24,757 research outputs found

    Treatment of fractured concrete via microbially induced carbonate precipitation : from micro-scale characteristics to macro-scale behaviour

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    The development of techniques for concrete repair will reduce environmental impacts associated with concrete usage by extending the lifespan of existing structures. This study investigates microbially induced carbonate precipitation (MICP) for treating fractured concrete. Our results demonstrate the excellent penetrability of MICP with precipitates well-distributed along core length. Some individual treatment cycles resulted in ~one order of magnitude reduction in core permeability. Treatment efficiency is shown to be dependent on fracture network characteristics, i.e. number of fractures, fracture orientation, initial hydraulic aperture. Furthermore, bridging of precipitates across fracture surfaces resulted in a recovery of 26-50% of initial tensile strength

    Prediction of recurrence after chemoradiotherapy

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    We retrospectively assessed whether magnetic resonance imaging (MRI) radiomics combined with clinical parameters can improve the predictability of out-of-field recurrence (OFR) of cervical cancer after chemoradiotherapy. The data set was collected from 204 patients with stage IIB (FIGO: International Federation of Gynecology and Obstetrics 2008) cervical cancer who underwent chemoradiotherapy at 14 Japanese institutes. Of these, 180 patients were finally included for analysis. OFR-free survival was calculated using the Kaplan–Meier method, and the statistical significance of clinicopathological parameters for the OFR-free survival was evaluated using the log-rank test and Cox proportional-hazards model. Prediction of OFR from the analysis of diffusion-weighted images (DWI) and T2-weighted images of pretreatment MRI was done using the least absolute shrinkage and selection operator (LASSO) model for engineering image feature extraction. The accuracy of prediction was evaluated by 5-fold cross-validation of the receiver operating characteristic (ROC) analysis. Para-aortic lymph node metastasis (p = 0.003) was a significant prognostic factor in univariate and multivariate analyses. ROC analysis showed an area under the curve (AUC) of 0.709 in predicting OFR using the pretreatment status of para-aortic lymph node metastasis, 0.667 using the LASSO model for DWIs and 0.602 using T2 weighted images. The AUC improved to 0.734 upon combining the pretreatment status of para-aortic lymph node metastasis with that from the LASSO model for DWIs. Combining MRI radiomics with clinical parameters improved the accuracy of predicting OFR after chemoradiotherapy for locally advanced cervical cancer

    Winter mortality of a passerine bird increases following hotter summers and during winters with higher maximum temperatures

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    Climate change may influence animal population dynamics through reproduction and mortality. However, attributing changes in mortality to specific climate variables is challenging because the exact time of death is usually unknown in the wild. Here, we investigated climate effects on adult mortality in Australian superb fairy-wrens (Malurus cyaneus). Over a 27-year period, mortality outside the breeding season nearly doubled. This nonbreeding season mortality increased with lower minimum (night-time) and higher maximum (day-time) winter temperatures and with higher summer heat wave intensity. Fine-scale analysis showed that higher mortality in a given week was associated with higher maxima 2 weeks prior and lower minima in the current fortnight, indicating costs of temperature drops. Increases in summer heat waves and in winter maximum temperatures collectively explained 62.6% of the increase in mortality over the study period. Our results suggest that warming climate in both summer and winter can adversely affect survival, with potentially substantial population consequences

    Seed certification and maize, rice and cowpea productivity in Nigeria: An insight based on nationally representative farm household data and seed company location data

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    Despite the potential importance of seed quality to agricultural productivity growth, many governments in sub-Saharan Africa lack the capacity to expand quality assurance systems even where there is expressed interest. This study aims to evidence the value of quality assurance systems with an analysis of efforts to produce and distribute certified seed in Nigeria. We assess the associations between quantities of certified seeds produced and spatial variations in production locations proxied by headquarter locations of seed companies producing certified seeds, on the one hand, with spatial variations in the use of certified seed, yields, and output at the farm level, on the other hand. Our analysis covers three crops that are important to food security in Nigeria: maize, rice, and cowpea. Our analysis integrates information on seed quantities produced and locations of seed companies with nationally representative panel data from a survey of farm households and spatially explicit rainfall and temperature data. We find a positive relationship between certified seed production in proximity to farm households and farm-level use of certified seeds, yields, and output, although this effect is diminishing at the margin. These diminishing marginal effects may be partly due to two factors. First, the yield gains from certified seeds tend to vary considerably within each state, suggesting that either quality issues persist in the seed supply chain or farmers are not using complementary inputs or appropriate management techniques when using quality seed. Second, it may be that as certified seed becomes more available to farmers, its use spreads from higher-return farms to lower-return farms, thereby diminishing the gains on the extensive margin. Although more rigorous assessments of causal effects and cost-effectiveness are needed to validate these findings, these results are consistent with the hypothesis that there are diminishing returns to seed quality assurance. Policymakers, regulators, and seed providers may benefit from identifying optimal, crop-specific target quantities or rates for certified seed production rather than aiming for certification of all seed produced in a market

    Regionale Versicherungsrisiken unter dem morbiditÀtsorientierten Risikostrukturausgleich: Detektion, Ursachen und Reformbedarf der Wettbewerbsbedingungen in der GKV

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    Der Risikostrukturausgleich (RSA) ist der finanzielle Ausgleichsmechanismus zwischen den Krankenkassen. Er beschreibt, wie die Gelder des Gesundheitsfonds, dem Risiko gerecht, zwischen den Krankenkassen zu verteilen sind. Es ist das vordergrĂŒndige Ziel des RSA die Möglichkeit der Selektion von guten und schlechten Risiken (Risikoselektion) durch die Krankenkassen zu verhindern. Ohne einen RSA sind neben einem Verstoß gegen das SolidaritĂ€tsprinzip (BVerfG, Rn. 162 (18.07.2005)) Effizienzverluste durch die Verschiebung des Wettbewerbes zwischen den Krankenkassen von QualitĂ€t auf Risikoselektion (z.B. die Attrahierung von jungen und gesunden Personen), zu befĂŒrchten. Die These, die in dieser kumulativen Dissertation untersucht wird, ist, dass das Merkmal der regionalen Herkunft der Versicherten geeignet ist, um gute Risiken von schlechten Risiken zu trennen und somit Anreize zur Risikoselektion bietet. Es wird argumentiert, dass die rĂ€umliche Autokorrelation von individuellen DeckungsbeitrĂ€gen ein geeignetes Maß ist, um Anreize zur regionalen Risikoselektion zu erkennen. Dabei steht das Argument im Vordergrund, dass neben absoluten Deckungsbeitragsunterschieden die ValiditĂ€t der Information „regionale Herkunft“ fĂŒr Risikoselektion entscheidend ist. Die zweite Fragestellung der Dissertation betrifft die Ursachen der regionalen Risiken fĂŒr Krankenkassen. Die Identifikation von Ursachen verfolgt dabei das Ziel zu begrĂŒnden, ob die Versicherungsrisiken, die mit der regionalen Herkunft assoziiert sind, gemĂ€ĂŸ des SolidaritĂ€tsprinzips durch die Gesamtheit der Versichertengemeinschaft zu tragen wĂ€ren. Drittens wird die geographisch gewichtete Regression auf die Aspekte des Risikostrukturausgleichs angepasst und ein Verfahren beschrieben, wie die Regression auf dem sehr umfangreichen Datensatz des RSA effizient umgesetzt werden kann. Nach einer langen Debatte unter Gesundheitsökonomen wurde fĂŒr das Ausgleichsjahr 2021 erstmals eine Regionalisierung im RSA vorgenommen. Den Einzelveröffentlichungen dieser Dissertation war es beschieden, am gesundheitsökonomischen Diskurs teilzuhaben und letztlich die EinfĂŒhrung der Regionalisierung im RSA begleitet zu haben.:1 Einleitung 1.1 SolidaritĂ€t und Wettbewerb in der GKV 1.2 Motivation der Arbeit und Einordnung in die Literatur 1.3 Forschungsfragen und Gang der Arbeit 2 Der Einfluss der RegionalitĂ€t auf den Versicherungswettbewerb 2.1 Der wettbewerbliche Ordnungsrahmen der GKV 2.2 Dysfunktionale Folgen eines regional unvollstĂ€ndigen RSA 2.3 Maßzahlen der wettbewerblichen NeutralitĂ€t des 3 RĂ€umliche Versicherungsrisiken im solidarischen Wettbewerb 3.1 SolidaritĂ€t im RSA 3.2 Ursachen fĂŒr regionale Risiken 3.3 Einnahmerisiko 3.4 Mengen- und Strukturrisiko 3.5 Preisrisiko 4 Abbildung von rĂ€umlichen Versicherungsrisiken im RSA 4.1 Die Funktionsweise des RSA zwischen 2009 und 2020 4.2 Das M2-Modell 4.3 Das GWR-Modell 4.4 Ein empirischer Vergleich der RegionalisierungsansĂ€tze 5 Fazi

    Digital Inclusion of the Farming Sector Using Drone Technology

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    Agriculture continues to be the primary source of income for most rural people in the developing economy. The world’s economy is also strongly reliant on agricultural products, which accounts for a large number of its exports. Despite its growing importance, agriculture is still lagging behind to meet the demands due to crop failure caused by bad weather conditions and unmanaged insect problems. As a result, the quality and quantity of agricultural products are occasionally affected to reduce the farm income. Crop failure could be predicted ahead of time and preventative measures could be taken through a combination of conventional farming practices with contemporary technologies such as agri-drones to address the difficulties plaguing the agricultural sectors. Drones are actually unmanned aerial vehicles that are used for imaging, soil and crop surveillance, and a variety of other purposes in agricultural sectors. Drone technology is now becoming an emerging technology for large-scale applications in agriculture. Although the technology is still in its infancy in developing nations, numerous research and businesses are working to make it easily accessible to the farming community to boost the agricultural productivity

    Norsk rÄ kumelk, en kilde til zoonotiske patogener?

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    The worldwide emerging trend of eating “natural” foods, that has not been processed, also applies for beverages. According to Norwegian legislation, all milk must be pasteurized before commercial sale but drinking milk that has not been heat-treated, is gaining increasing popularity. Scientist are warning against this trend and highlights the risk of contracting disease from milkborne microorganisms. To examine potential risks associated with drinking unpasteurized milk in Norway, milk- and environmental samples were collected from dairy farms located in south-east of Norway. The samples were analyzed for the presence of specific zoonotic pathogens; Listeria monocytogenes, Campylobacter spp., and Shiga toxin-producing Escherichia coli (STEC). Cattle are known to be healthy carriers of these pathogens, and Campylobacter spp. and STEC have a low infectious dose, meaning that infection can be established by ingesting a low number of bacterial cells. L. monocytogenes causes one of the most severe foodborne zoonotic diseases, listeriosis, that has a high fatality rate. All three pathogens have caused milk borne disease outbreaks all over the world, also in Norway. During this work, we observed that the prevalence of the three examined bacteria were high in the environment at the examined farms. In addition, 7% of the milk filters were contaminated by STEC, 13% by L. monocytogenes and 4% by Campylobacter spp. Four of the STEC isolates detected were eaepositive, which is associated with the capability to cause severe human disease. One of the eae-positive STEC isolates were collected from a milk filter, which strongly indicate that Norwegian raw milk may contain potential pathogenic STEC. To further assess the possibilities of getting ill by STEC after consuming raw milk, we examined the growth of the four eae-positive STEC isolates in raw milk at different temperatures. All four isolates seemed to have ability to multiply in raw milk at 8°C, and one isolate had significant growth after 72 hours. Incubation at 6°C seemed to reduce the number of bacteria during the first 24 hours before cell death stopped. These findings highlight the importance of stable refrigerator temperatures, preferable < 4°C, for storage of raw milk. The L. monocytogenes isolates collected during this study show genetic similarities to isolates collected from urban and rural environmental locations, but different clones were predominant in agricultural environments compared to clinical and food environments. However, the results indicate that the same clone can persist in a farm over time, and that milk can be contaminated by L. monocytogenes clones present in farm environment. Despite testing small volumes (25 mL) of milk, we were able to isolate both STEC and Campylobacter spp. directly from raw milk. A proportion of 3% of the bulk tank milk and teat milk samples were contaminated by Campylobacter spp. and one STEC was isolated from bulk tank milk. L monocytogenes was not detected in bulk tank milk, nor in teat milk samples. The agricultural evolvement during the past decades have led to larger production units and new food safety challenges. Dairy cattle production in Norway is in a current transition from tie-stall housing with conventional pipeline milking systems, to modern loose housing systems with robotic milking. The occurrence of the three pathogens in this project were higher in samples collected from farms with loose housing compared to those with tiestall housing. Pasteurization of cow’s milk is a risk reducing procedure to protect consumers from microbial pathogens and in most EU countries, commercial distribution of unpasteurized milk is legally restricted. Together, the results presented in this thesis show that the animal housing may influence the level of pathogenic bacteria in the raw milk and that ingestion of Norwegian raw cow’s milk may expose consumers to pathogenic bacteria which can cause severe disease, especially in children, elderly and in persons with underlying diseases. The results also highlight the importance of storing raw milk at low temperatures between milking and consumption.Å spise mat som er mindre prosessert og mer «naturlig» er en pĂ„gĂ„ende trend i Norge og i andre deler av verden. Interessen for Ă„ drikke melk som ikke er varmebehandlet, sĂ„kalt rĂ„ melk, er ogsĂ„ Ăžkende. I Norge er det pĂ„budt Ă„ pasteurisere melk fĂžr kommersielt salg for Ă„ beskytte forbrukeren mot sykdomsfremkallende mikroorganismer. Fagfolk advarer mot Ă„ drikke rĂ„ melk, og pĂ„peker risikoen for Ă„ bli syk av patogene bakterier som kan finnes i melken. I denne avhandlingen undersĂžker vi den potensielle risikoen det medfĂžrer Ă„ drikke upasteurisert melk fra Norge. I tillegg til Ă„ samle inn tankmelk- og speneprĂžver fra melkegĂ„rder i sĂžrĂžst Norge, samlet vi ogsĂ„ miljĂžprĂžver fra de samme gĂ„rdene for Ă„ kartlegge forekomst og for Ă„ identifisere potensielle mattrygghetsrisikoer i melkeproduksjonen. Alle prĂžvene ble analysert for de zoonotiske sykdomsfremkallende bakteriene Listeria monocytogenes, Campylobacter spp., og Shiga toksin-produserende Escherichia coli (STEC). Kyr kan vĂŠre friske smittebĂŠrere av disse bakteriene, som dermed kan etablere et reservoar pĂ„ gĂ„rdene. Bakteriene kan overfĂžres fra gĂ„rdsmiljĂžet til melkekjeden og dermed utfordre mattryggheten. Disse bakteriene har forĂ„rsaket melkebĂ„rne sykdomsutbrudd over hele verden, ogsĂ„ i Norge. Campylobacter spp. og STEC har lav infeksiĂžs dose, som vil si at man kan bli syk selv om man bare inntar et lavt antall bakterieceller. L. monocytogenes kan gi sykdommen listeriose, en av de mest alvorlige matbĂ„rne zoonotiske sykdommene vi har i den vestlige verden. Resultater fra denne oppgaven viser en hĂžy forekomst av de tre patogenene i gĂ„rdsmiljĂžet. I tillegg var 7% av melkefiltrene vi testet positive for STEC, 13% positive for L. monocytogenes og 4% positive for Campylobacter spp.. Fire av STEC isolatene bar genet for Intimin, eae, som er ansett som en viktig virulensfaktor som Ăžker sjansen for alvorlig sykdom. Ett av de eae-positive isolatene ble funnet i et melkefilter, noe som indikerer at norsk rĂ„ melk kan inneholde patogene STEC. For Ă„ videre vurdere risikoen for Ă„ bli syk av STEC fra rĂ„ melk undersĂžkte vi hvordan de fire eae-positive isolatene vokste i rĂ„ melk lagret ved forskjellige temperaturer. For alle isolatene Ăžkte antall bakterier etter lagring ved 8°C, og for et isolat var veksten signifikant. Etter lagring ved 6°C ble antallet bakterier redusert de fĂžrste 24 timene, deretter stoppet reduksjonen i antall bakterier. Disse resultatene viser hvor viktig det er Ă„ ha stabil lav lagringstemperatur for rĂ„ melk, helst < 4°C. L. monocytogenes isolatene som ble samlet inn fra melkegĂ„rdene viste genetiske likheter med isolater samlet inn fra urbane og rurale miljĂžer rundt omkring i Norge. Derimot var kloner som dominerte i landbruksmiljĂžet forskjellige fra kliniske isolater og isolater fra matproduksjonslokaler. Videre sĂ„ man at en klone kan persistere pĂ„ en gĂ„rd over tid og at melk kan kontamineres av L. monocytogenes kloner som er til stede i gĂ„rdsmiljĂžet. Til tross for smĂ„ testvolum av tankmelken (25 mL) fant vi bĂ„de STEC og Campylobacter spp. i melkeprĂžvene. 3% av tankmelkprĂžvene og speneprĂžvene var positive for Campylobacter spp. og ett STEC isolat ble funnet i tankmelk. L. monocytogenes ble ikke funnet direkte i melkeprĂžvene. Landbruket i Norge er i stadig utvikling der besetningene blir stĂžrre, men fĂŠrre. Melkebesetningene er midt i en overgang der tradisjonell oppstalling med melking pĂ„ bĂ„s byttes ut med lĂžsdriftssystemer og melkeroboter. Forekomsten av de tre patogenene funnet i denne studien var hĂžyere i besetningene med lĂžsdrift sammenliknet med besetningene som hadde melkekyrne oppstallet pĂ„ bĂ„s. Pasteurisering er et viktig forebyggende tiltak for Ă„ beskytte konsumenter fra mikrobielle patogener, og i de fleste EU-land er kommersielt salg av rĂ„ melk juridisk begrenset. Denne studien viser at oppstallingstype kan pĂ„virke nivĂ„ene av patogene bakterier i gĂ„rdsmiljĂžet og i rĂ„ melk. Inntak av rĂ„ melk kan eksponere forbruker for patogene bakterier som kan gi alvorlig sykdom, spesielt hos barn, eldre og personer med underliggende sykdommer. Resultatene underbygger viktigheten av Ă„ pasteurisere melk for Ă„ sikre mattryggheten, og at det er avgjĂžrende Ă„ lagre rĂ„ melk ved kontinuerlig lave temperaturer for Ă„ forebygge vekst av zoonotiske patogener
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