The premise of this article is that climate effects on lakes can be quantified most effectively by the integration of process-oriented limnological studies with paleolimnological research, ...particularly when both disciplines operate within a common conceptual framework. To this end, the energy (E)—mass (m) flux framework (Em flux) is developed and applied to selected retrospective studies to demonstrate that climate variability regulates lake structure and function over diverse temporal and spatial scales through four main pathways: rapid direct transfer of E to the lake surface by irradiance, heat, and wind; slow indirect effects of E via changes in terrestrial development and subsequent m subsidies to lakes; direct influx of m as precipitation, particles, and solutes from the atmosphere; and indirect influx of water, suspended particles, and dissolved substances from the catchment. Sedimentary analyses are used to illustrate the unique effects of each pathway on lakes but suggest that interactions among mechanisms are complex and depend on the landscape position of lakes, catchment characteristics, the range of temporal variation of individual pathways, ontogenetic changes in lake basins, and the selective effects of humans on m transfers. In particular, preliminary synthesis suggests that m influx can overwhelm the direct effects of E transfer to lakes, especially when anthropogenic activities alter m subsidies from catchments.
Sharpening of optical spectra caused by commensurate growth of an organic adlayer on salt single crystals is reported. The structure is elucidated by atomic force microscopy and advanced potential ...energy calculations. Continued deposition or annealing induces a rearrangement of the molecular monolayer into 3D crystallites, demonstrating the crucial role of the Coulomb interaction with the substrate to form the unexpected commensurate structure.
The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) is a complete blind survey of the Virgo cluster covering similar to 40 sq. deg in the far UV (FUV, lambda(eff) = 1539 angstrom, Delta lambda = 442 ...angstrom) and similar to 120 sq. deg in the near UV (NUV, lambda(eff) = 2316 angstrom, Delta lambda = 1060 angstrom). The goal of the survey is to study the ultraviolet (UV) properties of galaxies in a rich cluster environment, spanning a wide luminosity range from giants to dwarfs, and regardless of prior knowledge of their star formation activity. The UV data will be combined with those in other bands (optical: NGVS; far-infrared - submm: HeViCS; HI: ALFALFA) and with our multizone chemo-spectrophotometric models of galaxy evolution to make a complete and exhaustive study of the effects of the environment on the evolution of galaxies in high density regions. We present here the scientific objectives of the survey, describing the observing strategy and briefly discussing different data reduction techniques. Using UV data already in-hand for the central 12 sq. deg we determine the FUV and NUV luminosity functions of the Virgo cluster core for all cluster members and separately for early-and late-type galaxies and compare it to the one obtained in the field and other nearby clusters (Coma, A1367). This analysis shows that the FUV and NUV luminosity functions of the core of the Virgo clusters are flatter (alpha similar to -1.1) than those determined in Coma and A1367. We discuss the possible origin of this difference.
Aims
The spread of bacteria that are simultaneously resistant to disinfectants and antimicrobials would constitute an unsettling scenario. In order to explore an association between antimicrobial ...resistance and reduced susceptibility to biocides/microbicides (disinfectants) in agriculture, we investigated Escherichia coli (n = 438) and enterococci (n = 120) isolated from six different flocks of the same poultry farm with known history of antimicrobial treatment.
Methods and Results
Susceptibility to disinfectants (formic acid and a quaternary ammonium compound (QAC), didecyldimethylammoniumchloride—DDAC) was assessed by macrodilution according to guidelines of the German Veterinary Society. Escherichia coli, Enterococcus faecalis and Enterococcus faecium were screened (i) for reduced biocide susceptibility and (ii) for an association of biocide susceptibility and antimicrobial resistance including the production of extended‐spectrum beta‐lactamases (ESBL) and the hyperproduction of AmpC‐type beta‐lactamases. DDAC inhibited ESBL/AmpC(hyper)‐producing E. coli (n = 53) from poultry at similar or slightly lower inhibitory concentrations, compared with non‐ESBL/AmpC strains (median MIC = 0·36 vs 1·44 mg l−1). In contrast, DDAC‐MICs were positively correlated with several other antibiotic MICs (e.g. piperacillin and sulphamethoxazole + trimethoprim in E. coli, chloramphenicol in E. faecalis) and increased DDAC‐MICs were statistically linked to high‐level aminoglycoside resistance in enterococci (streptomycin high level). DDAC‐MICs did not correlate with the presence of the integron marker qacEDelta1.
Conclusions
This study provides indication that residual disinfectant might be able to select antimicrobial‐resistant enterococci, but not ESBL‐/AmpC (hyper)producing E. coli from poultry.
Significance and Impact of the Study
While ESBL‐/AmpC‐E. coli were inhibited at disinfectant concentrations comparable to or lower than wildtype values, low concentrations of QACs might be able to select other antimicrobial‐resistant E. coli or enterococci—a finding with special significance for the food processing industry, where QACs are regularly used.
Long sediment cores recovered from the deep portions of Lake Titicaca are used to reconstruct the precipitation history of tropical South America for the past 25,000 years. Lake Titicaca was a deep, ...fresh, and continuously overflowing lake during the last glacial stage, from before 25,000 to 15,000 calibrated years before the present (cal yr B.P.), signifying that during the last glacial maximum (LGM), the Altiplano of Bolivia and Peru and much of the Amazon basin were wetter than today. The LGM in this part of the Andes is dated at 21,000 cal yr B.P., approximately coincident with the global LGM. Maximum aridity and lowest lake level occurred in the early and middle Holocene (8000 to 5500 cal yr B.P.) during a time of low summer insolation. Today, rising levels of Lake Titicaca and wet conditions in Amazonia are correlated with anomalously cold sea-surface temperatures in the northern equatorial Atlantic. Likewise, during the deglacial and Holocene periods, there were several millennial-scale wet phases on the Altiplano and in Amazonia that coincided with anomalously cold periods in the equatorial and high-latitude North Atlantic, such as the Younger Dryas.
Most radiative transfer models assume that dust in spiral galaxies is distributed exponentially. In this paper our goal is to verify this assumption by analysing the two-dimensional large-scale ...distribution of dust in galaxies from the DustPedia sample. For this purpose, we have made use of Herschel imaging in five bands, from 100 to 500 μm, in which the cold dust constituent is primarily traced and makes up the bulk of the dust mass in spiral galaxies. For a subsample of 320 disc galaxies, we successfully performed a simultaneous fitting with a single Sérsic model of the Herschel images in all five bands using the multi-band modelling code GALFITM. We report that the Sérsic index n, which characterises the shape of the Sérsic profile, lies systematically below 1 in all Herschel bands and is almost constant with wavelength. The average value at 250 μm is 0.67 ± 0.37 (187 galaxies are fitted with n250 ≤ 0.75, 87 galaxies have 0.75 < n250 ≤ 1.25, and 46 – with n250 > 1.25). Most observed profiles exhibit a depletion in the inner region (at r < 0.3−0.4 of the optical radius r25) and are more or less exponential in the outer part. We also find breaks in the dust emission profiles at longer distances (0.5−0.6) r25 which are associated with the breaks in the optical and near-infrared. We assumed that the observed deficit of dust emission in the inner galaxy region is related to the depression in the radial profile of the HI surface density in the same region because the atomic gas reaches high enough surface densities there to be transformed into molecular gas. If a galaxy has a triggered star formation in the inner region (for example, because of a strong bar instability, which transfers the gas inwards to the centre, or a pseudobulge formation), no depletion or even an excess of dust emission in the centre is observed.
Ni:Al laminate composites were fabricated by repeatedly cold-rolling Al and Ni foils that were stacked together with initial thicknesses of 25 and 18 μm, respectively. The rolling process consisted ...of multiple 50 % thickness reductions wherein the first reduction was followed by cutting, restacking, and rerolling to achieve a total of three, six or nine 50 % thickness reductions. However, some of the laminates also received a more mild series of six 20 % thickness reductions without restacking. An analysis program was written and used to quantify the distribution of layer thicknesses, bilayer thicknesses and local chemistries for the complex laminate microstructures, while also preserving positional information for the constituent layers. The resulting distributions show that while we see no clustering of very large bilayers in any of the composites, the heavily rolled laminates with only 50 % thickness reductions have a higher percentage of very large bilayers, relative to the volume mean bilayer, compared to laminates with the additional 20 % thickness reductions. This phenomenon is attributed to less uniform layer deformation and more layer pinch-off with 50 % thickness reductions compared to the more gradual 20 % thickness reductions. Differential scanning calorimetry was performed on the laminates to determine the exothermic peak temperatures and the total energy released during controlled heating. Peak temperatures correlate with the volume average bilayer thickness, while the energy release correlates with the bilayer thickness distribution. The velocity and maximum temperature of self-propagating reactions were measured for the laminates and were found to vary according to processing conditions but not according to the volume average bilayer thickness. Foils with 20 % thickness reductions have both hotter and faster reactions compared to samples with only 50 % thickness reductions. The distributions of layer thicknesses, bilayer thicknesses, and local chemistries within the laminates are used to predict the maximum temperature during reaction. The velocities of the unsteady reaction propagations, though, could not be predicted effectively, at least with current analytical models.
Aims. We examine whether dust mass can trace the total or molecular gas mass in late-type Virgo cluster galaxies, and how the environment affects the dust-to-gas ratio and the molecular fraction. ...Methods. Using the far-infrared emission, as observed by the Herschel Virgo Cluster Survey (HeViCS), and the integrated HI 21-cm and CO J = 1-0 line brightness, we infer the dust and total gas mass for a magnitude limited sample of 35 metal rich spiral galaxies. Environmental disturbances on each galaxy are considered by means of the HI deficiency parameter. Results. The CO flux correlates tightly and linearly with far-infrared fluxes observed by Herschel, especially with the emission at 160, 250 and 350 mu m. Molecules in these galaxies are more closely related to cold dust rather than to dust heated by star formation or to optical/NIR brightness. We show that dust mass establishes a stronger correlation with the total gas mass than with the atomic or molecular component alone. The correlation is non-linear since lower mass galaxies have a lower dust-to-gas ratio. The dust-to-gas ratio increases as the HI deficiency increases, but in highly HI deficient galaxies it stays constant. Dust is in fact less affected than atomic gas by weak cluster interactions, which remove most of the HI gas from outer and high latitudes regions. Highly disturbed galaxies, in a dense cluster environment, can instead loose a considerable fraction of gas and dust from the inner regions of the disk keeping constant the dust-to-gas ratio. There is evidence that the molecular phase is also quenched. This quencing becomes evident by considering the molecular gas mass per unit stellar mass. Its amplitude, if confirmed by future studies, highlights that molecules are missing in Virgo HI deficient spirals, but to a somewhat lesser extent than dust.
Lipids are a class of molecules that play an important role in cellular structure and metabolism in all cell types. In the last few decades, it has been reported that long-chain fatty acids (FAs) are ...involved in several biological functions from transcriptional regulation to physiological processes. Several fatty acids have been both positively and negatively implicated in different biological processes in skeletal muscle and other tissues. To gain insight into biological processes associated with fatty acid content in skeletal muscle, the aim of the present study was to identify differentially expressed genes (DEGs) and functional pathways related to gene expression regulation associated with FA content in cattle.
Skeletal muscle transcriptome analysis of 164 Nellore steers revealed no differentially expressed genes (DEGs, FDR 10%) for samples with extreme values for linoleic acid (LA) or stearic acid (SA), and only a few DEGs for eicosapentaenoic acid (EPA, 5 DEGs), docosahexaenoic acid (DHA, 4 DEGs) and palmitic acid (PA, 123 DEGs), while large numbers of DEGs were associated with oleic acid (OA, 1134 DEGs) and conjugated linoleic acid cis9 trans11 (CLA-c9t11, 872 DEGs). Functional annotation and functional enrichment from OA DEGs identified important genes, canonical pathways and upstream regulators such as SCD, PLIN5, UCP3, CPT1, CPT1B, oxidative phosphorylation mitochondrial dysfunction, PPARGC1A, and FOXO1. Two important genes associated with lipid metabolism, gene expression and cancer were identified as DEGs between animals with high and low CLA-c9t11, specifically, epidermal growth factor receptor (EGFR) and RNPS.
Only two out of seven classes of molecules of FA studied were associated with large changes in the expression profile of skeletal muscle. OA and CLA-c9t11 content had significant effects on the expression level of genes related to important biological processes associated with oxidative phosphorylation, and cell growth, survival, and migration. These results contribute to our understanding of how some FAs modulate metabolism and may have protective health function.
The long-term climatic and environmental history of Southeast Asia, and of Thailand in particular, is still fragmentary. Here we present a new 14C-dated, multi-proxy sediment record (TOC, C/N, CNS ...isotopes, Si, Zr, K, Ti, Rb, Ca elemental data, biogenic silica) for Lake Kumphawapi, the second largest natural lake in northeast Thailand. The data set provides a reconstruction of changes in lake status, groundwater fluctuations, and catchment run-off during the Holocene. A comparison of multiple sediment sequences and their proxies suggests that the summer monsoon was stronger between c. 9800 and 7000 cal yr BP. Lake status and water level changes around 7000 cal yr BP signify a shift to lower effective moisture. By c. 6500 cal yr BP parts of the lake had been transformed into a peatland, while areas of shallow water still occupied the deeper part of the basin until c. 5400–5200 cal yr BP. The driest interval in Kumphawapi's history occurred between c. 5200 and 3200 cal yr BP, when peat extended over large parts of the basin. After 3200 cal yr BP, the deepest part of the lake again turned into a wetland, which existed until c. 1600 cal yr BP. The observed lake-level rise after 1600 cal yr BP could have been caused by higher moisture availability, although increased human influence in the catchment cannot be ruled out. The present study highlights the use of multiple sediment sequences and proxies to study large lakes, such as Lake Kumphawapi in order to correctly assess the time transgressive response to past changes in hydroclimate conditions. Our new data set from northeast Thailand adds important palaeoclimatic information for a region in Southeast Asia and allows discussing Holocene monsoon variability and ITCZ movement in greater detail.
► New high resolution 14C-dated, multi-proxy lake sediment sequences. ► Palaeoenvironmental and palaeoclimatic reconstruction for northeast Thailand. ► Summer monsoon was strong >9800–7000 cal yr BP and weak c. 5200–3200 cal yr BP. ► Past monsoon variability is discussed and evaluated in a wider regional context.
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