Front crawl stroke in swimming: Phase durations and self-similarity

Human movements, such as walking and running, are able to generate rhythmic motor patterns, with the consequent appearance of hidden time-harmonic structures. Such harmonic structures are represented (at comfortable speed) by the occurrence of the golden ratio as ratio of durations of specific walking and running gait sub-phases. Preliminary experimental evidences suggest that front crawl swimming may behave, under this point of view, like walking and running. This paper aims to demonstrate that a mathematical connection between the golden ratio and the front crawl swimming stroke actually exists, at a pace that plays the role of the comfortable speed in walking and running. Generalized Fibonacci sequences are used to this purpose. They rely on the durations of aggregate phases of the front crawl swimming stroke with a clear physical meaning, while characterizing self-similarity of front crawl strokes in its simple nature and enhanced (stronger) variant. Experimental data on front crawl swimmers illustrate the theoretical derivations, suggesting that the pace playing the role of the comfortable speed in walking and running is the middle/long-distance one, while showing that the self-similarity level increases with the swimming technique and the enhanced self-similarity is associated with the performance of top-level swimmers.

Guide to managing persistent upper gastrointestinal symptoms during and after treatment for cancer

BACKGROUND

Guidance: the practical management of the gastrointestinal symptoms of pelvic radiation disease was published in 2014 for a multidisciplinary audience. Following this, a companion guide to managing upper gastrointestinal (GI) consequences was developed.

AIMS

The development and peer review of an algorithm which could be accessible to all types of clinicians working with patients experiencing upper GI symptoms following cancer treatment.

METHODS

Experts who manage patients with upper GI symptoms were asked to review the guide, rating each section for agreement with the recommended measures and suggesting amendments if necessary. Specific comments were discussed and incorporated as appropriate, and this process was repeated for a second round of review.

RESULTS

21 gastroenterologists, 11 upper GI surgeons, 9 specialist dietitians, 8 clinical nurse specialists, 5 clinical oncologists, 3 medical oncologists and 4 others participated in the review. Consensus (defined prospectively as 60% or more panellists selecting 'strongly agree' or 'agree') was reached for all of the original 31 sections in the guide, with a median of 90%. 85% of panellists agreed that the guide was acceptable for publication or acceptable with minor revisions. 56 of the original 61 panellists participated in round 2. 93% agreed it was acceptable for publication after the first revision. Further minor amendments were made in response to round 2.

CONCLUSIONS

Feedback from the panel of experts developed the guide with improvement of occasional algorithmic steps, a more user-friendly layout, clearer time frames for referral to other teams and addition of procedures to the appendix.

Evarcha culicivora chooses blood-fed Anopheles mosquitoes but other East African jumping spiders do not

Previous research using computer animation and lures made from dead prey has demonstrated that the East African salticid Evarcha culicivora Wesolowska & Jackson (Araneae: Salticidae) feeds indirectly on vertebrate blood by actively choosing blood-carrying female mosquitoes as prey, and also that it singles out mosquitoes of the genus Anopheles (Diptera: Culicidae) by preference. Here, we demonstrate that E. culicivora's preference is expressed when the species is tested with living prey and that it is unique to E. culicivora. As an alternative hypothesis, we considered the possibility that the preference for blood-fed female anopheline mosquitoes might be widespread in East African salticids. When live-prey choice tests were carried out in 19 additional species, there were no instances in which blood-carrying mosquitoes were chosen significantly more often than other prey. Combined with the findings of previous work, these results suggest that it is possible that specialized predators play a role in the biological control of disease vectors.

Convergent evolution of eye ultrastructure and divergent evolution of vision-mediated predatory behaviour in jumping spiders

All jumping spiders have unique, complex eyes with exceptional spatial acuity and some of the most elaborate vision-guided predatory strategies ever documented for any animal of their size. However, it is only recently that phylogenetic techniques have been used to reconstruct the relationships and key evolutionary events within the Salticidae. Here, we used data for 35 species and six genes (4.8 kb) for reconstructing the phylogenetic relationships between Spartaeinae, Lyssomaninae and Salticoida. We document a remarkable case of morphological convergence of eye ultrastructure in two clades with divergent predatory behaviour. We, furthermore, find evidence for a stepwise, gradual evolution of a complex predatory strategy. Divergent predatory behaviour ranges from cursorial hunting to building prey-catching webs and araneophagy with web invasion and aggressive mimicry. Web invasion and aggressive mimicry evolved once from an ancestral spartaeine that was already araneophagic and had no difficulty entering webs due to glue immunity. Web invasion and aggressive mimicry was lost once, in Paracyrba, which has replaced one highly specialized predation strategy with another (hunting mosquitoes). In contrast to the evolution of divergent behaviour, eyes with similarly high spatial acuity and ultrastructural design evolved convergently in the Salticoida and in Portia.

Discriminative feeding behaviour of Anopheles gambiae s.s. on endemic plants in western Kenya

Anopheles gambiae Giles s.s. (Diptera: Culicidae) is known to feed on plant sugars, but this is the first experimental study to consider whether it discriminates between plant species. Thirteen perennial plant species were selected on the basis of their local availability within the vicinity of human dwellings and larval habitats of An. gambiae s.s. in western Kenya. Groups of 100 or 200 mosquitoes were released into cages either with a cutting of one plant type at a time (single-plant assay) or with cuttings of all 13 plants simultaneously (choice assay), respectively, and left overnight. In the choice assay, direct observations of the percentages of mosquitoes perching or feeding on each plant were recorded over four 1-h periods each night. For both types of assay, mosquitoes were recaptured and the percentage that had fed on plants was assessed by testing them individually for the presence of fructose. To identify which plants the choice-assay mosquitoes had fed on, gas chromatography (GC) profiles of samples of mosquito homogenates were compared with GC profiles of extracts from relevant parts of each plant. Four of the plants that were observed to have been fed on most frequently in the choice assay (Parthenium hysterophorus L., Tecoma stans L., Ricinus communis L., and Senna didymobotrya Fresen) were also shown to have been ingested most often by mosquitoes in both types of assay, suggesting that An. gambiae is differentially responsive to this range of plants, regardless of whether the plants were presented singly or mixed together. Significantly more females than males fed on plants, with the exception of P. hysterophorus L., one of the plants most frequently fed on. For most plant species (ten of 13), GC profiles indicated that An. gambiae obtained sugars primarily from flowers. The exceptions were P. hysterophorus L., Lantana camara L. and R. communis L., on which An. gambiae fed more often from leaves and stems than from flowers.

Cues by which Portia fimbriata, an araneophagic jumping spider, distinguishes jumping-spider prey from other prey

Portia fimbriata from Queensland, Australia, is an araneophagic jumping spider (Salticidae) that includes in its predatory strategy a tactic (cryptic stalking) enabling it to prey effectively on a wide range of salticids from other genera. Optical cues used by P. fimbriata to identify the salticid species on which it most commonly preys, Jacksonoides queenslandicus, were investigated experimentally in the laboratory using odorless lures made from dead prey on which various combinations of features were altered. P. fimbriata adopted cryptic stalking only against intact salticid lures and modified lures on which the large anterior-median eyes were visible. Ordinary stalking was usually adopted when the lure did not have the anterior-median eyes visible. There was no evidence that cues from the legs of prey salticids influence the choice of stalking style of P. fimbriata, but cues from the legs do appear to influence strongly whether a prey is stalked at all. Cues from the cephalothorax and abdomen also influenced the stalking tendency, but to a lesser degree than cues from the legs. An algorithm to describe the perceptual processes of P. fimbriata when visually discriminating between salticid and non-salticid prey is discussed.

Predatory behavior of jumping spiders

Salticids, the largest family of spiders, have unique eyes, acute vision, and elaborate vision-mediated predatory behavior, which is more pronounced than in any other spider group. Diverse predatory strategies have evolved, including araneophagy, aggressive mimicry, myrmicophagy, and prey-specific prey-catching behavior. Salticids are also distinctive for development of behavioral flexibility, including conditional predatory strategies, the use of trial-and-error to solve predatory problems, and the undertaking of detours to reach prey. Predatory behavior of araneophagic salticids has undergone local adaptation to local prey, and there is evidence of predator-prey coevolution. Trade-offs between mating and predatory strategies appear to be important in ant-mimicking and araneophagic species.

A comparison of fast-rate, slow-rate, and silent previewing interventions on reading performance

Researchers investigated the effects of three different previewing interventions on the oral reading rates of 12 junior and senior high school students with learning disabilities. Under fast-rate listening previewing (FRLP), students were instructed to follow silently as experimenters read from a text at an average rate that was 77.7% faster than the students' current oral reading rate. During slow-rate listening previewing (SRLP), students followed along as experimenters read at an average rate that was 22.5% faster than the students' reading rate. Students were instructed to read passages silently under silent previewing (SP). Immediately following each previewing intervention, students read the same passage aloud. The number of words read correctly per minute and the number of errors per minute served as dependent variables. The results showed statistically significant decreases in error rates under SRLP and SP. The results also showed that SRLP resulted in statistically significantly fewer errors per minute than FRLP. These results suggest that orally reading while students follow along at a rate much higher than their current reading rates may not be as beneficial as reading aloud at slower rates.

Patient progress modelling for small cell lung cancer

This paper describes the use of a mathematical technique called Patient Progress Modelling to reassess the results of an MRC trial on small cell lung cancer. The trial concerned patients treated initially with chemotherapy and radiotherapy and achieving at least a partial response. It compared the effects of giving maintenance chemotherapy with those of giving no maintenance therapy. The results of the MRC trial established that there was no significant survival difference between the two groups overall. However, it was observed that amongst patients achieving a complete response, those receiving maintenance chemotherapy had a small survival time advantage. The analysis described here suggests the hypothesis that this can be accounted for by differences in the pattern of deaths after relapse. There appeared to be little difference in the disease-free period.

Reliability and consistency of bone marrow assessments of complete remission in acute myelogenous leukaemia

An experiment is described which was designed to investigate the level of variability in the assessment of bone marrow remission in Acute Myelogenous Leukaemia (AML). The inter-rater reliability and individual consistency of three haematologists at St Bartholomew's Hospital, London, are analysed using their assessments of cellularity, percent blast cells and marrow status for fifty bone marrow samples.

Towards an assessment of toxicity in the treatment of ovarian cancer

Using data from a randomised clinical trial of two platinum drugs at The Royal Marsden Hospital, London, a descriptive model of toxicity has been developed and tested. Toxicity manifests itself in reducing the effectiveness of different body processes; five were selected in this study as being most critical. The model summarises and combines data from these five sites in terms of a clinician's assessment of the associated risk to the patient. It is hoped that the approach will help clarify toxicity information for use in patient management decision-making and in the reporting of clinical trial results.

The Display Behavior of Bavia-Aericeps (Araneae, Salticidae), a Jumping Spider From Queensland

Bavia aericeps Simon is a large plurident jumping spider that frequents palms and other trees in tropical Queensland, building unusually strong and spacious nests on the undersides of leaves. The display repertoire of this species is large and complex, numerous distinct visual, vibratory, and tactile signals being used. Courtship is versatile, each male using one of three different mating tactics depending on the female's maturity and location. Type 1 courtship, involving specialized movements and postures of the legs, palps, and body, occurs if the female is an adult away from the nest; apparently this type of courtship is vision- dependent. If the male encounters an adult female inside her nest, he uses Type 2 courtship, which consists of movements that cause the silk to vibrate. If the female is a subadult inside her nest, the male initially uses Type 2 courtship, then builds a second chamber on the female's nest and cohabits until she moults and matures. Other displays occur during male-male and female-female interactions. Male-male interactions are particularly ferocious, the spiders often being upended and stunned. However, cannibalism seems to be of minor importance in this species.

The Biology of Mopsus mormon, a Jumping Spider (Araneae: Salticidae) from Queensland: Intraspecific Interactions

The display repertoire of Mopsus mormon is unusually large and complex for a salticid spider. Each individual has three different mating tactics, the one used depending on the female's maturity and location. With adult females outside nests males use type 1 courtship, which seems to be a form of visual communication and includes specialized movements and postures of the legs, palps, and body. With adult females inside nests, males use type 2 courtship, which seems to be a form of non-visual communication and consists of abdomen twitching and probing with the legs on the silk; males mate with receptive females inside the nests. With subadult females, males first use type 2 courtship, then spin an adjacent silken chamber and cohabit; after the female moults and matures, they mate inside the nest. Postmount courtship is an apparently non-visual phase that precedes copulation and occurs as a component of each tactic. Females and subadults also display; the displays used in interactions depend on the sex-age classes of the spiders involved.

Application of Jackson, Aspden Acute Myeloid Leukaemia model

The comparison of a series of small clinical trials into the treatment of Acute Myelogenous Leukaemia at St Bartholomew's Hospital, London, is described using a previously published mathematical model. The work demonstrates the value of a coherent presentation and analysis of available information in assisting clinicians in their decision-making.