scholarly journals Influence of Climate on Carbon Sequestration in Conifers Growing under Contrasting Hydro-Climatic Conditions

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1134
Author(s):  
Andrea Cecilia Acosta-Hernández ◽  
Jaime Roberto Padilla-Martínez ◽  
José Ciro Hernández-Díaz ◽  
José Angel Prieto-Ruiz ◽  
José Rodolfo Goche-Telles ◽  
...  
Keyword(s):  
Climate Changes ◽  
Drought Index ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Climatic Variability ◽  
Climatic Conditions ◽  
Carbon Accumulation ◽  
Climatic Variables ◽  
Ecological Functions ◽  
Carbon Cycles

Research Highlights: Analyzing the contrasting ecological gradients makes it easier to understand the influence of climate on carbon accumulation. Background and Objectives: The increasing climatic variability has implications for vegetation, impacting on its ecological functions, among which carbon accumulation stands out. In the present study, we used climate-dendrochronology relationships to evaluate carbon accumulation in two conifer species that grow in contrasting humidity sites: Pinus strobiformis Engelm (mesic sites) and Pinus leiophylla var. chihuahuana (Engelm.) Shaw (arid sites). Materials and Methods: Using a dendrochronological approach, we estimated the correlation of biomass and carbon accumulation of each species with some climatic variables (temperature, precipitation, and a drought index) and generated a linear mixed model. Results: The response in carbon accumulation between species with respect to climate was significantly different. P. strobiformis showed a positive correlation with the climatic variables analyzed, while in P. leiophylla the correlation was negative, except with precipitation. Conclusions: These results show that forests in both mesic and arid sites are prone to climate changes, although their responses are different, impacting the productivity and carbon cycles of forest ecosystems.

scholarly journals A Fumonisin Prevention Tool for Targeting and Ranking Agroclimatic Conditions Favoring Exposure in French Maize-Growing Areas

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 214
Author(s):  
Agathe Roucou ◽  
Christophe Bergez ◽  
Benoît Méléard ◽  
Béatrice Orlando
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Fusarium Verticillioides ◽  
Agricultural Practices ◽  
Climatic Conditions ◽  
Agricultural Cooperatives ◽  
Mixed Model Approach ◽  
Food And Feed ◽  
Model Approach

The levels of fumonisins (FUMO)—mycotoxins produced by Fusarium verticillioides—in maize for food and feed are subject to European Union regulations. Compliance with the regulations requires the targeting of, among others, the agroclimatic factors influencing fungal contamination and FUMO production. Arvalis-Institut du végétal has created a national, multiyear database for maize, based on field survey data collected since 2003. This database contains information about agricultural practices, climatic conditions and FUMO concentrations at harvest for 738 maize fields distributed throughout French maize-growing regions. A linear mixed model approach highlights the presence of borers and the use of a late variety, high temperatures in July and October, and a water deficit during the maize cycle as creating conditions favoring maize contamination with Fusarium verticillioides. It is thus possible to target a combination of risk factors, consisting of this climatic sequence associated with agricultural practices of interest. The effects of the various possible agroclimatic combinations can be compared, grouped and classified as promoting very low to high FUMO concentrations, possibly exceeding the regulatory threshold. These findings should facilitate the creation of a national, informative and easy-to-use prevention tool for producers and agricultural cooperatives to manage the sanitary quality of their harvest.

Probing the relationship between formaldehyde column concentrations and soil moisture using mixed models and attribution analysis

2020 ◽  
Author(s):  
Susanna Strada ◽  
Josep Penuelas ◽  
Marcos Fernández Martinez ◽  
Iolanda Filella ◽  
Ana Maria Yanez-Serrano ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Drought Index ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Numerical Models ◽  
Positive Trend ◽  
Temperature And Precipitation ◽  
The Impact ◽  
The Relationship

<p align="justify">In response to changes in environmental factors (e.g., temperature, radiation, soil moisture), plants emit biogenic volatile organic compounds (BVOCs). Once released in the atmosphere, BVOCs influence levels of greenhouse gases and air pollutants (e.g., methane, ozone and aerosols), thus affecting both climate and air quality. In turn, climate change may alter BVOC emissions by modifying the driving environmental conditions and by increasing the occurrence and intensity of severe stresses that alter plant functioning. To understand and better constrain the evolution of BVOC emissions under future climates, it is important to reduce the uncertainties in global and regional estimates of BVOC emissions under present climate. Part of the uncertainty in the estimates of BVOC emissions is related to the impact that water stress might have on BVOC emissions. Field campaign, in-situ and laboratory experiments investigated the effect of different regimes of water stress (short- vs. long-term) on BVOC emissions. However, these studies provide geographically scattered and uneven results. To explore the relationship between BVOC emissions and water stress globally, we use remotely sensed soil moisture and formaldehyde, a proxy of BVOC emissions. As BVOCs include a multitude of gas tracers with lifetime ranging from few hours to days, a fully characterisation of these components is virtually impossible. Nevertheless, in the continental boundary layer, formaldehyde is an intermediate by-product of the oxidation of BVOCs, it thus provides a proxy for probing local BVOC emissions, and in particular isoprene, which accounts for about 50% of the total BVOC emissions.</p><p align="justify">In the present study, retrievals of formaldehyde from the Ozone Monitoring Instrument (OMI) are combined with observations of soil moisture, biomass, aerosols, evapotranspiration, drought index, temperature and precipitation. Firstly, we look into the linear annual trend of the selected fields. Secondly, assuming formaldehyde as the dependent variable, we apply a linear mixed model analysis that extends the application of a simple linear regression model by accounting for both fixed (i.e., explained by the independent variables) and random (i.e., due to dependence in the data) effects. The analysis of the linear trend of formaldehyde concentrations shows a positive trend over the Amazon and Central Africa and a negative trend over South Africa and Australia. Over the Amazon, formaldehyde is negatively correlated with the Standardised Precipitation-Evapotranspiration Index (SPEI), a drought index that accounts for both changes in temperature and precipitation, with positive and negative values identifying wet and dry events, respectively. The outcomes of this analysis might provide new insights in the relationship between BVOC emissions and water stress and might help in improving parameterizations that link soil moisture to BVOC emissions in numerical models.</p>

Impact of Climatic Conditions on Physical Activity: A 2-Year Cohort Study in the Arabian Gulf Region

2016 ◽  
Vol 13 (9) ◽  
pp. 929-937 ◽  
Author(s):  
Abdulla S. Al-Mohannadi ◽  
Abdulaziz Farooq ◽  
Angus Burnett ◽  
Mercia Van Der Walt ◽  
Mohamed Ghaith Al-Kuwari
Keyword(s):  
Physical Activity ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Cohort Analysis ◽  
Arabian Gulf ◽  
Climatic Conditions ◽  
World Health ◽  
Gulf Region ◽  
Arabian Gulf Region ◽  
Temperature And Humidity

Background:Little is known about the effects that climatic conditions, especially extreme heat, have on physical activity (PA) levels. The aim of this 2-year cohort analysis undertaken in the Arabian Gulf region was to assess changes in objectively-assessed PA as a result of changes in climatic conditions.Methods:A total of 2088 adults (1390 men and 698 women) from many regions of the world were enrolled in a community health program in Qatar, were included in this study. For 2 years participants recorded daily step count using an Omron HJ-720 ITC pedometer. Daily climate parameters included temperature, relative humidity and other conditions.Results:From linear mixed model analysis it was evident that higher average temperature and humidity, and the Wet bulb Globe Temperature (WbGT), resulted in a reduction of the number of steps taken per day. Analysis of interaction effects also revealed that the effects of heat stress were equivalent across gender, age, and the region participants came from according to a World Health Organization classification scheme.Conclusions:Increased temperature and humidity are associated with a reduction in the number of steps taken per day. Community-based PA programs in hot hot/humid climates should consider novel approaches to increase PA levels.

scholarly journals Influence of Barn Climate, Body Postures and Milk Yield on the Respiration Rate of Dairy Cows

2019 ◽  
Vol 19 (2) ◽  
pp. 469-481 ◽  
Author(s):  
Severino Pinto ◽  
Gundula Hoffmann ◽  
Christian Ammon ◽  
Barbara Amon ◽  
Wolfgang Heuwieser ◽  
...  
Keyword(s):  
Heat Stress ◽  
Dairy Cows ◽  
Respiration Rate ◽  
Milk Yield ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Climatic Conditions ◽  
Related Factors ◽  
Body Postures ◽  
Daily Milk Yield

AbstractThe main objective of this study was to identify the influences of different climatic conditions and cow-related factors on the respiration rate (RR) of lactating dairy cows. Measurements were performed on 84 lactating Holstein Friesian dairy cows (first to eighth lactation) in Brandenburg, Germany. The RR was measured hourly or twice a day with up to three randomly chosen measurement days per week between 0700 h and 1500 h (GMT + 0100 h) by counting right thoraco-abdominal movements of the cows. Simultaneously with RR measurements, cow body postures (standing vs. lying) were documented. Cows’ milk yield and days in milk were recorded daily. The ambient temperature and relative humidity of the barn were recorded every 5 min to calculate the current temperature-humidity index (THI). The data were analyzed for interactions between THI and cow-related factors (body postures and daily milk yield) on RR using a repeated measurement linear mixed model. There was a significant effect of the interaction between current THI category and body postures on RR. The RRs of cows in lying posture in the THI < 68, 68 ≤ THI < 72 and 72 ≤ THI < 80 categories (37, 46 and 53 breaths per minute (bpm), respectively) were greater than those of standing cows in the same THI categories (30, 38 and 45 bpm, respectively). For each additional kilogram of milk produced daily, an increase of 0.23±0.19 bpm in RR was observed. Including cow-related factors may help to prevent uncertainties of RR in heat stress predictions. In practical application, these factors should be included when predicting RR to evaluate heat stress on dairy farms.

scholarly journals Effect of pruning, fertilization and pesticide injection on crown dieback in urban trees in Colombia: Analysis of factors involved

2019 ◽  
Vol 72 (2) ◽  
pp. 8883-8895
Author(s):  
Diana Lucia Giraldo-Charria ◽  
Flavio Humberto Moreno Hurtado ◽  
Juan Carlos Salazar-Uribe
Keyword(s):  
Wood Density ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Climatic Variability ◽  
Urban Trees ◽  
Initial State ◽  
Progressive Deterioration ◽  
Crown Dieback ◽  
Determinant Factor ◽  
Average Sample

This research evaluated the effect of pruning, fertilization and pesticide injection on crown dieback in urban trees in Colombia and analyzed the factors involved. Systemic insecticides and/or fungicides were applied through injections in the trunk of 15 tree species affected by the progressive deterioration of the crown in the urban forests of the Metropolitan Area of the Aburrá Valley. The presence of progressive deterioration was evaluated qualitatively on a scale from zero to three in an average sample of 12 individuals for each species. Two treatments were used: i) application of insecticide + fungicide, and ii) application of insecticide, both treatments were applied three times, plus a general treatment of pruning and fertilization. Also, two controls were evaluated: healthy trees and diseased trees without treatment. The probability of individual progressive deterioration (PD) during the study period according to the species, treatment applied, and the initial state of affectation was estimated using a generalized linear mixed model. The analysis of factors involved also included planting site, traffic flow of the site, the wood density of the species, and time. The results suggest that the deterioration is a dynamic phenomenon associated with environmental stresses caused mainly by the climatic variability. From the evaluated variables, the species seems to be the most determinant factor for the affectation, since intrinsic variables of the species, like wood density, can favor its appearance. On the contrary, the treatments evaluated did not affect the recovery of the species. The action of insects and pathogens seems to be opportunistic once trees are affected.

scholarly journals What Can We Learn from an Early Test on the Adaptation of Silver Fir Populations to Marginal Environments?

Forests ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 441 ◽  
Author(s):  
Marcin Klisz ◽  
Krzysztof Ukalski ◽  
Joanna Ukalska ◽  
Szymon Jastrzębowski ◽  
Radosław Puchałka ◽  
...  
Keyword(s):  
Mixed Model ◽  
Linear Mixed Model ◽  
Site Effect ◽  
Height Growth ◽  
Climatic Conditions ◽  
Silver Fir ◽  
Environment Interaction ◽  
Marginal Environments ◽  
The Stability ◽  
Marginal Environment

In order to determine the adaptive potential of silver fir in the southeast of Poland, the stability of the height of its five-year-old progeny was analyzed. The study was conducted in two different population groups in a total of four environments, including one ecologically marginal environment. The linear mixed model was used to evaluate the differentiation of populations in terms of height growth. The genotype and genotype-by-environment interaction biplot (GGE) were used to verify the stability of height. The climate of populations origin, in relation to actual fir distribution in Poland, was verified based on principal components analysis (PCA) of bioclimatic parameters. The highest total variability was explained by the genotype-environment interaction effect (GE) (54.50%), while the genotype effect (G) explained 41.27% and only 4.23% was explained by the site effect. The result of height growth variations revealed the Komańcza site as the most representative among study sites, while the Lesko site characterized the highest discriminating ability. The progeny occurring in climatic conditions most different from the average testing conditions showed a heterogeneous growth reaction, only adapting to the marginal environment, while the progeny of the second population in this region as well as the northernmost one was characterized by a mean but stable growth. The westernmost population revealed maladaptation. The assessment of the adaptability of silver fir depends on the broad spectrum of test conditions considering the ecologically marginal environments.

Analyzing discontinuities in longitudinal count data: A multilevel generalized linear mixed model.

2020 ◽  
Author(s):  
James L. Peugh ◽  
Sarah J. Beal ◽  
Meghan E. McGrady ◽  
Michael D. Toland ◽  
Constance Mara
Keyword(s):  
Count Data ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Generalized Linear Mixed Model ◽  
Longitudinal Count Data

Predicting bycatch hotspots based on suitable habitat derived from fishery-independent data

2020 ◽  
Vol 641 ◽  
pp. 159-175
Author(s):  
J Runnebaum ◽  
KR Tanaka ◽  
L Guan ◽  
J Cao ◽  
L O’Brien ◽  
...  
Keyword(s):  
Habitat Suitability ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Gulf Of Maine ◽  
Homarus Americanus ◽  
Management Tool ◽  
American Lobster ◽  
Suitable Habitat ◽  
Climate Conditions ◽  
Suitability Index

Bycatch remains a global problem in managing sustainable fisheries. A critical aspect of management is understanding the timing and spatial extent of bycatch. Fisheries management often relies on observed bycatch data, which are not always available due to a lack of reporting or observer coverage. Alternatively, analyzing the overlap in suitable habitat for the target and non-target species can provide a spatial management tool to understand where bycatch interactions are likely to occur. Potential bycatch hotspots based on suitable habitat were predicted for cusk Brosme brosme incidentally caught in the Gulf of Maine American lobster Homarus americanus fishery. Data from multiple fisheries-independent surveys were combined in a delta-generalized linear mixed model to generate spatially explicit density estimates for use in an independent habitat suitability index. The habitat suitability indices for American lobster and cusk were then compared to predict potential bycatch hotspot locations. Suitable habitat for American lobster has increased between 1980 and 2013 while suitable habitat for cusk decreased throughout most of the Gulf of Maine, except for Georges Basin and the Great South Channel. The proportion of overlap in suitable habitat varied interannually but decreased slightly in the spring and remained relatively stable in the fall over the time series. As Gulf of Maine temperatures continue to increase, the interactions between American lobster and cusk are predicted to decline as cusk habitat continues to constrict. This framework can contribute to fisheries managers’ understanding of changes in habitat overlap as climate conditions continue to change and alter where bycatch interactions could occur.

Long-term seizure outcomes after pediatric temporal lobectomy: does brain MRI lesion matter?

2019 ◽  
Vol 24 (2) ◽  
pp. 200-208
Author(s):  
Ravindra Arya ◽  
Francesco T. Mangano ◽  
Paul S. Horn ◽  
Sabrina K. Kaul ◽  
Serena K. Kaul ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Hippocampal Sclerosis ◽  
Brain Mri ◽  
Temporal Lobectomy ◽  
Seizure Freedom ◽  
Seizure Onset

OBJECTIVEThere is emerging data that adults with temporal lobe epilepsy (TLE) without a discrete lesion on brain MRI have surgical outcomes comparable to those with hippocampal sclerosis (HS). However, pediatric TLE is different from its adult counterpart. In this study, the authors investigated if the presence of a potentially epileptogenic lesion on presurgical brain MRI influences the long-term seizure outcomes after pediatric temporal lobectomy.METHODSChildren who underwent temporal lobectomy between 2007 and 2015 and had at least 1 year of seizure outcomes data were identified. These were classified into lesional and MRI-negative groups based on whether an epilepsy-protocol brain MRI showed a lesion sufficiently specific to guide surgical decisions. These patients were also categorized into pure TLE and temporal plus epilepsies based on the neurophysiological localization of the seizure-onset zone. Seizure outcomes at each follow-up visit were incorporated into a repeated-measures generalized linear mixed model (GLMM) with MRI status as a grouping variable. Clinical variables were incorporated into GLMM as covariates.RESULTSOne hundred nine patients (44 females) were included, aged 5 to 21 years, and were classified as lesional (73%), MRI negative (27%), pure TLE (56%), and temporal plus (44%). After a mean follow-up of 3.2 years (range 1.2–8.8 years), 66% of the patients were seizure free for ≥ 1 year at last follow-up. GLMM analysis revealed that lesional patients were more likely to be seizure free over the long term compared to MRI-negative patients for the overall cohort (OR 2.58, p < 0.0001) and for temporal plus epilepsies (OR 1.85, p = 0.0052). The effect of MRI lesion was not significant for pure TLE (OR 2.64, p = 0.0635). Concordance of ictal electroencephalography (OR 3.46, p < 0.0001), magnetoencephalography (OR 4.26, p < 0.0001), and later age of seizure onset (OR 1.05, p = 0.0091) were associated with a higher likelihood of seizure freedom. The most common histological findings included cortical dysplasia types 1B and 2A, HS (40% with dual pathology), and tuberous sclerosis.CONCLUSIONSA lesion on presurgical brain MRI is an important determinant of long-term seizure freedom after pediatric temporal lobectomy. Pediatric TLE is heterogeneous regarding etiologies and organization of seizure-onset zones with many patients qualifying for temporal plus nosology. The presence of an MRI lesion determined seizure outcomes in patients with temporal plus epilepsies. However, pure TLE had comparable surgical seizure outcomes for lesional and MRI-negative groups.

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