Female reciprocal calling in the Iberian midwife toad (Alytes cisternasii) varies with male call rate and dominant frequency: implications for sexual selection

Male midwife toads (Alytes cisternasii) responded differently depending on the call frequency and call rate of other males. I tested female Iberian midwife toads with the same set of stimuli used earlier with males. Females responded faster to high call rates, and female vocal activity was greater in response to low-frequency male calls. Thus, in both sexes, the vocal response differs in the same direction according to signal frequency variation, but the magnitude of the response is greater in males than in females. In the light of these results, I discuss the implications for sexual selection of this reciprocal calling.     

Use of metal-reducing bacteria for bioremediation of soil contaminated with mixed organic and inorganic pollutants

Mixed contamination by organic and inorganic compounds in soil is a serious problem for remediation. Most laboratory studies and field-scale trials focused on individual contaminant in the past. For concurrent bioremediation by biodegradation and bioleaching processes, we tested metal-reducing microorganism, Geobacter metallireducens. In order to prove the feasibility of the coupled process, multiple-contaminated soil was prepared. Mineralogical analyses have shown the existence of labile forms of As(V) as amorphous and/or weakly sorbed phases in the secondary Fe oxides. In the biotic experiment using G. metallireducens, biodegradation of toluene and bioleaching of As by bacteria were observed simultaneously. Bacteria accelerated the degradation rate of toluene with reductive dissolution of Fe and co-dissolution of As. Although there have been many studies showing each individual process, we have shown here that the idea of concurrent microbial reaction is feasible. However, for the practical use as a remediation technology, more details and multilateral evaluations are required in future studies.

     

Land Management Versus Natural Factors in Land Instability: Some Examples in Northern Spain

The objective of this work is to test a hypothesis formulated on the basis of former results which considers that there might be a “global geomorphic change,” due to activities related to land management and not determined by climate change, which could be causing an acceleration of geomorphic processes. Possible relationships between some geomorphic processes related to land instability (landslides or sediment generation) and potential triggering factors are analyzed in study areas in northern Spain. The analysis is based on landslide inventories covering different periods, as well as the determination of sedimentation rates. Temporal landslide and sedimentation rate trends are compared with different indicators of human activities (land-use change, logging, forest fires) and with potential natural triggers (rainfall, seismicity). The possible influence of the road network in the distribution of landslides is also analyzed. Results obtained show that there is a general increase of both landslide and sedimentation rates with time that cannot be explained satisfactorily by observed rainfall trends and even less by seismicity. Land-use change appears to be by far the main factor leading to land instability, with some changes producing up to a 12-fold increase of landslide rate. A relationship between road network and the spatial distribution of landslides has also been observed. These results do confirm the existence of an acceleration of geomorphic processes in the region, and also suggest that climate-related factors play a limited role in the changes observed.     

A low cost instrument based on a solid state sensor for balloon-borne atmospheric O(3) profile sounding

The design of an instrument based on a solid state tungsten oxide sensor for making profile measurements of atmospheric ozone from balloon platforms is described. The sensor is operated at a constant temperature, typically 530 [degree]C. The importance of a detailed consideration of the electronic design is demonstrated, with particular reference to the circuit to control the sensor heater. Calibration methods which are straightforward to implement are illustrated, and the results of a test flight alongside an electrochemical ozonesonde are shown. Quantitative agreement within 25% for most of the profile demonstrates the potential of this type of sensor for ozone sounding. Future improvements from manufacture to analysis are expected to improve on this.     

Dialogic writing as a tool for thinking and learning about the environment

Competence in understanding and resolving environmental problems requires a curriculum that integrates traditional disciplines with applied problem-solving skills and/or methods. Building upon the work of scholars who are calling for curriculum reform so that students may understand better the ethical dimensions of environmental problems, we analyze the theory of using dialogic writing to think and learn about the environment, and we provide examples of application of this technique.     

Bolivia's strategy for restructuring the state's mining sector and promoting private investment in mining

Bolivia is a country of great mineral wealth with known reserves estimated to be worth over US$7 billion. Despite this great potential wealth, in the early 1980s the mining industry of Bolivia found itself in a crisis characterized by excessive state intervention in the industry, a financially troubled state mining company, large areas of the country off-limits to mineral development, an irrational tax system which discouraged mining and labour unrest. To deal with these problems, the government decided to restructure the mining industry so as to encourage private participation. This paper describes the policies introduced to revitalize the mining industry as well as projections of what the future benefits would be to the country if those policies are successful in achieving their objectives.     

Developmental types of shallow-water asteroids of McMurdo Sound,Antarctica

The mode of development was ascertained for 14 of the 16 species of sea stars known to occur in shallow waters of McMurdo Sound, Antarctica (77°51S; 166°40E). The species were collected between September 1984 and December 1985. Females of three species,Odontaster validus, O. meridionalis andPorania antarctica, spawn small to moderate eggs (0.17 to 0.55 mm), have a high fecundity, and produce feeding larvae. Females of an undescribedPorania species spawn a few eggs (150 to 310) that are 0.55 mm in diameter and develop into demersal non-feeding larvae. Females ofDiplasterias brucei andNotasterias armata produce a few (<300) large eggs (2.8 to 3.5 mm) and brood their young. Females of the remaining eight species have moderate fecundity and produce pelagic non-feeding larvae, as determined from egg type (buoyant, 0.54 to 1.28 mm diam) and direct observations of spawning and development. The high incidence (11 out of 14 species; 79%) of non-feeding development is consistent with predictions that environmental conditions in high-latitude regions are unfavorable for planktotrophic development. Nonetheless, most of the species surveyed (11 out of 14) had pelagic larvae, which contradicts inferences of unusual selection for benthic development in the Antarctic.