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An imputation/copula-based stochastic individual tree growth model for mixed species Acadian forests： a case study using the nova scotia permanent sample plot network

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Forest Ecosystems 2017年第4期4卷 251-263页

作者： John A. Kershaw Jr Aaron R. Weiskittel Michael B. Lavigne Elizabeth McGarrigle University of New Brunswick FrederictonNBCanada University of Maine OroooMEUSA Atlantic Forestry Centre Natural Resources Canada.FrederiaooNBCanada nova scotia natural resources Forestry DivisionTruroNS B2N 0G9UK.

Background： A novel approach to modelling individual tree growth dynamics is proposed. The approach combines multiple imputation and copula sampling to produce a stochastic individual tree growth and yield projection system. Methods： The nova scotia, Canada permanent sample plot network is used as a case study to develop and test the modelling approach. Predictions from this model are compared to predictions from the Acadian variant of the Forest Vegetation Simulator, a widely used statistical individual tree growth and yield model. Results： Diameter and height growth rates were predicted with error rates consistent with those produced using statistical models. Mortality and ingrowth error rates were higher than those observed for diameter and height, but also were within the bounds produced by traditional approaches for predicting these rates. Ingrowth species composition was very poorly predicted. The model was capable of reproducing a wide range of stand dynamic trajectories and in some cases reproduced trajectories that the statistical model was incapable of reproducing. Conclusions： The model has potential to be used as a benchmarking tool for evaluating statistical and process models and may provide a mechanism to separate signal from noise and improve our ability to analyze and learn from large regional datasets that often have underlying flaws in sample design.

关键词： Nearest neighbor imputation Copula sampling Individual tree growth model Mortality Ingrowth Mixed species stand development Acadian forests nova scotia

Female ticks (Ixodes scapularis) infected with Borrelia burgdorferi have increased overwintering survival, with implications for tick population growth

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Insect Science 2023年第6期30卷 1798-1809页

作者： Amal El Nabbout Laura V.Ferguson Atsushi Miyashita Shelley A.Adamo Department of Biology Dalhousie UniversityHalifaxNova ScotiaCanada Department of Biology Acadia UniversityWolfvilleNova ScotiaCanada Institute of Medical Mycology Teikyo UniversityTokyoJapan Department of Psychology and Neuroscience Dalhousie UniversityNova ScotiaCanada

The tick, Ixodes scapularis, vectors pathogens such as Borrelia burgdorferi, the bacterium that causes Lyme disease. Over the last few decades I. scapularis has expanded its range, introducing a novel health threat into these areas. Warming temperatures appear to be one cause of its range expansion to the north. However, other factors are also involved. We show that unfed adult female ticks infected with B. burgdorferi have greater overwintering survival than uninfected female ticks. Locally collected adult female ticks were placed in individual microcosms and allowed to overwinter in both forest and dune grass environments. In the spring we collected the ticks and tested both dead and living ticks for B. burgdorferi DNA. Infected ticks had greater overwintering survival compared with uninfected ticks every winter for three consecutive winters in both forest and dune grass environments. We discuss the most plausible explanations for this result. The increased winter survival of adult female ticks could enhance tick population growth. Our results suggest that, in addition to climate change, B. burgdorferi infection itself may be promoting the northern range expansion of I. scapularis. Our study highlights how pathogens could work synergistically with climate change to promote host range expansion.

关键词： cold tolerance ecological immunology Lyme disease thermobiology winter

Mercury photoreduction and photooxidation in lakes：Effects of filtration and dissolved organic carbon concentration

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Journal of Environmental Sciences 2018年第6期30卷 151-159页

作者： Nelson J.O’Driscoll Emma Vost Erin Mann Sara Klapstein Robert Tordon Matthew Lukeman Department of Earth & Environmental Science Acadia University Wolfville B4P 2R6 Nova Scotia Canada Environment Canada Dartmouth Nova Scotia Canada Department of Chemistry Acadia University Wolfville B4P 2R6 Nova Scotia Canada

Mercury is a globally distributed, environmental contaminant. Quantifying the retention and loss of mercury is integral for predicting mercury-sensitive ecosystems. There is little information on how dissolved organic carbon（DOC） concentrations and particulates affect mercury photoreaction kinetics in freshwater lakes. To address this knowledge gap,samples were collected from ten lakes in Kejimkujik National Park, nova scotia（DOC： 2.6–15.4 mg/L）. Filtered（0.2 μm） and unfiltered samples were analysed for gross photoreduction, gross photooxidation, and net reduction rates of mercury using pseudo first-order curves. Unfiltered samples had higher concentrations（p = 0.04） of photoreducible divalent mercury（Hg（II）RED）（mean of 754 ± 253 pg/L） than filtered samples（mean of 482 ± 206 pg/L）;however, gross photoreduction and photooxidation rate constants were not significantly different in filtered or unfiltered samples in early summer. DOC was not significantly related to gross photoreduction rate constants in filtered（R2= 0.43; p = 0.08） and unfiltered（R2= 0.02; p = 0.71） samples; DOC was also not significantly related to gross photooxidation rate constants in filtered or unfiltered samples. However, DOC was significantly negatively related with Hg（Ⅱ）RED in unfiltered（R2= 0.53; p = 0.04）, but not in filtered samples（R2= 0.04;p = 0.60）. These trends indicate that DOC is a factor in determining dissolved mercury photoreduction rates and particles partially control available Hg（Ⅱ）RED in lake water. This research also demonstrates that within these lakes gross photoreduction and photooxidation processes are close to being in balance. Changes to catchment inputs of particulate matter and DOC may alter mercury retention in these lakes and could partially explain observed increases of mercury accumulation in biota.

关键词： Mercury Photoreduction Photooxidation Dissolved organic carbon(DOC) Particulates Kejimkujik National Park

A Simple Geospatial Nutrient Budget Model for Assessing Forest Harvest Sustainability across nova scotia, Canada

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Open Journal of Forestry 2016年第5期6卷 420-444页

作者： Kevin Keys Joshua D. Noseworthy Jae Ogilvie David L. Burton Paul A. Arp nova scotia Department of natural resources Truro Nova Scotia Faculty of Forestry and Environmental Management UNB Fredericton New Brunswick Department of Environmental Sciences Agricultural Campus Dalhousie University Truro Nova Scotia

A geospatial GIS-linked spreadsheet model (Nutrient Budget Model—nova scotia: NBM-NS) was developed for nova scotia to assess the long-term sustainability of forest harvest scenarios as constrained by primary nutrient inputs and outputs due to atmospheric deposition, soil weathering, and leaching. Harvest scenarios refer to user-defined stand-specific removal rates of bole wood, bark, branches, and foliage, based on current or projected forest inventories. These scenarios are evaluated within the context of existing data layers for current climate (mean annual precipitation and air temperatures), atmospheric deposition (N, S, Ca, Mg, K), and soil/substrate types, supplemented by species-specific look-up tables containing expected biomass fractions and nutrient concentrations. This article introduces this model to assess relative site quality and limiting nutrients for red spruce and sugar maple across nova scotia. This is followed by an output comparison involving 25 spruce plantations whereby NBM-NS determinations derived using “default” soil survey data are compared with those derived using plantation-specific soil data. Model output shows that (i) Ca and N are the main growth-limiting nutrients across nova scotia, (ii) currently projected plantation yields are generally not sustainable on sites underlain by slowly weathering soils, (iii) current soil base cation contents are generally lower than what is reported in historic soil survey reports, and (iv) model results are expected to vary within the context of changing climate, acid deposition levels, and data accuracy.

关键词： Forest Nutrition Management Biomass Harvesting Sustainable Forest Management Forest Plantation Management

Impacts of climate change on seasonal extreme waves in the Northwest Atlantic using a Spatial Neural Gas clustering method

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Journal of Ocean Engineering and Science 2023年第4期8卷 367-385页

作者： Hamid Goharnejad Will Perrie Bash Toulany Mike Casey Minghong Zhang Fisheries and Oceans Canada Bedford Institute of OceanographyDartmouthNova ScotiaCanada

Having estimates of wave climate parameters and extreme values play important roles for a variety of different societal activities,such as coastal management,design of inshore and offshore structures,marine transport,coastal recreational activities,fisheries,*** study investigates the efficiency of a state-of-the-art spatial neutral gas clustering method in the classification of wind/wave data and the evaluation of extreme values of significant wave heights(Hs),mean wave direction(MWD)and mean wave periods(T0)for two 39-year time periods;from 1979 to 2017 for the present climate,and from 2060 to 2098,for a future climate change scenario in the Northwest *** data were constructed by application of a numerical model,WAVEWATCHIII TM(hereafter,WW3),to simulate the wave climate for the study area for both present and future *** from the model was extracted for the wave climate,in terms of the wave parameters,specifically Hs,MWD and T0,which were analyzed and compared for winter and summer seasons,for present and future *** order to estimate extreme values in the study area,a natural Gas(hereafter,NG)clustering method was applied,separate clusters were identified,and corresponding centroid points were *** analyze data at each centroid point,time series of wave parameters were extracted,and using standard stochastic models,such as Gumbel,exponential and Weibull distribution functions,the extreme values for 50 and 100-year return periods were ***,the impacts of climate change on wave regimes and extreme values can be specified.

关键词： Extreme wave parameters WW3 RCP8.5 Spatial neural gas clustering method

An incidental case of Wellens＇ syndrome in a community emergency department

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World Journal of Emergency Medicine 2016年第2期7卷 153-156页

作者： Deep Jaiswal Dan Boudreau Faculty of Medicine Dalhousie University Halifax Nova Scotia Canada

INTRODUCTION Wellens'syndrome,also called left anterior descending(LAD)coronary T-wave syndrome,is a characteristic electrocardiographic(ECG)pattern suggestive of coronary artery disease in the preinfarction stage.^([1–3])ECG changes in Wellens'syndrome may signify critical stenosis in the proximal LAD coronary artery.^([1–5])Furthermore。

关键词： NSTEMI An incidental case of Wellens syndrome in a community emergency department LAD ECG case

End-tidal capnometry during emergency department procedural sedation and analgesia： a randomized, controlled study

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World Journal of Emergency Medicine 2016年第1期7卷 13-18页

作者： Samuel G. Campbell Kirk D. Magee Peter J. Zed Patrick Froese Glenn Etsell Alan LaPierre Donna Warren Robert R. MacKinley Michael B. Butler George Kovacs David A. Petrie Department of Emergency Medicine and Anesthesia Dalhousie University Halifax Nova Scotia Canada Faculty of Pharmaceutical Sciences and Department of Emergency Medicine University of British Columbia Vancouver BC Canada Charles V. Keating Emergency and Trauma Centre Halifax Nova Scotia Canada Department of Emergency Medicine Anesthesia and Anatomy Dalhousie University Halifax Nova Scotia Canada

BACKGROUND:This prospective,randomized trial was undertaken to evaluate the utility of adding end-tidal capnometry(ETC)to pulse oximetry(PO)in patients undergoing procedural sedation and analgesia(PSA)in the emergency department(ED).METHODS:The patients were randomized to monitoring with or without ETC in addition to the current standard of *** endpoints included respiratory adverse events,with secondary endpoints of level of sedation,hypotension,other PSA-related adverse events and patient ***:Of 986 patients,501 were randomized to usual care and 485 to additional ETC *** this series,48%of the patients were female,with a mean age of 46 *** manipulations(71%),cardioversion(12%)and abscess incision and drainage(12%)were the most common procedures,and propofol and fentanyl were the sedative/analgesic combination used for most *** was no difference in patients experiencing de-saturation(Sa O2<90%)between the two groups;however,patients in the ETC group were more likely to require airway repositioning(12.9%vs.9.3%,P=0.003).Hypotension(SBP<100 mm Hg or<85 mm Hg if baseline<100 mm Hg)was observed in 16(3.3%)patients in the ETC group and 7(1.4%)in the control group(P=0.048).CONCLUSIONS:The addition of ETC does not appear to change any clinically significant *** found an increased incidence of the use of airway repositioning maneuvers and hypotension in cases where ETC was *** do not believe that ETC should be recommended as a standard of care for the monitoring of patients undergoing PSA.

关键词： Procedural sedation and analgesia Capnography Adverse events Emergency medicine

Corrigendum to Mercury photoreduction and photooxidation in lakes:effects of filtration and dissolved organic carbon *** of Environmental Sciences 68(2018)151-159

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Journal of Environmental Sciences 2021年第5期33卷 347-350页

作者： Nelson J.O'Driscol Emma Vost Erin Mann Sara Klapstein Robert Tordon Matthew Lukeman Department o f Earth&Environmental Science.Acadia University WolfuilleNova ScotiaCanada B4P 2R62 Environment Canada DartmouthNova Scotia Department of Chemistry Acadia UniversityWolfuilleNova ScotiaCanada B4P 2R6

"Filtered(0.2μm)and unfiltered samples were analyzed for gross photoreduction,gross photooxidation,and net reduction rates of mercury using pseudo first-order curves.

关键词： lakes Mercury dissolved

Characterizing objective and self-report habitual physical activity and sedentary time in outpatients with an acquired brain injury

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Sports Medicine and Health Science 2024年第4期6卷 338-343页

作者： Liam P.Pellerine Katerina Miller Ryan J.Frayne Myles W.O'Brien Division of Kinesiology School of Health and Human PerformanceFaculty of HealthDalhousie UniversityHalifaxNova ScotiaCanada Acquired Brain Injury NeuroCommons Nova Scotia Health AuthorityHalifaxNova ScotiaCanada School of Physiotherapy(Faculty of Health)&Department of Medicine(Faculty of Medicine) Dalhousie UniversityHalifaxNova ScotiaCanada Geriatric Medicine Research Dalhousie University&Nova Scotia HealthHalifaxNova ScotiaCanada Centre de Formation Medicale Du Nouveau-Brunswick New Brunswick&Department of MedicineUniversite de SherbrookeSherbrookeQuebecCanada

Outpatients with an acquired brain injury(ABI)experience physical,mental,and social *** can be classified into two subgroups based on mechanism of injury:mild traumatic brain injury(mTBI;e.g.,concussion)and other ABI(e.g.,stroke,brain aneurysm,encephalitis).Our understanding of habitual activity levels within ABI populations is limited because they are often collected using self-report *** purpose of this study was to,1)describe the habitual activity levels of outpatients with ABI using objective and self-report monitoring,and 2)compare the activity levels of outpatients with mTBI *** *** outpatients with other ABI(mean±standard deviation:[58±13]years,9 females)and 12 outpatients with mTBI([48±11]years,9 females)wore a thigh-worn activPAL 24 h/day(h/day)for *** with ABI averaged(6.0±2.3)h/day of upright time,(10.6±2.2)h/day of sedentary time,(5.6±2.7)h/day in prolonged sedentary bouts>1 h,(5960±3037)steps/day,and(11±13)minutes/day(min/day)of moderate-vigorous physical activity(MVPA).There were no differences between activPAL-derived upright,sedentary,prolonged sedentary time,and physical activity between the mTBI and other ABI groups(all,p>0.31).Outpatients with ABI overestimated their MVPA levels(t138 min/week)and underestimated sedentary time(-4.3 h/day)compared to self-report(all,p<0.001).Despite self-reporting high activity levels,outpatients with ABI objectively exhibit highly inactive and sedentary *** habitual movement behaviours of our sample did not differ by mechanism of injury(i.e.,mTBI versus other ABI).Targeting reductions in objectively measured sedentary time are needed to progressively improve the habitual movement behaviours of outpatients with ABI.

关键词： Accelerometry Stroke Brain aneurysm Encephalitis Mild traumatic brain injury Rehabilitation