Thyroid cancer following scalp irradiation: a reanalysis accounting for uncertainty in dosimetry

In the 1940s and 1950s, over 20,000 children in Israel were treated for tinea capitis (scalp ringworm) by irradiation to induce epilation. Follow-up studies showed that the radiation exposure was associated with the development of malignant thyroid neoplasms. Despite this clear evidence of an effect, the magnitude of the dose-response relationship is much less clear because of probable errors in individual estimates of dose to the thyroid gland. Such errors have the potential to bias dose-response estimation, a potential that was not widely appreciated at the time of the original analyses. We revisit this issue, describing in detail how errors in dosimetry might occur, and we develop a new dose-response model that takes the uncertainties of the dosimetry into account. Our model for the uncertainty in dosimetry is a complex and new variant of the classical multiplicative Berkson error model, having components of classical multiplicative measurement error as well as missing data. Analysis of the tinea capitis data suggests that measurement error in the dosimetry has only a negligible effect on dose-response estimation and inference as well as on the modifying effect of age at exposure.     

Unconditional versions of several tests commonly used in the analysis of contingency tables

By focusing on a confidence interval for a nuisance parameter, Berger and Boos (1994, Journal of the American Statistical Association 89, 1012-1016) proposed new unconditional tests. In particular, they showed that, for a 2 x 2 table, this procedure generally was more powerful than Fisher's exact test. This paper utilizes and extends their approach to obtain unconditional tests for combining several 2 x 2 tables and testing for trend and homogeneity in a 2 x K table. The unconditional procedures are compared to the conditional ones by reanalyzing some published biomedical data.     

Demographic traits of Eotetranychus pruni from Belgian and Tunisian orchards,in comparison with Tetranychus urticae

Eotetranychus pruni was recorded in Belgian and Tunisian apple orchards for the first time. The aim of this study was to compare a Belgian (Vieusart) and a Tunisian strain (Grombalia), with respect to their life history and demographic traits. Furthermore, a Tunisian strain of Tetranychus urticae (Sousse) was also added to the study, in order to evaluate the potential status of the Tunisian strain of E.pruni. Experiments were carried out in the laboratory(24 °C) on apple leaf discs. Significant differences were noticed between the two species, with respect to development time (males),fecundity and fertility (egg hatching), but no differences could be detected between the two strains of E. pruni. Life tables were setup to describe the population statistics. The calculated intrinsic rates of natural increase (r _m) appear to be rather lowper se and do not correspond to those of typical “rstrategic pests”. The Bootstrap procedure allows us to estimate the confidence interval for these r _m values. By using this method, the two Tunisian strains (T. urticae and E. pruni) appear to be quite similar, and contrast with the Belgian strain (E. pruni). The potential pest status of the Tunisian strain of E. pruni is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Life tables of the predatory mite Phytoseiulus longipes feeding on Tetranychus evansi at four temperatures (Acari: Phytoseiidae, Tetranychidae)

The tomato red spider mite, Tetranychus evansi, is reported as a severe pest of tomato and other solanaceous crops from Africa, from Atlantic and Mediterranean Islands, and more recently from the south of Europe (Portugal, Spain and France). A population of the predaceous mite Phytoseiulus longipes has been recently found in Brazil in association with T. evansi. The objective of this paper was to assess the development and reproduction abilities of this strain on T. evansi under laboratory conditions at four temperatures: 15, 20, 25 and 30°C. The duration of the immature phase ranged from 3.1 to 15.4 days, at 30 and 15°C, respectively. Global immature lower thermal threshold was 12.0°C. Immature survival was high at all temperatures tested (minimum of 88% at 30°C). The intrinsic rate of increase (r _m) of P. longipes ranged from 0.091 to 0.416 female/female/day, at 15 and 30°C, respectively. P. longipes would be able to develop at a wide range of temperatures feeding on T. evansi and has the potential to control T. evansi populations.     

Host preference of Xanthopimpla stemmator (Hymenoptera: Ichneumonidae) and its reproductive performance on selected African lepidopteran stem borers

The Asian pupal parasitoid, Xanthopimpla stemmator Thunberg, was imported into East Africa as a classical biological agent of lepidopteran cereal stem borers. Preference of X. stemmator females for four common borers of maize and sorghum; the crambid Chilo partellus (Swinhoe), the pyralid, Eldana saccharina Walker, and the noctuids, Busseola fusca Fuller and Sesamia calamistis Hampson, was investigated. Pre-adult experience of X. stemmator females did not influence choice of host. In dual choice tests, more B. fusca were attacked than E. saccharina, while E. saccharina were attacked more than Ch. partellus. Life table studies on three of the hosts revealed that the intrinsic rate of increase was highest when X. stemmator was reared on S. calamistis. Net reproductive rates, mean generation times and doubling times were not different between hosts. Results suggest that X. stemmator can be successfully reared on the three stem borer species and released in areas where any combination of the three hosts occurs.     

苦豆子提取物与埃玛菌素混合剂剂对小菜蛾实验种群生长的影响

将苦豆子甲醇提取物和苦豆子水提取物分别与埃玛菌素混合,得到苦豆子甲醇提取物·埃玛菌素(简称苦醇·埃)和苦豆子水提取物·埃玛菌素(简称苦水·埃)2种混合剂,在室内用特定年龄生命表法,研究了2种混合剂低致死剂量对小菜蛾的影响,并对其F_1代幼虫、蛹以及成虫进行了观察。结果表明,埃玛菌素、苦醇·埃和苦水·埃3个处理对小菜蛾F_1代各龄期均有影响。其种群趋势指数(I)分别为6.23、4.81和5.70,而对照组种群趋势指数则为28.03。     

Sublethal effects of insecticides on the intrinsic rate of increase of cotton aphid

Insecticides are often implicated in causing outbreaks of the cotton aphid, Aphis gossypii (Glover) (Homoptera: Aphididae), through stimulation of reproduction. In this study we report the sublethal effects of dosages of bifenthrin, acephate, carbofuran or pyriproxifen on cotton aphid reproduction. We could not detect any increase or decrease in the intrinsic rate of increase of cotton aphids exposed to bifenthrin, acephate or carbofuran. However, we did detect some increases in the net reproductive rate of aphids treated with bifenthrin justifying further investigation of the effect on reproduction by this insecticide. Trends based on simple linear regression models suggest that sublethal dosages of bifenthrin or carbofuran have a negative impact on aphid population growth as dosages increase. These data suggest that stimulation of reproduction by these insecticides probably does not play a major role in cotton aphid outbreaks or resurgence. Pyriproxyfen is a juvenoid currently used for control of whiteflies in cotton. It demonstrated significant activity towards cotton aphid reared on treated cotton in our bioassays. Pyriproxyfen caused sterility in most aphids exposed to dosages exceeding 1 ppm, and reduced aphid longevity by approximately 50%. However, it did not appear to greatly influence the reproductive potential or longevity of reproductively mature aphids. A field study indicates that pyriproxyfen affects cotton aphid population structure and may have potential in managing cotton aphid outbreaks. Modifying aphid population structure and growth through the use of juvenoids such as pyriproxifen may prove to be an effective proactive approach to pest control without adversely impacting beneficial organisms or causing pest resurgence.     

两种猎物对南方小花蝽种群增长的影响及其对二斑叶螨的控害潜能

南方小花蝽(半翅目:花蝽科)是农田害虫的重要天敌之一。在室内,分别用米蛾卵和二斑叶螨饲养南方小花蝽,采用生命表与功能反应方法,探讨了两种猎物(米蛾卵、二斑叶螨)对南方小花蝽种群增长的影响、评价了南方小花蝽应用前景。南方小花蝽取食米蛾卵的年龄特征生命表的参数如下:世代平均历期T= 24.3500d,雌性比率P_♀=0.5250,单雌平均产卵量FP_F=37.2857头,种群趋势指数(I)=9.2118,周限增长率λ＝1.0955,内禀增长率r_m＝0.0912。取食二斑叶螨的南方小花蝽能完成发育,雌雄可交配,但不能产卵。一龄若虫的存活率为81.19%,低于其它龄期的若虫存活率(89.5%以上)。从初孵若虫至成虫死亡,平均历期为19.3716d。取食米蛾卵的南方小花蝽成虫存活率为83.33%,而取食二斑叶螨的成虫存活率为59.68%;取食米蛾卵的南方小花蝽若虫平均历期(11.0633d)短于取食二斑叶螨的(13.8950d);然而取食米蛾卵的南方小花蝽成虫平均历期(9.9750d)明显长于取食二斑叶螨的(5.7297d)。表明米蛾卵能够满足南方小花蝽生长发育的营养需求,可以用来室内饲养南方小花蝽,二斑叶螨室内不能单独用于饲养南方小花蝽。南方小花蝽成虫对二斑叶螨成螨捕食功能反应符合HollingⅡ模型,且处置时间Th=0.0108,瞬间攻击率a=0.8253,日最大捕食量Na_max =92.59 d^-1。南方小花蝽是二斑叶螨潜在的生物防治资材。     

Tabular strategies for metadata in ecology,evolution, and the environmental sciences

Data support knowledge development and theory advances in ecology and evolution. We are increasingly reusing data within our teams and projects and through the global, openly archived datasets of others. Metadata can be challenging to write and interpret, but it is always crucial for reuse. The value metadata cannot be overstated—even as a relatively independent research object because it describes the work that has been done in a structured format. We advance a new perspective and classify methods for metadata curation and development with tables. Tables with templates can be effectively used to capture all components of an experiment or project in a single, easy‐to‐read file familiar to most scientists. If coupled with the R programming language, metadata from tables can then be rapidly and reproducibly converted to publication formats including extensible markup language files suitable for data repositories. Tables can also be used to summarize existing metadata and store metadata across many datasets. A case study is provided and the added benefits of tables for metadata, a priori, are developed to ensure a more streamlined publishing process for many data repositories used in ecology, evolution, and the environmental sciences. In ecology and evolution, researchers are often highly tabular thinkers from experimental data collection in the lab and/or field, and representations of metadata as a table will provide novel research and reuse insights.     

Phenology,population ecology,and rarity of the New Zealand ribbonwood aphid,Paradoxaphis plagianthi

Abstract

We measured some aspects of the population ecology of an arboreal aphid, Paradoxaphis plagianthi, that might contribute to its rarity. Models were fitted to data on the development rate and variability of solitary aphids in the laboratory, from larviposition to maturity, which were similar to those of several common European tree‐dwelling aphids. Life tables suggested that the intrinsic rate of population increase increases linearly with temperature to a maximum of 0.123/day at 20°C. Aphid colonies raised in controlled environments showed a lower rate of increase, presumably due to crowding effects. The rate of increase of field colonies was further depressed, probably reflecting the action of other background mortality factors. New data for seasonal population trends in the field matched previously published results, showing an increase in spring followed by a rapid decline and low summer populations. A caging experiment failed to detect any differences in host suitability in late spring between Plagianthus regius, the main host, and Hoheria angustifolia or Parsonsia heterophylla, which may act as “spill‐over” hosts in some circumstances. While the results do not explain the rarity of P. plagianthi, they suggest new hypotheses to target future work.