2,932 research outputs found
Individual Values and SME Environmental Engagement
We study the values on which managers of small and medium-sized enterprises draw when constructing their personal and organizational-level engagement with environmental issues, particularly climate change. Values play an important mediating role in business environmental engagement but relatively little research has been conducted on individual values in smaller organizations. Using the Schwartz Value System (SVS) as a framework for a qualitative analysis, we identify four ‘ideal-types’ of SME managers and provide rich descriptions of the ways in which values shape their constructions of environmental engagement. In contrast to previous research, which is framed around a binary divide between self-enhancing and self-transcending values, our typology distinguishes between individuals drawing primarily on Power or on Achievement values, and indicates how a combination of Achievement and Benevolence values is particularly significant in shaping environmental engagement. This demonstrates the theoretical usefulness of focusing on a complete range of values. Implications for policy and practice are discussed
Energetic Consequences of the DC-Electric Field Model
We analyze a solar flare observed simultaneously in soft and hard X-rays by instruments onboard Yohkoh and the Compton Gamma Ray Observatory. Assuming a simple one-dimensional coronal loop that is heated by field-aligned currents, we solve the energy balance equation to derive the DC-electric field strength necessary to explain the observed soft X-ray emission by current-dissipation. We use the derived DC-electric field to predict the number flux of electrons accelerated by thermal runaway and compare this prediction with the number flux of nonthermal thick-target electrons implied by impulsive phase hard X-ray observations. We find that runaway acceleration can account for the large flux (approx. greater than 10(exp 36 1/s) of nonthermal electrons provided the loop filling factor is approx. less than 10(exp -3) such that heating and acceleration occur in filamented structures within the loop
Adaptive Networks as a Model for Human Speech Development
Unrestricted English text can be converted to speech through the use of a look up table, or through a parallel feedforward network of deterministic processing units. Here, we reproduce the network structure used in NETtalk. Several experiments are carried out to determine which characteristics of the network are responsible for which learning behavior, and how closely that maps human speech development. The network is also trained with different levels of speech complexity, and with a second language. The results are shown to be highly dependent on statistical characteristics of the input
24R,25-Dihydroxyvitamin D3 Protects against Articular Cartilage Damage following Anterior Cruciate Ligament Transection in Male Rats
Osteoarthritis (OA) in humans is associated with low circulating 25-hydroxyvitamin D3 [25 (OH)D3]. In vitamin D replete rats, radiolabeled 24R,25-dihydroxyvitamin D3 [24R,25 (OH)2D3] accumulates in articular cartilage following injection of [3 H]-25(OH)D3. Previously, we showed that 24R,25(OH)2D3 blocks chondrocyte apoptosis via phospholipase D and p53, suggesting a role for 24R,25(OH)2D3 in maintaining cartilage health. We examined the ability of 24R,25(OH)2D3 to prevent degenerative changes in articular cartilage in an OAlike environment and the potential mechanisms involved. In vitro, rat articular chondrocytes were treated with IL-1β with and without 24R,25(OH)2D3 or 1α,25(OH)2D3. 24R,25(OH)2D3 but not 1α,25(OH)2D3 blocked the effects of IL-1β in a dose-dependent manner, and its effect was partially mediated through the TGF-β1 signaling pathway. In vivo, unilateral anterior cruciate ligament transections were performed in immunocompetent rats followed by intra-articular injections of 24R,25(OH)2D3 or vehicle (t = 0, 7, 14, 21 days). Tissues were harvested on day 28. Joints treated with vehicle had changes typical of OA whereas joints treated with 24R,25(OH)2D3 had less articular cartilage damage and levels of inflammatory mediators. These results indicate that 24R,25(OH)2D3 protects against OA, and suggest that it may be a therapeutic approach for preventing trauma-induced osteoarthritis
Advanced Capabilities for Wind Tunnel Testing in the 21st Century
Wind tunnel testing methods and test technologies for the 21st century using advanced capabilities are presented. These capabilities are necessary to capture more accurate and high quality test results by eliminating the uncertainties in testing and to facilitate verification of computational tools for design. This paper discusses near term developments underway in ground testing capabilities, which will enhance the quality of information of both the test article and airstream flow details. Also discussed is a selection of new capability investments that have been made to accommodate such developments. Examples include advanced experimental methods for measuring the test gas itself; using efficient experiment methodologies, including quality assurance strategies within the test; and increasing test result information density by using extensive optical visualization together with computed flow field results. These points could be made for both major investments in existing tunnel capabilities or for entirely new capabilities
Magnetic Properties of Magnetotactic Bacteria
This paper reports on the magnetic properties of magnetosomes in the freshwater magnetotactic bacterium Aquaspirillum magnetotacticum. The magnetosomes are well crystallized particles of magnetite with dimensions of 40 to 50 nm, which are arranged within the cells in a single linear chain and are within the single-magnetic-domain (SD) size range for magnetite. A variety of magnetic properties have been measured for two samples of dispersions of freeze-dried cells consisting of (1) whole cells (M-1) and (2) magnetosomes chains separated from cells (M-2). An important result is that the acquisition and demagnetization of various type of remanent magnetizations are markedly different for the two samples and suggest that remanence is substantially affected by magnetostatic interactions. Interactions are likely to be much more important in M-2 because the extracted magnetosome chains are no longer separated from one another by the cell membrane and cytoplasm. Other experimental data for whole cells agree with predictions based on the chain of spheres model for magnetization reversal. This model is consistent with the unique linear arrangement of equidimensional particles in A. magnetotacticum. The magnetic properties of bacterial and synthetic magnetites are compared and the paleomagnetic implications are discussed
Historical and Contemporary DNA Indicate Fisher Decline and Isolation Occurred Prior to the European Settlement of California
Establishing if species contractions were the result of natural phenomena or human induced landscape changes is essential for managing natural populations. Fishers (Martes pennanti) in California occur in two geographically and genetically isolated populations in the northwestern mountains and southern Sierra Nevada. Their isolation is hypothesized to have resulted from a decline in abundance and distribution associated with European settlement in the 1800s. However, there is little evidence to establish that fisher occupied the area between the two extant populations at that time. We analyzed 10 microsatelliteloci from 275 contemporary and 21 historical fisher samples (1880-1920) to evaluate the demographic history of fisher in California. We did not find any evidence of a recent (post-European) bottleneck in the northwestern population. In the southern Sierra Nevada, genetic subdivision within the population strongly influenced bottleneck tests. After accounting for genetic subdivision, we found a bottleneck signal only in the northern and central portions of the southern Sierra Nevada, indicating that the southernmost tip of these mountains may have acted as a refugium for fisher during the anthropogenic changes of the late 19th and early 20th centuries. Using a coalescent-based Bayesian analysis, we detected a 90% decline in effective population size and dated the time of decline to over a thousand years ago. We hypothesize that fisher distribution in California contracted to the two current population areas pre-European settlement, and that portions of the southern Sierra Nevada subsequently experienced another more recent bottleneck post-European settlement
The Decline And Isolation Of Fisher Populations Prior To European Settlement: Insights From Dna Analysis
Historical and contemporary genetic information can provide insights into the nature of population expansions or contractions and temporal changes in abundance and connectivity. Fisher (Martes pennanti) populations in California are thought to have declined precipitously over the last 150 yrs and currently only two populations remain in the state that are both geographically and genetically isolated from each other. In this study we looked at whether the isolation of these two populations is a result habitat alteration and trapping that accompanied European settlement in the mid-1800s or if it is the result of a more ancient demographic event. We collected both historical and contemporary genetic samples from each of the two extant fisher populations. We successfully obtained microsatellite genotypes at 10 loci for 21 museum specimens (dated 1882-1920) and 275 contemporary individuals (2006-2009). We found significant temporal shifts in allele frequencies between historical and contemporary samples between regions indicating large amounts of genetic drift likely due to isolation and small population size. We found a strong genetic signal for a 90 percent contraction in effective population size of fisher and estimated that this decline occurred over a thousand years ago. As a decline in abundance of this magnitude likely resulted in contraction of the geographic range, our analyses suggest that fisher populations in California became isolated from one another far prior to the European settlement of the state
Differentially expressed genes in embryonic cardiac tissues of mice lacking Folr1 gene activity
- …