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1.
J Environ Manage ; 350: 119637, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38000274

ABSTRACT

Woodchips in stand-off pads for wintering cows have been applied in countries like Ireland and New Zealand. Their primary role is to protect soils by effectively filtering nutrients during wet conditions, while ensuring a healthy and comfortable environment for the cows. The stand-off pad concept has the potential to be adopted in Canada to provide year-long outdoor access to tie-stall dairy cows. The objective of this study was to evaluate the effect of alternative filtering materials and bed aeration under controlled laboratory conditions. Twelve biofilter columns (0.3 m in diameter and 1-m high) were installed in 12 environmentally-controlled chambers (1.2-m wide by 2.4-m long), and divided into four treatments: a bed of conventional woodchips or an alternative mix of organic materials (sphagnum peat moss, woodchips and biochar) with and without aeration (flux rate set at 0.6 m3/min/m2). Approximately 0.6 L of semi-synthetic dairy manure and 1 L of tap water were poured on the biofilters during two experimental periods of 4 weeks, simulating the effect of either winter or summer conditions (room temperature below or over 10 °C) on the retention of nutrients and fecal bacteria. Results showed that the alternative biofilters under both summer and winter conditions were more efficient in removing COD, SS, TN, and NO3-N than conventional biofilters (maximum efficiencies of 97.6%, 99.7%, 96.4%, and 98.4%, respectively). Similarly for E. coli, they achieved a minimum concentration of 1.8 Log10 CFU/100 ml. Conventional biofilters were more efficient for PO4-P removal with a maximum efficiency of 88.2%. Aeration did not have any significant effect under the tested temperature conditions. Additional factors such as media adaptation time as well as aeration flow during this period should be considered.


Subject(s)
Escherichia coli , Manure , Female , Animals , Cattle , Temperature , Feces , Nutrients , Filtration/methods
2.
J Environ Manage ; 348: 119306, 2023 Dec 15.
Article in English | MEDLINE | ID: mdl-37839204

ABSTRACT

Research studies on nutrient content and microbial communities after the application of organic manure have been reported, while available information about multi-interaction mechanisms of nutrient stoichiometry and microbial succession in soil aggregates remains limited. This work conducted a 10-year field experiment amended with cow manure (1.5 t/ha), during which the application of organic manure stimulated the fragmentation of soil macro-aggregates (>5 mm) and the agglomeration of soil micro-aggregates (<0.25 mm). Hence, the proportion of medium-size aggregates (0.25-5 mm) was increased in bulk soil, and there was an insignificant difference in the stability of soil aggregates. Meanwhile, the application of organic manure increased soil organic carbon (SOC), total nitrogen (TN) and phosphorus (TP) in all soil aggregate fractions. SOC, TN and TP were higher in micro-aggregates (<0.25 mm) after the application of organic manure, thus the dominating phylum of bacteria and fungi was more abundance in micro-aggregates due to the increase in nutrient level. During the organic fertilization process, fungal communities significantly changed because the variation of carbon-to-nitrogen ratio (C:N) in soil aggregates. Cultivated farmland in Northeast China showed a considerable capacity to sequestrate SOC during the organic fertilization process, but nitrogen may be a primary macro-element limiting soil productivity. Theoretically, organic manure amended with nitrogen fertilizer could be an effective measure to maintain microbial diversity and crop productivity in agro-ecosystems in Northeast China.


Subject(s)
Microbiota , Soil , Carbon/analysis , Manure , Fertilizers/analysis , Nitrogen/analysis , China , Fertilization , Soil Microbiology , Agriculture
3.
Environ Manage ; 71(2): 365-378, 2023 02.
Article in English | MEDLINE | ID: mdl-36510028

ABSTRACT

How much wetland we should protect or restore is not a simple question, such that conservation targets are often set according to political agendas, then standardized globally. However, given their key regulating hydrological functions, wetlands represent nature-based solutions to the anticipated, exacerbating effect of climate change on drought and flood events, which will vary at the regional scale. Here, we propose a science-based approach to establishing regional wetland restoration targets centered on their hydrological functions, using a case study on several sub-watersheds of a northern temperate basin in south-eastern Canada. We posit that restoration targets should minimally mitigate the negative effects of climate change on watershed hydrology, namely peak and low flows. We used a semi-distributed hydrological model, HYDROTEL, to perform a hydroclimatic assessment, including 47 climate projections over the 1979-2099 period, to test the effect of wetland restoration scenarios on peak and low flows. The results showed that hydrological responses to climate change varied among sub-watersheds (even at the scale of a relatively small region), and that, to mitigate these changes, increases in wetland coverage should be between 20% and up to 150%. At low restoration levels, increasing wetland coverage was more effective in attenuating floods than alleviating droughts. This study indicates that a no-net-loss policy is insufficient to maintain current hydrological cycles in the face of climate change; rather, a 'net gain' in wetland cover is needed.


Subject(s)
Climate Change , Conservation of Natural Resources , Wetlands , Canada , Droughts , Hydrology
4.
Environ Monit Assess ; 195(10): 1198, 2023 Sep 12.
Article in English | MEDLINE | ID: mdl-37698733

ABSTRACT

A 3D hydrodynamic model (EFDC) was applied to simulate dissolved oxygen (DO) and temperature (T) (two crucial parameters impacting water quality) throughout Lake St. Charles, a rural-urban shallow lake located North of Quebec City, Canada. Model outputs of T and DO corroborate observations at five monitoring stations within the lake. Simulated results indicated annual cycles of turnovers and stratifications and different behaviors for the deep and shallow basins. For the simulated years, the deep basin was stratified in summer and winter, while the shallow basin was mostly mixed throughout the year. The lake heat budget indicates that during summer with a long retention time, the thermal structure of the lake is principally controlled by net radiation, latent, and sensible heat fluxes. For the rest of the year, the inflow (from the main tributary, the Des Hurons River) and outflow are the main drivers of the lake's thermal structure.


Subject(s)
Hydrodynamics , Lakes , Temperature , Environmental Monitoring , Oxygen
5.
J Environ Manage ; 234: 448-457, 2019 Mar 15.
Article in English | MEDLINE | ID: mdl-30640170

ABSTRACT

Conversion of wetlands into other land covers such as cropland or urban area can affect watershed hydrology. The main objective of this work was to quantify the impact of land cover changes, especially those for wetlands, on low flow support and high flow attenuation, through a sub-watershed analysis of the St. Charles River, Quebec, Canada. 1978 and 2014 land cover scenarios, depicting a decrease in wetland areas of 15% at the watershed scale, were integrated into the hydrological modelling platform PHYSITEL/HYDROTEL. The most sensitive model parameters were automatically calibrated at the sub-watershed scale using the dynamically dimensioned search (DDS) algorithm. Pairs of simulations (with and without wetlands) were generated and model outputs were compared to illustrate the differences between the hydrological services provided by the wetlands of the 1978 land cover scenario and those provided by the wetlands of the 2014 land cover scenario. Results showed that low flow support at the outlet of the watershed, in scenarios with wetlands, compared to without wetland, would have increased from 2 to 14% in the 1978 land cover scenario (depending on flow indicator) and from 3 to 20% given the 2014 land cover scenario, whereas high flow attenuation would have been reduced from 15-26% to 16-20%, respectively. Results showed that the effect of wetland change was different between sub-watersheds, but demonstrated that the loss of wetland areas generally leads to a loss of hydrological services and highlighted the need for wetland conservation programs and restoration actions.


Subject(s)
Models, Theoretical , Wetlands , Canada , Hydrology , Quebec
6.
J Environ Manage ; 127: 150-61, 2013 Sep 30.
Article in English | MEDLINE | ID: mdl-23702377

ABSTRACT

Toxoplasma gondii (T. gondii) is a zoonotic protozoan that sometimes causes serious illness in humans and other animals worldwide, including the Canadian Arctic. Wild and domestic felids, the only hosts able to shed T. gondii oocysts, are practically non-existent in the Canadian Arctic. So here the hypothesis that T. gondii oocysts, shed in the southern areas of the boreal watershed, could contaminate the Arctic coastal marine environment via surface runoff, particularly during the spring snowmelt period, was explored. A watershed model was applied to simulate the hydrological transport of T. gondii oocysts during the snowmelt period and test the possible efficiency of river-to-sea transport as a potential source of marine organisms' exposure to this pathogen. Simulations were run for two pilot watersheds with the ultimate aim of extrapolating the results across the Canadian Arctic watersheds. Results suggest that daily stream flow concentrations of T. gondii oocysts at the river outlet are likely to be very low. However, accumulation of oocysts in the estuarine areas may be large enough to contaminate estuarine/marine filter-feeding molluscs and snails on which seals and other marine mammals may feed. Potential maximum concentrations of T. gondii oocysts in runoff are reached at the beginning of the snowmelt period with maxima varying with discharge rates into rivers and how far upstream oocysts are discharged. Meteorological conditions during the snowmelt period can affect simulated concentrations of oocysts. These findings support the hypothesis that T. gondii oocysts carried in snowmelt runoff could be a source of T. gondii infection for marine mammals in the Canadian Arctic, and for Arctic human populations that hunt and consume raw meat from marine mammals.


Subject(s)
Disease Reservoirs/parasitology , Oocysts/physiology , Toxoplasma/physiology , Water/parasitology , Animals , Aquatic Organisms/parasitology , Arctic Regions , Canada , Computer Simulation , Humans , Snow/parasitology , Water Movements
7.
Protein Sci ; 32(11): e4791, 2023 11.
Article in English | MEDLINE | ID: mdl-37801623

ABSTRACT

Caveolin-1 is an integral membrane protein that is known to acquire a number of posttranslational modifications upon trafficking to the plasma membrane. In particular, caveolin-1 is palmitoylated at three cysteine residues (C133, C143, and C156) located within the C-terminal domain of the protein which could have structural and topological implications. Herein, a reliable preparation of full-length S-alkylated caveolin-1, which closely mimics the palmitoylation observed in vivo, is described. HPLC and ESI-LC-MS analyses verified the addition of the C16 alkyl groups to caveolin-1 constructs containing one (C133), two (C133 and C143), and three (C133, C143, and C156) cysteine residues. Circular dichroism spectroscopy analysis of the constructs revealed that S-alkylation does not significantly affect the global helicity of the protein; however, molecular dynamics simulations revealed that there were local regions where the helicity was altered positively or negatively by S-alkylation. In addition, the simulations showed that lipidation tames the topological promiscuity of the C-terminal domain, resulting in a disposition within the bilayer characterized by increased depth.


Subject(s)
Caveolin 1 , Cysteine , Caveolin 1/genetics , Caveolin 1/chemistry , Caveolin 1/metabolism , Cysteine/metabolism , Membrane Proteins/chemistry , Cell Membrane/metabolism , Alkylation
8.
Ophthalmology ; 119(8): 1590-5, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22683062

ABSTRACT

OBJECTIVE: To study the relevance of liver function test (LFT) results for early detection of liver metastasis of uveal melanoma. DESIGN: Evaluation of diagnostic test. PARTICIPANTS: Eighty-eight patients were included in whom metastasis developed while undergoing semiannual follow-up with LFTs, including aspartate-aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (γGT), lactate dehydrogenase (LDH), and phosphatase alkaline (PA). As controls, 174 patients with uveal melanoma without metastasis were included. METHODS: The diagnostic attributes of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each test were estimated from cross-tabulation tables of test results according to the diagnosis of metastasis. The proportions of false-positive results between groups of patients with and without metastasis were compared in log-binomial regression models. MAIN OUTCOME MEASURES: Sensitivity, specificity, PPV, NPV, and cost evaluation. RESULTS: Metastases were detected after LFT abnormality (at least 1 abnormal test result) in 40 (45%) patients. The overall sensitivity of LFTs ranged from 12.5% to 58.0%, and the PPV ranged from 9.4% to 38.6%. The overall specificity and NPV were 90% or greater. The proportions of false-positive results between groups of patients with and without metastasis did not differ significantly (all P≥0.38). Using a cost evaluation, semi-annual screening by LFTs was calculated to cost $35.5/year per patient, including liver imaging induced by true and false-positive results. CONCLUSIONS: Isolated or combined LFTs for AST, ALT, γGT, LDH, and PA are not helpful for detection of early metastasis. However, the high NPVs suggest that LFT screening can allow clinicians to reassure the patient when the LFT results are negative.


Subject(s)
Liver Function Tests , Liver Neoplasms/diagnosis , Melanoma/diagnosis , Uveal Neoplasms/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Alanine Transaminase/blood , Alkaline Phosphatase/blood , Aspartate Aminotransferases/blood , Biomarkers/blood , Early Detection of Cancer , False Positive Reactions , Female , Humans , L-Lactate Dehydrogenase/blood , Liver Function Tests/economics , Liver Neoplasms/enzymology , Liver Neoplasms/secondary , Male , Melanoma/enzymology , Melanoma/secondary , Middle Aged , Predictive Value of Tests , Sensitivity and Specificity , Young Adult , gamma-Glutamyltransferase/blood
9.
J Environ Qual ; 41(5): 1402-12, 2012.
Article in English | MEDLINE | ID: mdl-23099931

ABSTRACT

Phosphorus (P) use in excess of crop needs may impact surface water quality and contribute to eutrophication. However, P loss from agricultural land to water has never been estimated at the Canadian national scale. In this paper, the risk of P desorption from Canadian agricultural land is assessed by the source component of the indicator of risk of water contamination by P (IROWC-P). The IROWC-P source component (P_source) characterized the mobilization potential of soluble P and integrated four models of P desorption by water for dominant agricultural soil series of Canada on the soil landscape of Canada polygon scale (1:1,000,000). The objective of our study was to describe and evaluate a standardized method for deriving the P_source component. The P_source was assessed over 5-yr intervals from 1981 to 2006 for scientifically based knowledge by relating annual P balance values, soil test P (STP) analyses, soil P saturation index, and Self-Davis water extractable P extraction values. Results show trends of soil P enrichment for most Canadian provinces over the 25-yr period but also an increased percentage of farmland classified above the water extractable soil P environmental threshold of 4 mg P kg. The Canadian Prairies and Ontario showed small P_source values and almost no farmland above the environmental threshold. Quebec and the Atlantic Provinces had P_source values that exceeded the environmental threshold in 2006; more than 33% of farmland is classified above the environmental threshold value.


Subject(s)
Agriculture/trends , Phosphorus/analysis , Soil/analysis , Water Pollution, Chemical/analysis , Canada , Geography
10.
J Environ Qual ; 41(1): 52-63, 2012.
Article in English | MEDLINE | ID: mdl-22218173

ABSTRACT

This paper proposes a hydrological modeling framework to define achievable performance standards (APSs) for pesticides that could be attained after implementation of recommended management actions, agricultural practices, and available technologies (i.e., beneficial management practices [BMPs]). An integrated hydrological modeling system, Gestion Intégrée des Bassins versants à l'aide d'un Système Informatisé, was used to quantify APSs for six Canadian watersheds for eight pesticides: atrazine, carbofuran, dicamba, glyphosate, MCPB, MCPA, metolachlor, and 2,4-D. Outputs from simulation runs to predict pesticide concentration under current conditions and in response to implementation of two types of beneficial management practices (reduced pesticide application rate and 1- to 10-m-wide edge-of-field and/or riparian buffer strips, implemented singly or in combination) showed that APS values for scenarios with BMPs were less than those for current conditions. Moreover, APS values at the outlet of watersheds were usually less than ecological thresholds of good condition, when available. Upstream river reaches were at greater risk of having concentrations above a given ecological thresholds because of limited stream flows and overland loads of pesticides. Our integrated approach of "hydrological modeling-APS estimation-ecotoxicological significance" provides the most effective interpretation possible, for management and education purposes, of the potential biological impact of predicted pesticide concentrations in rivers.


Subject(s)
Environmental Monitoring/standards , Models, Theoretical , Pesticides/chemistry , Water Pollutants, Chemical/chemistry , Water Pollution, Chemical/prevention & control , Canada , Computer Simulation , Ecosystem , Environmental Monitoring/methods , Time Factors , Water Movements
11.
Mol Vis ; 17: 1324-33, 2011.
Article in English | MEDLINE | ID: mdl-21647268

ABSTRACT

PURPOSE: Uveal melanoma (UM) is the most common primary cancer of the eye, resulting not only in vision loss, but also in metastatic death. This study attempts to identify changes in the patterns of gene expression that lead to malignant transformation and proliferation of normal uveal melanocytes (UVM) using the Suppressive Subtractive Hybridization (SSH) technique. METHODS: The SSH technique was used to isolate genes that are differentially expressed in the TP31 cell line derived from a primary UM compared to UVM. The expression level of selected genes was further validated by microarray, semi-quantitative RT-PCR and western blot analyses. RESULTS: Analysis of the subtracted libraries revealed that 37 and 36 genes were, respectively, up- and downregulated in TP31 cells compared to UVM. Differential expression of the majority of these genes was confirmed by comparing UM cells with UVM by microarray. The expression pattern of selected genes was analyzed by semi-quantitative RT-PCR and western blot, and was found to be consistent with the SSH findings. CONCLUSIONS: We demonstrated that the SSH technique is efficient to detect differentially expressed genes in UM. The genes identified in this study represent valuable candidates for further functional analysis in UM and should be informative in studying the biology of this tumor.


Subject(s)
Comparative Genomic Hybridization/methods , Eye/pathology , Gene Expression Regulation, Neoplastic , Genes, Neoplasm , Melanocytes/metabolism , Melanoma , Uveal Neoplasms , Adult , Aged , Blotting, Western , Cell Culture Techniques , Cell Line, Tumor , Down-Regulation , Eye/metabolism , Female , Gene Expression Profiling , Humans , Melanoma/genetics , Melanoma/pathology , Middle Aged , Oligonucleotide Array Sequence Analysis , RNA, Messenger/analysis , RNA, Messenger/biosynthesis , Reverse Transcriptase Polymerase Chain Reaction , Up-Regulation , Uveal Neoplasms/genetics , Uveal Neoplasms/pathology
12.
Animals (Basel) ; 11(1)2020 Dec 24.
Article in English | MEDLINE | ID: mdl-33374226

ABSTRACT

Animal welfare concerns have been a challenging issue for producers and international marketing. In laying hen production, cage-free systems (CFS) have been identified as an alternative to ensure the laying hens' well-being. Nevertheless, in CFS, important environmental issues have been reported, decreasing indoor air quality. Environmental control strategies (ECS) have been designed to enhance indoor air quality in CFSs. However, little information exists about the effect of these ECSs on natural animal behaviors. Four strategies and one control were tested in an experimental CFS, previously designed to track behavioral variables using video recordings over seven time-lapses of 1 hour per day. Spatial occupancy (SO) and laying hen behaviors (LHB) were registered. One statistical analysis was applied to evaluate the effect of ECS on SO and LHB using a multinomial response model. Results show lower chances to use litter area within the reduction of litter allowance treatment (T17) (p < 0.05). Neither the four ECSs nor the control implemented in this experiment affected the natural behaviors of the hens. However, stress patterns and high activity were reported in the T17 treatment. This study shows that it is possible to use these ECSs without disrupting laying hens' natural behaviors.

13.
J Environ Qual ; 38(5): 2096-105, 2009.
Article in English | MEDLINE | ID: mdl-19704152

ABSTRACT

Many phosphorus (P) risk indicators have been developed to assess the risk of P loss from agricultural land to surface water. Most of these indicators are designed for land and climates where rainfall-induced erosion of particulate P from sloping landscapes is the main process of P transport. No indicators have been validated in the Canadian Prairies, where P losses are driven by snowmelt-driven runoff over nearly level landscapes and frozen soils. The objective of this project was to evaluate the relationship between water quality data for P from 14 watersheds and three existing P risk indicators for their potential use in the southern Manitoba prairie region of Canada. None of the indicators, including Birr and Mulla's P Index, a preliminary P risk indicator for Manitoba, and a preliminary version of Canada's National Indicator of Risk of Water Contamination by Phosphorus, was significantly correlated with mean concentrations of total P in water or P export per hectare. Although erosion risk was a significant factor influencing the value of these indexes, erosion risk was not correlated with either measure of P loss in these watersheds. Several other watershed characteristics, including average soil test P concentrations, livestock density, proportion of land in annual crops, and the land's inherent capability for agricultural production, were strongly correlated with P concentrations in water (r = 0.80***, r = 0.63**, 0.76***, and -0.70**, respectively). Therefore, these types of P risk indicators require modifications to estimate the risk of P loss under the soil, landscape, and climatic conditions of southern Manitoba.


Subject(s)
Phosphorus/analysis , Water Pollution/analysis , Water/chemistry , Manitoba , Risk Assessment , Water Supply
14.
Sci Rep ; 9(1): 4400, 2019 03 13.
Article in English | MEDLINE | ID: mdl-30867512

ABSTRACT

The world demand for phosphate has gradually increased over the last decades, currently achieving alarming levels considering available rock reserves. The use of soil microorganisms, such as arbuscular mycorrhizal fungi (AMF), has been suggested as a promising alternative to improve phosphorus-use efficiency. However, the effect of the source of phosphorus on the interactions within the soil microbial community remains unclear. Here, we evaluated the links between the total dry matter content of sugarcane and the interactions within the soil microbial community under different phosphate sources, with/without AMF inoculation. The phosphate sources were Simple Superphosphate (SS, 18% of P2O5), Catalão rock phosphate (CA, 2.93% of P2O5) and Bayovar rock phosphate (BA, 14% of P2O5). The results indicated that the BA source led to the largest total dry matter content. The phosphate source affected total dry matter and the structure of the soil microbial communities. The bacterial interactions increased across sources with high percentage of P2O5, while the fungal interactions decreased. The interactions between bacterial and fungal microorganisms allowed to identify the percentage of P2O5 resulting in the highest total sugarcane dry matter. Our findings suggested the soil microbial interactions as a potential microbial indicator helping to improve the agricultural management.


Subject(s)
Phosphorus/chemistry , Saccharum/growth & development , Saccharum/microbiology , Diphosphates/chemistry , Soil/chemistry , Soil Microbiology
15.
Integr Environ Assess Manag ; 12(3): 559-71, 2016 Jul.
Article in English | MEDLINE | ID: mdl-26331624

ABSTRACT

Pesticide transport by surface runoff depends on climate, agricultural practices, topography, soil characteristics, crop type, and pest phenology. To accurately assess the impact of climate change, these factors must be accounted for in a single framework by integrating their interaction and uncertainty. This article presents the development and application of a framework to assess the impact of climate change on pesticide transport by surface runoff in southern Québec (Canada) for the 1981-2040 period. The crop enemies investigated were: weeds for corn (Zea mays); and for apple orchard (Malus pumila), 3 insect pests (codling moth [Cydia pomonella], plum curculio [Conotrachelus nenuphar], and apple maggot [Rhagoletis pomonella]), 2 diseases (apple scab [Venturia inaequalis], and fire blight [Erwinia amylovora]). A total of 23 climate simulations, 19 sites, and 11 active ingredients were considered. The relationship between climate and phenology was accounted for by bioclimatic models of the Computer Centre for Agricultural Pest Forecasting (CIPRA) software. Exported loads of pesticides were evaluated at the edge-of-field scale using the Pesticide Root Zone Model (PRZM), simulating both hydrology and chemical transport. A stochastic model was developed to account for PRZM parameter uncertainty. Results of this study indicate that for the 2011-2040 period, application dates would be advanced from 3 to 7 days on average with respect to the 1981-2010 period. However, the impact of climate change on maximum daily rainfall during the application window is not statistically significant, mainly due to the high variability of extreme rainfall events. Hence, for the studied sites and crop enemies considered, climate change impact on pesticide transported in surface runoff is not statistically significant throughout the 2011-2040 period. Integr Environ Assess Managem 2016;12:559-571. © Her Majesty the Queen in Right of Canada 2015; Published 2015 SETAC.


Subject(s)
Climate Change , Environmental Monitoring/methods , Pesticides/analysis , Water Pollutants, Chemical/analysis , Agriculture , Canada , Malus , Water Movements , Water Pollution, Chemical/statistics & numerical data , Zea mays
16.
PLoS One ; 11(3): e0152313, 2016.
Article in English | MEDLINE | ID: mdl-27031339

ABSTRACT

Micro-basin tillage is a soil and water conservation practice that requires building individual earth blocks along furrows. In this study, plot experiments were conducted to assess the efficiency of micro-basin tillage on sloping croplands between 2012 and 2013 (5°and 7°). The conceptual, optimal, block interval model was used to design micro-basins which are meant to capture the maximum amount of water per unit area. Results indicated that when compared to the up-down slope tillage, micro-basin tillage could increase soil water content and maize yield by about 45% and 17%, and reduce runoff, sediment and nutrients loads by about 63%, 96% and 86%, respectively. Meanwhile, micro-basin tillage could reduce the peak runoff rates and delay the initial runoff-yielding time. In addition, micro-basin tillage with the optimal block interval proved to be the best one among all treatments with different intervals. Compared with treatments of other block intervals, the optimal block interval treatments increased soil moisture by around 10% and reduced runoff rate by around 15%. In general, micro-basin tillage with optimal block interval represents an effective soil and water conservation practice for sloping farmland of the black soil region.


Subject(s)
Agriculture/methods , Conservation of Natural Resources/methods , Soil/chemistry , Water Supply , Water/analysis , China , Rain , Seasons , Zea mays/growth & development
17.
Can J Ophthalmol ; 39(4): 335-42, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15327097

ABSTRACT

In this article the author discusses advances in the treatment of ocular melanoma over the past 25 years. However, owing to metastatic disease, patient survival has not improved. Research into molecular and cellular biology and genetic factors is needed to better understand metastasis in order to improve survival.


Subject(s)
Melanoma/pathology , Uveal Neoplasms/pathology , Forecasting , Humans , Melanoma/mortality , Melanoma/therapy , Survival Rate , Uveal Neoplasms/mortality , Uveal Neoplasms/therapy
18.
Can J Ophthalmol ; 49(5): 464-7, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25284104

ABSTRACT

OBJECTIVE: This study aimed to assess the ocular and metastatic outcomes of patients with choroidal indeterminate melanocytic lesions treated by primary transpupillary thermotherapy (TTT). DESIGN: Retrospective case series. PARTICIPANTS: Eight patients presenting choroidal indeterminate melanocytic lesions treated by primary TTT. METHODS: A retrospective chart review was conducted for patients with a newly diagnosed choroidal indeterminate melanocytic lesion treated by at least 3 TTT sessions from 2002 to 2011. Best-corrected visual acuity and lesion dimensions were measured at baseline and during follow-up. Complications were recorded including lesion growth, metastasis, melanoma-related mortality, and treatment-related complications. RESULTS: Mean initial thickness was 2.0 ± 0.8 mm. Patients had an average of 3.0 ± 0.9 risk factors for lesion growing. Three patients (38%) had lesion growth. Two patients (25%) had severe visual loss (>1.0 logMAR) directly related to TTT treatment. There were no fatalities due to metastasis. CONCLUSIONS: Despite careful patient selection and systematic treatment with at least 3 TTT sessions, the use of primary TTT to treat patients with choroidal indeterminate melanocytic lesions with ≥ 1 risk factor for lesion growth yielded poor local lesion control and the possibility for severe ocular complications.


Subject(s)
Choroid Neoplasms/therapy , Hyperthermia, Induced/methods , Nevus, Pigmented/therapy , Adult , Aged , Choroid Neoplasms/mortality , Choroid Neoplasms/pathology , Female , Follow-Up Studies , Humans , Hyperthermia, Induced/adverse effects , Male , Middle Aged , Nevus, Pigmented/mortality , Nevus, Pigmented/pathology , Pupil , Retrospective Studies , Survival Rate , Treatment Outcome , Visual Acuity/physiology
19.
Invest Ophthalmol Vis Sci ; 55(3): 1277-83, 2014 Mar 04.
Article in English | MEDLINE | ID: mdl-24481264

ABSTRACT

PURPOSE: Overexpression of hypoxia inducible factor-1 α (HIF-1α) has been found in several cancers and is thought to correlate with aggressive disease. The purpose of our study was to investigate the influence of HIF-1α on clinical outcome in uveal melanoma (UM) along with proliferative (MIB-1) and vascular (CD31, VEGF-A) markers. METHODS: A retrospective analysis was carried out on UM tumors from 88 patients. HIF-1α, MIB-1, CD31, and VEGF-A expression, as well as necrosis, were assessed by immunohistochemistry and hematoxylin/eosin on paraffin-embedded UM tumor sections by using a tissue microarray. The bivariate analysis involving HIF-1α expression and clinicopathologic covariates was performed by using the χ(2) test. The association of clinicopathologic covariates and HIF-1α expression with patient survival was evaluated by using the Kaplan-Meier approach and Cox proportional-hazards regression analysis. RESULTS: Among our study population, 56 patients (63.6%) had high levels of HIF-1α expression. High expression of HIF-1α was associated with high expression of MIB-1 (P = 0.04), CD31 (P = 0.03), and VEGF-A (P < 0.0001), as well as necrosis (P = 0.04). However, high HIF-1α expression was not correlated with cell type, largest macroscopic tumor dimension or thickness, anterior margin, pigmentation, or mitotic figures. Patients with high HIF-1α expression did not show a reduced survival when compared to patients with low HIF-1α expression (P = 0.92). Finally, HIF-1α expression was not increased after irradiation. CONCLUSIONS: An increase in HIF-1α expression was significantly associated with proliferative (MIB-1) and vascular (CD31 and VEGF-A) markers, as well as necrosis, in UM. However, there was no correlation between high HIF-1α expression and patient survival.


Subject(s)
Cell Proliferation , Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis , Melanoma/metabolism , Platelet Endothelial Cell Adhesion Molecule-1/metabolism , Uveal Neoplasms/metabolism , Vascular Endothelial Growth Factor A/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/metabolism , Female , Humans , Immunohistochemistry , Male , Melanoma/pathology , Middle Aged , Prognosis , Retrospective Studies , Tissue Array Analysis , Uveal Neoplasms/pathology , Young Adult
20.
J Wildl Dis ; 49(1): 39-48, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23307370

ABSTRACT

Toxoplasma gondii, one of the more common zoonotic parasites in the world, can cause serious illness in humans and other animals worldwide. Felids are the only known host that can shed T. gondii oocysts, which are essential to the perpetuation of the parasite. In much of boreal Canada, the Canadian lynx (Lynx canadensis) is the only wild felid host that could contribute to environmental contamination with T. gondii oocysts. We estimated the prevalence of T. gondii antibodies in Canadian lynx from western Québec and compared our results with earlier findings in the same region 12 yr earlier. We investigated factors associated with seroconversion, including age, sex, geographic location, and possible co-occurrence with domestic cats (Felis catus), and we assessed the proportion of lynx shedding T. gondii oocysts. Blood and fecal samples were collected from 84 lynx harvested by trappers in the eastern part of the study area during winter 2009-2010. Sera were tested for antibodies to T. gondii by the modified agglutination test (cutoff titer 1:50) and fecal samples for parasite eggs by fecal flotation. Antibodies to T. gondii were detected in sera of 14% of 84 lynx. Numerous helminth ova and coccidian oocysts were found in feces, whereas T. gondii-like oocysts were not detected. Antibody prevalence increased with age class (odds ratio [OR]=4.33, 95% confidence interval [CI]=1.57-11.99, P<0.01). Antibody prevalence (14%) in our study was significantly lower than in 84 lynx (36%) trapped in the western part of the study area during winter 1997-1998 (OR=0.18, 95% CI=0.08-0.44, P<0.001). Our results suggest there may be significant spatiotemporal dynamics of T. gondii infection in lynx in Canada, and we review possible abiotic and biotic ecologic factors supporting these findings.


Subject(s)
Antibodies, Protozoan/blood , Lynx/parasitology , Toxoplasmosis, Animal/epidemiology , Age Factors , Animals , Cat Diseases/epidemiology , Cat Diseases/transmission , Cats , Disease Reservoirs/parasitology , Disease Reservoirs/veterinary , Feces/parasitology , Female , Male , Odds Ratio , Parasite Egg Count/veterinary , Quebec/epidemiology , Seroepidemiologic Studies , Sex Factors , Toxoplasmosis, Animal/transmission
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