Population Responses of Microtus pennsylvanicus across a Chronological Sequence of Habitat Alteration

Author Institution: Dept of Biology, Muskingum College, New Concord, OHUnderstanding the effects of habitat alteration on population demography and persistence is emerging as one of the most important and challenging areas facing ecologists and conservation biologists today. Here we compare the population demography of a common but important consumer species in eastern and mid-western grassland communities (Microtus pennsylvanicus) across three habitats that differ in the amount of time since reclamation following strip-mining (30, 25, and 15 years). We established two 40 × 40 m plots at each of the three sites and used traditional capture-recapture techniques to monitor population size, survival, and recruitment through a nine-month period during 1999-2000. We predicted that populations of M. pennsylvanicus would exhibit higher population numbers, better survival rates, and higher rates of recruitment in habitat patches that had been recovering for longer periods of time. In contrast to our predictions, results indicated higher peak population numbers at the most recently disturbed site ( χ = 81.18 ± 9.59 individuals) and higher numbers of reproductive females ( χ = 3.38 ± 0.85) relative to sites recovering for 25 and 30 years ( χ peak population size = 28.08 ± 23.09 and 31.16 ± 1.75 individuals, respectively; χ number of reproductive females = 0.57 ± 0.32 and 1.13 ± 0.13, respectively). Thus it would appear that time since disturbance was not an important predictor of population performance for this species in this altered system. Alternative hypotheses such as the influence of local habitat attributes and population fluctuations are discussed

Impact by North American Beaver (Castor canadensis) on Forest Plant Composition in the Wilds, a Surface-Mined Landscape in Southeastern Ohio

Author Institution: Department of Biology, Muskingum CollegeThe impacts of Castor canadensis Kuhl (American beaver) on local ecosystems through foraging and dam construction activities have been well documented. Here we examined beaver foraging activity in the Wilds, an ecosystem in southeastern Ohio that was most recently subjected to surface mining between the late 1960s and the middle 1980s. Our objective was to make detailed observations of recent and past foraging patterns with the aim of better assessing the impact beaver might have on the recovery of forests in this altered landscape. One active site, a site downstream of the active impoundment and two recently abandoned beaver dam sites were chosen as study sites. At all sites, terrestrial foraging by beaver was generally concentrated within 20 m of water's edge and declined sharply beyond 40 m. Foraging activity was concentrated on, but did not seem to be limiting, the dominant standing species. Thus, there was little indication that foraging activity might be directly altering the nature of forest development in this community. However, other less direct impacts such as consequences arising from damming activities may well yet yield important and long-term effects in this recovering ecosystem

A quantitative comparison of the cost of employing EOR-coupled CCS supplemented with secondary DSF storage for two large CO2 point sources

AbstractThis paper explores the impact of the temporally dynamic demand for CO2 for CCS-coupled EOR by evaluating the variable demand for new (i.e., non-recycled) anthropogenic CO2 within EOR projects and the extent to which EOR-coupled CCS is compatible with the need for baseload CO2 storage options for large anthropogenic point sources. A profile of CO2 demand over an assumed EOR project lifetime is applied across two different storage scenarios to illustrate the differences in cost associated with different EOR-coupled CCS configurations. The first scenario pairs a single EOR field with a DSF used to store any CO2 that is not used to increase oil recovery in the EOR field; the second scenario is designed to minimize storage in the DSF and maximize lower-cost EOR-based storage by bringing multiple EOR projects online over time as the previous project’s CO2 demand declines, making the source’s CO2 available for a subsequent project. Each scenario is evaluated for two facilities, emitting 3 and 6 MtCO2/y. Annual and lifetime average CO2 transport and storage costs are presented, and the impact of added capture and compression costs on overall project economics is examined.The research reported here suggests that the cost of implementing a CCS-coupled EOR project will be more than is typically assumed; in many cases a positive price on CO2 emitted to the atmosphere will be required to motivate deployment of these CO2-based EOR projects, except in the most idealized cases. The reasons for this conclusion are twofold. First, the costs of capitalizing, operating and monitoring a secondary DSF to provide backup storage for CO2 not demanded by the EOR operation can cut sharply into EOR revenues. Second, except in cases where a single firm figures both the CO2 source emissions and the associated EOR recovery on the same balance sheet, the oil production company is not likely to share a significant portion of revenues from the EOR field with the CO2 source. Thus, while EOR-coupled CCS may offer attractive early opportunities, these opportunities are likely only available to a small fraction of the CO2 source fleet in the U.S

Ariel - Volume 2 Number 6

Editors Richard J. Bonanno Robin A. Edwards Associate Editors Steven Ager Stephen Flynn Shep Dickman Tom Williams Lay-out Editor Eugenia Miller Contributing Editors Michael J. Blecker W. Cherry Light James J. Nocon Lynne Porter Editors Emeritus Delvyn C. Case, Jr. Paul M. Fernhof

An Experiment for Observing Quantum Gravity Phenomena using Twin Table-Top 3D Interferometers

Theories of quantum gravity based on the holographic principle predict the existence of quantum fluctuations of distance measurements that accumulate and exhibit correlations over macroscopic distances. This paper models an expected signal due to this phenomenology, and details the design and estimated sensitivity of co-located twin table-top 3D interferometers being built to measure or constrain it. The experiment is estimated to be sensitive to displacements $\sim10^{-19}\,\rm{m}/\sqrt{\rm{Hz}}$ in a frequency band between 1 and 250 MHz, surpassing previous experiments and enabling the possible observation of quantum gravity phenomena. The experiment will also be sensitive to MHz gravitational waves and various dark matter candidates.Comment: Accepted for publication in Classical and Quantum Gravit

Infection control and the significance of sputum and other respiratory secretions from adult patients with cystic fibrosis

BACKGROUND: There is limited data available on the environmental and public health impact of the microbiological hazards associated with sputa from patients with cystic fibrosis [CF]. Pseudomonas aeruginosa, Burkholderia cenocepacia (formerly Burkholderia cepacia genomovar III), Staphylococcus aureus and Stenotrophomonas maltophilia are bacterial pathogens which are commonly found in the sputum of CF patients. A study was performed to ascertain the amount of sputum produced relating to microbial loading, as well as the diversity of bacteria present in a population of adult patients, with particular attention to pathogenic organisms. METHODS: Sputum from adult [>18 years old] CF patients [n = 20], chosen randomly from a population of 138 CF patients, was collected over a 24 h period on admission to the in-patient CF unit and enumerated quantitatively, as well as the sputa from 138 adult CF patients was examined qualitatively for the presence of infecting microflora. In addition, all different phenotypes from the sputum of each patient were identified phenotypically employing a combination of conventional identification methods [e.g. oxidase], as well as the API Identification schemes [API 20 NE, API 20 E]. RESULTS: This study demonstrated that patients with cystic fibrosis generate large numbers of bacteria in their sputum, approximating to 10(9 )organisms per patient per day. Although these organisms are introduced to the environment from the respiratory tract mainly via sputum, relatively few represent true bacterial pathogens and therefore are not clinically important to the general public who are immunocompotent. The greatest risk of such environmental microbial loading is to other patients with CF and therefore CF patients should be made aware of the hazards of acquiring such organisms from the environment, as well as socializing with other CF patients with certain transmissible types, such as Pseudomonas aeruginosa and Burkholderia cenocepacia. CONCLUSIONS: Environmental health professionals should therefore be aware that CF patients are a greater risk to their peer grouping rather than to the general public or health care workers and that good personal hygiene practices with CF patients should be encouraged to minimize environmental contamination and potential acquistion

Early wound healing of laser in situ keratomileusis?like flaps after treatment with human corneal stromal stem cells

To use a well-established organ culture model to investigate the effects of corneal stromal stem cells on the optical and biomechanical properties of corneal wounds after laser in situ keratomileusis (LASIK)-like flap creation. School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom. Experimental study. The LASIK-like flaps were produced in sheep corneas. The flap beds were treated with corneal stromal stem cells and were then replaced and allowed to heal for different periods of up to 3 weeks in organ culture. The optical transmission of the cornea, the force required to detach the flap, and the presence of myofibroblasts near the flap bed were measured.Corneal stromal stem cell-treated flap beds were statistically significantly more transparent after 3 weeks in culture than the untreated controls. At 3 weeks, the mean force necessary to detach the flap was more than twice the force required for the respective control samples. Concurrently, there were 44% activated cells immediately below the flap margin of the controls compared with 29% in the same region of the corneal stromal stem cell-treated flaps. In this system, the presence of corneal stromal stem cells at the wound margin significantly increased the adherence of LASIK-like flaps while maintaining corneal transparency. It is postulated that this is achieved by the deposition of extracellular connective tissue similar to that found in the normal cornea and by the paucity of activated keratocytes (myofibroblasts), which are known to scatter a significant amount of the incident light. No author has a financial or proprietary interest in any material or method mentioned

Developmental regulation of Foxp3 expression during ontogeny

Thymectomy of neonatal mice can result in the development of autoimmune pathology. It has been proposed that thymic output of regulatory T (T reg) cells is delayed during ontogeny and that the development of autoimmune disease in neonatally thymectomized mice is caused by the escape of self-reactive T cells before thymectomy without accompanying T reg cells. However, the kinetics of T reg cell production within the thymus during ontogeny has not been assessed. We demonstrate that the development of Foxp3-expressing T reg cells is substantially delayed relative to nonregulatory thymocytes during ontogeny. Based on our data, we speculate that induction of Foxp3 in developing thymocytes and, thus, commitment to the T reg cell lineage is facilitated by a signal largely associated with the thymic medulla