135 research outputs found
Resolving the Evolutionary History of Campanula (Campanulaceae) in Western North America
Recent phylogenetic works have begun to address long-standing questions regarding the systematics of Campanula (Campanulaceae). Yet, aspects of the evolutionary history, particularly in northwestern North America, remain unresolved. Thus, our primary goal in this study was to infer the phylogenetic positions of northwestern Campanula species within the greater Campanuloideae tree. We combined new sequence data from 5 markers (atpB, rbcL, matK, and trnL-F regions of the chloroplast and the nuclear ITS) representing 12 species of Campanula with previously published datasets for worldwide campanuloids, allowing us to include approximately 75% of North American Campanuleae in a phylogenetic analysis of the Campanuloideae. Because all but one of North American Campanula species are nested within a single campanuloid subclade (the Rapunculus clade), we conducted a separate set of analyses focused specifically on this group. Our findings show that i) the campanuloids have colonized North America at least 6 times, 4 of which led to radiations, ii) all but one North American campanuloid are nested within the Rapunculus clade, iii) in northwestern North America, a C. piperi â C. lasiocarpa ancestor gave rise to a monophyletic Cordilleran clade that is sister to a clade containing C. rotundifolia, iv) within the Cordilleran clade, C. parryi var. parryi and C. parryi var. idahoensis exhibit a deep, species-level genetic divergence, and v) C. rotundifolia is genetically diverse across its range and polyphyletic. Potential causes of diversification and endemism in northwestern North America are discussed
The beginning of time? Evidence for catastrophic drought in Baringo in the early nineteenth century
New developments in the collection of palaeo-data over the past two decades have transformed our understanding of climate and environmental history in eastern Africa. This article utilises instrumental and proxy evidence of historical lake-level fluctuations from Baringo and Bogoria, along with other Rift Valley lakes, to document the timing and magnitude of hydroclimate variability at decadal to century time scales since 1750. These data allow us to construct a record of past climate variation not only for the Baringo basin proper, but also across a sizable portion of central and northern Kenya. This record is then set alongside historical evidence, from oral histories gathered amongst the peoples of northern Kenya and the Rift Valley and from contemporary observations recorded by travellers through the region, to offer a reinterpretation of human activity and its relationship to environmental history in the nineteenth century. The results reveal strong evidence of a catastrophic drought in the early nineteenth century, the effects of which radically alters our historical understanding of the character of settlement, mobility and identity within the BaringoâBogoria basin
Body composition and body fat distribution are related to cardiac autonomic control in non-alcoholic fatty liver disease patients
BACKGROUND/OBJECTIVES: Heart rate recovery (HRR), a cardiac autonomic control marker, was shown to be related to body composition (BC), yet this was not tested in non-alcoholic fatty liver disease (NAFLD) patients. The aim of this study was to determine if, and to what extent, markers of BC and body fat (BF) distribution are related to cardiac autonomic control in NAFLD patients. SUBJECTS/METHODS: BC was assessed with dual-energy X-ray absorptiometry in 28 NAFLD patients (19 men, 51±13 years, and 9 women, 47±13 years). BF depots ratios were calculated to assess BF distribution. Subjectsâ HRR was recorded 1 (HRR1) and 2 min (HRR2) immediately after a maximum graded exercise test.
RESULTS: BC and BF distribution were related to HRR; particularly weight, trunk BF and trunk BF-to-appendicular BF ratio showed a negative relation with HRR1 (r 1â4 0.613, r 1â4 0.597 and r 1â4 0.547, respectively, Po0.01) and HRR2 (r 1â4 0.484, r 1â4 0.446, Po0.05, and r 1â4 0.590, Po0.01, respectively). Age seems to be related to both HRR1 and HRR2 except when controlled for BF distribution. The preferred model in multiple regression should include trunk BF-to-appendicular BF ratio and BF to predict HRR1 (r2 1â4 0.549; Po0.05), and trunk BF-to-appendicular BF ratio alone to predict HRR2 (r2 1â4 0.430; Po0.001).
CONCLUSIONS: BC and BF distribution were related to HRR in NAFLD patients. Trunk BF-to-appendicular BF ratio was the best independent predictor of HRR and therefore may be best related to cardiovascular increased risk, and possibly act as a mediator in age-related cardiac autonomic control variation.info:eu-repo/semantics/publishedVersio
Phylogenetic relationships and phylogeography of relevant lineages within the complex Campanulaceae family in Macaronesia
Original ResearchMacaronesia has long been recognized as a natural model for studying evolutionary
processes in plant diversification. Several studies have attempted to focus on single
lineages, and few have covered the diversification of a family across all the archipelagos.
We used a comprehensive sample to clarify the phylogenetic relationships and
the biogeographic history of the Macaronesian Campanulaceae. Hypotheses related
to the colonization of these archipelagos will be used to examine the diversification
patterns of different lineages. We sequenced the ITS region and six cpDNA markers
(atpB, matK, petD, rbcL, trnL-F, and psbA-trnH) from 10 Campanulaceae species, including
seven endemic species in Macaronesia. The phylogeny of these taxa was reconstructed
using maximum parsimony, maximum likelihood, and Bayesian inference. To
study the relationships within each lineage, haplotype networks were calculated using
NeighborNet and TCS algorithms. Moreover, data were combined with fossil information
to construct time-calibrated
trees for the Macaronesian Campanulaceae species.
The phylogenetic analyses are largely congruent with current taxon circumscriptions,
and all the endemic genera formed monophyletic clades, namely Azorina in Azores;
Musschia in Madeira; and Campanula in Cape Verde. The Azorina clade and the Cape
Verde endemic Campanula may share a common ancestor in North Africa, and the divergence
was dated ca. 12.3 million years ago (Mya). The divergence of the Musschia
clade began in the Pliocene ca. 3.4 Mya. Moreover, several examples of intraspecific
variation were revealed among the native species with a clear geographic structured
patterns, suggesting that cryptic diversity might exist within the native Macaronesian
Campanulaceae when compared to the close mainland taxa (e.g., Campanula erinus,
Trachelium caeruleum), but additional studies are needed to support the molecular
data. This study highlights the power of combining data (e.g., phylogeny and divergence
times, with species distribution data) for testing diversification hypotheses
within the unique Macaronesian flora, providing useful information for future conservation
efforts.info:eu-repo/semantics/publishedVersio
Factors associated with parasympathetic activation following exercise in patients with rheumatoid arthritis: a cross-sectional study
Background Patients with rheumatoid arthritis (RA) have an increased risk for cardiovascular disease (CVD) with poor parasympathetic function being implicated as an underlying factor. Factors related to parasympathetic function, commonly assessed by heart rate recovery (HRR) following maximal exercise, are currently not known in RA. We aimed to explore the association between HRR with CVD risk factors, inflammatory markers, and wellbeing in patients with RA. Methods Ninety-six RA patients (54.4â±â12.6 years, 68 % women) completed a treadmill exercise test, during which heart rate (HR) was monitored. HRR1 and HRR2 were defined as the absolute change from HR peak to HRR 1 min post HR peak and 2 min post HR peak, respectively. Cardiorespiratory fitness, CVD risk factors, and serological markers of inflammation were measured in all patients. The Framingham Risk Score (FRS) was used as an assessment of global risk for CVD events, and wellbeing was assessed by questionnaires. Results Mean HRR1 and HRR2 were 29.1â±â13.2 bpm and 46.4â±â15.3 bpm, respectively. CVD risk factors as well as most inflammatory markers and measures of wellbeing were inversely correlated with HRR1 and HRR2. Multivariate regression analyses revealed that 27.9 % of the variance in HRR1 and 37.9 % of the variance in HRR2 was explained collectively by CVD risk factors, measures of inflammation, and wellbeing (pâ=â0.009, pâ=â0.001 respectively), however no individual measure was independently associated with HRR1 or HRR2. Conclusion Parasympathetic activation was associated with overall CVD risk, arthritis-related burden and wellbeing in patients with RA
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