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121.
BackgroundCanine herpesvirus type 1 (CaHV-1) infects dogs and is associated with neonatal deaths and reproductive, ocular, neurological, and respiratory problems. In Brazil, reports of CaHV-1 have been restricted to the southeast and south regions, particularly in municipalities in the state of Rio Grande do Sul.ObjectivesTo assess the presence and variability of CaHV-1 in canine populations in the state of Pará, North Brazil.MethodsBiological samples from 159 dogs from 4 municipalities in the State of Pará were evaluated using polymerase chain reaction and phylogenetic analyses, with the target being the viral enzyme, thymidine kinase.ResultsCaHV-1 was detected in 13 dogs (8.2%), with 2 animals being from the municipality of Santa Bárbara do Pará, 8 from Algodoal Island, 2 from Salinópolis, and one from Capanema. The study sequences revealed 100% identity among themselves and 64% to 100% identity with the other nucleotide sequences from Australia, Brazil, United Kingdom, and United States, including 100% identity with the 2002 isolate from Australia. The 1996 isolate from France was grouped in a branch that was different from the sequence of this study.ConclusionsThis study presents the first molecular detection of CaHV-1 in dogs from the Amazon region in northern Brazil. The nucleotide identity between the strains and cytosine insertion in the sequences isolated in this study suggests at least 2 strains of CaHV-1 circulating in Brazil (Pará and BTU-1).  相似文献   
122.

Purpose  

An in situ phytoremediation trial was developed in order to investigate the function of alfalfa during a 2-year bioremediation of an agricultural soil contaminated with polychlorinated biphenyls (PCBs). The study was conducted with the aim to better understand the application potential of PCB phytoremediation at field scale.  相似文献   
123.
The threat imposed by increased sediment loading rates ranks among the most important stressors affecting coral reef ecosystems worldwide. This study represents an effort to quantify the effects of unpaved roads on erosion rates in a dry sub-tropical area of Puerto Rico and is intended to aid in developing scientifically-based erosion mitigation strategies. Hence, the specific objectives of this study were to: (1) measure sediment production rates from unpaved roads; (2) evaluate the effect of precipitation, rainfall erosivity, slope, plot length, and vegetation cover on sediment production rates; and (3) compare measured sediment production rates to published surface erosion data from roaded and natural sites in the Eastern Caribbean. Sediment production from nine abandoned road segments with varying slopes and plot lengths were measured with sediment traps in southwestern Puerto Rico from August 2003 to September 2005.  相似文献   
124.
125.
Total gaseous mercury (TGM) fluxes from the forest floor and a boreal wetland were measured by a flux chamber technique coupled with an automatic mercury vapour analyser. The fluxes were measured at three sampling sites in southern Finland, 61°14′ N, 25°04′ E in summer 2007, with additionally in situ TGM concentrations in the air at one of the sites and mercury bulk deposition at another. Most of the flux data were collected during the daytime. At one of the sites, diurnal flux behaviour was studied, and a clear cycle with an afternoon maximum and a night minimum was observed. The highest emissions (up to 3.5 ng m−2 h−1) were observed at the forest floor site having a moss and grass cover. At the wetland and litter-rich forest floor sites, the emissions were below 1 ng m−2 h−1 and sometimes negative (down to −1.0 ng m−2 h−1), indicating mercury uptake. The measured average fluxes in August were 0.9 ± 1.1 and 0.2 ± 0.3 ng m−2 h−1 for the forest floor sites and wetland sites, respectively. The flux data were compared with the mercury bulk deposition, which proved to be of the same magnitude, but opposite in sign. At the mossy forest floor site, the extrapolated TGM emissions were 130% of the Hg deposition in August 2007. Comparison with other studies showed that the fluxes in background areas are relatively uniform, regardless of measurement site location and method used. Airborne TGM remained at the background level during the study, with an average value of 1.3 ± 0.2 ng m−3; it frequently showed a diurnal cycle pattern.  相似文献   
126.

Purpose  

Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil were reported in this study.  相似文献   
127.
Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study was to investigate the treatment of diazo dye Reactive Black 5 (RB5)-containing wastewater using granular activated carbon (GAC)–biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC–biofilm SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k 2) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased from 100 to 200 mg/l in the GAC–biofilm SBR system.  相似文献   
128.

Purpose

Soil microorganisms are important in the cycling of plant nutrients. Soil microbial biomass, community structure, and activity are mainly affected by carbon substrate and nutrient availability. The objective was to test if both the overall soil microbial community structure and the community-utilizing plant-derived carbon entering the soil as rhizodeposition were affected by soil carbon (C) and nitrogen (N) availability.

Materials and methods

A 13C-CO2 steady-state labeling experiment was conducted in a ryegrass system. Four soil treatments were established: control, amendment with carboxymethyl cellulose (CMC), amendment with ammonium nitrate (NF), combined CMC and NF. Soil phospholipid fatty acid (PLFA) and 13C labeling PLFA were extracted and detected by isotope ratio mass spectrometer.

Results and discussion

The combined CMC and NF treatment with appropriate C/N ratio (20) significantly enhanced soil microbial biomass C and N, but resulted in lower soil inorganic N concentrations. There was no significant difference in soil PLFA profile pattern between different treatments. In contrast, most of the 13C was distributed into PLFAs 18:2ω6,9c, 18:1ω7c, and 18:1ω9c, indicative of fungi and gram-negative bacteria. The inorganic-only treatment was distinct in 13C PLFA pattern from the other treatments in the first period of labeling. Factor loadings of individual PLFAs confirmed that gram-positive bacteria had relatively greater plant-derived C contents in the inorganic-only treatment, but fungi were more enriched in the other treatments.

Conclusions

Amendments with CMC can improve N transformation processes, and the ryegrass rhizodeposition carbon flux into the soil microbial community is strongly modified by soil N availability.
  相似文献   
129.

Purpose

Under a global warming scenario, understanding the response of soil organic carbon fractions and aggregate stability to temperature increases is important not only for better understanding and maintaining relevant ecosystem services like soil fertility and crop productivity, but also for understanding key environmental processes intimately related with the maintenance of other regulatory ecosystem services like global climate change mitigation through carbon sequestration. An increase in temperature would accelerate the mineralization of soil organic carbon. However, the properties of organic carbon remained in soil after mineralization is not well known.

Materials and methods

Mollisol was collected at 0–20-cm depth from maize (Zea mays L.) field in Northeast China. A 180-day incubation experiment was conducted at three different temperatures (10, 30, and 50 °C) under constant soil moisture (60 % water holding capacity). Soil samples were assayed for total organic carbon (TOC), water-soluble organic carbon (WSOC), easily oxidizable organic carbon (EOC), humic fractions carbon, aggregate-associated carbon, and water stability of aggregates. Elemental analysis and solid-state 13C nuclear magnetic resonance spectroscopy were used to characterize humic acid and humin fractions.

Results and discussion

The contents of soil TOC, EOC, humic fractions carbon, and aggregate-associated carbon decreased with the increase in temperature. The proportion of 2–0.25-mm macroaggregate and the mean weight diameter (MWD) of aggregates also decreased. The C, H, N, S, alkyl C, and O-alkyl C contents of humic acid and humin decreased, whereas the O, aromatic C, and carbonyl C contents increased. The H/C, aliphatic C/aromatic C, and O-alkyl C/aromatic C ratios in humic acid and humin fractions decreased.

Conclusions

The increase in temperature has a negative impact on soil organic carbon content, soil aggregation, and aggregate stability. Moreover, humic acid and humin molecules become less aliphatic and more decomposed with the increase in temperature.
  相似文献   
130.
Emmer wheat (Triticum dicoccon Schrank, 2n = 4x = 28) consists in a hulled wheat; its cultivation has been drastically reduced during the last century as a consequence of its low yield. Recently, its agronomic and nutritive values, as well as the increase of popularity of organic agriculture, have led to a renewed interest making its cultivation economically viable in the marginal lands with an increase of the cultivated areas. In Italy, it mainly survives in few marginal lands of central and southern Italy, where local varieties, adapted to the natural environment from where they originate, are used; moreover, some selected lines have also been developed. In the present work, agro-morphological and qualitative traits, together with molecular analyses of 20 emmer accessions consisting of Italian landraces, breeding lines, and cultivars, were performed. The field experiments were conducted for two consecutive years (2001/2002–2002/2003) in two locations: Viterbo in central Italy, and Foggia in south Italy. The analyzed emmer wheat accessions showed a good amount of genetic variability for both evaluated agro-morphological and molecular traits. This study illustrates an increase in earliness, GY, TW, TKW, and YI going from landraces, breeding lines to cultivars, while the variability does not change proportionally.  相似文献   
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