Distribution

Changes in the status and distribution of Wisconsin's double-crested cormorant (DCCO) breeding population during the 20th century closely approximate a similar pattern throughout the Great Lakes and generally along the Atlantic coast: a gradual increase in popula- tion size from about 1921 until about 1950, followed by a population crash, and then a remarkable population resurgence beginning in the early

Summary For myxomycetes the understanding of their diversity and of their ecological function remains underdeveloped. Various problems in recording myxomycetes and analysis of their diversity are discussed by the examples taken from tundra, boreal, and arid areas of Russia and Kazakhstan. Recent advances in inventory of some regions of these areas are summarised. A rapid technique of moist chamber cultures can be used to obtain quantitative estimates of myxomycete species diversity and species abundance. Substrate sampling and species isolation by the moist chamber technique are indispensable for myxomycete inventory, measurement of species richness, and species abundance. General principles for the analysis of myxomycete diversity are discussed.

During 2 years (2001–2003), we performed seasonal aerial surveys in the central Spanish Mediterranean following the transect line methodology in order to determine the abundance and distribution patterns of loggerhead turtles Caretta caretta. We surveyed a total of 16 700 km, accounting for 770 turtle sightings. Loggerhead turtles were present with high abundance all year round. No seasonal differences in abundance were found, except in spring 2001, where the density of turtles was higher than in the other seasons. Our results show that the Western Mediterranean is not a ‘summer’ feeding area as proposed previously, as a high number of turtles are present throughout the year. The average surface density of turtles in the whole study area was 0.21 turtles km−2 [95% confidence interval (CI): 0.17–0.25], and the mean abundance was 6653 turtles (95% CI: 5514–8027). The data relate to the number of turtles on the surface only, as diving turtles escape observation. Correcting our estimations of diving behaviour data in the area, the absolute abundance was 18 954 turtles (95% CI: 6679–53 786). Bearing in mind that around 25 000 loggerheads are caught per year in the Spanish Mediterranean, our results indicate that accidental captures seem to be a significant threat for this species, and conservation measures have to be implemented to avoid a non-sustainable situation.

The relation between the Faustmann model and “a forestry of prices” as a concept of thought was examined. At first, the meaning of the Faustmann model in economic sciences is the explanation of allocation and distribution by prices. The rotation age determination plays a secondary role only. Secondly, “a forestry of prices” as an application of the “free to choose” way of thinking is explained. The concept allows us to understand how individuals of anonymous groups achieve forest sustainability and provide forest environmental goods. Thirdly, the relation between the Faustmann model and “a forestry of prices” is discussed. For this purpose, the Faustmann model is described as a scientific laboratory. It helps us to observe how equilibrium arises as a non-intended result of individual welfare maximization in anonymous interactions. And conversely with the help of “a forestry of prices”, we understand also that the individual maximization approach of the Faustmann model re-enacts the unintended interaction situations in anonymous group. With help of the Faustmann model, we can understand deep aspects of “a forestry of prices”. Vice versa, “a forestry of prices” shows the meaning of the formal solutions of the Faustmann model.

Fish and environmental variables were sampled in a mangrove area from Sepetiba bay to assess the role of this system in life cycle of the silverside Atherinella brasiliensis (Quoy & Gaimard, 1824). Standardized monthly sampling using beach seines were conducted at five sites, between August, 2002 and July, 2003 in daily (day/night) basis, with environmental variables being taken at each site. The highest numerical abundance was recorded in the intermediate sample area in the mangrove channel and the lowest in the innermost site. The highest weight occurred in the outermost site near to the sea connection. Numerical abundance was directly correlated with temperature and salinity, and weight with salinity and dissolved oxygen (p < 0.05). Size ranged from 10 to 160 mm TL, with modes of 40-50 mm TL occurring all over the year in all sites. Recruitment occurred all year round but peaks (TL = 30 mm) in October-December, 2002 and July, 2003 were recorded afterwards the records of larger fishes (September, 2002 and June, 2003) mainly in the outermost site. The largest fishes concentrated in the sandy substrate of the outermost sites, areas more suitable for A. brasiliensis spawning, with recruits dispersing all over the mangrove areas, which are used as rearing grounds. The affinity for highly structured habitats in mangrove and the capacity to use efficiently semi-closed systems was confirmed for A. brasiliensis in Guaratiba mangrove.

The Antillean manatee (Trichechus manatus manatus) is considered endangered in Mexico. Local extinctions have been documented in the northern Gulf of Mexico, and the only remaining population with a northern distribution is found in the Alvarado Lagoon System (ALS). The objective of this study was to determine manatee distribution in ALS. The system covers an area of 267,010 ha and includes hundreds of lagoons, floodable areas, and dozens of rivers. To detect manatees, systematic line transects were done in a boat 7.6 m in length, totaling 332.6 h of search effort with an average of 7.38 h d–1 in 45 surveys. There was a total of 13 manatee sightings: seven direct sightings, five with hydrophones, and one with a side-scan sonar. For each record the geographical coordinates were taken and integrated in a geographical information system to analyze their distribution. Manatee distribution was not uniform throughout the study area. Manatees were sighted in very specific areas of ALS cons...

Both insulin resistance (IR) and decreased insulin secretion have been shown to predict the development of NIDDM. However, methods to assess insulin sensitivity and secretion are complicated and expensive to apply in epidemiological studies. The homeostasis model assessment (HOMA) has been suggested as a method to assess IR and secretion from the fasting glucose and insulin concentrations. We applied the HOMA model in the 3.5-year follow-up of the Mexico City Diabetes Study. Out of 1,449 subjects, 97 developed diabetes. When modeled separately insulin resistance but not insulin secretion predicted NIDDM. However, when both variables were entered into the same regression model, both increased IR and decreased beta-cell function significantly predicted NIDDM. We conclude that the HOMA provides a useful model to assess beta-cell function in epidemiological studies and that it is important to take into account the degree of IR in assessing insulin secretion.

Ana Silvaa,b, Laura Quintanaa, Matıas Galeanoa & Pablo Errandoneaa aDepartamento de Neurofisiologıa, Instituto de Investigaciones Biológicas Clemente Estable; Unidad Asociada de Facultad de Ciencias, Universidad de la República, Avda. Italia 3318, 11600 ...

Magnesium is involved in numerous processes that affect muscle function including oxygen uptake, energy production and electrolyte balance. Thus, the relationship between magnesium status and exercise has received significant research attention. This research has shown that exercise induces a redistribution of magnesium in the body to accommodate metabolic needs. There is evidence that marginal magnesium deficiency impairs exercise performance and amplifies the negative consequences of strenuous exercise (e.g., oxidative stress). Strenuous exercise apparently increases urinary and sweat losses that may increase magnesium requirements by 10-20%. Based on dietary surveys and recent human experiments, a magnesium intake less than 260 mg/day for male and 220 mg/day for female athletes may result in a magnesium-deficient status. Recent surveys also indicate that a significant number of individuals routinely have magnesium intakes that may result in a deficient status. Athletes participat...