Population mobility and indigenous peoples: the view from Australia

"This paper describes an emerging field of demographic enquiry focused on the population mobility of indigenous minorities in Australasia and North America. Political, scientific and policy rationales for research on the spatial dynamics of such groups are advanced as a prelude to a review of the Australian literature. This review is structured around four complementary perspectives on mobility: the propensity to move; spatial redistribution; flows and networks; and migration careers. Comparison of the relative strengths of mobility research on the indigenous and non-indigenous populations against these four perspectives assists in identifying outstanding research needs and priorities. Commonalities in the patterns and processes of indigenous mobility in Australia, New Zealand, Canada and the U.S. suggest the value of more detailed cross-national comparisons, and also provide a basis for contemplating an indigenous variant of Zelinsky's hypothesised mobility transition."     

Food habits of red drum and spotted seatrout in a restored mangrove impoundment

Benthic resource utilization by, red drum (Sciaenops ocellatus) and spotted seatrout (Cynoscion nebulosus) was studied in a restored, mangrove-rimmed impoundment (Cabbagehead Bayou) of Upper Tampa Bay, Florida, and in a nearby, natural site of unaltered tidal regime (Double Branch Bay). Diets of fish captured from August 1990 to May 1992 were determined from stomach content analysis. Simultaneously, food availability was evaluated by sampling benthic macroinvertebrates, mobile decapods, and small fish. Red drum and spotted seatrout utilized the restored habitat 1 yr after it was opened to tidal influence. Both species also were collected in the natural mangrove. Although there were noted differences in benthic assemblages between the two sites, red drum and spotted seatrout exhibited flexibility in diet, feeding on abundant and accessible prey. The high abundance of microcrustacea, such as amphipods, on detritus accumulated in the restored habitat constituted a main food resource for both fish species. Major food items in the diet of small (<200 mm) red drum were amphipods, mysids, and nereid and arenicolid polychaetes. Large (200–590 mm) red drum fed on polychaetes, xanthid crabs, palaemonid shrimp, and small fishes. Spotted seatrout preyed primarily upon mysids, shrimp, and small fishes, and to a lesser extent, upon a nereid polychaete. Our findings on fish feeding in a restored mangrove impoundment indicated that the detrital-associated benthic community is utilized by reinvading fish within a short time period, suggesting that not only habitat but food resources were augmented by the reopening of this wetland.     

Magnetic field estimation in Cyg X-3's jet

Multi-wavelength photometric observations of Cygnus X-3 were carried out at 18 cm through to 450 μm, complemented by X-ray (2–10 keV) observations. The system was mildly active with cm fluxes at 150–250 mJy. We find the spectrum to be flat with a spectral index of zero. Using a modified Wolf-Rayet wind model, and assuming emission is generated in synchrotron emitting jets from the source, we find an upper-limit to the magnetic field of 20 G at a distance 5×10¹² cm is required.     

The 3s 2S–4p 2Po transition probability in Mg ii

The superposition of configurations (SOC) method has been used to calculate f -values for the Mg  ii doublet at 1240 Å, which has been observed in the interstellar medium near stars such as ζ Ophiuchi. Our best value for the multiplet oscillator strength is 0.00083. SOC calculations have also been undertaken for the stronger (3s−3p) doublet at 2800 Å giving a multiplet f -value of 0.92.     

The prediction of frost penetration

The effectiveness of the heat balance integral approach in determining the extent of frost penetration of the ground is illustrated.     

An empirical assessment and illustration of some multivariate morphometric techniques

An artificial data set is used to illustrate the morphologic properties of some common multivariate techniques and consideration of three common situations. The first concerns a sample showing no obvious groupings. In this situation principal components (or coordinates) and factor analyses give a logical ordination of form variation; cluster analysis produces sizedominated groups. The second situation considers an homogeneous sample where size and shape have important implications. Principal components are tested for association with size and shape, both of which can be isolated if isometry exists; if allometry is present, isolation of shape is possible only by size elimination, e.g., conversion to ratios. The third situation examines a sample of unknown groupings in which shape variation is the only interest. Aside from ratios, two other methods which produce shape-dominant clusters are assessed. Some of the options available in cluster analysis are also examined.     

A comparison of the levels of hepatic aryl hydrocarbon hydroxylase in fish caught close to and distant from north sea oil fields

Large-scale use of oil-based muds for drilling operations offshore can lead to high concentrations of aromatic hydrocarbons in the sediments close to these platforms. Fish were trawled from stations close to and distant from such platforms and the levels of hepatic aryl hydrocarbon hydroxylase (AHH) were determined in cod, haddock and whiting. These three species were caught in sufficient numbers to make reasonable preliminary data sets. The data for cod and haddock showed significantly higher levels of AHH in the livers of fish caught close to oil platforms than in those caught in areas away from oil activity, while whiting showed no such differences. A much larger sample number together with some measurement of enhanced cytochrome P-450 levels would be required to substantiate this trend, but these data are the first indications that the oil in the sediments around platforms may be biochemically available to fish in the area.     

Évolution des indices des extrêmes climatiques en République du Tchad de 1960 à 2008

[Translated by the editorial staff] An analysis of climate trends and return levels for the period 1960–2008, using the ETCCDI-CLIVAR/JCOMM project approach, has been conducted for Chad, where droughts and flooding are recurrent. Using the RClimDex software, we show that almost all rainfall trends are decreasing, as in Central and Northern Africa. Rare extreme rain events (R99p) decrease significantly: 0.85?mm per decade. However, we note a slightly upward trend of 0.5 day per decade, in the number of consecutive dry days (CDD). Temperature indices are all positive except for the frequencies of very hot days (TX90p) and very cold nights (TN10p), which decrease significantly: ?0.39% day per year per decade, as in Central Africa and globally. Sequences of hot or cold days decrease as well, but by about 1% per year per decade. Return periods identified with the generalized extreme value (GEV) distributions show that they are well defined from 1 to 10 years. Extremely rare events from 10 to 50 years are associated with a mean return level of 660?mm of annual precipitation.