Studij četiri- i više-dimenzijskih kozmoloških modela u Lyrovoj geometriji

Exact cosmological solutions for spherically symmetric models, both in four and higher dimensions are obtained within the framework of Lyra geometry. It is observed that there is no singularity at finite past in our four-dimensional model. For the five-dimensional model, the diminision of extra dimension with the evolution of the Universe is exhibited. The physical behaviour of the models is examined in vacuum (for the four-dimensional case) and in the presence of perfect fluids (for both four- and five-dimensional models).U okviru Lyrove geometrije izvodimo točna kozmološka rješenja za sferno-simetrične modele u četiri i više dimenzija. U našem 4-dimenzijskom modelu ne nalazi se singularnost u konačnoj prošlosti. U 5-dimenzijskom se modelu pokazuje nestanak dodatne dimenzije razvojem Svemira. Fizička se svojstva modela ispituju u vakuumu (4-dimenzijski model) i u prisustvu perfektne tekućine (za 4- i 5-dimenzijske modele)

Highly conserved type 1 pili promote enterotoxigenic E. coli pathogen-host interactions

Enterotoxigenic Escherichia coli (ETEC), defined by their elaboration of heat-labile (LT) and/or heat-stable (ST) enterotoxins, are a common cause of diarrheal illness in developing countries. Efficient delivery of these toxins requires ETEC to engage target host enterocytes. This engagement is accomplished using a variety of pathovar-specific and conserved E. coli adhesin molecules as well as plasmid encoded colonization factors. Some of these adhesins undergo significant transcriptional modulation as ETEC encounter intestinal epithelia, perhaps suggesting that they cooperatively facilitate interaction with the host. Among genes significantly upregulated on cell contact are those encoding type 1 pili. We therefore investigated the role played by these pili in facilitating ETEC adhesion, and toxin delivery to model intestinal epithelia. We demonstrate that type 1 pili, encoded in the E. coli core genome, play an essential role in ETEC virulence, acting in concert with plasmid-encoded pathovar specific colonization factor (CF) fimbriae to promote optimal bacterial adhesion to cultured intestinal epithelium (CIE) and to epithelial monolayers differentiated from human small intestinal stem cells. Type 1 pili are tipped with the FimH adhesin which recognizes mannose with stereochemical specificity. Thus, enhanced production of highly mannosylated proteins on intestinal epithelia promoted FimH-mediated ETEC adhesion, while conversely, interruption of FimH lectin-epithelial interactions with soluble mannose, anti-FimH antibodies or mutagenesis of fimH effectively blocked ETEC adhesion. Moreover, fimH mutants were significantly impaired in delivery of both heat-stable and heat-labile toxins to the target epithelial cells in vitro, and these mutants were substantially less virulent in rabbit ileal loop assays, a classical model of ETEC pathogenesis. Collectively, our data suggest that these highly conserved pili play an essential role in virulence of these diverse pathogens

SmartHeLP: Smartphone-based Hemoglobin Level Prediction Using an Artificial Neural Network

Blood hemoglobin level (Hgb) measurement has a vital role in the diagnosis, evaluation, and management of numerous diseases. We describe the use of smartphone video imaging and an artificial neural network (ANN) system to estimate Hgb levels non-invasively. We recorded 10 second-300 frame fingertip videos using a smartphone in 75 adults. Red, green, and blue pixel intensities were estimated for each of 100 area blocks in each frame and the patterns across the 300 frames were described. ANN was then used to develop a model using the extracted video features to predict hemoglobin levels. In our study sample, with patients 20-56 years of age, and gold standard hemoglobin levels of 7.6 to 13.5 g/dL., we observed a 0.93 rank order of correlation between model and gold standard hemoglobin levels. Moreover, we identified specific regions of interest in the video images which reduced the required feature space

Simulation-based analysis of dynamic voltage restorer with sliding mode controller at optimal voltage for power quality enhancement in distribution system

Introduction. Nowadays, power quality issues are of considerable interest to both utilities and end users as they cause significant financial losses to the industrial customers. Due to this, power quality assurance in power distribution systems is very important, when considering commercial and industrial applications. Problem Statement. Unfortunately, sudden faults such as sag, transients, harmonics distortion and notching in the power system create disturbances and affect the load voltages. Out of these, voltage sag and harmonics seriously affect sensitive devices. Harmonics in the power system cause increased heating of equipment and conductors, misfires in variable speed drives, and torque pulsations in motors. Harmonics reduction is considered desirable. Methodology. This paper presents an efficient and robust solution to this problem by using dynamic voltage restorer in series with distribution system. Dynamic voltage restorer is economical and effective solution for protecting sensitive loads from harmonics and sag. Control strategy is adopted with dynamic voltage restorer topology and the performance with the proposed controller is analyzed. Novelty. In this research work modelling, analysis and simulation of dynamic voltage restorer with proportional integral controller and dynamic voltage restorer with sliding-mode controller at optimal voltage is used to improve the dynamic voltage restorer performance by reducing total harmonic distortion. Results. The simulation is performed in MATLAB / Simulink software package and comparative analysis of dynamic voltage restorer with different controllers for distribution system is presented. The proposed scheme successfully reduced percentage total harmonics distortion and voltage sag using dynamic voltage restorer with sliding mode controller at optimal voltage which is found to be 0.38 %.Вступ. Сьогодні питання якості електроенергії викликають значний інтерес як для комунальних підприємств, так і для кінцевих споживачів, оскільки вони завдають значних фінансових втрат промисловим споживачам. У зв’язку з цим забезпечення якості електроенергії в розподільних системах є дуже важливим при розгляді комерційних та промислових застосувань. Постановка задачі. На жаль, раптові несправності, такі як прогини, перехідні процеси, спотворення гармонік і виїмки в енергосистемі створюють збурення та впливають на напругу навантаження. З них провали напруги та гармоніки серйозно впливають на чутливі пристрої. Гармоніки в енергосистемі викликають посилений нагрів обладнання та провідників, пропуски запалювання в приводах із змінною частотою обертання, пульсації крутного моменту в двигунах. Зниження гармонік вважається бажаним. Методологія. У цій статті представлено ефективне та надійне рішення цієї проблеми за допомогою динамічного відновника напруги послідовно з розподільною системою. Динамічний відновник напруги – це економне та ефективне рішення для захисту чутливих навантажень від гармоній та провисань. Прийнято стратегію керування з топологією динамічного відновника напруги та проаналізовано ефективність при використанні запропонованого контролера. Новизна. У цій дослідницькій роботі використовується моделювання, аналіз та чисельне дослідження динамічного відновника напруги з пропорційним інтегральним контролером та динамічного відновника напруги з регулятором ковзного режиму при оптимальній напрузі для підвищення ефективності динамічного відновника напруги за рахунок зменшення сумарних гармонійних спотворень. Результати. Моделювання виконано в програмному комплексі MATLAB / Simulink та представлено порівняльний аналіз динамічного відновника напруги з різними контролерами для розподільчої системи. Запропонована схема успішно зменшила відсоток спотворення сумарних гармонік і провалів напруги за допомогою динамічного відновника напруги з регулятором ковзного режиму при оптимальній напрузі, який становить 0,38 %

Scaling Relations of Dwarf Galaxies without Supernova-Driven Winds

Nearby dwarf galaxies exhibit tight correlations between their global stellar and dynamical properties, such as circular velocity, mass-to-light ratio, stellar mass, surface brightness, and metallicity. Such correlations have often been attributed to gas or metal-rich outflows driven by supernova energy feedback to the interstellar medium. We use high-resolution cosmological simulations of high-redshift galaxies with and without energy feedback, as well as analytic modeling, to investigate whether the observed correlations can arise without supernova-driven outflows. We find that the simulated dwarf galaxies exhibit correlations similar to those observed as early as z~10, regardless of whether supernova feedback is included. We also show that the correlations can be well reproduced by our analytic model that accounts for realistic gas inflow but assumes no outflows, and star formation rate obeying the Kennicutt-Schmidt law with a critical density threshold. We argue that correlations in simulated galaxies arise due to the increasingly inefficient conversion of gas into stars in low-mass dwarf galaxies rather than supernova-driven outflows. We also show that the decrease of the observed effective yield in low-mass objects, often used as an indicator of gas and metal outflows, can be reasonably reproduced in our simulations without outflows. We show that this trend can arise if a significant fraction of metals in small galaxies is spread to the outer regions of the halo outside the stellar extent via mixing. In this case the effective yield can be significantly underestimated if only metals within the stellar radius are taken into account. Measurements of gas metallicity in the outskirts of gaseous disks of dwarfs would thus provide a key test of such explanation.Comment: accepted for publication in ApJ, 19 pages, 12 figures, uses emulateapj

Morphological and physiological variation among different isolates of Alternaria spp. from Rapeseed-Mustard

To find out the Morphological variation on growth and sporulation of Alternaria species of Alternaria leaf blight of mustard from 10 representative geographical locations of Bangladesh, this experiment was conducted at Plant Pathology Laboratory, Oilseed Research center, Bangladesh Agricultural Research Inistitute (BARI), Joydevpur, Gazipur, Bangladesh. All the isolates showed high level of variability in in-vitro in respect of radial mycial growth, colony colour, sub surface colour, colony shape, colony texture, zonation (surface and sub surface), length and width of conidia, beak length and number of septa. The maximum and minimum radial mycial growth was recorded 90 mm in isolate NATAb and 83.67 mm in isolate GAZAb, respectively at 14 days after incubation. Significant variation in conidial length, width, beak and no. of conidia observed in all isolates. The length of conidia ranged from 41.56 to 117.54µm with 3 to 11 transverse and 0 to 3 vertical septa. The width and beak length varied from 10.34 to 23.12 µm and 16.78 to 72.65 µm ,respectively. Surface colour were olivacious green to black and circular shaped colonies were observed in all isolates on PDA medium. Colony texture were cottony to velvety. Subsurface colour varied from light brown to black and pinkish. Zonation found in some isolates and some did not produce on both surface and subsurface. All conidia were murifrom and light brown to deep brown in colour. Potato Carrot Dextrose Agar medium (PCDA) and 25 o C temperature were found optimum for different isolates for mycelial growth and sporulation

Surveillance of the Disease Incidence and Severity of Papaya Ringspot Virus at Four Selected Districts of Bangladesh

An experiment was conducted to survey the prevalence of disease incidence and severity of Papaya ringspot virus (PRSV) at eight locations of four districts in Bangladesh. Papaya is one of the most popular fruits in the world. It suffers from several diseases including fungi, bacteria, nematodes and viruses. Among them, viral diseases are found to cause considerable yield loss, with the most important one being PRSV. The survey was conducted at three plain districts and one hill tract area from July 2016 to December 2016. During the survey period, six different symptoms were found in the selected fields and were identified as PRSV based on symptomology. These symptoms were mild mosaic (MM), mosaic (MO), severe mosaic (SM), fern leaf (FL), leaf distortion (LD) and vein clearing (VC). The highest disease incidence (36.24%) was found in BSMRAU farm in Gazipur whereas the lowest (12.04%) was found in Panchari, Khagrachari hill tract. The maximum severity (11.53%) was found in BSMRAU campus, Gazipur on the country and the lowest severity (2.50%) was found in Panchari, Khagrachari hill tract. The yield and yield contributing parameters of papaya found to be differ significantly among the surveyed area. The lowest fruit weight (324.3 gm) due to PRSV infection was recorded in BSMRAU, Gazipur while the highest fruit weight (643.6 gm) was conducted in SAU Campus, Dhaka