Because of its agronomic benefits, farm-scale composting is an efficient means of recycling agricultural waste. Composting process is an aerobic degradation of fresh organic matter in mature compost. ...Nevertheless, according to the literature, composting may induce some environmental problems. The environmental impacts of composting will be described, along with an assessment of farm-scale composting practices which play a major role in pollution. The main environmental components potentially affected by composting pollution are air and water. Various gases released by composting, such as NH sub(3), CH sub(4) and N sub(2)O, can impact air quality and are therefore studied because they all have environmental impacts and can be controlled by composting management. The effect on water quality can be evaluated by considering loss of NO sub(3) super(-), NH sub(4) super(+), organic compounds and PO sub(4) super(3-). Technical evaluation criteria for the impact of farm-scale composting on the air are determined from the physical and chemical characteristics of the raw materials, the use of additives, the turning method and frequency and the duration of the composting operations. Regarding water, the weather conditions at the beginning of the composting operation, the location of the heap, the protection against rain, the water addition during the process, the use of covers and the recovery of leaching and runoff water are also taken into account. The two main practices which control the air and water pollution from composting are: the choice of the raw material which influences gas emissions and the choice of composting location which have an high effect on losses by leaching and runoff.
The separate design concepts of dual-mobility cups and triple-taper femoral stems were developed to improve survivorship following total hip replacement (THR) by reducing instability/dislocation and ...enabling enhanced fixation. Successful outcomes at over two decades have been reported with earlier-generation devices based on these concepts. The current study aimed to provide the first long-term results with a unique pairing of later-generation dual-mobility cup and triple-taper cementless femoral stem after a decade of use in patients undergoing THR.
In this retrospective analysis, records were reviewed for all subjects implanted with this dual-mobility cup/cementless femoral stem combination at three centers between 2002 and 2005. Any subject who had not already had follow-up visit beyond 10 years, was not previously revised, and still living were invited for a single follow-up visit consisting of Merle d'Aubgine Scores, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index, and standard radiographs.
There were 244 THRs available for analysis. At a mean follow-up of 11.9 years, the Kaplan-Meier survivorship (endpoint: revision for any reason) was 99.1% (95% CI, 97.6-99.7) for the stem and 95.9% (95% CI, 93.1-97.6) for the cup. Merle d'Aubigne Scores were significantly improved from baseline and WOMAC scores were in the satisfactory range at the final follow-up. Radiographic analysis revealed no cases of stem subsidence, no cases of bone hypertrophy, 1 (0.4%) case of bone atrophy, and 3 (1.2%) cases of osteolysis around the stem. No subjects had radiolucent lines greater than 1 mm in any femoral Gruen zone. Evidence of cup migration was seen in 1 (0.4%) subject and 1 (0.4%) subject had evidence of osteolysis that was seen in Gruen zones I, II, IV, and V.
This combination of a later-generation dual-mobility cup and cementless triple-taper stem was associated with excellent survivorship and satisfactory functional outcomes at over 10 years follow-up.
ClinicalTrials.gov, NCT02648152. Date of registration: January 6, 2016. Retrospectively registered.
Five independent multicentury reconstructions of the July Canadian Drought Code and one reconstruction of the mean July–August temperature were developed using a network of 120 well-replicated ...tree-ring chronologies covering the area of the eastern Boreal Plains to the eastern Boreal Shield of Canada. The reconstructions were performed using 54 time-varying reconstruction submodels that explained up to 50% of the regional drought variance during the period of 1919–84. Spatial correlation fields on the six reconstructions revealed that the meridional component of the climate system from central to eastern Canada increased since the mid–nineteenth century. The most obvious change was observed in the decadal scale of variability. Using 500-hPa geopotential height and wind composites, this zonal to meridional transition was interpreted as a response to an amplification of long waves flowing over the eastern North Pacific into boreal Canada, from approximately 1851 to 1940. Composites with NOAA Extended Reconstructed SSTs indicated a coupling between the meridional component and tropical and North Pacific SST for a period covering at least the past 150 yr, supporting previous findings of a summertime global ocean–atmosphere–land surface coupling. This change in the global atmospheric circulation could be a key element toward understanding the observed temporal changes in the Canadian boreal forest fire regimes over the past 150 yr.
This paper investigates the influence of surface climate and atmospheric circulation on radial growth of eight boreal tree species growing in the Duck Mountain Provincial Forest, Manitoba, Canada. ...Tree-ring residual chronologies were built, transformed into principal components (PCs), and analysed through correlation and response functions to reveal their associations to climate (temperature, precipitation, and drought data for the period 1912-1999, as well as local geopotential height data for the period 1948-1999). Geopotential height correlation and composite charts for the Northern Hemisphere were also constructed. Correlation and response function coefficients indicated that radial growth of all species was negatively affected by temperature-induced drought stresses from the summers previous and current to ring formation. The summer drought stress alone explained nearly 28% of the variance in PC1. Warm spring temperature was also a positive factor for Pinus banksiana Lamb. and Picea glauca (Moench) Voss, but a negative one for all hardwoods. Analyses performed on geopotential height highlighted the importance of the Northern Hemispheric atmospheric circulation in the species' response to climate. The variability within the 500-hPa level over southern Manitoba explained 39% and 58% of the variability in PC1 and PC2, respectively. The relationships were highly significant with the middle and high troposphere during spring and late summer (determinant factor for growing season length) and with the troposphere and stratosphere during summer. The sensitivity of tree growth to atmospheric circulation exceeded the synoptic scale, with a response associated with yearly variations in the amplitude of the mid-tropospheric longwaves.
Trends and periodicities in summer drought severity are investigated on a network of Canadian Drought Code (CDC) monthly average indices extending from central Quebec to western Manitoba and covering ...the instrumental period 1913-1998. The relationship and coherency between CDC indices and ocean-atmosphere circulation patterns are also examined. Trend analyses indicate that drought severity is unchanged in eastern and central Canada. Composite analyses indicate that for most of the corridor, severe drought seasons occur with a combination of positive 500-hPa geopotential height anomalies centered over the Gulf of Alaska and over the Baffin Bay. Additional severe drought seasons develop across the corridor in the presence of positive height anomalies located over or upstream of the affected regions. According to spectral analyses, the North Atlantic and the North Pacific circulation patterns modulate the drought variability at the decadal scale. Our results lead us to conclude that climate warming and the increases in the amount and frequency of precipitation in eastern Canada during the last century had no significant impact on summer drought severity. It is unlikely that linear climate change contributed to the change in the boreal forest dynamics observed over the past 150 years.
Alkaloids from meadow saffron seeds are used in numerous medicines. Variations of seed alkaloid content (colchicine and colchicoside) were observed between natural sites. Nevertheless, this character ...remained stable when these accessions (corms collected on different natural sites) were cultivated in a same field. A relation between soil properties and seeds alkaloid content can be expected. Soil analyses were performed in three soil layers (0–30, 30–60, 60–90
cm) on three meadow saffron natural sites and two cultivated sites. Linear regressions were performed between 20 soil factors, analysed in the three soil layers and the seed alkaloid content. Cobalt and calcium soil contents were positively correlated with seed alkaloid content. The coefficients of determination (
R
2) were the highest in the 30–60
cm soil layer, respectively, of 0.85 and 0.74. Mineral analyses were performed on seed. In spite of the important difference of level, linear relations were observed between the sum of Ca and 1000 × Co contents (Ca + Co) in seeds and in soil (
R
2 = 0.76). A highly significant relation was shown between (Ca + Co) in seeds and alkaloid content (
R
2 = 0.96) showing for the first time on
Colchicum autumnale the positive influence of these mineral elements on the alkaloid synthesis. Soil and foliar supplies of Ca and Co could be tested to improve seed alkaloid content.
Tree-ring chronologies for tamarack (Larix laricina (Du Roi) K. Koch) growing in four stand types covering a dry-to-wet gradient were developed to investigate the association between radial growth ...and climate as well as evidence of larch sawfly (Pristiphora erichsonii Hartig) herbivory near Churchill, subarctic Manitoba. The chronologies, produced using both living and subfossil material, were well replicated for the period 1800 to 2000. Our results indicated that climate explained more than 60% of the growth variation in tamarack with temperature from May to July of the growing season being most important. This was unusual considering that other studies showed a weak radial growth-climate association in tamarack because of signal contamination due to severe larch sawfly defoliation. Potential outbreak episodes were investigated by looking at pointer years and by contrasting the variance within the tamarack tree-ring series with that observed in climate and in nonhost species. A weak correspondence was observed among pale latewood rings, growth suppression period, and incomplete rings. Comparison of host and nonhost chronologies revealed synchronized growth suppression periods in tamarack during 1818–1824, 1857–1864, 1891–1892, 1903–1912, and 1959–1964, with seldom more than 25% of the trees being affected. The 20th-century suppressions corresponded to known outbreaks identified in Manitoba. However, they also corresponded to periods of little residues in the climate model suggesting that they may be due to short-term changes in site hydrology. This study stresses the difficulties to use dendrochronology to identify what may be low severity or “subepidemic” defoliation events. It also stresses the potential differences in the larch sawfly dynamics between the boreal forest and the forest-tundra. Further studies using an extended network of chronologies will be needed to decipher the short-term impacts of climate from those of low severity defoliation episodes.
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