Interior Zone Research Articles

Tantalum Oxide Nanoparticles for the Imaging of Articular Cartilage Using X-Ray Computed Tomography: Visualization of Ex Vivo/In Vivo Murine Tibia and Ex Vivo Human Index Finger Cartilage

The synthesis and characterization of tantalum oxide (Ta2O5) nanoparticles (NPs) as new X-ray contrast media for microcomputed tomography (μCT) imaging of articular cartilage are reported. NPs, approximately 5–10 nm in size, and possessing distinct surface charges, were synthesized using phosphonate (neutral), ammonium (cationic), and carboxylate (anionic) ligands as end functional groups. Assessment of a cartilage defect in a human cadaver distal metacarpophalangeal (MCP) joint with the ammonium nanoparticles showed good visualization of damage and preferential uptake in areas surrounding the defect. Finally, an optimized nontoxic cationic NP contrast agent was evaluated in an in vivo murine model and the cartilage was imaged. These nanoparticles represent a new type of contrast agent for imaging articular cartilage, and the results demonstrate the importance of surface charge in the design of nanoparticulate agents for targeting the surface or interior zones of articular cartilage.

Tantalum oxide nanoparticles for the imaging of articular cartilage using X-ray computed tomography: visualization of ex vivo/in vivo murine tibia and ex vivo human index finger cartilage.

The synthesis and characterization of tantalum oxide (Ta2O5) nanoparticles (NPs) as new X-ray contrast media for microcomputed tomography (μCT) imaging of articular cartilage are reported. NPs, approximately 5-10 nm in size, and possessing distinct surface charges, were synthesized using phosphonate (neutral), ammonium (cationic), and carboxylate (anionic) ligands as end functional groups. Assessment of a cartilage defect in a human cadaver distal metacarpophalangeal (MCP) joint with the ammonium nanoparticles showed good visualization of damage and preferential uptake in areas surrounding the defect. Finally, an optimized nontoxic cationic NP contrast agent was evaluated in an in vivo murine model and the cartilage was imaged. These nanoparticles represent a new type of contrast agent for imaging articular cartilage, and the results demonstrate the importance of surface charge in the design of nanoparticulate agents for targeting the surface or interior zones of articular cartilage.

Building Envelope Pressure Manipulation for Streamlined High-Rise Buildings

Methods of manipulating building envelope wind pressure distributions for application in the natural ventilation of high-rise buildings are presented using computer simulation methods. CFD was used to simulate the external flow while the multi-zone method was used to compute the flow distribution in the building interior. First, a 2–D CFD study was conducted to explore various techniques of manipulating the building envelope wind pressure distribution. This study indicated that the use of externally mounted flow-resistance devices is an effective method of manipulating the wind pressure distribution. It was demonstrated that this technique is well suited for application to buildings of streamlined cross-section (e.g. elliptical plan form). Next, a 3–D CFD study was conducted in order to investigate the performance of the flow resistance device concept applied to a full-scale building. The results indicated that it is possible to significantly alter the pressure distributions at different heights of the building by utilizing flow resistance devices. Manipulating the wind pressure distribution was shown to confer the ability to control the direction of the airflow exchange (i.e. intake versus exhaust) in the interior zones of a building.

Mineralogy and trace-element geochemistry of sulfide minerals in hydrothermal chimneys from the Upper-Cretaceous VMS deposits of the eastern Pontide orogenic belt (NE Turkey)

Numerous active hydrothermal chimneys have been discovered on the modern ocean floor, and the structural, textural, and mineralogical features of these chimneys have been described in detail. However, fossil chimneys have not been widely found or studied in detail. Paleo-hydrothermal chimneys were first discovered in Late Cretaceous massive sulfide deposits in the eastern Black Sea district. The well-preserved chimney fragments typically contain distinct concentric sulfide zones. The outer zones of the chimneys contain mainly pyrite and sphalerite and lesser amounts of chalcopyrite. The sulfides within the inner zone consist predominantly of chalcopyrite, with lesser amounts of pyrite and sphalerite. The axial conduits are commonly dominated by barite gangue, with variable amounts of fahlore, sphalerite, chalcopyrite, and galena. The sulfide-rich chimney zones are also characterized by significantly higher metal contents (e.g., Cu, Zn, Fe, Se, Te, Au, Ag). Laser-ablation ICP-MS studies indicate that there is a distinct systematic trace element distribution throughout the horizontal sections of the chimneys. In general, Mn, Co, Ni, Tl, U, and V are enriched in the outermost zones of the chimneys and decrease toward the interior zones. Elements indicative of higher temperature conditions, including Mo, Se, Sn, and Cu, are generally enriched in the inner zones of the chimneys. The highest contents of most of the trace elements are present within the outer walls of the chimneys, suggesting rapid precipitation in high-gradient conditions.These chimney fragments are important evidence of hydrothermal vents in the Cretaceous ocean floor in the eastern Pontides. The presence of mineralized chimney fragments in the massive sulfide deposits of the eastern Pontides and their trace element contents also provides significant data for understanding the physicochemical conditions and depositional histories of massive sulfide mineralizations on the seafloor.

Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone

Thompson, D. J. 2014. Relating germination requirements of timber milkvetch to seral stage in the Interior Douglas-fir zone. Can. J. Plant Sci. 94: 723–726. Germination of timber milkvetch (Astragalus miser var. serotinus) seeds was studied to determine if it is an early or late seral species. Seeds were collected from a native plant population and those having a dark seed coat were selected. Germination tests were run in the light or dark and under three temperature regimes: low (constant 10°C), high (constant 25°C), and alternating (25°C day and 10°C night). Germination occurred over a protracted period with new germinants up to 90 d at the lowest temperature. Germination was not affected by light. Germination rate was greater at 25°C than 10°C, while fluctuating temperatures (25 and 10°C alternating every 12 h) reduced germination rate to that at the lower temperature. Days to 50% germination was a more sensitive indicator, with the mean for the fluctuating temperatures falling between those continuous to the high and low temperature. Final germination percentage was reduced at 10°C compared with 25°C, but not with fluctuating temperatures. Timber milkvetch seed germination did not respond to light or fluctuating temperatures, adding to a body of evidence that it is a late seral species.

Spatial and Temporal Variability of Rainfall over the South-West Coast of Bangladesh

This study examined the spatial and temporal rainfall variability from the 1940s to 2007 in the south west coastal region of Bangladesh. Time series statistical tests were applied to examine the spatial and temporal trends in three time segments (1948–1970, 1971–1990 and 1991–2007) and four seasons (Pre-monsoon; Monsoon; Post-Monsoon and Winter), during the period 1948–2007. Eight weather stations were divided into two zones: exposed (exposed to sea) and interior (distant to sea). Overall, rainfall increased during the period 1948–2007, while the trends intensified during post-1990s. Post-monsoon and winter rainfall was observed to follow significant positive trends at most weather stations during the time period 1948–2007. The rate of change was found in exposed zone and interior zone are +12.51 and +4.86 mm/year, respectively, over post monsoon and +0.9 and +1.86 mm/year, respectively, over winter. These trends intensified both in the exposed zone (+45.81 mm/year) and the interior zone (+27.09 mm/year) 1990 onwards. Winter rainfall does not exhibit significant change (p > 0.1) over the exterior or interior zone, though individual stations like Jessore, Satkhira and Bhola show significant negative trends after 1990s. Although the trends were observed to weaken in the monsoon and pre-monsoon seasons, they are not significant. Moreover, an 11-year cyclicity was found within these two seasons, whilst no cyclicity was observed in the post-monsoon and winter seasons. Sequential Mann Kendal test reveals that the changes in two zones rainfall trends are started around mid-80s, where step change found only for fours season in Khulna stations and also for winter seasons in all weather stations. These changes may have a detrimental effect on rain-fed agriculture in Bangladesh. The application of palaeo-environmental techniques, threshold determination and rainfall analysis across the whole country could be useful to support adaptation planning of the rain-fed agro-economy in Bangladesh.

Petrology of chromite in ureilites: Deconvolution of primary oxidation states and secondary reduction processes

Ureilites are ultramafic achondrites thought to be residues of partial melting on a carbon-rich asteroid. They show a trend of FeO-variation (olivine Fo from ∼74 to 95) that suggests variation in oxidation state. Whether this variation was established during high-temperature igneous processing on the ureilite parent body (UPB), or preserved from nebular precursors, is a subject of debate. The behavior of chromium in ureilites offers a way to assess redox conditions during their formation and address this issue, independent of Fo. We conducted a petrographic and mineral compositional study of occurrences of chromite (Cr-rich spinel) in ureilites, aimed at determining the origin of the chromite in each occurrence and using primary occurrences to constrain models of ureilite petrogenesis. Chromite was studied in LEW 88774 (Fo 74.2), NWA 766 (Fo 76.7), NWA 3109 (Fo 76.3), HaH 064 (Fo 77.5), LAP 03587 (Fo 74.9), CMS 04048 (Fo 76.4), LAP 02382 (Fo 78.6) and EET 96328 (Fo 85.2).Chromite occurs in LEW 88774 (∼5vol.%), NWA 766 (<1vol.%), NWA 3109 (<1vol.%) and HaH 064 (<1vol.%) as subhedral to anhedral grains comparable in size (∼30μm to 1mm) and/or textural setting to the major silicates (olivine and pyroxenes[s]) in each rock, indicating that it is a primary phase. The most FeO-rich chromites in these sample (rare grain cores or chadocrysts in silicates) are the most primitive compositions preserved (fe#=0.55–0.6; Cr# varying from 0.65 to 0.72 among samples). They record olivine–chromite equilibration temperatures of ∼1040–1050°C, reflecting subsolidus Fe/Mg reequilibration during slow cooling from ∼1200 to 1300°C. All other chromite in these samples is reduced. Three types of zones are observed. (1) Inclusion-free interior zones showing reduction of FeO (fe# ∼0.4→0.28); (2) Outer zones showing further reduction of FeO (fe# ∼0.28→0.15) and containing abundant laths of eskolaite–corundum (Cr2O3–Al2O3); (3) Outermost zones showing extreme reduction of both FeO (fe# <0.15) and Cr2O3 (Cr# as low as 0.2). The grains are surrounded by rims of Si-Al-rich glass, graphite, Fe, Cr-carbides ([Fe,Cr]3C and [Fe,Cr]7C3), Cr-rich sulfides (daubréelite and brezinaite) and Cr-rich symplectic bands on adjacent silicates. Chromite is inferred to have been reduced by graphite, forming eskolaite–corundum and carbides as byproducts, during impact excavation. This event involved initial elevation of T (to 1300–1400°C), followed by rapid decompression and drop in T (to <700°C) at 1–20°C/h. The kinetics of reduction of chromite is consistent with this scenario. The reduction was facilitated by silicate melt surrounding the chromites, which was partly generated by shock-melting of pyroxenes. Symplectic bands, consisting of fine-scale intergrowths of Ca-pyroxene, chromite and glass, formed by reaction between the Cr-enriched melt and adjacent silicates.Early chromite also occurs in a melt inclusion in olivine in HaH 064 and in a metallic spherule in olivine in LAP 02382. LAP 03587 and CMS 04048 contain ⩽μm-sized chromite+pyroxene symplectic exsolutions in olivine, indicating high Cr valence in the primary olivine. EET 96328 contains a round grain of chromite that could be a late-crystallizing phase. Tiny chromite grains in melt inclusions in EET 96328 formed in late, closed-system reactions.For 7 of the 8 ureilites we conclude that the relatively oxidizing conditions evidenced by the presence of primary or early chromite pertain to the period of high-T igneous processing. The observation that such conditions are recorded almost exclusively in low-Fo samples supports the interpretation that the ureilite FeO-variation was established during igneous processing on the UPB.

Decision making of HVAC system using Bayesian Markov chain Monte Carlo method

Building simulation has become an indispensable decision making tool since it is capable of capturing dynamic behavior of building systems and predicting impact of energy saving components. However, it has been well acknowledged that simulation prediction is often significantly influenced by treatment of uncertain inputs. This paper presents multi-criteria (construction cost, total energy consumption) decision making of HVAC systems under uncertainty. In this study, a library building was selected and modeled using EnergyPlus 6.0. There were two HVAC candidates: (1) variable air volume (VAV) for interior zone+fan coil unit (FCU) for perimeter zone+gas boiler+electric chiller, (2) VAV+FCU+gas boiler+electric chiller+ice thermal storage system. For uncertainty analysis, unknown inputs were identified based on the literature and the Latin hypercube sampling (LHS) method was employed. Then, Bayesian decision theory was applied to solve stochastic decision making. In particular, the paper includes preferences of building stakeholders (three architects, four simulation experts, three HVAC experts) by using Markov chain Monte Carlo (MCMC). It is shown that such quantitative stochastic appraisal yields more meaningful information than the traditional deterministic approach, and helps to improve confidence in simulation results.

Road traffic accidents in Singapore expressway tunnels

In rapidly growing economies with limited land space, underground road tunnels are becoming more prevalent. Before the implementation of large-scale underground road systems, it is necessary to garner more knowledge on their implications and impacts. This study examined 608 road traffic accidents (RTAs) that occurred in the three Singapore expressway tunnels, over 2009–2011. Each road tunnel was divided into three zones and RTA characteristics were analysed for each zone. The analyses reveal that RTA rates are higher in the transition zones compared to the interior zones, being mostly attributed to multivehicle crashes. However, mean casualty per RTA was found to be higher in the interior zones. Upon disaggregation by travel direction, it was found that RTAs are more likely to occur when entering the tunnel than exiting. The implications of the findings are discussed.

Research on Tunnel Interior Zone Luminance Evaluation Method and its Application

Because of the special traffic environment, the tunnel is called a bottleneck on the highway sections; there is a huge risk of safe operation. Tunnel interior zone lighting plays an important role in the tunnel; good lighting can eliminate depression and driving fatigue of the driver in the tunnel. In this paper, freeway tunnel interior zone lighting is as the research object. We analyzed the driver's demand for freeway tunnel interior zone lighting and transformed illumination to luminance in the model of driver workload, operating speed and the illumination. And this model is established by our group. According to comfortable and relatively comfortable driving workload intense threshold, we can get the safe and comfortable luminance threshold of tunnel interior zone. This paper proposed a detection and evaluation method in freeway tunnel interior zone luminance, and the method have been applied and verified on one freeway in south China.

A multiscale constitutive model for intergranular stress corrosion cracking in type 304 austenitic stainless steel

Intergranular stress corrosion cracking (IGSCC) is a fracture mechanism in sensitised austenitic stainless steels exposed to critical environments where the intergranular cracks extends along the network of connected susceptible grain boundaries. A constitutive model is presented to estimate the maximum intergranular crack growth by taking into consideration the materials mechanical properties and microstructure characters distribution. This constitutive model is constructed based on the assumption that each grain is a two phase material comprising of grain interior and grain boundary zone. The inherent micro-mechanisms active in the grain interior during IGSCC is based on crystal plasticity theory, while the grain boundary zone has been modelled by proposing a phenomenological constitutive model motivated from cohesive zone modelling approach. Overall, response of the representative volume is calculated by volume averaging of individual grain behaviour. Model is assessed by performing rigorous parametric studies, followed by validation and verification of the proposed constitutive model using representative volume element based FE simulations reported in the literature. In the last section, model application is demonstrated using intergranular stress corrosion cracking experiments which shows a good agreement.

Truffle Brûlés Have an Impact on the Diversity of Soil Bacterial Communities

BackgroundThe development of Tuber melanosporum mycorrhizal symbiosis is associated with the production of an area devoid of vegetation (commonly referred to by the French word ‘brûlé’) around the symbiotic plants and where the fruiting bodies of T. melanosporum are usually collected. The extent of the ecological impact of such an area is still being discovered. While the relationship between T. melanosporum and the other fungi present in the brûlé has been assessed, no data are available on the relationship between this fungus and the bacteria inhabiting the brûlé.Methodology/Principal FindingsWe used DGGE and DNA microarrays of 16S rRNA gene fragments to compare the bacterial and archaeal communities inside and outside of truffle brûlés. Soil samples were collected in 2008 from four productive T. melanosporum/Quercus pubescens truffle-grounds located in Cahors, France, showing characteristic truffle brûlé. All the samples were analyzed by DGGE and one truffle-ground was analyzed also using phylogenetic microarrays. DGGE profiles showed differences in the bacterial community composition, and the microarrays revealed a few differences in relative richness between the brûlé interior and exterior zones, as well as differences in the relative abundance of several taxa.Conclusions/SignificanceThe different signal intensities we have measured for members of bacteria and archaea inside versus outside the brûlé are the first demonstration, to our knowledge, that not only fungal communities, but also other microorganisms are affected by T. melanosporum. Firmicutes (e.g., Bacillus), several genera of Actinobacteria, and a few Cyanobacteria had greater representation inside the brûlé compared with outside, whereas Pseudomonas and several genera within the class Flavobacteriaceae had higher relative abundances outside the brûlé. The findings from this study may contribute to future searches for microbial bio-indicators of brûlés.

Modelling of groundwater–vegetation interactions in a tidal marsh

Wetting and drying due to tidal fluctuations affect soil conditions and hence plant growth in tidal marshes. Here, a coupled one-dimensional model was developed to simulate interacting groundwater flow and plant growth in these wetlands. The simulation results revealed three characteristic zones of soil conditions for plant growth along a cross-creek section subjected to the combined influences of spring-neap tides and evapotranspiration: (1) a near-creek zone affected by semi-diurnal tides over the whole spring-neap cycle, where the soil is well aerated although the plant growth could be slightly limited by the local water content dropping periodically below the wilting point on the ebb tide; (2) a less well-drained zone where drainage occurs only during neap tides (for which the daily inundation is absent) and plant growth is aeration-limited; and (3) an interior zone where evapotranspiration determines the soil–water saturation. Plant growth dynamics, which depend on these soil conditions, lead to spatial biomass distributions that are consistent with the characteristic zonation. The simulations shed light on the feedback mechanism for groundwater–vegetation interactions in the marsh system. It was demonstrated that the growth of pioneer plants can improve the soil aeration condition as a result of transpiration. The strength of this feedback varies spatially in accordance with the three characteristic zones of soil–water saturation. However, the development of another species in the marsh system is likely to be more complicated than suggested by the “positive feedback” mechanism proposed previously, due to the influence of inter-species competition. The feedback effects are generally more complex, involving both plant growth enhancement and inhibition depending on the combined influence of the intra- and inter-species competition, the ecosystem’s carrying capacity and plant transpiration. These findings demonstrate the interplay of ecological and hydrological processes in tidal marshes, and provide guidance for future research, including field investigations that aim to establish the principle relationship between marsh morphology and plant zonation.

Modeling of thermophysical properties in heterogeneous periodic media according to a multi-scale approach: Effective conductivity tensor and edge effects

The homogenization theory is a powerful approach to determine the effective thermal conductivity tensor of heterogeneous materials such as composites, including thermoset matrix and fibers. Once the effective properties are calculated, they can be used to solve a heat conduction problem on the composite structure at the macroscopic scale. This approach leads to good approximations of both the heat flux and temperature fields in the interior zone of the structure; however edge effects occur in the vicinity of the domain boundaries. In this paper, following an approach proposed for elasticity problems, it is shown how these edge effects can be accounted for. An additional asymptotic expansion term is introduced, which plays the role of a “heat conduction boundary layer” (HCBL) term. This expansion decreases exponentially and tends to zero far from the boundary. Moreover, the HCBL length can be determined from the solution of an eigenvalues problem. Numerical examples are considered for a standard multilayered material and for a unidirectional carbon-epoxy composite. The homogenized solutions computed with a finite element software, and corrected with the HCBL terms are compared to a heterogeneous finite element solution at the microscopic scale. The influences of the thermal contrast and the scale factor are illustrated for different kind of boundary conditions.

Pilot study on the significance of random intrasite placement of the Semmes–Weinstein monofilament

The possible effect of random intrasite placement on the outcome of the Semmes-Weinstein monofilament (SWF) test is not known. We sought to determine the significance of this variable in the diagnosis of loss of protective sensation (LOPS) in patients with diabetes. Forty-five patients with diabetes with history of pedal ulceration (group 1), 81 patients with diabetes without history of ulceration (group 2) and 21 non-diabetic controls (group 3) were studied. The three original sites of the International Consensus on the Diabetic Foot at the hallux, first and fifth sub-metatarsal areas were divided into peripheral and interior zones resulting in a total of six zones. Mean total scores of monofilament test were significantly lower in peripheral zones as compared with interior zones of both feet in all three groups and affected the resulting percentage of loss of protective sensation. Intrasite monofilament placement can significantly affect monofilament test results and the diagnosis of loss of protective sensation. A model that corrects the effect of random intrasite placement is needed.

Shortening, structural relief and drainage evolution in inverted rifts: insights from the Atlas Mountains, the Eastern Cordillera of Colombia and the Pyrenees

Abstract The Atlas, Eastern Cordillera and Pyrenees are thick-skinned thrust-fold belts formed by tectonic inversion of rift basins in continental settings. A comparison of shortening between them shows a gradation from 20–25% in the central High Atlas, to 25–30% in the Eastern Cordillera, and c. 40% in the Pyrenees. Accordingly, there is a structural variation from interior zones with low structural relief and isolated basement massifs in the first two cases, to an axial culmination of stacked basement thrust sheets in the Pyrenees. This results in marked topographic and drainage variation: the High Atlas and Eastern Cordillera contain axial plateaus dominated by structure-controlled longitudinal rivers and orogen flanks with slope-controlled transverse rivers, whereas the Pyrenees show a two-sided wedge profile dominated by transverse rivers. In spite of singularities exhibited by each orogen, we propose that this spatial variation can be understood as reflecting different degrees of evolution in mountain building. Rapidly incising, transverse rivers are capturing earlier longitudinal streams of the Atlas and Eastern Cordillera, thus reducing their axial plateaux, which will eventually disappear into a transverse-dominated drainage. This pattern of landscape evolution may be characteristic of inversion orogens as they develop from initial stages of inversion to full accretion.

Thermal properties of composite materials : effective conductivity tensor and edge effects

The homogenization theory is a powerful approach to determine the effective thermal conductivity tensor of heterogeneous materials such as composites, including thermoset matrix and fibres. Once the effective properties are calculated, they can be used to solve a heat conduction problem on the composite structure at the macroscopic scale. This approach leads to good approximations of both the heat flux and temperature in the interior zone of the structure, however edge effects occur in the vicinity of the domain boundaries. In this paper, following the approach proposed in [10] for elasticity, it is shown how these edge effects can be corrected. Thus an additional asymptotic expansion is introduced, which plays the role of a edge effect term. This expansion tends to zero far from the boundary, and is assumed to decrease exponentially. Moreover, the length of the edge effect region can be determined from the solution of an eigenvalue problem. Numerical examples are considered for a standard multilayered material. The homogenized solutions computed with a finite element software, and corrected with the edge effect terms, are compared to a heterogeneous finite element solution at the microscopic scale. The influences of the thermal contrast and scale factor are illustrated for different kind of boundary conditions.

Auditing and analysis of energy consumption of an educational building in hot and humid area

Electric energy consumption is becoming an important issue for individual as well as for governmental and private organizations. Electric companies in Saudi Arabia face hard times in meeting the increasing demand for electric power. This research investigation is trying to study the electric energy consumption for an educational building located in Rabigh city, 150km North of Jeddah city, Saudi Arabia. Detailed auditing was done to the building including constructing materials used, energy consumption, cooling load and lighting. Temperature and relative humidity were recorded for several places inside the building. Thermal images for the interior zones were generated to provide information about the temperature distribution and give an idea about air or heat leak from or into the building. Based on the analysis of auditing exercise, some recommendations were suggested to reduce the electric energy consumptions which can reach up to 35.3%. The A/C units’ efficiency can also be increased by 31%. The results will be beneficial for the educational organizations and operation and maintenance staff to manage the electric usage and reduce the electric bills.

Effect of Reflective Fabric on Yield of Mature ‘d’Anjou’ Pear Trees

Reflective fabric was installed before bloom in 2009 and 2010 in alleyways of a mature, low-density ‘Anjou’ pear orchard (269 trees/ha). Four treatments were applied to study intracanopy light environments on fruit growth rate and size, cropload, yield, and fruit quality: 1) no fabric (NF); 2) partial-season fabric applied before full bloom (FB) and removed 75 days after full bloom (dafb) (PSF); 3) full-season fabric applied before FB and removed at harvest (FSF); and 4) shadecloth (60%) applied 60 dafb through harvest (SC). PSF and FSF improved yield by 12% and 18%, respectively, over the two-year period relative to NF. The high yields of fabric treatments were attributed to fruit number in the lower (less than 2.4 m) interior, mid-, and exterior zones of the canopy. Photosynthetic active radiation (PAR) was increased by fabric 28%, 95%, and 30% in the lower exterior, mid-, and interior canopy, respectively. Photosynthesis:light response curves indicated improved carbon assimilation of pear leaves developing in the elevated PAR environment of the lower canopy. Fruit growth rate and final size were unaffected by fabric treatments. FSF fruit size was similar to NF despite higher fruit density. Compared with NF, FSF had a small, non-significant effect on fruit maturity (increased softening) at harvest. Yield and fruit size of SC fruit were significantly reduced. The number of fruit in SC trees did not differ from NF in 2009, but the effect of shade reduced fruit number in 2010. Fabric did not affect fruit quality attributes after three and six months of regular atmosphere cold storage. Pears from SC trees did not attain ripening capacity after three months of cold storage and a 7-day ripening period and had lower sugar content compared with other treatments. The cumulative yield advantages associated with FSF support its use in mature pear orchards.

Water Quality Gradients in the Northern Florida Everglades

The Loxahatchee National Wildlife Refuge (Refuge) developed as a system with waters low in nutrients. Today, the Refuge wetlands are impacted by inflows containing elevated nutrient concentrations originating from agricultural sources. We analyzed water quality sampled at 54 sites in the Refuge. The Refuge was divided into northern, central, and southern latitudinal areas and then perimeter, transition, and the interior zones based on distance from the canal towards the Refuge interior. In the perimeter zone, total dissolved solids (TDS), silicon (Si), and total phosphorus (TP) concentrations in water were higher in the northern than the central area and TDS, Si, SO4, and TP concentrations in water were higher in the central than the southern area. In general TDS, Ca, Cl, Si, SO4, and TP loads in the northern perimeter, transition, and interior zones decreased from 2005 to 2009. The decrease is less pronounced in the central and southern areas than the northern area. As water flowed southward for over 30 km from the northern to the southern area in the perimeter zone, most water quality parameters analyzed were reduced in the water column. However, large amounts of Ca and Cl were added to the water column indicating that canal water is continually diffusing and intruding into the Refuge in all zones. In the perimeter zone, and to a lesser degree in the transition zone, the Refuge has accumulated substantial amounts of Ca, Si, SO4, and TP in vegetation and soils during the sampling period.