102 research outputs found
Topology from enrichment: the curious case of partial metrics
For any small quantaloid \Q, there is a new quantaloid \D(\Q) of
diagonals in \Q. If \Q is divisible then so is \D(\Q) (and vice versa),
and then it is particularly interesting to compare categories enriched in \Q
with categories enriched in \D(\Q). Taking Lawvere's quantale of extended
positive real numbers as base quantale, \Q-categories are generalised metric
spaces, and \D(\Q)-categories are generalised partial metric spaces, i.e.\
metric spaces in which self-distance need not be zero and with a suitably
modified triangular inequality. We show how every small quantaloid-enriched
category has a canonical closure operator on its set of objects: this makes for
a functor from quantaloid-enriched categories to closure spaces. Under mild
necessary-and-sufficient conditions on the base quantaloid, this functor lands
in the category of topological spaces; and an involutive quantaloid is
Cauchy-bilateral (a property discovered earlier in the context of distributive
laws) if and only if the closure on any enriched category is identical to the
closure on its symmetrisation. As this now applies to metric spaces and partial
metric spaces alike, we demonstrate how these general categorical constructions
produce the "correct" definitions of convergence and Cauchyness of sequences in
generalised partial metric spaces. Finally we describe the Cauchy-completion,
the Hausdorff contruction and exponentiability of a partial metric space, again
by application of general quantaloid-enriched category theory.Comment: Apart from some minor corrections, this second version contains a
revised section on Cauchy sequences in a partial metric spac
Exponentiable functors between quantaloid-enriched categories
Exponentiable functors between quantaloid-enriched categories are
characterized in elementary terms. The proof goes as follows: the elementary
conditions on a given functor translate into existence statements for certain
adjoints that obey some lax commutativity; this, in turn, is precisely what is
needed to prove the existence of partial products with that functor; so that
the functor's exponentiability follows from the works of Niefield [1980] and
Dyckhoff and Tholen [1987].Comment: 10 pages; correction of flaw in proo
New combinations in Lactifluus, 2 : L. subg. Gerardii
In this second of a series of three papers, new combinations in the genus Lactifluus are proposed. This paper treats Lactarius subg. Gerardii (proposed here as new combination in Lactifluus). In this subgenus 17 combinations at species level are proposed
A multi-gene phylogeny of Lactifluus (Basidiomycota, Russulales) translated into a new infrageneric classification of the genus
Infrageneric relations of the genetically diverse milkcap genus Lactifluus (Russulales, Basidiomycota) are poorly known. Currently used classification systems still largely reflect the traditional, mainly morphological, characters used for infrageneric delimitations of milkcaps. Increased sampling, combined with small-scale molecular studies, show that this genus is underexplored and in need of revision. For this study, we assembled an extensive dataset of the genus Lactifluus, comprising 80 % of all known species and 30 % of the type collections. To unravel the infrageneric relationships within this genus, we combined a multi-gene molecular phylogeny, based on nuclear ITS, LSU, RPB2 and RPB1, with a morphological study, focussing on five important characteristics (fruit body type, presence of a secondary velum, colour reaction of the latex/context, pileipellis type and presence of true cystidia). Lactifluus comprises four supported subgenera, each containing several supported clades. With extensive sampling, ten new clades and at least 17 new species were discovered, which highlight the high diversity in this genus. The traditional infrageneric classification is only partly maintained and nomenclatural changes are proposed. Our morphological study shows that the five featured characteristics are important at different evolutionary levels, but further characteristics need to be studied to find morphological support for each clade. This study paves the way for a more detailed investigation of biogeographical history and character evolution within Lactifluus
\u3ci\u3eHypsugo stubbei\u3c/i\u3e sp. nov., A Novel Cryptic Bat Species of the Genus \u3ci\u3eHypsugo\u3c/i\u3e (Vespertilionidae, Chiroptera, Mammalia) from Mongolia
The occurrence of two members of the genus Hypsugo, namely H. alaschanicus and H. savii caucasicus, have been reported for Mongolia in the literature. Due to various taxonomic reassignments within and between genera, the number of records for the genus Hypsugo in Mongolia is quite scarce and sometimes not resolved at species or subspecies level. Despite recognition of the two above-mentioned species, recent reports based on genetic analyses describe only new and further records of H. alaschanicus. Thus, it exists a large uncertainty regarding the occurrence and distribution of H. savii caucasicus in Mongolia. Here, our efforts in gaining a deeper understanding towards the occurrence and distribution of Hypsugo species in Mongolia are described.
A combination of genetic and morphological analyses of collected material from Hypsugo specimens revealed the existence of a genetically largely distant Hypsugo clade. Therefore, a new and cryptic Hypsugo species is proposed which is named after Prof. Dr. Michael Stubbe for his continuous, long-standing and significant contributions into the biological exploration of Mongolia. Hypsugo stubbei sp. nov. differs by at least 8.4 % and 9 % to the closest Western Palearctic distributed H. cf. darwinii and H. savii as well as at least 11.3 % to the Easter Palearctic (including Mongolia) distributed H. alaschanicus based on the first 798 nucleotides of the gene encoding the mitochondrial ND1 (subunit one of NADH dehydrogenase). Neither a close proximity species based on the gene encoding the mitochondrial COI (cytochrome oxidase subunit one) could be found in publicly accessible nucleotide databases. While the cryptic H. stubbei sp. nov. reveals no obvious cranial and morphological differences, few external characteristics are dissimilar to both H. alaschanicus and H. savii (caucasicus). Currently, Hypsugo stubbei sp. nov. was found at four different locations in Mongolia. Among the 11 specimens captured, six facilitated a genetic assignment. Based on the current scarce data records, the species seems to occur mainly in the far west of Mongolia inhabiting semi-deserts and steppes up to high mountain areas. An overlapping distribution with H. alaschanicus cannot be excluded based on the limited data currently available
Selten in der Mongolei nachgewiesene Fledermausarten
In der Mongolei sind gegenwärtig 20 verschiedene Fledermausarten aus sieben Gattungen nachgewiesen worden. Hierbei handelt es sich um sieben Arten Myotis, vier Arten Plecotus, drei Arten Eptesicus, zwei Arten Vespertilio, zwei Arten Hypsugo und je eine Art der Gattungen Nyctalus und Murina. Von den bisher bekannten Species konnten 11 nur selten und zwei von ihnen nur einmal gefunden worden. Bis auf die Arten der Gattung Plecotus und Hypsugo, die in getrennten Publikationen in diesem Heft behandelt werden (DOLCH et al. 2021a, 2021b), sind nachfolgend diese seltenen Funde zusammengestellt. Die Grundlage für die Häufigkeitseinschätzung bilden über 2000 Fledermausfänge an über 100 Fangplätzen der Feldexpeditionen „Chiroptera Mongolia“ (seit 1999) und der Mongolisch-Deutschen Biologischen Expeditionen, die seit 1962 unter der Leitung von Michael Stubbe in unterschiedlicher Zusammensetzung durchgeführt wurden
The taxonomy of the Trichophyton rubrum complex: a phylogenomic approach
The medically relevant Trichophyton rubrum species complex has a variety of phenotypic presentations but shows relatively little genetic differences. Conventional barcodes, such as the internal transcribed spacer (ITS) region or the beta-tubulin gene, are not able to completely resolve the relationships between these closely related taxa. T. rubrum, T. soudanense and T. violaceum are currently accepted as separate species. However, the status of certain variants, including the T. rubrum morphotypes megninii and kuryangei and the T. violaceum morphotype yaoundei, remains to be deciphered. We conducted the first phylogenomic analysis of the T. rubrum species complex by studying 3105 core genes of 18 new strains from the BCCM/IHEM culture collection and nine publicly available genomes. Our analyses revealed a highly resolved phylogenomic tree with six separate clades. Trichophyton rubrum, T. violaceum and T. soudanense were confirmed in their status of species. The morphotypes T. megninii, T. kuryangei and T. yaoundei all grouped in their own respective clade with high support, suggesting that these morphotypes should be reinstituted to the species-level. Robinson-Foulds distance analyses showed that a combination of two markers (a ubiquitin-protein transferase and a MYB DNA-binding domain-containing protein) can mirror the phylogeny obtained using genomic data, and thus represent potential new markers to accurately distinguish the species belonging to the T. rubrum complex
Prognostic Relevance of Cardiopulmonary Exercise Testing for Patients with Chronic Thromboembolic Pulmonary Hypertension
Following acute pulmonary embolism (PE), a relevant number of patients
experience decreased exercise capacity which can be associated with disturbed pulmonary perfusion.
Cardiopulmonary exercise testing (CPET) shows several patterns typical for disturbed pulmonary
perfusion. Research question: We aimed to examine whether CPET can also provide prognostic
information in chronic thromboembolic pulmonary hypertension (CTEPH). Study Design and Methods:
We performed a multicenter retrospective chart review in Germany between 2002 and 2020.
Patients with CTEPH were included if they had 6 months of follow-up and complete CPET and
hemodynamic data. Symptom-limited CPET was performed using a cycle ergometer (ramp or Jones
protocol). The association of anthropometric data, comorbidities, symptoms, lung function, and
echocardiographic, hemodynamic, and CPET parameters with survival was examined. Mortality
prediction models were calculated by Cox regression with backward selection. Results: 345 patients
(1532 person-years) were included; 138 underwent surgical treatment (pulmonary endarterectomy or
balloon pulmonary angioplasty) and 207 received only non-surgical treatment. During follow-up
(median 3.5 years), 78 patients died. The death rate per 1000 person-years was 24.9 and 74.2 in the
surgical and non-surgical groups, respectively (p < 0.001). In age- and sex-adjusted Cox regression
analyses, CPET parameters including peak oxygen uptake (VO2peak, reflecting cardiopulmonary
exercise capacity) were prognostic in the non-surgical group but not in the surgical group. In mortality
prediction models, age, sex, VO2peak (% predicted), and carbon monoxide transfer coefficient (%
predicted) showed significant prognostic relevance in both the overall cohort and the non-surgical
group. In the non-surgical group, Kaplan–Meier analysis showed that patients with VO2peak below
53.4% predicted (threshold identified by receiver operating characteristic analysis) had increased
mortality (p = 0.007). Interpretation: The additional measurement of cardiopulmonary exercise
capacity by CPET allows a more precise prognostic evaluation in patients with CTEPH. CPET might therefore be helpful for risk-adapted treatment of CTEPH
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