Current Record Holder Research Articles

Changes in Race Performance During the Underwater Phases of a 200 m Bi-Fin Race Simulation After Application of Respiratory Muscle Training—A Case Study in the Current World Record Holder

Maximal athletic performance can be limited by various factors, including restricted respiratory function. These limitations can be mitigated through targeted respiratory muscle training, as supported by numerous studies. However, the full potential of respiratory training in competitive finswimming has not been fully investigated. This case study aims to evaluate the effects of eight-week respiratory muscle training (RMT) on performance variability during the underwater phases of a 200 m bi-fin race simulation in an elite finswimmer (current world record holder and multiple world championship medalist). Performance variability was assessed based on pre-test, inter-test, and post-test data. Each measurement included pulmonary function and swim performance evaluations. In this study, underwater performance parameters, such as distance, time, velocity, and number of kicks, were assessed using video analysis synchronized with race timing and evaluated using the Dartfish software. The swimmer followed a 28-day training program with an Airofit PRO™ respiratory trainer between tests, with daily sessions targeting both inspiratory and expiratory muscles. The training involved 6–10 min of targeted exercises per day. Significant improvements were observed in Wilcoxon’s paired-sample test between the pre-test and post-test results in terms of underwater distance (p = 0.012; d = 1.26), underwater time (p = 0.012; d = 1.26), and number of underwater kicks (p = 0.043; d = 1.01), resulting in a 14.23% longer underwater distance, 14.08% longer underwater time, and 14.94% increase in underwater kicks. Despite the increased distance and time, underwater velocity remained stable, indicating improved underwater performance efficiency. Despite some improvements, it is not possible to conclude that respiratory muscle training (RMT) can contribute to improved finswimming performance during the underwater phases of a 200 m bi-fin race simulation in this particular athlete’s case. Further research with a larger sample size is necessary to fully understand the impact of RMT on finswimming performance.

Quinoacridane[4]arenes─Very Large Conformationally Restricted Macrocycles.

Phenol-based macrocycles play a fundamental role in supramolecular chemistry, but their size has been rather limited. Here we report a novel class of very large, bowl-shaped macrocycles with a diameter of 21.8 Å. These quinoacridane[4]arenes are 150% larger than the current record holders, the acridane[4]arenes, and three times the size of resorcin[4]arene. We expect the quinoacridane[4]arenes to be a useful platform for the construction of molecular containers.

On the Spin Period Distribution of Millisecond Pulsars

Spin period distribution provides important clues to understand the formation of millisecond pulsars (MSPs). To uncover the intrinsic period distribution, we analyze three samples of radio MSPs in the Galactic field and globular clusters. The selection bias due to pulse broadening has been corrected but turns out to be negligible. We find that all the samples can be well described by a Weibull distribution of spin frequencies. Considering MSPs in the Galactic field or globular clusters and in isolation or binary systems, we find no significant difference in the spin distribution among these subpopulations. Based on the current known population of MSPs, we find that submillisecond pulsars are unlikely to be discovered by the Square Kilometre Array, although up to ∼10 discoveries of pulsars that spin faster than the current record holder of P = 1.4 ms are expected.

The search for the farthest quasar: consequences for black hole growth and seed models

ABSTRACT The quest for high-redshift quasars has led to a series of record-breaking sources, with the current record holder at z = 7.642. Here, we show how future detections of z > 8 quasars impact the constraints on the parameters for black hole growth and seed models. Using broad flat priors on the growth parameters (Eddington ratio $\, {f_{\rm Edd}}$, duty cycle ${\cal D}$, seed mass M•,seed, and radiative efficiency ϵ), we show that the large uncertainties in their determination decrease by a factor ∼5 when a quasar’s detection redshift goes from z = 9 to z = 12. In this high-redshift regime, ϵ tends to the lowest value allowed, and the distribution for M•,seed peaks well inside the heavy seed domain. Remarkably, two quasars detected at z > 7 with low accretion rates (J1243+0100 and J0313–1806) already tighten the available parameter space, requiring $M_{\rm \bullet , seed} \gt 10^{3.5} \, {\rm M_\odot }$ and ϵ < 0.1. The radiative efficiency is a crucial unknown, with factor ∼2 changes able to modify the predicted mass by ∼3 orders of magnitude already at z ∼ 9. The competing roles of inefficient accretion (decreasing ϵ) and black hole spin-up (increasing ϵ) significantly impact growth models. Finally, we suggest that yields currently predicted by upcoming quasar surveys (e.g. Euclid) will be instrumental for determining the most-likely seed mass regime. For example, assuming thin-disc accretion, a detection of a quasar with $M_\bullet \sim 10^{10} \, {\rm M_\odot }$ by z ∼ 9–10 would exclude the entire parameter space available for light seeds and dramatically reduce the one for heavy seeds.

Nascent exascale supercomputers offer promise, present challenges

Sometime next year, managers at the US Department of Energy’s (DOE) Argonne National Laboratory in Lemont, IL, will power up a calculating machine the size of 10 tennis courts and vault the country into a new age of computing. The $500-million mainframe, called Aurora, could become the world’s first “exascale” supercomputer, running an astounding 1018, or 1 quintillion, operations per second. Rows of cabinets hold incredible processing power for one of the world's best supercomputers, Summit, at Oak Ridge National Laboratory in TN. Exascale computing will surpass these existing computers by leaps and bounds. Image credit: Flickr/Oak Ridge National Laboratory, licensed under CC BY 2.0. Aurora is expected to have more than twice the peak performance of the current supercomputer record holder, a machine named Fugaku at the RIKEN Center for Computational Science in Kobe, Japan. Fugaku and its calculation kin serve a vital function in modern scientific advancement, performing simulations crucial for discoveries in a wide range of fields. But the transition to exascale will not be easy. “As these machines grow, they become harder and harder to exploit efficiently,” says Danny Perez, a physicist at Los Alamos National Laboratory in NM. “We have to change our computing paradigms, how we write our programs, and how we arrange computation and data management.” That’s because supercomputers are complex beasts, consisting of cabinets containing hundreds of thousands of processors. For these processors to operate as a single entity, a supercomputer needs to pass data back and forth between its various parts, running huge numbers of computations at the same time, all while minimizing power consumption. Writing programs for such parallel computing is not easy, and theorists will need to leverage new tools such as machine learning and artificial intelligence to make scientific breakthroughs. Given these challenges, researchers have …

Identification of superconductivity mechanisms and prediction of new materials using Density Functional Theory (DFT) calculations

Superconductivity at room temperature or higher is considered a fundamentally viable goal, which may bring significant benefits to society, if achieved. However, methods to predict and design new superconductors remain largely empirical, without extensive guidance from computational quantum chemistry techniques, such as Density Functional Theory (DFT). This paper presents our progress, using DFT, towards a predictive tool for superconductivity from knowledge of the crystal structure. Excellent correlations between predicted and experimentally determined values have been demonstrated for MgB2 under a wide range of external conditions, including isotopic forms, metal substitutions, pressure and temperature effects. Model ideas have recently been shown to work equally well for hydrogen sulphide (H3S), which is the current record holder for the highest Tc (at 200K), albeit requiring very high pressures (∼160 GPa). Consistent patterns across families of superconductors, as determined from DFT calculations, are emerging that suggest a method to predict Tc seems possible.

Gas outflows from the z = 7.54 quasar: predictions from the BlueTides simulation

Many theoretical models predict that quasar driven outflows account for the observed quenching of star formation in massive galaxies. There is growing observational evidence for quasar-launched massive outflows at z>6, while the details of outflow-host galaxy interaction remain obscure. In this paper, we study the feedback around the highest redshift quasar in the BlueTides simulation, the largest volume cosmological hydrodynamic simulation so far carried out. We present predictions for gas outflows around the brightest $z = 7.54$ quasar which hosts the most massive black hole in the simulation volume, which has grown to black hole mass $6.7\times 10^{8}{\rm M}_\odot$ consistent with the current record holder for high-z quasars. We introduce a method to identify and trace the gas outflowing from the halo. We find that the total mass of the outflow gas is about $3.6\times 10^{9}{\rm M}_\odot$, constituting 6\% of the total gas in the halo. The outflow gas contains a cold, dense molecular component with mass about $2.6\times 10^{8}{\rm M}_\odot$, that originates from the inner region of the halo, within a few kpc of the central black hole. The velocities of the outflow gas reach thousands of km/s, within which the molecular component has mass averaged outward radial velocity of $1300$ km/s, consistent with observations. The averaged outflow rate is about $200-300 {\rm M}_\odot/yr$, with the outflowing gas mainly in a hotter ($T \sim 10^7$ K) and lower density state than the average of the host halo gas.

Superion Conductor Na11.1Sn2.1P0.9Se12: Lowering the Activation Barrier of Na+ Conduction in Quaternary 1–4–5–6 Electrolytes

We report on the first quaternary selenide-based Na+ superionic solid electrolyte, Na11.1Sn2.1P0.9Se12 (further denoted as NaSnPSe), which shows virtually the same room temperature Na+ ion conductivity (3.0 mS/cm) as the current record holder for sulfide-based systems, Na11Sn2PS12 (denoted as NaSnPS), but with a considerably lower activation energy of 0.30 eV. Both electrolytes belong to the currently highly topical class of solids comprising group I, IV, V, and VI atoms, which we summarize as 1–4–5–6 electrolytes. Herein, they are compared to each other with regard to their structural characteristics and the resulting ion transport properties. The lower activation energy of Na+ ion transport in NaSnPSe is well in line with the results of speed of sound measurements, Raman spectroscopy, bond-valence site energy calculations, and molecular dynamics simulations, all of which point to a lower lattice rigidity and to weaker Na–chalcogen interactions as compared to NaSnPS.

An updated Type II supernova Hubble diagram

We present photometry and spectroscopy of nine Type II-P/L supernovae (SNe) with redshifts in the 0.045 ≲ z ≲ 0.335 range, with a view to re-examining their utility as distance indicators. Specifically, we apply the expanding photosphere method (EPM) and the standardized candle method (SCM) to each target, and find that both methods yield distances that are in reasonable agreement with each other. The current record-holder for the highest-redshift spectroscopically confirmed supernova (SN) II-P is PS1-13bni (z = 0.335−0.012+0.009), and illustrates the promise of Type II SNe as cosmological tools. We updated existing EPM and SCM Hubble diagrams by adding our sample to those previously published. Within the context of Type II SN distance measuring techniques, we investigated two related questions. First, we explored the possibility of utilising spectral lines other than the traditionally used Fe iiλ5169 to infer the photospheric velocity of SN ejecta. Using local well-observed objects, we derive an epoch-dependent relation between the strong Balmer line and Fe iiλ5169 velocities that is applicable 30 to 40 days post-explosion. Motivated in part by the continuum of key observables such as rise time and decline rates exhibited from II-P to II-L SNe, we assessed the possibility of using Hubble-flow Type II-L SNe as distance indicators. These yield similar distances as the Type II-P SNe. Although these initial results are encouraging, a significantly larger sample of SNe II-L would be required to draw definitive conclusions.

Permutationally Invariant Potential Energy Surfaces.

Over the past decade, about 50 potential energy surfaces (PESs) for polyatomics with 4-11 atoms and for clusters have been calculated using the permutationally invariant polynomial method. This is a general, mainly linear least-squares method for precise mathematical fitting of tens of thousands of electronic energies for reactive and nonreactive systems. A brief tutorial of the methodology is given, including several recent improvements. Recent applications to the formic acid dimer (the current record holder in size for a reactive system), the H2-H2O complex, and four protonated water clusters [H+(H2O)n=2,3,4,6] are given. The last application also illustrates extension to large clusters using the many-body representation.

Highly variable lifespan in an annual reptile, Labord\u2019s chameleon (Furcifer labordi)

Among tetrapods, the current record holder for shortest lifespan is Labord’s chameleon, Furcifer labordi. These reptiles from the arid southwest of Madagascar have a reported lifespan of 4–5 months during the annual rainy season and spend the majority of their life (8–9 months) as a developing embryo. This semelparous, annual life history is unique among tetrapods, but only one population (Ranobe) in the southernmost distribution range has been studied. We therefore investigated the potential for environmentally-dependent variability in lifespan in a population in Kirindy Forest, which has a much longer warm rainy season. While no adults were found after March in Ranobe, the disappearance of adults was delayed by several months in Kirindy. Our data also revealed sex-biased mortality, suggesting that females have a longevity advantage. Furthermore, we found that, after an unusually long previous rainy season, one female was capable of surviving until a second breeding season. Keeping F. labordi in cages under ambient conditions demonstrated that also males can also survive until the next season of activity under these conditions. Our study therefore revealed considerable variability in the extreme life history of this tetrapod that is linked to variation in ecological factors.

A Metal-Organic Framework with a Pore Size/Shape Suitable for Strong Binding and Close Packing of Methane.

Much effort has been devoted to develop new porous structures for methane storage. We report a new porous coordination framework showing exceptional methane uptakes (e.g. 263 v/v at 298 K and 65 bar) and adsorption enthalpies (21.6 kJ mol(-1)) as high as current record holders functionalized by open metal sites. Computational simulations demonstrated that the hierarchical pore structure consisting of single-wall nanocages has suitable sizes/shapes and organic binding sites to enforce not only strong host-methane and methane-methane interactions but also dense packing of methane molecules.

A Metal–Organic Framework with a Pore Size/Shape Suitable for Strong Binding and Close Packing of Methane

AbstractMuch effort has been devoted to develop new porous structures for methane storage. We report a new porous coordination framework showing exceptional methane uptakes (e.g. 263 v/v at 298 K and 65 bar) and adsorption enthalpies (21.6 kJ mol−1) as high as current record holders functionalized by open metal sites. Computational simulations demonstrated that the hierarchical pore structure consisting of single‐wall nanocages has suitable sizes/shapes and organic binding sites to enforce not only strong host–methane and methane–methane interactions but also dense packing of methane molecules.

MULTI-WAVELENGTH LIGHT CURVE MODEL OF THE ONE YEAR RECURRENCE PERIOD NOVA M31N 2008-12a

We present a theoretical light curve model of the recurrent nova M31N 2008-12a, the current record holder for the shortest recurrence period (1 yr). We combined interior structures calculated using a Henyey-type evolution code with optically thick wind solutions of hydrogen-rich envelopes, which give the proper mass-loss rates, photospheric temperatures, and luminosities. The light curve model is calculated for a 1.38 M_sun white dwarf (WD) with an accretion rate of 1.6 \times 10^{-7} M_sun yr^{-1}. This model shows a very high effective temperature (log T_ph (K) \geq 4.97) and a very small wind mass-loss rate (\dot M_wind \leq 9.3 \times 10^{-6} M_sun yr^{-1}) even at the maximum expansion of the photosphere. These properties are consistent with the faint optical peak of M31N 2008-12a because the brightness of the free-free emission is proportional to the square of the mass-loss rate. The model well reproduces the short supersoft X-ray turn-on time of 6 days and turnoff time of 18 days after the outburst. The ejecta mass of our model is calculated to be 6.3 \times 10^{-8} M_sun, corresponding to 37% of the accreted mass. The growth rate of the WD is 0.63 times the mass accretion rate, making it a progenitor for a Type Ia supernova. Our light curve model predicts a bright supersoft X-ray phase one or two days before the optical peak. We encourage detection of this X-ray flash in future outbursts.

Application of the Method of Molecular Voronoi–Dirichlet Polyhedra for Analysis of Noncovalent Interactions in Crystal Structures of Flufenamic Acid—The Current Record-Holder of the Number of Structurally Studied Polymorphs

Crystal chemical analysis of eight polymorphs of flufenamic acid (FFA, C14H10NO2F3)—the current record-holder of the number of structurally characterized polymorphic modifications—was carried out using the method of molecular Voronoi–Dirichlet polyhedra. It was proved that every polymorph of FFA, as every polymorph of the previous record-holder ROY (C12H9N3O2S), has a unique set of types of intra- and intermolecular noncovalent interactions.

The reliability and utility of high reported specific rotations: reports and predictions of molecules with extremely high specific rotations, and high specific rotations suggest revision of the structures of huperzines E′ and F′

A search of the literature for all compounds with [α]D>1000 found 13 molecules with reliably determined specific rotations in excess of 6500, as judged by comparison with DFT-calculated values of [α]D for the same compounds, with a maximum [α]D −11,560 for a decacyclic helicene quinone. Several reports of [α]Ds ranging from 10,000 to 44,000 were judged to be spurious. On the basis of similar computational studies, several molecules are proposed that should have very high [α]Ds but relatively modest visible absorptions, unlike the current record holders, which have strong absorption near the sodium D line. In addition, the search found two natural products, huperzines E′ and F′, that have large reported [α]Ds (−4750 and −3182, respectively), that are inconsistent with their structures. However, computational studies found epimers of the reported structures that possess [α]Ds consistent with the reported chiroptical data.

Substituent effects on zinc phthalocyanine derivatives: A theoretical calculation and screening of sensitizer candidates for dye-sensitized solar cells

A series of unsymmetrical phthalocyanine sensitizer candidates with different donor and acceptor substituents, namely ZnPcBPh, ZnPcBOPh, ZnPcBtBu, ZnPcBN(Ph)2, ZnPcBNHPh, ZnPcBNH2, ZnPcBNHCH3 and ZnPcBN(CH3)2, were designed and calculated using density functional theory (DFT) and time-dependent DFT calculations. The molecular orbital energy levels, the molecular orbital spatial distributions and the electronic absorption spectra of the ZnPcB series molecules were compared with those of TT7 and TT8 to reveal the substituent effects of different donor and acceptor groups on the phthalocyanine compounds and select good sesitizer candidates. The results show that some of these compounds have considerably smaller orbital energy gaps, red-shifted absorption bands and better charge-separated states, causing them to absorb photons in the lower energy region. Several new absorption bands emerge in the 400–600nm region, which makes it possible for them to become panchromatic sensitizers. This characteristic is superior to the phthalocyanine sensitizers reported previously, including the current record holder, PcS6. The sensitizer candidates screened in the current work are very promising for providing good performance and might even challenge the photon-to-electricity conversion efficiency record of 4.6% for phthalocyanine sensitizers.

Statistical study of the ISM of GRB hosts

AbstractGamma-ray burst (GRB) afterglows shine, during a brief period of time as the most luminous objects that can be detected in the Universe. They have been observed at almost any redshift, from our nearby environment (the nearest one, at z = 0.08) to the very distant Universe (the current record holder at z = 9.4). Their optical spectra are well reproduced by a clean, simple power law, making them ideal light houses to probe the interstellar medium of their host galaxies at any redshift. We have used the largest sample of GRB afterglow spectra collected to date to perform a statistical study of the interstellar medium in their host galaxies. By analysing the distribution of equivalent widths of the most prominent absorption features we evaluate the different types of environments that host GRBs and study their diversity.

Health consequences of exercise and inactivity: The endurance athlete: high aerobic capacity and improved longevity

Adaptations to the cardiovascular, pulmonary and skeletal muscle systems allow endurance athletes to perform exercise for prolonged periods and delay the onset of fatigue. These adaptations explain why the current men's marathon world record holder can run 42.195 km (26.2 miles) in a little over 2 hours at an average speed of over 20 km/h. The adaptations which enable sustained endurance performance also offer protection against many chronic diseases and increase average lifespan. For example, former cyclists who competed in the Tour de France before 1964 demonstrated a 17% increase in average longevity compared with the general population1. Therefore studying the elite endurance athlete can give us clues as to how partaking in regular physical activity, or failure to do so, alters disease risk and life expectancy.

Dynamic Cage Survey

A $(k, g)$-cage is a $k$-regular graph of girth $g$ of minimum order. In this survey, we present the results of over 50 years of searches for cages. We present the important theorems, list all the known cages, compile tables of current record holders, and describe in some detail most of the relevant constructions.