Root initiation of Shorea macrophylla cuttings: Effects of node position,growth regulators and misting regime

Single-node leafy cuttings from 8- and 15-month-old seedlings of the large Bornean Dipterocarp Shorea macrophylla (Illipe nut) rooted easily under continuous mist, both with and without the application of auxins. Callus production was greatest in the untreated cuttings. Rate of rooting was enhaced by 1200 ppm and 3600 ppm IBA, but the overall level of rooting after 61 days was unaffected by auxin treatment. In a second experiment, 3600 ppm IBA was found to be more effective than 3600 ppm NAA and mixtures of 1800 ppm NAA + 1800 ppm IBA. Mortality of cuttings was greatest with IBA especially at 10800 ppm. Cuttings from the second node below the apex rooted best, with rooting ability of those from nodes 3, 4 and 5 being progressively worse, and mortalities rising with distance from the apex. Cuttings from the uppermost node, which included the developing apex, had the lowest rooting ability. When continuous misting was replaced with misting for alternate hours, rooting was still good, but the absence of misting overnight resulted in much increased cutting mortality and, subsequently, in decreased rooting. It is suggested that Shorea macrophylla could be domesticated for fruit or timber production by the propagation of superior clones.     

温室白粉虱防治试验的探讨

温室白粉虱(Trialeurodes vaporarioum Westwoad)是园艺植物的重要害虫,自1975年在北京地区各种温室、塑料大棚、露地等作物上大发生以来,已成为蔬菜生产和花卉栽培急待解决的生产问题。为了寻找有效的防治方法,我们在研究了温室白粉虱生物学     

Estimating the number of undetected multi-resistant Salmonella Typhimurium DT104 infected pig herds in Denmark

In Denmark, the detection of multi-resistant Salmonella Typhimurium DT104 (MRDT104)-infected pig herds relies on the national Salmonella surveillance programme at the farm and slaughterhouse levels of production. With the surveillance sampling protocol and the diagnostic methods currently used, some herds might remain undetected. The number of undetected Danish pig herds infected with MRDT104 in the period 1 August 2001–31 July 2002 was estimated and compared with the number of culture-confirmed detected herds. A flow chart was constructed to illustrate where infected herds will go undetected in the surveillance system and Monte Carlo simulation was used to model the actual number of pig herds infected with MRDT1104. We estimated that 52 (90% CI [28, 178]) finisher herds were infected with MRDT104 compared to 23 (44%) detected. Among sow herds with production of weaners or growers, we estimated that 38 (90% CI [23, 74]) were infected with MRDT104 compared to 7 (18%) actually detected. Among breeder and multiplier herds, we estimated that five (90% CI [3, 8]) herds were infected with MRDT104 compared to three (60%) detected. In total, we estimated that 102 pig herds were infected with MRDT104 from 1 August 2001 till 31 July 2002 (90% CI [63, 228]). In comparison, 33 (32%) infected herds were detected in this period. The predicted proportion of undetected herds varied considerably with herd type. We infer that the proportion of detected MRDT104 infected herds depended on the intensity of the combined serological and bacteriological testing.     

柑桔黄梢(黄龙)病热治疗的初步研究

已經发生黄梢病的2年生椪柑嫁接苗,經湿热空气48°、49°及50℃处理31、35及40分钟后定植,大部分可恢复健康。一小部分起初生长正常,但8个月后仍发病。恢复健康的树一部分后来又受侵染,21个月后重新发病。其余的则始終保持健康。已經发生黄梢病的3年生蕉柑树,经湿热空气48°、49°、50℃分别处理45、50、55、60、65分钟和51℃处理35、40、45、50、55分钟后重植,全部恢复健康,迄今(28个月后)未見一株发病。試驗結果说明带有黄梢病毒的接穗芽条和苗木,經48°—51℃的湿热空气处理45—60分钟后,均可能成为安全的繁殖或种植材料。经适当高温处理后的椪柑病苗,绝大部分从主干基部或中部抽出徒长梢,一部分还从砧木长出徒长梢。一部分蕉柑病树经热处理后也同样长出徒长梢。这些徒长梢生长迅速,很快就超过原来主干顶部枝梢的高度,有的到第二年还可开花結实。说明热处理对柑桔类的組織有一定刺激生长作用。且不影响开花結果。     

Clusters of coupled neuroblasts in embryonic neocortex.

The neocortex of the brain develops from a simple germinal layer into a complex multilayer structure. To investigate cellular interactions during early neocortical development, whole-cell patch clamp recordings were made from neuroblasts in the ventricular zone of fetal rats. During early corticogenesis, neuroblasts are physiologically coupled by gap junctions into clusters of 15 to 90 cells. The coupled cells form columns within the ventricular zone and, by virtue of their membership in clusters, have low apparent membrane resistances and generate large responses to the inhibitory neurotransmitter gamma-aminobutyric acid. As neuronal migration out of the ventricular zone progresses, the number of cells within the clusters decreases. These clusters allow direct cell to cell interaction at the earliest stages of corticogenesis.     

An alternative solution for the determination of elastic parameters in free–free flexural vibration of a Timoshenko beam

An alternative inversion solution is presented to compute the elastic parameters based on the Timoshenko equation of motion in free flexural vibration. The interest of this solution was its relatively simple formulation and its validity domain, which was not restricted to the initial frequencies and a certain range of length-to-height ratio. The uniqueness of the solution was verified numerically, and the best optimization strategy was deduced. It was underlined that the shear modulus determination depended on the length-to-height ratio coupled with the number of resonance frequencies involved in the computation. The accuracy of the computed elastic modulus values was in the same scale as that for the measurement errors of frequency. However, the sensitivity of the shear modulus was found to be very high and depended on the number of frequencies taken into account. The theoretical model was found to be more accurate and to better estimate the frequency values than a classic solution of the Timoshenko equation. Furthermore, the inversion procedure gave equivalent elastic property values to those obtained with a classic solution (in the validity range of the classic solution) and was more robust when the number of frequencies taken into account was low.     

Survey of the prevalence, diagnosis and treatment of dermatological conditions in small animals in general practice

A survey was made of the prevalence, diagnosis and treatment of dermatological conditions in small animals in general practice in the UK. Out of 3707 small animal consultations in general practice that were observed and recorded, 795 (21.4 per cent) involved animals that had a dermatological problem. In dogs and exotic species, pruritus was the most common presenting sign, accounting for 30 to 40 per cent of the dermatological consultations. In cats, cutaneous swellings were the most common presentation (36 per cent). A diagnosis or recommendation for treatment was made on the basis of the presenting clinical signs and physical examination alone in 576 (72 per cent) of the cases, and various diagnostic tests were performed in the other cases. In dogs, parasitic infestations, bacterial infections and neoplasia accounted for the majority of the diagnoses. In cats, parasites and bacterial infections were the most common. In exotic species, parasites accounted for over 80 per cent of the dermatological diagnoses. In dogs, the most common final diagnoses were otitis, pyoderma, anal sac impaction, flea infestation and atopic dermatitis. In cats, abscesses, flea infestation, and otitis were the most common diagnoses. In exotic species, the most common diagnosis was an unspecified mite infestation. Systemic antibiotics were prescribed in 196 cases (25 per cent), systemic glucocorticoids were prescribed in 162 cases (20 per cent) and treatment with an ectoparasiticide was prescribed in 167 cases (21 per cent).