Mainstream Deammonification: Preliminary Experience Employing Granular AOB-Enriched Biomass at Low DO Values     

M. Salmistraro  I. Fernández  J. Dosta  E. Plaza  J. Mata 《Water, air, and soil pollution》2017,228(5):178

The deammonification process represents one of the most convenient pathways for nitrogen removal from wastewater. A great deal of scientific articles dwells on the treatment of sidestream fluxes, whereas applications to mainstream waters represent a novel field. Among the general challenges of deammonification, one of the most important is the effective selection of ammonia oxidizers (AOB) over nitrite oxidizers (NOB), but also the typical slow start-up periods. In addition to such issues, mainstream deammonification has to face water temperatures and alkalinity reserves lower than those of sidestream fluxes and higher content of organic matter. An attempt was made to tackle such challenges by employing a lab-scale plant; low dissolved oxygen (DO) values (average 0.78 mg/L) and granular AOB-enriched biomass were used in order to address exclusion of nitrite oxidizers. The granules also allowed better biomass retention. The hydraulic retention time (HRT) was established initially at 24 h and later decreased to 12 h, as to possibly enhance the performance of the reactor. After 52 days of operation, Anammox biomass was also inoculated to the reactor. The results showed a maximum nitrogen removal efficiency of 54%. Moreover, little quantities of nitrates were observed throughout the experiment (<5 mg N/L twice, under the limit of quantification the rest of the sampling days), meaning that NOB out-selection techniques worked properly. Retention of biomass was also positively addressed and yielded a final SRT value of 15.6 days. Therefore, the proposed solution for mainstream deammonification was demonstrated to be promising and more research would be necessary to optimize it.  相似文献   

Monitoring neonicotinoid resistance in biotype B of Bemisia tabaci in Florida     

David J Schuster  Rajinder S Mann  Marco Toapanta  Roberto Cordero  Sandra Thompson  Sabrina Cyman  Aaron Shurtleff  Roy F Morris II 《Pest management science》2010,66(2):186-195

BACKGROUND: Biotype B of the sweetpotato whitefly, Bemisia tabaci (Genn.), is a worldwide pest that has developed resistance to many insecticides, including the neonicotinoid class. Florida field populations were monitored for susceptibility to the neonicotinoids imidacloprid and thiamethoxam using a cut leaf petiole bioassay method. RESULTS: Average RR₅₀ values for imidacloprid increased from 3.7 in 2000 to 12.0 in 2003; decreased to 5.0 and 2.5 in 2004 and 2005, respectively; and then increased to 26.3 and 23.9 in 2006 and 2007, respectively. Populations with RR₅₀ values of about 50 to 60 during generation one reverted to RR₅₀ values of ?4 in six generations, when reared without further exposure to imidacloprid. Average RR₅₀ values for thiamethoxam increased from 2.0 in 2003 to 24.7 in 2006 and decreased to 10.4 in 2007. Populations with RR₅₀ values of about 22, 32 and 53 during generation one declined to 8, 5 and 6, respectively, after being reared for five generations without exposure to thiamethoxam. The correlation coefficient from the 26 populations that were bioassayed both with imidacloprid and thiamethoxam showed a significant positive correlation (R² = 0.58) between these populations. CONCLUSION: The high level of RR₅₀ values to imidacloprid and thiamethoxam suggest an unstable decline in the susceptibility of B. tabaci to imidacloprid and thiamethoxam, with possible cross‐resistance or predisposition for dual resistance selection. Copyright © 2009 Society of Chemical Industry  相似文献   

Potential effect of increasing the water content in the digestibility of microdiets for fish larvae          下载免费PDF全文

M. Yúfera  J.A. Mata‐Sotres  C. Navarro‐Guillén  F.J. Moyano  G. Martínez‐Rodríguez 《Aquaculture Nutrition》2016,22(5):1116-1125

This study aimed to find a way for increasing the water content after rehydration of microdiet particles for fish larvae and to assess whether such increase contributes to a better disaggregation and digestion of particles within the gut of gilthead seabream larvae (4–15 days after hatching, dph). Four microdiets were prepared with increasing amounts of carboxymethylcellulose (CMC): 0, 20, 40 and 80 g kg^?1. The inclusion of CMC resulted in an effective increase of the hydration capacity of particles. Water content after immersion ranged from 800 g kg^?1 in the microdiet without CMC to 900 g kg^?1 with 80 g kg^?1 CMC. Larvae of different ages were fed during 10 h with these microdiets. The microparticles containing 80 g kg^?1 CMC were more degraded in the gut of the younger larvae. No clear differences were observed from 10 dph onwards. Differences in enzymatic activities were not evident except for α‐amylase in 6 dph larvae. Gene expression of the enzyme precursors did not show any relation to the water content of microdiets. Overall, the results indicate that increasing the water content up to 900 g kg^?1 may enhance the disintegration of food particles within the gut of younger larvae and to a lesser extent affect the response of digestive enzyme activities.  相似文献   

Ectopic ureter ‐ a leaky problem no matter how you look at it!     

H. C. Schott II 《Equine Veterinary Education》2011,23(12):603-605

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Automated irrigation of apple trees based on measurements of light interception by the canopy     

Jaume Casadesús  Mercè Mata  Jordi Marsal  Joan Girona 《Biosystems Engineering》2011,108(3):220-226

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Long-term successful outcome of a Streptococcus equi subspecies equi brain abscess     

H. C. Schott II  M. M. Esser  C. G. Pirie  A. P. Pease  J. S. Patterson  S. M. Reed 《Equine Veterinary Education》2020,32(10):e194-e198

We previously described successful treatment, including surgical drainage, of a Streptococcus equi subspecies equi brain abscess that caused severe neurological deficits in a 7-year-old Quarter Horse mare. This report details the long-term successful outcome of the case, findings of a magnetic resonance imaging (MRI) study performed 14 years after surgery and necropsy findings 18 years after initial treatment. Despite persistent cerebral and midbrain lesions detected by MRI and at necropsy, the mare returned to serviceable function within a year of initial treatment and had a successful performance career for over 10 years until carpal arthritis prompted retirement. This case demonstrates that brain abscess in horses can be successfully managed by combined medical and surgical treatment.  相似文献   

Factors involved in alleviating water stress by partial crop removal in pear trees     

Marsal J  Mata M  Arbones A  Del Campo J  Girona J  Lopez G 《Tree physiology》2008,28(9):1375-1382

We studied the relief of water stress associated with fruit thinning in pear (Pyrus communis L.) trees during drought to determine what mechanisms, other than stomatal adjustment, were involved. Combinations of control irrigation (equal to crop water use less effective rainfall) and deficit irrigation (equal to 20% of control irrigation), fruit load (unthinned and thinned to 40 fruits per tree) and root pruning (pruned and unpruned) treatments were applied to pear (cv. 'Conference') trees during Stage II of fruit development. Daily patterns of midday stem water potential (Psi(stem)) and leaf conductance to water vapor (g(l)) of deficit-irrigated trees differed after fruit thinning. In response to fruit thinning, gl progressively declined with water stress until 30 days after fruit thinning and then leveled off, whereas the effects of decreased fruit load on Psi(stem) peaked 30-40 days after fruit thinning and then tended to decline. Soil water depletion was significantly correlated with fruit load during drought. Our results indicate that stomatal adjustment and the resulting soil water conservation were the factors determining the Psi(stem) response to fruit thinning. However, these factors could not explain differences in daily patterns between g(l) and Psi(stem) after fruit thinning. In all cases, effects of root pruning treatments on Psi(stem) in deficit-irrigated trees were transitory (Psi(stem) recovered from root pruning in less than 30 days), but the recovery of Psi(stem) after root pruning was faster in trees with low fruit loads. This behavior is compatible with the concept that the water balance (reflected by Psi(stem) values) was better in trees with low fruit loads compared with unthinned trees, perhaps because more carbon was available for root growth. Thus, a root growth component is hypothesized as a mechanism to explain the bimodal Psi(stem) response to fruit thinning during drought.  相似文献   

High intakes of l⁺ and d⁻ lactic acid are efficiently metabolized by pigs and rats     

II. Everts  N. Salden  A. G. Lemmens  J. Wijers  A. C. Beynen 《Journal of animal physiology and animal nutrition》2000,83(4-5):224-230

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Pacific herring, Clupea pallasi, recruitment in the Bering Sea and north-east Pacific Ocean, II: relationships to environmental variables and implications for forecasting   总被引：1，自引：0，他引：1  

Erik H. Williams  & Terrance J. Quinn II 《Fisheries Oceanography》2000,9(4):300-315

Previous studies have shown that Pacific herring populations in the Bering Sea and north-east Pacific Ocean can be grouped based on similar recruitment time series. The scale of these groups suggests large-scale influence on recruitment fluctuations from the environment. Recruitment time series from 14 populations were analysed to determine links to various environmental variables and to develop recruitment forecasting models using a Ricker-type environmentally dependent spawner–recruit model. The environmental variables used for this investigation included monthly time series of the following: southern oscillation index, North Pacific pressure index, sea surface temperatures, air temperatures, coastal upwelling indices, Bering Sea wind, Bering Sea ice cover, and Bering Sea bottom temperatures. Exploratory correlation analysis was used for focusing the time period examined for each environmental variable. Candidate models for forecasting herring recruitment were selected by the ordinary and recent cross-validation prediction errors. Results indicated that forecasting models using air and sea surface temperature data lagged to the year of spawning generally produced the best forecasting models. Multiple environmental variables showed marked improvements in prediction over single-environmental-variable models.  相似文献   

Genetic divergence among gerbera accessions evaluated by RAPD     

Thiago Luiz Da Mata  Monique Inês SegerenAline Segeren Fonseca  Carlos Augusto Colombo 《Scientia Horticulturae》2009

Genetic diversity was evaluated by RAPD markers and morpho-agronomic characters for a total of 42 accessions of Barberton daisy (Gerbera jamesonii) consisting of 29 commercial and 13 wild accessions. A total of 74 polymorphic bands were obtained employing a set of 12 primer pairs. The average genetic similarity coefficient for the 42 accessions, evaluated by Jaccard index was 0.55 ranging from 0.28 to 1.00. The genetic structure found among Barberton daisy accessions was evaluated by hierarchic classification analyses and UPGMA modeling, revealing six clusters of genotypes where two of them include the wild accessions and the remaining four including commercial material, except for wild genotype number 9. Shannon (H′) index was calculated using the molecular markers to investigate the genetic variation among the Gerbera accessions and showed higher values for the commercial cluster in comparison to the values obtained for the individuals from the non-commercial cluster, namely 0.34 versus 0.27, respectively. Therefore, both calculated indices (Jaccard and Shannon) indicated the presence of higher genetic variation among commercial accessions in comparison to the cluster representing non-commercial accessions, suggesting that genetic breeding programs may focus on commercial accessions to recombine interesting genotypes with commercially important and marketing-desired characteristics.  相似文献