Controlling Disk Contention for Parallel Query Processing in Shared Disk Database Systems

Shared Disk database systems offer a high flexibility for parallel transaction and query processing. This is because each node can process any transaction, query or subquery because it has access to the entire database. Compared to Shared Nothing, this is particularly advantageous for scan queries for which the degree of intra-query parallelism as well as the scan processors themselves can dynamically be chosen. On the other hand, there is the danger of disk contention between subqueries, in particular for index scans. We present a detailed simulation study to analyze the effectiveness of parallel scan processing in Shared Disk database systems. In particular, we investigate the relationship between the degree of declustering and the degree of scan parallelism for relation scans, clustered index scans, and non-clustered index scans. Furthermore, we study the usefulness of disk caches and prefetching for limiting disk contention. Finally, we show the importance of dynamically choosing the degree of scan parallelism to control disk contention in multi-user mode

Smithsonian Biodiversity Outreach Program in Gabon

This report was prepared for the Smithsonian Institution\u27s Monitoring and Assessment of Biodiversity Program (MAB). Our project created lesson plans regarding ecological problems in Gabon and the research of the Smithsonian to mitigate these problems. The report describes the methods used in creating the lesson plans, and an analysis of the structure, content, activities developed, and recommendations for future lesson plans. The implementation of these lesson plans will provide the Gabonese youth awareness of the ecological issues of their country as well as knowledge of Smithsonian Institution research

Earthworm, microbial biomass, and leaf litter decay responses after invasive honeysuckle shrub removal from urban woodlands.

Invasive species are one of the leading causes of biodiversity loss and their presence can significantly impact the structure and function of native ecosystems. In this dissertation, the impacts of the invasive honeysuckle shrub, Lonicera maackii, on exotic earthworm populations, leaf litter decay responses, and inorganic and organic nutrient pools in an urban woodland park are assessed. Chapter 1 provides a brief review of honeysuckle\u27s effects on forest ecosystems. Chapter 2 describes honeysuckle’s effects on exotic earthworm populations and the seasonal importance of macroinvertebrates to leaf litter decomposition in urban woodlands. This study revealed that L. maackii promoted higher exotic earthworm biomass and density and that macroinvertebrates actively decomposed litter across all seasons. In Chapter 3, the effect of macroinvertebrate activity (including earthworms) on the decomposition and nitrogen dynamics of honeysuckle and sugar maple leaf litter mixtures during the late winter were assessed to determine if they contribute to honeysuckle success. Without macroinvertebrates, litter mixtures imported nitrogen in late winter, reducing nitrogen availability to plants. With macroinvertebrates, nitrogen release coincided with honeysuckle leaf expansion in late winter. Since no other woody plants exhibited such early leaf expansion phenology, honeysuckle is in an advantageous position to take up this nitrogen pulse. The results of Chapters 2 and 3 together provide strong support for a positive feedback between honeysuckle and soil processes and the existence of invasional meltdown between earthworms and honeysuckle. In Chapter 4, the temporal dynamics of inorganic, organic, and microbial biomass C and N pools were assessed with respect to honeysuckle presence and time since honeysuckle removal. The results from this analysis indicated that neither honeysuckle shrub presence nor time since removal were important factors in determining inorganic, organic, or microbial nutrient pools. Percent bare soil and soil moisture content were the most common factors predicting soil nutrient dynamics during each season. Overall, these results suggest that honeysuckle and exotic earthworms may form an ‘invasional meltdown’ leading to increasing rates of invasion and/or increased impacts on native communities and ecosystems. However, other factors may be more important in determining soil nutrient dynamics than L. maackii presence alone

Mining a Small Medical Data Set by Integrating the Decision Tree and t-test

[[abstract]]Although several researchers have used statistical methods to prove that aspiration followed by the injection of 95% ethanol left in situ (retention) is an effective treatment for ovarian endometriomas, very few discuss the different conditions that could generate different recovery rates for the patients. Therefore, this study adopts the statistical method and decision tree techniques together to analyze the postoperative status of ovarian endometriosis patients under different conditions. Since our collected data set is small, containing only 212 records, we use all of these data as the training data. Therefore, instead of using a resultant tree to generate rules directly, we use the value of each node as a cut point to generate all possible rules from the tree first. Then, using t-test, we verify the rules to discover some useful description rules after all possible rules from the tree have been generated. Experimental results show that our approach can find some new interesting knowledge about recurrent ovarian endometriomas under different conditions.[[journaltype]]國外[[incitationindex]]EI[[booktype]]紙本[[countrycodes]]FI

Maakasutusmuutuste mõju maapiirkondade maastikulisele ja bioloogilisele mitmekesisusele

Land use changes have substantial impact on rural landscape and biological diversity. The thesis analyses the changes in rural landscapes that have occurred in Hiiumaa since 1950s focusing, in particular, on the transformation of open and half-open semi-natural farmlands. The correlation between the agricultural land use dynamics and biota is analysed from both ecological aspects, i.e., how the land use changes in recent decades have influenced the local numbers and distribution of autumn staging Eurasian Cranes (Grus grus) in Estonia, and, from the viewpoint of bioindication, i.e., whether certain soil bioindicators can be used for evaluating the effectiveness of agri-environmental (AE) measures as well as the level of human pressure at field level. In addition, the spatial distribution of topic-based monitoring networks is analysed to combine and integrate data from different monitoring sets and to achieve more coherent geographical coverage of monitoring data for the surveillance of agricultural landscapes. The detailed spatial land use analysis in Hiiumaa enabled the exploration of the transformation of the former diverse and mosaic land use patterns that are characteristic of extensive agriculture to more uniform patterns of intensive agriculture. The greatest change in landscape pattern took place by the 1980s as a result of the intensification of farming, land reclamation and marginalisation. From 1956 to 1998 the area of agricultural lands decreased mainly because of semi-natural grasslands by approximately 43%, and the area of forests increased by approximately 44%. The remarkable changes in agricultural land use intensity, which included a sharp decline in the 1990s and a remarkable revival since 2000, have not yet caused any significant changes in developed simplified landscape pattern. The study enabled to elucidate the origin of the larger ameliorated field systems and to track the transformation of the once widespread open and half-open semi-natural grasslands to forests and other land use types. For instance, by 1998, only approximately 3% of pastures and 12% of grasslands that were present in 1956 were maintained and classified as open grasslands. The study also enabled to analyse the changes in wooded meadows and pastures. The area of half-open land use types, such as grasslands and pastures that were sparsely covered with trees and shrubs, decreased significantly by more than 10 times from 1956 to 1984. The slight increase from 1984 to 1998 is most likely related to the abandonment of agricultural areas. The simplification of land use patterns has controversial impacts to biota. The disappearance of traditional land use patterns and the sharp decline in half-open farmlands has decreased the spread of species-rich habitats; however, the huge agricultural areas (cultivated grasslands and cereal fields) have become important feeding and staging habitats for migrating birds. The following study found significant correlations between the cropping areas of certain field crops and the count numbers of autumn staging Eurasian cranes. In Hiiumaa the correlation was strongest with the cropping area of winter rye (rs = 0.58, p < 0.05, n = 21) and winter wheat (rs = 0.58, p < 0.05, n = 21) and in Matsalu with the cropping area of all cereals combined (rs = 0.56, p < 0.05, n = 28). Then correlations between land use change and biota were also studied from the viewpoint of bioindication. The pilot project, that was performed for testing the effects of AE measures to soil biota, could not detect statistically significant differences between the AE pilot areas and their reference areas in the same regions. The study demonstrated that the short-term application of AE measures cannot have significant effects on soil biota, but the soil biota indicators could have considerable potential as early indicators of soil degradation or improvement when integrated in long-term monitoring programs of agricultural landscapes. The study found statistically significant (p < 0.05) differences in the hydrolytical activity of the microbial community between Palamuse (intensive) and Saaremaa (extensive) pilot areas. However, in this study, it was impossible to separate the impacts of farming intensity and contrasting natural conditions on soil biota. For improvement the monitoring concept for agricultural landscapes and for integrating complementary monitoring data, the distribution of different independently developed topic-based monitoring networks were analysed by Estonian landscape regions, CORINE land cover classes and soil types. The patterns of monitoring networks were studied by neighbourhood analysis, characterised by the nearest neighbourhood index and Ripley’s K-function, and the density analysis in the search radius of 50 km. The analysis covered in total 14 different landscape, biodiversity and environmental monitoring sub-programs.Maakasutusmuutustel on oluline mõju maapiirkondade maastikulisele ja bioloogilisele mitmekesisusele. Käesolev doktoritöö analüüsib viimasel poolsajandil (1956–2005) Hiiumaa põllumajandusmaastikus toimunud muutusi, keskendudes eeskätt muutustele avatud ja poolavatud maakattetüüpides. Käsitlemist leiavad ka põllumajandusliku maakasutuse ja elustiku vahelised seosed, s.o viimaste aastakümnete maakasutusmuutuste mõju sügisesel läbirändel Eestis peatuvate sookurgede (Grus grus) arvukusele ja mulla bioindikaatorite sobivus põllumajandus- ja keskkonnameetmete tõhususe ning inimmõju taseme hindamiseks. Põllumajandusmaastiku seirekontseptsiooni ja -võrgustiku arendamiseks ning täiendavate seireandmete lõimimiseks analüüsiti Eesti teemapõhiste seireprogrammide andmestike territoriaalset jaotumust erinevate maastikutunnuste järgi. Detailne maastikuanalüüs võimaldas uurida traditsioonilise, s.o ekstensiivsele põllumajandusele iseloomuliku mitmekesise ja mosaiikse maakasutusmustri olulist lihtsustumist ning polariseerumist Hiiumaal. Suurim muutus maastikumustris leidis aset juba 1980. aastateks, peamiselt uute intensiivseks põllumajanduseks sobivate maade raadamise ja sobimatute marginaliseerimise tõttu. Ajavahemikul 1956–1984 vähenes põllumajandusmaa valdavalt looduslikku tüüpi rohumaade arvel kokku umbes 43%, samal ajal suurenes metsade pindala umbes 44%. Järgnevad suured muutused põllumajandusmaa kasutuses: järsk vähenemine 1990. ja elavnemine 2000. aastatel ei ole seevastu toonud kaasa suuri muutusi juba väljakujunenud lihtsustunud maastikumustris. Uuring aitas selgitada praeguste põllumassiivide päritolu ning kunagi laialt levinud heina- ja karjamaadega toimunut. Näiteks 1956. aasta heina- ja karjamaadest oli 1998. aastaks üle poole kaetud metsaga, kusjuures ainult 3% karjamaadest ja 12% heinamaadest olid säilitanud oma varasema ülesande. Valitud metoodika võimaldas kaudselt hinnata ka muutusi liigirikaste puisniitude ja -karjamaade levimuses. Kui 1956. aastal olid poolavatud põllumajandusmaad, s.o nii puude kui ka põõsastega hajusalt kaetud heina- ja karjamaad levinud kokku 7492 hektaril, siis 1984. aastaks oli taoliste maade pindala kahanenud enam kui kümme korda 695 hektarile. 1998. aastaks oli poolavatud alade pindala suurenenud 1072 hektarile, kuid seda peamiselt hüljatud põllumajandusmaade renaturaliseerimise arvelt. Maastikumuutuste mõju elustikule on vastuoluline. Traditsioonilise maakasutusmustri kadumine ja poolavatud põllumajandusmaade oluline vähenemine on kahandanud liigirikaste elupaigatüüpide levimust, samas on suured põllumassiivid saanud tähtsaks toitumis- ja peatuspaigaks paljudele läbirändavatele linnuliikidele. Järgneva uuringuga leiti statistiliselt olulisi korrelatsioone teatavate põllukultuuride külvipindade ja sügisel Eestis peatuvate sookurgede loendusandmete vahel, kusjuures Hiiumaal oli nimetatud seos kõige tugevam talirukki (rs = 0,58, p < 0,05, n = 21) ja talinisu (rs = 0,58, p < 0,05, n = 21) külvipindadega ning Matsalus kõigi teraviljade (rs = 0,56, p < 0,05, n = 28) koondkülvipinnaga. Maakasutusmuutuste ja elustiku vahelisi seoseid uuriti ka bioindikatsiooni aspektist. Katseprojekt, mis viidi läbi põllumajandus- ja -keskkonnameetmete mõju uurimiseks mullaelustikule, ei tuvastanud statistiliselt olulisi erinevusi katsealade ja võrdlusalade vahel ning näitas ilmekalt, et lühiajaline põllumajandus- ja keskkonnameetmete rakendamine ei avalda mullaelustikule suurt mõju. Juhtuuring tuvastas statistiliselt olulise (p < 0,05) erinevuse mullamikroobide hüdrolüütilises aktiivsuses intensiivselt ja ekstensiivselt majandatud katsealade vahel. Arvestades katsealade kontrastseid loodustingimusi Palamusel Jõgevamaal ja Kihelkonna-Lümandus Saaremaal, tulenes nimetatud erinevus mitte ainult majandamise erinevast intensiivsusest, vaid suurel määral ka erinevate loodustingimuste mõjust, kuid selle uuringu raames ei olnud võimalik nende kahe peamise teguri mõju eristada. Uuring näitas, et põllu tasemel võivad mulla teatud bioindikaatorid (vihmaussikoosluste parameetrid ja mullamikroobide hüdrolüütiline aktiivsus) anda tähtsat teavet mulla seisundi ja inimmõju kohta, kui need on lõimitud pikaajalisse põllumajandusmaastike seiresse. Põllumajandusmaastiku seirekontseptsiooni arendamiseks ja sellesse täiendavate seireandmete lõimimiseks analüüsiti Eesti teemapõhiste seireprogrammide andmestiku territoriaalset jaotumist erinevate maastikutunnuste, näiteks Eesti maastikurajoonide, CORINE maakattetüüpide ja mullatüüpide järgi. Seirevõrgustike ruumilist paiknemist iseloomustati ka naabrusanalüüsi, s.o lähimnaabruse indeksi ja Ripley K-funktsiooni ning tihedusnäitajate abil. Analüüs hõlmas kokku 14 erinevat maastiku-, elustiku- ja keskkonnaseire alamprogrammi.The doctoral studies and the publication of this thesis were supported by the Estonian University of Life Sciences and by the Doctoral School of Earth Sciences and Ecology created under the auspices of European Union Social Fund

Community Ecology and Sirex noctilio: Interactions with Microbial Symbionts and Native Insects

Sirex noctilio is an invasive woodwasp with a global distribution that feeds on the sapwood of pine trees. Wood-feeding in the basal Hymenoptera (sawflies) arose out of sequential adaptations to feeding on nutrient poor and digestively refractive internal plant organs (xylem). Symbiotic association with White-rot fungi are thought to aid overcoming nutritional and digestive barriers, including exceedingly low nitrogen (N) and refractory lignocellulosic polymers. In this dissertation I evaluate wood-feeding relative to nutrition, symbiosis and biotic resistance to invasion of exotic North American habitats in Sirex noctilio [Hymenoptera: Siricidae]. I evaluated nutrient relations within fungal mutualism using: 1) functional morphological analysis of insect feeding, 2) sterol molecules to determine diet sources and 3) metagenomic and isotopic analyses for discovery of novel microbial associates and their associated nutrient pathways. Nutritional constraints of wood feeding are potentially compounded by the presence of diverse fungal and insect communities as they divide the tree resource. I examined the role biotic resistance to Sirex and its fungal mutualist, Amylostereum, in North America using field and laboratory experiments. Morphological evidence supported a role for Amylostereum in external digestion of wood. Observational evidence confirmed Sirex larvae did not ingest wood biomass but preferentially extracted liquid substances via specialized structures of mandibles. Sterol analysis indicated plant compounds as the primary constituent of the diet, while metagenomic analysis of bacteria and their metabolic pathways showed a bacterial microbiome adapted to short chain plant polymers, starch and sugar metabolism. Stable isotopes suggested an additional symbiotic association with nitrogen fixing bacteria enriched the nitrogen deficient food substrate. These studies point toward herbivory with microbial supplementation of nutrients as a tri-partite relationship, pending conclusive identification of the bacterial symbiont for Sirex. Specific constraints of wood feeding by the Sirex-Amylostereum symbiotic complex were antagonized by intraguild predation and fungal competition in North America. Competition interfered with Amylostereum, while intraguild predation accounted for an additional 15% mortality of larval populations. This research describes the evolutionary role of microbial symbionts in wood-feeding in the Hymenoptera and the internal and external constraints to foraging this ubiquitous, yet nutrient poor food resource

The Relationship between Professional Development and Teacher Change in the Implementation of Instructional Strategies that Support Elementary Students\u27 Science Textbook Reading

This study examined the relationship between a series of professional development workshops and change in three rural elementary teachers’ science textbook reading instructional strategies. The analysis of the qualitative data indicates the degree of teacher change was related to several inner-related factors: (a) teaching experience, (b) teacher perceptions of self, (c) mode of content delivery, and (d) teacher beliefs. Two teachers with the greatest longevity of teaching experience had previously established instructional strategies and modes of content delivery which did not emphasize student textbook reading skills. Their modes of content delivery were related to their self- perceptions as “science teachers” who provided learning experiences for their students outside of reading the science textbook. The main mode of content delivery for the teacher with the least amount of experience was her students’ reading and comprehending the textbook. This teacher demonstrated the most change in science textbook reading strategy implementation by utilizing a package of informational text reading strategies and gradually releasing the control of strategy application to her students

Climate Change and Environmental Sustainability-Volume 2

Our world is facing many challenges, such as poverty, hunger, resource shortage, environmental degradation, climate change, and increased inequalities and conflicts. To address such challenges, the United Nations proposed the Sustainable Development Goals (SDG), consisting of 17 interlinked global goals, as the strategic blueprint of world sustainable development. Nevertheless, the implementation of the SDG framework has been very challenging and the COVID-19 pandemic has further impeded the SDG implementation progress. Accelerated efforts are needed to enable all stakeholders, ranging from national and local governments, civil society, private sector, academia and youth, to contribute to addressing this dilemma. This volume of the Climate Change and Environmental Sustainability book series aims to offer inspiration and creativity on approaches to sustainable development. Among other things, it covers topics of COVID-19 and sustainability, environmental pollution, food production, clean energy, low-carbon transport promotion, and strategic governance for sustainable initiatives. This book can reveal facts about the challenges we are facing on the one hand and provide a better understanding of drivers, barriers, and motivations to achieve a better and more sustainable future for all on the other. Research presented in this volume can provide different stakeholders, including planners and policy makers, with better solutions for the implementation of SDGs. Prof. Bao-Jie He acknowledges the Project NO. 2021CDJQY-004 supported by the Fundamental Research Funds for the Central Universities. We appreciate the assistance from Mr. Lifeng Xiong, Mr. Wei Wang, Ms. Xueke Chen and Ms. Anxian Chen at School of Architecture and Urban Planning, Chongqing University, China