The current state of Mediterranean mountain areas has been driven by two main factors: intense traditional human activity
and the dynamics of the ecosystem itself. In this study, we examine land-cover changes in a National Park in the Pyrenees
mountains (NE Iberian Peninsula), which was designated a protected area 55 years ago. First, we have analyzed spatio-temporal
changes in land-cover pattern and forest dynamics from 1957 to 2005. During this period, land-cover dynamics consisted of
two main processes: (i) expansion of the forest area and (ii) increasing cover of forests already present in 1957. To analyze
the role of the conservation level of the park, we have also compared the results obtained within the park with those of unprotected,
peripheral areas. In the two areas with different protection level, dense forests increased throughout the period because
of the reduction in forestry activities. The peripheral area showed a higher rate of forest-cover change from 1957 to 2005
compared to the National Park. This higher increase in forest cover in the peripheral area could be related to a higher proportion
in the National Park of screes and rocky areas and to the decline and transformation of forest activities in these peripheral,
lower elevation areas. 相似文献
Summary The predator,Rhizophagus grandis, is linked to its specific prey,Dendroctonus micans, by semiochemical signals regulating oviposition and long range orientation. A mixture of simple oxygenated monoterpenes [(–)—fenchone, (–)—pinocamphone, rac. camphor, terpinene-4-ol, borneol, fenchol and verbenone], identified from the frass ofD. micans has been found to be extremely active in a flight windtunnel as a long—range attractant for the predator. The mixture elicited 84 % of the response to larval frass of the prey. Excluding pinocamphone from the mixture did not influence its activity. Also, changing the absolute configurations of some of the components (fenchol, terpinene-4-ol and borneol) did not influence the predators' response. However, the addition of (–)—-terpineol increased the attractivity of the synthetic blend to almost that of larval frass of the prey. Ecological implications of the identified semiochemicals and their use in pest management are discussed. 相似文献
Negatively charged carboxymethylated polyethersulfone (CMPES) and positively charged quaternized polyethersulfone (QAPES) ultrafiltration (UF) membranes were prepared by bulk chemical modification and non-solvent induced phase separation method. The effects of PES membrane interfacial electrokinetic property on the bovine serum albumin (BSA) membrane fouling behavior were studied with the aid of the membrane-modified colloidal atomic force microscopy (AFM) probe. Electrokinetic test results indicated that the streaming potential (ΔE) of QAPES membrane was not consistent with its expected IEC value, however, within the pH range of 3–10, the ζ potentials of two charged-modified PES membranes were more stable than the unmodified membrane. When pH value was 3, 4.7 or 9, the interaction behavior between charged PES membrane and BSA showed that there was significant linear correlation between the jump distance r0 of membrane-BSA adhesion force (F/R) and the ζ potential absolute value. Charged modification significantly reduced the adhesion of PES membrane-BSA, and the adhesion data was good linear correlated with the flux decline rate in BSA filtration process, especially reflected in the CMPES membrane. The above experimental facts proved that the charged membrane interfacial electric double layer structure and its electrokinetic property had strong ties with the protein membrane fouling behavior.
When cooking on a barbecue grill, consumers often use aluminum grill pans. For one, the pan catches the fats and oils that would drip into the embers causing the formation of potentially noxious smoke, and the pan also protects the food from being burned by direct heat from the coals. In addition, new aluminum products for use in ovens and grills are becoming increasingly popular. Due to their light weight and excellent heat transfer camping, utensils made of aluminum are, for example, often used by fishermen and mountain climbers. Preparing food in aluminum utensils can, however, result in migration of the aluminum to the foodstuffs.
Results/Conclusions
In this study presented here, it was found that the transfer limit of 5.00 mg/L for aluminum is not exceeded using simulants for oil or for tap water; however, with an aqueous solution of 0.5% citric acid, the limit is clearly exceeded at 638 mg/L. This means that the Tolerable Weekly Intake (TWI) is exceeded by 298% for a child weighing 15 kg and for an adult weighing 70 kg it is equivalent to 63.8% of the TWI, assuming a daily uptake of 10 mL marinade containing lemon juice over a period of 1 week. Preparation of a fish dish with a marinade containing lemon juice in camping dishes would result in the TWI being exceeded by 871% for a child weighing 15 kg and by 187% for an adult weighing 70 kg assuming a daily uptake of 250 g over a period of 1 week.
Markgrafenheide-Hütelmoor covers a total area of 1000 ha (about 490 ha are coastal moor) and a coastline of about 6 km. This touristy area belongs to the city of Rostock in Germany. As response to sea level rise and heavy coastal erosion, the small seaside resort Markgrafenheide received a comprehensive storm surge protection until 2006. Subsequently, the adjacent Hütelmoor was flooded with the aim to restore it as a brackish coastal moor. Coastal protection measures at the Baltic Sea coastline were abandoned to enable natural dynamics, a coastal realignment and salt water intrusions. The entire process until full implementation took 14 years and was associated with very problematic public participation and a strong local polarization. Based on a literature and media review, two surveys, and expert interviews we retrospectively document and analyse the planning process with focus on public information, perception and participation. The local population and holidaymakers did not perceive coastal changes and if, did not associate them with climate change. Interviewees remembered single storm surges, but felt save from it and sea level rise was not perceived as a threat. 89% said that they feel insufficiently informed about the combined coastal protection wetland restoration measure, but did not use the offered information possibilities. 81% had their information from newspapers and freely distributed advertisers. It seems that insufficient information was the major reason for the problems with local acceptance and public participation. The media played a dominating role. The decline of traditional newspapers and the growths of free advertisers seemed to have a negative impact on quality of information and favoured a polarization. Additionally, we discuss local specifics like the cultural background (GDR history), traditions, frustration and the relatively old population and their role in public participation. We strongly promote a pro-active and long-term information and public relation strategy. 相似文献
Feral pigeons are descendants of wild rock pigeons that have adapted to the urban habitat. They have partially conserved the foraging behaviour of their wild ancestors (flights to agricultural areas) but have also developed new habits. Previous studies on the foraging strategies of feral pigeons have given various results, e.g. maximum distances reached by the pigeons (measured in a straight line from the resting places) differed between 0.3–0.5 km and 18–25 km. This study focuses on the spatio-temporal activity of feral pigeons in the urban habitat. We equipped 80 free-living feral pigeons from Basel, Switzerland with GPS receivers. We found three different foraging strategies for pigeons in Basel: (1) in the streets, squares and parks near the home loft, (2) in agricultural areas surrounding the city, (3) on docks and railway lines in harbours. The maximum distance reached by a pigeon was 5.29 km. More than 32% of the pigeons remained within 0.3 km of the home lofts and only 7.5% flew distances of more than 2 km. Females covered significantly longer distances than males, preferring to fly to more abundant and predictable food sources. Temporal activity patterns showed to be influenced by sex, breeding state and season. In contrast to wild rock pigeons and to feral pigeons in other cities, pigeons in Basel showed a clear bimodal activity pattern for breeding birds only. The differences between our results and those of other studies seem to be partly method-dependent, as the GPS-technique allows to record the pigeons’ localisations continuously in contrast to other methods. Other differences might be due to different kinds of food supply in the various cities. Our study shows that feral pigeons have individual foraging strategies and are flexible enough to adapt to different urban environments.Electronic supplementary material Supplementary material is available for this article at 相似文献
Anarchy, where honeybee workers produce males in the presence of a queen, is extremely rare in natural honeybee populations,
suggesting that there are colony-level costs associated with being anarchistic. Yet, no significant costs have yet been identified.
A possible reason for this may be that researchers have only focused on the behaviour of anarchistic workers, which have been
shown to perform worker-tasks as do wild-type workers. Possibly, therefore, costs associated with anarchy should be sought
in anarchistic queens and not workers. A potential cost could be a lower survival rate of eggs laid by anarchistic queens
perhaps because their egg-marking signal is not as clear as that of a wild-type queen. In this paper, we determined the removal
rate of eggs laid by anarchistic queens in standard worker-policing bioassays. Our results show that eggs laid by anarchistic
queens are removed at a higher rate than eggs laid by wild-type queens. This does not seem to be due to differences in hydrocarbons
found on the surface of eggs, as both egg types showed the same alkanes and alkenes in similar proportions. We postulate that
higher removal rates of queen-laid eggs due to recognition errors may be one reason that anarchy is rare in natural honeybee
populations. 相似文献
Conventional mathematical programming methods, such as linear programming, non linear programming, dynamic programming and
integer programming have been used to solve the cost optimization problem for regional wastewater treatment systems. In this
study, a river water quality management model was developed through the integration of a genetic algorithm (GA). This model
was applied to a river system contaminated by three determined discharge sources to achieve the water quality goals and wastewater
treatment cost optimization in the river basin. The genetic algorithm solution, described the treatment plant efficiency,
such that the cost of wastewater treatment for the entire river basin is minimized while the water quality constraints in
each reach are satisfied. This study showed that genetic algorithm can be applied for river water quality modeling studies
as an alternative to the present methods. 相似文献
The morphogenesis of ephyrae of Atorella vanhoeffeni Bigelow, 1909 (Werner, 1967) and of Nausithoe maculata Jarms, 1990 during strobilation is described. We found differences in the developmental pattern of marginal structures and structural
changes of longitudinal muscle tubes in particular. During strobilation the polyp’s tetraradiate symmetry is passed to the
ephyra of both taxa as a tetraradiate central symmetry that we consider a major plesiomorphic character. The present results
also indicate divergent patterns of ephyra development during strobilation that lead to variable marginal symmetries of ephyrae
and thus of medusae. Therefore, the marginal symmetry of medusae of N. maculata is octoradiate and of A. vanhoeffeni is hexaradiate. We conclude the latter is stated as derived pattern. These results lead us to maintain both families Nausithoidae
and Atorellidae. 相似文献