Introduction. The outbreaks of the Zaire ebolavirus (ZE) disease (ZED) that have arisen in the last decade determine the need to study the infection pathogenesis, the formation of specific immunity ...forming as well as the development of effective preventive and therapeutic means. All stages of fight against the ZED spread require the experimental infection in sensitive laboratory animals, which are rhesus monkeys in case of this disease .The aim of the study is to evaluate the rhesus monkey cellular immunity following the ZE experimental infection by the means of flow cytometry (cytofluorimetry).Material and methods. Male rhesus monkeys were intramuscularly infected by the dose of 15 LD50 (dose of the pathogen that causes 50% mortality of infected animals) of the ZE, the Zaire strain (ZEBOV). Levels of 18 peripheral blood lymphocyte populations of the animals before the ZE experimental infection and at the terminal stage of the disease were assessed using flow cytometry.Results and discussion. The certain changes in the levels of the lymphocyte populations were observed following infection, indicating simultaneous activation and suppression of the immune system during ZED. The increase in content was observed for T-lymphocytes, T-helper and cytotoxic T-lymphocytes expressing the corresponding markers of early activation. The decrease was recorded for T-lymphocytes and double-positive T-lymphocytes expressing corresponding markers of late activation, as well as natural killer cells expressing CD8 (p 0.05).Conclusion. For the first time in the Russian Federation, the rhesus monkey cellular immunity before and after the ZE experimental infection was assessed using flow cytometry.
Warming temperatures and rising moisture deficits are expected to increase the rates of background tree mortality–low amounts of tree mortality (~0.5%–2% year−1), characterizing the forest ...demographic processes in the absence of abrupt, coarse‐scale disturbance events (e.g. fire). When compounded over multiple decades and large areas, even minor increases in background tree mortality (e.g. <0.5% year−1) can cause changes to forest communities and carbon storage potential that are comparable to or greater than those caused by disturbances.
We examine how temporal variability in rates of background tree mortality for four subalpine conifers reflects variability in climate and climate teleconnections using observations of tree mortality from 1982 to 2019 at Niwot Ridge, Colorado, USA. Individually marked trees (initial population 5,043) in 13 permanent plots—located across a range of site conditions, stand ages and species compositions—were censused for new mortality nine times over 37 years.
Background tree mortality was primarily attributed to stress from unfavourable climate and competition (71.2%) and bark beetle activity (23.3%), whereas few trees died from wind (5.3%) and wildlife impacts (0.2%). Mean annualized tree mortality attributed to tree stress and bark beetles more than tripled across all stands between initial censuses (0.26% year−1, 1982–1993/1994) and recent censuses (0.82% year−1, 2008–2019). Higher rates of tree mortality were related to warmer maximum summer temperatures, greater summer moisture deficits, and negative anomalies in ENSO (La Niña), with greater effects of drought in some subpopulations (tree size, age and species). For example, in older stands (>250 years), larger and older trees were more likely to die than smaller and younger trees. Differences in tree mortality rates and sensitivity to climate among subpopulations that varied by stand type may lead to unexpected shifts in stand composition and structure.
Synthesis. A strong relationship between higher rates of tree mortality and warmer, drier summer climate conditions implies that climate warming will continue to increase background mortality rates in subalpine forests. Combined with increases in disturbances and declining frequency of moist‐cool years suitable for seedling establishment, increasing rates of tree mortality have the potential to drive declines in subalpine tree populations.
Rates of background tree mortality increased from 1982–2019 in subalpine forests in Colorado. Higher rates of background tree mortality occurred during summers with warmer and drier climate conditions. Though the sensitivity of tree mortality to climate differed by tree species and tree size classes, climate warming will continue to increase tree mortality throughout subalpine forests. Image: Recently killed subalpine fir tree in an Engelmann spruce‐subalpine fir forest in Colorado.
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In contrast to abrupt changes caused by land cover conversion, subtle changes driven by a shift in the condition, structure, or other biological attributes of land often lead to minimal and slower ...alterations of the terrestrial surface. Accurate mapping and monitoring of subtle change are crucial for an early warning of long-term gradual change that may eventually result in land cover conversion. Freely accessible moderate-resolution datasets such as the Landsat archive have great potential to characterize subtle change by capturing low-magnitude spectral changes in long-term observations. However, past studies have reported limited success in accurately extracting subtle changes from satellite-based time series analysis. In this study, we introduce a supervised framework named ‘PIDS’ to detect subtle forest disturbance from a comprehensive Landsat data archive by leveraging disturbance-based calibration sites. PIDS consists of four components: (1) Parameter optimization; (2) Index selection; (3) Dynamic stratified monitoring; and (4) Spatial consideration. PIDS was applied to map the early stage of bark beetle infestations (i.e., a lower per-pixel fraction of trees cover that show visual signs of infestation), which are a typical example of subtle change in conifer forests. Landsat Analysis Ready Data were used as the time series inputs for mapping mountain pine beetle and spruce beetle disturbance between 2001 and 2019 in Colorado, USA. PIDS-detection map assessment showed that the overall performance of PIDS (namely ‘F1 score’) was 0.86 for mountain pine beetle and 0.73 for spruce beetle, making a substantial improvement (> 0.3) compared to other approaches/products including COntinuous monitoring of Land Disturbance, LandTrendr, and the National Land Cover Database forest disturbance product. A sub-pixel analysis of tree canopy mortality percentage was performed by linking classified high-resolution (0.3- and 1-m) aerial imagery and 30-m PIDS-detection maps. Results show that PIDS typically detects mountain pine beetle infestation when ≥56% of a Landsat pixel is occupied by red-stage canopy mortality (one year after initial infestation), and spruce beetle infestation when ≥55% is occupied by gray-stage mortality (two years after initial infestation). This study addresses an important methodological goal pertinent to the utility of event-based reference samples for detecting subtle forest change, which could be potentially applied to other types of subtle land change.
•Develop a framework for detecting subtle changes from satellite time series.•Automatically calibrate model parameters and optimize spectral indices.•Assess results using multiple sources including field data and aerial survey.•Reach >0.3 F1 score improvement compared to other approaches.•Subpixel analysis for detected beetle stage using high-resolution imagery.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
► Effects of age or dose regimen on cholinesterase inhibition by chlorpyrifos/oxon. ► No age-dependent differences in chlorpyrifos cholinesterase inhibition. ► Pups had lower cholinesterase ...inhibition at comparable blood chlorpyrifos levels. ► Dose rate caused differential effects on cholinesterase inhibition across tissues. ► Chlorpyrifos–oxon inhibited red blood cell but not brain cholinesterase.
The effect of age or dose regimen on cholinesterase inhibition (ChEI) from chlorpyrifos (CPF) or CPF–oxon (CPFO) was studied in Crl:CD(SD) rats. Rats were exposed to CPF by gavage in corn oil, rat milk (pups), or in the diet (adults) or to CPFO by gavage in corn oil. Blood CPF/CPFO levels were measured. With acute exposure, ChEI NOELs were 2mg/kg CPF for brain and 0.5mg/kg CPF for red blood cells (RBCs) in both age groups. In pups, ChEI and blood CPF levels were similar using either milk or corn oil vehicles. Compared to gavage, adults given dietary CPF (12h exposure) had greater RBC ChEI, but lower brain ChEI at corresponding CPF doses, indicating an effect of dose rate. With repeated CPF exposures, ChEI NOELs were the same across ages (0.5 and 0.1mg/kg/day for brain and RBCs, respectively). With CPFO dosing, the ChEI NOELs were 0.1mg/kg (acute) and 0.01mg/kg/day (repeated doses) for RBCs with no ChEI in brain at CPFO doses up to 0.5 (pup) or 10mg/kg (adult) for acute dosing or 0.5mg/kg/day for both ages with repeat dosing. Thus, there were no age-dependent differences in CPF ChEI via acute or repeated exposures. Pups had less ChEI than adults at comparable blood CPF levels. Oral CPFO resulted in substantial RBC ChEI, but no brain ChEI, indicating no CPFO systemic bioavailability to peripheral tissues.
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Acute toxicologic and neurotoxic effects were evaluated in Fischer 344 rats exposed to 0, 50, 200, 600, or 2000
ppm 1,2-dichloroethane (ethylene dichloride; EDC) for 4
h or 0, 50, 100 or 150
ppm for ...8
h. Neurobehavioral and neuropathologic effects were assessed using a functional observational battery (FOB; baseline, days 1, 8, and 15), and by light microscopy, respectively. Acute toxicologic effects were assessed by bronchoalveolar lavage (BAL) and histopathology of the respiratory tract and selected target organs. Neurobehavioral effects consistent with central nervous system (CNS) depression were present at concentrations >200
ppm and were restricted to day 1. There were no neuropathologic changes in the CNS, however, olfactory epithelial regeneration 15
days after exposure to ⩾200
ppm was observed. The no-observed-effect concentration (NOEC) for behavioral neurotoxicity was 200
ppm EDC for 4
h. There were no effects on BAL parameters in any exposure group. Exposure to 2000
ppm EDC altered adrenal gland, kidney, and liver weights, and resulted in morphologic alterations in the kidney and liver. Degeneration/necrosis of the olfactory epithelium was observed at ⩾200
ppm for 4
h and ⩾100
ppm for 8
h. Based on olfactory epithelial degeneration/necrosis, the most sensitive indicator of toxicity in this study, the overall NOEC was 50
ppm EDC for up to 8
h in rats.
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Meal prepared from Cry1F/Cry1Ac transgenic/genetically modified cottonseed (WIDESTRIKE™ Insect Protection, hereafter referred to as WIDESTRIKE™) was compared to cottonseed meal prepared from four ...conventionally bred lines of cotton (three commercial non-transgenic line controls (PHY72, PHY78 and 98M-2983), and a near isoline non-transgenic control (PSC355) in a 90-day dietary study to evaluate safety and nutritional equivalence. Diets were formulated with 10% WIDESTRIKE™ cottonseed meal equivalent to 7235
mg/kg/day for males and 7935
mg/kg/day for females. Animals were evaluated by cage-side and hand-held detailed clinical observations, body weight, and feed consumption. Functional tests, motor activity and ophthalmic examinations were conducted pre-exposure and prior to study termination. Standard hematology, clinical chemistry, prothrombin time and urinalysis parameters were evaluated. All rats had a complete necropsy and selected organs were weighed. Histopathologic examinations were performed on all rats fed the diets containing the near isoline non-transgenic control or WIDESTRIKE™.
Following 90
days of feeding, no adverse effects were observed during the conduct of clinical observations or in any of the parameters measured in this study. This study demonstrated that rodent diets prepared with 10% cottonseed meal from WIDESTRIKE™ cottonseeds do not produce any untoward effects and are nutritionally equivalent to cottonseed meals prepared from other, non-transgenic cottonseeds.
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As forest fire activity increases worldwide, it is important to track changing patterns of burn severity (i.e., degree of fire‐caused ecological change). Satellite data provide critical information ...across space and time, yet how satellite indices relate to individual measures of burn severity on the ground (e.g., tree mortality or surface charring) and how these relationships change across biophysical gradients remain unclear. To address these knowledge gaps, we used Bayesian hierarchical zero‐one‐inflated beta (ZOIB) regression models with nearly 600 plots of individual field measures of burn severity distributed across the U.S. Rocky Mountains. We asked the following: How do three commonly used satellite indices of burn severity relate to individual field measures of canopy burn severity and forest‐floor burn severity (Q1)? Then, using the highest ranked satellite index, how is reliability affected by biophysical gradients that can be captured in accessible geospatial data (e.g., latitude, slope) (Q2) and stand‐structure data typically available only with field data (Q3)? The Relative differenced Normalized Burn Ratio (RdNBR) outperformed the differenced Normalized Burn Ratio (dNBR) and the Relative Burn Ratio (RBR) across canopy and forest‐floor measures of burn severity, but differences among index performances were minor. Overall, indices performed better for field measures of canopy burn severity than for forest‐floor measures. The relationship between RdNBR and individual field measures of burn severity changed across several biophysical gradients. For example, the same value of RdNBR corresponded to different field levels of burn severity depending on latitude, pre‐fire forest structure, and pre‐fire beetle outbreaks—and effects of biophysical gradients were often different for canopy vs. forest‐floor measures of burn severity. We show that estimating field measures of burn severity using satellite indices can be improved by including biophysical information, but if variables that are difficult to obtain without field data (e.g., pre‐fire beetle outbreak severity) are lacking, we suggest caution in interpreting satellite indices of burn severity across gradients of pre‐fire biophysical conditions. Finally, using an example fire, we illustrate contrasting maps of burn severity that arise from differences in the relationship between individual field measures of burn severity and RdNBR after accounting for error in those relationships.
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Ongoing changes in fire regimes have the potential to drive widespread shifts in Earth's vegetation. Plant traits and vital rates provide insight into vulnerability to fire‐driven vegetation shifts ...because they can be indicators of the ability of individuals to survive fire (resistance) and populations to persist (resilience) following fire.
In 15 study sites spanning climatic gradients in the southern Rocky Mountains, USA, we quantified variation in key traits and vital rates of two co‐occurring, widely distributed conifers (Pinus ponderosa Douglas ex. P. Lawson & C. Lawson and Pseudotsuga menziesii (Mirb.) Franco). We used mixed‐effects models to explain inter‐ and intraspecific variation in tree growth, survival, bark thickness and seed cone production, as a function of species, tree life stage (i.e. diameter, height and age), average climate, local competition and site conditions.
Pinus ponderosa was predicted to survive low‐severity fire at a 23% earlier age than P. menziesii. Pinus ponderosa had thicker bark and more rapid juvenile height growth, traits conferring greater fire resistance. In contrast, P. menziesii was predicted to produce seed cones at a 28% earlier age than P. ponderosa. For both species, larger individuals were more likely to survive fire and to produce cones. For P. ponderosa, cone production increased where average actual evapotranspiration (AET) was higher and local competition was lower. More frequent cone production on productive sites with higher AET is an important and underappreciated mechanism that may help to explain greater resilience to fire in these areas.
Synthesis. Our analyses indicated that many plant traits and vital rates related to fire differed between Pinus ponderosa and Pseudotsuga menziesii, with trade‐offs between investment in traits that promote individual defence to fire and those that promote recolonization of disturbed sites. Future changes in fire regimes will act as a filter throughout North American forests, with our findings helping to infer which individuals and populations of two iconic species are most vulnerable to future change and offering a framework for future inquiry in other forests facing an uncertain future.
Plant traits and vital rates differed among populations of Pinus ponderosa and Pseudotsuga menziesii, with apparent trade‐offs between investment in traits that promote individual defence to fire (e.g. bark thickness, time to fire‐resistant size) and those that promote recolonization of disturbed sites (e.g. seed cone production). Future changes in fire regimes will act as a filter throughout North American forests, with our findings helping to infer which individuals and populations of two iconic species are most vulnerable to future change and offering a framework for future inquiry in other forests facing an uncertain future.
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Recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western North America. To date, ...the majority of studies examining bark beetle outbreaks and subsequent fire severity in the U.S. Rocky Mountains have focused on outbreaks of mountain pine beetle (MPB; Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests, but few studies, particularly field studies, have addressed the effects of the severity of spruce beetle (Dendroctonus rufipennis Kirby) infestation on subsequent fire severity in subalpine Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests. In Colorado, the annual area infested by spruce beetle outbreaks is rapidly rising, while MPB outbreaks are subsiding; therefore understanding this relationship is of growing importance. We collected extensive field data in subalpine forests in the eastern San Juan Mountains, southwestern Colorado, USA, to investigate whether a gray-stage (<5 yr from outbreak to time of fire) spruce beetle infestation affected fire severity. Contrary to the expectation that bark beetle infestation alters subsequent fire severity, correlation and multivariate generalized linear regression analysis revealed no influence of pre-fire spruce beetle severity on nearly all field or remotely sensed measurements of fire severity. Findings were consistent across moderate and extreme burning conditions. In comparison to severity of the pre-fire beetle outbreak, we found that topography, pre-outbreak basal area, and weather conditions exerted a stronger effect on fire severity. Our finding that beetle infestation did not alter fire severity is consistent with previous retrospective studies examining fire activity following other bark beetle outbreaks and reiterates the overriding influence of climate that creates conditions conducive to large, high-severity fires in the subalpine zone of Colorado. Both bark beetle outbreaks and wildfires have increased autonomously due to recent climate variability, but this study does not support the expectation that post-beetle outbreak forests will alter fire severity, a result that has important implications for management and policy decisions.
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Climate-induced increases in tree mortality are reported for many forests worldwide. Understanding the potential effects on carbon pools requires long-term monitoring of changes in forest biomass. We ...measured aboveground biomass (AGB) of living trees over a 34-year period (1982–2016) in permanent plots with varying stand ages, species compositions, and topographic settings in a subalpine forest in the Colorado Front Range. Stand-level and species-level AGB varied spatially and temporally in relation to stand age, successional processes, and site moisture classification. Young (ca. 122 years) postfire stands composed of lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) had lower mean AGB than older (>250 years) mixed-species stands. Mesic stands had higher AGB than xeric or hydric stands of similar age. At the level of individual species, significant shifts in AGB among species were primarily explained by successional replacement of shade-intolerant pines by shade-tolerant Engelmann spruce (Picea engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.). The permanent plot network recorded significant shifts in species dominance and tree densities between 1982 and 2016, reflecting successional patterns developing over several centuries and the effects of recent localized windthrow, insects, and pathogens. Despite increases in tree mortality, there was a general pattern of increasing AGB across the forest.
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