Successful cryopreservation of African wild dog (Lycaon pictus) spermatozoa: towards developing the frozen zoo

Sperm freezing and artificial insemination can aid species management and conservation of the African wild dog (Lycaon pictus). Freezing attempts have previously been unsuccessful with sperm motility dropping to nearly 0% within 2 h of thawing. We examined the quality of wild dog spermatozoa subjected to 2 routine canine cryopreservation protocols: 1) 1-step dilution in TRIS-egg yolk extender containing 8% glycerol and 20% egg yolk; and 2) 2-step dilution in TRIS-egg yolk extender to a final concentration of 5% glycerol, 20% egg yolk and 0.5% Equex STM. Protocol 2 showed a significantly higher post-thaw viability, acrosome integrity and longevity of spermatozoa with motility present for up to 8 h after thawing; making it suitable for sperm banking and downstream use in species management by artificial insemination for the first time

Inviscid dynamical structures near Couette flow

Consider inviscid fluids in a channel {-1<y<1}. For the Couette flow v_0=(y,0), the vertical velocity of solutions to the linearized Euler equation at v_0 decays in time. At the nonlinear level, such inviscid damping has not been proved. First, we show that in any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow, there exist non-parallel steady flows with arbitrary minimal horizontal period. This implies that nonlinear inviscid damping is not true in any (vorticity) H^{s}(s<(3/2)) neighborhood of Couette flow and for any horizontal period. Indeed, the long time behavior in such neighborhoods are very rich, including nontrivial steady flows, stable and unstable manifolds of nearby unstable shears. Second, in the (vorticity) H^{s}(s>(3/2)) neighborhood of Couette, we show that there exist no non-parallel steadily travelling flows v(x-ct,y), and no unstable shears. This suggests that the long time dynamics in H^{s}(s>(3/2)) neighborhoods of Couette might be much simpler. Such contrasting dynamics in H^{s} spaces with the critical power s=(3/2) is a truly nonlinear phenomena, since the linear inviscid damping near Couette is true for any initial vorticity in L^2

Social dominance does not affect semen quality in African wild dogs (Lycaon pictus)

Sperm banking and artificial insemination could benefit conservation of endangered African wild dogs (AWD). However, it is not clear whether their strict dominance hierarchy causes subfertility in subdominant males that typically do not breed. Our study investigated the effect of dominance on male reproductive parameters including: faecal glucocorticoids (fGCMs) and androgens (fAMs), testis and prostate volume, preputial gland size, semen collection success, and the number, motility, morphology, viability, acrosome integrity (PSA-FITC), and DNA integrity (TUNEL) of spermatozoa collected by electroejaculation. Samples were obtained from n=12 captive AWDs (4 US packs) in the pre-breeding season and n=28 captive AWDs (n=11 from 4 US packs; n=17 from 3 Namibian packs) in the breeding season. Male hierarchy was clearly determined by behavioural observations in all but 1 Namibian pack. Data were grouped by dominance status and means compared by ANOVA or t-test. P≤0.05 was significant. In the pre-breeding season, there was no significant difference in body weight, fGCMs, fAMs, or prostate and testis volume between dominance groups. Semen was successfully collected from all alphas but only half the subdominants; with urine contamination negatively associated with dominance. Sperm quality was low (17.3 ± 10.2% total motility, 12.8 ± 8.5% progressive motility, 27.4 ± 11.5 x 106 ejaculated spermatozoa, 40.6 ± 9.8% normal morphology, 63.1 ± 5.1% viability, 72.6 ± 5.2% acrosome integrity) with no difference observed in any parameter except progressive motility and normal sperm morphology; which were significantly lower in subdominants (27.7 ± 16.8% vs. 0.0 ± 0.0% and 59.8 ± 13.0% vs. 21.4 ± 5.7%). From pre-breeding to breeding season, testis and prostate volume increased significantly; particularly in beta and gamma males respectively. Prostate volume was higher in alpha than beta males (16.0 ± 6.4 cm3 vs. 5.7 ± 1.4 cm3), but testis volume, body weight, fAMs and fGCMs did not differ between dominance groups (12.0 ± 0.9 cm3, 28.5 ± 0.8 kg, 0.51 ± 0.07 µg/g dry weight - DW, 30.6 ± 2.3 ng/g DW). Semen was successfully collected from 75% of males; with reduced urine contamination. Collection success, urine contamination and preputial gland size were not associated with dominance. Sperm quality improved with significantly greater number, viability, and total motility. However, sperm quality did not differ between dominance groups (47.4 ± 6.7% total motility, 30.5 ± 5.8% progressive motility, 32.3 ± 9.2 x 106 ejaculated spermatozoa, 50.9 ± 5.2% normal morphology, 74.4 ± 4.2% viability, 85.6 ± 3.0% acrosome integrity, 99.7 ± 0.1% DNA integrity). In conclusion, subdominant males are at higher risk of urine contamination and have lower sperm motility and normal morphology when semen is collected in the pre-breeding season. However, their semen is of similar quality to dominant males in the breeding season, indicating that reproductive suppression of subdominant males is only behavioural. Thus, AWD males of all social ranks in the breeding season are suitable candidates for sperm banking

A genetic management toolkit: hormonal and behavioural research towards the development of artificial insemination technology in the African wild dog (Lycaon pictus)

African wild dogs have a complex pack structure with separate male and female dominance hierarchies in which reproduction is typically exclusive to the alpha male and female. Current efforts to maintain genetic diversity involve translocation of live animals in captivity, a process that involves the combination of male and female single-sex groups to form a new social pack. Due to their complex social structure, such introductions are difficult: regularly leading to aggression and injuries to the animals. Moreover, this may not result in breeding among genetically valuable individuals if they do not become dominant. To overcome these translocation-associated problems of intra-pack aggression our team has studied a number of facets of basic reproduction as well as stress and behavioural management in African wild dogs with the goal of developing strategies for semen cryopreservation and artificial insemination as a key to the introduction of new genes into existing stable packs (Van den Berghe et al. 2012, Anim Reprod Sci 133, 1-9). We began by establishing detailed reproductive and adrenal hormone profiles from multiple females in several reproductive states in both captive and free-ranging populations. Faecal samples from captive females in four European institutions and from wild males and females in South Africa were analysed for oestradiol, progestagens, testosterone and glucocorticoids. Captive data demonstrated that female wild dogs have reproductive characteristics similar to other canids, such as spontaneous ovulation and obligate pseudopregnancy. Almost all adult females became pseudopregnant, implying that the mechanism of reproductive suppression in this sex is likely to be behavioural rather than physiological. This was supported by data from free-ranging populations. Adrenal activity in captive and free-ranging animals was measured by faecal cortisol metabolites. Captive females had higher concentrations than free-ranging females. Glucocorticoid concentrations were more variable in captive individuals, whereas in both wild males and females, they were highest during gestation and denning. Adrenal activity in males, but not females, was also affected by age, with the highest glucocorticoid concentrations measured in yearlings. We have also investigated the use of dog appeasing pheromone (DAP) collars to down-regulate aggression associated with the formation of new packs in captivity. Our initial findings indicate that DAP may reduce baseline stress levels in females and, when applied during regrouping of same-sex individuals, results in a relative reduction in observed levels of aggression. Building on these findings, work is underway to develop a semen bank and artificial insemination techniques. Although reproductive suppression in females is likely to be behavioural, the effect of dominance on male fertility is still unresolved. We have begun investigating the relationship between hierarchy and sperm quality across the seasons. This will guide our development of a robust semen collection and freezing protocol that will permit the establishment of a high-quality semen bank. We are also progressing with non-invasive techniques to predict ovulation for timed artificial insemination of females. These techniques must first be established in captivity before our ultimate goal to implement them as tools for genetic meta-population management in semi-captive and free-ranging populations

Influence of scattering processes on electron quantum states in nanowires

In the framework of quantum perturbation theory the self-consistent method of calculation of electron scattering rates in nanowires with the one-dimensional electron gas in the quantum limit is worked out. The developed method allows both the collisional broadening and the quantum correlations between scattering events to be taken into account. It is an alternativeper seto the Fock approximation for the self-energy approach based on Green’s function formalism. However this approach is free of mathematical difficulties typical to the Fock approximation. Moreover, the developed method is simpler than the Fock approximation from the computational point of view. Using the approximation of stable one-particle quantum states it is proved that the electron scattering processes determine the dependence of electron energy versus its wave vector

Integration of fluorescence collection optics with a microfabricated surface electrode ion trap

We have successfully demonstrated an integrated optical system for collecting the fluorescence from a trapped ion. The system, consisting of an array of transmissive, dielectric micro-optics and an optical fiber array, has been intimately incorporated into the ion-trapping chip without negatively impacting trapping performance. Epoxies, vacuum feedthrough, and optical component materials were carefully chosen so that they did not degrade the vacuum environment, and we have demonstrated light detection as well as ion trapping and shuttling behavior comparable to trapping chips without integrated optics, with no modification to the control voltages of the trapping chip.Comment: 14 pages, 12 figure

Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: A systematic analysis for the Global Burden of Disease Study 2015

Background: The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods: We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings: Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation: Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding: Bill & Melinda Gates Foundation

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society