Modeling ammonia emissions from dairy production systems in the United States

Dairy production systems are hot spots of ammonia (NH3) emission. However, there remains large uncertainty in quantifying and mitigating NH3 emissions from dairy farms due to the lack of both long-term field measurements and reliable methods for extrapolating these measurements. In this study, a process-based biogeochemical model, Manure-DNDC, was tested against measurements of NH3 fluxes from five barns and one lagoon in four dairy farms over a range of environmental conditions and management practices in the United States. Results from the validation tests indicate that the magnitudes and seasonal patterns of NH3 fluxes simulated by Manure-DNDC were in agreement with the observations across the sites. The model was then applied to assess impacts of alternative management practices on NH3 emissions at the farm scale. The alternatives included reduction of crude protein content in feed, replacement of scraping with flushing for removal of manure from barn, lagoon coverage, increase in frequency for removal of slurry from lagoon, and replacement of surface spreading with incorporation for manure land application. The simulations demonstrate that: (a) all the tested alternative management practices decreased the NH3 emissions although the efficiency of mitigation varied; (b) a change of management in an upstream facility affected the NH3 emissions from all downstream facilities; and (c) an optimized strategy by combining the alternative practices on feed, manure removal, manure storage, and land application could reduce the farm-scale NH3 emission by up to 50%. The results from this study may provide useful information for mitigating NH3 emissions from dairy production systems and emphasize the necessity of whole-farm perspectives on the assessment of potential technical options for NH3 mitigation. This study also demonstrates the potential of utilizing process-based models, such as Manure-DNDC, to quantify and mitigate NH3 emissions from dairy farms

THE VELOCITY STRUCTURE OF APPROACH AND PERFORMANCE IN THE LONG JUMP

The purpose of this study was to examine the velocity structure of the approach in the long jump event. The effect of approach technique in overall performance will also be assessed, using biomechanical analysis. 527 full run-up horizontal velocity curves of long Jump measured in 527 trials using an SCL-Ⅱ Model Sports Radar Velocity Finder Instrument were analyzed and summarized. From the data, it was concluded that the full run-up of the long jump, measured in horizontal velocity curves could be classified into five types (platform type, gentle descending type, rapid descending type, multi-peak type and tailrising type). By keeping the velocity change of approach at a stable rate and maintaining high speed in the sprint, the jumper can achieve a good performance. The acceleration style of approach can be divided into two types (rapid rising type and gentle rising type). The change of acceleration velocity value reveals the long jumper's velocity ability and the stability of run-up. The difference in accelerating ability among jumpers at different levels appeared during the first second after the start. Elite long jumpers who run fast after starting often obtain good results

Investigation on the changes of corneal curvature after non-phacoemulsification in small-incision cataract surgery with intraocular lens implantation

AIM: To investigate the changes of corneal curvature after non-phacoemulsification in small-incision cataract surgery with intraocular lens implantation and discuss the essence of iatrogenic astigmatism. <p>METHODS: In this study, the horizontal corneal curvature(HCC)and vertical corneal curvature(VCC)of 99 patients(116 eyes)were documented before and after cataract surgery,with the postoperative follow-up of 3d; 1, 2wk; 1, 3, 6mo; 1, 2, 3a. The difference value of the HCC and the VCC between preoperation and postoperation were calculated and statistically analyzed. <p>RESULTS: The VCC was deceased by 2.01D, while the HCC was increased by 1.62D on the 3d after surgery; the difference value of the HCC and VCC were both decreased acutely in the 3mo postoperationly(the difference value of the VCC was -0.52D and HCC was 0.46D); the difference value of the HCC and VCC both were decreased mildly after 3mo of postoperation, There was no significant difference between the difference value of HCC(0.29D)and VCC(-0.29D)at 6mo(<i>P</i>=0.801); VCC was still smaller than that of preoperation(-0.26D), and HCC was larger than that of preoperation(0.25D)at the 3a. Paired <i>t</i> test was performed in these curvature differences, which both decreased apparently from 3d to 6mo after surgery(<i>P</i><0.001), while they stayed still from 6mo to 3a postoperatively(VCC: <i>P</i>=0.284; HCC:<i>P</i>=1.000). <p>CONCLUSION: It remains astigmatism for a short time after small-incision cataract surgery and the treatment requires improvement so as to minimize the astigmatism as much as possible

Human Papillomavirus Infection in Relation to Vaginal Microflora and Immune Factors

Objective: Clarify the vaginal microflora and immune factors in women with human papilloma virus (HPV) infection, and explore its association with HPV infection. Methods: This study collected vaginal secretions and blood from 160 women initially diagnosed as HPV positive in our hospital from June 2020 to December 2020 and 80 healthy women with HPV negative physical examination in the same period. The vaginal microflora of the patients were detected by 16S rDNA sequencing and the expression of immune factors was measured by a high-performance liquid phase chip. Results: The different types of HPV were HPV mix (64,40%), HPV52 (39,24.375%), HPV16 (30,18.750%), HPV58 (18,11.250%), HPV18 (6,3.750%), HPV53 (1,0.625%), HPV55 (1,0.625%), and HPV68 (1,0.625%).α diversity analysis showed that there was no significant difference in vaginal microflora between different HPV types (P=0.733). The genus level abundance of vaginal microflora in each group was mainly Lactobacillus, followed by Gardnerella and Prevotella. LEfSe Analysis showed that the mix group was Gardnerella and the type HPV16 group was Streptococcus. The immune comparison showed that MIP-1β was significantly upregulated in the HPV-positive group, but EGF in the HPV-negative group. Conclusion: This study revealed that HPV infection can change the proportion of vaginal microbial bacteria and the expression of immune factors, which provides a basis for local vaginal treatment and prevention of HPV infection after HPV infection