Anomalous Mass Research Articles

The modulation of westerlies‐monsoon interaction on climate over the monsoon boundary zone in East Asia

AbstractMonsoon boundary zone (MBZ) is a transitional zone between the arid Central Asia (ACA) and humid Asia monsoon area, located in North China‐Mongolia. During boreal summer, both the mid‐latitude westerlies and East Asian Summer monsoon (EASM) play essential roles in the precipitation variations in the MBZ, via causing anomalous cold air mass from the west and warm/humid air from the south to the MBZ. In this study, we defined a summer westerly index (SWI) over the key westerly domain (35°‐42.5°N, 80°‐100°E) and an EASM index (EASMI) over the key EASM domain (25°‐35°N, 107.5°‐125°E) to investigate westerlies‐monsoon interaction and their effect on MBZ climate. The results show that westerlies and EASM have a synergistic effect on the precipitation in the MBZ and this synergistic effect could be amplified by the westerlies‐monsoon interaction. The westerlies and EASM interaction could induce a local cyclonic anomaly in the MBZ, this cyclonic anomaly further intensifies the westerlies and monsoon flow through a dynamical amplification, favours the precipitation in the MBZ. The MBZ precipitation also contributes to maintain the cyclonic anomaly via the latent heating release. The interannual variability of westerlies is largely modulated by the mid‐latitude Silk Road pattern (SRP) and the meridional displacement of the Asian westerly jet (AWJ), and the EASM variability is mainly modulated by El Niño‐Southern Oscillation (ENSO), the combined effects from these mid‐latitude circulation systems and tropical SST contribute to the climate variability in MBZ.

Global observations of submesoscale coherent vortices in the ocean

Subsurface-intensified anticyclones are ubiquitous in the ocean, yet their impact on the large-scale transport of heat, salt and chemical tracers is poorly understood. These submesoscale coherent vortices (SCVs) can trap and advect waters thousands of kilometers away from the formation region, providing a transport pathway that is unresolved by low-resolution Earth System Models. However, knowledge of the importance of these eddies for the large scale circulation is hindered by the lack of systematic observations. Here, we take advantage of the global network of Argo floats to identify occurrences of these eddies, which appear as weakly stratified anomalous water masses with Gaussian-shaped vertical structures. We develop a general algorithm to detect subsurface eddies that have propagated away from their source region, and apply it to the database of Argo float profiles, resulting in roughly 4000 detections from more than 20 years of observations. We further group detections into regional populations to identify hot-spots of generation and mechanisms of formation. Analysis of regional SCV statistics reveals important sites of SCV generation in Eastern Boundary Upwelling Systems, marginal sea overflows, and mode water formation regions along major open-ocean fronts. Because of the heat and salt anomaly contained within their cores, SCV could leave a significant imprint on the hydrographic properties of water masses in regions of high SCV density.

How to produce isotope anomalies in mantle by using extremely small isotope fractionations: A process-driven amplification effect?

One of the most important foundations of chemical geodynamics is that isotope anomalies of radiogenic isotopes observed in mantle-derived samples after correcting for natural and instrumental mass-dependent fractionations are mainly caused by radioactive decay of reservoirs with different parent-daughter ratios. It often denies the possibility of mass-independent fractionation processes at high temperatures. Therefore, isotope anomalies with very small magnitudes (ppm-level), such as 182W, has been used to identify different mantle reservoirs, the time scales of their formation and potential core-mantle interactions. 182W anomalies are generally considered as the sole consequences of radioactivity and nucleosynthesis that could be explained via simple mixing models of multiple reservoirs. However, the nuclear field shift effect (NFSE), has proved to be capable of producing the “anomalous mass effect” especially for heavy metal isotope systems even under very high temperatures. Therefore, it is necessary to test whether such small NFSE-induced mass-independent isotope fractionations can be magnified during unique mantle evolutionary processes, such as multi-stage melting and crystallization, to produce the observed isotope anomalies in mantle-derived rocks. Here we design a multistage closed-system melting and crystallization evolution model (denoted as MC2-model), combined with ab-initio calculations and Monte Carlo simulations to test our hypothesis. Multi-stage melting and crystallization evolution can occur in magma chambers, during tectonic movements in the early earth, in complex partial melting processes or plume and its surrounding mantle. Our simulation results show that there is an amplification effect during such multi-stage evolution process. The final isotope fractionations are scaled as aN, where N is the total number of melting or crystallization processes and a is a factor that related to the evolution path and detailed melting or crystallization behaviors, such as partition coefficient (D) and degree of melting or crystallization (F). In other words, if a mantle source region experienced multi-stage melting, melt extraction and crystallization processes, the isotope effect will probably linearly magnified. Taking O and W isotopes as examples, we conduct a statistical analysis for the results of such multi-stage simulation experiments and concluded that some of the ppm-level 182W anomalies, both positive and negative observed in Archean mantle-derived and modern plume-derived samples might be explained by this way, but our model seems to have difficulty in explaining 17O anomalies observed in anorthosite and basalts. This study provides another perspective for the origin of isotope anomalies that are observed in mantle-derived samples.

Large-Scale Atmospheric Circulation Related to Frequent Rossby Wave Breaking near Japan in Boreal Summer

AbstractRossby wave propagation along the Asian jet during boreal summer, such as the Silk Road pattern, frequently causes wave breaking near the Asian jet exit region. This study examines the statistical relationship between interannual variability of the Rossby wave breaking frequency near Japan and large-scale atmospheric circulation during the boreal summer. The Rossby wave breaking frequency in the midlatitudes climatologically shows its maximum near Japan, and significantly increases during La Niña years. The upper-tropospheric circulation regressed onto the Rossby wave breaking frequency near Japan in August shows large-scale anomalous convergence from the tropical central to eastern Pacific and divergence around the Indian Ocean. The consequent northward anomalous divergent wind over Eurasia contributes to enhancement and northward shift of the Asian jet. The Asian jet also shows meridional meandering with a phase of anomalous anticyclonic circulation near Japan accompanied by the frequent Rossby wave breaking, which is associated with the Silk Road pattern. The frequent Rossby wave breaking is related to southwestward intrusion of anomalous low potential temperature air mass toward the subtropical western North Pacific associated with an enhanced mid-Pacific trough. West of the southwestward cold-air intrusion, enhanced cumulus convection is seen around the northern Philippines, and the Pacific–Japan pattern is significantly seen in the lower troposphere. This result is consistent with a previous study that revealed a linkage mechanism between the Rossby wave breaking near Japan and the Pacific–Japan pattern through dynamically induced ascent resulting in an intrusion of high potential vorticity associated with the Rossby wave breaking.

C1 hypertrophic lateral mass resection and occiput-C2 fusion.

This case involved a 6-year-old boy with Down syndrome, left C1 lateral mass hypertrophy, C1–2 rotatory subluxation, and spinal cord compression. He presented after falling down some stairs at his home. Torticollis, dysphagia, and speech delay were noted on examination. Vascular imaging showed impingement on the left vertebral artery by the anomalous C1 lateral mass. Through a posterior approach, the hypertrophic C1 lateral mass was resected, and an occiput–C2 fusion was performed. Postoperatively, his torticollis and brainstem symptoms were resolved.The video can be found here: https://youtu.be/1U0GLdw6c70

Spatial resolution limits of EPMA

The development of field emission EPMA, has significantly improved the lateral resolution of EPMA. Two strategies are available for achieving high spatial resolution, either low overvoltage or low voltage analysis. Determining the spatial resolution for a particular analysis is complex and depends on the voltage, spot size, beam current, density of the sample, X-rays analysed and the precision and sensitivity required. Monte carlo simulations can be used to evaluate the spatial resolution for different analytical conditions and samples, provided the minimum spot size achievable at the conditions is known. Spot size is important in determining lateral resolution, which initially improves with decreasing accelerating voltages, and then increases as the minimum spot size becomes more significant than the distance electrons travel. For trace elements, the requirement for precision and sensitivity demands either higher overvoltages increasing the volume from which X-rays are generated, and/or higher beam currents increasing the spot size. At low overvoltage or low voltage conditions many additional factors must be considered: carbon contamination, coat thickness, erosion of the carbon coat, the stability of the sample and the problems surrounding the measurement of soft X-ray lines including L-lines for first row transition metals. When analysing L-lines for quantifying first row transition metals, either calibration curves must be used, or the anomalous mass absorption and variations in the fluorescence yields from partial shell occupancy must be accounted for, by using fits to experimentally determined values. By taking these factors into consideration, high quality measurements can be performed.

Uncommon causes of nerve compression in the distal forearm

Nerve compression by anomalous masses located at the wrist and distal forearm is an infrequent condition. They may compress underlying structures in the carpal tunnel region, causing pain and paresthesias, which leads to the wrong diagnosis of carpal tunnel syndrome. We present three cases of patients with symptomatology and clinical tests compatible with compression of the median nerve in the carpal tunnel but whose physical examination showed a soft mass in the distal region of the forearm which was compressing the median nerve, as demonstrated by ultrasound evaluation. The reported cases of accessory muscles or lipomas described in the literature as causes of median nerve compression clinic are mainly described only after the surgical decompression of the carpal tunnel, due to the maintenance of residual symptoms. Careful examination with an ultrasound evaluation prior to surgery may help to identify these cases and help planning surgical treatment.

Two Interpolation Methods Using Multiply-Rotated Piecewise Cubic Hermite Interpolating Polynomials

AbstractTwo interpolation methods are presented, both of which use multiple Piecewise Cubic Hermite Interpolating Polynomials (PCHIPs). The first method is based on performing 16 PCHIPs on 8 rotated versions of the plot of the data versus an independent variable (such as pressure or time). These 16 PCHIPs are then used to form 8 interpolations of the original data, and finally, these 8 are averaged. When the original data are unevenly spaced with respect to the independent variable, we show that it is best to perform the Multiply-Rotated PCHIP (MR-PCHIP) method using the “data index” as the independent variable, and then to subsequently perform one last PCHIP of the data index with respect to the original independent variable. This MR-PCHIP method avoids the flat spots that are a feature of the PCHIP method when the data have multiple values approximately equal to a local extreme value. The MR-PCHIP interpolated data have continuous first derivatives at the data points. This method also avoids the unrealistic overshoots that can occur when using the standard cubic spline interpolation procedure. The second interpolation method is designed specifically for hydrographic data with the aim of minimizing the formation of unrealistic water masses by the interpolation procedure. This is achieved by applying a Piecewise Cubic Hermite Interpolating Polynomial to each of 8 rotations of the salinity versus temperature plot (Multiply-Rotated Salinity–Temperature PCHIP, MRST-PCHIP) with bottle number (that is, data index) as the vertical interpolating coordinate, thereby making the MRST-PCHIP method independent of the heave of a water column. This method is equivalent to interpolating in the salinity–temperature diagram, and MRST-PCHIP proves very effective at avoiding the production of anomalous water masses that otherwise occur when interpolating temperature and salinity separately.

Anomaly-based synoptic analysis on the Heavy Rain Event of July 2018 in Japan

The Heavy Rain Event of July 2018 caused huge social impact and economic losses in Japan. In this study, the anomaly-based synoptic analysis is applied to identify the features and structures of the anomalous synoptic systems during the event period. Results show that the heavy rainfall occurred along the trough of anomalous geopotential height (GPH) and the shear line of anomalous winds at the low troposphere. The anomalous synoptic analysis, by removing the temporal climatology from the total variables, can directly reflect the large-scale features of the event, which includes the actual position of the Baiu front, the pathway of anomalous moist air masses associated with anomalous synoptic systems such as the anomalies of Okhotsk cold high and the Northwest Pacific subtropical high. Meanwhile, the opposite signs between 200 and 850 hPa GPH anomalies, which matches observed rainfall records well, could be a good indicator of the potential heavy rain period. The product of the ensemble prediction systems from the European Centre for Medium-Range Weather Forecasts is able to predict such potential anomalous signals of the Heavy Rain Event for 4–5 days in advance.

Contrasting Centennial‐Scale Climate Variability in High Mountain Asia Revealed by a Tree‐Ring Oxygen Isotope Record From Lahaul‐Spiti

AbstractGlacier response analyses in High Mountain Asia have revealed that the glaciers from the Karakoram region were in balance or thickening while most from the other regions were thinning, the “Karakoram anomaly.” It is, however, not clear whether this contrasting glacier response in High Mountain Asia is the result of regionally varying climate trends. Here, we give evidence for regionally varying climate trends by presenting a contrasting centennial‐scale variations of oxygen isotope composition (δ18O) of juniper trees from the Indian Himalayan region (present study) and Karakoram. The persistence of contrasting δ18O trends in the two regions over the past millennium indicates that regionally contrasting climate trends are a natural phenomenon. Regionally distinct hydroclimatic trends revealed here can explain the anomalous glacier mass balance trends in the Karakoram region and hence the “Karakoram anomaly.”

Density Anomalies in Subsurface Layers of Mars: Model Estimates for the Site of the InSight Mission Seismometer

A model distribution of anomalous masses in the southwestern part of Elysium Planitia under the surface of the site of the InSight mission seismometer has been obtained. Numerical simulations are performed with the S-approximation method by expansions of the data on the Martian topography and gravitational field (the MRO120D model) in spherical harmonics to the 90th degree and order. Inhomogeneity of the density structure in the form of zones, containing blocks of higher and lower density in the subsurface layers of the study area, has been revealed.

Extraction of artefactual MRS patterns from a large database using non-negative matrix factorization.

Despite the success of automated pattern recognition methods in problems of human brain tumor diagnostic classification, limited attention has been paid to the issue of automated data quality assessment in the field of MRS for neuro-oncology. Beyond some early attempts to address this issue, the current standard in practice is MRS quality control through human (expert-based) assessment. One aspect of automatic quality control is the problem of detecting artefacts in MRS data. Artefacts, whose variety has already been reviewed in some detail and some of which may even escape human quality control, have a negative influence in pattern recognition methods attempting to assist tumor characterization. The automatic detection of MRS artefacts should be beneficial for radiology as it guarantees more reliable tumor characterizations, as well as the development of more robust pattern recognition-based tumor classifiers and more trustable MRS data processing and analysis pipelines. Feature extraction methods have previously been used to help distinguishing between good and bad quality spectra to apply subsequent supervised pattern recognition techniques. In this study, we apply feature extraction differently and use a variant of a method for blind source separation, namely Convex Non-Negative Matrix Factorization, to unveil MRS signal sources in a completely unsupervised way. We hypothesize that, while most sources will correspond to the different tumor patterns, some of them will reflect signal artefacts. The experimental work reported in this paper, analyzing a combined short and long echo time 1 H-MRS database of more than 2000 spectra acquired at 1.5T and corresponding to different tumor types and other anomalous masses, provides a first proof of concept that points to the possible validity of this approach.

Polynomial-based density inversion of gravity anomalies for concealed iron-deposit exploration in North China

Inversion of residual gravity anomalies is an important geophysical technique for depicting subsurface density contrasts, for example, for mineral deposits. We have expressed subsurface density variations using depth-variable polynomial functions and developed the polynomial coefficient inversion (PCI) method, which is an alternative method for mapping subsurface density distributions by inverting the coefficients of density-contrast functions. PCI enables the linear inversion of density variations without vertically subdividing the subsurface. Synthetic tests indicate that PCI combines polynomial functions and multiple constraints to highlight the anomalous masses through an iterative process with appropriate weighting parameters. We apply our method to a local investigation of banded iron formation (BIF) deposits in the Hebei Province, North China. The inversion results depict the approximate distribution of the subsurface density contrasts to identify the stratigraphic boundaries of different lithologies and BIF-favorable zones, thus implying that local iron-rich ore bodies may be located at the syncline axis or dip along the faults. The successful application of PCI for the BIF deposits indicates that this method is a promising strategy for density mapping.

Kantorovich-Rubinstein misfit for inverting gravity-gradient data by the level-set method

We have developed a novel Kantorovich-Rubinstein (KR) norm-based misfit function to measure the mismatch between gravity-gradient data for the inverse gradiometry problem. Under the assumption that an anomalous mass body has an unknown compact support with a prescribed constant value of density contrast, we implicitly parameterize the unknown mass body by a level-set function. Because the geometry of an underlying anomalous mass body may experience various changes during inversion in terms of level-set evolution, the classic least-squares ([Formula: see text]-norm-based) and the [Formula: see text]-norm-based misfit functions for governing the level-set evolution may potentially induce local minima if an initial guess of the level-set function is far from that of the target model. The KR norm from the optimal transport theory computes the data misfit by comparing the modeled data and the measured data in a global manner, leading to better resolution of the differences between the inverted model and the target model. Combining the KR norm with the level-set method yields a new effective methodology that is not only able to mitigate local minima but is also robust against random noise for the inverse gradiometry problem. Numerical experiments further demonstrate that the new KR norm-based misfit function is able to recover deep dipping flanks of SEG/EAGE salt models even at extremely low signal-to-noise ratios. The new methodology can be readily applied to gravity and magnetic data as well.

Pseudo-nitzschia bloom dynamics in the Gulf of Maine: 2012–2016

The toxic diatom genus Pseudo-nitzschia is a growing presence in the Gulf of Maine (GOM), where regionally unprecedented levels of domoic acid (DA) in 2016 led to the first Amnesic Shellfish Poisoning closures in the region. However, factors driving GOM Pseudo-nitzschia dynamics, DA concentrations, and the 2016 event are unclear. Water samples were collected at the surface and at depth in offshore transects in summer 2012, 2014, and 2015, and fall 2016, and a weekly time series of surface water samples was collected in 2013. Temperature and salinity data were obtained from NERACOOS buoys and measurements during sample collection. Samples were processed for particulate DA (pDA), dissolved nutrients (nitrate, ammonium, silicic acid, and phosphate), and cellular abundance. Species composition was estimated via Automated Ribosomal Intergenic Spacer Analysis (ARISA), a semi-quantitative DNA finger-printing tool. Pseudo-nitzschia biogeography was consistent in the years 2012, 2014, and 2015, with greater Pseudo-nitzschia cell abundance and P. plurisecta dominance in low-salinity inshore samples, and lower Pseudo-nitzschia cell abundance and P. delicatissima and P. seriata dominance in high-salinity offshore samples. During the 2016 event, pDA concentrations were an order of magnitude higher than in previous years, and inshore-offshore contrasts in biogeography were weak, with P. australis present in every sample. Patterns in temporal and spatial variability confirm that pDA increases with the abundance and the cellular DA of Pseudo-nitzschia species, but was not correlated with any one environmental factor. The greater pDA in 2016 was caused by P. australis – the observation of which is unprecedented in the region – and may have been exacerbated by low residual silicic acid. The novel presence of P. australis may be due to local growth conditions, the introduction of a population with an anomalous water mass, or both factors. A definitive cause of the 2016 bloom remains unknown, and continued DA monitoring in the GOM is warranted.

D mesons as a probe of Casimir effect for chiral symmetry breaking

We propose $D$ mesons as probes to investigate finite-volume effects for chiral symmetry breaking at zero and finite temperature. By using the $2+1$-flavor linear-sigma model with constituent light quarks, we analyze the Casimir effects for the $\sigma$ mean fields: The chiral symmetry is rapidly restored by the antiperiodic boundary for light quarks, and the chiral symmetry breaking is catalyzed by the periodic boundary. We also show the phase diagram of the $\sigma$ mean fields on the volume and temperature plane. For $D$ mesons, we employ an effective model based on the chiral-partner structure, where the volume dependence of $D$ mesons is induced by the $\sigma$ mean fields. We find that $D_s$ mesons are less sensitive to finite volume than $D$ mesons, which is caused by the insensitivity of $\sigma_s$ mean fields. An anomalous mass shift of $D$ mesons at high temperature with the periodic boundary will be useful in examinations with lattice QCD simulations. The dependence on the number of compactified spatial dimensions is also studied.

Understanding the variation of stratosphere–troposphere coupling during stratospheric northern annular mode events from a mass circulation perspective

We revisit the various stratosphere–troposphere coupling relation from the perspective of the meridional mass circulation. We constructed 10-hPa northern annular mode (NAM) phase composites to show the typical spatiotemporal evolution of circulation anomalies during the NAM’s life cycle. Our results indicate that there is large case-to-case difference in the temporal evolution and vertical profile of polar temperature anomalies during NAM events, which shows no strong dependence on the intensity and duration of NAM events, but agrees well with the variations of the three branches of mass circulation at 60°N: the stratospheric poleward warm air branch (ST), the poleward warm air branch in the upper troposphere (WB), and the equatorward cold air branch in the lower troposphere (CB). Such correspondence is due to the dynamic heating and cooling anomalies associated with the redistribution of air masses by the anomalous meridional mass circulation in different isentropic layers. The various relationship among the three mass circulation branches is attributed to anomalous wave activities. The amplitude and westward tilt of waves are always stronger (weaker) throughout the stratosphere before (after) the peak time of negative NAM events, leading to a stronger (weaker) ST before (after) the peak time. Variations in WB and CB are mostly dependent on wave variabilities in the mid- to lower troposphere, leading to variations in the timing of in- or out-of-phase coupling of the ST with the WB and CB, and thus various thermostructure during NAM events. At a later stage of the negative NAM events when the polar temperature becomes colder and the polar jet recovers, the weakened baroclinic instability in the lower stratosphere provides favorable conditions for the strengthening of the WB and CB if wave activities strengthen in the troposphere during that period.

η′ and η mesons at high T when the UA(1) and chiral symmetry breaking are tied

The approach to the eta'-eta complex employing chirally well-behaved quark-antiquark bound states and incorporating the non-Abelian axial anomaly of QCD through the generalization of the Witten-Veneziano relation, is extended to finite temperatures. Employing the chiral condensate has led to a sharp chiral and U_A(1) symmetry restoration, but with the condensates of quarks with realistic explicit chiral symmetry breaking, which exhibit a smooth, crossover chiral symmetry restoration in qualitative agreement with lattice QCD results, we get a crossover U_A(1) transition, with smooth and gradual melting of anomalous mass contributions. This way we obtain a substantial drop of the eta' mass around the chiral transition temperature, but no eta mass drop. This is consistent with the present empirical evidence.

An Alternative Model of Rotation Curve that Explains Anomalous Orbital Velocity, Mass Discrepancy and Structure of Some Galaxies

A new model of galaxy rotation based on the cyclostrophic model of vortices found in nature is developed. The model is tested using the SPARC dataset of 175 galaxies and a smaller dataset comprising of 60 galaxies. Analysis of the datasets showed that galactic rotation can be adequately described using the observed surface brightness of galaxies and the newly developed cyclostrophic velocity model. The use of the luminosity and the inverse mass-to-light ratio in lieu of the surface brightness, also yield a very good fit of the observed and computed galaxy rotation velocity. Evidently, galactic rotation greatly depends on the cyclostrophic balance of the pressure gradient and the centrifugal forces and the seismic-induced radial expansion occurring in various stars. This is the most probable origin of the action of a single force law that has been overlooked in previous studies. Therefore, the need for a super-massive black hole at the center of galaxies or hidden dark matter can be eliminated. Attractive gravitational force can occur even without a massive black hole at the center of galaxies. There appears to be a pressure gradient force between the center and the outer parts of galaxies that sustains attraction. The cyclostrophic model appears to be the physical basis of the Tully-Fisher relation. Furthermore, the missing mass problem associated with galactic rotation can be attributed to the orbital expansion of celestial objects perturbed by seismic-induced forces. In addition, massive tremors or starquakes may create a domino effect in perturbing nearby stars along the axis of the seismic-induced force and this could result in the formation of elliptical galaxies as the orbits of seismic-perturbed neighboring stars become larger.

An Analytical Flow Model for Heterogeneous Multi-Fractured Systems in Shale Gas Reservoirs

The use of multiple hydraulically fractured horizontal wells has been proven to be an efficient and effective way to enable shale gas production. Meanwhile, analytical models represent a rapid evaluation method that has been developed to investigate the pressure-transient behaviors in shale gas reservoirs. Furthermore, fractal-anomalous diffusion, which describes a sub-diffusion process by a non-linear relationship with time and cannot be represented by Darcy’s law, has been noticed in heterogeneous porous media. In order to describe the pressure-transient behaviors in shale gas reservoirs more accurately, an improved analytical model based on the fractal-anomalous diffusion is established. Various diffusions in the shale matrix, pressure-dependent permeability, fractal geometry features, and anomalous diffusion in the stimulated reservoir volume region are considered. Type curves of pressure and pressure derivatives are plotted, and the effects of anomalous diffusion and mass fractal dimension are investigated in a sensitivity analysis. The impact of anomalous diffusion is recognized as two opposite aspects in the early linear flow regime and after that period, when it changes from 1 to 0.75. The smaller mass fractal dimension, which changes from 2 to 1.8, results in more pressure and a drop in the pressure derivative.