274 research outputs found

    Submesoscale Rossby waves on the Antarctic circumpolar current.

    Get PDF
    The eastward-flowing Antarctic circumpolar current (ACC) plays a central role in the global ocean overturning circulation and facilitates the exchange of water between the ocean surface and interior. Submesoscale eddies and fronts with scales between 1 and 10 km are regularly observed in the upper ocean and are associated with strong vertical circulations and enhanced stratification. Despite their importance in other locations, comparatively little is known about submesoscales in the Southern Ocean. We present results from new observations, models, and theories showing that submesoscales are qualitatively changed by the strong jet associated with the ACC in the Scotia Sea, east of Drake Passage. Growing submesoscale disturbances develop along a dense filament and are transformed into submesoscale Rossby waves, which propagate upstream relative to the eastward jet. Unlike their counterparts in slower currents, the submesoscale Rossby waves do not destroy the underlying frontal structure. The development of submesoscale instabilities leads to strong net subduction of water associated with a dense outcropping filament, and later, the submesoscale Rossby waves are associated with intense vertical circulations

    Storm-triggered, increased supply of sediment-derived phosphorus to the epilimnion in a small freshwater lake

    Get PDF
    This study investigated internal loading of sediment-derived phosphorus (P) in a small, meso-eutrophic lake (surface area 0.2 km2, catchment area 2.7 km2, mean depth 6 m, maximum depth 14 m) on the Atlantic seaboard of western Europe. High resolution data collected over 2.5 years (1 Mar 2011 to 30 Sep 2013) revealed inconsistent patterns in (1) the timing and magnitude of lake turnover and (2) the relative importance of the transfer of hypolimnetic sediment-derived P to the epilimnion when compared with external catchment loading. Lake turnover events during spring and summer had the effect of increasing the internal loading of epilimnetic P during the main growing season, thus adding to eutrophication pressure and contributing to algal blooms in the lake. Abrupt pre-fall (autumnal) turnover events and associated increases in eutrophication pressure such as those reported here may become more frequent occurrences in western Europe because of warming-induced increases in Atlantic summer storm frequency and magnitude, and they could counter the apparent effectiveness of measures aimed at reducing eutrophication impacts through limiting external loadings of nutrients from the catchment

    Storm-triggered, increased supply of sediment-derived phosphorus to the epilimnion in a small freshwater lake

    Get PDF
    This study investigated internal loading of sediment-derived phosphorus (P) in a small, meso-eutrophic lake (surface area 0.2 km2, catchment area 2.7 km2, mean depth 6 m, maximum depth 14 m) on the Atlantic seaboard of western Europe. High resolution data collected over 2.5 years (1 Mar 2011 to 30 Sep 2013) revealed inconsistent patterns in (1) the timing and magnitude of lake turnover and (2) the relative importance of the transfer of hypolimnetic sediment-derived P to the epilimnion when compared with external catchment loading. Lake turnover events during spring and summer had the effect of increasing the internal loading of epilimnetic P during the main growing season, thus adding to eutrophication pressure and contributing to algal blooms in the lake. Abrupt pre-fall (autumnal) turnover events and associated increases in eutrophication pressure such as those reported here may become more frequent occurrences in western Europe because of warming-induced increases in Atlantic summer storm frequency and magnitude, and they could counter the apparent effectiveness of measures aimed at reducing eutrophication impacts through limiting external loadings of nutrients from the catchment

    Melanoma-restricted genes

    Get PDF
    Human metastatic cutaneous melanoma has gained a well deserved reputation for its immune responsiveness. The reason(s) remain(s) unknown. We attempted previously to characterize several variables that may affect the relationship between tumor and host immune cells but, taken one at the time, none yielded a convincing explanation. With explorative purposes, high-throughput technology was applied here to portray transcriptional characteristics unique to metastatic cutaneous melanoma that may or may not be relevant to its immunogenic potential. Several functional signatures could be identified descriptive of immune or other biological functions. In addition, the transcriptional profile of metastatic melanoma was compared with that of primary renal cell cancers (RCC) identifying several genes co-coordinately expressed by the two tumor types. Since RCC is another immune responsive tumor, commonalities between RCC and melanoma may help untangle the enigma of their potential immune responsiveness. This purely descriptive study provides, therefore, a map for the investigation of metastatic melanoma in future clinical trials and at the same time may invite consideration of novel therapeutic targets

    Selection and validation of endogenous reference genes using a high throughput approach

    Get PDF
    BACKGROUND: Endogenous reference genes are commonly used to normalize expression levels of other genes with the assumption that the expression of the former is constant in different tissues and in different physiopathological conditions. Whether this assumption is correct it is, however, still matter of debate. In this study, we searched for stably expressed genes in 384 cDNA array hybridization experiments encompassing different tissues and cell lines. RESULTS: Several genes were identified whose expression was highly stable across all samples studied. The usefulness of 8 genes among them was tested by normalizing the relative gene expression against test genes whose expression pattern was known. The range of accuracy of individual endogenous reference genes was wide whereas consistent information could be obtained when information pooled from different endogenous reference genes was used. CONCLUSIONS: This study suggests that even when the most stably expressed genes in array experiments are used as endogenous reference, significant variation in test gene expression estimates may occur and the best normalization is achieved when data from several endogenous reference genes are pooled together to minimize minimal but significant variation among samples. We are presently optimizing strategies for the preparation of endogenous reference gene mixtures that could yield information comparable to that of data pooled from individual endogenous reference gene normalizations

    Improved Imputation of Common and Uncommon Single Nucleotide Polymorphisms (SNPs) with a New Reference Set

    Get PDF
    Statistical imputation of genotype data is an important technique for analysis of genome-wide association studies (GWAS). We have built a reference dataset to improve imputation accuracy for studies of individuals of primarily European descent using genotype data from the Hap1, Omni1, and Omni2.5 human SNP arrays (Illumina). Our dataset contains 2.5-3.1 million variants for 930 European, 157 Asian, and 162 African/African-American individuals. Imputation accuracy of European data from Hap660 or OmniExpress array content, measured by the proportion of variants imputed with R^2^>0.8, improved by 34%, 23% and 12% for variants with MAF of 3%, 5% and 10%, respectively, compared to imputation using publicly available data from 1,000 Genomes and International HapMap projects. The improved accuracy with the use of the new dataset could increase the power for GWAS by as much as 8% relative to genotyping all variants. This reference dataset is available to the scientific community through the NCBI dbGaP portal. Future versions will include additional genotype data as well as non-European populations

    Uncomfortable truths - teamworking under lean in the UK

    Get PDF
    A recent contribution in this journal – Procter, S. and Radnor, Z. (2014) ‘Teamworking under Lean in UK public services: lean teams and team targets in Her Majesty’s Revenue and Customs (HMRC)’ International Journal of Human Resource Management, 25:21, 2978–2995 – provides an account of teamworking in the UK Civil Service, specifically Her Majesty’s Revenue and Customs (HMRC), focused on the relationship between recently implemented lean work organisation and teams and teamworking. Procter and Radnor claim in this work that it delivers a ‘more nuanced’ analysis of lean in this government department and, it follows, of the lean phenomenon more generally. Our riposte critiques their article on several grounds. It suffers from problems of logic and construction, conceptual confusion and definitional imprecision. Methodological difficulties and inconsistent evidence contribute additionally to analytical weakness. Included in our response are empirical findings on teamworking at HMRC that challenge Procter and Radnor’s evidential basis and further reveal the shortcomings of their interpretation

    The transformative potential of international service-learning at a university with a Christian foundation in the UK

    Get PDF
    This article draws upon the findings of a study at Liverpool Hope University (LHU) into the transformative nature of International Service-Learning (ISL) experiences for student participants. This research is concerned with the implications of these findings for professional practice, in particular how ISL is constructed in Higher Education policy and practice. Recognising the problematic nature of this endeavor, this article responds to a call for discussion around pedagogical approaches underpinning counter-cultural and critical service programmes aligned with the radical principles of the Catholic social teaching. This study is grounded in a holistic conceptualisation of transformative learning that demands looking beyond an epistemological process that involves shifts in worldview and habits of mind to an ontological process that accounts for changes to our being in the world. It investigated how LHU students describe their ongoing experience of ISL and explored the conditions for learning and the associated transformative processes and outcomes in this context. Data analysis involved phenomenological description, constant comparative thematic analysis followed by a critical, hermeneutical analysis. This article will explicate the themes of moral and spiritual learning that emerged as part of a broader framework. In particular, it was found that the development of authentic relationships between travelling companions, accompanying tutors and partners overseas is central to learning that is reciprocated and provides a model of the transformative process in this context. This article concludes that this presents a pedagogical approach grounded in social justice that enables ISL to reach its transformative potential

    Transforming U.S. agriculture with crushed rock for CO2_2 sequestration and increased production

    Full text link
    Enhanced weathering (EW) is a promising modification to current agricultural practices that uses crushed silicate rocks to drive carbon dioxide removal (CDR). If widely adopted on farmlands, it could help achieve net-zero or negative emissions by 2050. We report detailed state-level analysis indicating EW deployed on agricultural land could sequester 0.23-0.38 Gt CO2_2 yr1^{-1} and meet 36-60 % of U.S. technological CDR goals. Average CDR costs vary between state, being highest in the first decades before declining to a range of $\sim\$100-150 tCO21_2{}^{-1} by 2050, including for three states (Iowa, Illinois, and Indiana) that contribute most to total national CDR. We identify multiple electoral swing states as being essential for scaling EW that are also key beneficiaries of the practice, indicating the need for strong bipartisan support of this technology. Assessment the geochemical capacity of rivers and oceans to carry dissolved EW products from soil drainage suggests EW provides secure long-term CO2_2 removal on intergenerational time scales. We additionally forecast mitigation of ground-level ozone increases expected with future climate change, as an indirect benefit of EW, and consequent avoidance of yield reductions. Our assessment supports EW as a practical innovation for leveraging agriculture to enable positive action on climate change with adherence to federal environmental justice priorities. However, implementing a stage-gating framework as upscaling proceeds to safeguard against environmental and biodiversity concerns will be essential
    corecore