Dyslipidaemia and hypertension care have not been reported in large samples of community-based participants with known diabetes (KD) nor compared with individuals at high risk for diabetes.
To ...describe the management and associations of dyslipidaemia and hypertension in adults with KD, newly diagnosed diabetes (NDD) and normoglycaemia.
This urban population-based cross-sectional study comprised participants with KD, NDD and normoglycaemia. Participants at high risk for diabetes but without KD underwent oral glucose tolerance tests; those who were subsequently classified as NDD or normoglycaemic were included in this study. Data collection comprised administered questionnaires, clinical measurements and biochemical analyses. Multivariable logistic regressions determined the associations with hypertension and dyslipidaemia management in separate models.
Among 618 participants (82% women), aged median 58 years, there were 339 participants with KD, 70 with NDD and 209 with normoglycaemia. Prevalence of hypertension (BP ≥140/90 mmHg or on treatment) and dyslipidaemia (raised low-density lipoprotein cholesterol >3 mmol/L or on treatment) was highest in KD (89% and 83%) compared with NDD (64% and 74%) and normoglycaemia (66% for both) (p<0.001). Detected or known hypertension was highest in KD (97.4%), followed by NDD (88.9%) and normoglycaemia (80.3%). Among participants with known or detected hypertension, those with KD were most likely to be treated (90.2%) compared with NDD (77.5%) and normoglycaemia (74.5.%). Hypertension control among participants on treatment was highest in KD (69.5%) compared with NDD (51.6%) and normoglycaemia (61.0%). Participants with KD had significantly higher rates of previously detected dyslipidaemia (85.1%) compared with NDD (36.5%) and normoglycaemia (35.5%). KD participants were also more likely to be treated for their previously detected dyslipidaemia (85.4%) and to be controlled when on treatment (56.3%) compared with their counterparts (NDD: 63.2% and 33.3%, normoglycaemia: 61.2% and 43.3%, respectively). Diabetes control was poor; only 20% of those with KD had HbA1c <7%. In the regression models, compared with normoglycaemia, KD was associated with hypertension detection (odds ratio (OR) 6.91, 95% confidence interval (CI) 2.25 - 21.22) and control (OR 2.05, 95% CI 1.04 - 4.02). KD compared with normoglycaemia was associated with dyslipidaemia detection (OR 10.29, 95% CI 5.21 - 20.32) and treatment (OR 3.94, 95% CI 1.68 - 9.27). Sociodemographic and cardiovascular disease risk factors were generally not associated with hypertension or dyslipidaemia management.
Albeit that diabetes control was poor and required better management, dyslipidaemia and hypertension prevalence were higher and better managed in KD than NDD and normoglycaemia. Different approaches are required to improve glucose control in KD, better identify NDD and monitor and prevent diabetes in high-risk individuals. Also important would be to improve care of hypertension and dyslipidaemia in those without KD.
The 1.28 GHz MeerKAT Galactic Center Mosaic Heywood, I.; Rammala, I.; Camilo, F. ...
Astrophysical journal/The Astrophysical journal,
02/2022, Letnik:
925, Številka:
2
Journal Article
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Abstract
The inner ∼200 pc region of the Galaxy contains a 4 million M
⊙
supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic-ray energy densities ...that are roughly two orders of magnitude higher than the corresponding levels in the Galactic disk. At a distance of only 8.2 kpc, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the SMBH and star-formation-driven feedback processes that are known to influence the evolution of galaxies as a whole. We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope. Radio imaging offers a view that is unaffected by the large quantities of dust that obscure the region at other wavelengths, and a scene of striking complexity is revealed. We produce total-intensity and spectral-index mosaics of the region from 20 pointings (144 hr on-target in total), covering 6.5 square degrees with an angular resolution of 4″ at a central frequency of 1.28 GHz. Many new features are revealed for the first time due to a combination of MeerKAT’s high sensitivity, exceptional
u
,
v
-plane coverage, and geographical vantage point. We highlight some initial survey results, including new supernova remnant candidates, many new nonthermal filament complexes, and enhanced views of the Radio Arc bubble, Sagittarius A, and Sagittarius B regions. This project is a South African Radio Astronomy Observatory public legacy survey, and the image products are made available with this article.
The 1.28 GHz MeerKAT DEEP2 Image Cotton, W. D.; Matthews, A. M.; Abbott, T. D. ...
Astrophysical journal/The Astrophysical journal,
01/2020, Letnik:
888, Številka:
2
Journal Article
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We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one primary-beam area with θ = 7 6 FWHM resolution and rms noise. Its J2000 center position = 04h 13m 26 4, δ = −80° 00′ 00″ was ...selected to minimize artifacts caused by bright sources. We introduce the new 64-element MeerKAT array and describe commissioning observations to measure the primary-beam attenuation pattern, estimate telescope pointing errors, and pinpoint (u, v) coordinate errors caused by offsets in frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the DEEP2 confusion P(D) distribution from 0.25 to 10 Jy with counts of individual DEEP2 sources between 10 Jy and 2.5 mJy. Most sources fainter than S ∼ 100 Jy are distant star-forming galaxies (SFGs) obeying the far-IR/radio correlation, and sources stronger than 0.25 Jy account for ∼93% of the radio background produced by SFGs. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent with the Madau & Dickinson model for the evolution of SFGs based on UV and infrared data underpredicts our 1.4 GHz source count in the range .
Long-term ('superorbital') periods or modulations have been detected in a wide variety of both low- and high-mass X-ray binaries at X-ray and optical wavelengths. A variety of mechanisms have been ...proposed to account for the variability properties, such as precessing and/or warped accretion discs, amongst others. The All Sky Monitor onboard the Rossi X-ray Timing Explorer provides the most extensive (∼15 years) and sensitive X-ray archive for studying such behaviour. It is also clear that such variations can be intermittent and/or a function of X-ray spectral state. Consequently, we use a time-dependent dynamic power spectrum method to examine how these modulations vary with time in 25 X-ray binaries for which superorbital periodicities have been previously reported. Our aim is to characterize these periodicities in a completely systematic way. Some (such as Her X-1 and LMC X-4) are remarkably stable, but others show a range of properties, from even longer variability time-scales to quite chaotic behaviour.
The construction of the seven-dish Karoo Array Telescope (KAT-7) array in the Karoo region of the Northern Cape in South Africa was intended primarily as an engineering prototype for technologies and ...techniques applicable to the MeerKAT telescope. This paper looks at the main engineering and scientific highlights from this effort, and discusses their applicability to both MeerKAT and other next-generation radio telescopes. In particular, we found that the composite dish surface works well, but it becomes complicated to fabricate for a dish lacking circular symmetry; the Stirling cycle cryogenic system with ion pump to achieve vacuum works but demands much higher maintenance than an equivalent Gifford–McMahon cycle system; the ROACH (Reconfigurable Open Architecture Computing Hardware)-based correlator with SPEAD (Streaming Protocol for Exchanging Astronomical Data) protocol data transfer works very well and KATCP (Karoo Array Telescope Control Protocol) control protocol has proven very flexible and convenient. KAT-7 has also been used for scientific observations where it has a niche in mapping low surface-brightness continuum sources, some extended H i
haloes and OH masers in star-forming regions. It can also be used to monitor continuum source variability, observe pulsars, and make Very Long Baseline Interferometry observations.
ABSTRACT
We report the discovery of the first transient with MeerKAT, MKT J170456.2–482100, discovered in ThunderKAT images of the low-mass X-ray binary GX339–4. MKT J170456.2–482100 is variable in ...the radio, reaching a maximum flux density of $0.71\pm 0.11\, \mathrm{mJy}$ on 2019 October 12, and is undetected in 15 out of 48 ThunderKAT epochs. MKT J170456.2–482100 is coincident with the chromospherically active K-type sub-giant TYC 8332-2529-1, and $\sim 18\, \mathrm{yr}$ of archival optical photometry of the star shows that it varies with a period of $21.25\pm 0.04\, \mathrm{d}$. The shape and phase of the optical light curve changes over time, and we detect both X-ray and UV emission at the position of MKT J170456.2–482100, which may indicate that TYC 8332-2529-1 has large star spots. Spectroscopic analysis shows that TYC 8332-2529-1 is in a binary, and has a line-of-sight radial velocity amplitude of $43\, \mathrm{km\, s^{-1}}$. We also observe a spectral feature in antiphase with the K-type sub-giant, with a line-of-sight radial velocity amplitude of $\sim 12\pm 10\, \mathrm{km\, s^{-1}}$, whose origins cannot currently be explained. Further observations and investigation are required to determine the nature of the MKT J170456.2–482100 system.
The cheetah (Acinonyx jubatus) has been described as a species with low levels of genetic variation. This has been suggested to be the consequence of a demographic bottleneck 10 000–12 000 years ago ...(ya) and also led to the assumption that only small genetic differences exist between the described subspecies. However, analysing mitochondrial DNA and microsatellites in cheetah samples from most of the historic range of the species we found relatively deep phylogeographic breaks between some of the investigated populations, and most of the methods assessed divergence time estimates predating the postulated bottleneck. Mitochondrial DNA monophyly and overall levels of genetic differentiation support the distinctiveness of Northern‐East African cheetahs (Acinonyx jubatus soemmeringii). Moreover, combining archaeozoological and contemporary samples, we show that Asiatic cheetahs (Acinonyx jubatus venaticus) are unambiguously separated from African subspecies. Divergence time estimates from mitochondrial and nuclear data place the split between Asiatic and Southern African cheetahs (Acinonyx jubatus jubatus) at 32 000–67 000 ya using an average mammalian microsatellite mutation rate and at 4700–44 000 ya employing human microsatellite mutation rates. Cheetahs are vulnerable to extinction globally and critically endangered in their Asiatic range, where the last 70–110 individuals survive only in Iran. We demonstrate that these extant Iranian cheetahs are an autochthonous monophyletic population and the last representatives of the Asiatic subspecies A. j. venaticus. We advocate that conservation strategies should consider the uncovered independent evolutionary histories of Asiatic and African cheetahs, as well as among some African subspecies. This would facilitate the dual conservation priorities of maintaining locally adapted ecotypes and genetic diversity.
In South Africa, cheetahs (Acinonyx jubatus) occur as a relictual, unmanaged population of ‘free‐roamers’, a managed metapopulation across fenced reserves, and in various captive facilities. To ...ensure that the Cheetah Metapopulation Project (CMP) is not at risk of losing overall genetic variation to drift or inbreeding, we propose various interventions, including exchanges between free‐roamers and the metapopulation or supplementation with unrelated individuals from captivity. Simulated trajectories of genetic diversity under such intervention strategies over time could directly inform conservation action and policy towards securing the long‐term genetic integrity of the CMP. Single Nucleotide Polymorphisms (SNPs) were genotyped for 172 adult cheetahs across the free‐roamer population, the metapopulation, and three major captive facilities. Management intervention trajectory models were tested including, (1) no intervention, (2) genetic exchange between free‐roamers and the metapopulation, (3) translocation from a single captive facility and (4) translocation from several captive facilities into the metapopulation. Discriminant Analysis of Principal Components (DAPC) showed that two captive populations are highly differentiated from the metapopulation and each other, whilst the third captive and free‐roamer populations are genetically more similar to the metapopulation. Simulated genetic variation over 25 generations indicated that models 1 and 2 show significant losses of heterozygosity due to genetic drift and present a proportional increase in the frequencies of 1st‐ and 2nd‐degree relatives, whilst this variation and pairwise relatedness remain relatively constant under models 3 and 4. We emphasise the potential importance of captive facilities as reservoirs of genetic diversity in metapopulation management and threatened species recovery.
Inbreeding in the South African cheetah metapopulation necessitates genetic supplementation. One captive population and the free‐roaming population show similar SNP profiles to the metapopulation, the other two captive populations are highly differentiated. Introducing a few individuals from all three captive populations was the most effective conservation intervention strategy. Forward‐time simulations can be used to better inform conservation strategies in metapopulations where genetic diversity is threatened.
Long-term monitoring of Low Mass X-ray Binaries (LMXBs) by the All Sky Monitor on board the Rossi X-ray Timing Explorer now covers ∼13 yr and shows that certain LMXB types display very long-term ...(approximately several to tens of years) quasi-periodic modulations. These time-scales are much longer than any ‘super-orbital’ periods reported hitherto and likely have a different origin. We suggest here that they are due to long-term variations in the mass-transfer rate from the donor, which are a consequence of solar-like magnetic cycles that lead to Porb changes (as proposed by Richman, Applegate & Patterson for similar long-term variations in cataclysmic variables). Atoll sources display much larger amplitude modulations than Z sources over these time-scales, presumably because Z sources are Eddington limited and hence unable to respond as readily as Atoll sources to fluctuations in the mass-transfer rate from the donor.
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