control of excimer laser delay by using additive noise to improve delay detection. We have developed algorithms and software for the time-domain and spectral analysis of ECG signals recorded mainly during arrhythmias. We have also studied the capacity of the human brain to recognise and learn deterministic patterns hidden in seemingly random signals. Our interdisciplinary results include a computer-controlled fluorimeter for measuring bacterial photosynthesis and several hardware and software developments to support teaching experiments
A hazai települések népességszám-változási problémái 1990-2019 között
Hungary is among the worst countries of the World in demographic view, it has low birth and high death rate, large natural increase of the population, but moderate migration gain. There are large differences at settlement level within the country. Between 1990 and 2011 among the settlements with the highest population increase there were almost entirely suburban villages and small towns. In the period of 2012-2019 the pattern is more diverse. Beside the suburban villages there are many other types (villages near the Ukrainian border, extreme small villages, touristic villages) among the fasters growing ones. The most interesting group is the villages with migration gain but really without migration. Especially neat the Ukrainian border the migrants make just addresses, but not migrate
Yggdrasil: a test question editor with symbolic expression support in high-throughput multi-language education
When preparing test questions for a large population of students,
one usually needs to reconcile two conflicting factors: on one
hand, the variability, and on the other hand, the consistent difficulty of questions. Random selection from a large pool of unrelated questions does ensure variability, but at the cost of comparable difficulty. One way to provide balanced difficulty is to create
templates with variants that may differ in numeric values or relevant phrases, or may simply employ negation. Experience shows
us, though, that manual variant management is as cumbersome
as it is error-prone. In this paper, we shall introduce a program
we wrote in C# to address this problem. The program, Yggdrasil,
supports the creation of templates with text-valued, logical or numeric symbolic expressions, manages their interdependence in
an internal context and produces an output where the expressions are replaced by individual variants. The templates are easy
to import into computer-assisted translation tools, allowing the
translation of the templates themselves instead of the high number of variants. At the moment, Yggdrasil can provide xml output
for the CooSpace learning management system used by the University of Szeged or LATEX files for a printable pdf, but to increase
availability, we plan to implement Word docx output
Yggdrasil: a test question editor with symbolic expression support in high-throughput multi-language education
A method based on light scattering to estimate the concentration of virus particles without the need for virus particle standards
Most often the determination of the concentration of virus particles is rendered difficult by the availability of proper standards. We have adapted a static light scattering based method for the quantification of virus particles (shown for poliovirus) without the need of virus particle standards. Instead, as standards, well-characterized polymeric nanoparticle solutions are used. The method is applicable for virus particles acting as Rayleigh scatterers, i.e., virus particles with equivalent diameters up to ca. 1/10th of the wavelength of the scattered monochromatic light (∼70 nm diameter). Further limitations may arise if the refractive index of the virus is unavailable or cannot be calculated based on its composition, such as in case of enveloped viruses. The method is especially relevant for preparation of virus particle concentration standards and to vaccine formulations based on attenuated or inactivated virus particles where the classical plaque forming assays cannot be applied. The method consists of:
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Measuring the intensity of the light scattered by viruses suspended in an aqueous solution.
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Measuring the intensity of the light scattered by polymeric nanoparticles of known concentration and comparable size with the investigated virus particle.
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The concentration of virus nanoparticles can be calculated based on the two measured scattered light intensities by knowing the refractive index of the dispersing solution, of the polymer and virus nanoparticles as well as their relative sphere equivalent diameters
Review of sound card photogates
Photogates are probably the most commonly used electronic instruments to aid
experiments in the field of mechanics. Although they are offered by many
manufacturers, they can be too expensive to be widely used in all classrooms,
in multiple experiments or even at a home experimentation. Today all computers
have a sound card - an interface for analogue signals. It is possible to make
very simple yet highly accurate photogates for cents, while much more
sophisticated solutions are also available at a still very low cost. In our
review we show several experimentally tested ways of implementing sound card
photogates in detail, and we also provide a full-featured, free, open-source
photogate software as a much more efficient experimentation tool than the
usually used sound recording programs. Further information is provided in a
dedicated page, www.noise.physx.u-szeged.hu/edudev
Transient Hypoperfusion to Ischemic/Anoxic Spreading Depolarization is Related to Autoregulatory Failure in the Rat Cerebral Cortex
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