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111.
Pascal D. Leroy Ahmed Sabri Fran?ois J. Verheggen Fr��d��ric Francis Philippe Thonart Eric Haubruge 《Chemoecology》2011,21(3):113-122
In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects,
plants and hosts for parasitoids or prey for predators. These volatile compounds act as messengers within or between insect
species, inducing particular behaviours, such as the localisation of a source of food, the orientation to an adequate oviposition
site, the selection of a suitable breeding site and the localisation of hosts or prey. In this sense, bacteria have been shown
to play an important role in the production of volatile compounds which ones act as semiochemicals. This review, focusing
on the semiochemically mediated interactions between bacteria and insects, highlights that bacterial semiochemicals act as
important messengers for insects. Indeed, in most of the studies reported here, insects respond to specific volatiles emitted
by specific bacteria hosted by the insect itself (gut, mouthparts, etc.) or present in the natural environment where the insect
evolves. Particularly, bacteria from the families Enterobacteriaceae, Pseudomonaceae and Bacillaceae are involved in many
interactions with insects. Because semiochemicals naturally produced by bacteria could be a very interesting option for pest
management, advances in this field are discussed in the context of biological control against insect pests. 相似文献
112.
113.
Elaine S. Carvalho Rubén J. Sánchez Maria I. B. Tavares álano C. Lam?nica 《Journal of Polymers and the Environment》2010,18(4):661-667
The chemical modification of Acrylamidomethyl Cellulose Acetate Propionate (AMCAP) was carried out by radical addition of
acrylic acid. The structural modification was confirmed with the aid of FTIR, MS and NMR techniques. Thermal properties of
hydrophilic cellulose derivative (AMCAP–H2O2) such as glass transition (Tg 153 °C) and thermal stability (372.7 °C) were determined by DSC and TGA techniques, respectively. These thermal properties
confirmed the introduction of carboxylic groups into AMCAP structure, which causes an impact in their properties. The AMCAP–H2O2 shows minor contact angle compared to AMCAP, giving a more hydrophilic characteristic, due to acrylic acid addition into
the side chains of AMCAP polymer. 相似文献
114.
We report observations of disappearance of Erica tetralix in wet heathland, which is unlikely to be caused by competition, as E. tetralix is dying before its place is taken up by other species. To investigate the causes, we used both old and new data. Results showed that presence of Molinia caerulea and Calluna vulgaris were substantial in the former E. tetralix dominated areas. Measurements of the C/N ratio in the morlayer were between 21 and 26 under the E. tetralix stands. As the expected C/N ratio in a healthy nutrient poor ecosystem like the E. tetralix wet heathland is around 30, this indicates that the ratio is probably decreasing and, correspondingly, the probability of nitrogen leaching from the ecosystem is increasing. The morlayer pH was extremely low—between 3.03 and 3.78. This represents a pH decline since the 1960s, where pH values generally were above 4. This supports the hypothesis that the decrease in morlayer pH is the major factor explaining the disappearance of E. tetralix and that measures to increase pH should be considered as part of the recommendations for relevant future management.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-012-0251-z) contains supplementary material, which is available to authorized users. 相似文献115.
Demir S Saral A Ertürk F Kuzu SL Goncaloğlu BI Demir G 《Environmental science and pollution research international》2012,19(5):1503-1514
Introduction
The effect of diurnal changes in strengths of volatile organic compound (VOC) sources on the performances of positive matrix factorization (PMF) and principal component analysis (PCA) was investigated using ambient measurement results that were taken during daytime and nighttime hours between March 24 and May 14, 2011, within Davutpasa Campus of Yildiz Technical University (Istanbul, Turkey).Methods
Forty-five VOC species, ranging from C5 to C11 in volatility, were measured in the samples, 40 of which are included in the analyses. Ambient samples were grouped as daytime, nighttime, and all day datasets, and both PMF and PCA were applied to each dataset. A total of six source groups were extracted from each dataset: solvent use, general industrial paint use, gasoline and diesel vehicle exhausts, and biogenic as well as evaporative emissions. Estimated source contributions showed great diurnal variations.Results
The results suggested that extraction of possible sources by PCA depends greatly on the number of samples and the strength of the sources, while PMF produced stable results regardless of number of samples and source strengths.Conclusion
Although PMF was unable to resolve gasoline vehicle and evaporative emissions, it was found to be successful in explaining diurnal fluctuations in source strengths, while the performance of PCA depends on the strength of emission source. 相似文献116.
Kauppi S Romantschuk M Strömmer R Sinkkonen A 《Environmental science and pollution research international》2012,19(1):53-63
Purpose
Prevalence of organic pollutants or their natural analogs in soil is often assumed to lead to adaptation in the bacterial community, which results in enhanced bioremediation if the soil is later contaminated. In this study, the effects of soil type and contamination history on diesel oil degradation and bacterial adaptation were studied. 相似文献117.
Community-based collaborative groups involved in public natural resource management are assuming greater roles in planning,
project implementation, and monitoring. This entails the capacity of collaborative groups to develop and sustain new organizational
structures, processes, and strategies, yet there is a lack of understanding what constitutes collaborative capacity. In this
paper, we present a framework for assessing collaborative capacities associated with community-based public forest management
in the US. The framework is inductively derived from case study research and observations of 30 federal forest-related collaborative
efforts. Categories were cross-referenced with literature on collaboration across a variety of contexts. The framework focuses
on six arenas of collaborative action: (1) organizing, (2) learning, (3) deciding, (4) acting, (5) evaluating, and (6) legitimizing.
Within each arena are capacities expressed through three levels of social agency: individuals, the collaborative group itself,
and participating or external organizations. The framework provides a language and set of organizing principles for understanding
and assessing collaborative capacity in the context of community-based public forest management. The framework allows groups
to assess what capacities they already have and what more is needed. It also provides a way for organizations supporting collaboratives
to target investments in building and sustaining their collaborative capacities. The framework can be used by researchers
as a set of independent variables against which to measure collaborative outcomes across a large population of collaborative
efforts. 相似文献
118.
In many regions of the world, fires are primarily of anthropogenic origin. In northwestern Patagonia, the number of fires
is not correlated with meteorological variables, but is concentrated in urban areas. This study was conducted in the wildland–urban
interface (WUI) area of San Carlos de Bariloche (Patagonia, Argentina), within the Nahuel Huapi National Park. WUI fires are
particularly problematic because, besides people and goods, they represent a danger to protected areas. We studied the relationship
between fire records and socioeconomic indicators within the WUI of San Carlos de Bariloche. We conducted a Multiple Correspondence
Factorial Analysis and an Ascendant Hierarchical Classification of the city neighborhoods. The results show that the neighborhoods
in Bariloche can be divided into three classes: High Socioeconomic Fire Risk neighborhoods, including neighborhoods with the
highest fire rates, where people have low instruction level, high levels of unsatisfied basic needs and high unemployment
levels; Low Socioeconomic Fire Risk neighborhoods, that groups neighborhoods which present the opposite characterization,
and Moderate Socioeconomic Fire Risk neighborhoods, which are more heterogeneous. Once neighborhoods were classified, a Socioeconomic
Fire Risk map was generated, supplementing the existing WUI Fire Danger map. Our results emphasize the relevance of socioeconomic
variables to fire policies. 相似文献
119.
The concentrations of heavy metals and metals (Zn, Pb, Bi, Cd, Ni, Co, Fe, Mn, Mg, Cu, Cr, Ca, Sr, Na, Li, K) were measured in muscle of five species Cyprinus carpio (from I??kl? dam), Scardinius erythrophthalmus (from I??kl? dam), Tinca tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), Carassius carassius (from Karaca?ren dam) caught from I??kl? and Karaca?ren. The highest metal was Na (466.95 μg/g) in C. carassius, while the lowest levels were Fe (0.37 μg/g) and Cu (0.37 μg/g) in C. carpio from I??kl? dam. The mean concentrations μg/g d.w. some of heavy metals in muscle of C. carpio (from I??kl? dam), S. erythrophthalmus (from I??kl? dam), T. tinca (from I??kl? dam), C. carpio (from Karaca?ren dam), C. carassius (from Karaca?ren dam) were as follows: Cd 2.00-2.10-1.95-2.06-2.27, Zn 4.36-2.64-13.13-13.33-24.47, Pb 1.65-1.24-1.90-2.37-2.41, Co 2.46-2.37-2.48-2.58-2.80, Mg 138.51-154.35-218.59-204.58-202.16, Fe 0.37-2.62-3.17-3.01-12.33, respectively. 相似文献
120.
Sediment quality guidelines (SQGs) can be derived using different approaches and are commonly used in environmental management,
reclamation, and risk assessment. The screening-level concentration (SLC) approach has been used in Ontario, Canada, to derive
lowest effect levels (LELs) and severe effect levels for use as SQGs. This approach was adopted by the Canadian Nuclear Safety
Commission (CNSC) to set guidelines for metals (As, Cr, Cu, Pb, Mo, Ni, Se, U, and V) and radionuclides (Ra-226, Pb-210, and
Po-210) in sediment at northern Saskatchewan uranium mining and milling operations. The SLC approach is based on total metal
and radionuclide concentrations in sediment, and corresponding benthic community composition data for a specific sampling
site. In this study, sediment chemistry (total metals and radionuclides) and benthic community data from northern Saskatchewan
uranium operations were compiled and examined. Results indicate that the CNSC-derived SQGs had limited relationships to observed
effects, or lack thereof, on benthic invertebrate communities near uranium operations in Saskatchewan. The LELs were found
to correctly align with effects at 95% of the sites that had effects, on a general basis, but on an element-specific basis
many of the elements had concentrations at effect sites below their LELs. Furthermore, concentrations of the evaluated elements
exceeded at least one LEL at 60% of the no-effect sites. The high number of exceedences of LELs at reference and no-effect
sites (false-positives) calls to question the appropriateness of the CNSC-derived SQGs. It is suggested that alternatives
to the SLC approach be explored. 相似文献