To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
In Assisted Reproductive Technologies (ART), efficient sperm preparation is vital for successful fertilization, with washing media enhancing the process. This pilot study examines the molecular-level impact of a new serotonin-containing sperm-washing medium (Prototype) on sperm motility and ROS metabolism, comparing it with commercially available media (Origio and Irvine). Semen samples from thirty-one individuals underwent preparation using the swim-up method post-semen analysis. Each sample was separately washed with the Prototype, Origio and Irvine mediums. ROS formation was determined through flow cytometric, and AT2R and PRDX2 protein levels, associated with sperm motility, were assessed via Western blot. Statistical evaluation compared the findings among the three outlined media. Significant differences were found among three washing media in terms of total and progressive motility. The Prototype medium showed the highest increase in both total (66%) and progressive motility (59%), while the control group exhibited the lowest increases (41% and 27.7%, respectively). Regarding ROS levels, the prototype (11.5%) and Origio (10.7%) groups demonstrated a notable decrease, contrasting with Irvine (25.8%). Molecular assessment revealed a significant elevation in AT2R protein levels in the prototype medium (59%), compared to other media. Additionally, an increase in PRDX2 protein levels was observed in the prototype medium, although this didn’t reach statistical significance. Serotonin-activated washing media for sperm preparation can be a suitable choice for selecting high-quality sperm in ART. A broader molecular analysis with a larger sample size is required to explore the mechanisms and effectiveness of using a serotonin-containing sperm-washing medium in routine ART.
This study investigated the association between screen time and ultra-processed food (UPF) consumption across the lifespan, using data from the 2019 Brazilian National Health Survey, a cross-sectional and population-based study. A score was used to evaluate UPF consumption, calculated by summing the positive answers to questions about the consumption of ten UPF subgroups on the previous day. Scores ≥5 represented high UPF consumption. Daily time spent engaging with television or other screens was self-reported. Crude and adjusted models were obtained through Poisson regression and results were expressed in prevalence ratios by age group. The sample included 2315 adolescents, 65 803 adults and 22 728 older adults. The prevalence of UPF scores ≥5 was higher according to increased screen time, with dose–response across all age groups and types of screen time. Adolescents, adults and older adults watching television for ≥6 h/d presented prevalence of UPF scores ≥5 1·8 (95 % CI 1·2, 2·9), 1·9 (95 % CI 1·6, 2·3) and 2·2 (95 % CI 1·4, 3·6) times higher, respectively, compared with those who did not watch television. For other screens, the prevalence of UPF scores ≥5 was 2·4 (95 % CI 1·3, 4·1) and 1·6 (95 % CI 1·4, 1·9) times higher for adolescents and adults using screens for ≥ 6 h/d, respectively, while for older adults, only screen times of 2 to < 3 and 3 to < 6 h were significantly associated with UPF scores ≥5. Screen time was associated with high consumption of UPF in all age groups. Considering these associations when planning and implementing interventions would be beneficial for public health across the lifespan.
In recent years, the significance of terahertz (THz) and (sub-)THz communications has grown substantially due to its promising trade-off between higher capacity compared to microwave-based communication and better resilience against weather dependent influences (e.g., fog and rain). While electronic and optoelectronic techniques have been extensively explored, each offering distinct advantages and limitations, they have predominantly been demonstrated and discussed as individual experiments, making performance comparison challenging. This paper addresses this gap by systematically benchmarking electronic and optoelectronic signal generation approaches under comparable conditions. Our experiments incorporate various receiver types, revealing that best performance is achieved by combining optoelectronic signal generation techniques at the transmitter in combination with an all-electric intradyne receiver. This results in a remarkable line rate of 200 Gbit/s over a distance of 52 m. To our knowledge, this represents the highest line rate achieved for technically relevant transmission distances for indoor access or outdoor small cell networks.
Prenatal detection of cardiac abnormalities has increased significantly over the past few decades, such that fetal cardiology has developed into a sub-specialty of paediatric and congenital cardiology. As this speciality develops further and extends across Europe and more globally, it is important to standardize the requirements for training and subsequent practice, to optimize prenatal diagnosis and perinatal care. In addition to the knowledge and technical skills required to make a correct diagnosis, the counseling of families after diagnosis and the planning of appropriate perinatal management is equally important. The aim of these recommendations is to provide a framework for both basic and advanced training for paediatric cardiologists wishing to practice as fetal cardiologists, as well as highlighting requisites for a fetal cardiology service. All aspects regarding training in fetal cardiology and service provision are addressed including diagnosis, counseling and management.
To assess whether isolated very low QRS voltage of ≤0.3 mV in the frontal leads might be a marker for diagnosing paediatric vasovagal syncope and the risk of recurrence.
Methods:
We included 118 children with vasovagal syncope, comprising 70 males and 48 females in our retrospective analysis. All patients underwent head-up tilt test and supine 12-lead electrocardiography. Furthermore, the QRS voltage was measured from each one of the 12 leads on basal electrocardiography. Patients were followed up for 6–24 months (average, 16 months).
Results:
Eighty-six patients (73%) patients displayed isolated very low QRS voltage in frontal leads. Furthermore, the patients were classified into two groups based on the presence or absence of isolated very low QRS voltage. Enhanced syncopic spells over the past 6 months, and the positive rates of head-up tilt test were observed in patients having isolated very low QRS voltage in the frontal leads than those without isolated very low QRS voltage (p < 0.05). The single factor and time-to-event analyses also showed an increased syncope recurrence rate in patients with isolated very low QRS voltage in frontal leads when compared with those without isolated very low QRS voltage (p < 0.01).
Conclusions:
Isolated very low QRS voltage in frontal leads is correlated with the positive response of the head-up tilt test in children who experience syncope and its recurrence post-treatment. Hence, isolated very low QRS voltage in frontal leads might become a novel diagnostic indicator and a risk factor for syncope recurrence in children with vasovagal syncope.
The nonlinear waves in a sheared liquid film on a horizontal plate at small Reynolds numbers are examined by theoretical and numerical approaches. The analysis employs the long-wave approximation along with finite difference schemes. The results show that the surface tension can suppress disturbances and prevent the occurrence of singularities. While the film flow is driven by the shear stress on the interface, its instability highly depends on the magnitude and direction of gravity. Specifically, when the direction of gravity is opposite to the wall-normal direction, perturbations are stabilized by gravity. In contrast, when these two directions are the same, the gravitational force is destabilizing, and stationary travelling waves can exist if a balance is reached between the effects of gravity and surface tension. For the steady solitary waves, there are quasi-periodic oscillations occurring between two stationary points, indicating the presence of heteroclinic trajectories. For periodic waves, the evolutions are sensitive to several parameters and initial disturbances, while one steady-state wave exhibits a sine function-like behaviour.
Understanding post-stroke spasticity (PSS) treatment in everyday clinical practice may guide improvements in patient care.
Methods:
This was a retrospective cohort study that used population-level administrative data. Adults (aged ≥18 years) who initiated PSS treatment (defined by the first PSS clinic visit, focal botulinum toxin injection, or anti-spasticity medication dispensation [baclofen, dantrolene and tizanidine] with none of these treatments occurring during the 2 years before the stroke) were identified between 2012 and 2019 in Alberta, Canada. Spasticity treatment use, time to treatment start and type of prescribing/treating physician were measured. Descriptive statistics were performed.
Results:
Within the cohort (n = 1,079), the most common PSS treatment was oral baclofen (initial treatment: 60.9%; received on/after the initial treatment date up to March 31, 2020: 69.0%), largely prescribed by primary care physicians (77.6%) and started a median of 348 (IQR 741) days after the stroke. Focal botulinum toxin (23.3%; 37.7%) was largely prescribed by physiatrists (72.2%) and started 311 (IQR 446) days after the stroke; spasticity clinic visits (18.6%; 23.8%) were also common.
Conclusions:
We found evidence of gaps in provision of spasticity management in persons with PSS including overuse of systemic oral baclofen (that has common adverse side effects and lacks evidence of effectiveness in PSS) and potential underuse of focal botulinum toxin injections. Further investigation and strategies should be pursued to improve alignment of PSS treatment with guideline recommendations that in turn will support better outcomes for those with PSS.
This paper presents a comprehensive evaluation of reduced-order models (ROMs) for the determination of pressure coefficient distributions on supersonic and hypersonic bodies. The study investigates the limitations, aerodynamic precision and computational performance associated with various methodologies, ranging from simplistic Newtonian theory-based approaches to more advanced first and second-order shock-expansion theories. Validation is performed by comparing computed results with experimental and computational data for pressure distributions, drag and lift coefficients and centres of pressure for fundamental geometries and authentic vehicle design over a wide range of freestream conditions. The study also includes a comprehensive computational complexity analysis, demonstrating the superiority of finite-element ROM approaches over traditional finite-volume computational fluid dynamics (CFD) simulations. The primary objective of this paper is to scrutinise the extension of these methodological classes to the low supersonic regime. Hence, thermo-chemical reactions within the flow are disregarded, and the ideal gas law is adopted. A value of $\gamma = 1.4$ is chosen for consistency and comparability across the analyses. The proposed ROMs show remarkable potential for reducing high-speed simulation execution times by four orders of magnitude, maintaining accuracy within 20 per cent and as low as 1 per cent. The study unveils three key findings: first, the accuracy degradation of Newtonian-based theories for inclined elements, particularly around 45 degrees, and their reduced dependency on Mach number at large inclination. Secondly, the study presents novel insights into the impact of shock-wave-Mach-wave interactions on pressure distribution calculations, emphasising the Mach number as a crucial metric governing recompression effects. Lastly, the study demonstrates the exceptional accuracy of DeJarnette’s method, providing ${C_P}$ results within 2 per cent for a wide range of conditions, offering an attractive alternative to the Taylor-Maccoll equation.
The axisymmetric nozzle mechanism is the core part for thrust vectoring of aero engine, which contains complex rigid-flexible coupled multibody system with joints clearance and significantly reduces the efficiency in modeling and calculation, therefore the kinematics and dynamics analysis of axisymmetric vectoring nozzle mechanism based on deep neural network is proposed. The deep neural network model of the axisymmetric vector nozzle is established according to the limited training data from the physical dynamic model and then used to predict the kinematics and dynamics response of the axisymmetric vector nozzle. This study analyses the effects of joint clearance on the kinematics and dynamics of the axisymmetric vector nozzle mechanism by a data-driven model. It is found that the angular acceleration of the expanding blade and the driving force are mostly affected by joint clearance followed by the angle, angular velocity and position of the expanding blade. Larger joint clearance results in more pronounced fluctuations of the dynamic response of the mechanism, which is due to the greater relative velocity and contact force between the bushing and the pin. Since axisymmetric vector nozzles are highly complex nonlinear systems, traditional numerical methods of dynamics are extremely time-consuming. Our work indicates that the data-driven approach greatly reduces the computational cost while maintaining accuracy, and can be used for rapid evaluation and iterative computation of complex multibody dynamics of engine nozzle mechanism.
This article examines the role of the mass media in driving anticartel debates during a coal crisis in Germany in 1900. Threatening the fuel supplies of millions of people, the nationwide energy shortage marked the beginning of the anticartel movement, adding a decisive thrust to antimonopoly sentiment toward the cartelized Ruhr coal industry. While hitherto overlooked, this symbolic chapter of German antimonopoly history was profoundly shaped by daily newspapers, a medium that revolutionized public communication during this period. By cross-referencing newspaper articles with records of the coal industry, this paper investigates how newspapers raised public concern for the fuel shortage and thereby forged narratives blaming the coal industrialists as well as how the coal producers responded to the ever-intensifying public scrutiny. As such, this study would serve to identify the mass media as a key determinant in the broader history of cartels and cartel politics in the twentieth century.
Aircraft play a major role in meeting the fast and efficient transportation needs of modern society, thanks to their advanced features. However, gas turbine engines used in aircraft have many negative effects on human health. One of the negative effects is the exhaust gases released by these engines to nature. In this study, it is discussed to present alternative models based on heuristic methods to reduce the emission values of the synthetic fuel mixture used in the combustion chamber of gas turbine engines. For this purpose, a model based on artificial neural networks (ANN) based on the back-tracking search optimisation (BSO) algorithm is proposed by using experimentally obtained emission values found in the literature. In the proposed model, the parameters of the optimum ANN structure are first determined by the BSO algorithm. Then, by using the optimum ANN structure, the most appropriate input values were found with the BSO algorithm, and the emission values were reduced. The simulation results have shown that the proposed method will be a fast and safe alternative method for reducing emission values.
Gripping devices for harvesting fruits have such types of work as cutting, tearing and unscrewing. For apples, it is preferable to use slicing or unscrewing, while the fruit leg should not remain, damaging the apple during storage. In this article, we are developing a grab for harvesting apples. The gripper is used both for holding the fruit and for jamming, followed by unscrewing. One of the advantages is that the proposed method of collecting apples allows you not to waste time moving the manipulator from the tree to the basket, but only to grab and tear them off. The fruit enters the gripper device; after which it enters the fruit collection container through a rigid or flexible pipe. The gripper device is built on the basis of a ball-screw transmission, which is supplemented by a gear drive along the helical surface. This allows for rotation and rectilinear movement of the held fruit. The gripping device has a ratchet mechanism that allows you to fix the fruit. A mathematical model of the gripper device has been developed, which allows determining the torque of the engine depending on the position of the fingers. The parameters of the mechanism were optimized using a genetic algorithm, and the results are presented in the form of a Pareto set. A 3D model of the gripper device has been built and a layout has been developed using 3D printing. Experimental laboratory and field tests of the gripping device were carried out.
We establish explicit constructions of Mahler’s p-adic $U_{m}$-numbers by using Ruban p-adic continued fraction expansions of algebraic irrational p-adic numbers of degree m.
This article distinguishes causal modeling, metaphysical, epistemic, and modeling reasons for variable/parameter choice. I argue in favor of justifying variable/parameter choices by appealing to modeling reasons concerning the limitations of the available measurements, experimental data, modeling techniques, and modeling frameworks. I use this “tyranny of availability” to identify normative criteria for variable/parameter choice that apply across most scientific modeling contexts and investigate their metaphysical and epistemological implications.
Traumatic Brain Injury (TBI) often leads to cognitive impairments, particularly regarding working memory (WM). This meta-analysis aims to examine the impact of TBI on WM, taking into account moderating factors which has received little attention in previous research, such as severity of injury, the different domains of Baddeley’s multi-component model, and the interaction between these two factors, as well as the interaction with other domains of executive functions.
Method:
Following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a systematic review and meta-analysis searched Google Scholar, PubMed, and PsycNET for studies with objective WM measures. Multiple meta-analyses were performed to compare the effects of TBI severity on different WM components. Twenty-four English, peer-reviewed articles, mostly cross-sectional were included.
Results:
TBI significantly impairs general WM and all Baddeley’s model components, most notably the Central Executive (d’ = 0.74). Severity categories, mild-moderate and moderate-severe, were identified. Impairment was found across severities, with “moderate-severe” demonstrating the largest effect size (d’ = 0.81). Individuals with moderate-severe TBI showed greater impairments in the Central Executive and Episodic Buffer compared to those with mild-moderate injury, whereas no such differences were found for the Phonological Loop and Visuospatial Sketchpad.
Conclusions:
These findings enhance our understanding of WM deficits in varying severities of TBI, highlighting the importance of assessing and treating WM in clinical practice and intervention planning.
Microorganism motility often takes place within complex, viscoelastic fluid environments, e.g. sperm in cervicovaginal mucus and bacteria in biofilms. In such complex fluids, strains and stresses generated by the microorganism are stored and relax across a spectrum of length and time scales and the complex fluid can be driven out of its linear response regime. Phenomena not possible in viscous media thereby arise from feedback between the swimmer and the complex fluid, making swimming efficiency co-dependent on the propulsion mechanism and fluid properties. Here, we parameterize a flagellar motor and filament properties together with elastic relaxation and nonlinear shear-thinning properties of the fluid in a computational immersed boundary model. We then explore swimming efficiency, defined as a particular flow rate divided by the torque required to spin the motor, over this parameter space. Our findings indicate that motor efficiency (measured by the volumetric flow rate) can be boosted or degraded by relatively moderate or strong shear thinning of the viscoelastic environment.
The new mineral vadlazarenkovite, ideally Pd8Bi1.5Te1.25As0.25, was discovered in a heavy concentrate obtained from ore samples collected at the Anomal’noe occurrence, Konder alkaline-ultrabasic massif, Khabarovsk Krai, Far East, Russia. It occurs as anhedral grains up to 0.15 × 0.15 mm, intergrown with vysotskite and associated with numerous platinum-group element (PGE) bearing minerals (arsenopalladinite, ezochiite, hollingworthite, kotulskite, norilskite, polarite, skaergaardite, sobolevskite, sperrylite, törnroosite, zvyagintsevite etc.). Vadlazarenkovite is grey, opaque with metallic lustre, has brittle tenacity and uneven fracture. No cleavage and parting are observed. The Vickers’ micro-indentation hardness (VHN, 50 g load) is 424 kg/mm2 (range 406–443, n = 4), corresponding to a Mohs’ hardness of 4.5–5. Dcalc. = 11.947 g/cm3. In reflected light, vadlazarenkovite is white with a pale creamy hue. The bireflectance is weak in air and noticeable in oil immersion. In crossed polars the new mineral exhibits distinct anisotropy in grey tones. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are (Rmin/Rmax, %): 47.2/47.8 (470 nm), 49.1/50.8 (546 nm), 50.7/52.6 (589 nm) and 52.4/54.6 (650 nm). The chemical composition (wt.%, electron microprobe data, mean of 6 analyses) is: Pd 63.67, Ag 2.21, As 1.27, Sb 0.60, Te 11.26, Pb 2.56, Bi 19.95, total 101.51. The empirical formula calculated on the basis of 11 atoms per formula unit is (Pd7.87Ag0.27)Σ8.14(Bi1.26Te1.16As0.22Pb0.16Sb0.06)Σ2.86. Vadlazarenkovite is trigonal, space group R$\bar 3$c, a = 7.7198(2), c = 43.1237(11) Å, V = 2225.66(13) Å3 and Z = 12. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 2.308 (55) (1 1 15); 2.262 (100) (2 0 14); 2.232 (70) (3 0 0); and 2.040 (70) (1 1 18). The crystal structure of vadlazarenkovite was refined to R1 = 0.0267 for 761 reflections with Fo > 4σ(Fo). The new mineral is isotypic with mertieite. It honours Professor Vadim Grigorievich Lazarenkov (1933–2014) for his outstanding contributions to the geology, geochemistry and mineralogy of platinum-group elements.
This paper presents a dual-band bandpass filter with regular harmonic suppression. The proposed third-order filter consists of two microstrip stepped impedance resonators and single substrate integrated waveguide resonator. The mismatches in their higher order resonant frequencies are utilized to suppress the regular harmonics. The passbands are centered at f1 = 2.4 GHz and f2 = 3.5 GHz with fractional bandwidths of 5% and 7.5%, respectively. The measured midband insertion and return losses are better than 2.55 and 14.5 dB for the first, whereas for the second band, they are better than 1.95 and 14 dB. The filter offers at least 33 dB suppression of first three higher order regular harmonics of f1 and f2.