Potential Limitations Research Articles

Black currant cultivars, developed at the Polli Horticultural Research Center (Estonia), in Northwest Russia

Background. Introduction of new foreign cultivars makes it possible to expand the limits of the genetic potential of the VIR collection. A comprehensive study of such germplasm accessions is important for identifying sources of traits useful for breeding and the best cultivars for practical utilization. Materials and methods. Eight black currant cultivars released in Estonia were studied from 2015 through 2023 at Pushkin and Pavlovsk Laboratories of VIR. Conventional methods were used to test their adaptability and assess their main productivity indicators and berry quality. The resulting data were statistically processed in Microsoft Excel according to the guidelines by B. A. Dospekhov. Results and conclusion. The studied cultivars appeared well adapted to the environments of Northwest Russia. The heat supply in Leningrad Province is optimal for their cultivation. Good adaptability, synchronized fruit ripening, stable yields, and fine taste of berries were demonstrated by cvs. ‘Almo’ (k-44169), ‘Albos’ (k-44167), ‘Elo’ (k-44171), ‘Karri’ (k-44172), ‘Mulgi Must’ (k-38061), ‘Musti’ (k-44173), and ‘Varmas’ (k-44174). They are recommended for amateur gardens in Northwest Russia. Cv. ‘Karri’ (k-44172) is a promising source of such traits as good self-fertility, large fruit size, stable yield, well-balanced taste, high anthocyanin content in berries, and resistance to American powdery mildew and gall mite. Cv. ‘Varmas’ is a source of earliness, high self-fertility, and dessert taste of berries.

Assessment of Free Energy Functions for Sand

ABSTRACTThe advantages of constitutive models in energy‐conservation frameworks have been widely addressed in the literature. A key component is choosing an appropriate energy potential to derive the hyperelastic constitutive equations. This article investigates the advantages and limitations of different energy potentials found in the literature based on mathematical conditions to guarantee numerical stability, such as the desired order of homogeneity, positive and non‐singular stiffness within the application range, and equivalent Poisson's ratio from a constitutive modelling standpoint. Potentials meeting the aforementioned criteria are employed to simulate the response envelopes of Karlsruhe fine sand (KFS). Moreover, the performance of the potentials, in conjunction with plasticity theories, is examined. To achieve this, the hyperelastic constitutive equations have been coupled with the bounding surface plasticity model of Dafalias and Manzari to reproduce the soil response in a hyperelastic–plastic frame. Finally, one of the potentials is modified, whereas recommendations for incorporating other appropriate free energy functions into different soil constitutive models are presented. Furthermore, 100 closed elastic strain cycles have been simulated with the bounding surface plasticity model of Dafalias and Manzari considering the original hypoelastic stiffness and hyperelastic–plastic constitutive equations. Using the hypoelastic framework in the simulation led to stress accumulation after 100 closed elastic strain loops, while a reversible response was predicted using the hyperelastic stiffness tensor.

Stability and dissolution of single-crystalline iron oxide thin films in electrochemical environments

The stability of single-crystalline monolayer FeO(111) and 10 nm thin Fe3O4(111) films on Pt(111) upon exposure to environments of increasing chemical complexity has been studied with X-ray photoelectron spectroscopy, temperature-programmed desorption, in-situ scanning tunneling microscopy, and cyclic voltammetry. The well-defined oxide films, which were prepared under ultrahigh-vacuum conditions, were exposed to aqueous solutions of different pH and electrochemical cycling in pure and catechol-containing electrolyte. The films are stable in neutral (pH 7) and alkaline (pH 13) solutions both at open circuit conditions and during electrochemical cycling within the limits of hydrogen and oxygen evolution potentials. Also in strongly acidic (pH 1) perchlorate solution the films remain intact under open circuit conditions, but they quickly dissolve on application of electrochemical potential. Especially for the ultrathin FeO(111) films, catechol enhances the dissolution at neutral pH during electrochemical cycling. A comparison of Pt(111), FeO(111) and Fe3O4(111) substrates in the electrochemical catechol oxidation reaction reveals enhanced and sustained activity of FeO in alkaline environment, while strong deactivation occurs on Pt(111) and Fe3O4(111). This is explained by the weaker interaction between catechol and FeO(111) compared to the other substrates, which hampers the formation of a barrier layer on the electrode surface.

Deterministic 3-server on a circle and the limitation of canonical potentials

The deterministic k-server conjecture states that there is a k-competitive deterministic algorithm for the k-server problem for any metric space. We show that the work function algorithm is 3-competitive for the 3-server problem on circle metrics, a case left open by Coester and Koutsoupias (2021). Our analysis follows the existing framework but introduces a new potential function which may be viewed as a relaxation of the counterpart by Coester and Koutsoupias (2021). We further notice that the new potential function and many existing ones can be rewritten in a canonical form. Through a computer-aided verification, however, we find that no such canonical potential function can resolve the deterministic 3-server conjecture for general metric spaces under the current analysis framework.

Weak solutions of anisotropic (and crystalline) inverse mean curvature flow as limits of p-capacitary potentials

We construct weak solutions of the anisotropic inverse mean curvature flow (A-IMCF) under very mild assumptions both on the anisotropy (which is simply a norm in RN with no ellipticity nor smoothness requirements, in order to include the crystalline case) and on the initial data. By means of an approximation procedure introduced by Moser, our solutions are limits of anisotropic p-harmonic functions or p-capacitary functions (after a change of variable), and we get uniqueness both for the approximating solutions (i.e., uniqueness of p-capacitary functions) and the limiting ones. Our notion of weak solution still recovers variational and geometric definitions similar to those introduced by Huisken-Ilmanen, but requires to work within the broader setting of BV-functions. Despite of this, we still reach classical results like the continuity and exponential growth of perimeter, as well as outward minimizing properties of the sublevel sets. Moreover, by assuming the extra regularity given by an interior rolling ball condition (where a sliding Wulff shape plays the role of a ball), the solutions are shown to be continuous and satisfy Harnack inequalities. Finally, examples of explicit solutions are built.

(Invited) Fundamentals of Single Atom Alloy Catalysts for Electrochemical Nitrate Reduction to Ammonia

Electrochemical conversion of toxic nitrate into useful ammonia provides a route to remediating the most frequent water pollutant while simultaneously generating one of the most produced bulk chemicals. While highly desirable, this conversion is plagued by complications including a highly branching reaction pathway - which can produce highly toxic undesirable products, the need to reduce a negatively charged species, a relatively low nitrate concentration, and competition for electrons between nitrate reduction and parasitic hydrogen evolution. Therefore, electrocatalysts must be developed which are highly selective not only for nitrate over other species in the water matrix, but also selective to the desired ammonia product. Single atom alloy catalysts, where a single atom of one element is embedded in a solvating phase of a secondary element, provides an opportunity to engineer catalysts with atomic level precision. In this presentation, we will outline the fundamental behavior of single atom alloy for nitrate reduction. We explore this topic through density functional theory calculations of the reaction mechanisms, including thermodynamics and kinetic aspects. Particularly, we will discuss the effect of single atom identity, effect of matrix element, and pH and potential. We show that the ability of the single atom to localize the N* species drives the reduction towards ammonia formation, as exemplified by Ru in Cu, while facile exchange of N* between the single atom site and the matrix leads to the formation of N2 or other undesirable products, as exemplified by Pd in Cu and Au in Cu, respectively. We also discuss the importance of the selection of the solvating element; for example, Cu is a good solvating metal because it is a good conductor, while minimizing the hydrogen evolution reaction. Further, we discuss the limits of pH and potential on the performance. In general, higher pH and more moderately negative potentials favor nitrate reduction to NH3 or N2, while lower pH and more negative potentials drive H2 evolution, and generation of NOx species.

Unveiling Optical Nonlinearity: Exploring Nickel‐Curcumin Complexes through Z‐Scan and Degenerate Four Wave Mixing Techniques

AbstractTwo Curcumin (Cur) based mixed ligand complexes of Nickel have been investigated for their optical nonlinearity (NLO). Physicochemical characterization of two nickel precursors and their interaction with curcumin produced two molecules, namely Ni(C3S5)(Cur).2H2O (abbreviated as NiThCur) and NiCl(Cur)(PPh3) (abbreviated as NiTppCur). Additionally the Conceptual‐Density‐Functional‐Theory (CDFT) studies were performed. CDFT‐based optimization parameters of both molecules are theoretically interpreted. HOMO‐LUMO energy gap of NiThCur and NiTppCur were calculated 1.474 eV and 2.744 eV respectively. Both molecules demonstrated good NLO activities, studied by a Z‐scan approach and additionally with a Differential Four wave Mixing (DFWM) technique. Preliminarily investigations showed that the molecules can be potential optical limiters (OL). These studies divulge the exhibition of a 3‐photon absorption (3PA) mechanism by the synthesized molecules. NLO absorption 3PA coefficient (γ) value of 1.34×10−24 m3/W2, third‐order optical susceptibility (χ(3)) value of 1.543×10−11 esu, and the figure of merit 6.64×10−14 esu was observed for the NiThCur complex and γ=3.61×10−24 m3/W2, χ(3)=1.521×10−11 esu, and FoM=5.61×10−14 esu for NiTppCur with Z‐scan (γ and χ(3)) and DFWM methods, respectively. Normalized transmittance (NT) exhibited a decrease to 78.5 % from 100 % in NiThCur and to 69.5 % in NiTppCur. Optical limiting calculations are also presented.

Deciphering diffuse scattering with machine learning and the equivariant foundation model: the case of molten FeO

Bridging the gap between diffuse x-ray or neutron scattering measurements and predicted structures derived from atom–atom pair potentials in disordered materials, has been a longstanding challenge in condensed matter physics. This perspective gives a brief overview of the traditional approaches employed over the past several decades. Namely, the use of approximate interatomic pair potentials that relate three-dimensional structural models to the measured structure factor and its’ associated pair distribution function. The use of machine learned interatomic potentials has grown in the past few years, and has been particularly successful in the cases of ionic and oxide systems. Recent advances in large scale sampling, along with a direct integration of scattering measurements into the model development, has provided improved agreement between experiments and large-scale models calculated with quantum mechanical accuracy. However, details of local polyhedral bonding and connectivity in meta-stable disordered systems still require improvement. Here we leverage MACE-MP-0; a newly introduced equivariant foundation model and validate the results against high-quality experimental scattering data for the case of molten iron(II) oxide (FeO). These preliminary results suggest that the emerging foundation model has the potential to surpass the traditional limitations of classical interatomic potentials.

Soliton gas: Theory, numerics, and experiments.

The concept of soliton gas was introduced in 1971 by Zakharov as an infinite collection of weakly interacting solitons in the framework of Korteweg-de Vries (KdV) equation. In this theoretical construction of a diluted (rarefied) soliton gas, solitons with random amplitude and phase parameters are almost nonoverlapping. More recently, the concept has been extended to dense gases in which solitons strongly and continuously interact. The notion of soliton gas is inherently associated with integrable wave systems described by nonlinear partial differential equationslike the KdV equationor the one-dimensional nonlinear Schrödinger equationthat can be solved using the inverse scattering transform. Over the last few years, the field of soliton gases has received a rapidly growing interest from both the theoretical and experimental points of view. In particular, it has been realized that the soliton gas dynamics underlies some fundamental nonlinear wave phenomena such as spontaneous modulation instability and the formation of rogue waves. The recently discovered deep connections of soliton gas theory with generalized hydrodynamics have broadened the field and opened new fundamental questions related to the soliton gas statistics and thermodynamics. We review the main recent theoretical and experimental results in the field of soliton gas. The key conceptual tools of the field, such as the inverse scattering transform, the thermodynamic limit of finite-gap potentials, and generalized Gibbs ensembles are introduced and various open questions and future challenges are discussed.

The diffusive limit of Boltzmann equation in torus

The Boltzmann equation of kinetic theory gives a statistical description of a gas of interacting particles. It is well known that the Boltzmann equation is related to the Euler and Navier–Stokes equations in the field of gas dynamics. In this paper we are concerned with the incompressible Navier–Stokes–Fourier limit of the Boltzmann equation. We prove the incompressible Navier–Stokes–Fourier limit globally in time and the time decay rate of the solution to the rescaled Boltzmann equation in a torus. For ɛ small, by using the truncated expansion and Lx,v2 – Lx,v∞ method, we prove such a limit for the general potentials γ∈(−3,1] .

S-matrix positivity without Lorentz invariance: a case study

We investigate the analytic structure of scattering amplitudes in theories in which Lorentz invariance is spontaneously broken. We do so by computing and studying the S-matrix for a simple example: a superfluid described by a complex scalar with quartic interactions. The computation is confined to tree-level, for there are no absolutely stable single-particle states, though the lifetime can be made long by lowering the chemical potential. For the 2 → 2 amplitude in center-of-mass configurations, not only is crossing symmetry violated, there appears a tree level branch cut for unphysical kinematics. Its appearance is a consequence of non-analyticity in the dispersion relation. The branch point defines a new scale in the problem, which scales inversely with the chemical potential. In this example, even derivatives of the forward amplitude are positive while odd derivatives are negative. This pattern can be understood in a general way in the limit of a small chemical potential, or weak Lorentz breaking.

Novel third order nonlinear optical stilbazolium crystal replaced with 3-methoxy benzaldehyde as donor for optical device applications

A novel organic nonlinear optical stilbazolium group single crystal of 1-methyl-2-[2-(3-methoxystyryl)]-pyridinium iodide (subsequently referred to as MSMI) was grown by the solution growth technique using the method of slow evaporation at ambient temperature. The Single-crystal XRD investigation indicates that the MSMI crystal belongs to a monoclinic crystal system with a centrosymmetric space group. CHN elemental analyser confirms the weight percentage of carbon (C = 51.00 %) hydrogen (H = 4.55 %) and nitrogen (N = 3.94 %) in the MSMI crystal structure. The presence of 16 hydrogen atoms and 15 carbon atoms in the MSMI was affirmed by the Nuclear Magnetic Resonance (NMR) spectroscopic analysis. Fourier Transform Infrared (FTIR) studies confirmed the fundamental vibrations for different functional groups found in the MSMI crystal. The Hirsfeld surface analysis figured out the hydrogen bond interaction and π…π interaction which supports the stability of the crystal structure. The crystal is found to exhibit transmittance of wavelength above 400 nm and has a band gap of 3.05 eV ascertained from UV–Vis-NIR spectroscopic analysis. Photoluminescence (PL) studies reveal that the title crystal has an emission wavelength of 572 nm. The surface characteristics of the title crystal were examined by Atomic Force Microscopy (AFM), and etching studies. The value of Meyer's number is n = 1.8 which is determined by the Vickers microhardness studies. The value of the third-order nonlinear refractive index (n2) is 4.662×10−8 cm2/W, the nonlinear absorption coefficient (β) is 1.305×10−3 cm/W, nonlinear susceptibility (χ(3)) is 9.297×10−5 esu and the optical limiting threshold is 11.43 J/cm2 was ascertained form the Z-scan technique. The results indicate that the MSMI crystal is a potential optical limiter and has promising applications in nonlinear optical devices.

Efficient data management in Internet of Things: A survey of data aggregation techniques

The Internet of Things (IoT) refers to a vast network of interconnected devices, objects, and systems powered by sensors, software, and connectivity capabilities. The interconnectivity of IoT devices has led to a substantial increase in data production. Efficiently managing and analyzing large data volumes is a significant challenge for IoT systems. To address this challenge, data aggregation is the primary process. IoT data aggregation aims to provide high-quality service by ensuring fast data transmission, high reliability, minimal energy consumption, and data priority consideration. Data aggregation involves collecting data from multiple sensors and devices and then integrating it using a function to minimize system traffic. This paper thoroughly examines data aggregation techniques in the IoT context. Techniques are grouped according to underlying principles, and their potential applications, advantages, and limitations are discussed.

The Perspective of Unani Medicine in Understanding Melasma – A Review

Abstract: Melasma, a prevalent hyperpigmentation skin disorder, poses significant challenges in dermatology clinics. Despite its global impact, conventional treatment options often entail potential side effects and limitations, necessitating the search for alternative therapeutic strategies. : This narrative review aims to advance the understanding of melasma from the perspective of Unani medicine, an ancient healing system recognized by the World Health Organization. It seeks to explore potential therapeutic avenues within the Unani medical paradigm by synergizing ancient wisdom with contemporary perspectives. : The review delves into the Unani scholars' understanding of melasma, known as Kalaf, drawing from the wisdom of renowned scholars. Their insights into the multifactorial etiology of melasma, including pathogenesis, treatment approach, and recommended prescriptions, are discussed. : The descriptions of melasma by Unani scholars have documented the etiopathogenesis, risk factors, and management in detail and emphasize personalized interventions based on the pathological concepts of Unani medicine. Moreover, some of these interventions were also investigated in recent clinical trials and found to have comparable efficacy with standard treatment options. : This review fosters the understanding of the pathogenesis of melasma according to Unani concepts and a holistic approach to the management of melasma, drawing from the timeless legacy of the Unani system of medicine. This review may serve as a reference point for future research, enabling the planning of subsequent studies on this disease with a comprehensive understanding of the previous investigations conducted in this field.

An ancient bacterial zinc acquisition system identified from a cyanobacterial exoproteome.

Bacteria have developed fine-tuned responses to cope with potential zinc limitation. The Zur protein is a key player in coordinating this response in most species. Comparative proteomics conducted on the cyanobacterium Anabaena highlighted the more abundant proteins in a zur mutant compared to the wild type. Experimental evidence showed that the exoprotein ZepA mediates zinc uptake. Genomic context of the zepA gene and protein structure prediction provided additional insights on the regulation and putative function of ZepA homologs. Phylogenetic analysis suggests that ZepA represents a primordial system for zinc acquisition that has been conserved for billions of years in a handful of species from distant bacterial lineages. Furthermore, these results show that Zur may have been one of the first regulators of the FUR family to evolve, consistent with the scarcity of zinc in the ecosystems of the Archean eon.

Probiotics Benefits, Potential Limitations and Risks

Probiotics Benefits, Potential Limitations and Risks

Can mental health practice benefit from procedural justice theory? A critical analysis on the opportunities and pitfalls of procedural justice to address coercion and human rights issues in psychiatry

The theory of procedural justice, derived from social psychology, is employed in numerous fields of study concerned with the quality of interactions involving individuals in positions of authority. Although this theory is increasingly cited for its potential to promote approaches aimed at mitigating the effects of psychiatric coercion and better respecting individuals' rights, empirical literature provides limited insights into how procedural justice could be translated into practice. It is important, therefore, to examine the theoretical and practical implications of such an orientation. Based on a critical analysis of existing literature, this article will discuss the potential contributions and limitations of procedural justice applied in the field of mental health and psychiatric nursing. Procedural justice has limitations regarding solutions for human rights violations in psychiatry. It nonetheless allows a focus on the quality of interactions with individuals in coercive contexts, in addition to considering the social and identity-related implications of psychiatric coercion.

Cell-free DNA from nail clippings as source of normal control for genomic studies in hematologic malignancies.

Comprehensive genomic sequencing is becoming a critical component in the assessment of hematologic malignancies, with broad implications for patients' management. In this context, unequivocally discriminating somatic from germline events is challenging but greatly facilitated by matched analysis of tumor:normal pairs of samples. In contrast to solid tumors, in hematologic malignancies conventional sources of normal control material (peripheral blood, buccal swabs, saliva) could be highly involved by the neoplastic process, rendering them unsuitable. In this work we describe our real-world experience using cell-free DNA (cfDNA) isolated from nail clippings as an alternate source of normal control material, through the dedicated review of 2,610 tumor:nail pairs comprehensively sequenced by MSK-IMPACT-heme. Overall, we found that nail cfDNA is a robust germline control for paired genomic studies. In a subset of patients, nail DNA may be contaminated by tumor DNA, reflecting unique attributes of the hematologic disease and transplant history. Contamination is generally low level, but significantly more common among patients with myeloid neoplasms (20.5%; 304/1,482) than among those with lymphoid diseases (5.4%; 61/1,128) and particularly enriched in myeloproliferative neoplasms with marked myelofibrosis. When identified in patients with lymphoid and plasma-cell neoplasms, mutations commonly reflected a myeloid profile and correlated with a concurrent/evolving clonal myeloid neoplasm. Donor DNA was identified in 22% (11/50) of nails collected after allogeneic stem-cell transplantation. In this cohort, an association with a recent history of graft-versus-host disease was identified. These findings should be considered as a potential limitation to the use of nails as a source of normal control DNA but could also provide important diagnostic information regarding the disease process.

A recent survey of image-based malware classification using convolution neural network

<p>Despite numerous breakthroughs in creating and applying new and current approaches to malware detection and classification, the number of malware attacks on computer systems and networks is increasing. Malware authors are continually changing their operations and activities with tools or methodologies, making it tough to categorize and detect malware. Malware detection methods such as static or dynamic detection, although useful, have had challenges detecting zero-day malware and polymorphic malware. Even though machine learning techniques have been applied in this area, deep neural network models using image visualization have proven to be very effective in malware detection and classification, presenting better accuracy results. Hence, this article intends to conduct a survey showing recent works by researchers and their techniques used for malware detection and classification using convolutional neural network (CNN) models highlighting strengths, and identifying areas of potential limitations such as size of datasets and features extraction. Furthermore, a review of relevant research publications on the subject is offered, which also highlights the limitations of models and dataset availability, along with a full tabular comparison of their accuracy in malware detection and classification. Consequently, this review study will contribute to the advancement and serve as a basis for future research in the field of developing CNN models for malware detection and classification.</p>

Topological features of functional brain networks and subclinical impulsivity: an investigation in younger and older adults.

Impulsive traits (i.e., the tendency to act without forethought regardless of negative outcomes) are frequently found in healthy populations. When exposed to risk factors, individuals may develop debilitating disorders of impulse control (addiction, substance abuse, gambling) characterized by behavioral and cognitive deficits, eventually leading to huge socioeconomic costs. With the far-reaching aim of preventing the onset of impulsive disorders, it is relevant to investigate the topological organization of functional brain networks associated with impulsivity in sub-clinical populations. Taking advantage of the open-source LEMON dataset, we investigated the topological features of resting-state functional brain networks associated with impulsivity in younger (n=146, age: 20-35) and older (n=61, age: 59-77) individuals, using a graph-theoretical approach. Specifically, we computed indices of segregation and integration at the level of specific circuits and nodes known to be involved in impulsivity (frontal, limbic, and striatal networks). In younger individuals, results revealed that impulsivity was associated with a more widespread, less clustered and less efficient functional organization, at all levels of analyses and in all selected networks. Conversely, impulsivity in older individuals was associated with reduced integration and increased segregation of striatal regions. Speculatively, such alterations of functional brain networks might underlie behavioral and cognitive abnormalities associated with impulsivity, a working hypothesis worth being tested in future research. Lastly, differences between younger and older individuals might reflect the implementation of age-specific adaptive strategies, possibly accounting for observed differences in behavioral manifestations. Potential interpretations, limitations and implications are discussed.