Engineer Cantonment, Missouri Territory, 1819-1820: America\u27s First Biodiversity Ineventory

It is our thesis that members of the Stephen Long Expedition of 1819-20 completed the first biodiversity inventory undertaken in the United States at their winter quarters, Engineer Cantonment, Missouri Territory, in the modern state of Nebraska. This accomplishment has been overlooked both by biologists and historians, but it should rank among the most significant accomplishments of the expedition. The results of this inventory allow us to evaluate the environmental, faunal, and floral changes along the Missouri River in the intervening nearly 190 years. The historical records form a visual image of a dynamic riverine system in which a highly meandering river flows through a wide valley filled with oxbows, palustrine wetlands, and scattered groves of trees. This system has now been modified to a channelized river with the surrounding wetlands drained and converted to agricultural and municipal purposes. The suppression of prairie fires and the adoption of irrigation practices have promoted the growth of trees and other woody vegetation. The city of Omaha and its suburbs are expanding and encroaching on the site from the south and west. At least three taxa recorded at the site have become extinct-Ectopistes migratorius (passenger pigeon), Conuropsis carolinensis (Carolina parakeet), and Canis lupus nubilus (plains subspecies of the gray wolf)-and several more have been extirpated from the region. For mammals, the data indicate that nine species of the 1819-20 fauna have been lost, and two species have been added, thus resulting in a net loss of seven species. These changes represent a net loss of 15% of the mammalian biodiversity originally present in the Engineer Cantonment area. The species richness estimator for Engineer Cantonment in 1819-20 is 403 for vertebrates, insects, snails, and plants, but it is clear that this number is extremely low, because plants were not thoroughly surveyed by the expedition and only a small fraction of the insects were collected

Engineer Cantonment, Missouri Territory, 1819-1820: America\u27s First Biodiversity Ineventory

It is our thesis that members of the Stephen Long Expedition of 1819-20 completed the first biodiversity inventory undertaken in the United States at their winter quarters, Engineer Cantonment, Missouri Territory, in the modern state of Nebraska. This accomplishment has been overlooked both by biologists and historians, but it should rank among the most significant accomplishments of the expedition. The results of this inventory allow us to evaluate the environmental, faunal, and floral changes along the Missouri River in the intervening nearly 190 years. The historical records form a visual image of a dynamic riverine system in which a highly meandering river flows through a wide valley filled with oxbows, palustrine wetlands, and scattered groves of trees. This system has now been modified to a channelized river with the surrounding wetlands drained and converted to agricultural and municipal purposes. The suppression of prairie fires and the adoption of irrigation practices have promoted the growth of trees and other woody vegetation. The city of Omaha and its suburbs are expanding and encroaching on the site from the south and west. At least three taxa recorded at the site have become extinct-Ectopistes migratorius (passenger pigeon), Conuropsis carolinensis (Carolina parakeet), and Canis lupus nubilus (plains subspecies of the gray wolf)-and several more have been extirpated from the region. For mammals, the data indicate that nine species of the 1819-20 fauna have been lost, and two species have been added, thus resulting in a net loss of seven species. These changes represent a net loss of 15% of the mammalian biodiversity originally present in the Engineer Cantonment area. The species richness estimator for Engineer Cantonment in 1819-20 is 403 for vertebrates, insects, snails, and plants, but it is clear that this number is extremely low, because plants were not thoroughly surveyed by the expedition and only a small fraction of the insects were collected

Wave-particle interactions in non-uniform plasma and the interpretation of Hard X-ray spectra in solar flares

Context. High energy electrons accelerated during solar flare are abundant in the solar corona and in the interplanetary space. Commonly, the number and the energy of non-thermal electrons at the Sun is estimated using hard X-ray (HXR) spectral observations (e.g. RHESSI) and a single-particle collisional approximation. Aims. To investigate the role of the spectrally evolving Langmuir turbulence on the population of energetic electrons in the solar corona. Methods. We numerically simulate the relaxation of a power-law non-thermal electron population in a collisional inhomogeneous plasma including wave-particle, and wave-wave interactions. Results. The numerical simulations show that the long-time evolution of electron population above 20 keV deviates substantially from the collisional approximation when wave-particle interactions in non-uniform plasma are taken into account. The evolution of Langmuir wave spectrum towards smaller wavenumbers, due to large-scale density fluctuations and wave-wave interactions, leads to an effective acceleration of electrons. Furthermore, the time-integrated spectrum of non-thermal electrons, which is normally observed with HXR above 20 keV, is noticeably increased due to acceleration of non-thermal electrons by Langmuir waves. Conclusions. The results show that the observed HXR spectrum, when interpreted in terms of collisional relaxation, can lead to an overestimated number and energy of energetic electrons accelerated in the corona.Comment: 8 pages, 6 figures, submitted to Astronomy and Astrophysics Journa

‘Ethnic group’, the state and the politics of representation

The assertion, even if only by implication, that ‘ethnic group’ categories represent ‘real’ tangible entities, indeed identities, is commonplace not only in the realms of political and policy discourse but also amongst contemporary social scientists. This paper, following Brubaker (2002), questions this position in a number of key respects: of these three issues will dominate the discussion that follows. First, there is an interrogation of the proposition that those to whom the categories/labels refer constitute sociologically meaningful ‘groups’ as distinct from (mere) human collectivities. Secondly, there is the question of how these categories emerge, i.e. exactly what series of events, negotiations and contestations lie behind their construction and social acceptance. Thirdly, and as a corollary to the latter point, we explore the process of reification that leads to these categories being seen to represent ‘real things in the world’ (ibid.)

Targeting the Most Harmful Offenders for an English Police Agency: Continuity and Change of Membership in the “Felonious Few”

Funder: University of CambridgeAbstract Research Question How concentrated is the total harm of offences with detected offenders (identified suspects) among the complete list of all detected offenders in a given year in an English police agency, and how consistent is the list of highest-harm “felonious few” offenders from one year to the next? Data Characteristics of 327,566 crimes and 39,545 unique offenders as recorded by Northamptonshire Police in 7 years from 2010 to 2016 provide the basis for this analysis. Methods Crime and offender records were matched to harm weightings derived from the Cambridge Crime Harm Index (Sherman et al. 2016a; Sherman et al., Policing, 10(3), 171–183, 2016b). Descriptive statistics summarize a concentration of harm identifying the felonious few, changes over time in membership of the “few”, offender typologies and tests for escalation of severity, frequency and intermittency across repeated offences. Findings Crime harm is much more concentrated among offenders than crime volume: 80% of crime harm that is identified to an offender is linked to a felonious few of just 7% of all detected offenders. While chronic repeat offenders are the majority contributors to harm totals of this group, those with the most general range of offence types contribute the most harm. Individual members of the felonious few rarely maintain that position year on year; over 95% of each year’s list is composed of individuals not present in previous years. Within individual crime histories, we observe a pattern of de-escalation in crime harm per offence over time. “One-time” offenders, those with just one crime record, typically made up a third of the felonious few in both number and harm contribution. Conclusions These findings demonstrate the potential to target a small number of repeat offenders for harm reduction strategies using a metric of total crime severity, not just volume, despite a substantial portion of crime harm caused by one-time offenders that may be largely unpredictable. </jats:sec

Increased plasma viscosity as a reason for inappropriate erythropoietin formation

The aim of this study was to examine whether altered plasma viscosity could contribute to the inappropriately low production rate of erythropoietin (EPO) observed in patients suffering from hypergammaglobulinemias associated with multiple myeloma or Waldenström's disease. We found that the EPO formation in response to anemia in these patients was inversely related to plasma viscosity. A similar inverse relationship between plasma viscosity and EPO production was seen in rats in which EPO formation had been stimulated by exchange transfusion and the plasma viscosity of which was thereby altered by using exchange solutions of different composition to alter plasma viscosity and thus whole blood viscosity independently from hematocrit. Raising the gammaglobulin concentration to approximately 40 mg/ml plasma in the rats almost totally blunted the rise in serum EPO levels despite a fall of the hematocrit to 20%. Determination of renal EPO mRNA levels by RNase protection revealed that the reductions in serum EPO levels at higher plasma viscosities were paralleled by reductions in renal EPO mRNA levels. Taken together, our findings suggest that plasma viscosity may be a significant inhibitory modulator of anemia-induced EPO formation. The increased plasma viscosity in patients with hypergammaglobulinemias may therefore contribute to the inappropriate EPO production, which is a major reason for the anemia developing in these patients

Shaft whirling in a twin-spool jet engine system

Modern jet engines have two co-axial shafts which rotate usually in the same direction but are not coupled mechanically. In common with other types of high speed machinery, shaft vibration, particularly that excited by unbalance and known as whirling, is a serious problem. Despite the enormous investment involved in the design and development of a new type of jet engine, relatively little research has been done on shaft whirling in jet engines. It is believed that no detailed investigation of whirling in a two shaft system has been carried out. The work described in this thesis was designed to establish the accuracy with which the whirling frequencies could be predicted and in particular to examine how these were influenced by the speeds of the two shafts as a result of gyroscopic effects. The experimental rig constructed for this investigation was a simple full size model of the rear half of a typical twin-spool jet engine. After extensive testing of the components of the rig, a computer model was developed which would predict the natural frequencies of the rig to an accuracy of better than 5%. It was concluded that this accuracy was not likely to be approached in the prediction of the frequencies of an actual jet engine and such calculations should not be relied on in the design of an engine to ensure that whirling did not occur within the working speed range. The computer model was used to explore the variations of the frequencies over a wide range of combinations of shaft speed. Under certain conditions the frequencies were found to be influenced greatly by the speed of one or both shafts. At certain combinations of shaft speed the character of the mode of vibration of the two shafts was changed drastically by relatively small variations in the shaft speeds. Methods of determining the critical points of vibration in the working range of a typical jet engine were examined. It was found that each frequency which lay within the working range was liable to be excited by the unbalance of either shaft. The results suggest that more critical points Of vibration are likely to be encountered in the working range of an engine in which the shafts rotate in opposite directions. In the course of the investigation a careful examination of reverse whirl, in which the bent form of the shaft rotates in the opposite direction to the shaft rotation, was conducted. A plausible explanation of the cause of this phenomenon is given which suggests that it deserves further study. One of the shafts exhibited a severe vibration which was unaffected by the unbalance of the shaft. The mode of vibration was that of a subharmonic and further examination suggested that it was caused by non-linearity of the support of the shaft as a result of bearing clearance. It would appear essential that research into the control of this type of vibration is conducted