The behaviour of a population of honeybees on an artificial and on a natural crop

One hundred and twelve Petri dishes filled with sugar syrup were arranged at 20 yd. intervals from each other in a meadow. Individual bees were observed to visit one chosen dish with great regularity for one or more days, provided that the supply did not become exhausted. Occasionally bees maŕked on one dish were observed to visit an adjacent dish. This occurred most frequently when the supply of syrup temporarily failed at the original site of feeding, but, even after a 3-day interruption in the syrup supply bees often returned to feed at the original site. Bees feeding at a dish full of syrup spent only a fraction of their time (about 1 min.) per visit drinking, but several times as long flying to and from the hive and delivering their load. When the supply of syrup in a dish became exhausted all the bees accustomed to visit that dishgradually accumulated there impatiently seeking for food; after some minutes they extended their radius of search, and many located another source near at hand. Thereafter they visited either the new source or the old, or both, when the syrup at the original site was replenished. The nearer such a new source was to the original one the more likely a bee was to find it; a dish 20 yd. away from the original site was quickly found despite the fact that such a second dish would seldom be visited if the syrup at the original site was constantly maintained. Bees were deterred from collecting syrup from dishes placed even partially in shade; they veryseldom worked beneath the shade of trees. There were even some indications that they prefered not to fly in the direction of shady trees. Over the range of distances covered (160-400 yd.) there were always more visitors to the nearer than to the more distant dishes. The extent of this difference, however, varied from day to day. Bees accustomed to collect syrup from the dishes farthest from the hive did not move to sites nearer home when the weather became unfavourable. There was some evidence, however, that bees working a long way away from the hive were more easily deterred, from foraging by unfavourable weather than those working close to the apiary. When two different concentrations of syrup were offered in different groups of dishes simultaneously the number of visitors to the dishes containing the syrup of high concentration rose considerably higher than that of the visitors to the dishes containing low-concentration syrup; even after all the dishes had been refilled with syrup of uniform concentration on the following day, this difference remained noticeable. Bees marked on a patch of willow-herb (Epilobium angustifolium) situated in the midst of a large crop of this plant, were usually recovered within 5 yd. of the point of marking. Such bees remained ‘fixed’ to this area for several days. Observations were made upon isolated patches of the cultivated thistle; Echinops sphaerocephalus, of bees which continued to visit the patches upon which they were marked for periods up to 16 days. The majority of the bees working the patches showed great constancy: and of such regular visitors the percentage per day observed to stray to other patches of Echinops 18 yd. away was comparatively small. The time spent by foraging bees upon the flowerheads of Echinops on any one visit greatly exceeded the time spent in collecting syrup from a dish (20-60 min. as against 1 min.); but the time spent in flying between the hive and the flowers, or dish, and unloading was approximately equal in each case. Only a small proportion of the population of bees working on a particular dish could be found feeding there at any one time, whereas on a patch of flowering plants, under good weather conditions, most of the population visiting that patch would be found there at any one time. This great difference in behaviour on dishes as compared with plants must be borne in mind in any attempt to draw conclusions from dish experiments as to the behaviour of bees

Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions

Background Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals. Results Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall. Conclusions The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions

LUMOS - Low and Intermediate Grade Glioma Umbrella Study of Molecular Guided TherapieS at relapse: Protocol for a pilot study

IntroductionGrades 2 and 3 gliomas (G2/3 gliomas), when combined, are the second largest group of malignant brain tumours in adults. The outcomes for G2/3 gliomas at progression approach the dismal outcomes for glioblastoma (GBM), yet there is a paucity of trials for Australian patients with relapsed G2/3 gliomas compared with patients with GBM. LUMOS will be a pilot umbrella study for patients with relapsed G2/3 gliomas that aims to match patients to targeted therapies based on molecular screening with contemporaneous tumour tissue. Participants in whom no actionable or no druggable mutation is found, or in whom the matching drug is not available, will form a comparator arm and receive standard of care chemotherapy. The objective of the LUMOS trial is to assess the feasibility of this approach in a multicentre study across five sites in Australia, with a view to establishing a national molecular screening platform for patient treatment guided by the mutational analysis of contemporaneous tissue biopsiesMethods and analysisThis study will be a multicentre pilot study enrolling patients with recurrent grade 2/3 gliomas that have previously been treated with radiotherapy and chemotherapy at diagnosis or at first relapse. Contemporaneous tumour tissue at the time of first relapse, defined as tissue obtained within 6 months of relapse and without subsequent intervening therapy, will be obtained from patients. Molecular screening will be performed by targeted next-generation sequencing at the reference laboratory (PathWest, Perth, Australia). RNA and DNA will be extracted from representative formalin-fixed paraffin embedded tissue scrolls or microdissected from sections on glass slides tissue sections following a review of the histology by pathologists. Extracted nucleic acid will be quantified by Qubit Fluorometric Quantitation (Thermo Fisher Scientific). Library preparation and targeted capture will be performed using the TruSight Tumor 170 (TST170) kit and samples sequenced on NextSeq 550 (Illumina) using NextSeq V.2.5 hi output reagents, according to the manufacturer’s instructions. Data analysis will be performed using the Illumina BaseSpace TST170 app v1.02 and a custom tertiary pipeline, implemented within the Clinical Genomics Workspace software platform from PierianDx (also refer to section 3.2). Primary outcomes for the study will be the number of patients enrolled and the number of patients who complete molecular screening. Secondary outcomes will include the proportion of screened patients enrolled; proportion of patients who complete molecular screening; the turn-around time of molecular screening; and the value of a brain tumour specific multi-disciplinary tumour board, called the molecular tumour advisory panel as measured by the proportion of patients in whom the treatment recommendation was refined compared with the recommendations from the automated bioinformatics platform of the reference laboratory testing.Ethics and disseminationThe study was approved by the lead Human Research Ethics Committee of the Sydney Local Health District: Protocol No. X19-0383. The study will be conducted in accordance with the principles of the Declaration of Helsinki 2013, guidelines for Good Clinical Practice and the National Health and Medical Research Council National Statement on Ethical Conduct in Human Research (2007, updated 2018 and as amended periodically). Results will be disseminated using a range of media channels including newsletters, social media, scientific conferences and peer-reviewed publications.Trial registration numberACTRN12620000087954; Pre-results.</jats:sec

A comparison of the clinical effectiveness and cost of specialised individually-delivered parent training for preschool attention-deficit/hyperactivity disorder and a generic, group-based programme: a multi-centre, randomised controlled trial of the New Forest Parenting Programme versus Incredible Years

Objective: To compare the efficacy and cost of specialised individually-delivered parent training (PT) for preschool children with attention-deficit/ hyperactivity disorder (ADHD) against generic group-based PT and treatment as usual (TAU). Design: Multi-centre, three-arm parallel group randomised controlled trial. Research Setting: National Health Service Trusts. Participants: Preschool children (33-54 months) fulfilling ADHD research diagnostic criteria. Interventions: New Forest Parenting Programme (NFPP) – 12 week individual, home-delivered ADHD PT programme; Incredible Years (IY) – 12 week group-based, PT programme initially designed for children with behaviour problems. Main outcome measures: Primary outcome - Parent ratings of child’s ADHD symptoms (Swanson, Nolan & Pelham Questionnaire - SNAP-IV). Secondary outcomes - teacher ratings (SNAP-IV) and direct observations of ADHD symptoms and parent/teacher ratings of conduct problems. NFPP, IY and TAU outcomes were measured at baseline (T1) and post-treatment (T2). NFPP and IY outcomes only were measured 6 months post treatment (T3). Researchers, but not therapists or parents, were blind to treatment allocation. Analysis employed mixed effect regression models (multiple imputation). Intervention and other costs were estimated using standardized approaches. Results: NFPP and IY did not differ on parent-rated SNAP-IV, ADHD combined symptoms (mean difference -0.009 95%CI [-0.191, 0.173], p=0.921) or any other measure. Small, non-significant, benefits of NFPP over TAU were seen for parent-rated SNAP-IV, ADHD combined symptoms (-0.189 95%CI [-0.380, 0.003], p=0.053). NFPP significantly reduced parent-rated conduct-problems compared to TAU across scales (p-values.05). The cost per family of providing NFPP in the trial was significantly lower than IY (£1,591 versus £2,103). Conclusions: Although, there were no differences between NFPP and IY with regards clinical effectiveness, individually-delivered NFPP cost less. However, this difference may be reduced when implemented in routine clinical practice. Clinical decisions should take into account parental preferences between delivery approaches. Funding: National Institute of Health Research. Trial Registration: Trial name: COPPI Trial; ISRCTN39288126