Citric acid extraction—An underestimated method in forest nutrition?

Since recent studies reveal citric acid to be favorable for estimating plant‐available P in soils, we investigated if it can also be used for assessing other nutrients. According to our results, it provides stronger correlations with the tree nutrition for Mg (beech, spruce), Ca+K (beech) and Fe (spruce) than the standard methods for determining exchangeable cations. Thus, when estimating plant‐available P by citric acid‐extraction, these cations should be additionally measured in ICP analysis.     

Experimental infection of domestic pigeons with pigeon circovirus

Pigeon circovirus (PiCV) infection and young pigeon disease syndrome (YPDS), associated with high morbidity and mortality, have been recognized in young racing pigeons from large portions of Central Europe. There exist a number of data indicating that YPDS is a consequence of PiCV infection and subsequent immunosuppression. In order to prove PiCV to be one of the crucial factors of YPDS, an experimental infection with PiCV was performed under controlled conditions. Twenty-four domestic pigeons (Columba livia forma domestica) were divided into two groups with 12 pigeons each; an infection group and a control group. All birds were between their fourth to eighth week of life. Pigeons in the infection group were infected both intramuscularly and orally with PiCV purified from naturally infected birds, while pigeons in the control group received a placebo. To test a possible influence of the PiCV infection on the immune system, the animals in both groups were vaccinated simultaneously, on the same day, against PMV-1 (Lasovac plus, IDT, Dessau-Tornau, Germany). Weekly virologic testing showed a viraemic period, and excretion of the infection virus, in pigeons in the infection group. Replication of PiCV could be proved on the basis of histologic findings of multiglobular inclusion bodies, mainly observed in macrophages of the bursa of Fabricius. A PiCV, genetically distinct from the experimental virus, was detected in the control group by polymerase chain reaction (PCR) testing, but any histologic findings comparable to the infection group were absent. None of the pigeons revealed clinical signs of illness, or hints that immunosuppression had occurred, regardless of their group. The absence of stressful conditions, considered as a trigger for the development of YPDS, may be responsible for the failure of disease reproduction in our infection model.     

The Relationship between Linear Type Traits and Fertility Traits in High‐yielding Dairy Goats

Reproductive data collected from 13 medium‐size goat farms in central Mexico (582 goats), were used to investigate if linear type traits influenced reproductive performance of high‐yielding dairy goats. Data were analysed using multiple stepwise forward logistic regressions. Goats with the higher scores for strength were 1.43 times more likely (p < 0.05) to have larger litters (1.49 vs 1.39) than goats with lower strength. Goats approaching level rump angles were 1.68 times more likely (p < 0.01) to have larger litters, compared with goats with extremely sloped rump angles (1.48 vs 1.37). Goats with rear legs nearly straight (posty) in hock tended (p < 0.08) to presented larger litters than goats with rear legs slightly angled (sickled) in hock (1.49 vs 1.38). Less pronounced rump angle was favourable associated (p < 0.05) with litter weight (4.88 vs 4.53 kg) compared with goats with low pin bones. Goats with poorer udder texture were 1.42 more likely (p < 0.05) to have heavier litters than goats with good udder texture. Goats with faulty mammary system tended (p < 0.07) to have heavier litters than goats with good mammary system. Increasing udder height was associated (p < 0.05) with increasing number of services per conception. Goats with good fore udder attachment and non‐refined heads were at reduced risk (p < 0.05) for stillbirths. Goats with stronger median ligament were 65% less likely (p < 0.05) to lose their foetuses than those with looser udder support. Our findings indicate that a greater litter size and litter weight is expected in goats as rump angle becomes less sloped. This study showed that a relationship exists between strength of goats and litter size, and that some traits linked to high milk yield were antagonist to some reproductive traits.     

麦二叉蚜唾液蛋白基因Sg1655时空表达谱及其抑制小麦防御反应的功能

为进一步明确麦二叉蚜Schizaphis graminum唾液蛋白Sg1655在调控小麦防御反应中的作用,基于麦二叉蚜唾液腺转录组数据,利用PCR技术克隆获取Sg1655开放阅读框,利用生物信息学软件对其序列进行分析;通过实时荧光定量PCR（real-time quantitative PCR,RT-qPCR）技术检测Sg1655在麦二叉蚜不同组织及不同龄期中的表达;利用细菌III型分泌系统将Sg1655导入到小麦叶片内,检测其瞬时表达对小麦胼胝质积累的影响。结果表明,Sg1655开放阅读框全长375 bp,编码125个氨基酸残基,N端1~21位为信号肽序列,预测蛋白分子量为14.90 kD。麦二叉蚜Sg1655氨基酸序列与玉米蚜Rhopalosiphum maidis同源序列相致性最高,为89.52%;麦二叉蚜Sg1655与玉米蚜同源序列聚为一个分支,亲缘关系最近。Sg1655在麦二叉蚜各组织中均有表达,其中在唾液腺中表达量最高,Sg1655在麦二叉蚜各个龄期均有表达,且在不同龄期之间无显著差异。小麦叶片内Sg1655瞬时表达可显著抑制小麦胼胝质积累,表明该蛋白可作为潜在效应子参与抑制小麦防御反应。     

Planted forests of the wet and dry tropics: their variety,nature, and significance

Planting trees in tropical countries is an increasingly important forestry activity. Although much attention has been paid, and rightly so, to rapid deforestation in the tropics, the contribution and role that planted forests can play are now at the center of policy and planning in most national forestry strategies. The changing emphasis from exploitative management of natural forests to managed natural forests and plantation forests, seen in temperate regions over the last 100 years, has been taking place in tropical countries largely over the last 20 years. In neither temperate nor tropical regions has this evolution finished.Planted forests will increasingly furnish wood resources that meet domestic wood needs and provide many environmental services. In this paper I seek to place in perspective the contribution that planted forests will make in the tropics. I emphasize (1) the wide variety of purposes that planted forests serve; (2) the sustainability of plantation silviculture; and (3) the overriding importance of due regard to people's participation. I am optimistic about the great value that planted forests, rightly used, can provide for a great many hard-pressed peoples across the tropics and beyond.     

Effect of dietary flax oil and hypobaric hypoxia on pulmonary hypertension and haematological variables in broiler chickens.

1. Three experiments were conducted with broiler chickens using hypobaric chambers and control pens, feeding diets containing 25 or 50 g flax oil/kg food or control diets with equivalent amounts of animal/vegetable (A/V) blend oil for 4 weeks. The effect of these diets on haematological variables and the extent of right ventricular hypertrophy (RVH) leading to ascites was determined. 2. Overall growth rate was not consistently affected by dietary treatment, although feeding the 25 g flax oil/kg diet reduced weight gain in week 4 of one experiment. Feeding the 50 g flax oil/kg diet but not the 25 g flax oil/kg diet reduced RVH in birds exposed to hypobaric conditions compared to feeding control diets. 3. Feeding the 50 g flax oil/kg diet under hypobaric conditions reduced the haematocrit and haemoglobin content, increased the erythrocyte deformability and the proportion of unsaturated fatty acids in the erythrocyte membranes, and reduced the whole blood viscosity compared to feeding control diets. These effects were not seen when the 25 g flax oil/kg diet was fed. The ratio of n-3 to n-6 fatty acids in erythrocyte membranes was increased in the 50 g flax oil/kg treatment group compared to controls. 4. Including 50 g flax oil/kg broiler diet reduces RVH in broiler chickens. This may be attributable in part to an increase in erythrocyte deformability from an increased proportion of unsaturated fatty acids in the erythrocyte membranes.     

Habitat characterization,anthropogenic impacts and conservation of rhodolith beds off southeastern Malta

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Bonga shad (Ethmalosa fimbriata) spawning tactics in an upwelling environment

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Pesticide diversity in rice growing areas of Northern Vietnam

Pesticide use in developing countries increases rapidly. In many regions, we miss knowledge of how frequently pesticides are applied and which active ingredients are used. We present a new cost-efficient and rapid assessment method of recording pesticides diversity in rice-dominated landscapes and present some evidence of the misuse of active ingredients in our study regions. We investigated 17 rice fields in two regions of Northern Vietnam in 2014 and 2015. At each region, we explore the abundance of pesticides used with three methods including (1) the novel approach of collecting pesticide packages close to our target rice fields, (2) observations of farmers spraying pesticides in the surrounding and (3) interviewing local farmers. By collecting pesticide packages, we found 811 packages containing 74 different active ingredients. On average, 19 active ingredients (ranging from four to 40 active ingredients) were applied with an average content of 275.3 g of active ingredients per site. Insecticide packages (39%) were most abundant followed by those of fungicides (31%), herbicides (16%) and other active ingredients (14%). On all sites, active ingredients banned in the European Union were applied by the farmers. Collecting pesticide packages proved to be an efficient and rapidly implemented method to obtain some baseline information about pesticide application (for Northern Vietnam). We suspect that improved agricultural extension services could contribute to good agricultural practices in pest management. Generally, better information and education for local farmers for appropriate use of pesticides seem a necessity.     

Early life history connectivity of Antarctic silverfish (Pleuragramma antarctica) in the Ross Sea

A recent population hypothesis for Antarctic silverfish (Pleuragramma antarctica), a critical forage species, argued that interactions between life history and circulation associated with glacial trough systems drive circumpolar distributions over the continental shelf. In the Ross Sea, aggregations of eggs and larvae occur under fast ice in Terra Nova Bay, and the hypothesis predicted that dispersing larvae encounter outflow along the western side of Drygalski Trough. The outflow advects larvae towards the shelf‐break, and mixing with trough inflow facilitates return toward the inner shelf. To examine the hypothesis, we compared samples of P. antarctica collected near Coulman Island in the outflow, along Crary Bank in the inflow, and a third set taken over the rest of the Ross Sea. We ruled out misidentification using an innovative genetic validation. Silverfish larvae comprised 99.5% of the catch, and the highest population densities were found in Drygalski Trough. The results provided no evidence to reject the population hypothesis. Abundance indices, back‐calculated hatching dates, length distributions and growth were congruent with a unified early life history in the western Ross Sea, constrained by cryopelagic early stages in Terra Nova Bay. By contrast, a sample in the Bay of Whales revealed much smaller larvae, suggesting either a geographically separate population in the eastern Ross Sea, or westward connectivity with larvae spawned nearby by fish sourced from troughs upstream in the Amundsen Sea. These results illustrate how hypotheses that integrate population structure with life history can provide precise spatial predictions for subsequent testing.