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91.
92.
A perfluorooctane sulfonic acid (PFOS) assessment was conducted on gibel carp (Carassius auratus gibelio), carp (Cyprinus carpio), and eel (Anguilla anguilla) in Flanders (Belgium). The liver PFOS concentrations in fish from the Ieperlee canal (Boezinge, 250-9031 ng/g wet weight, respectively) and the Blokkersdijk pond (Antwerp, 633-1822 ng/g wet weight) were higher than at the Zuun basin (Sint-Pieters-Leeuw, 11.2-162 ng/g wet weight) and among the highest in feral fish worldwide. Eel from the Oude Maas pond (Dilsen-Stokkem) and Watersportbaan basin (Ghent) had PFOS concentrations ranging between 212 and 857 ng/g wet weight. The hepatic PFOS concentration was significantly and positively related with the serum alanine aminotransferase activity, and negatively with the serum protein content in eel and carp. The hepatic PFOS concentration in carp correlated significantly and negatively with the serum electrolyte concentrations whereas a significant positive relation was found with the hematocrit in eel. Although 13 organochlorine pesticides, 22 polychlorinated biphenyl (PCB) congeners and 7 polybrominated diphenyl ethers (PBDEs) were also measured in the liver tissue, only PCB 28, PCB 74, gamma-hexachlorocyclohexane (gamma-HCH) and hexachlorobenzene (HCB) were suggested to contribute to the observed serological alterations in eel.  相似文献   
93.
Abstract: The controversy among Karl and Bowen (1999) , Pritchard (1999) , and Grady and Quattro (1999) over scientific uncertainties and the ethical and political consequences of the black turtle's taxonomic status is caused by incomplete and uncertain scientific knowledge. When faced with cases of uncertainty, conservation biologists need to use ethical rationality, not merely scientific rationality. They should follow three general ethical principles: (1) perform and present unbiased research, (2) promote use of unbiased research by others, and (3) protect human and environmental welfare. Adhering to these principles is difficult because they can conflict, are too general to provide specific guidance in a particular situation, and are not ranked according to which ought to take priority in different situations. One way to deal with these difficulties is to employ a two-stage ethical analysis. This analysis develops general principles (first stage) and then investigates the consequences of adopting each of the principles (second stage). A two-stage ethical analysis applied to the controversy over the black turtle's taxonomic status suggests that even if there are some grounds for expanding conservation biologists' responsibilities to human and environmental welfare, they are not ethically justified in using any means whatsoever to achieve desirable consequences when the public has rights to full information. Conservation biologists do not appear to have grounds for paternalism in this case because it involves value judgments, not merely professional expertise.  相似文献   
94.
Hypotheses about the evolution of gregariousness and social organisation in primates are based on ecological explanations as well as on social factors such as conspecific threat (especially infanticide by males). The social explanation fits well with the conditions found in strepsirrhine primates and furthermore explains why infanticide in anthropoid primates living in one-male groups mainly occurs when the resident male (protector) is replaced. However, whether it likewise fits to the conditions in multimale groups will depend on the role of resident males as infant protectors, which has rarely been examined. We investigated long-term data of wild Hanuman langurs (Presbytis entellus) inhabiting a forest near the village of Ramnagar (southern Nepal). Twenty-two eye-witnessed attacks on infants by males were analysed in connection with male residency, paternity (DNA analyses) and sexual behaviour. Adult males played a major role in infant defence (65%). Only the genetic father or males who had been residents when the infant was conceived were observed to protect infants. Males who immigrated after a female had conceived may later attack her infant and were never observed to defend it. lt seems that the males took only copulations with potentially fertile females but not with pregnant females as clues for paternity. In the light of these results it seems likely that the risk of infanticide is an important determinant in female-male associations even in anthropoid primate multimale groups. Received: 22 December 1998 / Received in revised form: 30 April 1999 / Accepted: 1 May 1999  相似文献   
95.
Amino acids (AAs) are prevalent in source water, particularly during spring run-off. Monitoring of amino acids in source water is desirable for water treatment plants (WTP) to indicate changes in source water quality. The objective of this study was to establish analytical procedures for reliable monitoring of amino acids in source water. Therefore, we examined two different methods, large volume inject (LVI) and solid phase extraction (SPE), for sample preparation prior to HILIC-MS/MS. The LVI-HILIC-MS/MS method can provide fast and sensitive detection for clean samples, but suffers from matrix effects, resulting in irreproducible separation and shortening column lifetime. We have demonstrated that SPE was necessary prior to HILIC-MS/MS to achieve reproducible and reliable quantification of AAs in source water. A natural heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCCA) was also included in the method to indicate changes in other natural nitrogenous compounds in source water. The SPE-HILIC-MS/MS method was able to achieve limits of detection from 2.6-3400 ng/L for the amino acids and MTCCA with RSDs (n=3) of 1.1%-4.8%. As well, retention times (RT) of the analytes were reproducible with variation less than 0.01 min (n=3) through the entire project. We further applied the SPE-HILIC-MS/MS method to determine AAs in authentic source water samples collected from two drinking water treatment plants (WTPs) during the 2021 spring run-off season. The results support that the SPE-HILIC-MS/MS method does not require derivatization and can provide reliable, accurate, and robust analysis of AAs and MTCCA in source water, supporting future monitoring of source water quality.  相似文献   
96.
Bunte, Kristin, John P. Potyondy, Kurt W. Swingle, and Steven R. Abt, 2012. Spatial Variability of Pool-Tail Fines in Mountain Gravel-Bed Stream Affects Grid-Count Results. Journal of the American Water Resources Association (JAWRA) 48(3): 530-545. DOI: 10.1111/j.1752-1688.2011.00629.x Abstract: Fine sediment (<2 and <6 mm) particles underlying a 49-intersection grid placed on a streambed at 25, 50, and 75% of the wetted pool-tail width are commonly counted to assess the status and trend of aquatic ecosystems or to monitor changes in the supply of fines in mountain gravel-bed streams. However, results vary even when crews perform nearly identical procedures. This study hypothesized that spatial variability of pool-tail fines affects grid-count results and that a sampling scheme can be optimized for precision and accuracy. Grid counts taken at seven evenly spaced locations across the wetted width of 10 pool tails in a pool-riffle study stream indicated a bankward fining trend with secondary peaks of fines within the stream center. Sampling locations close to the waterlines harbored more than twice as many fines as central locations. Most of the five grid-count schemes derived from the seven sampled locations produced significantly different results. Compared with sampling at all seven locations, schemes that focus near waterlines overpredicted fines, while those that focus on the center underpredicted them. Variability of fines among pool tails was the highest within a broad band along the waterlines; hence, focusing sampling there yielded the most variable results. The scheme sampling at 25, 50, and 75% of the wetted width had the lowest precision and moderate accuracy. Accuracy and precision of grid-count results can be greatly improved by sampling at seven even-spaced locations across the pool tail.  相似文献   
97.
In this article, we describe how protecting vernal pools was discussed by experts in the northeastern United States (U.S) within the context of a theoretical policy framework. We offer insight about characteristics of feasible vernal pool policy solutions, and identify gaps in our understanding, particularly regarding conditions in states currently lacking specific vernal pool protections. Vernal pools are geographically isolated, intermittent wetlands that provide important habitat for a variety of plants and animals. Many may not be federally protected as a result of judicial decisions over the past two decades, and the rule intended to clarify what qualifies for federal protection is currently being reviewed by the courts. Thus, state or local policy approaches may be alternatives to conserving vernal pools. We interviewed vernal pool experts in the northeastern U.S. regarding approaches to vernal pool protection and analyzed their perceptions through the lens of Kingdon's ( 2011 ) multiple streams policy development framework. The framework denotes 13 characteristics of three processes associated with policy development: problem identification, policy solution development, and the impacts of politics. While analyzed for all 13 components, we found participants most often discussed feasibility of policy formulation and implementation, particularly with regard to protecting vernal pools of high value while also remaining within the bounds of what public opinion supports.  相似文献   
98.
Studies of collaborative watershed groups show that effective leadership is an important factor for success. This research uses data from in-depth interviews and meeting observation to qualitatively examine leadership in a Midwestern collaborative watershed group operating with government funding. One major finding was a lack of role definition for volunteer steering-committee members. Lack of role clarity and decision-making processes led to confusion regarding project management authority among the group, paid project staff members, and agency personnel. Given the important role of government grants for funding projects to protect water quality, this study offers insight into leadership issues that groups with Clean Water Act Section 319 (h) funds may face and suggestions on how to resolve them.  相似文献   
99.
Antler asymmetry and immunity in reindeer   总被引:3,自引:0,他引:3  
Fluctuating asymmetry (FA) measures an individual's ability to undergo identical development in bilaterally symmetrical characters and may indicate sensitivity to environmental stress. FA in ornamental characters is often positively related to parasite intensities, which are important environmental stressors. Parasites affect and are affected by several parts of the immune system, and the ability to resist parasites may be signalled via FA in ornaments. In this study we examined reindeer antlers, which show FA, demonstrated to be caused by parasite infections. We measured antler FA, immune parameters (i.e. densities of different classes of leukocytes, IgG levels and abomasal lymph node numbers) and intensity of abomasal nematodes in free-ranging 1.5-year-old male reindeer slaughtered in the early part of their rutting period. We found a relationship between parasite intensity and immune parameters suggesting that our measures of immune activity reflect density of current parasite infections. More important, these immune parameters were associated with FA in both the main beam length and numbers of antler tines. The immune parameters were, however, only weakly correlated to antler size. This indicates that FA, but not size, of antlers grown during exposure to a multitude of environmental stressors may reveal information about individual immunity that can be important for host-parasite interactions. Antler FA may therefore communicate an individual's quality during the rut in reindeer. Received: 30 March 1998 / Accepted after revision: 15 August 1998  相似文献   
100.
Transport affects climate directly and indirectly through mechanisms that operate on very different timescales and cause both warming and cooling. We calculate contributions to the historical development in global mean temperature for the main transport sectors (road transport, aviation, shipping and rail) based on estimates of historical emissions and by applying knowledge about the various forcing mechanisms from detailed studies. We also calculate the development in future global mean temperature for four transport scenarios consistent with the IPCC SRES scenarios, one mitigation scenario and one sensitivity test scenario. There are large differences between the transport sectors in terms of sign and magnitude of temperature effects and with respect to the contributions from the long- and short-lived components. Since pre-industrial times, we calculate that transport in total has contributed 9% of total net man-made warming in the year 2000. The dominating contributor to warming is CO2, followed by tropospheric O3. By sector, road transport is the largest contributor; 11% of the warming in 2000 is due to this sector. Likewise, aviation has contributed 4% and rail ~1%. Shipping, on the other hand, has caused a net cooling up to year 2000, with a contribution of ?7%, due to the effects of SO2 and NOx emissions. The total net contribution from the transport sectors to total man-made warming is ~15% in 2050, and reaches 20% in 2100 in the A1 and B1 scenarios. For all scenarios and throughout the century, road transport is the dominating contributor to warming. Due to the anticipated reduction in sulphur content of fuels, the net effect of shipping changes from cooling to warming by the end of the century. Significant uncertainties are related to the estimates of historical and future net warming mainly due to cirrus, contrails and aerosol effects, as well as uncertainty in climate sensitivity.  相似文献   
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