531 research outputs found
Media and Democracy: Prospects and Problems
Eleanor Clift is a contributing editor for Newsweek and a panelist on The McLaughlin Group. Tom Brazaitis is the Washington senior editor for the Cleveland Plain Dealer. This is a lightly-edited transcription of their talk at a Sacred Heart University Public Forum on July 24, 2003, as Visiting Woodrow Wilson Fellows
In vivo and in vitro studies of positive allosteric modulation of the NMDA receptor
Dysfunction of the N-methyl-D-aspartate (NMDA) receptor is thought to contribute to the cognitive deficits of many neurodegenerative diseases and psychiatric disorders. Cognitive symptoms of Alzheimer’s disease can be treated with NMDA receptor antagonists or drugs targeting the cholinergic system; however, there are no effective treatments for cognitive deficits of schizophrenia or Huntington’s disease. With the discovery of a potent and selective allosteric modulator of the NMDA receptor, there is the possibility of new treatments based on NMDA receptor functional-enhancement through neuroactive steroids, closely related in structure to the endogenous neurosteroid, cerebrosterol. The aim of this thesis was to examine steroidal modulation of the NMDA receptor both in vitro and in vivo. In chapter 2, NMDA receptor enhancement of both the synthetic and endogenous neuroactive steroids was assessed in neurons maintained in cell culture using calcium imaging techniques. Sulphation of the steroids greatly increased the efficacy of NMDA receptor enhancement compared to the unsulphated steroids. Chapters 3 and 4 investigate the potential for neuroactive steroids to treat cognitive impairments of Huntington’s disease. Using a mouse model, tests were selected that were analogous to those in which patients are impaired; however, no impairments were found in the mouse model. Chapter 5, therefore, used a different model of cognitive impairment – namely, rats with a set-shifting impairment, as is seen in many psychiatric and neurological disorders, including Huntington’s disease – to assess the effect of the synthetic steroid administration. Unfortunately, the rats did not show the expected impairment. The lack of reliable animal models compromised testing the efficacy of these promising NMDA receptor positive allosteric modulators. Nevertheless, the promising in vitro results suggest that there could still be therapeutic potential. In addition, the compound is a useful research tool for exploring NMDA receptor function in health and disease.Thesis funded by MSD Scottish Life Sciences Fund and the Scottish Universities Life Allianc
Volumetric modelling of economic index structures
Economic index structures perform very important role in economy management and especially in process of preparing instant decisions. Therefore, timely and reasoned decision making and consequences of their implementation often depends on rationality of such structures. Volumetric model of economic index files, its development and adaptation are described in this article. This mathematical model allows to choose rational structure of particular index file, to evaluate it and to use it in practice gaining particular benefits. Specific example of model appliance is presented.Tūrinis ekonominių rodiklių struktūrų modeliavimasTatjana Brazaitienė, Zenonas Brazaitis
SummaryEkonominių rodiklių struktūros atlieka labai svarbų vaidmenį ūkio valdyme ir ypač – skubiai rengiant sprendimus. Todėl nuo tų struktūrų racionalumo labai dažnai priklauso pagrįstų sprendimų priėmimas laiku ir jų įgyvendinimo rezultatai. Straipsnyje aprašomas tūrinis ekonominių rodiklių rinkmenų modelis, jo kūrimas ir adaptavimas. Šis matematinis modelis leidžia išrinkti racionalią konkretaus rodiklio rinkmenos struktūrą, ją įvertinti ir taikyti gaunant tam tikrą naudą. Pateikiamos rodiklių rinkmenos dalies apimties matematinės vilties ir dispersijos skaičiavimo formulės, taip pat parodomi skaičiavimai visiems galimiems rinkmenos skaidymo būdams. Pateikiamas konkretus modelio naudojimo pavyzdys
Spontaneous Hybridization between Pinus mugo and Pinus sylvestris at the Lithuanian Seaside: A Morphological Survey
We address the problem of spontaneous hybridization between an exotic species Pinus mugo and the native/local P. sylvestris at the seaside spit of Kursiu Nerija in Lithuania. The objective was to identify spontaneous hybrids between P. mugo and P. sylvestris based on morphology traits among the individuals naturally regenerating at the seaside spit. The field inventory was carried out over the entire Lithuanian part of the spit, and 200 individuals morphologically intermediate between P. sylvestris and P. mugo were identified. Based on a weighted trait index, the intermediate individuals were grouped into two groups, one morphologically close to P. sylvestris and another close to P. mugo. The needle micromorphological traits of the putative hybrids were of intermediate values between P. mugo and P. sylvestris. The results provide a strong evidence of spontaneous hybridization between P. mugo and P. sylvestris in Lithuanian seaside spit of Kursiu Nerija
Informacinių sistemų dinaminio valdymo modeliavimas
Straipsnis skirtas informacinių sistemų (IS) valdymo modeliavimui, kai tam yra naudojami dalykinės srities grafai ir išoriniai duomenys. Modulinės struktūros IS valdymas naudojant išorinius duomenis siejamas su modulių grafais ir baigtiniu automatu, o vartotojų kreipimaisi į informacinę sistemą – su jų laisvosios formos keitimu fiksuotąja forma.Pateikiami informatyvūs sudaryto dviejų dalių IS dinaminio valdymo modelio taikymo pavyzdžiai sprendžiant konkrečius funkcinius verslo vadybos uždavinius.Pagrindiniai žodžiai: informacinė sistema, dalykinės srities grafas, išoriniai valdymo duomenys, modelis, baigtinis automatas.Dynamic control modelling of information systemsTatjana Brazaitienė, Zenonas Brazaitis
SummaryThe article addresses the control modelling of information systems (IS) by employing data having the structure of linear dynamic lists. Control through external data is related to finite automata, when the functions or actions of an information system depend on automata status, and status transition is controlled by signals which are symbols of free format queries into IS. A model of free format query change by a fixed format is analysed. A specific example of the model application is given, provided for solving the task of business management (material movement accounting).ight: 18px;"
Effect of Lower Body Compression Garments on Hemodynamics in Response to Running Session
Purpose. Compression garments are often worn during exercise and allegedly have ergogenic and/or physiological effects. In this study, we compared hemodynamics and running performance while wearing compression and loose-fit breeches. We hypothesized that in neutral-warm environment compression breeches impair performance by diminishing body cooling via evaporative sweat loss and redistributing blood from active musculature to skin leading to a larger rise in body temperature and prolonging recovery of hemodynamics after exercise. Methods. Changes in hemodynamics (leg blood flow, heart rate, and blood pressure during orthoclinostatic test), calf muscle tissue oxygenation, and skin and core temperatures were measured in response to 30 min running (simulation of aerobic training session) followed by maximal 400 m sprint (evaluation of running performance) in recreationally active females (25.1±4.2 yrs; 63.0±8.6 kg) wearing compression or loose-fit breeches in randomized fashion. Results. Wearing compression breeches resulted in larger skin temperature rise under the garment during exercise and recovery (by about 1°C, P<0.05; statistical power > 85%), while core temperature dynamics and other measured parameters including circulation, running performance, and sensations were similar compared to wearing loose-fit breeches (P>0.05). Conclusion. Compared with loose-fit breeches, compression breeches have neither positive nor negative physiological and performance effects for females running in thermoneutral environment
Fire Occurrence in Hemi-Boreal Forests: Exploring Natural and Cultural Scots Pine Fire Regimes Using Dendrochronology in Lithuania
Fire is an important natural disturbance and a driver of hemi-boreal forest successional trajectories, structural complexity, and biodiversity. Understanding the historic fire regime is an important step towards sustainable forest management. Focusing on Lithuania's hemi-boreal forests, we first mapped the potential natural fire regimes based on the relationship between site conditions, vegetation, and fire frequency using the ASIO model. The ASIO model revealed that all the fire frequency categories (Absent, Seldom, Intermittent, Often) are found in Lithuania. Scots pine forests dominated the often fire frequency category (92%). Secondly, focusing on a fire-prone forest landscape, Dzukija, we analyzed the fire occurrence of Scots pine forest types using dendrochronological records. We sampled and cross-dated 132 Scots pine samples with fire scars from four dry forest stands (n = 92) and four peatland forest stands (n = 40), respectively. In total, the fire history analysis revealed 455 fire scars and 213 fire events during the period of 1742-2019. The Weibull median fire intervals were 2.7 years (range 1-34) for the dry forest types and 6.3 years (range 1-27) for the peatland forest types. Analysis pre- and post-1950 showed the Weibull median fire interval increased from 2.2 to 7.2 for the dry forest types but decreased from 6.2 to 5.2. for the peatland forest types. A superposed epoch analysis revealed significant precipitation fluxes prior to the fire events after 1950. Thus, the Dzukija landscape of Lithuania has been strongly shaped by both human and naturally induced fires. The combination of theory (the ASIO model) with the examination of biological archives can be used to help guide sustainable forest management to emulate forest disturbances related to fire. As traditional forest management focusing on wood production has eliminated fire, and effectively simplified forest ecosystems, we recommend introducing educational programs to communicate the benefits and history of forest fires as well as adaptive management trials that use low-intensity prescribed burning of Scots pine stands
Predictors of Patellofemoral Pain Applying Full Weight Bearing Kinematic MRI
Purpose. To determine the associations among PFM, trochlea groove morphology, femoral and patellar rotation and to determine which measures best predict patellofemoral pain (PFP). Material & Methods. Knees of 51 female patients with PFP and 26 healthy female volunteers as control group were analysed with kinematic magnetic resonance imaging and full weight-bearing. The bisect offset (BSO), patellar tilt angle (PTA), femoral rotation angle (FRA), patellar rotation angle (PRA) were measured in steps of 10° between 0° to 50° of knee flexion. Static measures of Insall-Salvati ratio (ISR), sulcus angle (SAB & SAC) and lateral trochlear inclination at bone and cartilage levels (LTIB & LTIC) were performed and compared. Results. The SAB & SAC were higher and the LTIB & LTIC were lower in patients compared to volunteers. BSO, PTA, PRA and medial FRA were higher in the PFP group at all flexion angles. A multiple logistic regression analysis demonstrated that increase of FRA and SAB by 1° increased the likelihood of PFP 5.6 times and 1.6 times respectively, decrease of PRA by 1° decrease PFP likelihood by 1.7 times. Conclusion. These results revealed FRA, SAB and PRA to have best predictive value for patellofemoral pain. Current findings can help to assess the complexity of predisposing factors for PFP in practice
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