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Women make up over one-half of all doctoral recipients in biologyrelated fields but are vastly underrepresented at the faculty level in the life sciences. To explore the current causes of women's underrepresentation in biology, we collected publicly accessible data from university directories and faculty websites about the composition of biology laboratories at leading academic institutions in the United States. We found that male faculty members tended to employ fewer female graduate students and postdoctoral researchers (postdocs) than female faculty members did. Furthermore, elite male faculty-those whose research was funded by the Howard Hughes Medical Institute, who had been elected to the National Academy of Sciences, or who had won a major career award-trained significantly fewer women than other male faculty members. In contrast, elite female faculty did not exhibit a gender bias in employment patterns. New assistant professors at the institutions that we surveyed were largely comprised of postdoctoral researchers from these prominent laboratories, and correspondingly, the laboratories that produced assistant professors had an overabundance of male postdocs. Thus, one cause of the leaky pipeline in biomedical research may be the exclusion of women, or their self-selected absence, from certain high-achieving laboratories. etween 1969 and 2009, the percentage of doctorates awarded to women in the life sciences increased from 15% to 52% (1, 2). Despite the vast gains at the doctoral level, women still lag behind in faculty appointments. Currently, only 36% of assistant professors and 18% of full professors in biology-related fields are women (3). The attrition of women from academic careersknown as the leaky pipeline problem (4)-undermines the meritocratic ideals of science and represents a significant underuse of the skills that are present in the pool of doctoral trainees.A variety of factors has been suggested to influence the leaky pipeline in science, technology, engineering, and math (STEM) fields. Early career aspirations and choice of undergraduate major are significant departure points for women in certain disciplines (5, 6). For instance, women are awarded only 19% of bachelor's degrees in physics and 18% of bachelor's degrees in engineering, and correspondingly fewer women go on to graduate school in those subjects (1). In contrast, women are awarded >50% of both bachelor's and doctoral degrees in biology, suggesting that major leaks in the pipeline occur at later points in professional development. Gender differences in individuals' personal aspirations may explain some attrition from the academy (7). For instance, in surveys of graduate students and postdoctoral researchers (postdocs), women tend to rank work-life balance and parenthood-related issues as more important than men do, and the perceived difficulty of raising a family while working as a tenure-track faculty member causes more women than men to leave the academic pipeline (8-12). Such preferences are likely constrained by societal ...

S U M M A R YMore Brevicoryne brassicae and other alate aphids were caught in yellow water-traps in a weed-free crop of Brussels sprouts than in a crop with a weedy background. More B. brassicae colonized Brussels sprout plants in Present address: Departamento de Zoologia, Universidade Federal do Parand, Caixa postal 756, Curitiba 80.000, Parand, Brazil. 1-2 2 JUDITH G. SMITH Brevicoryne brassicae L., although other species of aphids and some other brassica pests (Aley~odes brassicae (Wlk.) and certain Lepidoptera) were also counted. Effects of background on natural enemies of aphids are described separately (Smith, 1969(Smith, ,1976.The work was part of a programme aimed at integrated control of insect pests on Brussels sprout plants, the manipulation of crop background being considered as a possible component of an integrated control practice. MATERIALS A N D M E T H O D S Field experimentsExperiments. Field experiments were done in a I-acre (0.4 ha) crop of Brussels sprouts (B~assic~ oleracea gemmifera L. cv. Irish Elegance) in Silwood Bottom at Imperial College Field Station, Silwood Park, Berkshire, between 1965 and 1967. Young plants were planted out during early June at spacings of 36 x 30 in (91 x 76 cm) (1965) or 36 x 36 in (1967); in 1966, plants were initially spaced at 36 x 18 in and thinned out in early August to 36 x 36 in. The 1965 experiment consisted of eight plots, each 210 yd2 (176 m2), of Brussels sprout plants, four kept weed-free by regular hoeing and four where the indigenous weeds were allowed to grow but were cut back regularly to about 6 in (IS cm) high;weeds growing immediately beneath sprout plants were removed. The experiment was laid out with two adjacent blocks of alternating weedy and weed-free plots. In a similar experiment in 1967, there were two weed-free and two weedy plots, each 120 yd2 ( IOO m2); in 1966 a 4 x 4 latin square was set up with weedy and weed-free plots, each 75 yd2 (63 m2), and with plots with artificially coloured green and brown backgrounds, formed by placing 3 ft (91 cm) wide strips of painted hessian between the rows of plants. A layer of straw beneath the hessian prevented it from being soiled in wet weather.In the years 1966 and 1967, dry weather delayed the germination of weeds and hence delayed establishment of the contrasting weedy or weed-free backgrounds. In early July, 0.02 yo (v/v) mevinphos in water was therefore applied to eliminate aphid colonies established before the backgrounds differentiated. Yellow and suction traps. Numbers of flying insects were assessed from July to November from catches in yellow water-traps 3-7 in (9-4 cm) in diameter, positioned at the centre of each plot and kept level with the heart and young leaves of the sprout plants; the traps were emptied three times a week.Catches of aphids and syrphids in four 9 in (23 cm) diameter suction traps (Johnson, 1950) which were operated in fine weather between July and September 1966, were compared in plots with different backgrounds.Plant samples. The outer row of each plot was di...

Distributed Drug Discovery (D3) proposes solving large drug discovery problems by breaking them into smaller units for processing at multiple sites. A key component of the synthetic and computational stages of D3 is the global rehearsal of prospective reagents and their subsequent use in the creation of virtual catalogs of molecules accessible by simple, inexpensive combinatorial chemistry. The first section of this article documents the feasibility of the synthetic component of Distributed Drug Discovery. Twenty-four alkylating agents were rehearsed in the United States, Poland, Russia, and Spain, for their utility in the synthesis of resin-bound unnatural amino acids 1, key intermediates in many combinatorial chemistry procedures. This global reagent rehearsal, coupled to virtual library generation, increases the likelihood that any member of that virtual library can be made. It facilitates the realistic integration of worldwide virtual D3 catalog computational analysis with synthesis. The second part of this article describes the creation of the first virtual D3 catalog. It reports the enumeration of 24 416 acylated unnatural amino acids 5, assembled from lists of either rehearsed or well-precedented alkylating and acylating reagents, and describes how the resulting catalog can be freely accessed, searched, and downloaded by the scientific community.