Authigenic kaolinite in the Bear Den Member (Paleocene) of the Golden Valley Formation, in southwestern North Dakota

The Golden Valley Formation of North Dakota crops out in isolated remnants over a large area of southwestern North Dakota. The formation has two members, the lower Bear Den Member, which is characterized by kaolin and bright colors and the upper Camels Butte Member, which is characterized by micaceous sand and clay. Two different theories, either in place weathering or detrital deposition, have developed as to the origin of the kaolinite in the lower member. Early workers suggest that the kaolinite of the member is detrital in origin for the following reasons: 1. No unconformity is present at the top of the Bear Den Member. 2. The unit is too uniform and widespread, and has a stratiform nature that cannot be explained by weathering, 3. Plagioclase, amphibole, pyrite, and siderite are present but would not have been able to withstand weathering. 4. Kaolinite and muscovite show parallel alignment. This study reviews these ideas and more recent work that suggests that the kaolinite of the Bear Den Member was formed in place by weathering. ln addition, analyses made with the scanning electron microscope, microprobe, and X-ray diffractometer give the following evidence that this member has been formed by a weathering process: 1. The mineralogy and mineral profiles are consistent with those of a weathered horizon. 2. Favorable climatic conditions for weathering were present during the Eocene. 3. The topography and thickness relationships of the Bear Den are similar to that of a soil. 4. The kaolinite horizon transgresses Sentinel Butte strata. 5. Scanning electron photomicrographs illustrate a varying degree of crystallinity in the kaolinite. 6. Chemical data show that leaching of the Bear Den sediment has occurred. 7. The Bear Den Member compares favorably with similar units that have been interpreted as weathered horizons. A review of the evidence for and against the theory of weathering indicates that the kaolinite of the Bear Den Member formed in place by weathering processes

Factors affecting velvet antler weights in free-ranging reindeer in Alaska

Free-ranging reindeer on the Seward Peninsula in western Alaska are rounded up from late May to early July and antlers are removed. We used data collected from 1987 to 1997 to determine how velvet antler weights of males and females varied with age, year, reproductive status, Julian date, and body weight. Male antler weights increased with age up to age five years, and were lower in castrates than in bulls. There was a significant positive relationship between body weight and antler weight in both sexes. Female antler weights increased with age until at least age nine. Lactating females had lower antler weights than non-lactating females, but this effect is better explained by differences in body weight. Antler weight of individual reindeer at age two years was better predicted by their antler weights as yearlings than their body weight as yearlings

Lactation in yearling Alaskan reindeer: Implications for growth, reproduction, and survival

Unlike most Rangifer herds, free-ranging female reindeer {Rangifer tarandus) on the Seward Peninsula, Alaska frequently give birth as yearlings (12 months). In other reindeer herds this early reproduction has led to negative effects such as decreased future weight gain and reproduction. We analyzed reindeer data collected on the Seward Peninsula between 1987 and 1997 to determine what effect lactating as yearlings had on future weight gain, reproductive rates, and survival. Reindeer were rounded up during June and early July. Individual ear tag numbers were recorded, females were visually inspected for the presence of a distended udder, and some animals were weighed. Females with distended udders as yearlings had subsequent recapture rates, survival rates, weight gain, and future reproductive success comparable to females that did not have distended udders as yearlings. These findings suggest that the beneficial effects of increased calf weight gain outweigh potential negative effects of early reproduction in these reindeer. This may be due to high quality range leading to heavy calves and the ability of females to maintain body reserves during lactation

Effects of Gas Flaring on the Behavior of Night-migrating Birds at an Artificial Oil-production Island, Arctic Alaska

We studied movement rates and the general flight behavior of bird flocks seen on radar and recorded visually at Northstar Island, Arctic Alaska, from 13 to 27 September 2002. Most of this period (13 – 19 and 21 – 27 September) had no gas-flaring events, but a major gas-flaring event occurred on the night of 20 September. Movement rates of targets on radar and of bird flocks recorded visually in the first ~50% – 60% of the night were much lower during the non-flaring period than during the night of flaring, whereas rates in the last ~40% – 50% of the night were similar in all periods. The general flight behavior of birds also differed significantly, with higher percentages of both radar targets and bird flocks exhibiting straight-line (directional) flight behaviors during the non-flaring periods and higher percentages of radar targets and bird flocks exhibiting non-straight-line (erratic and circling) flight behaviors during the gas-flaring period. During the night of gas flaring, the bright illumination appeared to have an effect only after sunset, when flocks of birds circled the island after being drawn in from what appeared to be a substantial distance from the island. On both radar and visual sampling, the number of bird flocks approaching the island declined over the evening, and the attractiveness of the light from flaring appeared to decline. The visibility of the moon appeared to have little effect on the behavior of birds. Because illumination from extensive gas-flaring is such a strong attractant to migrating birds and because most bird flocks fly at low altitudes over the water, flaring booms on coastal and offshore oil-production platforms in Arctic Alaska should be positioned higher than the mean flight altitudes of migrating birds to reduce the chances of incineration.Nous avons étudié les taux de déplacement et le comportement de vol général des troupeaux d’oiseaux captés par radar ou consignés visuellement à l’île Northstar, dans l’Alaska de l’Arctique, du 13 au 27 septembre 2002. Pendant presque toute cette période (du 13 au 19 et du 21 au 27 septembre), il n’y a pas eu de brûlage de gaz à la torche, mais la nuit du 20 septembre, il y a eu un important brûlage de gaz à la torche. Les taux de déplacement des cibles radar et des troupeaux d’oiseaux consignés visuellement pendant la première tranche d’environ 50 % à 60 % de la nuit étaient beaucoup moins élevés pendant la période où il n’y avait pas de brûlage à la torche que pendant la nuit où il y a eu brûlage à la torche, tandis que pendant la deuxième tranche d’environ 40 % à 50 % de la nuit, les taux de déplacement étaient semblables pendant toutes les périodes. Le comportement de vol général des oiseaux a également affiché une différence considérable. De plus grands pourcentages de cibles radar et de troupeaux d’oiseaux adoptaient un comportement de vol rectiligne (direct) pendant les périodes où il n’y avait pas de brûlage à la torche, et de plus grands pourcentages de cibles radar et de troupeaux d’oiseaux affichaient un comportement de vol non rectiligne (erratique et indirect) pendant la période où il y a eu brûlage à la torche. La nuit du brûlage à la torche, la vive illumination n’a semblé avoir un effet qu’après le coucher du soleil, quand les troupeaux d’oiseaux encerclaient l’île après avoir été attirés depuis un endroit qui semblait très lointain. Tant pour l’échantillonnage prélevé par radar que par consignation visuelle, le nombre de troupeaux d’oiseaux s’approchant de l’île diminuait dans le courant de la soirée, et l’attrait de la lumière émanant du brûlage à la torche semblait également diminuer. La visibilité de la lune semblait avoir peu d’effet sur le comportement des oiseaux. Puisque l’illumination provenant du brûlage prolongé à la torche exerce une si grande force d’attraction chez les oiseaux migrateurs, et puisque la plupart des troupeaux d’oiseaux volent en basse altitude au-dessus de l’eau, le torchage effectué sur les plateformes pétrolières côtières et extracôtières dans l’Alaska de l’Arctique devrait être positionné plus haut que les altitudes moyennes de vol des oiseaux migrateurs afin de réduire les risques d’incinération

On the Induced Flow of an Electrically Conducting Liquid in a Rectangular Duct by Electric and Magnetic Fields of Finite Extent

Reported here are the results of a systematic study of a model of the direct-current electromagnetic pump. Of particular interest is the motion imparted to the electrically conducting fluid in the rectangular duct by the body forces that result from applied electric and magnetic fields. The purpose of the investigation is to associate the observed fluid motion with the characteristics of the electric and magnetic fields which cause them. The experiments were carried out with electromagnetic fields that moved a stream of copper sulphate solution through a clear plastic channel. Ink filaments injected into the stream ahead of the region where the fields were applied identify the motion of the fluid elements as they passed through the test channel. Several magnetic field configurations were employed with a two-dimensional electric current distribution in order to study and identify the magnitude of some of the effects on the fluid motion brought about by nonuniformities in the electromagnetic fields. A theoretical analysis was used to guide and evaluate the identification of the several fluid motions observed. The agreement of the experimental data with the theoretical predictions is satisfactory. It is found that sizable variations in the velocity profile and pressure head of the output stream are produced by the shape of the electric and magnetic fields

Effects of a Hazing-Light System on Migration and Collision Avoidance of Eiders at an Artificial Oil-Production Island, Arctic Alaska

During migration, Common and King Eiders (Somateria mollissima and S. spectabilis) cross the Beaufort and Chukchi Seas of Arctic Alaska. Because they may become attracted to lights, eiders are susceptible to collision with structures, including offshore oil facilities. We used ornithological radar in 2001 – 04 to characterize the behavior of eiders migrating past Northstar Island, an oil-production island near Prudhoe Bay, Alaska, and to assess the effects of a hazing-light system on migrating eiders. “Eider” radar targets exhibited pulsed, irregular periods of movement; movement rates were higher when sea ice was present, without precipitation, and during tailwinds and crosswinds but were not affected by lights. Velocities (ground speeds) were higher when ice was present and with strong tailwinds. They were lower at night when the lights were on, but higher during the day when the lights were on. Radar targets exhibited little variation in flight behavior as they passed the island; the proportion of non-directional behavior was larger when ice was present, with tailwinds, with weak winds, and near the full moon when it was not visible. Lights had no effect on flight behavior. Birds tended to exhibit more course changes as they approached the island, greater angular changes when they changed course, and larger net increases in passing distance as a result of those course changes when the lights were on; however, none of these differences were statistically significant. Overall, the hazing lights at Northstar did not disrupt the birds’ migratory movements but resulted in increased avoidance of the island.En période de migration, l’eider à duvet et l’eider à tête grise (Somateria mollissima et S. spectabilis) survolent la mer de Beaufort et la mer des Tchouktches dans l’Alaska de l’Arctique. Comme ils sont attirés par les lumières, les eiders risquent d’entrer en collision avec des structures, y compris les installations pétrolières au large. De 2001 à 2004, nous avons utilisé un radar ornithologique pour caractériser le comportement des eiders qui migrent au-delà de l’île Northstar, une île de production pétrolière près de Prudhoe Bay, en Alaska, et pour évaluer les effets d’un système d’éclairage de dispersion sur les eiders en migration. Les « eiders » ciblés par le radar présentaient des périodes de mouvement pulsées et irrégulières; les taux de mouvement étaient plus importants en présence de glace marine, en l’absence de précipitation et en présence de vent arrière et de vent latéral, mais n’étaient pas touchés par les lumières. Les vélocités (vitesses au sol) étaient plus élevées en présence de glace et de forts vents arrière. Elles étaient plus basses la nuit lorsque les lumières étaient allumées, mais plus élevées le jour lorsque les lumières étaient allumées. Nous avons observé peu de variation quant au comportement de vol des cibles atteintes par le radar pendant qu’elles survolaient l’île; la proportion de comportements de vol non directionnels était plus importante en présence de glace, de vent arrière, de vent faible et lorsque la pleine lune n’était pas visible. Les lumières n’ont pas eu d’impact sur le comportement de vol. Lorsque les lumières étaient allumées, les oiseaux avaient tendance à changer de direction plus souvent durant leur vol à l’approche de l’île et à effectuer de plus grandes variations angulaires lorsqu’ils changeaient de direction, puis présentaient une nette augmentation de la distance de passage à la suite de ces changements de direction. Toutefois, aucune de ces différences n’était statistiquement importante. En général, les lumières de dispersion de l’île Northstar n’ont pas nui aux mouvements migratoires des oiseaux, mais ces derniers ont davantage évité de voler près de l’île

Taxing the Informal Economy: The Current State of Knowledge and Agendas for Future Research

This paper reviews the literature on taxation of the informal economy, taking stock of key debates and drawing attention to recent innovations. Conventionally, the debate on whether to tax has frequently focused on the limited revenue potential, high cost of collection, and potentially adverse impact on small firms. Recent arguments have increasingly emphasised the more indirect benefits of informal taxation in relation to economic growth, broader tax compliance, and governance. More research is needed, we argue, into the relevant costs and benefits for all, including quasi-voluntary compliance, political and administrative incentives for reform, and citizen-state bargaining over taxation

The structure of and origin of nodular chromite from the Troodos ophiolite, Cyprus, revealed using high-resolution X-ray computed tomography and electron backscatter diffraction

Nodular chromite is a characteristic feature of ophiolitic podiform chromitite and there has been much debate about how it forms. Nodular chromite from the Troodos ophiolite in Cyprus is unusual in that it contains skeletal crystals enclosed within the centres of the nodules and interstitial to them. 3D imaging and electron backscatter diffraction have shown that the skeletal crystals within the nodules are single crystals that are surrounded by a rim of polycrystalline chromite. 3D analysis reveals that the skeletal crystals are partially or completely formed cage or hopper structures elongated along the axis. The rim is composed of a patchwork of chromite grains that are truncated on the outer edge of the rim. The skeletal crystals formed first from a magma supersaturated in chromite and silicate minerals crystallised from melt trapped between the chromite skeletal crystal blades as they grew. The formation of skeletal crystals was followed by a crystallisation event which formed a silicate-poor rim of chromite grains around the skeletal crystals. These crystals show a weak preferred orientation related to the orientation of the core skeletal crystal implying that they formed by nucleation and growth on this core, and did not form by random mechanical aggregation. Patches of equilibrium adcumulate textures within the rim attest to in situ development of such textures. The nodules were subsequently exposed to chromite under-saturated magma resulting in dissolution, recorded by truncated grain boundaries in the rim and a smooth outer surface to the nodule. None of these stages of formation require a turbulent magma. Lastly the nodules impinged on each other causing local deformation at points of contact

The Fire and Smoke Model Evaluation Experiment - A plan for integrated, large fire-atmosphere field campaigns

The Fire and Smoke Model Evaluation Experiment (FASMEE) is designed to collect integrated observations from large wildland fires and provide evaluation datasets for new models and operational systems. Wildland fire, smoke dispersion, and atmospheric chemistry models have become more sophisticated, and next-generation operational models will require evaluation datasets that are coordinated and comprehensive for their evaluation and advancement. Integrated measurements are required, including ground-based observations of fuels and fire behavior, estimates of fire-emitted heat and emissions fluxes, and observations of near-source micrometeorology, plume properties, smoke dispersion, and atmospheric chemistry. To address these requirements the FASMEE campaign design includes a study plan to guide the suite of required measurements in forested sites representative of many prescribed burning programs in the southeastern United States and increasingly common high-intensity fires in the western United States. Here we provide an overview of the proposed experiment and recommendations for key measurements. The FASMEE study provides a template for additional large-scale experimental campaigns to advance fire science and operational fire and smoke models

Measuring Information Transfer

An information theoretic measure is derived that quantifies the statistical coherence between systems evolving in time. The standard time delayed mutual information fails to distinguish information that is actually exchanged from shared information due to common history and input signals. In our new approach, these influences are excluded by appropriate conditioning of transition probabilities. The resulting transfer entropy is able to distinguish driving and responding elements and to detect asymmetry in the coupling of subsystems.Comment: 4 pages, 4 Figures, Revte