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Green Synthesis of Silver Nanoparticles with Antimicrobial Properties Using Phyla dulcis Plant Extract
No full textFoodborne illnesses caused by the consumption of food contaminated with foodborne pathogens at infectious doses are becoming a common health issue throughout the world. Metal nanoparticles with potential antimicrobial properties are an area that can be explored to discover novel antimicrobial agents. The traditional synthesis methods of metal nanoparticles involve the use of toxic chemicals and the generation of harmful byproducts. In this study, a greener method to synthesize silver nanoparticles (AgNPs) with potential antimicrobial properties was investigated. The aqueous extract of the medicinal plant Phyla dulcis Trev. (verbenaceae) was used as the reducing and stabilizing agent to synthesize AgNPs using microwave irradiation. The formation of AgNPs was confirmed using ultraviolet-visible spectroscopy by the appearance of characteristic surface plasmon resonance peaks in the 430-440 nm wavelength range. The size and stability of the AgNPs were studied using Zetasizer nano-series for 5 weeks after synthesis. The average particle size remained between 63 and 76 nm during the first 4 weeks and increased to 114 nm in the fifth week showing possible aggregation after the fourth week. The zeta potential remained between -20 and -24 mV throughout the 5 weeks showing relatively good stability. Scanning electron microscopy/energy dispersive X-ray spectroscopy showed the association of phytoconstituents with the AgNPs. X-ray photoelectron spectroscopy analysis confirmed the formation of metallic nanoparticles starting from silver nitrate. Finally, the AgNPs were tested to be effective against Escherichia coli O157:H7 (ATCC 43888), Salmonella Typhimurium (novobiocin and nalidixic acid resistant strain), Listeria monocytogenes (4b; ATCC 19115), and Staphylococcus aureus (ATCC 6538) strains, which are known to be common foodborne pathogens
Optimal asset replacement: Profit maximization under varying technology
No full textThe paper analyzes a profit-maximizing serial replacement problem under variable asset productivity, operating cost, and replacement cost that depend on asset age and installation time. The majority of modern asset replacement models minimize costs. The authors examine and highlight essential differences between profit-maximizing and cost-minimizing replacement strategies in the infinite-horizon framework. Next, they construct and analyze an effective multi-cycle replacement algorithm that approximates the infinite-horizon solution with non-equal asset lifetimes. Numeric simulation illustrates theoretic outcomes and demonstrates a good performance of the constructed algorithm under different patterns of changing technology
Copula Approach for Developing a Biomarker Panel for Prediction of Dengue Hemorrhagic Fever
No full textThe choice of variable-selection methods to identify important variables for binary classification modeling is critical for producing stable statistical models that are interpretable, that generate accurate predictions, and have minimal bias. This work is motivated by the availability of data on clinical and laboratory features of dengue fever infections obtained from 51 individuals enrolled in a prospective observational study of acute human dengue infections. Our paper uses objective Bayesian method to identify important variables for dengue hemorrhagic fever (DHF) over the dengue data set. With the selected important variables by objective Bayesian method, we employ a Gaussian copula marginal regression model considering correlation error structure and a general method of semi-parametric Bayesian inference for Gaussian copula model to estimate, separately, the marginal distribution and dependence structure. We also carry out a receiver operating characteristic (ROC) analysis for the predictive model for DHF and compare our proposed model with the other models of Ju and Brasier (Variable selection methods for developing a biomarker panel for prediction of dengue hemorrhagic fever. BMC Res Notes 6:365, 2013) tested on the basis of the ROC analysis. Our results extend the previous models of DHF by suggesting that IL-10, Days Fever, Sex and Lymphocytes are the major features for predicting DHF on the basis of blood chemistries and cytokine measurements. In addition, the dependence structure of these Days Fever, Lymphocytes, IL-10 and Sex protein profiles associated with disease outcomes was discovered by the semi-parametric Bayesian Gaussian copula model and Gaussian partial correlation method
The unintended consequences of promising black Americans reparations
No full textIn this article, I offer the opposing view (con-side) against reparations for American slavery, as if in a forensic debate before a moot court: I presume the American public will judge the merits of my opposing arguments. I oppose reparations for slavery based on: 1) the legal standard of culpability, 2) the “clean-hands doctrine, 3) Black people who were themselves slave owners, and 4) fairness in the administration justice. While anyone else is welcome to argue the pro-side, I argue the con-side of the following proposition: America owes Black Americans reparations because of its history of plantation slavery, which has privileged White Americans economically over Black Americans. I provide a plethora of evidence that reparations and justice are incompatible in the application of American justice. Moreover, any law requiring reparations for slavery could create an unintended liability for far too many Black Americans whose ancestry extends far beyond Sub-Saharan Africa
Information Technology and organizational innovation: Harmonious information technology affordance and courage-based actualization
No full textResearchers and practitioners have long believed that information technology (IT) is a key tool for fostering innovation. However, there is a certain inconsistency in the literature, which makes it challenging for researchers to figure out exactly how and why IT plays such a pivotal, strategic organizational role. The motivation for this research is the multiple contradictory results reported by studies investigating the influence of information technology (IT) on organizational innovation. This study utilizes a fit-based perspective in an attempt to disentangle these contradictions. Using Venkatraman\u27s (1989) seminal paper on fit, we conceive of two critical fit-based concepts: harmonious IT affordance in an organization (HITA) and a subsequent fit between HITA and organizational courage. HITA reflects a covariance fit (coalignment) between the three major IT affordances in an organization—collaborative affordance, organizational memory affordance, and process management affordance. Organizational courage reflects the boldness (risk-taking ability) of the organization. Finally, HITA and organizational courage represent a matching fit (reflected as actualized HITA) that influences two kinds of innovation: exploratory and exploitative. Two studies, conducted in the US and Chinese contexts, provide support for this theory. The main contribution of the paper is in showing that IT can lead to innovation if (a) organizational IT affordances harmoniously coalign (as HITA); (b) and, organizational courage acts as a powerful contingency that actualizes HITA, and this actualized HITA influences innovation
Soil CO2 emission in response to organic amendments, temperature, and rainfall
No full textVegetated land surfaces play an important role in determining the fate of carbon in the global carbon cycle. However, our understanding of the terrestrial biosphere on a global scale is subject to considerable uncertainty, especially concerning the impacts of climatic variables on the carbon cycle. Soil is a source and also a sink of CO2 exchange and helps in carbon sequestration. Agricultural management practices influence soil water dynamics, as well as carbon cycling by changing soil CO2 emission and uptake rates. The rate of soil CO2 emission varies for different crops and different organic amendments. The major goal of this study was to assess the impacts of the type and rate of organic amendment on soil CO2 emission in a collard greens crop grown in the southeast Texas environment. Thirty-six plots were developed to grow collard greens on Prairie View A&M University’s Research Farm. Three types of organic amendments (Chicken manure, Dairy manure, and Milorganite), at four levels of application (0, 168, 336, and 672 kg N/ha) were used and replicated three times. Each organic amendment type was applied to nine randomly selected plots. Three random plots were used as a control in each row. We measured daily soil CO2 emission for the first two weeks and every other day in a week during the experiment. We evaluated the effects of organic amendments and the application rates on soil CO2 emission for collard greens during two growing seasons. The results showed higher the application rates for each organic amendment, higher the CO2 emissions from the soil. The results also showed higher cumulative CO2 emissions for the soils amended with chicken manure and milorganite, but lowest for the soils amended with dairy manure. This field experiment and analyses help better understand the temporal and spatial variations of soil CO2 emission, and also help to develop best management practices to maximize carbon sequestration and to minimize soil CO2 emissions during the growth periods of collard greens under changing temperatures using different organic amendments, and application rates
Actor–observer asymmetry in perceptions of parole board release decisions
No full textIn the current study, the actor–observer effect is tested with both mock parole board members and the public evaluating the responsibility of parole board members for a decision resulting in a parolee reoffending and committing a murder. Participants (two samples with a combined N = 1317) were randomly assigned to act as a mock parole board member and make a decision (which ended in the parolee reoffending) or as a member of the public who read a story about the same parole decision and outcome. Findings suggest that the traditional actor–observer asymmetry emerged across blame and responsibility concepts, emotion and moral judgments. Overall, the public held harsher judgments than the mock parole board members. Implications regarding self-enhancement, methodology and attribution theory are discussed
Understanding the Impetus for Modern Student Activism for Justice at an HBCU: A Look at Personal Motivations
No full textThis study examined university students’ motivations for engaging in activism for justice. Of interest is what moved a sample of university youth at a historically Black university to get involved in the Jena Six protest of September 2007 given that cases of injustice have remained fairly commonplace in recent decades for persons of color. To answer this question, a qualitative text analysis of 80 essays that were written by undergraduate students as a requirement for a seat on a bus to the protest was performed. Data were coded initially using etic codes from the literature on reasons for student activism. The findings indicate that for males anger is a significant catalyst for action. In contrast, females described a transformative future orientation for their offspring as motivating them to stand and to march in the interest of justice. Such insights are likely of interest to those leading efforts for social justice
Challenges and Potentials for Soil Organic Carbon Sequestration in Forage and Grazing Systems
No full textForage and grazing (FG) systems can store a substantial amount of soil organic carbon (SOC) under appropriate land use management and reduce atmospheric CO2 concentrations. Increasing SOC levels along with many interlinked ecosystem services are essential for increased productivity and sustainability of FG lands (FGLs). Although adoption of improved management practices (MPs) that support SOC sequestration (SOCq) is necessary, clear understandings of challenges and opportunities which are sometimes unique to individual FGLs, are also important for implementation of MPs. The objective of this forum paper is to explore the latest scientific knowledge on opportunities to address major challenges for increasing SOCq in FGLs. In intensively managed FGLs where the goal is often to maximize yields, lands are heavily fertilized and thus, usually drive towards SOC loss. Diversifications of both forage and grazing species along with strategic grazing plans have been proven as effective MPs for increasing SOCq. However, challenge of maintaining productivity levels still remains. Implementing improved grazing for nutrient cycling and integrating forage diversification for increased biodiversity are found to improve soil health attributes, which are critical for SOCq. However, to achieve this, we also need to consider site- and soil- specific factors. Extreme climatic events often lead to a decline in soil fertility status, SOCq and overall productivity of FGL systems. To address these challenges, uses of models to simulate the FGL systems and have definite choices of suitable MPs are helpful. However, we must be able to access a wide range of datasets to develop system-level adaption strategies that are effective in mitigating these adverse effects. Ultimately, participatory research with novel views and improved perceptions based on the value of SOCq and long-term benefits of the implementation of the best MPs and developing education and outreach materials to enrich the producers’ knowledge gaps are helpful for climate-resilient FGL systems
Effect of Feeding a Low Level of Encapsulated Fish Oil to Dairy Goats on Milk Yield, Composition, and Fatty Acid Profile
No full textContradictory results have been found in the response of dairy goats to the supplementation of fish oil in their diet to improve the n-3 polyunsaturated fatty acids (PUFA) in milk. The responses to the inclusion of fish oil in the diet of ruminants either induced milk fat depression, increased milk fat content, and/or negatively impacted milk yield. The objective of this study was to determine whether including a low dose of encapsulated fish oil in the diet of goats can modify yield, milk composition, and the fatty acid (FA) profile of milk. Ten Alpine goats were divided into two homogeneous subgroups and assigned to either the control or experimental diet. The control animals received the basal diet without supplementation of fish oil, whereas the experimental group was given the same basal diet supplemented with encapsulated fish oil (1.14 g /kg of concentrate) for 56 days. Milk samples were analyzed for chemical composition and FA profile. The inclusion of encapsulated fish oil in the goat diet did not affect the yield and composition of goat milk. The effect of diet was not significant on the FA profile of goat milk, except that 20:0 was lower (P \u3c 0.05) in the milk of goats that received fish oil. The low dose of encapsulated fish oil supplement used in this study did not impact (P \u3e 0.05) the PUFA content of goat milk or milk composition and yield; however, the atherogenicity index (AI), which is beneficial to heart health, was lower (P \u3c 0.05) in the milk of goats that received fish oil as a supplement in their diet compared to the control