Whitebark Pine ecology and management: synthesizing current understanding

Whitebark pine (Pinus albicaulis), an ecologically important tree species of high-elevation ecosystems of western North America, is declining across most of its range due to the combined effects of an invasive pathogen (blister rust; Cronartium ribicola) and a native insect (mountain pine beetle; Dendroctonus ponderosae), as well as climate-change-induced increases in wildfire frequency and severity. Concern over these threats to whitebark pine as well as successional replacement by shade-tolerant firs has led to its listing under both the US and Canadian Endangered Species Acts and an increase in research activities. In addition, management agencies have adopted coordinated, trans-boundary restoration strategies (e.g., Range-Wide Restoration Strategy for Whitebark Pine and the National Whitebark Pine Restoration Plan) that call for silvicultural treatments and prescribed burning, among other interventions. Despite a growing literature and widespread agreement on the need for conservation and restoration, there is little synthetic information on the species ecology, successional dynamics, and response to management interventions. In order to identify gaps in knowledge and improve restoration strategies for white bark pine, we conducted a literature review on the status of knowledge on the species in general. Specifically, we identified all publications listed on Web of Science and grey literature available on AGRICOLA (National Agricultural Library, USDA) from 1950 to 2018 using the search terms whitebark pine and “Pinus albicaulis”. We only reviewed articles that mentioned the species in the abstract or title, or studies in which whitebark pine ecosystems were a main focus. Although the number of published articles has been increasing over the last 30 years, most studies focused on biotic interactions (27%), pathogens and MPB outbreaks (39%), mortality (35%), and regeneration dynamics (25%). On the other hand, there was very little available information on the efficacy and effects of restoration and other management activities (less than 10% of all articles). There were also few articles published on the species life history, fire ecology and successional dynamics. Our findings indicate a significant gap in information required for effective conservation and restoration of whitebark pine. To improve capacity for successful management of whitebark pine, there is a need to invest in research that aligns with conservation needs

Ecological effects of prescribed burning, mechanical cutting, and post-treatment wildfire for restoration of Pinus albicaulis

The field of ecological restoration is growing rapidly, increasing the need for reliable and generalizable information on the impacts of management interventions aimed to be restorative. Prescribed burning and mechanical cutting have been proposed as primary strategies for restoration. However, there is limited information on their efficacy and effects in subalpine forest types, suggesting that monitoring to inform adaptive management is a priority need. I used data from a 15-year, replicated before-after-control-impact (BACI) study on Pinus albicaulis (whitebark pine) restoration to assess the ecological effects of prescribed burning and mechanical cutting, with and without subsequent unplanned wildfire, as well as the efficacy of the monitoring design. Mature tree mortality was high across all study units (77-100%), but neither treatment type nor wildfire were significant predictors of mortality. Similarly, I was unable to detect any effects of treatments or wildfire on P. albicaulis basal area, which declined over time across all study units. However, I found a significant effect of treatment on basal area for two (Pinus contorta and Picea engelmannii) of the three competing conifer species. At Bear Overlook, the site not affected by wildfire, P. contorta basal area change varied significantly between the two treatment units; it decreased by 2.1 m2ha-1 in the burn-only unit but increased by 2.4 m2ha-1 in the prescribed burn with mechanical cutting unit; however, neither treatment was significantly different from the control unit. In contrast, at Beaver Ridge, the prescribed burn with mechanical control treatments, both with and without wildfire, resulted in significant reductions of P. contorta basal area (by 9.8 m2ha-1 and 4.1 m2ha-1, respectively), compared to the untreated control (which did not experience wildfire), which increased by 1 m2ha-1. For P. engelmannii, at Bear Overlook, the site not affected by wildfire, basal area increased after treatment (by 10.3 m2ha-1 and 2.6 m2ha-1 in the burn-only and prescribed burning with mechanical cutting, respectively), but these increases did not differ from changes in the control unit (7.2 m2ha-1). Pinus albicaulis seedling density decreased across both sites and all treatments, however, response to treatment was not statistically significant, while response to wildfire was. The most precisely estimated variable was basal area with a 34% margin of error, followed by mortality (47%) and seedling density (71%). Overall, my findings reveal that the restoration treatments did not affect P. albicaulis mature tree mortality, basal area or seedling density, and were not consistently effective at reducing pressure from competing conifers 15-years after treatment. Although the study utilized best practice design (BACI) and had a relatively large number of replicates (n= 5), loss of study sites due to wildfire coupled with low precision of estimation in field measurements limited power of detection, and highlights the need for large-scale long-term monitoring networks and innovative sampling designs to improve understanding of the efficacy and effects of restoration treatments in P. albicaulis and other degraded forest ecosystems

Dynamical system analysis of ignition phenomena using the tangential stretching rate concept

We analyze ignition phenomena by resorting to the stretching rate concept formerly introduced in the study of dynamical systems. We construct a Tangential Stretching Rate (TSR) parameter by combining the concepts of stretching rate with the decomposition of the local tangent space in eigen-modes. The main feature of the TSR is its ability to identify unambiguously the most energetic scale at a given space location and time instant. The TSR depends only on the local composition of the mixture, its temperature and pressure. As such, it can be readily computed during the post processing of computed reactive flow fields, both for spatially homogeneous and in-homogenous systems. Because of the additive nature of the TSR, we defined a normalized participation index measuring the relative contribution of each mode to the TSR. This participation index to the TSR can be combined with the mode amplitude participation Index of a reaction to a mode – as defined in the Computational Singular Perturbation (CSP) method – to obtain a direct link between a reaction and TSR. The reactions having both a large participation index to the TSR and a large CSP mode amplitude participation index are those contributing the most to both the explosive and relaxation regimes of a reactive system. This information can be used for both diagnostics and for the simplification of kinetic mechanisms. We verified the properties of the TSR with reference to three nonlinear planar models (one for isothermal branched-chain reactions, one for a non-isothermal, one-step system, and for non-isothermal branched-chain reactions), to one planar linear model (to discuss issues associated with non-normality), and to test problems involving hydro-carbon oxidation kinetics. We demonstrated that the reciprocal of the TSR parameter is the proper characteristic chemical time scale in problems involving multi-step chemical kinetic mechanisms, because (i) it is the most relevant time scale during both the explosive and relaxation regimes and (ii) it is intrinsic to the kinetics, that is, it can be identified without the need of any ad hoc assumption

Contact dermatitis in children

Contact dermatitis in pediatric population is a common but (previously) under recognized disease. It is usually divided into the allergic and the irritant forms

Critical concepts, practice recommendations, and research perspectives of pixantrone therapy in non-Hodgkin lymphoma: a SIE, SIES, and GITMO consensus paper

Objectives: In this paper, we present a review of critical concepts and research perspectives and produce recommendations on the optimal use of pixantrone in non-Hodgkin lymphoma (NHL) by group discussion from an expert panel appointed by the Italian Society of Hematology and the affiliate societies, Societa Italiana di Ematologia Sperimentale and Gruppo Italiano Trapianto di Midollo Osseo. Methods: Recommendations were produced using the Delphi process. Scientific evidence on pixantrone efficacy was analyzed using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology in the areas where at least one randomized trial was published. The following key issues were addressed for practical recommendations: pixantrone monotherapy in aggressive relapsed or refractory non-Hodgkin B-cell lymphomas and toxicity risk management in patients candidates to pixantrone. Results and conclusions: After a balanced and value-oriented discussion, the panel agreed that the benefit/risk profile was in favor of pixantrone in the treatment of adult patients with multiply relapsed or refractory aggressive NHL B-cell lymphomas. Pixantrone was deemed to be contraindicated in patients with uncontrolled cardiovascular disease. Despite a low rate of cardiotoxicity of pixantrone reported in clinical trials, the panel recommended that all patients receiving pixantrone should undergo periodical cardiac monitoring

Measuring IEEE 802.11p Performance for Active Safety Applications in Cooperative Vehicular Systems

Abstract-In this paper, we present a measurement study of application layer performance in IEEE 802.11p vehicular networks. More specifically, our focus is on active safety applications, which are based on the exchange of beacon messages containing status information between close-by vehicles. We consider two performance metrics relevant to active safety applications: the first is application-layer goodput, which can be used to optimize congestion control techniques aimed at limiting the beaconing load on the wireless channel; the second is the beacon reception rate, which is useful to estimate the level of situation awareness achievable onboard vehicles. Our measurements were conducted using a prototypal, 802.11p compliant communication device developed by NEC, in both stationary and mobile V2V scenarios, and disclosed several useful insights on 802.11p application-level performance. To the best of our knowledge, the ones presented in this paper are the first application-level measurements of IEEE 802.11p based vehicular networks reported in the literature

Reproductive Biology and Natural History of the White-lipped Pit Viper (\u3cem\u3eTrimeresurus albolabris\u3c/em\u3e Gray, 1842) in Hong Kong

The White-lipped Pit Viper (Trimeresurus albolabris) is broadly distributed through South and Southeast Asia, and very little is known about the natural history of the species. In this study, we report on the ecology, demography, reproductive states, and growth rates of T. albolabris in Hong Kong, China. The sex ratio is even in Trimeresurus albolabris populations. This species displays sexual dimorphism from birth. Females attain larger sizes, and all males, including neonates, displaying a white supralabial stripe on the head and have longer relative tail lengths. Males attain sexual maturity at about 410 mm snout-vent length (SVL). Females reach sexual maturity at about 460 mm SVL, but only begin reproducing at about 520 mm SVL. Mating occurs between August to October, coinciding with the onset of spermatogenesis. Trimeresurus albolabris displays post-nuptial vitellogenesis, and long-term sperm storage in females likely occurs over the winter. Females gestate over the summer and parturition occurs in late July to August. Females reproduce once every two or more years, except for very large females that may reproduce annually. Brumation by females occurs within the first three weeks of December, but snakes will emerge to bask on sunny days. Understanding its demography and reproductive ecology can provide insights into the conservation and management of T. albolabris populations in the region and increase our understanding of sexual dimorphism, reproduction, and evolution of the cryptic Trimeresurus species complex

The IPERMOB System for Effective Real-Time Road Travel Time Measurement and Prediction

Accurate, real-time measurement and estimation of road travel time is considered a central problem in the design of advanced Intelligent Transportation Systems. In particular, whether eective, real-time collection of travel time measurements in a urban area is possible is, to the best of our knowledge, still an open problem. In this paper, we introduce the IPERMOB system for efficient, real-time collection of travel time measurements in urban areas through vehicular networks. We demonstrate that travel time measurements can be accurately estimated onboard GPS-equipped vehicles, and delivered to a centralized server within a few seconds by sending a single message. Furthermore, in IPERMOB locations of travel time checkpoints can be dynamically changed through software reconfiguration, thus at a very limited cost as compared to the enormous costs of, say, installing and/or changing location of automatic vehicle identification equipment. We demonstrate the effectiveness of our approach through extensive travel time collection campaigns. In particular, our technique is shown to estimate travel time with an accuracy below 1%, with two-, three-orders of magnitude savings in both communication and storage resources with respect to existing techniques based on centralized collection of GPS traces. In the last part of the paper, we further show how real-time travel time measurements can be exploited to perform accurate, short range travel time predictions in situations where existing travel time prediction approaches are challenged (e.g., in presence of traffic congestion). The effects of vehicular network penetration rate on accuracy of travel time prediction are also discusse

Assessing the Performance of a MIMO SDR Testbed with Dual Transceiver Implementation

Software Defined Radio testbeds are becoming increasingly used in the wireless networking community, given their feature of leaving wireless network designer full control of the PHY layer. On the other hand, SDR testbeds are formed of very complex software/hardware tools, in which implementation bugs are likely and difficult to identify. For this reason, assessment of the results provided by an SDR platform should be a fundamental, preliminary step in the performance evaluation process. In this paper, we provide a thorough assessment of the MIMONet SDR platform for network-level exploitation of MIMO technology. To assess the platform, we have used two different implementations of an OFDM transceiver: one based on Matlab, the other on the GNU Radio software. We have then crossvalidated performance by means of extensive measurements using the two alternative implementations. We have also designed and implemented a fine grained SNR and BER estimation methodology, that allowed us to carefully validate performance of the two software implementations against theoretical predictions. When collectively considered, the results of our measurements promote MIMONet as the first SDR testbed with carefully validated performance