Academic literature on the topic 'Arid'

Objective. Hepatocellular carcinoma (HCC) is one of the most lethal malignancies with a poor prognosis. The AT-rich interaction domain (ARID) family plays an essential regulatory role in the pathogenesis and progression of cancers. This study aims to evaluate the prognostic value and clinical significance of human ARID family genes in HCC. Methods. ONCOMINE and The Cancer Genome Atlas (TCGA) databases were employed to retrieve ARIDs expression profile and clinicopathological information of HCC. Kaplan–Meier plotter and MethSurv were applied to the survival analysis of patients with HCC. CBioPortal was used to analyze genetic mutations of ARIDs. Gene Expression Profiling Interactive Analysis (GEPIA) and Metascape were used to perform hub gene identification and functional enrichment. Results. Expression levels of 11 ARIDs were upregulated in HCC, and 2 ARIDs were downregulated. Also, 4 ARIDs and 5 ARIDs were correlated with pathologic stages and histologic grades, respectively. Furthermore, higher expression of ARID1A, ARID1B, ARID2, ARID3A, ARID3B, ARID5B, KDM5A, KDM5B, KDM5C, and JARID2 was remarkably correlated with worse overall survival of patients with HCC, and the high ARID3C/KDM5D expression was related to longer overall survival. Multivariate Cox analysis indicated that ARID3A, KDM5C, and KDM5D were independent risk factors for HCC prognosis. Moreover, ARIDs mutations and 127 CpGs methylation in all ARIDs were observed to be significantly associated with the prognosis of HCC patients. Besides, our data showed that ARIDs could regulate tumor-related pathways and distinct immune cells in the HCC microenvironment. Conclusions. ARIDs present the potential prognostic value for HCC. Our findings suggest that ARID3A, KDM5C, and KDM5D may be the prognostic biomarkers for patients with HCC.

Desertification constitutes a natural hazard for human livelihood, wildlife and vegetation worldwide. Arid and semi-arid areas are the most likely to undergo processes of desertification, and it is a concern of the international community to control, monitor and prevent such a phenomenon. As a mainly arid region, the Middle East is particularly vulnerable to climate-induced impacts on water resources, challenged by high growth population rates and a water-stressed situation. Aim of the reasearch is to investigate Remote Sensing (RS) techniques for desertication studies, with a special focus on the Middle East region. RS is an efficient tool for environmental studies on wide areas of the Earth surface, allowing fast and reproducible analysis on regional and continental scales . For this research two RS methods of change detection analysis have been investigated and further implemented: Change Vector Analysis (CVA), applied to the Tasselled Cap Transform (TCT) outputs, and the Maximum Autocorrelation Factor (MAF) transformation of the Multivariate Alteration Detector (MAD) components (MAD/MAF). The research introduces improvements in the use of both techniques adapting them to desertification studies and proposes a new RS methodology, which has been proven effective in detecting the surface change in arid and semi-arid areas. An added value of the research is the availability of the source code, implemented for this study, to other users, through GFOSS software.

Deserts comprise the largest terrestrial biome, making up approximately one third of the Earth’s land mass. They are defined in terms of moisture deficit using the Aridity Index with values <1. A further delineation based on mean annual temperatures into hot (>18°C), cold (<18°C) and polar (<0°C) deserts is employed. In the absence of significant macrobiota, microorganisms are key to desert ecosystems. They are located in near-surface soils, and include a widespread hypolithic mode of colonization, where microbial biomass develops on the ventral surfaces of quartz and other translucent stones. A literature review was conducted to appreciate the status of existing knowledge on these systems. Amongst unresolved questions that arose were the following, which form the basis of this inquiry: What are the taxonomic and functional differences between hypolithic and near-soil communities? Do hypolithic communities assemble differently in deserts of different xeric and thermal stresses? Can the keystone cyanobacterial taxa be cultivated under laboratory conditions to allow manipulative studies? The Mojave Desert in the USA was used as a model to test the extent to which hypolithic and near-surface soil communities vary in both taxonomic and putative functional composition. A common phylogenetic marker (16S rRNA gene ITS region) was used to conclude that soil and hypolithic communities are significantly different, although both were dominated by cyanobacteria. The ubiquitous hypolithic cyanobacterial taxon Chroococcidiopsis was encountered, although communities appeared to be dominated functionally by the diazotrophic genus Nostoc. The data strongly suggest that carbon and nitrogen fixation pathways in desert soils are mediated by the same taxa, although heterotrophic pathways may differ and support distinct assemblages of heterotrophic bacteria. An opportunistic sampling of three sites along a latitudinal gradient in China allowed some inference about adaptations in hypoliths. Communities recovered from the cold Tibetan Desert, Taklamakan Basin Desert, and exposed hillsides in tropical Hong Kong, did not display significant differences at the level of community assembly. This suggests that hypolithic taxa undergo strong selection for xeric and extreme thermal stresses. A cultivation strategy for the keystone taxon Chroococcidiopsis has been lacking and is an obvious impediment to manipulative physiological studies. Here various methods for laboratory cultivation were attempted. This bacterium proved extremely fastidious and displayed slow growth rates. After extensive trials a novel cultivation method was developed. This involved using plastic petri dishes containing liquid growth medium, into which glass coverslips were introduced along with cell suspensions. The surface energy of glass served as a nucleation site for Chroococcidiopsis biofilms (which do not develop on plastic surfaces) and this method was evaluated in growth studies as a means of quantifying growth. This research includes key advances to demonstrate that hypoliths and soil, whilst supporting different communities, likely perform similar functional roles in the desert soil. Selection due to the severe environmental stresses results in similar communities across large latitudinal and environmental gradients. The development of a cultivation strategy paves the way for manipulative physiological studies on these important organisms.
published_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy

Paper Presented at the Kuwait Symposium on Management and Technology of Water Resources in Arid Zones, Kuwait, October 5-7, 1987.
The use of water harvesting systems in arid lands offers the potential of making lands productive that are now largely unusable due to lack of water for domestic livestock or agricultural use. As long as there is rainfall a water harvesting system can be designed to collect that rainfall and store it until it can be used for beneficial use. The water harvesting system consists of a catchment and a storage facility. If the water is to be used for agriculture it would also include an agricultural area. The agricultural area could be located within the catchment area or in a separate nearby area. Many different treatments have been tested for use in catchment construction. These treatments increase the runoff by decreasing the permeability of the surface and or reducing the time the water stays on the surface or amount of water trapped on the surface. A list of the more promising treatments in order of their increasing cost, are: (1) Shaped compacted-earth; (2) sodium-treated shaped compacted-earth; (3) wax-treated shaped compacted-earth; (4) gravel-covered plastic; (5) fiberglass-asphalt chipcoated; (6) asphalt-plastic-asphalt chipcoated; (7) rubberized-asphalt chipcoated; and (8) reinforced-mortar-covered plastic. The use of compartmented reservoirs make storage of water more efficient. Evaporation and in some cases seepage losses are reduced using the compartmented reservoir by keeping the water concentrated into a volume with as small a surface area as possible. This method of storage when combined with the collection of runoff from a natural surface or with one that is inexpensively treated makes it practical to provide water for supplemental irrigation. This combination is called a water harvesting agrisystem. Concentration of water in a compartmented reservoir can be accomplished in flat terrain using a pump. If the water is being used at a fast enough rate concentration can also be accomplished by selective removal. Alternatively with topography of a sufficient grade, concentration can be accomplished by gravity. Evaporation control on the compartmented reservoir can be improved by placing an evaporation control barrier on the "last" compartment, the one in which water is concentrated and has water in it the longest time. This enhances the value of the evaporation control barrier and increases the dependable water supply. A computer model has been developed to help in the design of the water harvesting systems including agrisystems with compartmented reservoirs. This program fits on portable personal computers and can thus be taken by the designer to a field location to develop an optimum design at a minimum cost. The model can be improved through calibration in a given area as systems are installed and data collected.

This abstract includes the benefits associated with green roofs, how to select the type of green roof for a project, the important technical issues to address during design, implementation and maintenance of its longevity, detailed cost variables for green roof controlling quantity and quality of stormwater, cultivating the crop, and improving aesthetic environments in work and home settings in arid and semi arid regions. Much less rainfall goes into the soil and rest becomes stormwater runoff. These changes, in turn, increase erosion and degrade water quality. By promoting green infrastructure, it reduces, retains, and treats runoff at its source. This study investigates how roof substrate and vegetation affect rainwater retention. The investigated parameters are lightweight substrate ratio, substrate depth, precipitation and vegetation type. This study was done in Anantapur district, Andhra Pradesh, India. A planting box was placed on the roof of a building to simulate a green roof and the required conditions were mimicked. The experimental results indicate that precipitation, substrate depth, substrate ratio and vegetation type affect the rainwater retention capacity of green roofs. The rainwater retention rate is inversely proportional to precipitation intensity. According to the water retention capacity of various plants, black gram and schefflera arboricola have been chosen as they retain more water. Of the total amount of rainwater retained the substrate accounts for 77–98% and vegetation accounts for 2–23%. In the sub-tropical region, the green roof water retention rate is roughly 30% of the total storm precipitation (160 mm). Thus, using a green roof is an effective strategy for managing urban stormwater. This study also investigates calculating the average cost of green roofs and difficulties due to the number of variables. The final result a deeper green roof has been designed and high substrate is needed because black gram has been grown.

This study proposes a framework and a process promoting creation of sustainable jobs and businesses in rural, arid and semi-arid agricultural conflict zones of Sub Saharan Africa, focusing on Somalia's societal stabilization and conflict mitigation. This task requires developing risk-reducing measures for infrastructure and service delivery in rural, post-conflict zones. Literature reviews identified two economic growth theories rooted in sustainability concepts for localized, pro-poor development. Ecological Economics Theory (EET) and Endogenous Growth Theory (EGT) are the philosophical bases establishing investment priorities. Additional research regarding Somali culture, key conflict factors, and potential business opportunities, provides an understanding of salient facts in Somalia's on-going, 27-years of war and potential culturally acceptable development pathways. Informal sources, Somali and non-Somali, were consulted to further identify and verify potential avenues for economic growth, sustainability, educational opportunities, allowing Somalia to emerge from the strife it has endured. Visits to Somalia and Somaliland confirmed that livestock, its products and related requirements, are key components for economic growth and job creation. Investigation, via pilot testing and case studies, was undertaken of technologies with potential to improve productive capacity and disrupt existing value chains. Initial framework elements were evaluated for job and business creation, through unstructured, semi-structured interviews, and questionnaire of Somali officials, and Somali and non-Somali conflict zone development practitioners. The pilot test used a small sample size and is a limitation of this work. Findings from the literature review, informal discussions, and the pilot test are synthesized into the framework presented in Chapter 5. The framework proposes development of an innovative, disruptive, and scalable business model that facilitates the simultaneous implementation of renewable energy production. It targets education for the livestock and agroforestry industry of Somalia, improving job and business opportunities. The model proposes modification of used shipping containers for the creation of modular elements, to satisfying infrastructural building components to initiate skills practice, job, and business growth.
Doctor of Philosophy
The wars and conflicts of various types in Africa have made the continent poorer and prevented development in many countries. One of the major, and seemingly intractable conflict locations, is Somalia located in the East Horn of Africa (EHA). This research provides an understanding of salient facts in Somalia's 27 years of war by examining culture and key conflict factors. The objective of this assessment is to identify potential culturally acceptable pathways that will lead to business opportunities and development as a means of conflict mitigation. The improvement of job opportunities for youth is viewed as a means to offset the current participation in the ongoing conflict. Somali and non-Somali sources were consulted to identify and verify avenues for economic growth, sustainability, and educational opportunities. Visits to Somalia and Somaliland confirmed that livestock, and related products, are key components for development and job creation. Technologies with potential to improve productive capacity and disrupt existing value chains were also evaluated. Findings from informal discussions and a pilot test of a proposed framework are presented. The framework identifies elements for development of an innovative, disruptive, and scalable business model that facilitates the implementation of renewable energy production. In addition, it targets education for the livestock and agroforestry industries, improving job and business opportunities.

Studies have been completed into the spectral response of alkaline and other ultramafic rocks from arid and semi-arid regions. To date these rocks have not been investigated spectrally in a systematic fashion using the latest field and airborne imaging spectrometers. The objective was to determine how spectral geological techniques could be used to locate these rock types when they are exposed, weathered and reduced to residual soil. The data used in this study were spectra obtained from field spectrometers (PIMA and GER IRIS MkIV) and airborne scanners (GEOSCAN MkII, GER IS and HyMap). These data were gathered at four sites within Australia. The data processing software packages used for the analyses were commercially available image processing systems (is S'600and ENVI) and a modified version of PIMAVIEW for processing spectra. Spectra were measured, in the field and the laboratory, of alkaline and other ultramafic rocks to determine if they had diagnostic spectral absorption features. These studies demonstrated that there are diagnostic spectral absorption features common to alkaline and other ultramafic rocks including dunite, peridotite and serpentinite. The diagnostic spectrum in the SWIR2 region (2000nm to 2500nm) has absorption features located near 2300nm and 2380nm and results from Mg-OH bearing minerals including serpentine, talc and phlogopite. The VNIR spectra of these rocks also have distinct absorption features, but since these are caused by minerals that are common to a variety of rocks and soils, they have not been considered in this study. When weathered under arid and semi-arid conditions, ultramafic rocks break down into smectite clays, primarily saponite. Saponite has a similar spectral signature to the primary Mg-OH bearing minerals. Further weathering and removal of magnesium results in saponite altering to kaolinite and then to opaline silica. These minerals may occur in residual soils derived from ultramafic rocks. Spectral investigation of mixtures of saponite and other minerals showed that there are linear changes the absorption features of spectra, depth, wavelength and shape, as the proportion of saponite to other minerals varies. The ability to identify ultramafic rocks from the distribution of their diagnostic spectra was confirmed by analysing data obtained from surface samples and airborne scanners. The coincidence of results obtained from field studies and airborne scanner data signifies that data acquired remotely are as useful as spectra obtained in the field, for mapping the extent of ultramafic rocks. Present and past imaging systems have been investigated to determine the specifications required to suit this application. These investigations included sampling the spectra of ultramafic and background rocks with the band pass characteristics of various instruments. The signal-to-noise ratio that is required of scanner data to ensure it is useable was also studied. These studies indicated a specification for data of at least eight and preferably, thirty two channels in the SWIR2 (between 2000nm and 2500nm) obtained with a signalto-noise ratio in excess of 200: 1, ideally 400: 1 at 2200nm. Scanners producing data with these specifications can be used to locate ultramafic rocks from their spectral signature, whether exposed or covered by residual soils in a variety of geological environments. The success of applying these techniques will however depend on the spectral contrast between ultramafic rocks and their backgrounds. Rocks that produce Mg-OH bearing minerals or have near 2300nm absorption can result in areas being mistakenly identified as containing alkaline and other ultramafic rocks. However, in this study it was demonstrated that carbonate soils and rocks that have a near 2300nm absorption feature can be spectrally distinguished from alkaline ultramafic derived saponite using HyMap scanner data. In South Australia dolomite appears to have altered to saponite at surface but kimberlites in the area can still be detected by processing HyMap scanner data with spectral as opposed to conventional image processing techniques.

Continued expansion of the gold and nickel mining industry in Western Australia during recent years has led to disturbance of larger areas and the generation of increasing volumes of waste rock. Mine operators are obligated to rehabilitate all disturbed surfaces and reconstructed landforms, and considerable effort and expense is now applied to the achievement of this objective. Associated with increasing rehabilitation effort is the requirement to accurately judge rehabilitation success through the development of completion criteria. Completion criteria are rehabilitation performance objectives set as conditions of approval for each stage of rehabilitation and for the project as a whole. They provide standards against which the success of rehabilitation can be measured, or more broadly the point at which responsibility for rehabilitation is complete. The current research project tackles the development of completion criteria by investigating ecosystem function within a variety of rehabilitation trials at four mine sites located in arid and semi-arid Western Australia, and also within surrounding 'natural' vegetation complexes undisturbed by mining, termed analogue sites. Six specific objectives were identified as part of the study: 1. To establish an appropriate end point land use for each mine site where field trials were established; 2. To examine long-term ecosystem development through the assessment of revegetation at a variety of rehabilitation sites; 3. To examine functional components within analogue communities and make appropriate comparisons with rehabilitation trials; 4. To record the potential reproductive capacity of revegetation progeny, and determine how this relates to ecosystem function;5. To provide a better understanding of ecosystem function by investigating the relationship between state factors, interactive controls, and ecosystem processes at rehabilitation and analogue sites; and 6. To develop a methodology for establishing realistic environmental completion criteria at mine sites situated in arid and semi-arid Western Australia. Field trials were established at four mine sites located within three subtly different bioclimatic zones that extend through the arid / semi-arid shrubland belt of Western Australia; Northeastern Goldfields (Granny Smith Gold Mine, Sunrise Dam Gold Mine), Eastern Goldfields (Black Swan Nickel Mine), and Northeastern Wheatbelt (Westonia Gold Mine). 1 The re-establishment of a self-sustaining vegetation cover integrated with the surrounding ecosystem, was the common end land use objective at the four mine sites selected for this study. For three sites located in the Northeastern Goldfields and Eastern Goldfields of Western Australia, sheep were grazed on surrounding rangeland; the fourth site located in the Northeastern Wheatbelt of Western Australia, and was surrounded by Crown Land. 2 To better understand ecosystem function, the dynamic behaviour and interaction of plant biodiversity parameters was monitored regularly at 19 post-mining rehabilitation sites up to 11 years after direct seeding. For functional ecosystems, plant biodiversity parameters changed rapidly during the initial five years after seeding following predictable trends, after which time they remained within a relatively stable range.The stabilising of parameters over time was identified as a key indicator of rehabilitation success, however the point at which the parameters stabilised was influenced by numerous variables and was difficult to accurately predict. Prolific seed germination resulted in high seedling density during the initial growing season. Plant density then progressively decreased in response to competition, before stabilising within a range approximately five years after seeding. Revegetation cover was typically low during the first growing season, increasing rapidly there after before also stabilising in line with plant density. Maximum species richness was generally achieved during the first and second year when annual Atriplex species were prominent. Perennial Atriplex species established more slowly during the early stages of revegetation development, but eventually replaced the annual component as the dominant taxa. Perennial Maireana species required up to three years before germinating in the field and establishing themselves in the revegetation; in many cases they replaced perennial Atriplex as the prominent taxa. The presence or absence of cyclonic rainfall during the first growing season was a major determinant of the ecosystem trajectory, controlling revegetation structure and composition. The germination and successful establishment of hard seeded species, including Acacia and Senna, was reliant on heavy summer rainfall during the early stages of ecosystem development to break seed dormancy and extend the length of the first growing season. This provided an important competitive advantage against faster growing Atriplex species, which possessed greater drought tolerance.The intensity of summer rainfall was also beneficial in leaching surface salts from the upper profile and hence, reducing salinity within the rooting zone. In the absence of heavy summer rainfall during the first growing season, the establishment of a low chenopod dominated vegetation cover was favoured, total species richness for the rehabilitation tended to be lower, and the variety of plant life forms was restricted to low and mid stratum shrubs. Increasing water stress resulted in progressively higher rates of local species extinction, with fewer taxa possessing the drought tolerance adaptations required to survive. For established revegetation, cyclonic rainfall increased productivity (as measured by % foliage ground cover) and stimulated the establishment of new taxa, which in many cases were brought in from adjacent unmined vegetation complexes (analogue sites). While the benefits of summer cyclonic rainfall were undoubtedly important to ari and semi-arid ecosystems, the occurrence of drought was also important in buffering the ecosystem against large-scale change by acting as a negative feedback to constrain cumulative productivity. Parent waste rock material varied considerably between rehabilitation sites, affecting the soil resource supply and associated functional components. Extreme salinity was a typical limitation of the rehabilitation medium, reducing the variety of salt tolerant species and favouring annual Atriplex during the early stages of ecosystem development. The cover of annual species present during early stages of ecosystem development contributed to decreasing salinity in the plant rooting zone, by reducing surface temperature and hence capillary rise of salts during summer months.Annual Atriplex species were replaced by perennial Atriplex in line with decreasing surface salinity. Fundamental to successful revegetation of the post-mining rehabilitation site was the requirement that reconstruction and contouring focus on maximising water retention and reducing salinity within the upper soil profile. Once the initial vegetation community established and plant parameters became relatively stable, change continued to occur, albeit slowly. One factor contributing to this change was the immigration rate of biota from adjacent revegetation or more commonly from surrounding analogue complexes. Linking rehabilitation areas to surrounding functional ecosystems ensured the movement of plants and animals, and ultimately increased the rate of recovery. The sustainability of post-mining rehabilitation was enhanced where these links were established early, allowing for the provision of additional seed and the migration of displaced species. The life cycle pattern of keystone species in the revegetation was found to be an important determinant in long-term sustainability of the plant cover, particularly for chenopod shrublands where one species was typically dominant. The senescence and death of large numbers of a dominant revegetation species together, had the ability to significantly alter the revegetation structure and composition. The impact for rehabilitation where a number of dominant taxa co-exist was less pronounced. Thus it follows that a minimum level of species richness was important to long-term rehabilitation sustainability, as was the development of an age-class structure in the rehabilitation.The most common disturbances encountered at the rehabilitation trial sites were drought, overgrazing and weed infestation. All three disturbances decreased the plant biodiversity parameters measured. Ecosystem recovery following disturbance was dependent on effective rainfall, but occurred rapidly with plant parameters returning to pre-disturbance levels within one to two growing seasons. The recovery of plant biodiversity parameters followed the same trends identified at functional rehabilitation sites during the initial five years following direct seeding. 3 Assessment of plant biodiversity parameters occurred at 15 analogue sites supporting native vegetation undisturbed by mining. It was anticipated that data from analogue sites could be used as a 'reference' against which to compare developing rehabilitation. However, analogue vegetation complexes were less dynamic in comparison to rehabilitation sites. Minor seasonal changes were recorded for plant biodiversity parameters, but overall annual change was minimal. Significant and sudden changes within analogue communities only occurred following disturbance, such as severe overgrazing, and recovery to pre-disturbance levels was rapid following the removal of the disturbance and return of effective rainfall. A major difference between rehabilitation and analogue sites related to their age. Rehabilitation sites were 'juvenile systems' assessed against a time frame much shorter than had been required for natural processes to achieve the developmental state represented at analogue sites.Hence, it was important not to model one specific analogue site too closely, but instead model the desired revegetation structure and species composition on a variety of local analogue complexes occurring in parent materials 'matched' closely to those of the rehabilitation site. Data from analogue sites should be utilised extensively during rehabilitation planning, but cautiously when interpreting the rehabilitation outcome. For mine sites in arid and semi-arid Western Australia, the application of specific numeric targets for plant biodiversity parameters as a measure of rehabilitation success was not recommended. A number of factors and controls in the developing ecosystem together determined the rehabilitation outcome. These factors were site and time specific; minor changes in any number of variables led to significantly different rehabilitation outcomes, making them difficult to accurately predict. 4 Quality and germination testing confirmed progeny seed from a number of rehabilitation trials was of similar or higher viability than the maternal seed originally sown. This was further confirmed by field responses at trials in the Northeastern Goldfields one year after the 1994 drought, when elevated plant density was recorded following the return of above average rainfall. The ability of rehabilitation to show an immediate response to rainfall following a seven-month drought, and for vegetation parameters to subsequently recover to pre-disturbance levels within one to two years, provided an indication that the revegetation cover was resilient. The relationship between plant production and rainfall was dependent on a 'carryover' effect between seasons or following drought years, and 'pulses' mediated, for instance, by the amount of seed in the soil store.The 'reserve' component in and ecosystems was responsible for both the memory of the system between pulses and for its long-term resilience. 6 The analysis of time series data collected from 19 rehabilitation trials emphasized the importance of planning and implementation of best practice techniques to subsequent rehabilitation success, and reinforced the difficulty associated with accurately predicting the final rehabilitation outcome. The large spatial heterogeneity of undisturbed vegetation complexes across the landscape of arid and semi-arid Western Australia, provided the foundation on which site-specific rehabilitation scenarios could be modelled, albeit with caution. The translation of data into useful completion criteria was dependent on the realisation that successful rehabilitation requires the implementation of best practice rehabilitation techniques, as determined by technically prescriptive (design) based standards, as much as the identification of a successful rehabilitation outcome, as determined by performance (outcome) based standards. With this in mind, completion criteria were developed as part of a robust theoretical framework incorporating the larger mine plan, and were not simply based on numbers generated as stand-alone performance standards. The broad methodology generated could be adopted by any mine site across the mining industry, however the criteria and, more specifically, the standards for each criterion should always remain site specific.The methodology designed for developing completion criteria has been addressed in three stages: 1. Planning, 2. Operational and Monitoring, and 3. Post-Mining Hand-Over. Within each stage three parameters are addressed: 1. Criteria, 2. Process, and 3. Standard. 'Planning' is the most important stage in the development of completion criteria. It is the stage when an appropriate end land use is determined, analogue sites are assessed, a rehabilitation plan developed along with specified design standards ensuring implementation of best practice techniques, and a process of risk assessment implemented. The 'Operational Monitoring Stage' focuses on rehabilitation success during the period of ecosystem development. This stage is concerned largely with rehabilitation monitoring, from which performance standards can be developed to gauge rehabilitation success for specific periods during revegetation development. The initial task in Stage 2 is to ensure all aspects of the rehabilitation plan have been implemented as specified in Stage 1, and meet agreed design standards. The final stage of the completion criteria process, 'Post Mining Hand Over', is to ensure the rehabilitated site is safe, and able to successfully revert to the end land use.While plant biodiversity parameters formed the focus of the current study, a variety of other functional ecosystem components may also make sound assessment criteria for determining rehabilitation success. Increasing the knowledge base for other functional components in arid and semi-arid ecosystems would further increase the ability to accurately determine rehabilitation success.

The aim of the study is two fold: first, the study analyzes the formation of the urban heat island (UHI) in eight different cities in arid and semi-arid region. The analysis is based on land cover / land use (LCLU) classification (urban, green, and bare areas). Second, the study synthesizes the mitigation strategies to reduce the land surface temperature (LST) and hence the UHI effects in the arid and semi-arid cities. The study found that the bare areas have the highest mean LST compared to the urban and green areas. Furthermore, the study found that the LST varies in each of the LCLU categories and hence some areas of the three categories have LST lower or higher than the other categories and hence not always one category has the highest LST compared to the other categories. The outcomes of this study may have key implications for urban planners seeking to mitigate urban heat island effects in arid and semi-arid urban areas.

The main objectives were (1) to develop, implement and validate control procedures that would make it possible to maintain year-round air temperature and humidity at levels suitable for crop cultivation in greenhouses operating in arid and semi-arid regions and (2) to investigate the influence of the operational flexibility of the fogging system on the performance of the system. With respect to the development of climate controllers, we developed a new control approach according to which ventilation is used to maintain the enthalpy of the greenhouse air and fogging is used to adjust the humidity ratio inside the greenhouse. This approach is suitable mostly for greenhouses equipped with mechanized ventilation, and in which the air exchange rate can be controlled with enough confidence. The development and initial validation of the controllers were performed in a small experimental greenhouses located at the Agricultural Research Organization and very good tracking were obtained for both air temperature and relative humidity (maximum mean deviations over a 10-min period with constant setpoints lower than 2.5oC and 5% relative humidity). The robust design approach used to develop the controllers made it possible to transfer successfully these controllers to a much larger semi-commercial greenhouse located in the much drier Arava region. After only minimal adjustments, which did not require lengthy dedicated experiments, satisfactory tracking of the temperature and humidity was achieved, with standard deviation of the tracking error lower than 1oC and 5% for temperature and relative humidity, respectively. These results should help promote the acceptance of modern techniques for designing greenhouse climate controllers, especially since given the large variety of greenhouse structures (shape, size, crop system), developing high performance site-specific controllers for each greenhouse is not feasible. In parallel to this work, a new cooling control strategy, which considers the contribution of humidification and cooling from the crop, was developed for greenhouses equipped with natural ventilation. Prior to the development of the cooling strategy itself, three evapotranspiration models were compared in terms of accuracy and reliability. The cooling strategy that has been developed controls the amount of fog introduced into the greenhouse as well as the percentage of vent openings based on the desired vapor pressure deficit (VPD) and enthalpy, respectively. Numerical simulations were used to compare the performance of the new strategy with a constant fogging rate strategy based on VPD, and on average, the new strategy saved 36% water and consumed 30% less electric energy. In addition, smaller air temperature and relative humidity fluctuations were achieved when using the new strategy. Finally, it was demonstrated that dynamically varying the fog rate and properly selecting the number of nozzles, yields additional water and electricity savings.