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Search Results: 1 - 10 of 32368 matches for " Peter Kostic "
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Journal of Special Education and Rehabilitation , 2000,
Abstract: The main research objectives are the problems in the vocabulary of school aged, lightly mentally retarded children. Results of the research indicate which are the most important factors that have impact of the vocabulary and language competence of these persons. The research variables are: sex, IQ, chronological age and school age. Comics-like stories were used as an examination instrument in this research. Their interpretation is helpful in determining the vocabulary level of every single examine. At the end of the research some suggestions are presented, whose goal is to enrich children's vocabulary.
Analytical time-like geodesics
Uros Kostic
Physics , 2012, DOI: 10.1007/s10714-012-1328-5
Abstract: Time-like orbits in Schwarzschild space-time are presented and classified in a very transparent and straightforward way into four types. The analytical solutions to orbit, time, and proper time equations are given for all orbit types in the form r=r(\lambda), t=t(\chi), and \tau=\tau(\chi), where \lambda\ is the true anomaly and \chi\ is a parameter along the orbit. A very simple relation between \lambda\ and \chi\ is also shown. These solutions are very useful for modeling temporal evolution of transient phenomena near black holes since they are expressed with Jacobi elliptic functions and elliptic integrals, which can be calculated very efficiently and accurately.
Bijections Between Multiparking Functions, Dirichlet Configurations, and Descending R-Traversals
Dimitrije Kostic
Mathematics , 2006,
Abstract: There are several combinatorial objects that are known to be in bijection to the spanning trees of a graph G. These objects include G-parking functions, critical configurations of G, and descending traversals of G. In this paper, we extend the bijections to generalizations of all three objects.
Role of innate signalling pathways in the immunogenicity of alphaviral replicon-based vaccines
Tanja I N?slund, Linda Kostic, Eva KL Nordstr?m, Margaret Chen, Peter Liljestr?m
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-36
Abstract: We show that the induction of a CD8+ T cell response did not require functional TLR3 or MyD88 signalling. However, IRF3, converging several innate signalling pathways and important for generation of pro-inflammatory cytokines and type I IFNs, was needed for obtaining a robust primary immune response. Interestingly, type I interferon (IFN), induced by most innate signalling pathways, had a suppressing effect on both the primary and memory T cell responses after DREP and VREP immunization.We show that alphaviral replicon-based vectors activate multiple innate signalling pathways, which both activate and restrict the induced immune response. These results further show that there is a delicate balance in the strength of innate signalling and induction of adaptive immune responses that should be taken into consideration when innate signalling molecules, such as type I IFNs, are used as vaccine adjuvant.Alphaviral replicon-based vectors are attractive vaccine candidates since they induce strong immune responses in various animal models. The alphaviral replicon encodes an alphavirus replicase, an RNA polymerase, which strongly amplifies the replicon encoded transgene RNA resulting in high heterologous antigen production. Initially, the superior immune response induced by these types of vectors was attributed to abundant antigen production [1,2]. However, the replicase activity also leads to the formation of double stranded RNA (dsRNA), which induces activation and cross-priming of viral associated antigens in CD8α+ dendritic cells (DCs) [3]. Hence, it is now becoming increasingly clear that the immunogenicity of alphaviral replicon-based vectors is due to activation of innate immune responses, rather than increased antigen production.We have previously used alphaviral replicon-based vaccines administered as viral particles capable of one round of replication (VREPs) [4]. These VREPs, based on Semliki Forest virus (SFV), induce strong antibody and cellular responses in anim
Optimizing positive end-expiratory pressure by oscillatory mechanics minimizes tidal recruitment and distension: an experimental study in a lavage model of lung injury
Emanuela Zannin, Raffaele L Dellaca, Peter Kostic, Pasquale P Pompilio, Anders Larsson, Antonio Pedotti, Goran Hedenstierna, Peter Frykholm
Critical Care , 2012, DOI: 10.1186/cc11858
Abstract: We studied six pigs in which lung injury was induced by bronchoalveolar lavage. The animals were ventilated with a tidal volume of 6 ml/kg. Forced oscillations at 5 Hz were superimposed on the ventilation waveform. Pressure and flow were measured at the tip and at the inlet of the endotracheal tube respectively. Respiratory system reactance (Xrs) was computed from the pressure and flow signals and expressed in terms of oscillatory elastance (EX5). Positive end-expiratory pressure (PEEP) was increased from 0 to 24 cm H2O in steps of 4 cm H2O and subsequently decreased from 24 to 0 in steps of 2 cm H2O. At each PEEP step CT scans and EX5 were assessed at end-expiration and end-inspiration.During deflation the relationship between both end-expiratory and end-inspiratory EX5 and PEEP was a U-shaped curve with minimum values at PEEP = 13.4 ± 1.0 cm H2O (mean ± SD) and 13.0 ± 1.0 cm H2O respectively. EX5 was always higher at end-inspiration than at end-expiration, the difference between the average curves being minimal at 12 cm H2O. At this PEEP level, CT did not show any substantial sign of intra-tidal recruitment/derecruitment or expiratory lung collapse.Using FOT it was possible to measure EX5 both at end-expiration and at end-inspiration. The optimal PEEP strategy based on end-expiratory EX5 minimized intra-tidal recruitment/derecruitment as assessed by CT, and the concurrent attenuation of intra-tidal variations of EX5 suggests that it may also minimize tidal mechanical stress.Current strategies for mechanical ventilation of patients with acute respiratory distress syndrome (ARDS) include low tidal volumes and increased positive end-expiratory pressure (PEEP) [1]. The physiological basis for these strategies is still under debate, but may involve the reduction of forces of stress and strain on the parenchyma [2]. The ARDSNet protocol is a table-based approach of setting PEEP and the fraction of inspired oxygen (FIO2) levels to achieve an oxygenation target [3]. The a
Positive end-expiratory pressure optimization with forced oscillation technique reduces ventilator induced lung injury: a controlled experimental study in pigs with saline lavage lung injury
Peter Kostic, Emanuela Zannin, Marie Andersson Olerud, Pasquale P Pompilio, G?ran Hedenstierna, Antonio Pedotti, Anders Larsson, Peter Frykholm, Raffaele L Dellaca
Critical Care , 2011, DOI: 10.1186/cc10236
Abstract: 17 pigs, in which acute lung injury (ALI) was induced by saline lavage, were studied. Animals were randomized into two groups: in the first PEEP was titrated according to Xrs (FOT group), in the control group PEEP was set according to the ARDSNet protocol (ARDSNet group). The duration of the trial was 12 hours. In both groups recruitment maneuvers (RM) were performed every 2 hours, increasing PEEP to 20 cmH2O. In the FOT group PEEP was titrated by monitoring Xrs while PEEP was reduced from 20 cmH2O in steps of 2 cmH2O. PEEP was considered optimal at the step before which Xrs started to decrease. Ventilatory parameters, lung mechanics, blood gases and hemodynamic parameters were recorded hourly. Lung injury was evaluated by histopathological analysis.The PEEP levels set in the FOT group were significantly higher compared to those set in the ARDSNet group during the whole trial. These higher values of PEEP resulted in improved lung mechanics, reduced driving pressure, improved oxygenation, with a trend for higher PaCO2 and lower systemic and pulmonary pressure. After 12 hours of ventilation, histopathological analysis showed a significantly lower score of lung injury in the FOT group compared to the ARDSNet group.In a lavage model of lung injury a PEEP optimization strategy based on maximizing Xrs attenuated the signs of ventilator induced lung injury. The respiratory system reactance measured by FOT could thus be an important component in a strategy for delivering protective ventilation to patients with ARDS/acute lung injury.Mechanical ventilation is a mainstay of intensive care for patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). A ventilation strategy based on tidal volumes of 6 ml.kg-1 and pre-defined positive end-expiratory pressure (PEEP) settings has been shown to reduce morbidity and mortality probably due to less ventilation-induced lung injury (VILI) [1-3]. Various protocols using higher levels of PEEP in combination
Optics in the Schwarzschild space-time
Andrej Cadez,Uros Kostic
Physics , 2004, DOI: 10.1103/PhysRevD.72.104024
Abstract: Realistic modelling of radiation transfer in and from variable accretion disks around black holes requires the solution of the problem: find the constants of motion and equation of motion of a light-like geodesic connecting two arbitrary points in space. Here we give the complete solution of this problem in the Schwarzschild space-time.
Multiparking Functions, Graph Searching, and the Tutte Polynomial
Dimitrije Kostic,Catherine Yan
Mathematics , 2006,
Abstract: A parking function of length n is a sequence (b_1, b_2,..., b_n) of nonnegative integers whose nondecreasing rearrangement (a_1, a_2,...,a_n) has the property that a_i < i for every i. A well-known result about parking functions is that the polynomial P_n(q), which enumerates the complements of parking functions by the sum of their terms, is the generating function for the number of connected graphs by the number of excess edges when evaluated at (1+q). In this paper we extend this result to arbitrary connected graphs G. In general the polynomial that encodes information about subgraphs of G is the Tutte polynomial, which is the generating function for two parameters, namely the internal and external activities, associated with the spanning trees of G. We define G-multiparking functions, which generalize the G-parking functions that Postnikov and Shapiro introduced in the study of certain quotients of the polynomial ring. We construct a family of algorithmic bijections between the spanning forests of a graph G and the G-multiparking functions. In particular, the bijection induced by the breadth-first search leads to a new characterization of external activity, and hence a representation of Tutte polynomial by the reversed sum of G-multiparking functions.
Velimir Kostic,Marina Djordjevic,Lidija Popovic,Emina Kostic
Acta Medica Medianae , 2008,
Abstract: The presence of infections caused either by hepatitis B or C viruses or both of them complicates the evolution of chronic renal failure considerably.The aim of our investigation was to determine the presence of hepatotropic viral markers, clinical and laboratory characteristics, as well as therapeutic possibilities for examined patients.Our investigation included 136 patients who had had regular dialysis treatment. Based on the presence of viral markers, all the patients were divided in 3 groups: (I) HBV positive patients; (II) HCV positive patients, (III) HBV and HCV positive patients. All the patients were subdivided in two groups: those with an acute form and those with a chronic form based on the clinical course of the disease.The laboratory analysis did not show a clear correlation with the course of the disease, especially in those patients with a chronic disease. These finding allow us to draw the following conclusions: a significant number of patients have been infected with hepatitis B and C viruses; laboratory analysis in patients with a chronic course did not always correlate with the evolution of the disease; the clinical course is mostly mild.Introducing antiviral therapy gives a much better perspective to all categories of patients.
Mi?ko Zivic,Slavoljub Kostic
Acta Medica Medianae , 2000,
Abstract: The malign tumors of the nose and of the paranasal sinus are usuallyrecognized only at an advanced stage of the disease when the bone walls get erodedthus making a five years period of survival less than 50%. The lymph drainage isdirected towards the submandibular, parotid and jugudigastric lymph nodes. Such tumors rarely give netastases of the neck as well as distant ones; however, theirspawning to the surrounding vital structure of the head is frequent and it is the maincause of the lethal outcome. The most frequent tumor of the paranasal sinus is in themaxillary sinus followed by the one in the ethmoid labyrinth and the nose hollow.Regarding histology, the most frequent is the planocellular carcinoma (about 80%)while the other types are less frequent. Except in the initial stadium, the maligntumors of the para nasal sinuses are treated by the combined surgical andradiotherapy. The radical surgical intervention is first done later to be completed bythe radiotherapy. The time between the operation and the radiotherapy should bemaximally reduced due to the established bad results in the cases when this timeinterval was prolonged. The propagation in the skull base, the cavernous sinus, thepterygoid space, the nasopharynx and the inoperable neck nodes can be a relativccounterindication for the surgical trealment. Tn some cases it is necessary to add theenucleation of the orbit or the combined craniofacial approach for the sake ofremoving the tumor. The disease recessives, regardless of wherher the therapy wassurgical of radiotherapy, occur in the first two years.
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