Impacts of the sustainable forestry initiative landscape level measures on hydrological processes

The effects on hydrological processes of the application of the landscape level measures included in the sustainable forestry initiative (SFI) program were analyzed through simulation. A landscape scenario where limitation of harvesting units’ size, imposition of a green-up interval, and establishment of streamside management zones (SMZ) were simulatedwas compared with a reference scenario where no SFI rules were followed. An intensively managed forested landscape located in East Texas, USA, was used as the study area. The HARVEST landscape model was used to simulate landscape pattern and a modified version of the APEX model was used to simulate hydrological processes. Water and sediment yields were generally small within the observation period and most of the runoff and erosion observed occurred during intense storm events. Water and sediment yield at the subarea level and water yield at the watershed level were similar in both scenarios. However, sediment yield at the watershed level was higher in the non-SFI scenario. The differences were due to the reduction in channel erosion resulting from the presence of SMZs. The effect of buffer zones in terms of sediment deposition was not different between scenarios, which can be attributed to the level slopes of the study area. Landscape measures of the SFI program, namely buffer zones, seem important in reducing channel degradation, particularly during major storm events, in intensively managed forest landscapes in East Texas.PRODEP II

A real space renormalization group approach to spin glass dynamics

The slow non-equilibrium dynamics of the Edwards-Anderson spin glass model on a hierarchical lattice is studied by means of a coarse-grained description based on renormalization concepts. We evaluate the isothermal aging properties and show how the occurrence of temperature chaos is connected to a gradual loss of memory when approaching the overlap length. This leads to rejuvenation effects in temperature shift protocols and to rejuvenation--memory effects in temperature cycling procedures with a pattern of behavior parallel to experimental observations.Comment: 4 pages, 4 figure

Effects of the Sustainable Forestry Initiative on Landscape Pattern and Processes

We used simulation modeling to study the changes in landscape pattern and function resulting from the application of the Sustainable Forestry Initiative (SFI) program in East Texas, USA. Changes in landscape structure were examined by comparing landscapes with different management histories. The effects of pattern on processes were analyzed considering vertebrate habitat quality and configuration and hydrological processes such as water and sediment yield. Landscapes managed according to the SFI program presented increased general fragmentation. The application of measures under SFI increased habitat diversity in the landscape as well as Habitat Suitability Index (HSI) values for most of the species. Habitat for species requiring large patches of mature forest was almost absent. Landscapes managed under the SFI program showed lower sediment yield at the watershed level than those under the non-SFI program due to higher channel erosion related to the absence of buffer strips in the non-SFI scenario

The role of the sustainable forestry Initiative in forest landscape changes in Texas, USA

We studied the changes in landscape pattern and function resulting from the application of the Sustainable Forestry Initiative (SFI) in East Texas, USA. Changes in landscape structure were studied by comparing land-scapes with different management histories. A methodology to integrate landscape and stand pattern dynamics with processes was developed based upon modeling and simulation. The effects of pattern on processes were analyzed with this methodology considering the quality, quantity and con-figuration of vertebrate habitat and hydrological processes. Comparisons among landscapes revealed that forest management has a strong influence on landscape structure. The SFI program has increased overall fragmentation with an increase in number of patches, length of edges and shape complexity and a decrease in patch size, and number and size of core areas. Management according to the SFI program resulted generally in higher habitat suitability for many of the species analyzed and higher habitat di-versity in the landscape. The SFI program induced fragmentation of the habitat of pine warbler and the establishment of narrow and elongated habitats in a network structure for most of the remaining species. Land-scapes managed under the SFI program showed lower sediment yield at the watershed level than those under the non-SFI program due to lower channel erosion. The effects of the SFI program at the landscape level are related to the network of buffer strips. In general we conclude that relevant measures at the landscape level improve the sustainability of forested landscapes in East Texas

Structural and electrical properties of c-axis oriented Y1-xCaxBa2(Cu1-yZny)3O7-delta thin films grown by pulsed laser deposition

Ca- and Zn-subsituted Y1-xCaxBa2(Cu1-yZny)O7-delta (x = 0, 0.05 and y = 0, 0.02, 0.04, 0.05) thin films were grown on SrTiO3 (100) substrates using the pulsed laser deposition (PLD) technique. Effects of various growth parameters on the quality of the film were studied via X-ray diffraction (XRD), atomic force microscopy (AFM), and in-plane resistivity, rhoab(T), measurements. The deposition temperature and oxygen partial pressure were gradually increased to 820C and 1.20 mbar respectively. Films grown under these conditions exhibited good c-axis orientation (primarily limited by the grain size) and low values of the extrapolated residual resistivity, rho(0), at zero temperature. The planar hole content, p, was determined from the room temperature thermopower, S[290K], measurements and the effects of oxygen annealing were also studied. Fully oxygenated samples were found to be overdoped with p ~ 0.195. The Superconducting transition temperature Tc(p), and rho(T,p) showed the expected systematic variations with changing Zn content.Comment: Submitted to Physica C (2003

Social Media and Well-being: A Methodological Perspective

Due to the methodological challenges inherent in studying social media use (SMU), as well as the methodological choices that have shaped research into the effects of SMU on well-being, clear conclusions regarding relationships between SMU and well-being remain elusive. We provide a review of five methodological developments poised to provide increased understanding in this domain: (1) increased use of longitudinal and experimental designs; (2) the adoption of behavioural (rather than self-report) measures of SMU; (3) focusing on more nuanced aspects of SMU; (4) embracing effect heterogeneity; and (5) the use of formal modelling and machine learning. We focus on how these advances stand to bring us closer to understanding relations between SMU and well-being, as well as the challenges associated with these developments

Mixed initial conditions to estimate the dynamic critical exponent in short-time Monte Carlo simulation

We explore the initial conditions in short-time critical dynamics to propose a new method to evaluate the dynamic exponent z. Estimates are obtained with high precision for 2D Ising model and 2D Potts model for three and four states by performing heat-bath Monte Carlo simulations.Comment: Latex paper, 2 eps figure

Monte Carlo Simulations with Indefinite and Complex-Valued Measures

A method is presented to tackle the sign problem in the simulations of systems having indefinite or complex-valued measures. In general, this new approach is shown to yield statistical errors smaller than the crude Monte Carlo using absolute values of the original measures. Exactly solvable, one-dimensional Ising models with complex temperature and complex activity illustrate the considerable improvements and the workability of the new method even when the crude one fails.Comment: 10 A4 pages, postscript (140K), UM-P-93-7

Magneto-Transport Properties of Doped RuSr2_2GdCu2_2O8_8

RuSr$_2$GdCu$_2$O$_8$, in which magnetic order and superconductivity coexist with $T_{Magnetic}$$\gg$$T_c$, is a complex material which poses new and important questions to our understanding of the interplay between magnetic and superconducting (SC) order. Resistivity, Hall effect and thermopower measurements on sintered ceramic RuSr$_2$GdCu$_2$O$_8$ are presented, together with results on a broad range of substituted analogues. The Hall effect and thermopower both show anomalous decreases below $T_{Magnetic}$ which may be explained within a simple two-band model by a transition from localized to more itinerant behavior in the RuO$_2$ layer at $T_{Magnetic}$.Comment: 10 pages, 7 figures, submitted to Phys. Rev. B., correspondence to [email protected]