Synchronized multiple drop impacts into a deep pool

Drop impacts (onto dry or wet surfaces or into deep pools) are important in a wide range of applications, and, consequently, many studies, both experimental and numerical, are available in the literature. However, such works are focused either on statistical analyses of drop populations or on single drops. The literature is heavily lacking in information about the mutual interactions between a few drops during the impact. This work describes a computational fluid dynamics (CFD) study on the impact of two, three, and four synchronized drops into a deep pool. The two-phase finite-volume solver interFoam of the open source CFD package OpenFOAM® was used. After validation with respect to high speed videos, to confirm the performance of the solver in this field, impact conditions and aspects that would have been difficult to obtain and to study in experiments were investigated: namely, the energy conversion during the crater evolution, the effect of varying drop interspace and surface tension, and multiple drop impacts. The results show the very significant effect of these aspects. This implies that an extension of the results of single-drop, distilled-water laboratory experiments to real applications may not be reliable

Land use change and the impact on greenhouse gas exchange in north Australian savanna soils

Savanna ecosystems are subjected to accelerating land use change as human demand for food and forest products increases. Land use change has been shown to both increase and decrease greenhouse gas fluxes from savannas and considerable uncertainty exists about the non-CO₂ fluxes from the soil. We measured methane (CH₄), nitrous oxide (N₂O) and carbon dioxide (CO₂) over a complete wet-dry seasonal cycle at three replicate sites of each of three land uses: savanna, young pasture and old pasture (converted from savanna 5–7 and 25–30 yr ago, respectively) in the Douglas Daly region of Northern Australia. The effect of break of season rains at the end of the dry season was investigated with two irrigation experiments. Land use change from savanna to pasture increased net greenhouse gas fluxes from the soil. Pasture sites were a weaker sink for CH₄ than savanna sites and, under wet conditions, old pastures turned from being sinks to a significant source of CH₄. Nitrous oxide emissions were generally very low, in the range of 0 to 5 μg N₂O-N m⁻² h⁻¹, and under dry conditions soil uptake of N₂O was apparent. Break of season rains produced a small, short lived pulse of N₂O up to 20 μg N₂O-N m⁻² h⁻¹, most evident in pasture soil. Annual cumulative soil CO₂ fluxes increased after clearing, with savanna (14.6 t CO₂-C ha⁻¹ yr⁻¹) having the lowest fluxes compared to old pasture (18.5 t CO₂-C ha⁻¹ yr⁻¹) and young pasture (20.0 t CO₂-C ha⁻¹ yr⁻¹). Clearing savanna increased soil-based greenhouse gas emissions from 53 to ∼ 70 t CO₂-equivalents, a 30% increase dominated by an increase in soil CO₂ emissions and shift from soil CH₄ sink to source. Seasonal variation was clearly driven by soil water content, supporting the emerging view that soil water content is a more important driver of soil gas fluxes than soil temperature in tropical ecosystems where temperature varies little among seasons

Characterization of highly hydrophobic textiles by means of X-ray microtomography, wettability analysis and drop impact

Highly hydrophobic surfaces have been intensively investigated in the last years because their properties may lead to very promising technological spillovers encompassing both everyday use and high-tech fields. Focusing on textiles, hydrophobic fabrics are of major interest for applications ranging from clothes to architecture to environment protection and energy conversion. Gas diffusion media - made by a gas diffusion layer (GDL) and a microporous layer (MPL) - for fuel cells are a good benchmark to develop techniques aimed at characterizing the wetting performances of engineered textiles. An experimental investigation was carried out about carbon-based, PTFE-treated GDLs with and without MPLs. Two samples (woven and woven-non-woven) were analysed before and after coating with a MPL. Their three-dimensional structure was reconstructed and analysed by computer-aided X-ray microtomography (CT). Static and dynamic wettability analyses were then carried out using a modified axisymmetric drop shape analysis technique. All the surfaces exhibited very high hydrophobicity, three of them near to a super-hydrophobic behavior. Water drop impacts were performed, evidencing different bouncing, sticking and fragmentation outcomes for which critical values of the Weber number were identified. Finally, a CT scan of a drop on a GDL was performed, confirming the Cassie-Baxter wetting state on such surface

Genomic profiling reveals spatial intra-tumor heterogeneity in follicular lymphoma

We are indebted to the patients for donating tumor specimens as part of this study. The authors thank the Centre de Ressources Biologiques (CRB)-Santé of Rennes (BB-0033-00056) for patient samples, Queen Mary University of London Genome Centre for Illumina Miseq sequencing, and the support by the National Institute for Health Research (NIHR) Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London for Illumina Hiseq sequencing. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health. This work was supported by grants from the Kay Kendall Leukaemia Fund (KKL 757 awarded to J.O.), Cancer Research UK (22742 awarded to J.O., 15968 awarded to J.F., Clinical Research Fellowship awarded to S.A.), Bloodwise through funding of the Precision Medicine for Aggressive Lymphoma (PMAL) consortium, Centre for Genomic Health, Queen Mary University of London, Carte d’Identité des Tumeurs (CIT), Ligue National contre le Cancer, Pôle de biologie hospital universitaire de Rennes, CRB-Santé of Rennes (BB-0033-00056), and CeVi/Carnot program

Archeological Significance Testing at 41BX17/271, the Granberg Site: A Multi-Component Site along the Salado Creek in Bexar County, Texas

The Center for Archaeological Research (CAR) of The University of Texas at San Antonio conducted archeological significance testing at 41BX17, the Granberg Site, from January to March 2006. The testing was conducted for the Texas Department of Transportation, Environmental Affairs Division (TxDOT-ENV). The Granberg Site sits on the eastern flood terrace of the Salado Creek south of Loop 410 in San Antonio, Bexar County, Texas. Planned road improvements including installation of a storm sewer line and a water main prompted the need to assess whether (1) cultural deposits including human remains still exist after previous testing and (2) if the deposits contribute to the site’s National Register of Historic Places eligibility. The archeological work was conducted under Texas Antiquities Permit No. 4010. Steve A. Tomka served as Principal Investigator and Jennifer Thompson served as Project Archeologist. Fieldwork included mechanical auger boring and backhoe trenching to determine the horizontal extent of the site boundaries within the median of Loop 410 eastbound. Sixteen 1-x-1-m units were excavated to determine the distribution and integrity of the cultural deposits and to locate any possible burials that may still exist at the site. Materials recovered included burned rock features, chipped stone artifacts, animal bone, snail and mussel shell and charred plant remains. The distribution of the artifacts, the geomorphic investigations, the radiocarbon assays, and temporally diagnostic artifacts indicate the presence of Middle and Late Archaic archeological materials with good stratigraphic integrity. The Granberg Site was determined to be ineligible for the National Register of Historic Places. Following the completion of eligibility testing efforts, the TxDOT directed the CAR to develop a research design linking the data recovered from the various excavations at the Granberg Site with research goals. The CAR developed the research design (Munoz et al. 2007) under Work Authorization No. 57513SA005 with Cynthia M. Munoz serving as Project Archeologist. At roughly the time of the research design implementation, the CAR was the recipient of a donation of a collection of commingled human skeletal remains recovered from the Granberg Site. These remains were recovered from 41BX17/271 in 1962 by Harvey Kohnitz, an avocational archeologist, without knowledge or permission from the Texas Highway Department. The remains were stored at the Kohnitz home until his son, Mark Kohnitz, donated them to the CAR in 2007. An osteological analysis was conducted at the CAR laboratory during February 2008 for TxDOT, under Work Authorization No. 57513SA005 Supplemental Work Authorization No. 4. The results of this analysis are reported in Appendix H of this report. The commingled remains will be curated the CAR and all required documents, including an inventory, will be submitted to the National Park Service National NAGPRA Program to fulfill all obligations pertaining to the NAGPRA laws. All artifacts collected during this project and all project-associated documentation are permanently curated at the CAR according to Texas Historical Commission guidelines

Fire in Australian savannas: From leaf to landscape

© 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd. Savanna ecosystems comprise 22% of the global terrestrial surface and 25% of Australia (almost 1.9 million km2) and provide significant ecosystem services through carbon and water cycles and the maintenance of biodiversity. The current structure, composition and distribution of Australian savannas have coevolved with fire, yet remain driven by the dynamic constraints of their bioclimatic niche. Fire in Australian savannas influences both the biophysical and biogeochemical processes at multiple scales from leaf to landscape. Here, we present the latest emission estimates from Australian savanna biomass burning and their contribution to global greenhouse gas budgets. We then review our understanding of the impacts of fire on ecosystem function and local surface water and heat balances, which in turn influence regional climate. We show how savanna fires are coupled to the global climate through the carbon cycle and fire regimes. We present new research that climate change is likely to alter the structure and function of savannas through shifts in moisture availability and increases in atmospheric carbon dioxide, in turn altering fire regimes with further feedbacks to climate. We explore opportunities to reduce net greenhouse gas emissions from savanna ecosystems through changes in savanna fire management

Search for Early Pancreatic Cancer Blood Biomarkers in Five European Prospective Population Biobanks Using Metabolomics

Most patients with pancreatic cancer present with advanced disease and die within the first year after diagnosis. Predictive biomarkers that signal the presence of pancreatic cancer in an early stage are desperately needed. We aimed to identify new and validate previously found plasma metabolomic biomarkers associated with early stages of pancreatic cancer. Prediagnostic blood samples from individuals who were to receive a diagnosis of pancreatic cancer between 1 month and 17 years after sampling (N = 356) and age-and sex-matched controls (N = 887) were collected from five large population cohorts (HUNT2, HUNT3, FINRISK, Estonian Biobank, Rotterdam Study). We applied proton nuclear magnetic resonance-based metabolomics on the Nightingale platform. Logistic regression identified two interesting hits: glutamine (P = 0.011) and histidine (P = 0.012), with Westfall-Young family-wise error rate adjusted P values of 0.43 for both. Stratification in quintiles showed a 1.5-fold elevated risk for the lowest 20% of glutamine and a 2.2-fold increased risk for the lowest 20% of histidine. Stratification by time to diagnosis suggested glutamine to be involved in an earlier process (2 to 5 years before diagnosis), and histidine in a process closer to the actual onset (Peer reviewe

Search for Early Pancreatic Cancer Blood Biomarkers in Five European Prospective Population Biobanks Using Metabolomics

Most patients with pancreatic cancer present with advanced disease and die within the first year after diagnosis. Predictive biomarkers that signal the presence of pancreatic cancer in an early stage are desperately needed. We aimed to identify new and validate previously found plasma metabolomic biomarkers associated with early stages of pancreatic cancer. Prediagnostic blood samples from individuals who were to receive a diagnosis of pancreati

Asymmetric response of forest and grassy biomes to climate variability across the African Humid Period : influenced by anthropogenic disturbance?

A comprehensive understanding of the relationship between land cover, climate change and disturbance dynamics is needed to inform scenarios of vegetation change on the African continent. Although significant advances have been made, large uncertainties exist in projections of future biodiversity and ecosystem change for the world's largest tropical landmass. To better illustrate the effects of climate–disturbance–ecosystem interactions on continental‐scale vegetation change, we apply a novel statistical multivariate envelope approach to subfossil pollen data and climate model outputs (TraCE‐21ka). We target paleoenvironmental records across continental Africa, from the African Humid Period (AHP: ca 14 700–5500 yr BP) – an interval of spatially and temporally variable hydroclimatic conditions – until recent times, to improve our understanding of overarching vegetation trends and to compare changes between forest and grassy biomes (savanna and grassland). Our results suggest that although climate variability was the dominant driver of change, forest and grassy biomes responded asymmetrically: 1) the climatic envelope of grassy biomes expanded, or persisted in increasingly diverse climatic conditions, during the second half of the AHP whilst that of forest did not; 2) forest retreat occurred much more slowly during the mid to late Holocene compared to the early AHP forest expansion; and 3) as forest and grassy biomes diverged during the second half of the AHP, their ecological relationship (envelope overlap) fundamentally changed. Based on these asymmetries and associated changes in human land use, we propose and discuss three hypotheses about the influence of anthropogenic disturbance on continental‐scale vegetation change