播种机参数和打穴铲结构对投种影响的计算机仿真

根据铲式成穴器与倾斜圆盘勺式排种器组合设计成的打穴播种机的结构特点,建立了种子下落过程中运动轨迹的参数方程。以此为基础分析了播种机双向倾角、排种器投种角和打穴铲结构参数对种子在打穴铲内自由下落过程的影响,进而确定了打穴铲几何尺寸的设计原则。     

Determination of ecophysiological maintenance carbon requirements of soil microorganisms in a dormant state

Summary An experimental approach was attempted for determining the maintenance carbon requirements of the dormant microbial biomass of two agricultural soils (I, II) and one, forest soil (III). The amount of carbon needed for preventing microbial-C loss during incubation expressed as coefficient m (mg glucose-C·mg^-1 biomass-C·h^-1) was 0.00031, 0.00017 and 0.00017 h^-1 at 28°C and 0.000043, 0.000034 and 0.000016 h^-1 at 15°C for soils I, II and III, respectively. Depending on the temperature, the determined m values of the dormant population were two to three orders of magnitude below known values from pure cultures or m values of metabolically activated biomasses under in situ conditions. Corresponding microbial-C loss quotients were comparable to the observed maintenance coefficients but were always above m.The metabolic quotient q for CO₂ (mg CO₂-C·mg^-1 biomass-C·h^-1) of the dormant populations in the three soils tested was at q = 0.0018 h^-1 (22°C) one order of magnitude below metabolically activated cells but did not correspond to the low maintenance values determined, which implies that in addition to possible utilization of native soil organic matter dormant biomasses must largely have an endogenously derived respiratory activity.     

Die Mikroflora des Ackerbodens in Abhängigkeit von verschiedenen Fruchtfolgen

Zusammenfassung Durch den wiederholten Anbau artgleicher Kulturpflanzen werden im Boden Rückstände angereichert, die die Ausbildung spezifischer Dominanzen innerhalb einer Mikropopulation auslösen können.Die möglichen Populationsverschiebungen werden mit denen verglichen, die nach einer Bodenbearbeitung oder Anwendung von Agrochemikalien auftreten können.Die Beziehungen zwischen der mikrobiellen Aktivität des Bodens und der Entwicklung von Kulturpflanzen werden im Hinblick auf Höhe, Sicherheit und Qualität des Ertrages diskutiert.

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Repeated cropping with the same plant species results in an increase of residues in the soil which may cause the build-up of specific dominances within the micropopulation.The potential shifts in the population are compared with those occurring as a consequence of mechanical treatment as well as after the application of agrochemicals.The relations between the microbial activity of the soil and the development of crop plants are discussed with emphasis on quantity, stability and quality of yields.

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Résumé Plusieurs reprises d'une monoculture provoquent, dans le sol, l'enrichissement de résidus qui peuvent produire la prédominance de certaines espèces microbiennes.Les changements possibles de la population sont comparés avec ceux-là qui peuvent sortir de la culture du sol ou de l'application de certains produits chimiques.Les relations entre l'activité microbienne du sol et le développement des plantes cultivées sont discutées en vue de quantité, qualité et sûreté du rendement.

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Vortrag, gehalten auf der gemeinsamen Tagung der Internationalen Vereinigung zur Erforschung der Qualität von Nahrungspflanzen (CIQ) und der Deutschen Gesellschaft für Qualitätsforschung (Pflanzliche Nahrungsmittel) (DGQ) in Mainz (25.–27. März 1969) am 26.3.1969.     

马兰生物学特性及其生长环境初探

对马兰［Ｋａｌｉｍｅｒｉｓｉｎｄｉｃａ（Ｌ．）Ｓｃｈ－Ｂｉｐ］主要生物学特性进行了观察,并比较了５种不同生长环境的生长状况。结果表明：在土壤疏松、有机质丰富、肥力较强的栽培地上生长状况最好,产量最高;而在土壤紧实荫蔽条件下,生长最差,产量最低。这为马兰的人工驯化栽培提供了科学的依据。     

加快农产品加工业大发展面临的改革与选择

通过调查得到启示,就如何加快农产品加工业发展提出和论证了以下问题：加快农产品加工业发展需要全面的和深层次的转变观念;发展农产品加工业,要选准产品,主攻创名牌和保护名牌;农产品加工业要按照农业产业化经营模式发展;改制是公有制农产品加工企业必须解决的重大课题;转变政府职能和实行必要的宏观调控是农产品加工业适应市场需要发展所必须的条件。     

Clade 2.3.4.4 avian influenza A (H5N8) outbreak in commercial poultry,Iran, 2016: the first report and update data

Tropical Animal Health and Production - In 2010, H5N8 highly pathogenic avian influenza (HPAI) viruses of the A/Goose/Guangdong/1/1996 lineage dramatically affected poultry and wild birds in Asia,...     

Sampling procedure simulating on‐the‐go sensing for soil nutrients

The emergence of a new sensor technology based on the use of ion‐selective membranes provides an increasing number of opportunities for on‐the‐go field measurements of soil nutrients and soil pH. In the future, on‐the‐go sensing should provide a cost‐effective monitoring of heterogeneous soils with high sampling resolution. It is suitable for site‐specific management because it can be focused on the spatial representativity of observation. This study evaluates the on‐the‐go‐sensing sampling design by comparing it with a standard approach to soil sampling for soil pH and the base nutrients P, K, and Mg under local field conditions in Germany. Soil samples were taken in two test sites at a resolution and in a manner as if they were sampled with an on‐the‐go sensing system and were compared with soil samples taken at a coarser resolution and with standard methods. In general, a higher variability was observed among the on‐the‐go samples due to their smaller sample support. The finer sampling resolution of the on‐the‐go design improved field‐scale semivariogram‐analysis results, identifying the spatial structures for soil pH, P, and Mg clearly. In addition, kriged maps of these soil parameters had predominantly higher estimation accuracies. However, the on‐the‐go samples were strongly influenced by the small‐scale variability of K in one of the test sites. This variability increased the kriging standard deviation for K by 50% compared with standard sampling design. Despite of this problem, the on‐the‐go‐sensing sampling design revealed field‐scale spatial variability for base nutrient status more accurately. Except for K, the mean absolute error of fertilizer‐application maps was reduced when using the on‐the‐go sample design in comparison with the standard sample design (Ca: 210/268 kg ha^–1, P: 2.85/6.75 kg ha^–1, K: 13.7/6.0 kg ha^–1, Mg 5.7/6.8 kg ha^–1). This will reduce over‐ and underfertilization using variable‐rate fertilizer‐application systems. In the future, it will be of interest if real on‐the‐go soil‐sensor measurements exhibit the same variability behavior addressed here or if results will differ substantially.     

Exercise induced hypercoagulability,increased von Willebrand factor and decreased thyroid hormone concentrations in sled dogs

Background

Sled dogs performing endurance races have been reported to have a high incidence of gastric erosions or ulcerations and an increased risk of gastro intestinal bleeding leading to death in some cases. In addition, these dogs also become hypothyroid during training and exercise. Canine hypothyroidism has been shown to correlate with decreased von Willebrand factor antigen and potentially increased bleeding tendency. Whether increased gastro intestinal bleeding risk is exacerbated due to changes in the hemostatic balance is unknown. The aim of this study was to investigate the hemostatic balance in sled dogs before and after exercise and in addition evaluate any correlation to thyroid status. Twenty sled dogs have been assessed in untrained and trained condition and immediately after exercise. The first sample was collected in the autumn following a resting period, and subsequently the dogs were exposed to increased intensity of training. After four months the peak of physical condition was reached and a 68 km long sled pulling exercise was performed. Samples were collected before and immediately after the exercise. Evaluated parameters were: plasma thromboelastographic (TEG) R, SP, α and MA, activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, von Willebrand factor (vWf), D-dimer, platelet number, thyroid hormones, hematocrit and C-reactive protein (CRP).

Results

Exercise induced an overall hypercoagulable state characterized by significant decreases of TEG R and SP and an increase of α, increased concentrations of plasma vWf and decreased aPTT. In addition, a proinflammatory status was seen by a significant increase of serum CRP concentrations. Thyroid status was confirmed to be hypothyroid as training and exercise induced significant decrease of thyroxin (T4), free thyroxin (fT4) and thyroxin stimulating hormone (TSH) concentrations. Fibrinogen decreased significantly and PT increased. The training-induced changes showed correlation between T4, fT4 and aPTT and correlation between TSH and fibrinogen. Exercise-induced changes showed correlation between T4 and PT.

Conclusions

Exercise was associated with a hypercoagulable state and an increase of vWf concentration in this group of sled dogs. Decreased thyroid hormone concentrations after training and exercise were confirmed, but were associated with increased and not decreased vWf in this group of sled dogs.     

Comparative histopathological study of the canine thyroid gland in London and Munich

The thyroid glands of two series of ninety-nine unselected dogs from consecutive autopsies in London and in Munich were examined histologically. The prevalence of goitre and of neoplasia was distinctly higher in dogs in the Munich series.
Résumé. On a examiné de façon histologiyue les glandes thyroïdes de deux séries de quatrevingt-dix-neufs chiens d'après des autopsies consécutives à Londres et à Munich. La prédominance de goîtres et de néoplasie était nettement plus élevée chez les chien de la série de Munich
Zusammenfassung. Die Schilddrüsen von zwei Serien von 99 Hunden Wurden von darauf-folgenden Autopsien in London und München histologisch untersucht. Das Vorkommenwon Kropf und Neoplasia war entschieden höher in den Hunden der Munchener Serie.