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Soil as a Basic Nexus Tool: Soils at the Center of the Food–Energy–Water Nexus
No full textPurpose of Review: Soil is the medium for plant growth and the substrate for all biogeochemical and biogeophysical processes. Soil’s unique natural organization forms the foundation of any food–water–energy nexus system. It forms a habitat for billions of diverse micro, meso, and macrofauna and flora and is the basis of numerous ecosystem services essential to human well-being and nature conservancy. It moderates soil hydrological processes within the entire vadose zone: which is part of the earth between the soil surface and the phreatic zone. Soil structure also supports numerous ecosystem services including nutrient transformation and availability, water quality and renewability, denaturing and transport of pollutants, and groundwater table fluctuations. It also moderates the soil–water–plant-energy nexus with the replenishement of green-water supply (from precipitation) for plants and soil biota, which in turn enables the production of biomass as a source of food, feed, fiber, and biofuel feedstock. Indeed, soil is a very large reservoir for water and carbon with strong influences on local, regional, and global climate. Also, the energy factor is connected with the climate change through soil–water–food–energy nexus because of numerous interlinked pathways including gaseous emissions, energy and food production, and recycling of nutrients and water at regional, national, and global scales. Through provisioning of numerous ecosystem services, the soil–water–food–energy–climate nexus is interwoven with the ecosystem security and functioning of planet’s four ecospheres (i.e., atmosphere, hydrosphere, lithosphere, and the biosphere). Therefore, the health of soil, plants, animals, people, and ecosystems is one and indivisible. Recent Findings: This interconnectivity is also the basis of the “4 per Thousand” initiative adopted by the COP21, the Climate Summit of 2015 in Paris, and “Adapting African Agriculture” (AAA) by COP22 in Morocco. Consequently, soil is not only a foundation for securing the natural resources: food, water and energy, but it is under desperate need to be integrated and appreciated in understanding the complex interconnectedness of any food, energy, water and soil system. Concentration and stock of soil organic carbon are the key soil properties that determine the physical, chemical, biological, and ecological properties and processes, and are major control of all nexuses described herein. Summary: This chapter presents a conceptual model and the role of soil as a naturally organized medium to protect global food, water, energy securities. Moreover, it elaborates on using soil as a basic nexus tool and proposes a paradigm shift in integrating soil and creating the food–energy–water–soil nexus
Using IT Design to Prevent Cyberbullying
No full textThe rise of social media has fostered increasing instances of deviant behavior. Arguably, the most notable of these is cyberbullying (CB), which is an increasing global concern because of the social and financial ramifications. This has necessitated a new line of research aimed at understanding and preventing CB. Although much progress has been made in understanding CB, little is known about how to prevent it, especially through the information technology (IT) design. Based on the need for a better causal theory and more effective empirical methods to investigate and mitigate this phenomenon, we leverage the control balance theory (CBT) for system design. Our model examines the causes of CB from several novel angles, including (1) the strong nonlinear influence of control imbalances on CB, and (2) using the concept of fit to understand how different design features of information technology artifacts influence factors such as deindividuation and accountability, thus affecting control imbalance. Using an innovative factorial survey method that enabled us to manipulate IT design features to obtain a nuanced view, we tested our model with 507 adults and found strong support for our model. The results show that IT design features create a strong CB opportunity for individuals who perceive that they are controlled by others. Whether this perception is real or imagined, it creates a sense of vulnerability, prompting them to engage in CB. We can thus propose specific IT design feature manipulations that can be used to discourage CB. These results should have salient implications for researchers and social media designers, especially in developing social media networks that are safe, supportive, responsible, and constructive
Panther - October 13th 2017
Get PDFhttps://digitalcommons.pvamu.edu/pv-panther-newspapers/2022/thumbnail.jp
Function of Personal Growth Initiative on Posttraumatic Growth, Posttraumatic Stress, and Depression Over and Above Adaptive and Maladaptive Rumination
No full textObjectives: The current study examined whether various types of rumination are distinguishable and the effects of personal growth initiative (PGI) on posttraumatic growth, posttraumatic stress, and depression through adaptive and maladaptive rumination. Method: Sample included 292 college students who experienced a potentially traumatic event (PTE). Results: Intrusive and deliberative rumination were found to be distinct factors. However, brooding and reflection, thought to be separate aspects of depression, were a single factor. PGI was positively associated with growth and negatively associated with depression for both genders, and a negative relationship was found between PGI and posttraumatic stress among women. Indirect effects of PGI were found on posttraumatic stress and growth through different forms of rumination. These relations did not change after including the covariates (i.e., time since the trauma, direct exposure, and intentional harm). Conclusion: The study provides new insight integrating rumination from the depression literature in the context of trauma and a potential benefit in applying PGI in alleviating pathology after a PTE and facilitating growth
Despite Access to Antiretrovirals for Prevention and Treatment, High Rates of Mortality Persist among HIV-infected Infants and Young Children
No full textBackground: Outcomes of HIV-infected children before widespread use of antiretroviral therapy (ART) for treatment and prevention of mother-to-child transmission (PMTCT) have been well characterized but less is known about children who acquire HIV infection in the context of good ART access. Methods: We enrolled newly diagnosed HIV-infected children ≤24 months of age at 3 hospitals and 2 clinics in Johannesburg, South Africa. We report ART initiation and mortality rates during 6 months from enrollment and factors associated with mortality. Results: Of 272 children enrolled, median age 6.1 months, 69.5% were diagnosed during hospitalization. By 6 months postenrollment, 53 (19.5%) died and 73 (26.8%) were lost-to-follow-up. Using Kaplan-Meier analysis, the probability of death by 6 months after enrollment was 23.5%. The median age of death was 9.1 months [95% confidence interval (CI): 8.6-12.0]. Overall, 226 (83%) children initiated ART which was associated with a 71% reduction in risk of death [hazard ratio (HR) = 0.29 (95% CI: 0.15-0.58)]. In multivariable analysis of infant factors, weight-for-age Z score \u3c-2 standard deviation (SD) [HR = 2.43 (95% CI: 1.03-5.73)], CD4 \u3c20% [HR = 3.29 (95% CI: 1.60-6.76)] and identification during hospitalization [HR = 2.89 (95% CI: 1.16-7.25)] were independently associated with mortality. In multivariable analysis of maternal factors, CD4 ≤350/no maternal ART was associated with increased mortality risk [HR = 2.57 (95% CI: 1.19-5.59)] versus CD4 \u3e350/no maternal ART; exposure to maternal/infant antiretrovirals for PMTCT was associated with reduced mortality risk [HR = 0.53 (95% CI: 0.28-0.99)] versus no PMTCT. Conclusions: ART initiation is highly protective against death in young children. However, despite improved access to ART, young children remain at risk for early death; innovative approaches to rapidly diagnose and initiate treatment as early in life as possible are needed
Sperm Chromatin Dynamics Associated with Male Fertility in Mammals
No full textInstead of two protamines (PRM1 and PRM2) as in human and mouse sperms, presence of only PRM1 in bull sperm raises an interesting question about the mechanism(s) regulating sperm chromatin structure. During spermatogenesis, spermatozoa that are present in syncytium share mRNA and proteins through cytoplasmic bridges and are phenotypically diploid. Chromatin remodeling occurs during spermatogenesis where linker histones are gradually replaced by testis-specific variants, followed by the replacement of histones with transition proteins and then with protamines. Increased percentage of histone retention is expected to cause infertility in males. Although protamines are involved in sperm chromatin condensation and function, there is restrictive positive selection on only a few functional sites. Improper packaging of sperm DNA caused partly by reduced protamination predisposes sperm DNA to damage, which then interferes with fertilization and early embryonic development. Abnormal chromatin condensation in sperm during spermatogenesis and abnormal chromatin decondensation during pronucleus formation (postfertilization) can result in reproductive problems
A quantum simulation approach for a three-dimensional Ising spin model - Comparison to mean field theory
No full textWe use a recently developed quantum simulation approach to study the properties of a three-dimensional Ising model consisting of S = 1/2 quantum spins localized at the sites of a simple cubic lattice. We assume nearest-neighbor interaction between spins with an exchange interaction that can be either ferromagnetic or antiferromagnetic. It is found that the computational method quickly converges towards the expected equilibrium spin configurations. The resulting spontaneous magnetization curves corresponding to the two types of magnetic interactions under consideration were found to be almost identical to the ones obtained via quantum mean field theory at all temperatures. The derived total energies, total free energies, magnetic entropies and specific heats per mole of spins show no sizeable differences from known theoretical values. Furthermore, the results of the simulations for two different 3D Ising systems containing 4×4×4 and 20×20×20 spins localized at the sites of a simple cubic lattice were found to be almost identical to each other. This finding suggests that the self-consistent algorithm approach of the current simulation method allows one to obtain the physical bulk properties of a large magnetic system by relying on simulations of a much smaller spin system sample. Therefore, the method presently considered appears to be not only very accurate as gauged by comparison to mean field theory, but also able to greatly increase the speed of simulations
Two-cycle optimization in replacement models with non-exponential technological improvement
No full textOptimal asset replacement is analysed under non-exponential technological improvement, whereby the asset capital cost and the operational cost reduce for newer assets, and the relative rate of this decrease varies with time. We establish that the optimal lifetime of sequentially replaced assets increases if the relative rate of technological change decreases, and converse. Next, the two-cycle replacement algorithm is employed to take the unequal asset lifetime into account. The algorithm is adjusted to the case of several discrete estimates of changing asset costs and demonstrates good performance in various scenarios of improving technology
Acidic ionic liquid polymers: poly(bis-imidazolium-p-phenylenesulfonic acid) and applications as catalysts in the preparation of 1-amidoalkyl-2-naphthols
No full textA new class of polymeric acidic ionic liquids with imidazolium hydrogen sulfate and p-phenylene sulfonic acid units built into the main polymer chain were prepared by a simple two step method in 87–89% yield. These new polymers were characterized by elemental analysis, 1H, 13C NMR, FT-IR, TGA and GPC. The catalytic activity of sulfonic acid group functionalized ionic liquid polymers was demonstrated through the synthesis of 1-amidoalkyl-2-naphthols in 78–90% yield by condensation of 2-naphthol, benzaldehyde and amides without a solvent at 100 °C
Proportional Reversed Hazard Rate Models with Exponential Baseline
Get PDFThe proportional hazard regression models have been used extensively in survival analysis to understand and exploit the relationship between survival time and covariates. For left censored survival times, reversed hazard rate functions are more appropriate. In this paper, we discuss a parametric proportional reversed hazard rates model using exponential baseline. The estimation for the parameters are discussed. We also assess the performance of the proposed procedure based on a large number of Monte Carlo simulations. Finally, we illustrate the proposed method using a real case example and then we show that it provides a good and better fit than the usual proportional hazards model