Rate Of Exchange Research Articles

On data minimization and anonymity in pervasive mobile-to-mobile recommender systems

Data minimization is a legal principle that mandates limiting the collection of personal data to a necessary minimum. In this context, we address ourselves to pervasive mobile-to-mobile recommender systems in which users establish ad hoc wireless connections between their mobile computing devices in physical proximity to exchange ratings that represent personal data on which they calculate recommendations. The specific problem is: How can users minimize the collection of ratings over all users while only being able to communicate with a subset of other users in physical proximity? A main difficulty is the mobility of users, which prevents, for instance, the creation and use of an overlay network to coordinate data collection. Users, therefore, have to decide whether to exchange ratings and how many when an ad hoc wireless connection is established. We model the randomness of these connections and apply an algorithm based on distributed gradient descent to solve the distributed data minimization problem at hand. We show that the algorithm robustly produces the least amount of connections and also the least amount of collected ratings compared to an array of baselines. We find that this simultaneously reduces the chances of an attacker relating users to ratings. In this sense, the algorithm also preserves the anonymity of users, yet only of those users who do not establish an ad hoc wireless connection with each other. Users who do establish a connection with each other are trivially not anonymous toward each other. We find that users can further minimize data collection and preserve their anonymity if they aggregate multiple ratings on the same item into a single rating and change their identifiers between connections.

Pinpointing the causal influences of stomatal anatomy and behavior on minimum, operational, and maximum leaf surface conductance.

Leaf surface conductance to water vapor and CO2 across the epidermis (gleaf) strongly determines the rates of gas exchange. Thus, clarifying the drivers of gleaf has important implications for resolving the mechanisms of photosynthetic productivity and leaf and plant responses and tolerance to drought. It is well recognized that gleaf is a function of the conductances of the stomata (gs) and of the epidermis + cuticle (gec). Yet, controversies have arisen around the relative roles of stomatal density (d) and size (s), fractional stomatal opening (α; aperture relative to maximum), and gec in determining gleaf. Resolving the importance of these drivers is critical across the range of leaf surface conductances, from strong stomatal closure under drought (gleaf,min), to typical opening for photosynthesis (gleaf,op), to maximum achievable opening (gleaf,max). We derived equations and analyzed a compiled database of published and measured data for approximately 200 species and genotypes. On average, within and across species, higher gleaf,min was determined 10 times more strongly by α and gec than by d and negligibly by s; higher gleaf,op was determined approximately equally by α (47%) and by stomatal anatomy (45% by d and 8% by s), and negligibly by gec; and higher gleaf,max was determined entirely by d. These findings clarify how diversity in stomatal functioning arises from multiple structural and physiological causes with importance shifting with context. The rising importance of d relative to α, from gleaf,min to gleaf,op, enables even species with low gleaf,min, which can retain leaves through drought, to possess high d and thereby achieve rapid gas exchange in periods of high water availability.

Response of river delta hydrological connectivity to changes in river discharge and atmospheric frontal passage

Atmospheric frontal passage is a common meteorological event that can significantly affect hydrodynamics in coastal environments, including the hydrological connectivity between channels and floodplains that regulates material transport in river deltas. This study is focused on the influence of atmospheric cold fronts on the hydrological connectivity between channels and floodplains within the Wax Lake Delta using the Delft3D FM model. The results demonstrate a substantial effect of passing cold fronts on the exchange of water and transport fraction between the primary channels and floodplains. This impact is intricately connected to the morphodynamical characteristics of the floodplains, the intensity of cold fronts, river discharge, Coriolis force, and tidal currents. The passing cold fronts can enhance or reverse the direction of water exchange between channels and floodplains. For floodplains, the passage of cold fronts can lead to an increase in the rate of water exchange by as much as five times. In the WLD, a substantial fraction of water, 39-58%, is flowing through the floodplains to the bay at the delta front influenced by the prevailing discharge, although there is a significant spatial heterogeneity. Passing cold fronts can alter the transport distribution, depending on the phase of the front. An increase in river discharge tends to bolster floodplain connectivity and lessen the effects of cold fronts. Conversely, decreased river discharge results in reduced connectivity and exacerbates the fluctuations induced by cold fronts. Moreover, the findings indicate that from the apex to downstream, the contribution of channels decreases as they become shallower, while the role of the floodplains increases, leading to a less distinct demarcation between channels and floodplains. It has also been noted that an increase in river discharge correlates with an increased contribution from floodplains to transfer water to the bay.

Regression Models for Calculating State-to-State Coefficients of the Rate of Vibrational Energy Exchanges

Regression Models for Calculating State-to-State Coefficients of the Rate of Vibrational Energy Exchanges

Transient kinetics reveal the mechanism of competitive inhibition of the neutral amino acid transporter ASCT2

ASCT2 (alanine serine cysteine transporter 2), a member of the SLC1 (solute carrier 1) family, mediates Na+-dependent exchange of small neutral amino acids across cell membranes. ASCT2 was shown to be highly expressed in tumor cells, making it a promising target for anti-cancer therapies. In this study, we explored the binding mechanism of the high-affinity competitive inhibitor Lc-BPE with ASCT2, using electrophysiological and rapid kinetic methods. Our investigations reveal that Lc-BPE binding requires one or two Na+ ions initially bound to the apo-transporter with high affinity, with Na1 site occupancy being more critical for inhibitor binding. In contrast to the amino acid substrate bound form, the final, third Na+ ion cannot bind, due to distortion of its binding site (Na2), thus preventing the formation of a translocation-competent complex. Based on the rapid kinetic analysis, the application of Lc-BPE generated outward transient currents, indicating that, despite its net neutral nature, the binding of Lc-BPE in ASCT2 is weakly electrogenic, most likely because of asymmetric charge distribution within the amino acid moiety of the inhibitor. The pre-incubation with Lc-BPE also led to a decrease of the turnover rate of substrate exchange and a delay in the activation of substrate-induced anion current, indicating relatively slow Lc-BPE dissociation kinetics. Overall, our results provide new insight into the mechanism of binding of a prototypical competitive inhibitor to the ASCT transporters.

Heat-induced structural and chemical changes to a computationally designed miniprotein.

The de novo design of miniprotein inhibitors has recently emerged as a new technology to create proteins that bind with high affinity to specific therapeutic targets. Their size, ease of expression, and apparent high stability makes them excellent candidates for a new class of protein drugs. However, beyond circular dichroism melts and hydrogen/deuterium exchange experiments, little is known about their dynamics, especially at the elevated temperatures they seemingly tolerate quite well. To address that and gain insight for future designs, we have focused on identifying unintended and previously overlooked heat-induced structural and chemical changes in a particularly stable model miniprotein, EHEE_rd2_0005. Nuclear magnetic resonance (NMR) studies suggest the presence of dynamics on multiple time and temperature scales. Transiently elevating the temperature results in spontaneous chemical deamidation visible in the NMR spectra, which we validate using both capillary electrophoresis and mass spectrometry (MS) experiments. High temperatures also result in greatly accelerated intrinsic rates of hydrogen exchange and signal loss in NMR heteronuclear single quantum coherence spectra from local unfolding. These losses are in excellent agreement with both room temperature hydrogen exchange experiments and hydrogen bond disruption in replica exchange molecular dynamics simulations. Our analysis reveals important principles for future miniprotein designs and the potential for high stability to result in long-lived alternate conformational states.

The Vega advanced third generation posterior stabilized total knee arthroplasty system enables the restoration of range of motion for high demanding daily activities - A 5-years follow-up study.

The Vega System® PS (Aesculap AG, Tuttlingen, Germany) is an advanced, third generation fixed implant that aims to mimic natural knee kinematics by optimizing pivotal motion while reducing surface stress. This study evaluated mid-term survival and clinical outcomes, including range of motion (ROM) of the modern posterior stabilized implant in order to analyse whether this biomechanically successful implant reaches good results in situ. The first 100 patients to receive the Vega PS System for total knee arthroplasty were invited to take part in this single centre, single surgeon study. Of these, 84 patients were clinically assessed 5-6 years postoperatively. Data which was obtained during this follow-up examination included revision data, range of motion and clinical scores. The 5-year survival rate for exchange of any component was 97.6%, whereby two patients required replacement of the polyethylene gliding surface. Secondary patella resurfacing was performed in 7 patients. Significantly improved results in comparison to the preoperative state could be obtained at the follow-up: KOOS improved from 39.4 to 78.8, SF-12 PCS improved from 32.1 to 42 SF-12 MCS improved from 46 to 53.8 and patella pain improved from 2.7 to 0.3. The mean ROM of the 84 patients after 5 years was 133.1° and mean total KSS was 189.9. This study demonstrates a high survival rate of the Vega PS System® and significant improvements in clinical outcomes 5 years after implantation. The obtained mean ROM indicates that this implant provides good flexibility of the knee joint, allowing a high number of activities. However, due to the rate of secondary patella implantation, routine resurfacing of the patella for all PS TKA cases is highly recommended. The study was registered at clinicaltrials.gov (NCT02802085).

Testing the hypothesis that solvent exchange limits the rates of calcite growth and dissolution.

It is established that the rates of solvent exchange at interfaces correlate with the rates of a number of mineral reactions, including growth, dissolution and ion sorption. To test if solvent exchange is limiting these rates, quasi-elastic neutron scattering (QENS) is used here to benchmark classical molecular dynamics (CMD) simulations of water bound to nanoparticulate calcite. Four distributions of solvent exchanges are found with residence times of 8.9 ps for water bound to calcium sites, 14 ps for that bound to carbonate sites and 16.7 and 85.1 ps for two bound waters in a shared calcium-carbonate conformation. By comparing rates and activation energies, it is found that solvent exchange limits reaction rates neither for growth nor dissolution, likely due to the necessity to form intermediate states during ion sorption. However, solvent exchange forms the ceiling for reaction rates and yields insight into more complex reaction pathways.

Dynamics of energy transport on hydromagnetic Casson slippery nanoflow over curved surface

The study of fluid flow over curved surfaces is crucial in various engineering applications, such as designing aircraft wings, turbines, and submarines. Curved surfaces are being explored in various biomedical applications, such as designing stents for blood vessels and implants for bones and joints. Concerning the present applications of curved stretching sheets on fluid dynamics along with trihybrid nanofluids, this study is unique and fills the research gaps and offers solutions to several issues. This work looks at the flow through the boundary layer of an electrically conductive trihybrid nanofluid and the convection heat exchange of a Casson fluid across a curved stretched surface encircled within a circle of radius R. The study considers the effects of thermal radiation using the non-linearized Rosseland approximation, as well as a magnetic field, and hydromagnetic slip. The flow as well as the transfer of heat problem is mathematically described by curvilinear coordinates. Using the combination of the shooting technique and the Runge-Kutta method, similar solutions to the modeled partial differential equations are produced, and the set of non-linear ordinary differential equations with a boundary value solver is implemented through the MATLAB program. The study finds the influence of several limits on critical characteristics such as fluid velocity, coefficient of skin friction, pressure, temperature, and rate of heat exchange over a surface. The findings are shown in tables and graphs. Additionally, a comparative analysis between the current findings and those found in the literature is provided. Blood-containing nanoparticles (GO-SWCNTs-MWCNTs) on curved surfaces could improve drug delivery effectiveness, growth of synthetic tissues or organs with complex structures and effective cancer therapy treatment.

Moneymate: A Finance Application

Abstract: Moneymate stands as a comprehensive finance application, simplifying personal finance management with ease and precision. It meticulously tracks daily expenditures, offering insightful visuals and categorizes expenses for effortless analysis of spending patterns. Serving as a centralized hub for financial information, it provides real-time updates on assets and currency values relative to the Indian Rupee, aiding informed decisions on investments and transactions. Beyond mere tracking, Moneymate empowers users with tools for goal setting, savings budgeting, and income optimization, fostering a proactive approach to financial planning. Personalized insights and actionable recommendations further enhance its utility in financial decision-making. With a user-friendly design and powerful functionalities, Moneymate transforms the landscape of personal finance management, simplifying tasks such as daily spending, asset management, currency conversion, and income tracking. Its holistic approach makes it an indispensable companion for individuals seeking control and empowerment over their financial health.

TRADE POLICY, EXCHANGE RATE DYNAMICS AND MANUFACTURING SECTOR OUTPUT IN NIGERIA

Two macroeconomic policies that have impacted on Nigerias manufacturing industry are trade and exchange rate policies. From 1981 to 2022, this study looked at the connection between Nigerias real industrial production, exchange rate, and trade policy. Real manufacturing GDP served as a stand-in for real manufacturing output, and explanatory variables similar to the exchange rate, per capita income, monetary policy rate, manufacturing capacity utilization rate, import to export ratio, and dummy variables for structural adjustment were employed. The model was analyzed in the research by means of autoregressive distributed lag (ARDL) technique. The outcomes showed that while exports as a ratio of gross domestic product (EXGDP). Significantly boosted real manufacturing output (RMO) both in the near and distant future times. Imports as a ratio of gross domestic product (IMGDP) had a negative impact on RMO. Trade liberalization by DSAP had a significant benefit on actual manufacturing production over the long run, while it had a minimally positive impact on RMO during the near term. The rate of exchange has a short-term favorable influence on RMO but a long-term negative one. To increase manufacturing output, the federal government of Nigeria should align its trade policy with the export promotion industrialization plan. KEYWORDS: Trade Policy, Exchange Rate Dynamics, Manufacturing Output, ARDL, Nigeria.

Phase composition and numerical model of low-pressure pulse carburized layer in 15Cr14Co12Mo5Ni2W steel

Aerospace engine gear steel, 15Cr14Co12Mo5Ni2W steel, requires carburizing heat treatment to achieve operational performance. However, predicting the carbon concentration during the vacuum carburizing process poses significant challenges. This paper aims to design and establish a predictive model for the carbon concentration during the vacuum carburizing process of 15Cr14Co12Mo5Ni2W steel. Given the complex phase transformations during the vacuum carburizing process caused by the ultra-high alloy content of 15Cr14Co12Mo5Ni2W steel, vacuum short-term intense carburization and diffusion experiments were designed. Characterization methods such as XRD, scanning electron microscopy, electron probe microanalysis, EBSD, and FIB+TEM were used to study the microstructure, phase composition, phase constituents, and distribution of element concentrations during the vacuum carburizing process. Subsequently, a carbon concentration distribution calculation model considering carbide changes during the vacuum carburizing process of 15Cr14Co12Mo5Ni2W steel was established. Boundary conditions for carbon absorption during the intense carburization process of 15Cr14Co12Mo5Ni2W steel were proposed, and the relationship between surface carbon concentration and boundary conditions was determined through experiments. Using the method of forward calculation with least squares fitting of experimental data, the diffusion coefficient of carbon in the austenite of 15Cr14Co12Mo5Ni2W steel and the rate of carbon exchange between carbides and the matrix were derived, providing a more precise predictive tool for optimizing the vacuum carburizing process of 15Cr14Co12Mo5Ni2W steel.

An innovative PCM-modified lining system for energy tunnel: From concept to numerical investigations

The rich geothermal stored in rock mass would result in high temperature to tunnels. This not only makes condition worse to workers, but also wastes geothermal energy and increases cost to adjust the internal environmental temperature. This motivates the present feasibility study on an innovative PCM-modified lining system of conventional energy tunnel, which generally makes use of ground source heat pump (GSHP). That is, the PCM-modified concrete regulates the thermal properties of tunnel linings installed with pipe loops of GSHP. To verify the concept of the new system, a finite element model (FEM) describing it is established, based on a case of high geothermal tunnel. Simulation of the heat conducting process of tunnel linings starting from hydration of cement during cast-in-place concrete, thermal conductivity from surrounding rock mass, circulating of GSHP, phase change within the PCM-modified linings, and boundary effect since ventilation are considered in the modeling. The results demonstrate that the new system would mitigate the level of thermal discomforts during construction stage, and it can improve the stability and efficiency in energy extraction in operation stage. Parametric study on the GSHP with PCM-modified linings gives that the better heat reduction performance can be obtained with the smaller intermittent ratio (IR) of GSHP, smaller temperature range of phase change, and larger latent heat, and higher exchanger rate can be obtained with the larger IR and larger latent heat.

TALICS3: Tape library cloud storage system simulator

High performance computing data is surging fast into the exabyte-scale world, where tape libraries are the main platform for long-term durable data storage besides high-cost DNA. Tape libraries are extremely hard to model, but accurate modeling is critical for system administrators to obtain valid performance estimates for their designs. This research introduces a discrete–event tape simulation platform that realistically models tape library behavior in a networked cloud environment, by incorporating real-world phenomena and effects. The platform addresses several challenges, including precise estimation of data access latency, rates of robot exchange, data collocation, deduplication/compression ratio, and attainment of durability goals through replication or erasure coding. Using the proposed simulator, one can compare the single enterprise configuration with multiple commodity library configurations, making it a useful tool for system administrators and reliability engineers. This makes the simulator a valuable tool for system administrators and reliability engineers, enabling them to acquire practical and dependable performance estimates for their enduring, cost-efficient cold data storage architecture designs.

Evidence for Reductions in Physical and Chemical Plant Defense Traits in Island Flora.

Reduced defense against large herbivores has been suggested to be part of the "island syndrome" in plants. However, empirical evidence for this pattern is mixed. In this paper, we present two studies that compare putative physical and chemical defense traits from plants on the California Channel Islands and nearby mainland based on sampling of both field and common garden plants. In the first study, we focus on five pairs of woody shrubs from three island and three mainland locations and find evidence for increased leaf area, decreased marginal leaf spines, and decreased concentrations of cyanogenic glycosides in island plants. We observed similar increases in leaf area and decreases in defense traits when comparing island and mainland genotypes grown together in botanic gardens, suggesting that trait differences are not solely driven by abiotic differences between island and mainland sites. In the second study, we conducted a common garden experiment with a perennial herb-Stachys bullata (Lamiaceae)-collected from two island and four mainland locations. Compared to their mainland relatives, island genotypes show highly reduced glandular trichomes and a nearly 100-fold reduction in mono- and sesquiterpene compounds from leaf surfaces. Island genotypes also had significantly higher specific leaf area, somewhat lower rates of gas exchange, and greater aboveground biomass than mainland genotypes across two years of study, potentially reflecting a broader shift in growth habit. Together, our results provide evidence for reduced expression of putative defense traits in island plants, though these results may reflect adaptation to both biotic (i.e., the historical absence of large herbivores) and climatic conditions on islands.

Promoting success in thin layer sediment placement: effects of sediment grain size and amendments on salt marsh plant growth and greenhouse gas exchange

Thin layer sediment placement (TLP) is used to build elevation in marshes, counteracting effects of subsidence and sea level rise. However, TLP success may vary due to plant stress associated with reductions in nutrient availability and hydrologic flushing or through the creation of acid sulfate soils. This study examined the influence of sediment grain size and soil amendments on plant growth, soil and porewater characteristics, and greenhouse gas exchange for three key U.S. salt marsh plants: Spartina alterniflora (synonym Sporobolus alterniflorus), Spartina patens (synonym Sporobolus pumilus), and Salicornia pacifica. We found that bioavailable nitrogen concentrations (measured as extractable NH4+‐N) and porewater pH and salinity were inversely related to grain size, while soil redox was more reducing in finer sediments. This suggests that utilizing finer sediments in TLP projects will result in a more reduced environment with higher nutrient availability, while larger grain sized sediments will be better flushed and oxygenated. We further found that grain size had a significant effect on vegetation biomass allocation and rates of gas exchange, although these effects were species‐specific. We found that soil amendments (biochar and compost) did not subsidize plant growth but were associated with increases in soil respiration and methane emissions. Biochar amendments were additionally ineffective in ameliorating acid sulfate conditions. This study uncovers complex interactions between sediment type and vegetation, emphasizing the limitations of soil amendments. The findings aid restoration project managers in making informed decisions regarding sediment type, target vegetation, and soil amendments for successful TLP projects.

Decentralized E-Commerce for Digital Assets

Abstract: In the digital age, the creation and exchange of digital assets have become integral to various domains, including art, music, education, and more. However, the existing centralized marketplaces for these digital assets pose significant challenges, such as high fees, cross-border transaction delays, and limited control for creators and artists. This project introduces a gamechanging solution – a Decentralized E-Commerce platform powered by ERC1155 tokens. The project scope encompasses a comprehensive range of functionalities, including digital asset listing, buying, selling, and secure transaction processing. It aims to create a user-friendly interface that reduces the complexities and costs associated with traditional centralized marketplaces. Moreover, the platform extends its impact across various domains, from music distribution and licensing to educational material sales and NFT marketplaces. It simplifies cross-border e-commerce for digital goods, ensuring secure transactions without the need for currency conversion. The platform's adaptability opens new horizons for creators and entrepreneurs in the digital asset space.

Ligand-induced protein transition state stabilization switches the binding pathway from conformational selection to induced fit

Protein-ligand complex formation is fundamental to biological function. A central question is whether proteins spontaneously adopt binding-competent conformations to which ligands bind conformational selection (CS) or whether ligands induce the binding-competent conformation induced fit (IF). Here, we resolve the CS and IF binding pathways by characterizing protein conformational dynamics over a wide range of ligand concentrations using NMR relaxation dispersion. We determined the relative flux through the two pathways using a four-state binding model that includes both CS and IF. Experiments conducted without ligand show that galectin-3 exchanges between the ground-state conformation and a high-energy conformation similar to the ligand-bound conformation, demonstrating that CS is a plausible pathway. Near-identical crystal structures of the apo and ligand-bound states suggest that the high-energy conformation in solution corresponds to the apo crystal structure. Stepwise additions of the ligand lactose induce progressive changes in the relaxation dispersions that we fit collectively to the four-state model, yielding all microscopic rate constants and binding affinities. The ligand affinity is higher for the bound-like conformation than for the ground state, as expected for CS. Nonetheless, the IF pathway contributes greater than 70% of the total flux even at low ligand concentrations. The higher flux through the IF pathway is explained by considerably higher rates of exchange between the two protein conformations in the ligand-associated state. Thus, the ligand acts to decrease the activation barrier between protein conformations in a manner reciprocal to enzymatic transition-state stabilization of reactions involving ligand transformation.

Ринок електронної комерції в Україні: роль європейських та міжнародних організацій із цифрової комерції

The article examines the role of international and European e-commerce organizations in the context of increasing the competitiveness of e-business in Ukraine. The analysis of trends in the development of the Ukrainian and global e-commerce market was carried out, the importance of the development of international e-commerce and advocacy bodies in accordance with the specified sector was emphasized. The importance of sustainable digital transformation, which will contribute to growth and stimulate sustainable development, was highlighted separately. In this aspect, the need of implementation the legislation, standards and best practices of EU for the harmonization of the digital market of Ukraine as a whole was emphasized. Barriers to the development of e-commerce in Ukraine have been structured, which include: cognitive barriers; language barrier; cultural features; customer support; expansion of consumer rights protection policy in accordance with EU rules; internet connection speed; payment settings/payment services (currency conversion). In addition, the definition of «cross-border electronic commerce» was proposed.

On the simulation and interpretation of substrate-water exchange experiments in photosynthetic water oxidation.

Water oxidation by photosystem II (PSII) sustains most life on Earth, but the molecular mechanism of this unique process remains controversial. The ongoing identification of the binding sites and modes of the two water-derived substrate oxygens ('substrate waters') in the various intermediates (Si states, i = 0, 1, 2, 3, 4) that the water-splitting tetra-manganese calcium penta-oxygen (Mn4CaO5) cluster attains during the reaction cycle provides central information towards resolving the unique chemistry of biological water oxidation. Mass spectrometric measurements of single- and double-labeled dioxygen species after various incubation times of PSII with H218O provide insight into the substrate binding modes and sites via determination of exchange rates. Such experiments have revealed that the two substrate waters exchange with different rates that vary independently with the Si state and are hence referred to as the fast (Wf) and the slow (WS) substrate waters. New insight for the molecular interpretation of these rates arises from our recent finding that in the S2 state, under special experimental conditions, two different rates of WS exchange are observed that appear to correlate with the high spin and low spin conformations of the Mn4CaO5 cluster. Here, we reexamine and unite various proposed methods for extracting and assigning rate constants from this recent data set. The analysis results in a molecular model for substrate-water binding and exchange that reconciles the expected non-exchangeability of the central oxo bridge O5 when located between two Mn(IV) ions with the experimental and theoretical assignment of O5 as WS in all S states. The analysis also excludes other published proposals for explaining the water exchange kinetics.