bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of uniformly excited sparse rectangular planar array for sidelobe suppression using multi‐objective optimisation algorithm
Authors: Zhang Chengyan , Fu Xiongjun , Chen Xu , Peng Shuilian , Min Xie
Published: July 2019

Here, the multi‐objective optimisation algorithm speed‐constrained multi‐objective particle swarm optimisation is applied to the synthesis of uniformly excited sparse‐rectangular planar array with low sidelobe level. Numerical simulations have been conducted to test the performance of multi‐objective optimisation algorithm when used in this synthesis problem, and resulting radiation patterns are compared with those from other existing synthesis algorithms in literatures. Comparative results illustrate that the proposed algorithm has obtained the lowest maximum sidelobe level (MSLL) in φ  = 0 plane (φ is the elevation angle) of radiation pattern combined with the lowest maximum MSLL in φ  = π /2 plane. In addition, convergence performance of the multi‐objective optimisation algorithm when used in this synthesis problem has also been investigated here.
Novel ISAR autofocusing method based on Bayesian inference
Authors: Bai Xueru , Wang Ge
Published: July 2019

To achieve well‐focused ISAR imaging with low signal‐to‐noise ratio (SNR), this study constructs a statistical model and derives an effective method for image autofocusing based on Bayesian inference. Particularly, hierarchical sparse‐promoting priors are imposed on the weights, which are conjugate to the likelihood. The method has closed‐form solution which facilitates computation. Experimental results have demonstrated the effectiveness of the method in low SNR and short aperture scenarios.
Three‐dimensional reconstruction of space rotating target based on narrow‐band radar networks
Authors: Wang Chao , Wen Shu L. , Ye Chun M.
Published: July 2019

The micro‐motion of space target is an important signature for classification and recognition, which has received great attention. Based on the micro‐Doppler signals from narrow‐band radar networks, this study proposes a three‐dimensional reconstruction method of space rotating target. First, the rotational plane projection model and the three‐dimensional structure construction model are built based on the micro‐Doppler analysis of rotating targets. Then, the rotational axis of the target is accurately estimated by exploiting the relationship of micro‐Doppler features of sub‐radars in the radar networks. Finally, under the constraint of the physical shape of a cone target, the target with arbitrary number scatters can be reconstructed by setting a cost function. Experiments verify the validity and accuracy of the proposed method.
BSBL‐based multiband fusion ISAR imaging
Authors: Xiong Di , Wang Junling , Zhao Lizhi , Gao Meiguo
Published: July 2019

Multiband fusion imaging can effectively improve the range resolution of inverse synthetic aperture radar (ISAR) imaging. In this study, the block sparse Bayesian learning (BSBL) method is applied to multiband fusion imaging to achieve high‐resolution ISAR imaging of a block‐structured target. The BSBL method is suitable for the ISAR imaging of numerous and continuous scatterers because it considers the block structure characteristics of the signal. The validity of the proposed method is verified by the simulation and real‐data experimental results.
Maximal Sustained Isokinetic Power at Exercise Intolerance is not Critical Power
Authors: Yong Stanley , Swisher Austin R. , Ferguson Carrie , Cannon Daniel T.
Published: July 2019

The asymptote of the hyperbolic power-duration relationship, critical power (CP), demarcates sustainable from non-sustainable exercise. CP is a salient parameter within the theoretical framework determining exercise tolerance. However, measuring CP is time consuming – typically 4 constant-power exercise tests to intolerance, or a 3-min all-out sprint is required.

To determine whether 30 s of maximal isokinetic cycling, immediately following the limit of tolerance, approximates CP.

Fifteen participants (7 women, 8 men, 23±5 yr, 71±12 kg, V̇O2peak 4.39±1.04 L·min−1; 61±9 mL·kg·min−1) completed 4 constant supra-CP exercise tests to intolerance. Each test was followed immediately by a 30 s maximal isokinetic effort at 80 rpm. Mean isokinetic power was compared to the known CP.

Mean±SD CP was 159±47 W (CI95 133, 185 W). Maximal isokinetic power immediately following intolerance was greater (p<0.05) than CP in all but one comparison (181±51 vs. 159±47 W; p>0.07). However, this closest estimation, following the longest duration constant-power test, resulted in 21 W of mean bias and wide limits of agreement (±84 W).

Isokinetic power measured immediately following intolerance consistently overestimated critical power. Thus, an adjunct of 30 s maximal isokinetic cycling immediately following the limit of tolerance does not approximate critical power.
Field Methods to Estimate Fat-free Mass in International Soccer Players
Authors: Nuñez F. Javier , Munguia-Izquierdo Diego , Petri Cristian , Suarez-Arrones Luis
Published: July 2019

Based on the high financial and logistical costs associated with the assessment of body composition with dual-energy X-ray absorptiometry (DXA), this study determined which field method has the best correlation with DXA data, and developed an equation to estimate fat-free mass (FFM) using the field anthropometric data in international soccer players. A total of 17 international soccer players participated in this study. DXA values provided a criterion measure of FFM. Correlation coefficients, biases, limits of agreement, and differences were used as validity measures, and regression analyses were used to develop the prediction equation. All field methods used to obtain FFM data showed positive correlations (r from 0.90–0.96) with DXA. Only the equation developed by Deurenberg et al. [6] showed no differences from DXA with a low bias. The main strength of this study was providing a valid and accurate equation to estimate FFM specifically in international soccer players.
Relative Contribution of Acetabular and Femoral Reconstruction to Prosthetic Joint Instability Risk after Primary Total Hip Arthroplasty
Authors: Ituarte Felipe , Aggarwal Ajay , Leary Emily V. , Hansen Benjamin J. , Keeney James A.
Published: July 2019

Prosthetic joint instability is a challenging concern for a minority of total hip arthroplasty (THA) patients. Placement of the acetabular component within the traditional safe zone does not eliminate dislocation, and the relative contribution of femoral length and offset to instability risk has not been well defined. The authors compared 53 dislocated primary THAs treated against an age- and gender-matched cohort of 134 stable primary THAs. Anteroposterior and cross-table lateral radiographs were used to determine whether reconstructions met targets for acetabular inclination (30–50 degrees), acetabular anteversion (5–30 degrees), femoral length (0–9.9 mm) and femoral offset (0–9.9 mm). Statistical analysis was performed to assess univariate and multivariate relationships with an instability event; statistical significance was set using a two-sided p-value < 0.05. Forty-seven (88.7%) of the dislocating hips had nonoptimal acetabular or femoral reconstructions. While a similar proportion of patients in the study and control groups had acetabular reconstruction within the safe zone (51.5 vs. 47.2%, p = 0.63) patients with unstable hips were more likely to have acetabular component inclination outside of the target zone (30.2 vs. 7.5%, p < 0.01), acetabular anteversion < 15 degrees (30.2 vs. 3.7%, p < 0.0001), reduced femoral length (35.9 vs. 3.7%, p < 0.0001), and reduced femoral offset (41.5 vs. 7.46%, p < 0.0001). Stepwise multivariate logistic regression was performed and identified femoral head size less than 32 mm (OR 2.9, 95% CI 1.4–6.2) and higher inclination angle (OR 1.1, 95% CI 1.04–1.2) as significant independent risk factors for hip instability. The authors' study findings suggest that insufficient acetabular anteversion, femoral length, and femoral offset reconstruction contribute significantly to instability risk following THA. Using a larger femoral head is protective, but should be balanced against long-term volumetric wear risk.
A Retrospective Analysis of Clinical and Laboratory Data of Patients with Factor VII Deficiency: A Single Centre Experience
Authors: Iwaniec Teresa , Zdziarska Joanna , Musiał Jacek , Sanak Marek
Published: July 2019

Bleeding phenotype in patients with congenital factor VII (FVII) deficiency is highly variable. No direct correlation between FVII activity and bleeding tendency is noted. The aim of this study was to analyse clinical and laboratory phenotype of patients with FVII deficiency treated in one haemophilia treatment centre in Little Poland. Clinical and laboratory data of 106 patients were collected retrospectively. Bleeding symptoms were evaluated according to the Bleeding Assessment Tool. The mean FVII activity was 19.5% (range: 1.0–49.2) and the mean prothrombin time (PT) was 29.7 seconds (range: 13.2–64.8), comparable in both sexes. Activity was lower than 1% in 6.6% of individuals. The average age at diagnosis (31.2 years; range: 1–76) did not correlate with FVII activity. Half of the patients were diagnosed incidentally, mostly due to routine PT measurement. The most frequently reported symptoms were gum, nose and tooth extraction bleeds. A total of 22.6% of patients remained asymptomatic and 60.4% never required replacement therapy. Thrombotic episodes were diagnosed in five women (4.7%). In conclusion, the clinical picture of the analysed group is similar to the previously described. It should be stressed that a significant risk of bleeds, including joint haemorrhages, can be expected in patients with mildest FVII deficiency (>26%) as well. The rate of thrombosis (4.7%) was similar to other reports, with all affected patients having strong prothrombotic risk factors or being intensively treated with FVII concentrate.
Geographical Variations in Patterns of DAPT Cessation and Two-Year PCI Outcomes: Insights from the PARIS Registry
Authors: Vogel Birgit , Chandrasekhar Jaya , Baber Usman , Mastoris Ioannis , Sartori Samantha , Aquino Melissa , Krucoff Mitchell W. , Moliterno David J. , Henry Timothy D. , Weisz Giora , Gibson C. Michael , Iakovou Ioannis , Kini Annapoorna S. , Farhan Serdar , Sorrentino Sabato , Faggioni Michela , Colombo Antonio , Steg Philippe Gabriel , Witzenbichler Bernhard , Chieffo Alaide , Cohen David J. , Stuckey Thomas , Ariti Cono , Dangas George D. , Pocock Stuart , Mehran Roxana
Published: July 2019

Background Data on geographical variations in dual antiplatelet therapy (DAPT) cessation and the impact on outcomes after percutaneous coronary intervention (PCI) are limited. We sought to evaluate geographical patterns of DAPT cessation and associated outcomes in patients undergoing PCI in the United States versus Europe.

Methods Analyzing data from the PARIS registry, we studied 3,660 U.S. patients (72.9%) and 1,358 European patients (27.1%) that underwent PCI with stent implantation. DAPT cessation was classified as physician-recommended discontinuation, interruption (< 14 days), or disruption due to bleeding or noncompliance. The primary endpoint was 2-year major adverse cardiovascular events (MACE) defined as a composite of cardiac death, stent thrombosis, myocardial infarction, or target lesion revascularization.

Results Cardiovascular risk factors were more common in the United States, whereas procedural complexity was greater in Europe. The incidence of 2-year DAPT discontinuation was significantly lower in U.S. versus European patients (30.7% vs. 65.6%; p < 0.001); however, rates of interruption (13.7% vs. 1.5%, p < 0.001) and disruption (17.7% vs. 5.1%, p < 0.001) were higher. DAPT discontinuation was associated with lower adjusted risk, whereas DAPT disruption was associated with greater risk for 2-year MACE, without interaction by region. After adjustment for baseline characteristics and DAPT cessation, 2-year MACE risk was not statistically different between regions (10.3% for Europe vs. 11.9% for U.S., adjusted hazard ratio 0.81, 95% confidence interval 0.65–1.01, p = 0.065).

Conclusion DAPT cessation patterns, along with clinical and angiographic risk, vary substantially between PCI patients in the U.S. versus Europe. Despite such differences, cardiovascular risk associated with DAPT cessation remains uniform.
Further Delineation of the TRAPPC6B Disorder: Report on a New Family and Review
Authors: Nair Pratibha , El-Bazzal Lara , Mansour Hicham , Sabbagh Sandra , Al-Ali Mahmoud Taleb , Gambarini Alicia , Delague Valerie , El-Hayek Stephany , Mégarbané André
Published: July 2019

Pathogenic variants in the TRAPPC6B gene were recently found to be associated in three consanguineous families, with microcephaly, epilepsy, and brain malformations. Here, we report on a 3.5-year-old boy, born to consanguineous Lebanese parents, who presented with developmental delay, lactic acidosis, postnatal microcephaly, and abnormal brain magnetic resonance imaging. By whole exome sequencing, a novel homozygous likely pathogenic variant in exon 1 of the TRAPPC6B gene (c.23T > A; [p.Leu8*]) was identified. A review of the clinical description and literature is discussed, pointing out the phenotypic heterogeneity associated with mutations in this gene.
Analytic gradients for the single-reference driven similarity renormalization group second-order perturbation theory
Authors: Wang Shuhe , Li Chenyang , Evangelista Francesco A.
Published: July 2019

We derive and implement analytic energy gradients for the single-reference driven similarity renormalization group second-order perturbation theory (DSRG-PT2). The resulting equations possess an asymptotic scaling that is identical to that of the second-order Møller–Plesset perturbation theory (MP2), indicating that the exponential regularizer in the DSRG equations does not introduce formal difficulties in the gradient theory. We apply the DSRG-PT2 method to optimizing the geometries of 15 small molecules. The equilibrium bond lengths computed with DSRG-PT2 are found similar to those of MP2, yielding a mean absolute error of 0.0033 Å and a standard deviation of 0.0045 Å when compared with coupled cluster with singles, doubles, and perturbative triples.
Plasmons and inter-band transitions of hexagonal close packed gold nanoparticles
Authors: Peng Siying , Meng Andrew C. , Braun Michael R. , Marshall Ann F. , McIntyre Paul C.
Published: July 2019

We report on surface plasmons in the visible range in hexagonal close-packed (HCP) gold nanoparticles, synthesized by metastable solidification of Au-Ge eutectic liquid catalyst droplets at the tips of germanium nanowires at the cessation of vapor-liquid-solid nanowire growth. Using 300 kV electrons in a transmission electron microscope in scanning transmission mode with deep subnanometer spatial resolution, we characterize plasmons and interband transitions. Compared to conventional face-centered cubic (FCC) gold nanoparticles, plasmons and interband transitions are observed at different energies in HCP gold nanoparticles. We confirm lattice parameters unique to HCP gold by convergent beam electron diffraction and x-ray diffraction. Energy dispersive spectroscopy measured in a scanning transmission electron microscope verifies minimal impurity concentration in the HCP gold nanoparticles. These experimental results confirm that HCP gold is structurally distinct from FCC plasmonic materials, and also exhibits different electronic and optical properties.
Non-Hermitian complementary acoustic metamaterials for lossy barriers
Authors: Craig Steven R. , Welch Phoebe J. , Shi Chengzhi
Published: July 2019

Complementary materials are designed for the suppression of strongly mismatched potential barriers to enhance wave transmission and reduce wavefront distortion through the barriers. In acoustics, complementary materials enable noninvasive brain imaging and the treatment of neural disorders by overcoming the high impedance mismatch layer that prevents ultrasound transmission. However, the porous skull layer possesses intrinsic loss that prohibits the effective use of complementary metamaterials alone. Here, we propose to apply a non-Hermitian complementary metamaterial (NHCMM) to counteract the impedance mismatch and energy attenuation effect of the skull to achieve high acoustic transmission at high frequencies. Our numerical study shows a near perfect, unidirectional transmission through the skull when the NHCMM is applied while preserving the imaging information and enhancing the acoustic energy at the focal point needed for focused ultrasound used for noninvasive therapies. The proposed acoustic NHCMM lays the foundation for noninvasive ultrasonic brain imaging through an intact skull by stimulating in-vivo deep brain circuitry research and treatments for neural disorders such as brain tumors and strokes.
Simultaneous evaluation of drift- and diffusion-induced spin-orbit fields in a (001) GaAs/AlGaAs two-dimensional electron gas
Authors: Saito Takahito , Aoki Asuka , Nitta Junsaku , Kohda Makoto
Published: July 2019

We experimentally investigate spatiotemporal dynamics of an electron spin ensemble in the coexistence of drift and diffusive spin motion in a (001) GaAs/AlGaAs two-dimensional electron gas. Electron spins simultaneously experience spin–orbit effective magnetic fields induced by each transport mechanism, resulting in the modulation of spin precession frequency. By employing scanning time-resolved Kerr rotation microscopy, we evaluate both drift and diffusion induced spin–orbit fields simultaneously from the spatiotemporal spin map. Based on the evaluated Rashba and Dresselhaus spin–orbit coefficients, we clarify the difference and the accuracy of the evaluated spin–orbit coefficients in each transport mechanism.
On the issue of neutron source development for a laser-driven nuclear-thermonuclear reactor
Authors: Dolgoleva G.V. , Lebo I.G.
Published: July 2019

We discuss the feasibility of developing a high-power thermonuclear neutron source driven by laser pulses. Using one-dimensional numerical simulations for targets made in the form of double-sided cones, for an absorbed Nd-laser energy of ∼ 1 MJ (at the second and third harmonics) and pulse duration of 10 – 20 ns it is possible to achieve a neutron yield at a level of 1016 – 1017 per shot. This neutron yield is a prerequisite to the commencement of work to develop a hybrid nuclear-thermonuclear reactor.
Role of spontaneous emission in the formation of the steady-state optical spectrum of a diode laser
Authors: Bogatov A.P. , Drakin A.E.
Published: July 2019

Based on Maxwell’s equations, we derive a van der Pol-type equation for self-oscillations in the cavity of a diode laser. Its solution is self-oscillations (lasing) even in the absence of spontaneous emission. This solution differs fundamentally from solutions obtained using rate equations containing an additional term in the form of spontaneous emission intensity. Taking into account spontaneous emission in the van der Pol model makes calculation results more realistic and allows one to find parameters characterising diode laser output coherence, including the spectral densities of laser light amplitude and phase fluctuations.
Biomass heat storage dampens diurnal temperature variations in forests
Authors: Meier Ronny , Davin Edouard L , Swenson Sean C , Lawrence David M , Schwaab Jonas
Published: July 2019

Observational evidence suggests that compared to non-forested areas, forests have a cooling effect on daytime land surface temperature (LST) and a warming effect on nighttime LST in many regions of the world, thus implying that forests dampen the diurnal temperature range. This feature is not captured by current climate models. Using the Community Land Model 5.0 (CLM5.0), we show that this diurnal behavior can be captured when accounting for biomass heat storage (BHS). The nighttime release of energy absorbed by the vegetation biomass during the day increases both nighttime LST and ambient air temperature in forested regions by more than 1 K. The daytime cooling is weaker than the nighttime warming effect, because the energy uptake by the biomass is compensated by a reduction in the turbulent heat fluxes during day. This diurnal asymmetry of the temperature response to BHS leads to a warming of daily mean temperatures, which is amplified during boreal summer warm extremes. Compared to MODIS, CLM5.0 overestimates the diurnal LST range over forested areas. The inclusion of BHS reduces this bias due to its dampening effect on diurnal LST variations. Further, BHS attenuates the negative bias in the nighttime LST difference of forest minus grassland and cropland, when compared to MODIS observations. These results indicate that it is essential to consider BHS when examining the influence of forests on diurnal temperature variations. BHS should thus be included in land surface models used to assess the climatic consequences of land use changes such as deforestation or afforestation.
Implementing land-based mitigation to achieve the Paris Agreement in Europe requires food system transformation
Authors: Lee Heera , Brown Calum , Seo Bumsuk , Holman Ian , Audsley Eric , Cojocaru George , Rounsevell Mark
Published: July 2019

Land-based mitigation, particularly through afforestation, reforestation and avoided deforestation, is an important component of the Paris Agreement to limit average global temperature increases to between 1.5 °C and 2 °C. However, the specific actions that would ensure sufficient carbon sequestration in forests remain unclear, as do their trade-offs against other land-based objectives. We use a regional integrated assessment model to identify the conditions under which European forests reach the extent required by mitigation targets. We compare stylised scenarios of changes in meat demand, bioenergy crop production, irrigation efficiency, and crop yield improvement. Only 42 out of 972 model simulations achieved minimum levels of food provision and forest extent without the need to change dietary preferences, but relied on crop yield improvements within Europe of at least 30%. Maintaining food imports at today’s levels to avoid the potential displacement of food production and deforestation required at least a 15% yield improvement, or a drastic reduction in meat consumption (avg. 57%). The results suggest that the large-scale afforestation/reforestation planned in European targets is virtually impossible to achieve without transformation of the food system, making it unlikely that Europe will play its required role in global efforts to limit climate change without utilising land beyond its borders.
A missing component of Arctic warming: black carbon from gas flaring
Authors: Cho Mee-Hyun , Park Rokjin J , Yoon Jinho , Choi Yonghan , Jeong Jaein I , Labzovskii Lev , Fu Joshua S , Huang Kan , Jeong Su-Jong , Kim Baek-Min
Published: July 2019

Gas flaring during oil extraction over the Arctic region is the primary source of warming-inducing aerosols (e.g. black carbon (BC)) with a strong potential to affect regional climate change. Despite continual BC emissions near the Arctic Ocean via gas flaring, the climatic impact of BC related to gas flaring remains uncertain. Here, we present simulations of potential gas flaring using an earth system model with comprehensive aerosol physics to show that increases in BC from gas flaring can potentially explain a significant fraction of Arctic warming. BC emissions from gas flaring over high latitudes contribute to locally confined warming over the source region, especially during the Arctic spring through BC-induced local albedo reduction. This local warming invokes remote and temporally lagging sea-ice melting feedback processes over the Arctic Ocean during winter. Our findings imply that a regional change in anthropogenic aerosol forcing is capable of changing Arctic temperatures in regions far from the aerosol source via time-lagged, sea-ice-related Arctic physical processes. We suggest that both energy consumption and production processes can increase Arctic warming.
Integrated policy assessment and optimisation over multiple sustainable development goals in Eastern Africa
Authors: Van de Ven Dirk-Jan , Sampedro Jon , Johnson Francis X , Bailis Rob , Forouli Aikaterini , Nikas Alexandros , Yu Sha , Pardo Guillermo , García de Jalón Silvestre , Wise Marshall , Doukas Haris
Published: July 2019

Heavy reliance on traditional biomass for household energy in eastern Africa has significant negative health and environmental impacts. The African context for energy access is rather different from historical experiences elsewhere as challenges in achieving energy access have coincided with major climate ambitions. Policies focusing on household energy needs in eastern Africa contribute to at least three sustainable development goals (SDGs): climate action, good health, and improved energy access. This study uses an integrated assessment model to simulate the impact of land policies and technology subsidies, as well as the interaction of both, on greenhouse gas (GHG) emissions, exposure to air pollution and energy access in eastern Africa under a range of socioeconomic pathways. We find that land policies focusing on increasing the sustainable output of biomass resources can reduce GHG emissions in the region by about 10%, but also slightly delay progress in health and energy access goals. An optimised portfolio of energy technology subsidies consistent with a global Green Climate Funds budget of 30–35 billion dollar, can yield another 10% savings in GHG emissions, while decreasing mortality related to air pollution by 20%, and improving energy access by up to 15%. After 2030, both land and technology policies become less effective, and more dependent on the overall development path of the region. The analysis shows that support for biogas technology should be prioritised in both the short and long term, while financing liquefied petroleum gas and ethanol technologies also has synergetic climate, health and energy access benefits. Instead, financing PV technologies is mostly relevant for improving energy access, while charcoal and to a lesser extend fuelwood technologies are relevant for curbing GHG emissions if their finance is linked to land policies. We suggest that integrated policy analysis is needed in the African context for simultaneously reaching progress in multiple SDGs.
Energy demand transitions and climate mitigation in low-income urban households in India
Authors: Khosla Radhika , Sircar Neelanjan , Bhardwaj Ankit
Published: July 2019

Growing household energy demand, particularly in developing countries starting from a low base of consumption, is an important driver of current and future greenhouse gas emissions. Yet, our understanding of transitioning residential energy demand in developing country contexts is limited. This paper discusses changing energy service demands in urban low-income households in India, an emerging economy where the largest future growth in energy demand globally is projected to occur, and where 12 million new low-income homes for the urban poor are to be built by the government between 2015 and 2022. Based on mixed quantitative and qualitative methods comprising of surveys, interviews and focus group discussions, we analyze two inter-related questions: how does the demand for energy services change as the ability of low-income households to consume increases; and how do energy related behaviors influence household electricity consumption? We analyze the data collected to rank households according to their ability to consume and to identify the types of, and progression in, energy services acquired. The appliances and associated services pursued are lights, fans, televisions, and refrigerators, with varied energy efficiencies. Analogously, we quantify the influence of behavior in determining electricity consumption, and show that the inclusion of socio-demographic and behavioral factors explain a significant proportion (51%) of the variance in household electricity consumption, along with the role of material factors such as building physical characteristics and appliance stocks. We complement the statistical analysis with qualitative fieldwork and discuss changing energy related behaviors as the ability of households to consume increases. We conclude with recommendations for climate actions that are compatible with development in the growing low-income housing stock.
Heat transport considerations in the mathematical analysis of the photoacoustic and photothermal effects
Authors: Gutiérrez-Reyes E , García-Segundo C , García-Valenzuela A , Ortega Roberto , Buj Christian , Filbir Frank
Published: July 2019

In this work, we solve the problem of modeling the generation of an acoustic pulse produced by the incidence of a pulsed laser light upon an elastic material. Our concern is about the heat transport during the absorption of electromagnetic radiation. We assume that the pulse duration is of the order of nanoseconds, and asses if under these conditions the contribution of the heat transport in the sample is an essential consideration in the description of the phenomena or if we can ignore it in the model. We begin with the energy balance analysis over the initial interaction of radiation with matter in the context of the formulation Meixner-Prigonine which is called the linear irreversible thermodynamics to describe the induced temperature field. Then we carry a momentum balance which yields the macroscopic elasticity equations with a heat source for the induced pressure field. Once established the equations for temperature and displacement fields, we solve them for the one-dimensional case, showing that the induced pressure has two components, one fast component and one slow component which is due to heat transport in the sample, which is one of the main contributions of the paper.
Positive entropy actions of countable groups factor onto Bernoulli shifts
Authors: Seward Brandon
Published: July 2019

We prove that if a free ergodic action of a countably infinite group has positive Rokhlin entropy (or, less generally, positive sofic entropy), then it factors onto all Bernoulli shifts of lesser or equal entropy. This extends to all countably infinite groups the well-known Sinai factor theorem from classical entropy theory.
On entropy of spherical twists
Authors: Ouchi Genki
Published: July 2019

In this paper, we compute categorical entropy of spherical twists. In particular, we prove that the Gromov–Yomdin-type conjecture holds for spherical twists. Moreover, we construct counterexamples of Gromov–Yomdin type conjecture for K3 surfaces modifying Fan’s construction for even higher-dimensional Calabi–Yau manifolds.

The appendix, by Arend Bayer, shows the nonemptiness of complements of a number of spherical objects in the derived categories of K3 surfaces.
A note on steady vortex flows in two dimensions
Authors: Cao Daomin , Wang Guodong
Published: July 2019

In this note, we give a general criterion for steady vortex flows in a planar bounded domain. More specifically, we show that if the stream function satisfies “locally” a semilinear elliptic equation with monotone or Lipschitz nonlinearity, then the flow must be steady.
Dimension-independent statistics of 𝐺𝑙_{𝑛}(𝔽_{𝕢}) via character polynomials
Authors: Gadish Nir
Published: July 2019

Picking permutations at random, the expected number of

k
k

-cycles is known to be

1

/

k

1/k

and is, in particular, independent of the size of the permuted set. This short note gives similar size-independent statistics of finite general linear groups: ones that depend only on small minors. The proof technique uses combinatorics of categories, motivated by representation stability, and applies simultaneously to symmetric groups, finite linear groups, and many other settings.
Open and cut: allosteric motion and membrane fission by dynamin superfamily proteins
Authors: Kalia Raghav , Frost Adam
Published: July 2019

Cells have evolved diverse protein-based machinery to reshape, cut, or fuse their membrane-delimited compartments. Dynamin superfamily proteins are principal components of this machinery and use their ability to hydrolyze GTP and to polymerize into helices and rings to achieve these goals. Nucleotide-binding, hydrolysis, and exchange reactions drive significant conformational changes across the dynamin family, and these changes alter the shape and stability of supramolecular dynamin oligomers, as well as the ability of dynamins to bind receptors and membranes. Mutations that interfere with the conformational repertoire of these enzymes, and hence with membrane fission, exist in several inherited human diseases. Here, we discuss insights from new x-ray crystal structures and cryo-EM reconstructions that have enabled us to infer some of the allosteric dynamics for these proteins. Together, these studies help us to understand how dynamins perform mechanical work, as well as how specific mutants of dynamin family proteins exhibit pathogenic properties.
The Effect on Fit of Multiple Consecutive Donning and Doffing of N95 Filtering Facepiece Respirators
Authors: Vuma Cynthia Danisile , Manganyi Jeanneth , Wilson Kerry , Rees David
Published: July 2019

Background

N95 filtering facepiece respirators (FFRs) are widely used in healthcare to reduce transmission of airborne infectious diseases. These respirators are generally described as single use or limited reuse devices, but cost and operational issues mean that they may be donned and doffed multiple times. There is scant research on the effect of this practice on adequacy of fit.

Objective

The purpose of this study was to measure the effect on respirator fit of multiple donning and doffing of N95 FFRs.

Methods

This was an experiment in which 16 women and 9 men employed by the National Institute for Occupational Health (NIOH), Johannesburg, donned their same N95 FFR six times. All 25 were trained in the correct wearing of the devices before the experiment. Four models of respirators were used: the six who did not use respirators at work (novice subjects) were issued a 3M 1860 FFR and the others used their currently supplied one. During the experiment subjects donned their respirators under the supervision of the tester. Quantitative fit testing was done in the NIOH Occupational Hygiene laboratory after each donning according to the OSHA-Accepted Fit Test Protocol using the TSI PortaCount Pro+ Model 8038 Respirator Fit Tester. During the test, fit was measured after each of seven exercises and then an overall fit factor was computed. Only individuals who achieved an initial overall fit factor of ≥100 were allowed to continue participation in the study. Median overall fit factors were calculated for the 25 subjects for each donning and changes across them was examined using Wilcoxon rank sum tests. Men and women and frequent and infrequent users were compared across the six tests. Infrequent use was defined as subjects who wore respirators ≤ once per week, and novice subjects.

Results

Two subjects (8%) had an overall fit factor <100 at fit Test 2, 6 (24%) at Test 3, and 8 (32%) at Tests 4, 5, and 6. Thirteen respirator users (52%) achieved ≥100 throughout the fit testing, so 12 had at least one failure at either Tests 2–6. Five of the 12 subjects with at least one failure showed persistent failures on all subsequent donnings. Six subjects out of 12 (50%) who failed a fit test achieved an overall fit factor >100 at a subsequent test. There was a significant difference between the median first and sixth overall fit factors (195 versus 150; P = 0.0271), but not between the second and sixth (161 versus 150; P = 0.3584). Men and women had similar overall fit factors, but infrequent users had larger average overall fit factors than frequent users after all six donnings.

Conclusion

Forty-eight percent of study subjects failed at least one fit test after re-donning an N95 FFR. The fit test data suggest that donning practices probably accounted for the fit test failures. The 50% of subjects who produced overall fit factors ≥100 after a test of <100 supports this contention.
Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation
Authors: Joseph Leo , Drew Alex , Mason Ian J , Peters Jeffrey L
Published: July 2019

We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.
“Place” in the Small Stories of African American Elders: A Narrative Case Study
Authors: De Medeiros Kate , Etter-Lewis Gwendolyn
Published: July 2019

Background and Objectives

Although there is a rich literature on place and home within gerontology, few studies have considered how place acts as identity markers for older African Americans. Since narratives and stories represent ways of expressing self and identity through ordered talk, they offer an interesting way to consider how people age biographically such as through links between place and self.

Research Design and Methods

We analyzed small stories (i.e., stories that can appear as snippets of talk immersed within a larger narrative) from five African Americans (three women, two men, ages 78–93 years) to better understand “place” in the context of their lives.

Results

Overall, place in participants’ small stories was linked to the African American oral tradition and, for some, the Great Migration (1915–1970) from south to north. Place identity in the small stories therefore went beyond fond reminisce and instead became a type of resistance to dominant narratives of place.

Discussion and Implications

Studying small stories can therefore be an important tool in better understanding deeply personal experiences of place for under-represented elders.
Increased Risk of Anemia, Neutropenia, and Thrombocytopenia in People With Human Immunodeficiency Virus and Well-Controlled Viral Replication
Authors: Akdag Delal , Knudsen Andreas Dehlbæk , Thudium Rebekka Faber , Kirkegaard-Klitbo Ditte Marie , Nielsen Chivit , Brown Peter , Afzal Shoaib , Nordestgaard Børge G , Lundgren Jens , Nielsen Susanne Dam
Published: July 2019

Background

Prior to the introduction of combination antiretroviral therapy (cART), cytopenias were common in people with human immunodeficiency virus (PWH), but it is unknown if well-controlled HIV infection is a risk factor for cytopenia. In this study we aimed to determine if HIV infection is an independent risk factor for anemia, neutropenia, lymphocytopenia, and thrombocytopenia.

Methods

PWH with undetectable viral replication and absence of chronic hepatitis infection (n = 796) were recruited from the Copenhagen Comorbidity in HIV Infection (COCOMO) study and matched uninfected controls from the Copenhagen General Population Study (n = 2388). Hematology was analyzed in venous blood samples. Logistic regression analyses adjusted for age, sex, ethnicity, smoking status, alcohol, and high-sensitivity C-reactive protein were performed to determine possible associations between HIV and cytopenias.

Results

PWH had a higher prevalence of anemia (6.9% vs 3.4%, P < .001), neutropenia (1.3% vs 0.2%, P < .001), and thrombocytopenia (5.5% vs 2.7%, P < .001) compared with uninfected controls. HIV was independently associated with anemia-adjusted odds ratio (aOR) of 2.0 (95% confidence interval [CI], 1.4–3.0); neutropenia aOR, 6.3 (95% CI, 2.0–19.6); and thrombocytopenia aOR, 2.7 (95% CI, 1.8–4.2). No association was found between HIV and lymphocytopenia.

Conclusions

Cytopenia is rare in people with well-controlled HIV, but HIV remains a risk factor for anemia, neutropenia, and thrombocytopenia and requires ongoing attention and monitoring.
The H i velocity function: a test of cosmology or baryon physics?
Authors: Chauhan Garima , Lagos Claudia del P , Obreschkow Danail , Power Chris , Oman Kyle , Elahi Pascal J
Published: July 2019

Accurately predicting the shape of the H i velocity function (VF) of galaxies is regarded widely as a fundamental test of any viable dark matter model. Straightforward analyses of cosmological N-body simulations imply that the Λ cold dark matter (ΛCDM) model predicts an overabundance of low circular velocity galaxies when compared to observed H i VFs. More nuanced analyses that account for the relationship between galaxies and their host haloes suggest that how we model the influence of baryonic processes has a significant impact on H i VF predictions. We explore this in detail by modelling H i emission lines of galaxies in the shark semi-analytic galaxy formation model, built on the surfs suite of ΛCDM N-body simulations. We create a simulated ALFALFA survey, in which we apply the survey selection function and account for effects such as beam confusion, and compare simulated and observed H i velocity width distributions, finding differences of ≲ 50 per cent, orders of magnitude smaller than the discrepancies reported in the past. This is a direct consequence of our careful treatment of survey selection effects and, importantly, how we model the relationship between galaxy and halo circular velocity – the H i mass–maximum circular velocity relation of galaxies is characterized by a large scatter. These biases are complex enough that building a VF from the observed H i linewidths cannot be done reliably.
The diverse galaxy counts in the environment of high-redshift massive black holes in Horizon-AGN
Authors: Habouzit Mélanie , Volonteri Marta , Somerville Rachel S , Dubois Yohan , Peirani Sébastien , Pichon Christophe , Devriendt Julien
Published: July 2019

High-redshift quasars are believed to reside in highly biased regions of the Universe, where black hole growth is sustained by an enhanced number of mergers and by being at the intersection of filaments bringing fresh gas. This assumption should be supported by an enhancement of the number counts of galaxies in the field of view of quasars. While the current observations of quasar environments do not lead to a consensus on a possible excess of galaxies, the future missions JWST, WFIRST, and Euclid will provide new insights on quasar environments, and will substantially increase the number of study-cases. We are in a crucial period, where we need to both understand the current observations and predict how upcoming missions will improve our understanding of BH environments. Using the large-scale simulation Horizon-AGN, we find that statistically the most massive BHs reside in environments with the largest galaxy number counts. However, we find a large variance in galaxy number counts, and some massive BHs do not show enhanced counts in their neighbourhood. Interestingly, some massive BHs have a very close galaxy companion but no further enhancement at larger scales, in agreement with recent observations. We find that AGN feedback in the surrounding galaxies is able to decrease their luminosity and stellar mass, and therefore to make them unobservable when using restrictive galaxy selection criteria. Radiation from the quasars can spread over large distances, which could affect the formation history of surrounding galaxies, but a careful analysis of these processes requires radiative transfer simulations.
Wideband super-resolution imaging in Radio Interferometry via low rankness and joint average sparsity models (HyperSARA)
Authors: Abdulaziz Abdullah , Dabbech Arwa , Wiaux Yves
Published: July 2019

We propose a new approach within the versatile framework of convex optimization to solve the radio-interferometric wideband imaging problem. Our approach, dubbed HyperSARA, leverages low rankness, and joint average sparsity priors to enable formation of high-resolution and high-dynamic range image cubes from visibility data. The resulting minimization problem is solved using a primal-dual algorithm. The algorithmic structure is shipped with highly interesting functionalities such as preconditioning for accelerated convergence, and parallelization enabling to spread the computational cost and memory requirements across a multitude of processing nodes with limited resources. In this work, we provide a proof of concept for wideband image reconstruction of megabyte-size images. The better performance of HyperSARA, in terms of resolution and dynamic range of the formed images, compared to single channel imaging and the clean-based wideband imaging algorithm in the wsclean software, is showcased on simulations and Very Large Array observations. Our matlab code is available online on github.
Understanding the radio beam of PSR J1136+1551 through its single pulses
Authors: Oswald Lucy , Karastergiou Aris , Johnston Simon
Published: July 2019

The frequency widening of pulsar profiles is commonly attributed to lower frequencies being produced at greater heights above the surface of the pulsar; so-called radius-to-frequency mapping (RFM). The observer’s view of pulsar emission is a 1D cut through a 3D magnetosphere: we can only see that emission which points along our line of sight. However, by comparing the frequency evolution of many single pulses positioned at different phases, we can build up an understanding of the shape of the active emission region. We use single pulses observed with the Giant Metrewave Radio Telescope to investigate the emission region of PSR J1136+1551 and test RFM. Assuming that emission is produced tangential to the magnetic field lines and that each emission frequency corresponds to a single height, we simulate the single pulse profile evolution resulting from the canonical conal beam model and a fan beam model. Comparing the results of these simulations with the observations, we conclude that the emission region of PSR J1136+1551 is better described by the fan beam model. The diversity of profile widening behaviour observed for the single pulses can be explained by orthogonally polarized modes propagating along differing frequency-dependent paths in the magnetosphere.
New perspectives on the BOSS small-scale lensing discrepancy for the Planck ΛCDM cosmology
Authors: Lange Johannes U , Yang Xiaohu , Guo Hong , Luo Wentao , van den Bosch Frank C
Published: July 2019

We investigate the abundance, small-scale clustering, and galaxy–galaxy lensing signal of galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS). To this end, we present new measurements of the redshift and stellar mass dependence of the lensing properties of the galaxy sample. We analyse to what extent models assuming the Planck18 cosmology fit to the number density and clustering can accurately predict the small-scale lensing signal. In qualitative agreement with previous BOSS studies at redshift z ∼ 0.5 and with results from the Sloan Digital Sky Survey, we find that the expected signal at small scales ($0.1 \lt r_{\rm p}\lt 3 \, h^{-1}\, {\rm {Mpc}}$) is higher by $\sim 25{{\ \rm per\ cent}}$ than what is measured. Here, we show that this result is persistent over the redshift range 0.1 < z < 0.7 and for galaxies of different stellar masses. If interpreted as evidence for cosmological parameters different from the Planck cosmic microwave background (CMB) findings, our results imply $S_8 = \sigma _8 \sqrt{\Omega _{\rm m}/ 0.3} = 0.744 \pm 0.015$, whereas S8 = 0.832 ± 0.013 for Planck18. However, in addition to being in tension with CMB results, such a change in cosmology alone does not accurately predict the lensing amplitude at larger scales. Instead, other often neglected systematics like baryonic feedback or assembly bias are likely contributing to the small-scale lensing discrepancy. We show that either effect alone, though, is unlikely to completely resolve the tension. Ultimately, a combination of the two effects in combination with a moderate change in cosmological parameters might be needed.