bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Characterization of Seaweeds From Biri, Northern Samar, Philippines
Authors: Enteria April Ann A. , Abobo Tom Jericho L. , Jr. Abel Alejandro U. Flores, 
Published: August 2024

This research was carried out in an attempt to ascertain the phytochemical screening on selected seaweed species from different barangays in Biri, Northern Samar, Philippines using a descriptive research approach. It also aimed to identify the seaweed species in the study area and determine the three most and least-frequently appearing species respectively, which were subjected to phytochemical screening and the determination of extracts and its physicochemical constituents as conducted from November 2022 to April, 2023. Seaweed samples were collected, identified, and authenticated by an expert. Specimens were preserved in jars containing 10% formaldehyde and seawater in equal volumes. Fresh samples of the three most frequently appearing and the three least frequently appearing species were used for the screening procedures. Results revealed a total of 44 seaweed species present in selected barangays of Biri, Northern Samar. The most-frequently appearing species were Ulva reticulata, Hormophysa cuneiformis, and Turbinaria conoides, while the least-frequently appearing species were Hydropuntia edulis, Laurencia papillosa, and Tricleocarpa fragilis. Chemical characterization of these species confirmed the presence of alkaloids, saponin, phenolic compounds, and anthraquinones, although not all of them contained these metabolites. Lipids and proteins were absent in all species tested. Meanwhile, the ash content of the samples is relatively high, implying that high amounts of minerals may be found in seaweeds. Thus, the researchers recommend the replication of this research in other areas of the province to document seaweed species and their potential applications in the functional food and nutraceutical industries. This will help develop natural products with economic or commercial significance to the residents. Likewise, more specific tests for lipids and proteins in seaweeds may be used in future investigations.
Evaluation of the Interactions of Some Alkali and Alkali Earth Metallic Chlorides on Guaiacol Oxidation by Peroxidase from Watermelon Rind
Authors: O.M Iniaghe, , A.A Ohilebo 
Published: August 2024

Aim: This study evaluated Interactions of some alkali and alkali earth metallic chlorides on guaiacol oxidation by peroxidase from watermelon rind.
Study Design: In vitro enzyme assay.
Place and Duration of Study: Department of Biochemistry, Faculty of Life Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria between September 2023 to November 2023.
Methodology: The kinetics of the oxidation of Guaiacol by the crude peroxidase from the rind of watermelon in the presence of varying concentrations of the chloride salts of Na, K, Mg and Ca was determined spectrophotometrically by monitoring the oxidation of Guaiacol to produce a brown tetraguaiacol monitored at a wavelength of 470nm. The various salt concentrations were varied between 0.5 mM and 3 mM. Each of the reaction mixtures used in the kinetic study comprised; 2.3 mL of 0.6 M sodium acetate buffer (pH 5.4), 0.2 mL of 0.02 mM Guaiacol, 0.1 mL of crude extract, 0.2 mL of varying concentration chloride salt, 0.2 mL of 2 mM of H2O2 added last to start the reaction. The final concentration of H2O2 in the 3 mL assay was 0.13 mM. The total volume of the reaction mixture was 3 mL. The absorbance was read every 2 seconds for one minute after adding hydrogen peroxide using a stop-clock. The control had no metal ion but replaced with distilled water
Results: Results showed that within a salt concentration range of 0.5mM to 3Mm, chlorides of Na, K and Mg activated the peroxidase from the rind of watermelon while CaCl2 reduced the activity in a concentration dependent manner. The optimal salt concentration of these cation activators was 0.5 mM.
Conclusion: These findings are of great importance to industries in understanding the mechanism of action of peroxidase from the rind of watermelon, especially as the search for cheap and alternative sources of peroxidases continues.
Determination of Phytochemical Compositions of Leaves and Flowers of Cassia auriculate
Authors: Parani K. 
Published: August 2024

The present study reveals the morphological characteristics, organoleptic and fluorescence analysis by using various chemicals and reagents to examine the presence of phytochemicals visually in powdered samples of leaves and flowers of Cassia auriculata. The qualitative analysis represents the presence of various phytochemicals viz., steroids, reducing sugars, sugars, alkaloids, phenols, flavonoids, saponins, tannins, Anthraquinones and amino acids in crude extracts (aqueous, ethanol and petroleum ether) of leaves and flowers of Cassia auriculata. The presence of minerals i.e., potassium, phosphorous, sulphur, calcium, were observed in leaves and flowers of Cassia auriculata by qualitatively. Quantitative analysis revealed maximum amount of flavonoids in flowers of Cassia auriculata and lesser amounts of alkaloids were recorded in leaves and flowers of Cassia respectively.
Estimates of ocean wave heights and attenuation in sea ice using the SAR wave mode on Sentinel‐1A
Authors: Ardhuin Fabrice , Collard Fabrice , Chapron Bertrand , Girard‐Ardhuin Fanny , Guitton Gilles , Mouche Alexis , Stopa Justin E. 
Published: March 2015

AbstractSwell evolution from the open ocean into sea ice is poorly understood, in particular the amplitude attenuation expected from scattering and dissipation. New synthetic aperture radar (SAR) data from Sentinel‐1A wave mode reveal intriguing patterns of bright oscillating lines shaped like instant noodles. We investigate cases in which the oscillations are in the azimuth direction, around a straight line in the range direction. This observation is interpreted as the distortion by the SAR processing of crests from a first swell, due to the presence of a second swell. Since deviations from a straight line should be proportional to the orbital velocity toward the satellite, swell height can be estimated, from 1.5 to 5 m in the present case. The evolution of this 13 s period swell across the ice pack is consistent with an exponential attenuation on a length scale of 200 km.
Using dynamical downscaling to examine mechanisms contributing to the intensification of Central U.S. heavy rainfall events
Authors: Harding Keith J. , Snyder Peter K. 
Published: March 2015

AbstractThe frequency and intensity of heavy rainfall events have increased in the Central U.S. over the last several decades, and model projections from dynamical downscaling suggest a continuation with climate change. In this study, we examine how climate change might affect mechanisms related to the development of heavy rainfall events that occur on the scale of mesoscale convective systems over the Central U.S. To accomplish these goals, we incorporate dynamical downscaled simulations of two Coupled Model Intercomparison Project phase 5 models in the Weather Research and Forecasting model that accurately simulate heavy rainfall events. For each model, a set of heavy rainfall events that match the frequency, timing, and intensity of observed events are objectively identified in historical and future simulations. We then examine multimodel composites of select atmospheric fields during these events in simulations of historical and future scenarios, enabling an identification of possible physical mechanisms that could contribute to the intensification of heavy rainfall events with climate change. Simulations show that additional moisture is transported into convective updrafts during heavy rain events in future simulations, driving stronger evaporative cooling from the entrainment of drier midtropospheric air. This results in the formation of a stronger low‐level cold pool, which enhances moisture convergence above the cold pool and increases rainfall rates during future heavy precipitation events. In addition, a warmer profile in future simulations might allow for heavier rainfall rates as a deeper atmospheric column can support additional collision‐coalescence of liquid hydrometeors.
Transient anomaly in fault zone‐trapped waves during the preparatory phase of the 6 April 2009, Mw 6.3 L'Aquila earthquake
Authors: Calderoni Giovanna , Rovelli Antonio , Di Giovambattista Rita 
Published: March 2015

AbstractFault zone‐trapped waves generated by repeating earthquakes of the 2009 L'Aquila seismic sequence show a sudden, up to 100% increase of spectral amplitudes 7 days before the main shock. The jump occurs 10 to 20 h after the ML 4.1, 30 March 2009 largest foreshock. The amplitude increase is accompanied by a loss of waveform coherence in the fault‐trapped wave train. Other geophysical and seismological parameters are known to have shown a sudden change after the 30 March foreshock. The concomitance of a consistent change in the fault zone‐trapped waves leads us to interpret our observation as due to a sudden temporal variation of the velocity contrast between the fault damage zone and hosting rocks in the focal volume. Fault zone‐trapped waves thus provide a refined time resolution for changes occurring near the rupture nucleation, with the indication of a strong variation in 1 day.
Climate‐forced changes in available energy and methane bubbling from subarctic lakes
Authors: Thornton Brett F. , Wik Martin , Crill Patrick M. 
Published: March 2015

AbstractStrong correlations between seasonal energy input and methane (CH4) bubbling (ebullition) in northern lakes suggest that energy proxies might provide a constraint on the magnitude of future CH4 emissions. Ebullition is a major pathway for transporting anaerobically produced CH4 from lake sediments to the atmosphere and represents a large unquantified CH4 source. In high‐latitude, postglacial lakes during the ice‐free season, solar shortwave energy input can constrain CH4 productivity via control of sediment temperature. Utilizing long‐term climatic predictors, we calculate CH4 ebullition from three subarctic lakes in northern Sweden over the period of 1916–2079. Using observed energy trends, the seasonal average lake CH4 ebullition is predicted to increase by 80% between the 1916–1926 decade and the 2040–2079 period. Present‐day seasonal average methane ebullition is estimated to have already increased 24% since the 1916–1926 decade.
Impacts of Arctic sea ice and continental snow cover changes on atmospheric winter teleconnections
Authors: Handorf Dörthe , Jaiser Ralf , Dethloff Klaus , Rinke Annette , Cohen Judah 
Published: March 2015

AbstractExtreme winters in Northern Hemisphere midlatitudes in recent years have been connected to declining Arctic sea ice and continental snow cover changes in autumn following modified planetary waves in the coupled troposphere‐stratosphere system. Through analyses of reanalysis data and model simulations with a state‐of‐the‐art atmospheric general circulation model, we investigate the mechanisms between Arctic Ocean sea ice and Northern Hemisphere land snow cover changes in autumn and atmospheric teleconnections in the following winter. The observed negative Arctic Oscillation in response to sea ice cover changes is too weakly reproduced by the model. The planetary wave train structures over the Pacific and North America regions are well simulated. The strengthening and westward shift of the Siberian high‐pressure system in response to sea ice and snow cover changes is underestimated compared to ERA‐Interim data due to deficits in the simulated changes in planetary wave propagation characteristics.
Phase transformations in an ascending adiabatic mixed‐phase cloud volume
Authors: Pinsky M. , Khain A. , Korolev A. 
Published: March 2015

AbstractRegimes of liquid‐ice coexistence that may form in an adiabatic parcel ascending at constant velocity at freezing temperatures are investigated. Four zones with different microphysical structures succeeding one another along the vertical direction have been established. On the basis of a novel balance equation, analytical expressions are derived to determine the conditions specific for each of these zones. In particular, the necessary and sufficient conditions for formation of liquid water phase within an ascending parcel containing only ice particles are determined. The results are compared to findings reported in earlier studies. The role of the Wegener‐Bergeron‐Findeisen mechanism in the phase transformation is analyzed. The dependence of the phase relaxation time on height in the four zones is investigated on the basis of a novel analytical expression. The results obtained in the study can be instrumental for analysis and interpretation of observed mixed‐phase clouds.
Mathematical Transformations
Authors: McGhee Des , Picard Rainer , Trostorff Sascha , Waurick Marcus 
Published: March 2015

Abstract
The article conbtains sections titled:

What are Transformations and Why are They Useful?

The Fourier Series Transformations

The Abstract Fourier Series

The Classical Fourier Series

The Fourier Series Transformation in

The
z
‐Transformation

The Fourier–Laplace Transformation

Convolutions as Functions of

Functions of

Convolutions

The Fourier–Plancherel Transformation

The Fourier–Laplace Transformation and Distributions

Impulse Response

Shannon's Sampling Theorem

The Fourier‐Sine and Fourier‐Cosine Transformations

The Hartley Transformations

The Mellin Transformation

Higher‐Dimensional Transformations

Some Other Important Transformations

The Hadamard Transformation

The Hankel Transformation

The Radon Transformation
Group Theory
Authors: Gilmore Robert 
Published: March 2015

Abstract
The article conbtains sections titled:

Introduction

Precursors to Group Theory

Classical Geometry

Dimensional Analysis

Scaling

Dynamical Similarity

Groups: Definitions

Group Axioms

Isomorphisms and Homomorphisms

Examples of Discrete Groups

Finite Groups

Infinite Discrete Groups

Examples of Matrix Groups

Translation Groups

Heisenberg Group

Rotation Group

Lorentz Group

Lie Groups

Lie Algebras

Structure Constants

Constructing Lie Algebras by Linearization

Constructing Lie Groups by Exponentiation

Cartan Metric

Operator Realizations of Lie Algebras

Disentangling Results

Riemannian Symmetric Spaces

Applications in Classical Physics

Principle of Relativity

Making Mechanics and Electrodynamics Compatible

Gravitation

Reflections

Linear Representations

Maps to Matrices

Group Element–Matrix Element Duality

Classes and Characters

Fourier Analysis on Groups

Irreps of

Crystal Field Theory

Symmetry Groups

Dynamical Groups

Conformal Symmetry

Atomic Shell Structure

Nuclear Shell Structure

Dynamical Models

Gauge Theory

Group Theory and Special Functions

Summary of Some Properties

Relation with Lie Groups

Spherical Harmonics and

Differential and Recursion Relations

Differential Equation

Addition Theorems

Generating Functions

Summary

Glossary
Monte‐Carlo Methods
Authors: Binder Kurt 
Published: March 2015

AbstractThe article conbtains sections titled:Introduction and OverviewRandom‐Number GenerationGeneral IntroductionProperties That a Random‐Number Generator (RNG) Should HaveComments about a Few Frequently Used GeneratorsSimple Sampling of Probability Distributions Using Random NumbersNumerical Estimation of Known Probability Distributions“Importance Sampling” versus “Simple Sampling”Monte‐Carlo as a Method of IntegrationInfinite Integration SpaceRandom Selection of Lattice SitesThe Self‐Avoiding Walk ProblemSimple Sampling versus Biased Sampling: the Example of SAWs ContinuedSurvey of Applications to Simulation of Transport ProcessesThe “Shielding Problem”Diffusion‐Limited Aggregation (DLA)Monte‐Carlo Methods in Statistical Thermodynamics: Importance SamplingThe General Idea of the Metropolis Importance‐Sampling MethodComments on the Formulation of a Monte‐Carlo AlgorithmThe Dynamic Interpretation of the Monte‐Carlo MethodMonte‐Carlo Study of the Dynamics of Fluctuations Near Equilibrium and of the Approach toward EquilibriumThe Choice of Statistical EnsemblesAccuracy Problems: Finite‐Size Problems, Dynamic Correlation of Errors, Boundary ConditionsFinite‐Size–Induced Rounding and Shifting of Phase TransitionsDifferent Boundary Conditions: Simulation of Surfaces and InterfacesEstimation of Statistical ErrorsSampling of Free Energies and Free Energy BarriersBulk Free EnergiesInterfacial Free EnergiesTransition Path SamplingQuantum Monte‐Carlo TechniquesGeneral RemarksPath‐Integral Monte‐Carlo MethodsA Classical Application: the Momentum Distribution of Fluid HeA Few Qualitative Comments on Fermion ProblemsLattice Gauge TheorySome Basic Ideas of Lattice Gauge TheoryA Famous ApplicationSelected Applications in Classical Statistical Mechanics of Condensed MatterMetallurgy and Materials SciencePolymer ScienceSurface PhysicsConcluding RemarksGlossary
Random Processes
Authors: Cruise James R. , Hryniv Ostap O. , Wade Andrew R. 
Published: March 2015

AbstractThe theory of stochastic processes is concerned with mathematical models of systems whose behavior is time dependent and incorporates randomness or uncertainty. The statistical structure of the system can be determined from the physical application in mind: a rich class consists ofMarkovprocesses whose future evolution depends on the past only through the present state of the system. We give a tour through some important examples of stochastic processes, primarily (but not exclusively) in a discrete setting where technicalities are minimized. Our tour is facilitated by a selection of mathematical tools of broad applicability, with a focus on generating functions and renewal ideas. We investigate in detail some illustrative specimens chosen for their relevance to applications in the physical sciences and for the mathematical ideas they elucidate.
Stochastic Differential Equations
Authors: Lord Gabriel J. 
Published: March 2015

AbstractWe give an introduction to Brownian motion and illustrate that although sample paths are continuous, they are nowhere differentiable. This leads to a discussion on white and colored noise. In Section 3.3, we introduce stochastic integration and look at the difference between Itô and Stratonovich integrals. We examine Itô stochastic differential equations (SDEs) in Section 3.4, giving some motivating examples, and use the Itô formula to find some exact solutions. We then consider Stratonovich SDEs and show how to convert between Itô and Stratonovich cases. We discuss numerical approximation of both Itô and Stratonovich SDEs and discuss the multilevel Monte Carlo method for weak approximation in Section 3.6. We conclude in Section 3.7 by looking at the link between SDEs and partial differential equations (PDEs) and introduce both the Fokker–Planck and backward Fokker–Planck equations.Throughout, the aim is to develop intuition by first examining simple, one‐dimensional examples before giving more general formulations and results. Also included are some basic algorithms for numerical approximation.
Computer Algebra
Authors: Davenport James H. 
Published: March 2015

AbstractThe article contains sections titled:IntroductionComputer Algebra Systems“Elementary” AlgorithmsRepresentation of PolynomialsGreatest Common DivisorsSquare‐free DecompositionExtended Euclidean AlgorithmAdvanced AlgorithmsModular Algorithms–IntegerModular Algorithms–PolynomialThe Challenge of Factorizationp‐adic Algorithms–Integerp‐adic Algorithms–PolynomialSolving Polynomial SystemsSolving One PolynomialReal RootsLinear SystemsMultivariate SystemsGröbner BasesRegular ChainsIntegrationRational FunctionsMore Complicated FunctionsLinear Ordinary Differential EquationsInterpreting Formulae as FunctionsFundamental Theorem of Calculus RevisitedSimplification of FunctionsReal ProblemsConclusion
Topics in Differential Geometry
Authors: Epstein Marcelo 
Published: March 2015

Abstract

This article assumes a basic knowledge of differentiable manifolds, vector fields, and differential forms (such as that provided in the article
DIFFERENTIABLE MANIFOLDS
). The first topic covered is the theory of integration of forms on oriented manifolds, whose most important result, generalizing and encompassing all the classical theorems of vector calculus, is the theorem of Stokes. The second topic is an introduction to Lie groups, namely, differentiable manifolds with a differentiablegroup structure. Important in themselves as the expression of symmetries in physical theories, Lie groups are also a necessary ingredient for the treatment of fiber bundles, which are manifolds with extra structure. Among the topics covered within this realm, principal bundles, linear connections, torsion, and curvature are particularly important in applications.
Functional Analysis
Authors: Exner Pavel 
Published: March 2015

Abstract
The article contains sections titled:

Banach Space and Operators on Them

Vector and Normed Spaces

Operators on Banach Spaces

Spectra of Closed Operators

Hilbert Spaces

Hilbert‐Space Geometry

Direct Sums and Tensor Products

Bounded Operators on Hilbert Spaces

Hermitean Operators

Unitary Operators

Compact Operators

Schatten Classes

Unbounded Operators

Operator Adjoint and Closure

Normal and Self‐Adjoint Operators

Tensor Products of Operators

Self‐Adjoint Extensions

Spectral Theory of Self‐Adjoint Operators

Functional Calculus

Spectral Theorem

More about Spectral Properties

Groups of Unitary Operators

Some Applications in Quantum Mechanics

Schrödinger Operators

Scattering Theory

Glossary
Numerical Analysis
Authors: Boulton Lyonell 
Published: March 2015

Abstract

Numerical analysis comprises a set of tools for the approximated solutions of mathematical problems. These include solutions to equations, optimization, direct computation of mathematical quantities and factorizations. The
methods
employed to determine these approximated solutions are usually implemented on electronic devices (e.g., scientific apparatus and computers). This chapter is concerned with a qualitative mathematical description of the very basic language of the theory, aimed at nonspecialists in the subject.
Partial Differential Equations
Authors: McGhee Des , Picard Rainer , Trostorff Sascha , Waurick Marcus 
Published: March 2015

Abstract
The article contains sections titled:

What are Partial Differential Equations?

Partial Differential Equations in with Constant Coefficients

Evolutionarity

An Outline of Distribution Theory

Integral Transformation Methods as a Solution Tool

Partial Differential Equations of Mathematical Physics

Initial‐Boundary Value Problems of Mathematical Physics

Maxwell's Equations

Viscoelastic Solids

Coupled Systems

Thermoelasticity

Piezoelectromagnetism

The Extended Maxwell System and its Uses
Thiazolium‐Based Catalysts for the Etherification of Benzylic Alcohols under Solvent‐Free Conditions
Authors: Bivona Lucia Anna , Quertinmont François , Beejapur Hazi Ahmad , Giacalone Francesco , Buaki‐Sogo Mireia , Gruttadauria Michelangelo , Aprile Carmela 
Published: March 2015

AbstractThiazolium and imidazolium hybrid materials were prepared by radical reactions between a mercaptopropyl‐modified SBA‐15 mesoporous silica and bis‐vinylthiazolium or bis‐vinylimidazolium dibromide salts. These hybrid materials were characterized by several techniques and were employed in the etherification reaction of 1‐phenylethanol. Solvent‐free conditions at 160 °C under different gas phases (oxygen, air, nitrogen and argon) were used. The thiazolium‐based material displayed excellent performances. Further studies were carried out using unsupported thiazolium salts, with or without a methyl group at the C‐2 position of the thiazolium moiety. These studies allowed us to propose a reaction mechanism. The supported thiazolium‐based material was successfully used in the etherification reaction of two other benzylic alcohols and also in seven consecutive cycles. This work represents the first use of thiazolium‐based compounds as catalysts for the etherification reaction of alcohols.magnified image