功能膜覆盖好氧堆肥过程氨气减排性能研究

畜禽粪便高温好氧堆肥过程中氨气的排放不仅污染环境,而且会降低有机肥氮素含量。因此,控制好氧堆肥过程中氨挥发是降低氮损失及减少堆肥周边环境恶臭的关键。为研究膜覆盖对畜禽粪便好氧堆肥过程氨气挥发的影响,以猪粪和小麦秸秆为试验原料,采用具有选择渗透性的Gore膜作为覆盖材料,在实验室好氧堆肥反应器系统中进行了为期27 d的好氧堆肥试验。试验设置覆膜组和对照组,采用开启1 h、关闭1 h间歇通风方式,通风速率为3 L/min,重点监测堆肥过程堆体温度、氧浓度和NH3排放速率等。研究表明:覆膜组比对照组高温期持续时间略长,更有利于杀死堆体有害病原菌;相比于对照组,覆膜组NH3排放量减少18.87%;相比于温度峰值出现的时间,两组试验NH3峰值出现时间均延后,且覆膜组延后时间更长。     

An example of meso‐scale hydrographic features in the central Baltic Sea and their influence on the distribution and vertical migration of sprat,Sprattus sprattus balticus (Schn.)

A wind‐driven meso‐scale pattern of temperature, salinity and oxygen was found along a transect in the northern Bornholm Basin (southern Baltic Sea). Strong winds caused currents along this transect, which shifted cold intermediate water (minimum: 3.6°C) towards the south. The transect was surveyed with a towed CTD‐system and hydroacoustics in parallel to investigate the distribution of sprat, Sprattus sprattus balticus (Schn.) in relation to the observed meso‐scale pattern. In those parts of the transect where the cold intermediate water was observed, sprat were restricted to water layers below the halocline. In other parts of the transect, sprat moved into higher water layers and occupied a wider depth range. The important factor was temperature, which set an upper limit to the vertical sprat distribution. The development of hydrography, as measured in the field, was evaluated with a hydrodynamic model.     

PROTON SPOT SCANNING RADIOTHERAPY OF SPONTANEOUS CANINE TUMORS

Thirty dogs with spontaneous tumors were irradiated with proton therapy using a novel spot scanning technique to evaluate the safety and efficacy of the system, and to study the acute and late radiation reactions. Nasal tumors, soft tissue sarcomas, and miscellaneous tumors of the head were treated with a median total dose of 52.5 Gy given in 3.5 Gy fractions. Acute effects, late effects, tumor response, and outcome were analyzed. No unexpected radiation reactions were seen, however two dogs did develop in-field osteosarcoma, and one dog developed in-field bone necrosis. Complete response to therapy was seen in 40% (12/30), partial response in 47% (14/30), and no response in 13% (4/30). Median survival for all dogs was 385 days (range of 14–4583 days). Dogs with nasal cavity tumors had a median survival of 385 days (range of 131–1851 days) and dogs with soft tissue sarcomas had a median survival time of 612 days (range of 65–4588 days). Treatment outcome was similar to historical controls. This new proton spot scanning technique proved to be safe and reliable.     

POTENTIAL FOR INTENSITY-MODULATED RADIATION THERAPY TO PERMIT DOSE ESCALATION FOR CANINE NASAL CANCER

We evaluated the impact of inverse planned intensity-modulated radiation therapy (IMRT) on the dose-volume histograms (DVHs) and on the normal tissue complication probabilities (NTCPs) of brain and eyes in dogs with nasal tumors. Nine dogs with large, caudally located nasal tumors were planned using conventional techniques and inverse planned IMRT for a total prescribed dose of 52.5 Gy in 3.5 Gy fractions. The equivalent uniform dose for brain and eyes was calculated to estimate the normal tissue complication probability (NTCP) of these organs. The NTCP values as well as the DVHs were used to compare the treatment plans. The dose distribution in IMRT plans was more conformal than in conventional plans. The average dose delivered to one-third of the brain was 10 Gy lower with the IMRT plan compared with conventional planning. The mean partial brain volume receiving 43.6 Gy or more was reduced by 25.6% with IMRT. As a consequence, the NTCPs were also significantly lower in the IMRT plans. The mean NTCP of brain was two times lower and at least one eye could be saved in all patients planed with IMRT. Another possibility with IMRT is dose escalation in the target to improve tumor control while keeping the NTCPs at the same level as for conventional planning. Veterinary