Soil compaction caused by timber harvesting in central Appalachian hardwood forests

Two commonly used harvesting systems in central Appalachia were examined to determine the amount of soil compaction associated with each harvest type. A manual system of chainsaw and cable skidder, along with a mechanized system consisting of feller-buncher and grapple skidder were monitored in two central Appalachian hardwood forest sites. Examinations of soil bulk density (lbs/ft 3) were made pre-harvest and post-harvest for each harvest unit. Observations were conducted along the skid roads in conjunction to distance from the landing. Sample points were also taken systematically through each harvest site. The physical condition was recorded using a nuclear density probe. Data were analyzed statistically to determine the effect of operational variables on soil impacts. Results indicate that timber harvesting does affect the soil compaction levels in the woods, as well as along skid roads. Soil compaction also varies by different soil moisture level and soil series

The ISCIP Analyst, Volume II, Issue 6

This repository item contains a single issue of The ISCIP Analyst, an analytical review journal published from 1996 to 2010 by the Boston University Institute for the Study of Conflict, Ideology, and Policy

The Scalability of Multicast Communication

Multicast is a communication method which operates on groups of applications. Having multiple instances of an application which are addressed collectively using a unique, multicast address, allows elegant solutions to some of the more intractable problems in distributed programming, such as providing fault tolerance. However, as multicast techniques are applied in areas such as distributed operating systems, where the operating system may span a large number of hosts, or on faster network architectures, where the problems of congestion reduce the effectiveness of the technique, then the scalability of multicast must be addressed if multicast is to gain a wider application. The main scalability issue was considered to be packet loss due to buffer overrun, the most common cause of this buffer overrun being the mismatch in packet arrival rate and packet consumption at the multicast originator, the so-called implosion problem. This issue affects positively acknowledged and transactional protocols. As these two techniques are the most common protocol designs, it was felt that an investigation into the problems of these types of protocol would be most effective. A model for implosion was developed which was simulated in order to investigate the parameters of implosion. A measure of this implosion was derived from the data, this index of implosion allowing the severity of implosion to be described as well as the location of the implosion in the model. This implosion index was derived by dividing the rate at which buffers were occupied by the rate at which packets were generated by the model. The value may then be used to predict the number of buffers required given the number of packets expected. A number of techniques were developed which may be used to offset implosion, either by artificially increasing the inter-packet gap, or by distributing replies so that no one host receives enough packets to cause an implosion. Of these alternatives, the latter offers the most promise, although requiring a large effort to maintain the resulting hierarchical structure in the presence of multiple failures

Mechanism of T-Cell Lymphomagenesis: Transformation of Growth-Factor-Dependent T-Lymphoblastoma Cells to Growth-Factor-Independent T-Lymphoma Cells

In a previous paper we described the induction by x-irradiation or radiation-induced leukemia virus-in-oculation of two classes of lymphoid T-cell neoplasms: The first class, designated T-cell lymphoblastoma (TCLB), consists of growth-factor-dependent eudiploid cells that home to the spleen and give rise to splenic tumors on injection into syngeneic mice; the second class, designated T-cell lymphoma (TCL), consists of growth-factor-independent aneuploid or pseudodiploid cells that give rise to local tumors at the site of subcutaneous injection. This paper describes the generation of a family of growth-factor-independent aneuploid or pseudodiploid TCL cells after the injection into the thymus of growth-factor-dependent diploid TCLB cells. In contrast to the donor TCLB cells, the resulting TCL cells could be cloned in semisolid medium, produced local tumors at the site of subcutaneous injection, and proliferated in a growth-factor-independent fashion in vitro. The induced growth-factor-independent TCL cells were chromosomally and phenotypically unstable and continued to evolve both in vivo and in vitro. After propagation in the thymus, the cells often showed stable translocations in addition to the evolving aneuploidy. We propose that the chromosome abnormalities induced during the proliferation of growth-factor-dependent TCLB cells in the thymus constitute a general mechanism by which neoplastic cells progress from growth-factor dependency to independency

Poverty and Progress in the U.S. South since 1920

Poverty, disease, and illiteracy had long bedeviled the U.S. South, even before the agricultural depression of the 1920s became subsumed within the Great Depression of the 1930s. The essays collected in this volume examine a variety of responses to economic depression and poverty. They recount specific battles for civil, educational, and labor rights, and explore the challenges and alternatives to the corporate South in the post World War II agribusiness era. Scholars from both the U.S. and Europe assess how far the South has come in the last century, what forces (from the Sears Roebuck Catalog to the Civil Rights Movement) have been at work in its transformation, and whether the region\u27s reincarnation as the Sunbelt has lifted the burdens of southern history. Contributors assess labor strikes and demonstrations that have not always found a place in histories of the region and revisit and reassess key southern figures from Erskine Caldwell and James Agee to Albert Gore and Lyndon Johnson. They draw our attention to neglected writers whose representations of poverty deserve more critical attention, and they provide critical analysis of contemporary authors and filmmakers.https://scholarship.richmond.edu/bookshelf/1034/thumbnail.jp

Developing an Advanced Life Support System for the Flexible Path into Deep Space

Long duration human missions beyond low Earth orbit, such as a permanent lunar base, an asteroid rendezvous, or exploring Mars, will use recycling life support systems to preclude supplying large amounts of metabolic consumables. The International Space Station (ISS) life support design provides a historic guiding basis for future systems, but both its system architecture and the subsystem technologies should be reconsidered. Different technologies for the functional subsystems have been investigated and some past alternates appear better for flexible path destinations beyond low Earth orbit. There is a need to develop more capable technologies that provide lower mass, increased closure, and higher reliability. A major objective of redesigning the life support system for the flexible path is achieving the maintainability and ultra-reliability necessary for deep space operations

TimeNotes: A Study on Effective Chart Visualization and Interaction Techniques for Time-Series Data

Collecting sensor data results in large temporal data sets which need to be visualized, analysed, and presented. One dimensional time-series charts are used, but these present problems when screen resolution is small in comparison to the data. This can result in severe over-plotting, giving rise for the requirement to provide effective rendering and methods to allow interaction with the detailed data. Common solutions can be categorized as multi-scale representations, frequency based, and lens based interaction techniques. In this paper, we comparatively evaluate existing methods, such as Stack Zoom [15] and ChronoLenses [39], giving a graphical overview of each and classifying their ability to explore and interact with data. We propose new visualizations and other extensions to the existing approaches. We undertake and report an empirical study and a field study using these techniques

Implementing generalized deep-copy in MPI

In this paper we introduce a framework for implementing deep copy on top of MPI. The process is initiated by passing just the root object of the dynamic data structure. Our framework takes care of all pointer traversal, communication, copying and reconstruction on receiving nodes. The benefit of our approach is that MPI users can deep copy complex dynamic data structures without the need to write bespoke communication or serialize / deserialize methods for each object. These methods can present a challenging implementation problem that can quickly become unwieldy to maintain when working with complex structured data. This paper demonstrates our generic implementation, which encapsulates both approaches. We analyze the approach with a variety of structures (trees, graphs (including complete graphs) and rings) and demonstrate that it performs comparably to hand written implementations, using a vastly simplified programming interface. We make the source code available completely as a convenient header file