248 research outputs found

    Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens

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    Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been dead. These estimates are based on species-specific details of the insects’ aging processes, and therefore require accurate species identification and developmental stage estimation. Many professionals who produce or use identified organisms as forensic evidence have little training in taxonomy or metrology, and appreciate the availability of formalized principles and standards for biological identification. Taxonomic identifications are usually most readily and economically made using categorical and qualitative morphological characters, but it may be necessary to use less convenient and potentially more ambiguous characters that are continuous and quantitative if two candidate species are closely related, or if identifying developmental stages within a species. Characters should be selected by criteria such as taxonomic specificity and metrological repeatability and relative error. We propose such a hierarchical framework, critique various measurements of immature insects, and suggest some standard approaches to determine the reliability of organismal identifications and measurements in estimating postmortem intervals. Relevant criteria for good characters include high repeatability (including low scope for ambiguity or parallax effects), pronounced discreteness, and small relative error in measurements. These same principles apply to individuation of unique objects in general

    New collection records for Theraphosidae (Araneae, Mygalomorphae) in Angola, with the description of a remarkable new species of Ceratogyrus

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    During 2015 and 2016 several baboon spider specimens (Araneae: Theraphosidae) were collected in central Angola during surveys undertaken for the Okavango Wilderness Project. These collections represent range and habitat extensions for Pterinochilus Pocock, 1897, Ceratogyrus Pocock, 1897 and Phoneyusa Karsch, 1884. The new species Ceratogyrus attonitifer sp. n. is described from female specimens and the distribution of genera mapped. Central and eastern Angola is severely under sampled for theraphosid spiders, with every species collected during the survey either being potentially new to science or representing a significant range extension for the genus.The National Geographic Okavango Wilderness Project, the KwaZulu-Natal Museum and the University of Pretoria.https://africaninvertebrates.pensoft.netam2020Zoology and Entomolog

    The final instar exuvium of Pycna semiclara Germar, 1834 (Hemiptera Cicadidae)

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    Exuviae of the cicada Pycna semiclara were found next to freshly eclosed adults. The exuvium of Pycna Semiclara is described and illustrated for the first time and a key is presented to distinguish the exuvium of this species from those of Platypleura stridula and Platypleura capensis, the only other species of cicadas from southern Africa for which exuviae have been described

    The final instar exuvium of Pycna semiclara Germar, 1834 (Hemiptera Cicadidae)

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    Exuviae of the cicada Pycna semiclara were found next to freshly eclosed adults. The exuvium of Pycna Semiclara is described and illustrated for the first time and a key is presented to distinguish the exuvium of this species from those of Platypleura stridula and Platypleura capensis, the only other species of cicadas from southern Africa for which exuviae have been described

    Determination of species and instars of the larvae of the Afrotropical species of Thanatophilus Leach, 1817 (Coleoptera, Silphidae)

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    Thanatophilus micans and T. mutilatus have significance for forensic entomology. Their larvae are therefore described and a key is provided for identifying the larvae of Afrotropical Silphidae based on morphological characters. It is shown that seven common species of Thanatophilus can be distinguished by a 360 bp mtDNA sequence from the cytochrome oxidase I gene

    Corrigenda: Daniel CA, Midgley JM, Villet MH (2017) Determination of species and instars of the larvae of the Afrotropical species of Thanatophilus Leach, 1817 (Coleoptera, Silphidae). African Invertebrates 58(2): 1-10. https://doi.org/10.3897/afrinvertebr.58.12966

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    After the publication of this article, it was brought to our attention that there was an error in the caption for Figure 2. The caption should read: Figure 2: Right mandible in dorsal view and mesothoracic spiracle of mature Afrotropical Thanatophilus larvae. The arrows indicate species-specific diagnostic characteristics: T. micans has two ventrolateral mandibular setae and two spiracular setae, while T. mutilatus has three ventrolateral mandibular setae and one spiracular seta

    Neurodevelopment and ages of onset in depressive disorders

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    How and why do clinical depressive disorders emerge in adolescence? In this Personal View, we present a neurodevelopmental theory to address causes for adolescent onsets of clinical depressive disorders. We argue that theories should account for three perplexing aspects of depressive disorders in adolescence: the episodic nature of depression; differences between sexes in rates of depression across development; and age-differentiated onsets. We consider how theories such as psychosocial acceleration, heterochronic brain development, dual-process models, glucocorticoid vulnerability hypothesis linked to early life stress, and epigenetic and genetic susceptibility might explain some aspects of adolescent depressive disorders. We argue that some synthesis between existing theories might be needed to establish a sufficient neurodevelopmental theoretical framework to explain onsets of depressive disorders in adolescence

    The first record of Omosita nearctica Kirejtshuk (Coleoptera, Nitidulidae) in South Africa, with the first description of its mature larva

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    Sap beetles of the genus Omosita Erichson are stored-product pests that are also associated with carrion, potentially making them biosecurity risks and forensic tools. The discovery of a specimen of the Nearctic species Omosita nearctica Kirejtshuk in South Africa prompted an investigation a decade later to determine if this species had established itself in the country, which was confirmed by the collection of further breeding specimens that also facilitated the first description of mature larvae of O. nearctica. A new key to adults of all Omosita species is presented

    Toward precision therapeutics: general and specific factors differentiate symptom change in depressed adolescents.

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    BACKGROUND: The longitudinal course of multiple symptom domains in adolescents treated for major depression is not known. Revealing the temporal course of general and specific psychopathology factors, including potential differences between psychotherapies, may aid therapeutic decision-making. METHODS: Participants were adolescents with major depressive disorder (aged 11-17; 75% female; N = 465) who were part of the IMPACT trial, a randomized controlled trial comparing cognitive behavioral therapy, short-term psychoanalytic psychotherapy, and brief psychosocial intervention. Self-reported symptoms at baseline and 6, 12, 36, 52, and 86 weeks postrandomization were analyzed with bifactor modeling. RESULTS: General psychopathology factor scores decreased across treatment and one-year follow-up. Specific melancholic features and depressive cognitions factors decreased from baseline to 6 weeks. Conduct problems decreased across treatment and follow-up. Anxiety increased by 6 weeks and then reverted to baseline levels. Obsessions-compulsions did not change. Changes in general and specific factors were not significantly different between the three psychotherapies during treatment. During follow-up, however, conduct problems decreased more in brief psychosocial intervention versus cognitive behavioral therapy (1.02, 95% Bayes credible interval 0.25, 1.96), but not versus short-term psychoanalytic psychotherapy. CONCLUSIONS: The clinical response signature in this trial is best revealed by rapid reductions in depression symptoms and general psychopathology. Protracted improvements in general psychopathology and conduct problems subsequently occur. Psychosocial treatments for adolescent depression have comparable effects on general and specific psychopathology, although a psychoeducational, goal-focused approach may be indicated for youth with comorbid conduct problems

    Aspergillus hancockii sp. Nov., a biosynthetically talented fungus endemic to southeastern Australian soils

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    Aspergillus hancockii sp. nov., classified in Aspergillus subgenus Circumdati section Flavi, was originally isolated from soil in peanut fields near Kumbia, in the South Burnett region of southeast Queensland, Australia, and has since been found occasionally from other substrates and locations in southeast Australia. It is phylogenetically and phenotypically related most closely to A. leporis States and M. Chr., but differs in conidial colour, other minor features and particularly in metabolite profile. When cultivated on rice as an optimal substrate, A. hancockii produced an extensive array of 69 secondary metabolites. Eleven of the 15 most abundant secondary metabolites, constituting 90% of the total area under the curve of the HPLC trace of the crude extract, were novel. The genome of A. hancockii, approximately 40 Mbp, was sequenced and mined for genes encoding carbohydrate degrading enzymes identified the presence of more than 370 genes in 114 gene clusters, demonstrating that A. hancockii has the capacity to degrade cellulose, hemicellulose, lignin, pectin, starch, chitin, cutin and fructan as nutrient sources. Like most Aspergillus species, A. hancockii exhibited a diverse secondary metabolite gene profile, encoding 26 polyketide synthase, 16 nonribosomal peptide synthase and 15 nonribosomal peptide synthase-like enzymes
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