Discrete Dynamical Systems: A Brief Survey

Dynamical system is a mathematical formalization for any fixed rule that is described in time dependent fashion. The time can be measured by either of the number systems - integers, real numbers, complex numbers. A discrete dynamical system is a dynamical system whose state evolves over a state space in discrete time steps according to a fixed rule. This brief survey paper is concerned with the part of the work done by José Sousa Ramos [2] and some of his research students. We present the general theory of discrete dynamical systems and present results from applications to geometry, graph theory and synchronization

Self Esteem between Assam Police Trainees and Sports persons - A Comparative Study

The aim of the study was to compare self esteem between Assam Police trainees and sports persons. The researchers selected total 50 (fifty) subject’s i.e. N1=25 Assam Police (AP) trainees from 2nd AP Battalion Camp, Makum, Tinsukia, Assam, India and N2=25 sports person from Dibrugarh University Post Graduate team participated different Inter-college level Tournament and between the 19-22 years age. The purposive sampling technique was used to select the subjects. To collect the data, the Rosenberg Self-Esteem Scale was used. To determine the differences between the groups the Independent t-test was applied and the level of significance was kept at 0.05confidence. The result showed that statistically there was significant difference between the groups (t0.05 (48) = 3.55 > 1.677)

Development of a collagen-based scaffold for sequential delivery of antimicrobial agents and pdgf genes to chronic wounds

Chronic wounds are a global health burden affecting more than 5 million people in the United States alone. The complex wound microenvironment causes variable therapeutic outcomes following treatment with commercially available products. Wound infection is one of the major barriers in healing of wounds and localized delivery of antimicrobials is necessary for treatment. Furthermore, growth factors play a vital role in orchestrating the wound healing process through enhancement of cell proliferation, migration, and extracellular matrix remodeling. Accordingly, we have developed a collagen-based scaffold modified with combination of vancomycin-loaded liposomes and platelet derived growth factor (PDGF)-loaded DNA polyplexes. Both the liposomes and polyplexes were anchored to collagen using collagen mimetic peptides (CMPs). Our aim was to use CMP tethering to control the sequential release of vancomycin and PDGF polyplexes to immediately suppress infection and subsequently transfect wound bed fibroblasts with PDGF to assist the wound healing process. Vancomycin-loaded liposomes were prepared using dipalmitoylphosphatidylcholine (DPPC), cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG). The liposomes were 160.7±2.1 nm in diameter based on dynamic light scattering (DLS) analyses, and the loading capacity of vancomycin was 51.5±0.7% in the liposomes. PDGF polyplexes (115.2±1.2 nm in diameter) were prepared by self-assembly of polyethyleneimine and PDGF plasmid DNA (N/P = 8) in 20 mM HEPES buffer (pH = 6.0), and successful PDGF gene loading was confirmed by agarose gel electrophoresis. Co-gels were prepared with collagen (4 mg/mL), fibrinogen (1.25 mg/mL), and thrombin (0.156 IU/mL) combinations that could successfully encapsulate both the vancomycin-loaded liposomes and PDGF polyplexes. Drug release studies confirmed that ~80% of the vancomycin was released during the 48 h study period, whereas PDGF polyplexes were retained longer (\u3e 5 days) in the gel because their release requires collagen degradation mediated by matrix metalloproteinases present in the wound bed. The ability of the PDGF polyplexes to transfect fibroblasts was confirmed by in vitro cell transfection studies using green fluorescent protein (GFP) as a model gene. Furthermore, polyplex-mediated PDGF transfection was evaluated in fibroblasts cultured in an in vitro culture wound model, which showed that PDGF transfection enhanced migration rates of fibroblasts by ~2.4 fold as compared to controls in which culture wounds were allowed to heal in the absence of polyplexes. These results showcase the capacity for sequential delivery of vancomycin and PDGF gene in vitro, using collagen-based scaffolds, for potential applications in in vivo chronic wound treatments

Temperature-dependent proximity magnetism in Pt

We experimentally demonstrate the existence of magnetic coupling between two ferromagnets separated by a thin Pt layer. The coupling remains ferromagnetic regardless of the Pt thickness, and exhibits a significant dependence on temperature. Therefore, it cannot be explained by the established mechanisms of magnetic coupling across nonmagnetic spacers. We show that the experimental results are consistent with the presence of magnetism induced in Pt in proximity to ferromagnets, in direct analogy to the well-known proximity effects in superconductivity.Comment: 4 pages, 3 figure

Tissue Determinants of Human NK Cell Development, Function, and Residence.

Immune responses in diverse tissue sites are critical for protective immunity and homeostasis. Here, we investigate how tissue localization regulates the development and function of human natural killer (NK) cells, innate lymphocytes important for anti-viral and tumor immunity. Integrating high-dimensional analysis of NK cells from blood, lymphoid organs, and mucosal tissue sites from 60 individuals, we identify tissue-specific patterns of NK cell subset distribution, maturation, and function maintained across age and between individuals. Mature and terminally differentiated NK cells with enhanced effector function predominate in blood, bone marrow, spleen, and lungs and exhibit shared transcriptional programs across sites. By contrast, precursor and immature NK cells with reduced effector capacity populate lymph nodes and intestines and exhibit tissue-resident signatures and site-specific adaptations. Together, our results reveal anatomic control of NK cell development and maintenance as tissue-resident populations, whereas mature, terminally differentiated subsets mediate immunosurveillance through diverse peripheral sites. VIDEO ABSTRACT

Retinal nerve fiber layer thickness in glaucomatous Nepalese eyes and its relation with visual field sensitivity.

BACKGROUND: To evaluate peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous Nepalese eyes using spectral domain optical coherence tomography (SD-OCT) and study its relationship with visual field sensitivity. METHODS: A total of 120 eyes comprising primary open angle glaucoma (POAG), glaucoma suspects (GS), normal tension glaucoma (NTG) and healthy subjects (n=30 cases in each group) underwent a complete ophthalmic examination, including optic nerve head (ONH) evaluation and standard automated perimetry (SAP). RNFL thickness measurements around the optic disk were taken with circular spectral domain optical coherence tomography (SD-OCT) scans. Analysis of variance (ANOVA) was used for comparison of RNFL parameters among various study groups. The relationship of RNFL parameters with visual field (VF) global indices was evaluated with regression analysis. RESULTS: The mean pRNFL thickness was significantly less in the POAG (64.30±14.45μm, p<0.01), NTG (85.43±9.79μm, p<0.001) and GS (102.0±9.37μm, p<0.001) groups than in the healthy group (109.8±8.32μm). The RNFL was significantly thinner across all quadrants in all study group pairs (p<0.05) except for normal vs. GS (only superior and inferior quadrant, significant). Linear regression plots with RNFL thickness as a predictor of MD and LV demonstrated a strong and statistically significant degree of determination in the POAG group (R(2)=0.203 and 0.175, p=0.013 and 0.021). CONCLUSION: The RNFL thickness measurements with SD-OCT are lower in glaucomatous eyes as compared to age-matched GS and normal eyes in the Nepalese population. A high resolution SD-OCT could aid significantly in the early diagnosis of glaucoma in Nepal

Achieving highly-enhanced UV photoluminescence and its origin in ZnO nanocrystalline films

AbstractZnO is an efficient luminescent material in the UV-range ∼3.4 eV with a wide range of applications in optical technologies. Sputtering is a cost-effective and relatively straightforward growth technique for ZnO films; however, most as-grown films are observed to contain intrinsic defects which can significantly diminish the desirable UV-emission. In this research the defect dynamics and optical properties of ZnO sputtered films were studied via post-growth annealing in Ar or O2 ambient, with X-ray diffraction (XRD), imaging, transmission and Urbach analysis, Raman scattering, and photoluminescence (PL). The imaging, XRD, Raman and Urbach analyses indicate significant improvement in crystal morphology and band-edge characteristics upon annealing, which is nearly independent of the annealing environment. The native defects specific to the as-grown films, which were analyzed via PL, are assigned to Zni related centers that luminesce at 2.8 eV. Their presence is attributed to the nature of the sputtering growth technique, which supports Zn-rich growth conditions. After annealing, in either environment the 2.8 eV center diminished accompanied by morphology improvement, and the desirable UV-PL significantly increased. The O2 ambient was found to introduce nominal Oi centers while the Ar ambient was found to be the ideal environment for the enhancement of the UV-light emission: an enhancement of ∼40 times was achieved. The increase in the UV-PL is attributed to the reduction of Zni-related defects, the presence of which in ZnO provides a competing route to the UV emission. Also, the effect of the annealing was to decrease the compressive stress in the films. Finally, the dominant UV-PL at the cold temperature regime is attributed to luminescent centers not associated with the usual excitons of ZnO, but rather to structural defects

Effects from Early Planting of Late-Maturing Sunflowers on Damage from Primary Insect Pests in the United States

Delayed planting is recommended to reduce damage from sunflower insect pests in the United States, including the sunflower moth, Homoeosoma electellum (Hulst) and banded sunflower moth, Cochylis hospes Walsingham. However, in some locations, planting earlier or growing later-maturing hybrids could improve yield or oil content of sunflowers which would partially offset any added costs from insect pests or their management. Because the abundance and distribution of some sunflower insects have changed since recommendations for delayed planting were developed, experimental plots were grown in 2012 and 2013 at sites in North Dakota, Nebraska, Iowa, and Illinois. Sunflowers were planted two to four weeks earlier than normal, including hybrids that flower two to three weeks later than elite commercial hybrids. The sum of seed damaged by sunflower moth, banded sunflower moth, and red sunflower seed weevil, Smicronyx fulvus LeConte, (i. e., total percentage) was influenced by location, but not the relative maturity of tested entries. However, when damage attributed solely to the red sunflower seed weevil was analyzed, more damaged seed were found for late-maturing entries in North Dakota and Nebraska. In addition to the trial data, current pest populations are lower than when delayed planting was first recommended and insecticide use during sunflower bloomis both common and effective. Together, these observations suggest factoring insect pests into planting time decisions may be unnecessary, except for areas with a history of problems with severe pests that cannot be managed using insecticides (e. g., sunflower midge, Contarinia schulzi Gagné)

Effects from Early Planting of Late-Maturing Sunflowers on Damage from Primary Insect Pests in the United States

Delayed planting is recommended to reduce damage from sunflower insect pests in the United States, including the sunflower moth, Homoeosoma electellum (Hulst) and banded sunflower moth, Cochylis hospes Walsingham. However, in some locations, planting earlier or growing later-maturing hybrids could improve yield or oil content of sunflowers which would partially offset any added costs from insect pests or their management. Because the abundance and distribution of some sunflower insects have changed since recommendations for delayed planting were developed, experimental plots were grown in 2012 and 2013 at sites in North Dakota, Nebraska, Iowa, and Illinois. Sunflowers were planted two to four weeks earlier than normal, including hybrids that flower two to three weeks later than elite commercial hybrids. The sum of seed damaged by sunflower moth, banded sunflower moth, and red sunflower seed weevil, Smicronyx fulvus LeConte, (i. e., total percentage) was influenced by location, but not the relative maturity of tested entries. However, when damage attributed solely to the red sunflower seed weevil was analyzed, more damaged seed were found for late-maturing entries in North Dakota and Nebraska. In addition to the trial data, current pest populations are lower than when delayed planting was first recommended and insecticide use during sunflower bloomis both common and effective. Together, these observations suggest factoring insect pests into planting time decisions may be unnecessary, except for areas with a history of problems with severe pests that cannot be managed using insecticides (e. g., sunflower midge, Contarinia schulzi Gagné)