INFORMATION SOURCES FOR NINETEENTH CENTURY MIDWESTERN MIGRATION*

A variety of sources provides different levels of information about the origins of nineteenth century migrants to the Midwest. The advantages and disadvantages of four of the most common records, the federal census, land office records, genealogical collections, and county histories/biographies/atlases, are examined. Characteristics considered are the specific types of data provided, extent of coverage, level of detail, statistical reliability, and accessibility. Examples of studies using each record type are cited.     

Canonical planetary perturbation equations for velocity-dependent forces,and the Lense-Thirring precession

A form of planetary perturbation theory based on canonical equations of motion, rather than on the use of osculating orbital elements, is developed and applied to several problems of interest. It is proved that, with appropriately selected initial conditions on the orbital elements, the two forms of perturbation theory give rise to identical predictions for the observable coordinates and velocities, while the orbital elements themselves may be strikingly different. Differences between the canonical form of perturbation theory and the classical Lagrange planetary perturbation equations are discussed. The canonical form of perturbation theory in some cases has advantages when the perturbing forces are velocity-dependent, but the two forms of perturbation theory are equivalent if the perturbing forces are dependent only on position and not on velocity. The canonical form of the planetary perturbation equations are derived and applied to the Lense Thirring precession of a test body in a Keplerian orbit around a rotating mass source.     

Speleothem stable isotope records interpreted within a multi-proxy framework and implications for New Zealand palaeoclimate reconstruction

A primary step in the interpretation of speleothem stable isotope records (¹⁸O/¹⁶O and ¹³C/¹²C) is to conduct a comparison with other local palaeoclimate proxies. Here, two new master speleothem δ¹⁸O and δ¹³C records (one from eastern North Island, and the other from western/southern South Island, New Zealand) are evaluated against independent precipitation and temperature proxy information to assess their palaeoclimate reconstruction potential. This comparison also resulted in a serendipitous opportunity to reconstruct past circulation using climate regime classification [Lorrey, A.M., Fowler, A.M., Salinger, J., 2007a. Regional climate regime classification as a qualitative tool for interpreting multi-proxy palaeoclimate data spatial patterns: a New Zealand case study. Palaeo-3, in press], specifically because these two regional climate districts are hyper-sensitive to westerly circulation changes, and in many cases, exhibit contrasting climate character in response to circulation anomalies.For both the western South Island and the eastern North Island master speleothem δ¹³C records, variations tracked changes in relative regional precipitation. The δ¹⁸O master speleothem record for both regions varied with temperature change. Both records contain strong regional climate signals that suggest they have good value for palaeoclimate reconstruction. The ensuing attempt at a multi-proxy reconstruction of regional climate regimes from the compiled proxies indicates past circulation in the New Zealand sector has varied considerably during the past four millennia. Centennial-scale circulation changes for the past 4000 years are evident, and are analogous to modern Blocking, Zonal and Trough regime types [Kidson J. W., 2000. An analysis of New Zealand synoptic types and their use in defining weather regimes. International Journal of Climatology 20, 299–316] that characterise changes in present-day (prevailing) westerly circulation. This palaeoclimate reconstruction indicates modern regional climate regime classification can be extended at least as far back as the temporal coverage of the records presented here, and it can likely be improved on with better dating control and the addition of new records with higher resolution. It is also anticipated that future work will expand to include more proxy data from across New Zealand to improve the clarity of past climate regime occurrence for the Late Holocene.     

Effect of divalent cations on the kinetics of Fe(III) complexation by organic ligands in natural waters

We have investigated the kinetics of Fe(III) complexation by several organic ligands including fulvic acid, citrate and ethylenediaminetetraacetic acid (EDTA). Particular attention was given to examination of the effect of competitive divalent cations (Me: Ca²⁺ and Mg²⁺) at concentrations typical of seawater on the complexation rate. All experiments were conducted in 0.5 M NaCl solution buffered with 2 mM bicarbonate at pH 8.0 in the absence and presence of Me (25 μM-250 mM). The rate constants of complex formation determined by using the competitive ligand (5-sulfosalicylic acid) method combined with visible spectrophotometry ranged from 3.3 × 10⁴ to 3.2 × 10⁶ M⁻¹ s⁻¹. The mechanism of complexation was then examined based on a kinetic model. When EDTA was used as a ligand, Me at concentrations comparable to the ligand markedly retarded the rate of iron complex formation due to the predominance of an adjunctive pathway (where iron-ligand complex is formed via direct association of iron to Me-ligand complex). In contrast, the competing effect of Me on iron complexation by citrate and fulvic acid was observed only when the Me concentration was in excess of the ligand by more than a factor of 10-1000. The kinetic model suggests that iron complexation by fulvic acid occurs predominantly via a disjunctive pathway (where iron complexation by ligand occurs after dissociation of Me from Me-ligand complex) at concentrations of divalent cations and natural organic matter typical of natural waters including seawater and freshwater.     

Subglacial comminution in the deforming bed: Inferences from SEM analysis

This study investigates the variations in erosional processes beneath Briksdalsbreen; a Norwegian valley glacier, with a thin coarse grained deforming bed. The subglacial zone was investigated in situ, close to the central glacial flow line (Site A) and close to the valley wall (Site B), via boreholes. The till was collected using two different sediment samplers and the bed was examined using a borehole video camera. In order to evaluate how representative borehole sampling was of the subglacial environment, the results from in situ subglacial samples were compared with random samples taken from an exposed subglacial surface in the glacier foreland, as well as a sample taken from the site after glacier retreat. The results indicated that the texture of the exposed subglacial surface was similar to in situ samples from subglacial Site B (close to the valley wall), and that the samples collected with the ‘small’ sediment sampler had the closest fit. SEM analysis revealed eroded quartz grains at both sites as a result of rotation (abrasion) and fracture. The samples from close to the valley wall were very poorly sorted, with evidence for rounding and preservation of pre-weathered surfaces, which suggest that a relatively simple pattern of erosion from crushing to rotation dominated. However, the till from the centre of the glacier was better sorted, more angular, and with few pre-weathered surfaces. We suggest that this results from a more complex glacial erosional history associated with greater strain and longer residence time within the deforming layer. When compared with other deformation tills, it was confirmed that there is a relationship between grain size and erosional style. Clay-rich tills show little comminution, fine sand-rich tills generate a significant silt component, whilst the coarse sand-rich tills at Briksdalsbreen showed complex deformational styles but no significant silt component.     

Analysis of an estuarine striped bass population: Effects of environmental conditions during early life

Estuarine fish populations are exposed to a variety of environmental conditions that cause both short-term variability and long-term trends in abundance. We analyzed an extensive data set for striped bass (Morone saxatilis) in the San Francisco Estuary to refine our understanding of how environmental variability influences recruitment. We examined the effects of environmental variability during early life stages on subsequent recruitment (age 3 yr), and the degree to which conditions in early life may have contributed to a long-term decline in abundance of adult striped bass in the San Francisco Estuary. Survival from egg to young-of-the-year varied strongly with freshwater flow; this effect apparently occurred within the first week or two of life, a time period that encompasses transport of eggs and larvae from the rivers to rearing areas and the onset of feeding. The rate of freshwater flow to pumping facilities that export freshwater from the system had small or sporadic effects on survival during the first month or two of life. Although many young striped bass between ages 2 and 8 mo were entrained in export pumping facilities, the resulting high mortality was unrelated to total mortality rates determined from field data on young striped bass. This lack of effect was apparently due to strong density-dependent mortality occurring between ages 1 mo and 3 yr (Kimmerer et al. 2000). The available data do not support previously suggested relationships between recruitment and freshwater flow during early life, or between gross estimates of pesticide input and survival of early life stages. We used a simple life-cycle model to show that various combined factors could have led to a decline in adult abundance, particularly a large and increasing adult mortality, but that events early in life probably did not contribute substantially to the decline. These results demonstrate that several decades of monitoring data from numerous life stages are needed to distinguish among alternative hypotheses about environmental influences on populations of estuarine fish.     

Inversion of sonic waveforms with unknown source and receiver functions

A seismogram that is several times the length of the source-receiver wavelet is windowed into two parts—these may overlap—to obtain two seismograms with approximately the same source function but different Green's functions. A similarly windowed synthetic seismogram gives two corresponding synthetic seismograms. The spectral product of the window 1 data with the window 2 synthetic is equal to the spectral product of the window 1 synthetic with the window 2 data only if the correct earth model is used to compute the synthetic. This partition principle is applied to well-log sonic waveform data from Ocean Drilling Project hole 806B, a slow formation, and used there to estimate Poisson's ratio from a single seismogram whose transmitter and receiver functions are unknown. A multichannel extension of the algorithm gives even better results. The effective borehole radius R _b, was included in the inversion procedure, because of waveform sensitivity to R _b. Inversion results for R _b agreed with the sonic caliper, but not the mechanical caliper; thus if R _b is not included in the inversion its value should be taken from the sonic caliper.     

Mobility of rare-earth elements and copper during shear-zone-related retrograde metamorphism

In Mid Proterozoic crystalline rocks of the Mount Isa Inlier, around Cloncurry, Australia, 2000 km² of alteration and brecciation are the product of high-temperature (> 450 °C) concentrated saline solution activity. During retrogression, this fluid was locally responsible for mobility of V, Y, Nb and light rare-earth elements (15 × enrichment). Copper and S were leached during alteration and this may have been a significant source of components in nearby Cu-Au deposits. Similar rare-earth-element behaviour has been observed in the hematite breccias which host Cu-sulfides at the giant Olympic Dam Cu-Au deposit.     

Source Country Differences in the Spatial Distribution of Foreign Direct Investment in the United States

Statistical analysis of foreign direct investment in the United States reveals source country differences in interstate location. We relate these differences to the knowledge foreign investors have of the United States. Regression analysis indicates a significant concentration of foreign investment from individual countries in larger states and in border states. Worldwide investment in the United States does not show these preferences. Investment from Japan and Canada accounted for most of the interstate dispersal of foreign employment in the 1980s.