Power-law behavior reveals phase transitions in landscape controls of fire regimes

In low-severity fire regimes of the American West and elsewhere, landscape memory of fire events is registered in fire-scarred trees, with temporal record lengths often exceeding 200 years^1-5^. Understanding the environmental controls on historical wildfires, and how they changed across spatial scales, is difficult because there are no surviving explicit records of either weather or vegetation (fuels). We show how power laws associated with fire-event time series arise in limited domains of parameters that represent critical transitions in the controls on landscape fire. We used stochastic simulations iteratively with Monte Carlo inference to replicate the spatio-temporal structure of historical fire-scar records in forested watersheds of varying topographic complexity. We find that the balance between endogenous and exogenous controls on fire spread shifts with topographic complexity, where in the most complex landscapes the endogenous controls dominate and the pattern exhibits criticality. Comparison to an self-organized criticality (SOC) model^6,7^ shows that the latter mimics historical fire only in a limited domain of criticality, and is not an adequate mechanism to explain landscape fire dynamics, which are shaped by both endogenous and exogenous controls. Our results identify a continuous phase transition in landscape controls, marked by power laws, and provide an ecological analogue to critical behavior in physical and chemical systems^8-11^. This explicitly cross-scale analysis provides a paradigm for identifying critical thresholds in landscape dynamics that may be crossed in a rapidly changing climate

Taking the Northern Bobwhite Conservatino Initiative to the Next Level

During the last few decades of the 20th century, changing and intensifying human uses of land converted and rendered unsuitable hundreds of millions of acres of northern bobwhite (Colinus virginianus) habitats, resulting in a long-term population decline of 3.8% per year across the Southeast. During that period, bobwhite conservation efforts were largely ineffectual. Following the success of other national bird conservation initiatives, the Southeastern Association of Fish and Wildlife Agencies (SEAFWA) in 1998 charged its technical arm, the Southeast Quail Study Group (SEQSG) to develop a regional, habitat-based bobwhite recovery plan with population goals and habitat objectives. The Northern Bobwhite Conservation Initiative (NBCI) was published in March 2002, as the first-ever ecosystem-based regional management plan for a resident game bird in the U.S. The NBCI catalyzed immediate major successes in conservation policy, priority, energy and actions, such as the new ”Habitat Buffers for Upland Birds” practice in the Conservation Reserve Program. The NBCI also stimulated unprecedented unity of purpose and collective will across the bobwhite community, under the leadership of the SEQSG. A thorough revision of the NBCI already is in progress, coordinated by Tall Timbers Research Station

MONITORING THE ELITE ATHLETE

The application of sports medicine technology to the practical aspect of sport has led to the common belief that the scientific preparation of the athlete is the responsibility of a team -a coach, biomechanist, physician, exercise pysiologist, sport psychologist and others. The advent of sophisticated physiological equipment to determine specific objective measures of performance during activity has allowed the coach to perceive the athlete in precise scientific terms. This monitoring process is a contemporary yet controversial issue. To what extent does applied science impinge of this article is to review the different facets of monitoring with specific emphasis on the overtraining phenomena. The monitoring process can generally be divided into three separate phases: medical, physiological and assessment of overtraining

An investigation of the effects which using the word processor has on the writing of standard six pupils

In order to discover to what extent the use of the word processor affects the motivation of high school students when engaged in writing tasks, and to determine the effects of the word processing on the length and quality of their work and editing, two groups, carefully matched in terms of prior computer experience, intelligence and language ability were given eight writing tasks. The test group used word processors while the control group used pen and paper. Their behaviour was closely observed and their writing was subsequently compared. It was found that while the test group were more motivated and spent longer both writing and editing their work, the quality of the work of both groups was similar. The degree of editing was greater for the test group. The conclusion is that there is a place for the use of the word processor in the English classroom, but specific strategies need to be developed to optimise its benefits

Muscle oxygenation trends after tapering in trained cyclists

BACKGROUND: This study examined muscle deoxygenation trends before and after a 7-day taper using non-invasive near infrared spectroscopy (NIRS). METHODS: Eleven cyclists performed an incremental cycle ergometer test to determine maximal oxygen consumption (VO(2)max = 4.68 ± 0.57 L·min(-1)) prior to the study, and then completed two or three high intensity (85–90% VO(2)max) taper protocols after being randomly assigned to a taper group: T30 (n = 5), T50 (n = 5), or T80 (n = 5) [30%, 50%, 80% reduction in training volume, respectively]. Physiological measurements were recorded during a simulated 20 km time trials (20TT) performed on a set of wind-loaded rollers. RESULTS AND DISCUSSION: The results showed that the physiological variables of oxygen consumption (VO(2)), carbon dioxide (VCO(2)) and heart rate (HR) were not significantly different after tapering, except for a decreased ventilatory equivalent for oxygen (V(E)/VO(2)) in T50 (p ≤ 0.05). However, during the 20TT muscle deoxygenation measured continuously in the vastus medialis was significantly lower (-749 ± 324 vs. -1140 ± 465 mV) in T50 after tapering, which was concomitant with a 4.53% improvement (p = 0.057) in 20TT performance time, and a 0.18 L·min(-1 )(4.5%) increase in VO(2). Furthermore, when changes in performance time and tissue deoxygenation (post- minus pre-taper) were plotted (n = 11), a moderately high correlation was found (r = 0.82). CONCLUSION: It was concluded that changes in simulated 20TT performance appeared to be related, in part, to changes in muscle deoxygenation following tapering, and that NIRS can be used effectively to monitor muscle deoxygenation during a taper period

Comparative gene transfer efficiency of low molecular weight polylysine DNA-condensing peptides

In a previous report (M.S. Wadhwa et al . (1997) Bioconjugate Chem. 8, 81–88), we synthesized a panel of polylysine-containing peptides and determined that a minimal repeating lysine chain of 18 residues followed by a tryptophan and an alkylated cysteine residue (AlkCWK 18 ) resulted in the formation of optimal size (78 nm diameter) plasmid DNA condensates that mediated efficient in vitro gene transfer. Shorter polylysine chains produced larger DNA condensates and mediated much lower gene expression while longer lysine chains were equivalent to AlkCWK 18 . Surprisingly, AlkCWK 18 (molecular weight 2672) was a much better gene transfer agent than commercially available low molecular weight polylysine (molecular weight 1000–4000), despite its similar molecular weight. Possible explanations were that the cysteine or tryptophan residue in AlkCWK 18 contributed to the DNA binding and the formation of small condensates or that the homogeneity of AlkCWK 18 relative to low molecular weight polylysine facilitated optimal condensation. To test these hypotheses, the present study prepared AlkCYK 18 and K 20 and used these to form DNA condensates and conduct in vitro gene transfer. The results established that DNA condensates prepared with either AlkCYK 18 or K 20 possessed identical particle size and mediated in vitro gene transfer efficiencies that were indistinguishable from AlkCWK 18 DNA condensates, eliminating the possibility of contributions from cysteine or tryptophan. However, a detailed chromatographic and electrospray mass spectrometry analysis of low molecular weight polylysine revealed it to possess a much lower than anticipated average chain length of dp 6. Thus, the short chain length of low molecular weight polylysine explains its inability to form small DNA condensates and mediate efficient gene transfer relative to AlkCWK 18 DNA condensates. These experiments further emphasize the need to develop homogenous low molecular weight carrier molecules for nonviral gene delivery.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74767/1/j.1399-3011.1999.00104.x.pd

Progress of the National Bobwhite Conservation Initiative

Northern bobwhites (Colinus virginianus) have declined precipitously over 5 decades because of a decline in habitat, largely a result of agricultural intensification and inadequate management of natural plant succession. In response, quail biologists developed strategic and operational plans, and formed a national partnership of state and federal agencies, bobwhite institutions, non-government organizations, universities and private citizens. The early history of these efforts was reviewed in 2006 at the Sixth National Quail Symposium. Over the past 10 years, exponential growth occurred, including establishment of a home for national bobwhite conservation at the University of Tennessee, and funding from the National Fish and Wildlife Foundation, the United States Fish Wildlife Service Pitmann-Robertson (Federal Aid in Wildlife Restoration Program), individual state agencies and citizens. The result in 2016 is the National Bobwhite Conservation Initiative (NBCI), a 25-state consortium of state wildlife agencies and partners, led by the National Bobwhite Technical Committee and NBCI Management Board. In 2011, NBCI published an updated strategic restoration plan, and spatially-explicit planning tool, NBCI 2.0, followed in 2014 by an implementation plan, the NBCI Coordinated Implementation Program (CIP). We update the history of the NBCI, including changes in funding mechanisms, leadership, administration, and technical programs, and we assess current opportunities and the future of bobwhite conservation

Unexpected effects of urban food activism on community and human wellbeing

Open Access via the Taylor & Francis/JISC Open Select agreement This project was funded by the University of Aberdeen and the Wellcome Trust through the Sustainable and Healthy Food Systems (SHEFS) project (Grant number 205200/Z/16/Z).Peer reviewedPublisher PD

VARIATIONS IN THE RESPONSES OF C57BL/10J AND A/J MICE TO SHEEP RED BLOOD CELLS : I. SEROLOGICAL CHARACTERIZATION AND GENETIC ANALYSIS

In response to repeated injections of sheep red blood cells, C57BL/10J mice produce predominantly 19S antibody in increasingly higher amounts, while A/J mice initially produce 19S antibody and then switch to produce increasing 7S antibody titers. In an F1 generation all mice responded like the C57BL/10J mice. Backcross data implied genetic control involving at least three loci

Balancing Uncertainty and Complexity to Incorporate Fire Spread in an Eco-Hydrological Model

Wildfire affects the ecosystem services of watersheds, and climate change will modify fire regimes and watershed dynamics. In many eco-hydrological simulations, fire is included as an exogenous force. Rarely are the bidirectional feedbacks between watersheds and fire regimes integrated in a simulation system because the eco-hydrological model predicts variables that are incompatible with the requirements of fire models. WMFire is a fire-spread model of intermediate complexity designed to be integrated with the Regional Hydro-ecological Simulation System (RHESSys). Spread in WMFire is based on four variables that (i) represent known influences on fire spread: litter load, relative moisture deficit, wind direction and topographic slope, and (ii) are derived directly from RHESSys outputs. The probability that a fire spreads from pixel to pixel depends on these variables as predicted by RHESSys. We tested a partial integration between WMFire and RHESSys on the Santa Fe (New Mexico) and the HJ Andrews (Oregon State) watersheds. Model assessment showed correspondence between expected spatial patterns of spread and seasonality in both watersheds. These results demonstrate the efficacy of an approach to link eco-hydrologic model outputs with a fire spread model. Future work will develop a fire effects module in RHESSys for a fully coupled, bidirectional model