The transition from feudalism to capitalism; a symposium

https://stars.library.ucf.edu/prism/1614/thumbnail.jp

Electrical conductivity and luminescence in Cadmium Sulphide

The work is conveniently divided into two sections:- (i) the electrical properties of cadmium sulphide and (ii) the optical properties of cadmium sulphide.(i) Measurements have been made on thin pure platelets of cadmium sulphide from which it is clear that electrical conduction in these samples is governed by two complex defect centres with associated levels within the forbidden gap (0.41 eV - 0.61 eV; 0.25 eV - 0.83). This has been deduced from measurements of the static current- voltage curves made over a wide range of temperatures coupled with an investigation of thermally stimulated current curves obtained after electron injection and optical excitation. The measurements also demonstrate that Lamport theory of Space Charge Limited Current Flow in an insulator with traps is applicable at low current densities but that trap emptying occurs when high current densities are passed through a crystal.(ii) Measurements of the spectral distribution of ultra-violet stimulated fluorescence at 77 K and 300 K, demonstrate the existence of electronic energy levels within the forbidden gap which can be correlated with those determined from the electrical experiments. The spectral distribution of luminescent emission has been measured in pure and doped samples from which it is concluded that edge emission is associated with both sulphur vacancies and interstitials (0.13 eV below the conduction band and 0.16 eV above the valence band respectively.). The two emission series can be separate in suitable crystals. Further work, with better resolution of the emission bands should clarify the position further. Electro-luminescence, due to the recombination of injected electrons and holes, is attributes to bulk processes which produce the edge emission series, surface and impurity recombination

Determining the role of environmental factors and disturbance in the distribution of reed canary grass within wetlands

Reed canary grass (Phalaris arundinacea L.) is an invasive species originally from Europe that has now expanded to a large range within the United States. Reed canary grass possesses a number of traits that allow it to thrive in a wide range of environmental factors, including high rates of sedimentation, bouts of flooding, and high levels of nutrient inputs. Therefore, the goals of our study were to determine if 1) certain types of wetland were more susceptible to Reed canary grass invasion, and 2) disturbances facilitated Reed canary grass invasion. This study was conducted within the Keweenaw Bay Indian Community reservation in the Upper Peninsula of Michigan, in Baraga County. We selected 28 wetlands for analysis. At each wetland, we identified and sampled distinct vegetative communities and their corresponding environmental attributes, which included water table depth, pH, conductivity, calcium and magnesium concentrations, and percent organic matter. Disturbances at each site were catalogued and their severity estimated with the aid of aerial photos. A GIS dataset containing information about the location of Reed canary grass within the study wetlands, the surrounding roads and the level of roadside Reed canary grass invasion was also developed. In all, 287 plant species were identified and classified into 16 communities, which were then further grouped into three broad groupings of wetlands: nonforested graminoid, Sphagnum peatlands, and forested wetlands. The two most common disturbances identified were roads and off-road recreation trails, both occurring at 23 of the 28 sites. Logging activity surrounding the wetlands was the next most common disturbance and was found at 18 of the sites. Occurrence of Reed canary grass was most common in the non-forested graminoid communities. Reed canary grass was very infrequent in forested wetlands, and almost never occurred in the Sphagnum peatlands. Disturbance intensity was the most significant environmental factor in explaining Reed canary grass occurrence within wetlands. Statistically significant relationships were identified at distances of 1000 m, 500 m, and 250 m from studied wetlands, between the level of road development and the severity of Reed canary grass invasion along roadsides. Further analysis revealed a significant relationship between roadside Reed canary grass populations and the level of road development (e.g. paved, graded, and ungraded)

Space charge limited currents in Cadmium Sulphide

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Marxian socialism.: Power elite or ruling class?

https://stars.library.ucf.edu/prism/1580/thumbnail.jp

New Territories: Reimagined Interiorities

At a time where boundaries within society, culture and technology are continually challenged and redefined; even the commonly understood binary oppositions within areas such as gender, age and digitality (Negroponte, 1995) are becoming less visible, measurable and socially accepted. In this new realm where even physical reality is encroached upon by the digital, are the tangible and perceived distinctions between interior and architecture also becoming extinct? An emergence of more flexible and transitional space appears to not only blur the boundaries of inside and outside, interior and architecture, but also the previous distinctions of function. Space is no longer solely intimated by visual cue, materiality or the physicality of walls and interior objects. Instead we see increased “function neutrality” within buildings, with rising opportunity for user interpretation and “take-over”. This renewed focus on the user can be seen to enrich our built environment, as we embrace a new equality of the interior and relish its new freedom and voice

OXYGEN CONSUMPTION: EFFECT OF LATERAL PEDAL WIDTH VARIATIONS RELATIVE TO Q-ANGLE IN AVID CYCLISTS

Twenty cyclists completed four trials at 50% of maximal effort. Trials were performed at four different lateral widths (0, 20mm, 25mm, and 30mm) by adding a Kneesaver™ pedal spacer between the crank arm and pedal. Each trial lasted five minutes, during which analysis of expired air took place, as well as video analysis for digitizing purposes. The aim of the study was to determine if changing this lateral pedal width affected oxygen consumption and if lateral pedal width changed Q-angle in the cyclists. Statistically width did not affect Q-angle or oxygen consumption, however a significant, but small correlation was found between Q-angle and oxygen consumption

The role of vascular cell adhesion molecule 1/ very late activation antigen 4 in endothelial progenitor cell recruitment to rheumatoid arthritis synovium

Objective Marrow-derived endothelial progenitor cells (EPCs) are important in the neovascularization that occurs in diverse conditions such as cardiovascular disorders, inflammatory diseases, and neoplasms. In rheumatoid arthritis (RA), synovial neovascularization propels disease by nourishing the inflamed and hyperproliferative synovium. This study was undertaken to investigate the hypothesis that EPCs selectively home to inflamed joint tissue and may perpetuate synovial neovascularization. Methods In a collagen-induced arthritis (CIA) model, neovascularization and EPC accumulation in mouse ankle synovium was measured. In an antibody-induced arthritis model, EPC recruitment to inflamed synovium was evaluated. In a chimeric SCID mouse/human synovial tissue (ST) model, mice were engrafted subcutaneously with human ST, and EPC homing to grafts was assessed 2 days later. EPC adhesion to RA fibroblasts and RA ST was evaluated in vitro. Results In mice with CIA, cells bearing EPC markers were significantly increased in peripheral blood and accumulated in inflamed synovial pannus. EPCs were 4-fold more numerous in inflamed synovium from mice with anti–type II collagen antibody–induced arthritis versus controls. In SCID mice, EPC homing to RA ST was 3-fold greater than to normal synovium. Antibody neutralization of vascular cell adhesion molecule 1 (VCAM-1) and its ligand component Α4 integrin potently inhibited EPC adhesion to RA fibroblasts and RA ST cryosections. Conclusion These data demonstrate the selective recruitment of EPCs to inflamed joint tissue. The VCAM-1/very late activation antigen 4 adhesive system critically mediates EPC adhesion to cultured RA fibroblasts and to RA ST cryosections. These findings provide evidence of a possible role of EPCs in the synovial neovascularization that is critical to RA pathogenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56042/1/22706_ftp.pd