The Herschel-Quincke tube with modulated branches

The Herschel-Quincke (HQ) tube concept for transmission loss in pipe systems is expanded to include cases of branches with modulated properties. Modulated waveguides, featuring corrugations in their geometry or speed of sound, are known to produce significant reflection even without the parallel branch of the HQ tube. The HQ tube, in its classical form, produces narrow banded transmission loss at frequencies related to the length, wavenumber and cross-section area of the parallel branch. The modulated Herschel-Quincke (MHQ) tube combines these attributes to produce enhanced transmission loss characteristics in terms of both width and number of transmission loss bands. Several modulated profiles for the speed of sound in different branches of the tube are considered and analytical expressions for the transmission loss and resonant conditions are derived. Detailed analysis of periodically stratified branch profiles demonstrates the effectiveness of the MHQ tube for fluid-borne noise attenuation in pipe systems. This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 2)'

Body Fat Estimation from Surface Meshes using Graph Neural Networks

Body fat volume and distribution can be a strong indication for a person's overall health and the risk for developing diseases like type 2 diabetes and cardiovascular diseases. Frequently used measures for fat estimation are the body mass index (BMI), waist circumference, or the waist-hip-ratio. However, those are rather imprecise measures that do not allow for a discrimination between different types of fat or between fat and muscle tissue. The estimation of visceral (VAT) and abdominal subcutaneous (ASAT) adipose tissue volume has shown to be a more accurate measure for named risk factors. In this work, we show that triangulated body surface meshes can be used to accurately predict VAT and ASAT volumes using graph neural networks. Our methods achieve high performance while reducing training time and required resources compared to state-of-the-art convolutional neural networks in this area. We furthermore envision this method to be applicable to cheaper and easily accessible medical surface scans instead of expensive medical images

The 2003-4 multisite photometric campaign for the Beta Cephei and eclipsing star 16 (EN) Lacertae with an Appendix on 2 Andromedae, the variable comparison star

A multisite photometric campaign for the Beta Cephei and eclipsing variable 16 Lacertae is reported. 749 h of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with ten telescopes during 185 nights. After removing the pulsation contribution, an attempt was made to solve the resulting eclipse light curve by means of the computer program EBOP. Although a unique solution was not obtained, the range of solutions could be constrained by comparing computed positions of the secondary component in the Hertzsprung-Russell diagram with evolutionary tracks. For three high-amplitude pulsation modes, the uvy and the Geneva UBG amplitude ratios are derived and compared with the theoretical ones for spherical-harmonic degrees l <= 4. The highest degree, l = 4, is shown to be incompatible with the observations. One mode is found to be radial, one is l = 1, while in the remaining case l = 2 or 3. The present multisite observations are combined with the archival photometry in order to investigate the long-term variation of the amplitudes and phases of the three high-amplitude pulsation modes. The radial mode shows a non-sinusoidal variation on a time-scale of 73 yr. The l = 1 mode is a triplet with unequal frequency spacing, giving rise to two beat-periods, 720.7 d and 29.1 yr. The amplitude and phase of the l = 2 or 3 mode vary on time-scales of 380.5 d and 43 yr. The light variation of 2 And, one of the comparison stars, is discussed in the Appendix.Comment: 18 pages, 19 figures, accepted for publication in MNRA

Spreading of melts

Several mathematical problems that related to the flow and solidification of a hot fluid are studied. The fracture of the crust that forms as the fluid solidifies is also examined

Crack Front Waves and the dynamics of a rapidly moving crack

Crack front waves are localized waves that propagate along the leading edge of a crack. They are generated by the interaction of a crack with a localized material inhomogeneity. We show that front waves are nonlinear entities that transport energy, generate surface structure and lead to localized velocity fluctuations. Their existence locally imparts inertia, which is not incorporated in current theories of fracture, to initially "massless" cracks. This, coupled to crack instabilities, yields both inhomogeneity and scaling behavior within fracture surface structure.Comment: Embedded Latex file including 4 figure

Asteroseismology of the Beta Cephei star 12 (DD) Lacertae: photometric observations, pulsational frequency analysis and mode identification

We report a multisite photometric campaign for the Beta Cephei star 12 Lacertae. 750 hours of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with 9 telescopes during 190 nights. Our frequency analysis results in the detection of 23 sinusoidal signals in the light curves. Eleven of those correspond to independent pulsation modes, and the remainder are combination frequencies. We find some slow aperiodic variability such as that seemingly present in several Beta Cephei stars. We perform mode identification from our colour photometry, derive the spherical degree l for the five strongest modes unambiguously and provide constraints on l for the weaker modes. We find a mixture of modes of 0 <= l <= 4. In particular, we prove that the previously suspected rotationally split triplet within the modes of 12 Lac consists of modes of different l; their equal frequency splitting must thus be accidental. One of the periodic signals we detected in the light curves is argued to be a linearly stable mode excited to visible amplitude by nonlinear mode coupling via a 2:1 resonance. We also find a low-frequency signal in the light variations whose physical nature is unclear; it could be a parent or daughter mode resonantly coupled. The remaining combination frequencies are consistent with simple light-curve distortions. The range of excited pulsation frequencies of 12 Lac may be sufficiently large that it cannot be reproduced by standard models. We suspect that the star has a larger metal abundance in the pulsational driving zone, a hypothesis also capable of explaining the presence of Beta Cephei stars in the LMC.Comment: 12 pages, 7 figures, MNRAS, in pres

Факторы риска венозных и артериальных тромбозов у молодых женщин вне беременности

Introduction: to assess the influence of factors independently associated with arterial and venous thrombosis in women aged 18-44 years outside pregnancy.Material and methods. The case-control study included 319 women: the cases group included 134 patients with verified arterial and venous thrombosis, the control group included 185 patients without thrombosis. inclusion criteria: age 18-44 years; the presence of the first episode of instrumental^ verified arterial or venous thrombosis; consent to participate in the study. Exclusion criteria: pregnancy; the postpartum period up to 6 weeks at the time of thrombosis; mental disorders and mental illness. All women underwent clinical examination, collection of somatic and obstetric history, testing for biochemical parameters, hereditary and acquired thrombophilia. To quantify the independent relationships of risk factors with thrombotic events, the multiple logistic regression method was used.Results. In the group of cases, venous thrombosis was in 75% women, arterial thrombosis - in 25%. Ischemic strokes prevailed in the structure of arterial thrombosis. The most common trigger was the use of estrogen-progestin containing contraceptives in combination with other risk factors. In 23 cases (17.2%) the thrombosis were unprovoked. The proportion of women ≥ 40 years old, smoking intensity; family history of VTE in relatives up to 50 years of age, dyslipidemia, hyperfibrinogenemia, comorbidity, and the presence of thrombophilia met with a higher frequency in the group of cases. Independent factors associated with the development of arterial and venous thrombosis in young women were: the presence of diseases of the gallbladder (OR = 12,1 95% CI 2.5-67.5), cardiovascular diseases (OR = 10.2; 95% CI 3.6-29.1); total cholesterol level (OR = 7.7; 95% CI 4.4-13.5); respiratory diseases (OR = 3.7; 95% CI 1.0-11.5); the use of combined hormonal contraceptives (OR = 3.4; 95% CI 1.7-6.8); varicose veins of the lower extremities (OR = 2.5; 95% CI 1.0-4.9).Conclusion. The identification of the most important risk factors for arterial and venous thrombosis will expand the understanding of the common pathogenetic way of thrombosis in a population of women of childbearing age and improve their personalized prognosis and early prevention.Цель исследования: оценить влияние факторов, независимо ассоциированных с артериальными и венозными тромбозами у женщин в возрасте 18-44 лет вне беременности.Материалы и методы. В исследование по типу «случай - контроль» были включены 319 женщин: в группу «Случаи» вошли 134 пациентки с верифицированными артериальными и венозными тромбозами, в «Контроль» - 185 пациенток без тромбозов. Критерии включения: возраст 18-44 лет; наличие первого эпизода инструментально верифицированного артериального или венозного тромбоза; согласие на участие в исследовании. Критерии исключения: беременность, установленная акушером-гинекологом, на момент развития тромбоза и/или положительные результаты теста на бета-ХГЧ; послеродовый период до 6 недель на момент развития тромбоза; ментальные расстройства и психические заболевания, затрудняющие контакт. Всем женщинам осуществлялся клинический осмотр, сбор соматического и акушерского анамнеза, анализ медицинской документации, биохимическое исследование, тестирование на наследственные и приобретенные тромбофилии. Для количественной оценки независимых взаимосвязей факторов риска с тромботическими событиями использован метод множественной логистической регрессии.Результаты. В структуре преобладали венозные тромбозы (75%), артериальные тромбозы (25%) были преимущественно представлены ишемическими инсультами, инфаркт миокарда был у трех пациенток (2,2%). Наиболее частым триггером тромбоза являлось применение комбинированных гормональных контрацептивов в сочетании с другими провоцирующими факторами. У 23 женщин (17,2%) триггер тромбоза установить не удалось. В группе «Случаи» оказалась значимо выше доля женщин ≥ 40 лет; интенсивность курения; большая частота отягощенного семейного анамнеза по ВТЭО до 50 лет у родственников 1-й линии родства, дислипидемии, гиперфибриногенемии, коморбидности, наличия тромбофилий высокого риска. Независимыми факторами, ассоциированными с развитием артериальных и венозных тромбозов у молодых женщин, оказались: наличие заболеваний желчного пузыря (ОШ = 12,1, 95% ДИ 2,5-67,5), наличие сердечно-сосудистых заболеваний (ОШ = 10,2; 95% ДИ 3,6-29,1); уровень общего холестерина (ОШ = 7,7; 95% ДИ 4,4-13,5); болезни органов дыхания (ОШ = 3,7; 95% ДИ 1,0-11,5); применение комбинированных гормональных контрацептивов (ОШ = 3,4 ДИ 1,7-6,8); варикоз вен нижних конечностей (ОШ = 2,5; 95% ДИ 1,0-4,9).Заключение. Выделение наиболее важных факторов риска для артериальных и венозных тромбозов позволит расширить понимание единых патогенетических процессов тромбообразования в популяции женщин фертильного возраста и совершенствовать их персонализированное прогнозирование и раннюю профилактику