82 research outputs found
First observation of Dorylus ant feeding in Budongo chimpanzees supports absence of stick-tool culture
The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no 283871.The use of stick- or probe-tools is a chimpanzee universal, recorded in all long-term study populations across Africa, except one: Budongo, Uganda. Here, after 25-years of observation, stick-tool use remains absent under both natural circumstances and strong experimental scaffolding. Instead, the chimpanzees employ a rich repertoire of leaf-tools for a variety of dietary and hygiene tasks. One use of stick-tools in other communities is in feeding on the aggressive Dorylus ‘army-ant’ species, consumed by chimpanzees at all long-term study sites outside of mid-Western Uganda. Here we report the first observation of army-ant feeding in Budongo, in which individuals from the Waibira chimpanzee community employed detached leaves to feed on a ground swarm. We describe the behaviour and discuss whether or not it can be considered tool-use, together with its implication for the absence of stick-tool ‘culture’ in Budongo chimpanzees.Publisher PDFPeer reviewe
Molecule-by-Molecule Writing Using a Focused Electron Beam
The resolution of lithography techniques needs to be extended beyond their current limits to continue the trend of miniaturization and enable new applications. But what is the ultimate spatial resolution? It is known that single atoms can be imaged with a highly focused electron beam. Can single atoms also be written with an electron beam? We verify this with focused electron-beam-induced deposition (FEBID), a direct-write technique that has the current record for the smallest feature written by (electron) optical lithography. We show that the deposition of an organometallic precursor on graphene can be followed molecule-by-molecule with FEBID. The results show that mechanisms that are inherent to the process inhibit a further increase in control over the process. Hence, our results present the resolution limit of (electron) optical lithography techniques. The writing of isolated, subnanometer features with nanometer precision can be used, for instance, for the local modification of graphene and for catalysis.</p
Geographic clustering of testicular cancer incidence in the northern part of The Netherlands
Geographic variations in testicular cancer incidence may be caused by differences in environmental factors, genetic factors, or both. In the present study, geographic patterns of age-adjusted testicular cancer incidence rates (IRs) in 12 provinces in The Netherlands in the period 1989–1995 were analysed. In addition, the age-adjusted IR of testicular cancer by degree of urbanization was evaluated. Cancer incidence data were obtained from the Netherlands Cancer Registry. The overall annual age-adjusted IR of testicular cancer in The Netherlands in the period 1989–1995 was 4.4 per 100 000 men. The province Groningen in the north of the country showed the highest annual IR with 5.8 per 100 000 men, which was higher (P < 0.05) than the overall IR in The Netherlands (incidence rate ratio (IRR) 1.3, 95% confidence interval (CI) 1.1–1.6). The highest IR in Groningen was seen for both seminomas and non-seminomas. In addition, Groningen showed the highest age-specific IRs in all relevant younger age groups (15–29, 30–44 and 45–59 years), illustrating the consistency of data. The province Friesland, also situated in the northern part of the country, showed the second highest IR of testicular cancer with 5.3 cases per 100 000 men per year (IRR 1.2, 95% Cl 1.0–1.5, not significant). This mainly resulted from the high IR of seminoma in Friesland. Analysis of age-adjusted IRs of testicular cancer by degree of urbanization in The Netherlands showed no urban–rural differences at analysis of all histological types combined, or at separate analyses of seminomas and non-seminomas. Geographic clustering of testicular cancer seems to be present in the rural north of The Netherlands with some stable founder populations, which are likely to share a relatively high frequency of genes from common ancestors including genes possibly related to testicular cancer. Although this finding does not exclude the involvement of shared environmental factors in the aetiology of testicular cancer, it may also lend support to a genetic susceptibility to testicular cancer development. Testicular cancer cases in stable founder populations seem particularly suitable for searching for testicular cancer susceptibility genes because such genes are likely to be more frequent among affected men in such populations. © 1999 Cancer Research Campaig
Phylogenetic and functional marker genes to study ammonia-oxidizing microorganisms (AOM) in the environment
The oxidation of ammonia plays a significant role in the transformation of fixed nitrogen in the global nitrogen cycle. Autotrophic ammonia oxidation is known in three groups of microorganisms. Aerobic ammonia-oxidizing bacteria and archaea convert ammonia into nitrite during nitrification. Anaerobic ammonia-oxidizing bacteria (anammox) oxidize ammonia using nitrite as electron acceptor and producing atmospheric dinitrogen. The isolation and cultivation of all three groups in the laboratory are quite problematic due to their slow growth rates, poor growth yields, unpredictable lag phases, and sensitivity to certain organic compounds. Culture-independent approaches have contributed importantly to our understanding of the diversity and distribution of these microorganisms in the environment. In this review, we present an overview of approaches that have been used for the molecular study of ammonia oxidizers and discuss their application in different environments
Subcortical volumes across the lifespan: Data from 18,605 healthy individuals aged 3-90 years
Age has a major effect on brain volume. However, the normative studies available are constrained by small sample sizes, restricted age coverage and significant methodological variability. These limitations introduce inconsistencies and may obscure or distort the lifespan trajectories of brain morphometry. In response, we capitalized on the resources of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Consortium to examine age-related trajectories inferred from cross-sectional measures of the ventricles, the basal ganglia (caudate, putamen, pallidum, and nucleus accumbens), the thalamus, hippocampus and amygdala using magnetic resonance imaging data obtained from 18,605 individuals aged 3-90 years. All subcortical structure volumes were at their maximum value early in life. The volume of the basal ganglia showed a monotonic negative association with age thereafter; there was no significant association between age and the volumes of the thalamus, amygdala and the hippocampus (with some degree of decline in thalamus) until the sixth decade of life after which they also showed a steep negative association with age. The lateral ventricles showed continuous enlargement throughout the lifespan. Age was positively associated with inter-individual variability in the hippocampus and amygdala and the lateral ventricles. These results were robust to potential confounders and could be used to examine the functional significance of deviations from typical age-related morphometric patterns
A systematic review of non-invasive modalities used to identify women with anal incontinence symptoms after childbirth
© 2018, The International Urogynecological Association. Introduction and hypothesis: Anal incontinence following childbirth is prevalent and has a significant impact upon quality of life (QoL). Currently, there is no standard assessment for women after childbirth to identify these symptoms. This systematic review aimed to identify non-invasive modalities used to identify women with anal incontinence following childbirth and assess response and reporting rates of anal incontinence for these modalities. Methods: Ovid Medline, Allied and Complementary Medicine Database (AMED), Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane Collaboration, EMBASE and Web of Science databases were searched for studies using non-invasive modalities published from January 1966 to May 2018 to identify women with anal incontinence following childbirth. Study data including type of modality, response rates and reported prevalence of anal incontinence were extracted and critically appraised. Results: One hundred and nine studies were included from 1602 screened articles. Three types of non-invasive modalities were identified: validated questionnaires/symptom scales (n = 36 studies using 15 different instruments), non-validated questionnaires (n = 50 studies) and patient interviews (n = 23 studies). Mean response rates were 92% up to 6 weeks after childbirth. Non-personalised assessment modalities (validated and non-validated questionnaires) were associated with reporting of higher rates of anal incontinence compared with patient interview at all periods of follow-up after childbirth, which was statistically significant between 6 weeks and 1 year after childbirth (p < 0.05). Conclusions: This systematic review confirms that questionnaires can be used effectively after childbirth to identify women with anal incontinence. Given the methodological limitations associated with non-validated questionnaires, assessing all women following childbirth for pelvic-floor symptomatology, including anal incontinence, using validated questionnaires should be considered
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