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排序方式: 共有162条查询结果,搜索用时 15 毫秒
41.
42.
Boutet S Lomb L Williams GJ Barends TR Aquila A Doak RB Weierstall U DePonte DP Steinbrener J Shoeman RL Messerschmidt M Barty A White TA Kassemeyer S Kirian RA Seibert MM Montanez PA Kenney C Herbst R Hart P Pines J Haller G Gruner SM Philipp HT Tate MW Hromalik M Koerner LJ van Bakel N Morse J Ghonsalves W Arnlund D Bogan MJ Caleman C Fromme R Hampton CY Hunter MS Johansson LC Katona G Kupitz C Liang M Martin AV Nass K Redecke L Stellato F Timneanu N Wang D Zatsepin NA Schafer D Defever J 《Science (New York, N.Y.)》2012,337(6092):362-364
Structure determination of proteins and other macromolecules has historically required the growth of high-quality crystals sufficiently large to diffract x-rays efficiently while withstanding radiation damage. We applied serial femtosecond crystallography (SFX) using an x-ray free-electron laser (XFEL) to obtain high-resolution structural information from microcrystals (less than 1 micrometer by 1 micrometer by 3 micrometers) of the well-characterized model protein lysozyme. The agreement with synchrotron data demonstrates the immediate relevance of SFX for analyzing the structure of the large group of difficult-to-crystallize molecules. 相似文献
43.
Adult bean thrips, Caliothrips fasciatus (Pergande), over-wintering inside the navel of navel oranges in California are an export problem when detected in fruit sent to Australia. At present, a systems approach is used to reduce fruit infestation levels and one component of this approach is to search for thrips inside the navel by cutting 50 fruit per block prior to harvest and 75 fruit per grower lot before packing in the packinghouse with any detection of live bean thrips leading to that grower lot not being eligible for shipment to Australia. Given that bean thrips infestation levels are often 0.5% of the fruit or less, this amount of fruit cutting can lead to shipment of infested lots of citrus to Australia. As an alternative to cutting more fruit, two non-destructive methods of sampling for bean thrips inside the navel of navel oranges were investigated which might be used on larger numbers of fruit and result in fewer infested lots being shipped to Australia. A light trap at the apex of a pyramid-shaped black cloth tent caught 41.1% of adult bean thrips released at the bottom of the tent. When this experiment was repeated with the tent placed over a citrus bin two-thirds full of fruit, however, only 9.3% of thrips released at the bottom of the bin were captured. A second method of sampling, washing bean thrips out of the navel onto a screen, resulted in close to 90% recovery of thrips with each of the five spray rinses evaluated, including distilled water. Regression analysis indicated there was no statistical difference between results with the five rinses. Thus, it might be worthwhile trying to scale-up our laboratory method of rinsing with distilled water to a method that might be used in a commercial packinghouse for detection of bean thrips in large numbers of fruit. Even if one assumes that cutting fruit is 100% efficient in finding bean thrips inside the navel of navel oranges, sampling a much larger number of fruit using a method with 90% efficiency is shown to result in higher odds of finding any bean thrips that are present. 相似文献
44.
Occurrence of PPCPs at a Wastewater Treatment Plant and in Soil and Groundwater at a Land Application Site 总被引:1,自引:0,他引:1
Adcharee Karnjanapiboonwong Jamie G. Suski Ankit A. Shah Qingsong Cai Audra N. Morse Todd A. Anderson 《Water, air, and soil pollution》2011,216(1-4):257-273
Pharmaceuticals and personal care products (PPCPs) can reach soil and aquatic environments through land application of wastewater effluent and agricultural runoff. The objective of this research was to assess the fate of PPCPs at field scale. PPCPs were measured systematically in a wastewater treatment plant (WWTP), and in soil and groundwater receiving treated effluent from the WWTP. A land application site in West Texas was used as the study site; it has received treated wastewater effluent from the WWTP for more than 70 years in order to remove additional nutrients and irrigate non-edible crops. Target compounds (estrone, 17??-estradiol, estriol, 17??-ethynylestradiol, triclosan, caffeine, ibuprofen, and ciprofloxacin) in wastewater, sewage sludge, soil, and groundwater were determined using HPLC/UV with qualitative confirmatory analyses using GC/MS. Samples were collected quarterly over 12 months for wastewater and sludge samples and over 9 months for soil and groundwater samples. Results indicated that concentrations of PPCPs in wastewater influent, effluent, sludge solid phase, and sludge liquid phase were in the range of non-detected (ND)-183 ??g/L, ND-83 ??g/L, ND-19 ??g/g, and ND-50 ??g/L, respectively. Concentrations in soil and groundwater samples were in the range of ND-319 ng/g and ND-1,745 ??g/L, respectively. GC/MS confirmation data were consistent with the results of HPLC/UV analyses. Overall, data indicate that PPCPs in the wastewater effluent from the WWTP transport both vertically and horizontally in the soil, and eventually reach groundwater following land application of the effluent. 相似文献
45.
T. J. Kennedy E. A. Hernandez A. N. Morse T. A. Anderson 《Water, air, and soil pollution》2012,223(7):4527-4537
Safe drinking water is a luxury to approximately 800 million people worldwide. The number of people without access to clean water has been reduced, thanks to technologies like the biosand filter (BSF), an intermittently operated household scale slow sand filter. The BSF outlet (control diameter 0.5??) was modified in this study by reducing the outlet diameter (0.37?? and 0.25??) to determine the effects of hydraulic retention time on removal rates. Filters were dosed with 20?L of spiked lake water daily and observed for pH, dissolved oxygen (DO), fecal coliforms (FC), turbidity, nitrate, nitrite, sulfate, and ammonia until initial flow rates dropped below 0.2?L/min. Consistent with previous studies, the average turbidity was reduced to below 1?NTU; the average DO was reduced by 45?%. No significant difference was observed between the modified BSFs and the control BSF. Removal efficiency of FC was not significantly different between the modified BSFs (93.3?% and 91.9?%) and the control BSF (89.6?%). Mean FC reduction during the startup period (17?days) was significantly greater in the modified 0.25?? BSF when compared with the control during the same time period. After the first 17?days of the experiment, the average reduction efficiency of all filters was >97?%. While source water was below guideline values for nitrate, nitrite, ammonia, and sulfate during the course of the experiment, total nitrogen reduction was observed. The reduction indicates that the plastic BSF is capable of accomplishing limited denitrification during the filtering process. 相似文献
46.
Climate Change During the Last Deglaciation in Antarctica 总被引:1,自引:0,他引:1
PA Mayewski MS Twickler SI Whitlow LD Meeker Q Yang J Thomas K Kreutz PM Grootes DL Morse EJ Steig ED Waddington ES Saltzman P Whung KC Taylor 《Science (New York, N.Y.)》1996,272(5268):1636-1638
Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated. 相似文献
47.
Byrne FJ Urena AA Robinson LJ Krieger RI Doccola J Morse JG 《Pest management science》2012,68(5):811-817
BACKGROUND: Trunk injections of systemic insecticides were evaluated for the management of avocado thrips. Insecticide residues were quantified in leaves to determine when after treatment, and for how long, toxic concentrations of the insecticides were present. Residues in fruit were quantified to determine whether trunk injection of insecticides might present a greater risk than traditional application methods for contaminating fruit. RESULTS: Residues of imidacloprid and dinotefuran were at least tenfold higher in leaves when trees were treated via trunk injection compared with soil application. Dinotefuran uptake was more rapid than imidacloprid, and no residues were detected within fruit. Acephate was also mobilized very rapidly and gave good control of thrips in bioassays; however, residues of acephate and its insecticidal metabolite methamidophos were detected in the fruit for up to 4 weeks after injection. Avermectin uptake was very slow, and it was ineffective against avocado thrips. CONCLUSIONS: Trunk injections of acephate and dinotefuran permitted rapid uptake into avocados, and they are strong candidates as control methods for avocado thrips. However, residues of organophosphates in fruit could necessitate increased preharvest intervals. Residues of neonicotinoids were below detection limits in fruit, suggesting that neonicotinoids may be the more suitable control option of the two chemical classes. Copyright © 2012 Society of Chemical Industry 相似文献
48.
Background
The Irish Horse Industry expanded during the Celtic Tiger boom years, then contracted in the current economic recession. High value horses were traditionally controlled through sale at public auction, private sales and sales to dealers; these are now also being reduced by decreases in production (> 40%), and increases in retirement, re-homing, euthanasia and disposal through Category 2 plants and abattoirs. The absence or banning of horse abattoirs has been shown to have very significant welfare social and economic consequences in the USA. This study described the currently available data on the demographics of unwanted horses in Ireland from 2005 to 2010.Results
The majority of horses euthanised by practicing veterinarians are destroyed on medical grounds but the number euthanised at the request of welfare groups and the state, as well as welfare related calls and the number of horses involved in these calls and subsequent visits is increasing reflecting the increasing involvement of the veterinary profession in equine welfare. Welfare groups have limited resources and do not have a tradition of recording data, but they too have reported increasing calls, visits and numbers of horses per visit. Welfare groups provide significant service to equine welfare and the community. Local Authorities report similar trends. Over 300 horses were found dead or required immediate or subsequent euthanasia following welfare group and local authority visits in 2010, which is of national concern. The majority of local authority interfaces with unwanted horses are with urban (60%) rather than rural (40%) horses. Mortality figures are poor indicators of non-fatal neglect. More horses were admitted into the care of local authorities than welfare groups, reflecting significant state and taxpayer investment in the control of low value horses. Category 2 plants and abattoirs represent a significant state investment in licensing and control in the national interest. Abattoirs provide an increasingly important and essential service for the disposal of unwanted horses. Despite the increase in unwanted horses, Ireland is a minority contributor to the EU slaughter total.Conclusions
There is a need for annual demographic data compilation and review of the numbers of unwanted horses and ponies within the horse industry to assist policy makers and legislators. 相似文献49.
João CA. Alves Ana MMP. dos Santos Ângelo DP. Fernandes 《Veterinary anaesthesia and analgesia》2018,45(1):123-128
Objective
To evaluate the feasibility and effectiveness of mesotherapy in dogs compared with a positive control group.Study design
Experimental, randomized, blinded study.Animals
Fifteen working police dogs with chronic back pain.Methods
Animals were divided randomly into control (CG; n = 5) and treatment groups (TG; n = 10). A combination of 140 mg lidocaine, 15 mg dexamethasone and 20 mg thiocolchicoside was administered to group TG along with a 70-day course of a placebo, administered as if it was carprofen. Carprofen was administered to Group CG for 70 days, at a dose adjusted to their weight. On day 0, an intradermal injection of Ringer’s lactate was also administered. Both groups were rested for 3 days and resumed normal activity over a 5-day period. Response to treatment, measured by the Canine Brief Pain Inventory (CBPI) and the Hudson Visual Analogue Scale (HVAS), was evaluated before treatment (T0), after 15 days (T1) and 1 (T2), 2 (T3), 3 (T4), 4 (T5) and 5 (T6) months. Results were compared using a Mann–Whitney test or a paired samples t test.Results
When comparing CBPI results, no differences were found between groups TG and CG at T0 through T3 and in T6 and T7. Differences were observed in CBPI sections after the discontinuation of carprofen: at T4 [p = 0.02 for Pain Interference Score (PIS) and p = 0.03 for Pain Severity Score (PSS)] and T5 (p = 0.16 for PIS and p = 0.03 for PSS), with group TG having overall better results. Individual treatment results were considered successful in one dog of group CG (20%), whereas in group TG, success was higher (ranging from 78% at T1 to 22% at T7). No significant differences were registered with the HVAS.Conclusions and clinical relevance
Mesotherapy may be a promising treatment option for canine musculoskeletal-related pain. Further studies are required. 相似文献50.
Kelly P O'Sullivan K Berry D More S Meaney W O'Callaghan E O'Brien B 《Irish veterinary journal》2009,62(1):36-42
Research has shown that total bacterial count (TBC), which is the bacterial growth per ml of milk over a fixed period of time, can be decreased by good hygiene and farm management practices. The objective of the current study was to quantify the associations between herd management factors and bulk tank TBC in Irish spring calving, grass-based dairy herds. The relationship between bulk tank TBC and farm management and infrastructure was examined using data from 400 randomly selected Irish dairy farms where the basal diet was grazed grass. Herd management factors associated with bulk tank TBC were identified using linear models with herd annual total bacterial score (i.e., arithmetic mean of the natural logarithm of bulk tank TBC) included as the dependent variable. All herd management factors were individually analysed in a separate regression model, that included an adjustment for geographical location of the farm. A multiple stepwise regression model was subsequently developed. Median bulk tank TBC for the sample herds was 18,483 cells/ml ranging from 10,441 to 130,458 cells/ml. Results from the multivariate analysis indicated that the following management practices were associated with low TBC; use of heated water in the milking parlour; participation in a milk recording scheme; and tail clipping of cows at a frequency greater than once per year. Increased level of hygiene of the parlour and cubicles were also associated with lower TBC. Herd management factors associated with bulk tank TBC in Irish grazing herds were generally in agreement with most previous studies from confinement systems of milk production. 相似文献