583 research outputs found
Whip it good! Geographic consistency in male songs and variability in female songs of the duetting eastern whipbird Psophodes olivaceus
Geographic variation in male bird songs has been studied extensively, but there have been few investigations of geographic variation in female songs or sex differences in patterns of geographic variation. We compared patterns of variation in male and female songs of eastern whipbirds Psophodes olivaceus by analyzing recordings from 16 populations across the species’ geographic range in eastern Australia. We found remarkably different patterns of geographic variation between the sexes. Female eastern whipbird songs are easily categorized into discrete song types. Song types are shared between nearby females, but female songs show pronounced differences at a continental scale. In contrast, male eastern whipbird songs show high consistency throughout the species’ geographic range. All recorded males share the ability to transpose the frequency of the introductory whistle and most recorded males share the ability to vary the direction of the slope of the terminal whip crack. For eight of nine measured variables, female songs show significantly higher levels of variation than male songs. We discuss whether sex differences in dispersal, song learning strategies, and song function may explain these sex differences in patterns of song variation. We suggest that eastern whipbirds have experienced a decoupling of male and female song learning strategies and that the songs of each sex have responded to different selective pressures in the context of countersinging interactions. We speculate that consistency in male songs throughout the geographic range of eastern whipbirds may arise through female preference for males that perform large bandwidth whip cracks
Discovery Of A Rossby Wave In Jupiter's South Equatorial Region
A detailed study of the chevron-shaped dark spots on the strong southern equatorial wind jet near 7.5 deg S planetographic latitude shows variations in velocity with longitude and time. The chevrons move with velocities near the maximum wind jet velocity of approx.140 m/s, as deduced by the history of velocities at this latitude and the magnitude of the symmetric wind jet near 7 deg N latitude. Their repetitive nature is consistent with an inertia-gravity wave (n = 75-100) with phase speed up to 25 m/s, relative to the local flow, but the identity of this wave mode is not well constrained. However, high spatial resolution movies from Cassini images show that the chevrons oscillate in latitude with a approx.7-day period. This oscillating motion has a wavelength of approx.20 deg and a speed of approx.100 m/s, following a pattern similar to that seen in the Rossby wave plumes of the North Equatorial Zone, and possibly reinforced by it, though they are not perfectly in phase. The transient anticyclonic South Equatorial Disturbance (SED) may be a similar wave feature, but moves at slower velocity. All data show chevron latitude variability, but it is unclear if this Rossby wave is present during other epochs, without time series movies that fully delineate it. In the presence of multiple wave modes, the difference in dominant cloud appearance between 7 deg N and 7.5 deg S may be due to the presence of the Great Red Spot, either through changes in stratification and stability or by acting as a wave boundary
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The Classical Pink-Eyed Dilution Mutation Affects Angiogenic Responsiveness
Angiogenesis is the process by which new blood vessels are formed from existing vessels. Mammalian populations, including humans and mice, harbor genetic variations that alter angiogenesis. Angiogenesis-regulating gene variants can result in increased susceptibility to multiple angiogenesis-dependent diseases in humans. Our efforts to dissect the complexity of the genetic diversity that regulates angiogenesis have used laboratory animals due to the availability of genome sequence for many species and the ability to perform high volume controlled breeding. Using the murine corneal micropocket assay, we have observed more than ten-fold difference in angiogenic responsiveness among various mouse strains. This degree of difference is observed with either bFGF or VEGF induced corneal neovascularization. Ongoing mapping studies have identified multiple loci that affect angiogenic responsiveness in several mouse models. In this study, we used F2 intercrosses between C57BL/6J and the 129 substrains 129P1/ReJ and 129P3/J, as well as the SJL/J strain, where we have identified new QTLs that affect angiogenic responsiveness. In the case of AngFq5, on chromosome 7, congenic animals were used to confirm the existence of this locus and subcongenic animals, combined with a haplotype-based mapping approach that identified the pink-eyed dilution mutation as a candidate polymorphism to explain AngFq5. The ability of mutations in the pink-eyed dilution gene to affect angiogenic response was demonstrated using the p-J allele at the same locus. Using this allele, we demonstrate that pink-eyed dilution mutations in Oca2 can affect both bFGF and VEGF-induced corneal angiogenesis
Home blood pressure monitors owned by participants in a large decentralised clinical trial in hypertension:the Treatment In Morning versus Evening (TIME) study
Various home blood pressure monitors (HBPMs) are available to the public for purchase but only some are validated against standardised protocols. This study aimed to assess whether HBPMs owned by participants taking part in a clinical trial were validated models. The TIME study is a decentralised randomised trial investigating the effect of antihypertensive medication dosing time on cardiovascular outcomes in adults with hypertension. No HBPMs were provided to participants in this trial but patients were asked to report if they already owned one. We identified the model of HBPM reported by participants, then cross-referenced this against lists of validated HBPMs produced by dabl Educational Trust and the British and Irish Hypertension Society (BIHS). Of 21,104 participants, 10,464 (49.6%) reported their model of HBPM. 7464 (71.3%) of these participants owned a monitor that could be identified from the participants’ entry. Of these, 6066 (81.3%) participants owned a monitor listed as validated by either dabl (n = 5903) or BIHS (n = 5491). Some were listed as validated by both. 1398 (18.7%) participants owned an identifiable HBPM that lacked clear evidence of validation. 6963 (93.3%) participants owned an upper arm HBPM and 501 (6.7%) owned a wrist HBPM. Validated HBPMs had a higher median online retail price of £45.00 compared to £20.00 for HBPMs lacking clear evidence of validation. A significant number of participants own HBPMs lacking evidence of validation
Energy Expenditure and Enjoyment of Active Television Viewing
International Journal of Exercise Science 9(1): 64-76, 2016. This study examined energy expenditure and enjoyment during sedentary television viewing (SED-TV), stepping in place during television commercials (COMM-TV), and physical activity prompted by common character phrases/mannerisms within a television program (PA-TV). Adults (N=38, age: 27.0±8.0 years, BMI: 25.4±4.2 kg/m2) completed three 30-minute sessions in random order: SED-TV, COMM-TV, and PA-TV. Energy expenditure and heart rate were assessed during each session. Enjoyment was assessed after the initial experimental session and at completion of the study. Energy expenditure was greater in the active versus sedentary sessions (COMM-TV vs SED-TV: difference = 32.7±1.9 kcal, p3.0 METS was lower in SED-TV (median = 0 minutes) compared to COMM-TV [median = 4.0 minutes (Inter-Quartile Range: 0.8, 7.3)] (p50% of age-predicted maximal heart rate. Both COMM-TV and PA-TV were reported to be significantly more enjoyable than SED-TV. COMM-TV and PA-TV resulted in higher energy expenditure, more minutes of moderate intensity physical activity, and higher reported enjoyment compared to SED-TV. These findings have implications for reducing sedentary time during television viewing, which may impact health-related outcomes. Intervention trials are warranted to determine the effectiveness of these strategies
Infrared Variability of Two Dusty White Dwarfs
The most heavily polluted white dwarfs often show excess infrared radiation
from circumstellar dust disks, which are modeled as a result of tidal
disruption of extrasolar minor planets. Interaction of dust, gas, and
disintegrating objects can all contribute to the dynamical evolution of these
dust disks. Here, we report on two infrared variable dusty white dwarfs, SDSS
J1228+1040 and G29-38. For SDSS J1228+1040, compared to the first measurements
in 2007, the IRAC [3.6] and [4.5] fluxes decreased by 20% by 2014 to a level
also seen in the recent 2018 observations. For G29-38, the infrared flux of the
10 m silicate emission feature became 10% stronger between 2004 and 2007,
We explore several scenarios that could account for these changes, including
tidal disruption events, perturbation from a companion, and runaway accretion.
No satisfactory causes are found for the flux drop in SDSS J1228+1040 due to
the limited time coverage. Continuous tidal disruption of small planetesimals
could increase the mass of small grains and concurrently change the strength of
the 10 m feature of G29-38. Dust disks around white dwarfs are actively
evolving and we speculate that there could be different mechanisms responsible
for the temporal changes of these disks.Comment: ApJ, in pres
Reduced Sympathetic Innervation Underlies Adjacent Noninfarcted Region Dysfunction During Left Ventricular Remodeling
AbstractObjectives. We examined the association of sympathetic denervation and reduced blood flow with mechanical dysfunction in adjacent noninfarcted regions late after myocardial infarction (MI).Background. Using a well characterized ovine model of left ventricular (LV) remodeling after transmural anteroapical MI, we previously showed that histologically normal adjacent noninfarcted regions demonstrate mechanical dysfunction.Methods. Ten sheep underwent coronary ligation. Magnetic resonance imaging was performed before and 8 weeks after infarction for measurement of LV mass, volumes, ejection fraction and regional intramyocardial circumferential shortening (%S). Iodine-123 metaiodobenzylguanidine (I-123 MIBG) and fluorescent microspheres before and after administration of adenosine were infused before death for measurement of sympathetic innervation, blood flow and blood flow reserve from matched postmortem regions.Results. From baseline to 8 weeks after infarction, LV end-diastolic volume increased from (mean ± SD) 1.5 ± 0.3 to 2.6 ± 0.5 ml/kg (p < 0.001), and LV mass increased from 2.0 ± 0.3 to 2.6 ± 0.5 g/kg (p = 0.001). Regionally, the decline in subendocardial %S was greater in adjacent (19 ± 5% to 8 ± 5%) than in remote noninfarcted regions (20 ± 6% to 19 ± 6%, p < 0.002). No difference in regional blood flow or blood flow reserve was found between adjacent and remote regions, whereas I-123 MIBG uptake was lower in adjacent than in remote myocardium (1.09 ± 0.30 vs. 1.31 ± 0.40 nmol/g, p < 0.003). Topographically, from apex to base at 8 weeks after infarction, %S correlated closely with I-123 MIBG uptake (r = 0.93, p = 0.003).Conclusions. In mechanically dysfunctional noninfarcted regions adjacent to chronic transmural myocardial infarction in the remodeled left ventricle, blood flow and blood flow reserve are preserved, yet sympathetic innervation is reduced. Chronic sympathetic denervation in adjacent noninfarcted regions, in association with regional mechanical dysfunction, may contribute to LV remodeling after infarction
Factors influencing home blood pressure monitor ownership in a large clinical trial
Home blood pressure monitor (HBPM) ownership prevalence and the factors that influence it are unclear. This study aimed to investigate factors associated with HBPM ownership among participants in the Treatment in Morning versus Evening (TIME) hypertension study. This study is a sub-analysis of the TIME study, a randomised trial investigating the effect of day-time versus night-time dosing of antihypertensive medication on cardiovascular outcomes in adults with hypertension. As part of the TIME study online registration process, participants were asked to indicate whether they owned an HBPM. A multivariate logistic regression model was constructed to determine factors associated with HBPM ownership. Of 21 104 randomised participants, 11 434 (54.2%) reported owning an HBPM. The mean age of all participants at enrolment was 67.7 ± 9.3 years, 12 134 (57.5%) were male, and 8 892 (42.1%) reported a current or previous history of smoking. Factors associated with an increased likelihood of reporting HBPM owned include being male (OR:1.47; 95% CI 1.39-1.56) or residing in a less deprived socioeconomic region (IMD Decile 6-10) (OR:1.31; 95% CI 1.23-1.40). Participants with a history of diabetes mellitus (OR:0.74; 95% CI:0.64-0.86) or current smokers, compared to non-smokers, (OR:0.71; 95% CI:0.62-0.82) were less likely to report owning an HBPM. This study has identified important patient factors influencing HBPM ownership. Further qualitative research would be valuable to identify and explore potential patient-level barriers to engagement with self-monitoring of blood pressure
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