DEVELOPING STRATEGIES TO INITIALIZE LANDSCAPE-SCALE VEGETATION MAPS FROM FIA DATA TO ENHANCE RESOLUTION OF INDIVIDUAL SPECIES-SIZE COHORT REPRESENTATION IN THE LANDSCAPE DISTURBANCE MODEL, SIMPPLLE

The ability of forest resource managers to understand and anticipate landscape-scale change in composition and structure relies upon an adequate characterization of the current forest composition and structure of various patches (or stands), along with the capacity of forest landscape models (FLMs) to predict patterns of growth, succession, and disturbance at multiple scales over time. Comprehensive vegetation maps, which classify patch polygons or raster cells into forest cover types, can be developed from available inventory data (e.g., FIA Grid) in combination with remotely sensed data, but a simple categorical forest type, even one incorporating average size, may not provide adequate resolution for tracking individual species and age cohorts over time in an FLM. This project, undertaken in Eastern Montana forest types, sought to develop strategies for utilizing extensive inventory data from the U.S. Forest Inventory and Analysis (FIA) program to initialize patch-level vegetation information for use in the landscape disturbance model SIMPPLLE (Chew et al 2004). The information provided to SIMPPLLE, includes not only a forest cover dominance type that crosswalks with the Northern Region’s VMAP labels, but also incorporates further species and size information to the cohort level. By processing FIA data through the stand-level growth model FVS (Forest Vegetation Simulator), tracking of individual cohorts could be summarized to enhance resolution and realism in the SIMPPLLE model. Further, by simulating patch level dynamics within FVS for up to 300 years for representative stands, and segregating growing stock by cohort, it was possible to enhance the complexity of stand development pathways to be used within SIMPPLLE model. Specifically, I enable the tracking of individual cohorts (species and 5” breast-height diameter size class) to be passed on to the SIMPPLLE model, while still allowing for large-scale modeling of disturbances and between-patch interactions, which are the scales of interest within the SIMPPLLE FLM

An evaluation of user acceptance of a corporate intranet

Intranets represent an important organisational resource for knowledge sharing. However, as yet, there has been little research into the quality of intranets and the impact of quality on intranet user acceptance. In the study reported in this paper, an intranet quality assessment tool comprising the dimensions usability, design, and information quality, is combined with perceived usefulness and social influence from the technology acceptance literature to create an intranet acceptance model. The model is applied to the sales and marketing division of an international manufacturing company. Data is collected via a Web survey (n=131, response rate = 65.5%) and tested using the partial least squares approach to structural equation modelling. The results show that intranet quality is a significant factor in determining behavioural intention to use, although it is less important than perceived usefulness and social influence. Comments collected from respondents are used to illustrate the findings and provide an insight into user behaviour. The discussion considers the implications, future research (e.g., the role of social influence in intranet usage) and limitations. The paper rounds off with a short summary

Estimating the marginal value of agricultural irrigation water: A methodology and empirical application to the Berg River Catchment

This study aims to facilitate effective and efficient intersectoral water allocation policy in South Africa, where limited water supplies are increasingly constraining necessary economic development. The study develops an economic model of irrigated agricultural production that recognises the multi-output nature of irrigated agriculture as well as the institutional setting in which commercial irrigation water is allocated in South Africa. The model is then used to econometrically estimate the marginal value of commercial irrigation water in the Berg Water Management Area (WMA), using a Translog functional form, Tobit censored regression model, including controls for heterogeneity, and accounting for heteroscedasticity. The estimates are obtained for 16 irrigated crops in the region and range from an overall mean of 4.84 R/m³ for peaches to 0.14 R/m³ for wheat, but vary significantly between sub-regions and according to soil productivity as well as between crops. Furthermore, the estimates differ substantially from the average value of production per m³ of irrigation water, reflecting a revenue-water elasticity that differs from unity for all crops. The results imply that potential efficiency gains are possible from the intersectoral reallocation of water away from agriculture. A further implication is that reallocation within the agricultural sector would be most efficiently undertaken by farmers themselves, due to the large number factors that affect irrigation water productivity but are unobservable by policymakers or are difficult to account for in the formulation of policy

Stealing the Show: KSHV Hijacks Host RNA Regulatory Pathways to Promote Infection

Kaposi’s sarcoma-associated herpesvirus (KSHV) induces life-long infections and has evolved many ways to exert extensive control over its host’s transcriptional and post-transcriptional machinery to gain better access to resources and dampened immune sensing. The hallmark of this takeover is how KSHV reshapes RNA fate both to control expression of its own gene but also that of its host. From the nucleus to the cytoplasm, control of RNA expression, localization, and decay is a process that is carefully tuned by a multitude of factors and that can adapt or react to rapid changes in the environment. Intriguingly, it appears that KSHV has found ways to co-opt each of these pathways for its own benefit. Here we provide a comprehensive review of recent work in this area and in particular recent advances on the post-transcriptional modifications front. Overall, this review highlights the myriad of ways KSHV uses to control RNA fate and gathers novel insights gained from the past decade of research at the interface of RNA biology and the field of KSHV research

Electrically Enhanced Free Dendrite Growth in Polar and Non-polar Systems

We describe the electrically enhanced growth of needle crystals from the vapor phase, for which there exists a morphological instability above a threshold applied potential. Our improved theoretical treatment of this phenomenon shows that the instability is present in both polar and non-polar systems, and we provide an extension of solvability theory to include electrical effects. We present extensive experimental data for ice needle growth above the electrical threshold, where at $T=-5$C high-velocity shape-preserving growth is observed. These data indicate that the needle tip assumes an effective radius} $R^{\ast}$ which is nearly independent of both supersaturation and the applied potential. The small scale of $R^{\ast}$ and its response to chemical additives suggest that the needle growth rate is being limited primarily by structural instabilities, possibly related to surface melting. We also demonstrate experimentally that non-polar systems exhibit this same electrically induced morphological instability

Does adult ADHD interact with COMT val 158 met genotype to influence working memory performance?

Peer reviewedPostprin

The Wind‐ISM Interaction of α Tauri

Ultraviolet spectra of α Tau (K5 III) obtained by the Hubble Space Telescope (HST) show many emission lines affected by broad absorption from the strong wind of this red giant star. For the Mg II h and k lines there is also a narrow absorption feature in the midst of the wind absorption that has been interpreted as being from α Tau\u27s wind-interstellar medium (ISM) interaction region (i.e., its astrosphere ). We try to reproduce this absorption using hydrodynamic models of the α Tau astrosphere, which show that stellar wind material heated, compressed, and decelerated at the wind\u27s termination shock (TS) can produce significant absorption at about the right velocity. By experimenting with different model input parameters, we find that the parameter that the absorption is most sensitive to is the ISM pressure, which determines the location of and therefore the density at the TS. However, the models underestimate both the amount of deceleration at the TS and the amount of absorption for realistic input parameters. We demonstrate that these problems can in principle be resolved by modeling the TS as a radiative shock. However, a cooling timescale short enough to affect the postshock flow is only attainable if α Tau\u27s wind speed is increased from the 27-30 km s-1 values derived from fits to wind absorption to at least 35 km s-1. The models also seem to require a very high ISM pressure of P/k ≈ 30,000 cm-3 K to induce densities at the TS high enough to yield sufficient radiative cooling. This pressure is at least a factor of 2 higher than other estimates of ISM thermal pressure within the Local Bubble