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171.
Until recently, little was known about the fungi found in shark gills and their biomedicinal potential. In this article, we described the isolation, bioactivity, diversity, and secondary metabolites of bioactive fungi from the gill of a shark (Carcharodon carcharias). A total of 115 isolates were obtained and grown in 12 culture media. Fifty-eight of these isolates demonstrated significant activity in four antimicrobial, pesticidal, and cytotoxic bioassay models. Four randomly selected bioactive isolates inhibited human cancer cell proliferation during re-screening. These active isolates were segregated into 6 genera using the internal transcribed spacer-large subunit (ITS-LSU) rDNA-sequence BLAST comparison. Four genera, Penicillium, Aspergillus, Mucor, and Chaetomium were the dominant taxa. A phylogenic tree illustrated their intergenera and intragenera genetic diversity. HPLC-DAD-HRMS analysis and subsequent database searching revealed that nine representative strains produced diverse bioactive compound profiles. These results detail the broad range of bioactive fungi found in a shark’s gills, revealing their biopharmaceutical potential. To the best of our knowledge, this is the first study characterizing shark gill fungi and their bioactivity. 相似文献
172.
One of the simplest location models in terms of its constraint structure in location‐allocation modeling is the location set‐covering problem (LSCP). Although there have been a variety of geographic applications of the set‐covering problem (SCP), the use of the SCP as a facility location model is one of the most common. In the early applications of the LSCP, both potential facility sites as well as demand were represented by points discretely located in geographic space. The advent of geographic information systems (GIS), however, has made possible a greater range of object representations that can reduce representation error. The purpose of this article is to outline a methodology using GIS and K = 3 central place lattices to solve the LSCP when demand is continuously distributed over a bounded area and potential facility sites have not been defined a priori. Although, demand is assumed to exist over an area, it is shown how area coverage can be accomplished by the coverage of a point pattern. Potential facility site distributions based on spacings that are powers of one‐third the coverage distance are also shown to provide more efficient coverage than arbitrarily chosen spacings. Using GIS to make interactive adjustments to an incomplete coverage also provides an efficient alternative to smaller spacings between potential facility sites for reducing the number of facilities necessary for complete coverage. 相似文献
173.
Multi-objective optimisation is being increasingly applied in water supply management to identify optimal operating options. However, a key challenge in the implementation of multi-objective optimisation is interpreting the large and multidimensional Pareto-optimal set. This paper shows how cluster, visual and post-optimisation analysis can aid the decision maker in addressing this challenge. This is demonstrated for a case study based on South East Queensland Water Grid, Australia, as part of a broader operational planning framework. Firstly, cluster analysis identifies a smaller set of representative options to aid in visual analysis. Secondly, visual analysis techniques are used to identify the trade-offs between objectives, the relationships between decision variables and objective performance, and to shortlist promising operating options. Finally, post-optimisation analysis techniques identify efficient operating options from the Pareto set, based on decision-maker preferences. Together these techniques can be used to identify a shortlist of operating options, for further consideration using multicriteria analysis. 相似文献
174.
Ocean Dynamics - The approach for modeling bioluminescence (BL) potential is proposed. The approach consists of (1) estimation of the adjoint (by backward in time integration of the adjoint model),... 相似文献
175.
In recent years, a vibrant literature on urban informality has emerged in urban geography. A key claim of this literature is that informality is not only present in cities in the Global South, and that the concept can be usefully applied to understand important dimensions of urbanisation in cities in the Global North. In this paper, we apply insights from that literature to an examination of informality in Australian cities, as a means of deepening our understanding of changes currently underway in urban governance and politics. Drawing on that literature and our own research into informal practices in Australian cities, we examine the forces that help to produce informality, the diverse forms and agents of informality, the forms of authority that they enact, and their relationship to formal economies, regulations and politics. We use examples of informal housing, informal labour, do-it-yourself music venues, graffiti and its regulation, food foraging, and queer community building in Sydney to illustrate our arguments. We conclude by reflecting on the lessons learnt across these diverse cases for our understanding of urban governance and politics in Australia, and offer an agenda for further research on this issue. 相似文献
176.
To remain viable, agricultural producers will need to adapt to changing climatic conditions in coming decades. Agricultural advisers play an important role in helping producers decide to adopt appropriate adaptation practices. Photovisualizations have the potential to complement currently utilized outreach and education strategies. This research uses a focus group approach to explore (1) whether photovisualizations can aid in decision-making about climate change adaptation, and (2) what characteristics of photovisualizations are most effective at conveying spatial aspects of adaptation practices. We found that photovisualizations generate rich discussions about ecological and economic effects as well as tradeoffs associated with climate adaptation practices. To have the greatest impact, photovisualizations should be used when producers are considering implementing high-cost or high-risk projects, when practices are likely to dramatically change the visual landscape, or when a practice is unfamiliar to a producer. 相似文献
177.
Stephanie C. Werner 《Meteoritics & planetary science》2019,54(5):1182-1193
Crater densities on planetary surfaces allow assessing relative ages but so far firm calibration of so‐called cratering‐chronology models is available only for the Moon and limited to the past 4.1 billion years. Most planetary geological time scales are still model‐dependent, and essentially constrained by meteorite ages or by comparison to (dynamical) solar system evolution models. Here we describe in situ calibration of the Martian cratering chronology using cosmogenic and radiogenic isotope ages obtained by the NASA Curiosity rover. We determined the cratering‐rate ratio between Moon and Mars for recent times, and extended the calibration of cratering rates to earlier times than those based exclusively on lunar data. Our preferred interpretation supports monotonic flux decay since at least 4.24 Ga and likely since about 4.45 Ga, implying orbital migration of the giant planets, and its direct, transient, dynamical effect on the planetesimal populations was initiated early. But only Martian Sample Return will provide strongly needed capability for distinction of the different models currently available. 相似文献
178.
N. Kalthoff F. Fiedler M. Kohler O. Kolle H. Mayer A. Wenzel 《Theoretical and Applied Climatology》1999,62(1-2):65-84
Summary During 1992 and 1995 in the Upper Rhine valley between Karlsruhe in the north and Basel in the south 36 energy balance stations
were installed to analyze the spatial and temporal behavior of the components of the energy balance. A second aim of the project
‘Regio-Klima-Projekt’ (REKLIP) was to study the dependence of climatic variables on the energy balance. Three main influences
on spatial variation in energy balance components were detected: orography, precipitation and land use. Concerning the dependence
of the climatic variables on the energy balance it can be stated that the mean diurnal amplitude of temperature shows a good
correlation with the mean diurnal sensible heat flux, while the diurnal amplitude of the specific humidity correlates with
the mean diurnal latent heat flux. Both these results are in good agreement with theoretical considerations. Consequently,
areas with enhanced sensible heat flux values show higher monthly mean temperature maxima and also a greater numbers of summer
days, while areas with higher latent heat flux values indicate enhanced monthly mean humidity maxima.
Received February 26, 1998 Revised June 5, 1998 相似文献
179.
Fluid Inclusion and Stable Isotope Study at the Southeastern Martabe Deposit: Purnama,Barani and Horas Ore Bodies,North Sumatra,Indonesia
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The Martabe Au–Ag deposit, North Sumatra Province, Indonesia, is a high sulfidation epithermal deposit, which is hosted by Neogene sandstone, siltstone, volcanic breccia, and andesite to basaltic andesite of Angkola Formation. The deposit consists of six ore bodies that occurred as silicified massive ore (enargite–luzonite–pyrite–tetrahedrite–tellurides), quartz veins (tetrahedrite–galena–sphalerite–chalcopyrite), banded sulfide veins (pyrite–tetrahedrite–sphalerite–galena) and cavity filling. All ore bodies are controlled by N–S and NW–SE trending faults. The Barani and Horas ore bodies are located in the southeast of the Purnama ore body. Fluid inclusion microthermometry, and alunite‐pyrite and barite‐pyrite pairs sulfur isotopic geothermometry show slightly different formation temperatures among the ore bodies. Formation temperature and salinity of fluid inclusions of the Purnama ore body range from 200 to 260 C and from 6 to 8 wt.% NaCl equivalent, respectively. Formation temperature and salinity of fluid inclusions of the Barani ore body range from 200 to 220 °C and from 0 to 2.5 wt.% NaCl equivalent and those of the Horas ore body range from 240 to 275 °C and from 2 to 3 wt.% NaCl equivalent, respectively. The Barani and Horas ore bodies are less silicified and sulfides are less abundant than the Purnama ore body. A relationship between enthalpy and chloride content indicates mixing of hot saline fluids with cooler dilute fluids during the mineralization of each of the ore bodies. The δ18O values of quartz samples from the southeast ore bodies exhibit a wide range from +4.2 to +12.9‰ with an average value of +7.0‰. The δ18O values of H2O estimated from δ18O values of quartz, barite and calcite confirm the oxygen isotopic shift to near meteoric water trend, which support the incorporation of meteoric water. Salinity of the fluid inclusions decrease from >5 wt.% NaCl equivalent in the Purnama ore body to <3 wt.% NaCl equivalent in the Barani ore body, indicating different fluid systems during mineralization. The δ34S values of sulfide and sulfate in Purnama range from ? 4.2 to +5.5‰ and from +1.2 to +26.7‰, those in the Barani range from ? 4.3 to +26.4‰ and from +3.9 to +18.5‰ and those in the Horas ore body range from ? 11.8 to +3.5‰ and from +1.4 to +25.7‰, respectively. The δ34S of total bulk sulfur in southeastern ore bodies (Σδ34S) was estimated to be approximately +6‰. The estimated sulfur fugacity during formation of the Purnama and Horas ore bodies is relatively high. It was between 10?4.8 and 10?10.8 atm at 220 to 260 °C. Tellurium fugacity was between 10?7.8 and 10?9.5 atm at 260 °C and between 10?9 and 10?10.6 atm at 220 °C in the Purnama ore body. The Barani ore body was formed at lower fS2, lower than about 10?14 atm at 200 to 220 °C based on the presence of arsenopyrite and pyrrhotite in the early stage, and between 10?14 and 10?12 atm based on the existence of enargite and tennantite in the last stage. © 2016 The Society of Resource Geology 相似文献
180.
Matthias Thienemann Stephanie Kusch Hendrik Vogel Benedikt Ritter Enno Schefuî Janet Rethemeyer 《Boreas: An International Journal of Quaternary Research》2019,48(2):287-298
Atmospheric circulation over the North Atlantic has undergone significant fluctuations during the Holocene. To better constrain these changes and their impacts on the Fennoscandian subarctic, we investigated molecular and inorganic proxies as well as plant wax D/H isotopes (δDC28) in a Holocene sedimentary record from Lake Torneträsk (Sweden). These data indicate a thermal maximum c. 8100 to 6300 cal. a BP with reduced soil organic matter input, followed by a long‐term cooling trend with increasing soil erosion. δD data suggest a stable atmospheric circulation with predominance of westerly flow and North Atlantic moisture sourcing during the Early and Middle Holocene. A substantial depletion in δD followed by increased flood frequency starting at c. 5300 cal. a BP and intensifying c. 1500 cal. a BP suggests a reorganization of the atmospheric circulation from zonal towards meridional flow with predominantly Arctic Ocean and Baltic Sea moisture sourcing. 相似文献