11,450 research outputs found
Urinary biomarkers of biofortified beef in healthy women explored by untargeted metabolomics
Background: The prevalence of overweight and non-communicable chronic diseases is
rising all over the globe. The high consumption of energy dense foods on behalf of high
nutrient-dense food leads to lower intake of essential vitamins and minerals, such as
vitamins D, E, K, and selenium. These micronutrients are related with numerous human
vital functions and their deficiency is positively associated with higher risk of chronic
diseases and mortality. Bovine meat is an important source of several micronutrients, with
higher bioavailability compared to other plant-based foods. Meat consumption is expected
to increase worldwide, therefore the biofortification of bull’s feeds can be an innovative
strategy to increase population’s exposure to nutrients. Metabolomics techniques are
capable to explore if the supplementation will ultimately lead to a higher micronutrient’s
uptake in the body.
Objective: The aim of the present study was to explore the differences on urinary metabolic
fingerprint of women ingesting 300g of beef a day from bulls fed concentrate
supplemented with extra vitamin D, E, K, and selenium compared to the regular composite
feed.
Methodology: A 32 days double-blind randomized cross-over human intervention study
with two intervention periods, each for 6 days, was conducted in 35 healthy women. The
participants were instructed to eat 300g of grinded beef meat as raw weight per day, either
from bulls fed with regular control feed or meat supplemented with vitamin D, E, K and
selenium, combined with their habitual diet. Fasting urine samples were collected in the
morning before and after each intervention period and were analyzed by LC-MS
untargeted metabolomics. Multivariate and univariate analysis were applied do identify
discriminative features between the two interventions.
Results: A total of 7 and 6 metabolites for positive and negative mode, respectively, were
selected as discriminative of the two interventions. Among these, markers of overall meat
intake, as well as markers of animal feed, markers related with the participants diet and
inflammation-related markers were identified as upregulated or downregulated for the
supplemented intervention. No markers specifically related to the biofortification were
observed.
Conclusions: Based on our methodology, the ingestion of biofortified beef did not results
in a higher level of related metabolites when comparing the two interventions. Minor
changes indicate that consequences of biofortification were very small. Further research is
needed to understand if a higher increase of vitamin D, E, K, and selenium on animal´s feed
composite can lead to different outcomes
Pollution-induced community tolerance in freshwater biofilms – from molecular mechanisms to loss of community functions
Exposure to herbicides poses a threat to aquatic biofilms by affecting their community structure, physiology and function. These changes render biofilms to become more tolerant, but on the downside community tolerance has ecologic costs. A concept that addresses induced community tolerance to a pollutant (PICT) was introduced by Blanck and Wängberg (1988). The basic principle of the concept is that microbial communities undergo pollution-induced succession when exposed to a pollutant over a long period of time, which changes communities structurally and functionally and enhancing tolerance to the pollutant exposure. However, the mechanisms of tolerance and the ecologic consequences were hardly studied up to date. This thesis addresses the structural and functional changes in biofilm communities and applies modern molecular methods to unravel molecular tolerance mechanisms.
Two different freshwater biofilm communities were cultivated for a period of five weeks, with one of the communities being contaminated with 4 μg L-1 diuron. Subsequently, the communities were characterized for structural and functional differences, especially focusing on their crucial role of photosynthesis. The community structure of the autotrophs was assessed using HPLC-based pigment analysis and their functional alterations were investigated using Imaging-PAM fluorometry to study photosynthesis and community oxygen profiling to determine net primary production. Then, the molecular fingerprints of the communities were measured with meta-transcriptomics (RNA-Seq) and GC-based community metabolomics approaches and analyzed with respect to changes in their molecular functions. The communities were acute exposed to diuron for one hour in a dose-response design, to reveal a potential PICT and uncover related adaptation to diuron exposure. The combination of apical and molecular methods in a dose-response design enabled the linkage of functional effects of diuron exposure and underlying molecular mechanisms based on a sensitivity analysis.
Chronic exposure to diuron impaired freshwater biofilms in their biomass accrual. The contaminated communities particularly lost autotrophic biomass, reflected by the decrease in specific chlorophyll a content. This loss was associated with a change in the molecular fingerprint of the communities, which substantiates structural and physiological changes. The decline in autotrophic biomass could be due to a primary loss of sensitive autotrophic organisms caused by the selection of better adapted species in the course of chronic exposure. Related to this hypothesis, an increase in diuron tolerance has been detected in the contaminated communities and molecular mechanisms facilitating tolerance have been found. It was shown that genes of the photosystem, reductive-pentose phosphate cycle and arginine metabolism were differentially expressed among the communities and that an increased amount of potential antioxidant degradation products was found in the contaminated communities. This led to the hypothesis that contaminated communities may have adapted to oxidative stress, making them less sensitive to diuron exposure. Moreover, the photosynthetic light harvesting complex was altered and the photoprotective xanthophyll cycle was increased in the contaminated communities. Despite these adaptation strategies, the loss of autotrophic biomass has been shown to impair primary production. This impairment persisted even under repeated short-term exposure, so that the tolerance mechanisms cannot safeguard primary production as a key function in aquatic systems.:1. The effect of chemicals on organisms and their functions .............................. 1
1.1 Welcome to the anthropocene .......................................................................... 1
1.2 From cellular stress responses to ecosystem resilience ................................... 3
1.2.1 The individual pursuit for homeostasis ....................................................... 3
1.2.2 Stability from diversity ................................................................................. 5
1.3 Community ecotoxicology - a step forward in monitoring the effects of chemical
pollution? ................................................................................................................. 6
1.4 Functional ecotoxicological assessment of microbial communities ................... 9
1.5 Molecular tools – the key to a mechanistic understanding of stressor effects
from a functional perspective in microbial communities? ...................................... 12
2. Aims and Hypothesis ......................................................................................... 14
2.1 Research question .......................................................................................... 14
2.2 Hypothesis and outline .................................................................................... 15
2.3 Experimental approach & concept .................................................................. 16
2.3.1 Aquatic freshwater biofilms as model community ..................................... 16
2.3.2 Diuron as model herbicide ........................................................................ 17
2.3.3 Experimental design ................................................................................. 18
3. Structural and physiological changes in microbial communities after chronic
exposure - PICT and altered functional capacity ................................................. 21
3.1 Introduction ..................................................................................................... 21
3.2 Methods .......................................................................................................... 23
3.2.1 Biofilm cultivation ...................................................................................... 23
3.2.2 Dry weight and autotrophic index ............................................................. 23
3.2.4 Pigment analysis of periphyton ................................................................. 23
3.2.4.1 In-vivo pigment analysis for community characterization ....................... 24
3.2.4.2 In-vivo pigment analysis based on Imaging-PAM fluorometry ............... 24
3.2.4.3 In-vivo pigment fluorescence for tolerance detection ............................. 26
3.2.4.4 Ex-vivo pigment analysis by high-pressure liquid-chromatography ....... 27
3.2.5 Community oxygen metabolism measurements ....................................... 28
3.3 Results and discussion ................................................................................... 29
3.3.1 Comparison of the structural community parameters ............................... 29
3.3.2 Photosynthetic activity and primary production of the communities after
selection phase ................................................................................................. 33
3.3.3 Acquisition of photosynthetic tolerance .................................................... 34
3.3.4 Primary production at exposure conditions ............................................... 36
3.3.5 Tolerance detection in primary production ................................................ 37
3.4 Summary and Conclusion ........................................................................... 40
4. Community gene expression analysis by meta-transcriptomics ................... 41
4.1 Introduction to meta-transcriptomics ............................................................... 41
4.2. Methods ......................................................................................................... 43
4.2.1 Sampling and RNA extraction................................................................... 43
4.2.2 RNA sequencing analysis ......................................................................... 44
4.2.3 Data assembly and processing................................................................. 45
4.2.4 Prioritization of contigs and annotation ..................................................... 47
4.2.5 Sensitivity analysis of biological processes .............................................. 48
4.3 Results and discussion ................................................................................... 48
4.3.1 Characterization of the meta-transcriptomic fingerprints .......................... 49
4.3.2 Insights into community stress response mechanisms using trend analysis
(DRomic’s) ......................................................................................................... 51
4.3.3 Response pattern in the isoform PS genes .............................................. 63
4.5 Summary and conclusion ................................................................................ 65
5. Community metabolome analysis ..................................................................... 66
5.1 Introduction to community metabolomics ........................................................ 66
5.2 Methods .......................................................................................................... 68
5.2.1 Sampling, metabolite extraction and derivatisation................................... 68
5.2.2 GC-TOF-MS analysis ............................................................................... 69
5.2.3 Data processing and statistical analysis ................................................... 69
5.3 Results and discussion ................................................................................... 70
5.3.1 Characterization of the metabolic fingerprints .......................................... 70
5.3.2 Difference in the metabolic fingerprints .................................................... 71
5.3.3 Differential metabolic responses of the communities to short-term exposure
of diuron ............................................................................................................ 73
5.4 Summary and conclusion ................................................................................ 78
6. Synthesis ............................................................................................................. 79
6.1 Approaches and challenges for linking molecular data to functional
measurements ...................................................................................................... 79
6.2 Methods .......................................................................................................... 83
6.2.1 Summary on the data ............................................................................... 83
6.2.2 Aggregation of molecular data to index values (TELI and MELI) .............. 83
6.2.3 Functional annotation of contigs and metabolites using KEGG ................ 83
6.3 Results and discussion ................................................................................... 85
6.3.1 Results of aggregation techniques ........................................................... 85
6.3.2 Sensitivity analysis of the different molecular approaches and endpoints 86
6.3.3 Mechanistic view of the molecular stress responses based on KEGG
functions ............................................................................................................ 89
6.4 Consolidation of the results – holistic interpretation and discussion ............... 93
6.4.1 Adaptation to chronic diuron exposure - from molecular changes to
community effects.............................................................................................. 93
6.4.2 Assessment of the ecological costs of Pollution-induced community
tolerance based on primary production ............................................................. 94
6.5 Outlook ............................................................................................................ 9
Estudo da remodelagem reversa miocárdica através da análise proteómica do miocárdio e do líquido pericárdico
Valve replacement remains as the standard therapeutic option for aortic
stenosis patients, aiming at abolishing pressure overload and triggering
myocardial reverse remodeling. However, despite the instant hemodynamic
benefit, not all patients show complete regression of myocardial hypertrophy,
being at higher risk for adverse outcomes, such as heart failure. The current
comprehension of the biological mechanisms underlying an incomplete reverse
remodeling is far from complete. Furthermore, definitive prognostic tools and
ancillary therapies to improve the outcome of the patients undergoing valve
replacement are missing. To help abridge these gaps, a combined myocardial
(phospho)proteomics and pericardial fluid proteomics approach was followed,
taking advantage of human biopsies and pericardial fluid collected during
surgery and whose origin anticipated a wealth of molecular information
contained therein.
From over 1800 and 750 proteins identified, respectively, in the myocardium
and in the pericardial fluid of aortic stenosis patients, a total of 90 dysregulated
proteins were detected. Gene annotation and pathway enrichment analyses,
together with discriminant analysis, are compatible with a scenario of increased
pro-hypertrophic gene expression and protein synthesis, defective ubiquitinproteasome system activity, proclivity to cell death (potentially fed by
complement activity and other extrinsic factors, such as death receptor
activators), acute-phase response, immune system activation and fibrosis.
Specific validation of some targets through immunoblot techniques and
correlation with clinical data pointed to complement C3 β chain, Muscle Ring
Finger protein 1 (MuRF1) and the dual-specificity Tyr-phosphorylation
regulated kinase 1A (DYRK1A) as potential markers of an incomplete
response. In addition, kinase prediction from phosphoproteome data suggests
that the modulation of casein kinase 2, the family of IκB kinases, glycogen
synthase kinase 3 and DYRK1A may help improve the outcome of patients
undergoing valve replacement. Particularly, functional studies with DYRK1A+/-
cardiomyocytes show that this kinase may be an important target to treat
cardiac dysfunction, provided that mutant cells presented a different response
to stretch and reduced ability to develop force (active tension).
This study opens many avenues in post-aortic valve replacement reverse
remodeling research. In the future, gain-of-function and/or loss-of-function
studies with isolated cardiomyocytes or with animal models of aortic bandingdebanding will help disclose the efficacy of targeting the surrogate therapeutic
targets. Besides, clinical studies in larger cohorts will bring definitive proof of
complement C3, MuRF1 and DYRK1A prognostic value.A substituição da válvula aórtica continua a ser a opção terapêutica de
referência para doentes com estenose aórtica e visa a eliminação da
sobrecarga de pressão, desencadeando a remodelagem reversa miocárdica.
Contudo, apesar do benefício hemodinâmico imediato, nem todos os pacientes
apresentam regressão completa da hipertrofia do miocárdio, ficando com maior
risco de eventos adversos, como a insuficiência cardíaca. Atualmente, os
mecanismos biológicos subjacentes a uma remodelagem reversa incompleta
ainda não são claros. Além disso, não dispomos de ferramentas de
prognóstico definitivos nem de terapias auxiliares para melhorar a condição
dos pacientes indicados para substituição da válvula. Para ajudar a resolver
estas lacunas, uma abordagem combinada de (fosfo)proteómica e proteómica
para a caracterização, respetivamente, do miocárdio e do líquido pericárdico
foi seguida, tomando partido de biópsias e líquidos pericárdicos recolhidos em
ambiente cirúrgico.
Das mais de 1800 e 750 proteínas identificadas, respetivamente, no miocárdio
e no líquido pericárdico dos pacientes com estenose aórtica, um total de 90
proteínas desreguladas foram detetadas. As análises de anotação de genes,
de enriquecimento de vias celulares e discriminativa corroboram um cenário de
aumento da expressão de genes pro-hipertróficos e de síntese proteica, um
sistema ubiquitina-proteassoma ineficiente, uma tendência para morte celular
(potencialmente acelerada pela atividade do complemento e por outros fatores
extrínsecos que ativam death receptors), com ativação da resposta de fase
aguda e do sistema imune, assim como da fibrose.
A validação de alguns alvos específicos através de immunoblot e correlação
com dados clínicos apontou para a cadeia β do complemento C3, a Muscle
Ring Finger protein 1 (MuRF1) e a dual-specificity Tyr-phosphoylation
regulated kinase 1A (DYRK1A) como potenciais marcadores de uma resposta
incompleta. Por outro lado, a predição de cinases a partir do fosfoproteoma,
sugere que a modulação da caseína cinase 2, a família de cinases do IκB, a
glicogénio sintase cinase 3 e da DYRK1A pode ajudar a melhorar a condição
dos pacientes indicados para intervenção. Em particular, a avaliação funcional
de cardiomiócitos DYRK1A+/- mostraram que esta cinase pode ser um alvo
importante para tratar a disfunção cardíaca, uma vez que os miócitos mutantes
responderam de forma diferente ao estiramento e mostraram uma menor
capacidade para desenvolver força (tensão ativa).
Este estudo levanta várias hipóteses na investigação da remodelagem reversa.
No futuro, estudos de ganho e/ou perda de função realizados em
cardiomiócitos isolados ou em modelos animais de banding-debanding da
aorta ajudarão a testar a eficácia de modular os potenciais alvos terapêuticos
encontrados. Além disso, estudos clínicos em coortes de maior dimensão
trarão conclusões definitivas quanto ao valor de prognóstico do complemento
C3, MuRF1 e DYRK1A.Programa Doutoral em Biomedicin
Effects of replacing dietary fish oil and fish meal with microbial oil and algal biomass on lipid class, total fatty acid and phospholipid fatty acid composition of Atlantic salmon liver and muscle tissues
With the continuous growth of aquaculture comes a growing demand for an alternative lipid source for fish oil (FO) and fish meal (FM) in aquafeeds. Certain microorganisms provide a potential sustainable replacement for FO and FM due to their content of omega-3 (ω3) long-chain polyunsaturated fatty acids, which are essential for the growth and health of fish. Two feeding trials were conducted to determine the effects of replacing FO and FM with oil and biomass from two different microorganism species. The first feeding trial comprised of replacing FO with a microbial oil (MO) derived from a novel strain, Schizochytrium sp. (strain T18), in diets for Atlantic salmon. Four experimental diets were developed: a fish oil control diet (FO), a blend of fish oil/canola oil control diet (FO/CO), a fish oil replacement with low proportions of microbial oil diet (LMO), and a fish oil replacement with high proportions of microbial oil diet (HMO). After 16 weeks of feeding, there were no significant effects on growth parameters across the dietary treatments. Fatty acid profiles reflected the diets with DHA being present in high proportions in the tissues, especially in the cellular membrane. The purpose of the second feeding trial was to reduce FO and replacing FM with algal biomass (AB) derived from Pavlova sp. strain CCMP459 (Pav459) in diets for Atlantic salmon. Three experimental diets were developed: a fish meal control diet (FM), a blend of a fish meal/algal biomass Pav459 diet (FM/AB), and a complete FM replacement with algal biomass Pav459 diet (AB). After 12 weeks of feeding, again, there was no significant effect on growth paraments, and the fatty acid profiles also reflected those of the diets. The DHA was present in high proportions in the tissues for all dietary treatments, especially the cellular membrane. The stable isotope data suggested a direct integration of EPA and DHA and not biosynthesis from its precursor ALA
Can analytics software measure end user computing electricity consumption?
The purpose of this research is to answer the question, ‘can analytics software measure end user computing electricity consumption?’ The rationale being that the success of traditional methodologies, such as watt metres, is limited by newly evolved barriers such as mobility and scale (Greenblatt et al., in Field data collection of miscellaneous electrical loads in Northern California: initial results. Ernest Orlando Lawrence Berkeley National Laboratory research paper, pp 4–5, 2013). Such limitations significantly reduce the availability of end user computing use phase energy consumption field data (Karpagam and Yung, in J Clean Prod 156:828, 2017). This causes computer manufacturers to instead rely upon no-user present energy efficiency benchmarks (Energy Star, in Product finder, product, certified computers, results. Washington, D.C.: United States Department of Energy. https://www.energystar.gov/productfinder/product/certified-computers/results, 2021) to act as baseline data for product carbon footprint reports. As the benchmark approach is previously tested to cause scope 2 greenhouse gas emissions quantification to be inaccurate by − 48% to + 107% (Sutton-Parker, in Determining end user computing device Scope 2 GHG emissions with accurate use phase energy consumption measurement, 1877-0509. Amsterdam: Science Direct, Elsevier B.V., 2020), testing a new methodology that includes the impact of human–computer interaction is arguably of value. As such, the proposed method is tested using a distributed node based analytics software to capture both computer asset and human use profile data sets from one hundred and eleven computer users operating in a subject organisation for 30-days. The simple rationale is that the node, unlike a watt metre, is not restricted by location, can be deployed and monitored globally from a centralised location and can move with the computer to ensure constant measurement. The resulting data sets are used to populate a current use phase electricity consumption calculation data flow (Kawamoto et al., in Energy 27:255, 2001; Roth et al., in Energy consumption by office and telecommunications equipment in commercial buildings: energy consumption baseline, 2002) in order to examine for omissions. Additionally, to test for data accuracy, one computer user acts as a control subject, measuring electricity consumption with both a watt-metre and the analytics software. The rationale being that the watt-metre data is extensively proven to be accurate (Energy Star, in Energy star computers final version 8.0 Specification, Washington D.C., United States Department of Energy. https://www.energystar.gov/products/spec/computers_version_8_0_pd, 2020) and will therefore expose errors produced by the software in relation to power draw, on-time and resulting kilo-watt hours (kWh) values. Further to the data capture period, the findings are mixed. Positively, the new method overcomes the barriers of numerous, assorted devices (scale) operating in ever changing locations (mobility). This is achieved by the node reporting in real-time make and model asset data together with device specific electricity consumption and location data via internet technologies. Negatively, the control subject identifies that the electricity consumption values produced by the software are inaccurate by a relatively constant 48%. Furthermore, data omissions are experienced including the exclusion of computer displays caused by the node requiring an operating system to collect data. This latter point would exclude the energy consumption measurement and therefore concomitant greenhouse gas emissions of any displays connected to desktop or mobile computers. Consequently, whilst the research question is answered, the identification of the software exaggerating use phase energy consumption by 48% and excluding peripheral devices, determines the analytics methodology to be in need of further development. The rationale being that use phase consumption quantification is key to lifecycle assessment and greenhouse gas accounting protocol and both require high levels of accuracy (WBCSD and WRI, in The greenhouse gas protocol. A corporate accounting and reporting standard, Geneva, Switzerland and New York, USA. https://ghgprotocol.org/corporate-standard, 2004). It is therefore recommended that further research be undertaken to specifically address omissions and to reduce the over reporting aspect identified as caused by algorithms in the software used to calculate hardware power draw
Acoustic Array Biochip Combined with Allele-Specific PCR for Multiple Cancer Mutation Analysis in Tissue and Liquid Biopsy
[EN] Regular screening of point mutations is of importance to cancer management and treatment selection. Although techniques like next-generation sequencing and digital polymerase chain reaction (PCR) are available, these are lacking in speed, simplicity, and cost-effectiveness. The development of alternative methods that can detect the extremely low concentrations of the target mutation in a fast and cost-effective way presents an analytical and technological challenge. Here, an approach is presented where for the first time an allele-specific PCR (AS-PCR) is combined with a newly developed high fundamental frequency quartz crystal microbalance array as biosensor for the amplification and detection, respectively, of cancer point mutations. Increased sensitivity, compared to fluorescence detection of the AS-PCR amplicons, is achieved through energy dissipation measurement of acoustically ¿lossy¿ liposomes binding to surface-anchored dsDNA targets. The method, applied to the screening of BRAF V600E and KRAS G12D mutations in spiked-in samples, was shown to be able to detect 1 mutant copy of genomic DNA in an excess of 104 wild-type molecules, that is, with a mutant allele frequency (MAF) of 0.01%. Moreover, validation of tissue and plasma samples obtained from melanoma, colorectal, and lung cancer patients showed excellent agreement with Sanger sequencing and ddPCR; remarkably, the efficiency of this AS-PCR/acoustic methodology to detect mutations in real samples was demonstrated to be below 1% MAF. The combined high sensitivity and technology-readiness level of the methodology, together with the ability for multiple sample analysis (24 array biochip), cost-effectiveness, and compatibility with routine workflow, make this approach a promising tool for implementation in clinical oncology labs for tissue and liquid biopsy.This work was supported by the European Union's Horizon H2020-FETOPEN-1-2016-2017 under grant agreement no. 737212 (CATCH-U-DNA).Naoumi, N.; Michaelidou, K.; Papadakis, G.; Simaiaki, AE.; Fernández Díaz, R.; Calero-Alcarria, MDS.; Arnau Vives, A.... (2022). Acoustic Array Biochip Combined with Allele-Specific PCR for Multiple Cancer Mutation Analysis in Tissue and Liquid Biopsy. ACS Sensors. 7(2):495-503. https://doi.org/10.1021/acssensors.1c02245S4955037
Examining the Impact of Personal Social Media Use at Work on Workplace Outcomes
A noticable shift is underway in today’s multi-generational workforce. As younger employees propel digital workforce transformation and embrace technology adoption in the workplace, organisations need to show they are forward-thinking in their digital transformation strategies, and the emergent integration of social media in organisations is reshaping internal communication strategies, in a bid to improve corporate reputations and foster employee engagement. However, the impact of personal social media use on psychological and behavioural workplace outcomes is still debatebale with contrasting results in the literature identifying both positive and negative effects on workplace outcomes among organisational employees.
This study seeks to examine this debate through the lens of social capital theory and study personal social media use at work using distinct variables of social use, cognitive use, and hedonic use. A quantitative analysis of data from 419 organisational employees in Jordan using SEM-PLS reveals that personal social media use at work is a double-edged sword as its impact differs by usage types. First, the social use of personal social media at work reduces job burnout, turnover intention, presenteeism, and absenteeism; it also increases job involvement and organisational citizen behaviour. Second, the cognitive use of personal social media at work increases job involvement, organisational citizen behaviour, employee adaptability, and decreases presenteeism and absenteeism; it also increases job burnout and turnover intention. Finally, the hedonic use of personal social media at work carries only negative effects by increasing job burnout and turnover intention.
This study contributes to managerial understanding by showing the impact of different types of personal social media usage and recommends that organisations not limit employee access to personal social media within work time, but rather focus on raising awareness of the negative effects of excessive usage on employee well-being and encourage low to moderate use of personal social media at work and other personal and work-related online interaction associated with positive workplace outcomes. It also clarifies the need for further research in regions such as the Middle East with distinct cultural and socio-economic contexts
Transporte sedimentar de misturas arenosas em ambientes costeiros
Sediment dynamics is a complex subject, playing an important role in coastal areas. The interaction between the wave action and sediment particles is determinant to understand sediment transport. The knowledge of sediment transport in sand mixtures is relevant as the coastal zone usually presents large heterogeneities of sediment particles sizes in the horizontal and vertical directions, which denote the existence of selective transport process.
The goal of the present study was to understand selective sand transport mechanisms associated with wave-dominated conditions. To achieve the proposed objective, the work was supported by several approaches to give insights into the processes associated with heterometric sediment transport. The first approach consisted in a review of the literature to understand what is known and the lack of knowledge in the subject. The second approach consisted in performing a set of experiments with fluorescent sand tracers in natural conditions, at the field, and in a controlled environment, at the laboratory. The experiment conducted at Patos beach, Spain, aimed to observe the behavior of the native sand in the natural environment. The one performed at a large wave flume (Großer Wellenkanal, GWK) in Hannover, considered distinct sediment mixtures under two wave conditions. In both, measurements of the total and fractional transport were made. Finally, a quasi-steady and a semi-unsteady model were considered to calculate the net sediment transport of a large data set, for uniform and graded sand, allowing to identify limitations of the models and to propose new methodologies to obtain more adequate results.
The experimental results obtained in the field allowed to observe the tracer transport towards the beach, in the wave direction, and to characterize the transport of the different fractions of the tracer in terms of the hydrodynamic processes. The laboratory experiment allowed to verify the occurrence of interaction between the sand fractions, with the finer (coarser) sediment decreasing (increasing) their transport, as the percentage of coarse sand in the bed mixture increases.
The validation of the models was conducted and their performance was improved with the introduction of parameters related to surface wave streaming effects and bedforms.A dinâmica sedimentar é um tema complexo, desempenhando um papel importante nas zonas costeiras. A interação entre a ação das ondas e as partículas de sedimento é determinante para compreender o transporte sedimentar. O conhecimento do transporte de sedimentos heterométricos é relevante uma vez que a zona costeira apresenta geralmente grandes heterogeneidades na dimensão das partículas sedimentares nas direções horizontal e vertical, o que denota a existência de processos seletivos de transporte.
O presente estudo teve como objetivo compreender os mecanismos de transporte seletivo de areia associados a condições hidrodinâmicas dominadas pelas ondas e considerou diferentes abordagens para evidenciar os processos que intervêm no transporte de sedimentos heterométricos. A primeira abordagem consistiu numa revisão da literatura para compreender o conhecimento atual e as lacunas existentes. A segunda abordagem consistiu na realização de um conjunto de experiências com traçadores de areia fluorescente em condições naturais, no campo, e em ambiente controlado, no laboratório. A experiência realizada na praia de Patos, Espanha, visou observar o comportamento da areia nativa em ambiente natural. A experiência realizada no grande canal de ondas (Großer Wellenkanal, GWK) em Hannover, considerou misturas de sedimentos com granulometrias distintas sob duas condições de ondas. Em ambas as experiências, foram feitas medições do transporte total e fracionado. Finalmente, um modelo quase-estacionário e um modelo semi-não estacionário foram considerados para calcular as taxas de transporte sedimentar de um grande conjunto de dados experimentais, para areia uniforme e heterométrica, permitindo identificar limitações dos modelos e propor novas metodologias para obter resultados mais adequados.
Os resultados experimentais obtidos no campo permitiram observar o transporte do traçador em direcção à praia, na direcção das ondas, e caracterizar o transporte das diferentes frações do traçador em termos dos processos hidrodinâmicos. A experiência laboratorial permitiu verificar a ocorrência de processos de interação no transporte das diferentes frações de areia, com a fração mais fina do sedimento (mais grosseira) a diminuir (aumentar) o seu transporte, à medida que a percentagem de areia grosseira na mistura do leito de fundo aumenta.
A validação dos modelos foi realizada e o seu desempenho foi melhorado com a introdução de parâmetros relacionados com os efeitos de streaming e formas de fundo.Programa Doutoral em Ciência, Tecnologia e Gestão do Ma
Irish research response to dairy quality in an era of change
peer-reviewedThe Irish dairy sector is recognised for its very significant contribution to the national economic status; it is now worth ∼€5 billion annually and represents the largest food and drink export category, which, in turn, represents one of the four largest manufacturing industries in the country. Given anticipated further growth in global demand for dairy products and the positive attributes and capabilities that Ireland has to meet that demand, in terms of pasture-based production and cost competitiveness, it is incumbent for the sector to attain the highest quality milk and dairy products. The combined collaborative approach between research and industry has ensured significant progress and enabled Ireland to remain at the forefront globally in terms of production of quality milk and dairy products. This paper highlights some specific scientific platforms and technologies currently shaping the industry in this regard and discusses current research activity as well as anticipating key requirements for future progress. While research, and farm and processing plant management have accomplished very significant advances in milk and dairy product quality, some overarching emerging challenges include product substitution and sustainability. Some key pillars for the future have been identified on which a strong, efficient dairy sector can be maintained and progressed. Specifically, the use of evidence-based information and real-time measures in prediction and decision-making will be a crucial pillar for the dairy sector of the future. This can promote an approach of proactive maintenance and optimisation of production through improved predictability and control of manufacturing processes
'Inventions and adventures': the work of the Stevenson engineering firm in Scotland, c. 1830 - c. 1890
This thesis examines the work of the nineteenth-century Stevenson civil engineering firm to argue
that civil engineering should be approached geographically both because it takes place in and is
shaped by particular spaces, but also because the result of such work reshapes space and the
relationship between places. Geographers have extensively analysed the ways in which humans
have worked to alter environments, but relatively little attention has been paid to engineering as a
socially and geographically transformative process, to the technical questions and to the engineering
professionals whose work brought about such change. This thesis analyses engineers as social and
technical agents of environmental change, rather than viewing their role as the simple
implementation of directives developed elsewhere and by others. It combines insights from the
history and historical geography of science, environmental history and the history of technology to
make a case for the relevance of an historical geography of engineering.
The thesis explores these issues through the work of the Stevenson family. The Stevensons
were an Edinburgh-based and internationally-renowned firm of engineers who specialised in the
construction of coastal infrastructure. The start and end dates of the thesis indicate, broadly, the
careers of David and Thomas Stevenson, who jointly managed the family firm under the name D. &
T. Stevenson between 1850 and 1886. The empirical basis for this thesis draws upon the detailed
analysis of the firm’s archival records: technical publications, project reports, diaries,
correspondence, maps, plans and diagrams.
The work of the Stevensons—their engineering epistemologies, practices, and professional
identities— are examined through four diverse projects undertaken by the firm in the nineteenth
century. These projects are: the training of new engineers; surveying and designing improvement
works for the rivers Tay and Clyde; the implementation of a coastal sound-based fog signal network;
and the failed attempt to expand Wick harbour through the construction of a breakwater. These
projects highlight the range of activities undertaken by nineteenth-century engineers and illustrate
the ‘making’ of engineers and the work they did by highlighting training and learning, surveying,
maintenance, testing, evaluation, repair and the explanation of failure. With reference to these
projects and by drawing upon relevant contextual material, the thesis examines the
conceptualisation of geographical space and natural forces in engineering, the relationship between
science and engineering, the nature of expertise and notions of engineering judgement, and the role
of family, legacy and reputation in securing professional credibility and status.
This approach challenges older historiographical traditions which portrayed engineers as
individual geniuses. The thesis instead understands engineering to be a combination of specialist
knowledge and tacit skill and situates engineers within their social and institutional networks of
power and authority. In pointing out that some engineering works failed, the thesis challenges the
tendency in histories of engineering works to focus on success. It makes the case for an historical
geography of engineering as a way of understanding engineering as an activity, a status and as
processes which changed human-environment relations
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