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Origin of the anisotropic Coulomb interaction potential for a two-dimensional system of charged particles with anisotropic mass
No full textThere have been several studies that have considered an anisotropic Coulomb interaction potential of a specific form to model anisotropic quantum Hall states of two-dimensional systems of electrons in a perpendicular constant magnetic field. The motivation and justification behind such a choice is tacitly implied without providing too many details. This work explains the physical reasons that lead to an anisotropic Coulomb interaction potential of such a form for the case of a two-dimensional system of charged particles with anisotropic effective band mass
The Mental Health and Service Use of Texas Law Enforcement Officers
No full textAs law enforcement officers are regularly exposed to unique stressors during the course of their occupation, they are at elevated risk of developing mental health problems. Indeed, previous literature has identified that law enforcement officers endorse higher rates of mental health problems than the general population. Despite this, many officers do not seek mental health treatment. Lack of service utilization is particularly concerning as mental health problems have been associated with deficits in job performance. The current study aimed to identify rates of mental health problems with the Texas law enforcement community, as well as rates of treatment seeking for job-related incidents. This study identified that mental health problems are common among officers in Texas, with the three most frequently endorsed conditions being: sleep disturbances (45.00%), depression (32.90%), and PTSD (12.90%). Further, only 1.40% of officers were currently in mental health treatment and 17.90% had previously sought out mental health related treatment. These findings, their implications, and future directions are discussed
An Investigation Of Principals’ Social Justice Leadership And Black Male Academic Achievement
Get PDFBlack males in K-12 school systems across the nation continue to face formidable challenges such as low graduation rates, overrepresentation in special education, high out-of-school suspension rates, and underperformance in the classroom (Bryan, 2020; Grace & Nelson, 2019; Johnson & Bryan, 2017; Powell, 2018). Despite decades of research devoted to addressing the educational and social injustices Black males face, many scholars contend that such attention has resulted in minimal change, and a revised narrative for managing the state of Black males is needed (Adedoyin et al., 2019; Carter, 2019; Johnson & Bryan, 2017).
Some scholars have insisted that the academic outcomes among racial groups can be addressed through social justice leadership (Ezzani, 2020; Gullo & Beachum, 2019; Ogden, 2017; Theoharis, 2009). Additionally, they contend that social justice leadership of the principal is critical in developing equitable educational opportunities for diverse students (Beachum & Gullo, 2020; Ezzani, 2020; Grogan, 2017; Theoharis, 2009).
This quantitative study was to investigate how the level at which principals engage in social justice leadership behaviors is related to Black male academic achievement. Consequently, the study relied on Ajzen’s (1991) Theory of Planned Behavior (TPB) which postulates that intentions to perform various behaviors are subjected to the attitude toward the behavior, subjective norms, and perceived behavioral control.
Four research questions guided this study. They were:
1. What is the relationship between the level at which principals engage in school-specific social justice leadership behaviors and Black male Algebra and English 1 EOC performance?
2. What is the relationship between the level at which principals engage in community-minded social justice leadership behaviors and Black male Algebra and English 1 EOC performance?
3. What is the relationship between the level at which principals engage in self-focused social justice leadership behaviors and Black male Algebra and English 1 EOC performance?
4. Can overall social justice leadership behaviors of school principals (school-specific, community-minded, and self-focused) predict Black male Algebra and English 1 EOC performance?
The implications for research and practice are that the results of this study provide educational leaders and policymakers with a lens through which strategies could be created to break the cycle of educational racism faced by Black males and students of color. In so doing, challenges related to low graduation rates, overrepresentation in special education, high out-of-school suspension rates, and underperformance in the classroom will be easier to overcom
Pyrolysis Route for the Conversion of Bacterial Cellulose to Graphene Oxide
No full textA novel route to graphene oxide (GO) is presented where the cellulosic biofilm formed at the air-water interface as a waste product in the kombucha tea beverage fermentation industry is used as the renewable carbon source. A kombucha pellicle was first purified by treatment with 1.0 mol/L aqueous NaOH at 90 °C and bleaching with 1.5% (w/w) aqueous NaOCl at 23 °C and then pyrolyzed at 600-800 °C in air or under an inert atmosphere. The highest GO yield of 22.5% (w/w) was obtained by pyrolysis at 600 °C under Ar. The product was identified as GO using FT-IR, Raman, XPS, XRD, and scanning electron microscopy. The ability to transform to GO by simple pyrolysis may be due to an extraordinarily highly ordered arrangement of glucan chains in kombucha pellicle fibrils. This discovery provides the first sustainable feedstock-based, simple, green route to GO, without the use of concentrated strong acids and oxidizing agents used in current Hummers\u27 method
Catalytic upgrading of biomass derived furans
No full textThe current interest in biomass derived renewable furan derivatives furfural and 5-hydroxymethylfurfural commonly known as biofurans is due to their ready accessibility through dehydration of abundant cellulosic biomass derived monosaccharides. However, an upgrading to more stable compounds is an essential step for these materials in many sustainable fuel and chemical industry applications due to their instability and facile polymerization to humins. The aim of this article is to cover all aspects of catalytic upgrading reactions of biofurans, especially focusing on the developments in the last five years. The importance of this class of renewable feedstocks, preparation from monosaccharides as well as the diversity of possible transformations are discussed in the introduction sections of this review. The recent advances in catalytic reductions and oxidations of biofurans at CHO, OH functional groups, in ring system as well as rearrangements to form more stable value-added derivatives are reviewed. In addition, recently developed catalytic methods in carbon number upgrading of biofurans through condensation reactions and further conversions to renewable synthetic fuel range molecules are discussed in the article
ICTs as challenges to Enacting IS project control: An interpretive case study of an ERP implementation
No full textThis study investigates challenges posed by Information and Communication Technologies (ICTs) in the enactment of Information Systems (IS) project control. Using the control perspective developed by the sociologist John Law, we conducted an interpretive study of an Enterprise Resource Planning System implementation at a large public university system. From our investigation, four salient insights emerge. These insights are accompanied by corresponding assertions that demonstrate how ICTs, through varied forms of involvement, may challenge IS project control enactment. We integrate these insights for deeper illumination and conclude with contributions and implications of this study
Using a Mock Trial to Teach Science and the Law
No full textOver the course of 3 years, the Political Science and Biology Programs at a regional HBCU have built a curricular learning community centered on a mock trial competition, where a microbiology course was paired with an introductory legal studies course. Over the course of a semester, students enrolled in both courses studied a real appellate case that dealt with some aspect of forensic science (DNA evidence for example). The legal studies students were to act as prosecution and defense and the microbiology students played the role of expert witnesses and consultants. To be successful, students had to build an interdisciplinary team, outline their side’s case, and learn scientific and legal principles. This paper evaluates the impact of this experience on student learning using a mixed-methods approach. Students completed a self-reported knowledge survey and participated in a focus group debriefing session. Students report important gains in understanding the legal system and aspects of forensic science
Impact of interfacial barriers onthe oxidative stability of lipophilicbioactive compounds in oil-in-wateremulsions - The case of lutein
No full textOils, which consist of fatty acids (FA), are dispersed in the aqueous phase of food emulsions. Under food processing conditions (e.g., high heat, shear forces), and in the presence of oxygen, polyunsaturated fatty acids (PUFA) may become oxidized. It is generally accepted that the interfacial region, which is the contact region between the oil phase and the aqueous phase, represents a critical area in the emulsion system with regard to the development of oxidation. A better understanding of the relationship between the interfacial region (oil droplet size) and interfacial composition (emulsifier type) may allow the creation of stable food emulsions against oxidation. Emulsifiers work by stabilizing oils suspended in water, and this is achieved electrostatically. A part of an emulsifier is attracted to water while its other part is attracted to the oil. The effects of emulsifiers in limiting the transport of free radicals across the emulsion interface and its impact on the oxidative stability of lipophilic bioactive compounds is an area of active research. The transport of free radicals across the emulsion interface can be measured using a peroxide method. The free radicals are generated in the aqueous phase using 2,2\u27-azobis (2-amidinopropane) dihydrochloride (AAPH). The peroxide method can reveal the barrier properties of emulsifiers towards a water-soluble radical initiator (AAPH) in emulsion systems. Lutein, a xanthophyll carotenoid, was selected as a lipophilic bioactive compound (phytonutrient) model to evaluate the interfacial barrier properties of emulsifiers in an emulsion-based delivery system prepared with corn oil, which is high in PUFA. The lutein-loaded emulsions were formulated with the following emulsifiers: bovine casein; caprine casein (αs1-I); and caprine casein (as1-II). The peroxide value (PV) demonstrated that lutein-loaded emulsions stabilized with caprine casein (αs1-II) provided a significantly (p \u3c 0.05) enhanced interfacial barrier limiting the transport of peroxyl radicals across the oil-water interface. In agreement with PV measurements, chemical (color) stability results showed that lutein was most stable (p\u3c0.05) under the photo-oxidative conditions when emulsions were stabilized by caprine casein (αs1-II). The better interfacial barrier properties exhibited by caprine casein (αs1-II) can be used to create lutein-loaded emulsion formulations with improved chemical (color) stability for food and beverage applications.
Analysis and specification of starch granule size distributions
No full textStarch from all plant sources are made up of granules in a range of sizes and shapes having different occurrence frequencies, i.e., exhibiting a size and a shape distribution. Starch granule size data determined using several types of particle sizing techniques are often problematic due to poor reproducibility or lack of statistical significance resulting from some insurmountable systematic errors, including sensitivity to granule shapes and limits of granule-sample sizes. We outlined a procedure for reproducible and statistically valid determinations of starch granule size distributions using the electrical sensing zone technique, and for specifying the determined granule lognormal size distributions using an adopted two-parameter multiplicative form with improved accuracy and comparability. It is applicable to all granule sizing analyses of gram-scale starch samples, and, therefore, could facilitate studies on how starch granule sizes are molded by the starch biosynthesis apparatus and mechanisms; and how they impact properties and functionality of starches for food and industrial uses. Representative results are presented from replicate analyses of granule size distributions of sweetpotato starch samples using the outlined procedure. We further discussed several key technical aspects of the procedure, especially, the multiplicative specification of granule lognormal size distributions and some technical means for overcoming frequent aperture blockage by granule aggregates
(R1493) Discussion on Stability and Hopf-bifurcation of an Infected Prey under Refuge and Predator
Get PDFThe paper deals with the case of non-selective predation in a partially infected prey-predator system, where both the susceptible prey and predator follow the law of logistic growth and some preys avoid predation by hiding. The disease-free preys get infected in due course of time by a certain rate. However, the carrying capacity of the predator population is considered proportional to the sum-total of the susceptible and infected prey. The positivity and boundedness of the solutions of the system are studied and the existence of the equilibrium points and stability of the system are analyzed at these points. The effect of the infected prey-refuge on each population density is also discussed. It is observed that a Hopf-bifurcation may occur about the interior equilibrium, where the refuge parameter is considered as the bifurcation parameter. The analytical findings are illustrated through computer simulation using MAPLE that show the reliability of the model from the ecological point of view