Human demographic trends and landscape level forest management in the northwest Wisconsin Pine Barrens

The effects of landscape pattern on forest ecosystems have been a recent focus in forest science. Forest managers are increasingly considering landscape level processes in their management. Natural disturbance patterns provide one baseline for such management. What has been largely ignored is the pattern of human habitation patterns (i.e., housing), on landscapes. The objective of this study is to discuss landscape level management options for the northwest Wisconsin Pine Barrens based on both landscape ecology and the human demographics of the region. Using the 1990 U.S. Decennial Census we examined current housing density, seasonal housing unit concentration, historic housing density change and projected future housing densities. These data were related to land cover and land ownership data using a GIS. Housing density increase was particularly pronounced in the central Pine Barrens, an area where seasonal housing units are common. Lakes and streams were more abundant in areas that exhibited highest growth. Within national forest lands, 80% of the area contained no housing units. In contrast, only 12% of the area in small private land ownership contained no housing. These results are integrated with previous studies of presettlement vegetation and landscape change to discuss landscape level management suggestions for the Pine Barrens

Evolution of arboreality and fossoriality in squirrels and aplodontid rodents: Insights from the semicircular canals of fossil rodents

Reconstructing locomotor behaviour for fossil animals is typically done with postcranial elements. However, for species only known from cranial material, locomotor behaviour is difficult to reconstruct. The semicircular canals (SCCs) in the inner ear provide insight into an animal's locomotor agility. A relationship exists between the size of the SCCs relative to body mass and the jerkiness of an animal's locomotion. Additionally, studies have also demonstrated a relationship between SCC orthogonality and angular head velocity. Here, we employ two metrics for reconstructing locomotor agility, radius of curvature dimensions and SCC orthogonality, in a sample of twelve fossil rodents from the families Ischyromyidae, Sciuridae and Aplodontidae. The method utilizing radius of curvature dimensions provided a reconstruction of fossil rodent locomotor behaviour that is more consistent with previous studies assessing fossil rodent locomotor behaviour compared to the method based on SCC orthogonality. Previous work on ischyromyids suggests that this group displayed a variety of locomotor modes. Members of Paramyinae and Ischyromyinae have relatively smaller SCCs and are reconstructed to be relatively slower compared to members of Reithroparamyinae. Early members of the Sciuroidea clade including the sciurid Cedromus wilsoni and the aplodontid Prosciurus relictus are reconstructed to be more agile than ischyromyids, in the range of extant arboreal squirrels. This reconstruction supports previous inferences that arboreality was likely an ancestral trait for this group. Derived members of Sciuridae and Aplodontidae vary in agility scores. The fossil squirrel Protosciurus cf. rachelae is inferred from postcranial material as arboreal, which is in agreement with its high agility, in the range of extant arboreal squirrels. In contrast, the fossil aplodontid Mesogaulus paniensis has a relatively low agility score, similar to the fossorial Aplodontia rufa, the only living aplodontid rodent. This result is in agreement with its postcranial reconstruction as fossorial and with previous indications that early aplodontids were more arboreal than their burrowing descendants

Study of hybrid Х pinches in different conditions

A standard X-pinch consists of two or more fine wires that cross at a single point as the load of a pulsed power generator. To simplify the X-pinch load, a hybrid configuration consisting of solid conical electrodes connected by a wire, has been suggested and tested on four generators ranging in current from 200 kA to 1 MA and risetimes varying from 45 to 170 ns. The experiments have shown that for each generator, a wire material, diameter and length can be found for which the X-pinches generate a single intense burst of soft x-rays and develop a single hot spot. Also they generated less hard x-ray intensity than that measured in comparable standard X-pinches.Стандартные Х-пинчи состоят из двух или более проволочек, перекрещенных в диоде сильноточного генератора. Чтобы упростить конфигурацию Х-пинчей, была предложена и протестирована на четырех сильноточных генераторах с токами от 200 кА до 1 МА и временем нарастания импульса от 45 до 170 нс нагрузка в виде гибридного Х-пинча. Гибридные Х-пинчи состоят из двух твердотельных тугоплавких электродов, соединенных проволочкой. Проведенные эксперименты показали, что для каждого генератора можно подобрать материал проволочки, диаметр и длину, при которых гибридные Х-пинчи образуют единичную горячую точку и излучают интенсивную вспышку мягкого рентгеновского излучения. При этом зарегистрированный уровень жесткого рентгеновского излучения был значительно ниже, чем в стандартных Х-пинчах.Стандартні Х-пінчі складаються з двох або більше дротиків, перехрещених у діоді потужнострумового генератора. Щоб спростити конфігурацію Х-пінча, була запропонована і протестована на чотирьох потужнострумових генераторах із струмами від 200 кА до 1 МА та часом наростання імпульсу від 45 до 170 нс навантаження у вигляді гібридного Х-пінча. Гібридні Х-пінчі складаються з двох твердотільних тугоплавких електродів, з'єднаних дротиком. Проведені експерименти показали, що для кожного генератора можна підібрати матеріал дротика, діаметр і довжину, при яких гібридні Х-пінчі утворюють одиничну гарячу краплю та випромінюють інтенсивний спалах м'якого рентгенівського випромінювання. При цьому зареєстрований рівень жорсткого рентгенівського випромінювання був значно нижче, ніж у стандартних Х-пінчах