Molecular Kondo effect in flat-band lattices

The Kondo effect of a single magnetic impurity embedded in the Lieb lattice is studied by the numerical renormalization group. When the band flatness is present in the local density of states, it quenches the participation of all dispersive electrons in the Kondo singlet formation, and reduces the many-body Kondo problem to a two-electron molecular Kondo problem. The two-electron analog of the many-body Kondo singlet, a quantum entanglement of two spins, is stable at low temperature, and the impurity contributions to thermodynamical and dynamical quantities are qualitatively different from that obtained in the conventional Kondo effect in systems without flat bands. The existence conditions of the molecular Kondo effect in narrow band systems are also discussed

EXPERIMENTAL RESULTS OF ADSORPTION OF Ni (II) FROM WASTEWATER USING COFFEE HUSK BASED ACTIVATED CARBON

In recent years, the studies on finding the low cost methods to remove metal ions have been increased. Use of agricultural wastes such as coffee husk, coffee residue, coconut fiber, rice husk, peanut shells, cob, etc. as adsorbents to remove heavy metals, pollutants in wastewater has been of great concern in Viet Nam and regional countries. The results showed that the material from coffee husk had superior adsorption. In this study, the coffee husk was heated in Ar gas at temperatures of 300 oC, 400 oC, 500 oC, 600 oC for 30 minutes, 60 minutes and 90 minutes, then was denatured by impregnation with HNO3 at different concentrations (1M, 3M, 5M). The adsorbent products from the above process from coffee husk were tested to find the best technical solution by studying the influences of pH (2 ÷ 9), contact time (10 ÷ 100 min), adsorbent dose (0.2 ÷ 10 g/L) and initial concentration Ni(II) (10 ÷ 60 mg/L). The research results showed that while the activated carbon samples treated at 400 oC in 30 minutes had Ni (II) adsorption capacity of 1.97 mg/g, the activated carbon by HNO3 had Ni (II) adsorption higher capacity, maximum adsorption capacity is 21.14 mg/g (more than 10 times in comparison with the non-denatured or non-modified coal).

Corruption: Case Studies of Vietnam and Italy

Corruption is morally and legally wrong. Despite many governmental policies and strategies designed to combat corruption, it still persists in most parts of the world. To understand why corruption is so persistent and pervasive, it is necessary to recognize the perceptions of the beneficiaries and victims of the issue and to comprehend the extent to which cultural biases influence individuals’ decisions to give in to corruption. Acquiescence to dishonest and fraudulent behavior can foster political corruption in many countries. Vietnam and Italy were selected as case studies for this paper. Using the case studies of these two different countries will provide an explanation of how different cultural and social contexts can influence the prevalence of corruption. This paper also endeavors to give some practical recommendations to policy makers and to activists to ponder upon

A study of Fez1 and Fez2. Establishment of Fez1 and Fez2 knock out cells lines. Localization of Fez1 and Fez2

Autophagy is an essential cellular process that is important to maintain homeostasis by degrading proteins, lipids and organelles during critical times like cellular or environmental stress conditions. Autophagy plays a critical role in human pathologies, since defective autophagy can lead to diseases like cancer, neurodegenerative- and inflammatory diseases. Fez1 (Fasciculation and elongation protein zeta 1) is a protein that has been reported to inhibit autophagy. In the first part of this study an attempt to establish stable knock out cell lines of Fez1, its homologue Fez2 and double Fez1-Fez2 by using CRISPR/Cas9 technology was performed. The knock out strategy was applied on two different human cell lines, Hek293 Flp-In and the neuronal cell line SH-SY5Y, and more than 200 putative clones were screened. Unfortunately, none of them displayed complete knock out of Fez1 or Fez2. This may indicate that Fez1 and Fez2 are essential for cell survival or cell growth in these cell lines. In the second part of this study, confocal imaging was applied to study the localization of Fez1 and Fez2, and if they colocalized with proteins involved in autophagy and intracellular transport. Interestingly, upon over-expression both Fez1 and Fez2 colocalized with proteins involved in autophagosome initiation and maturation like WIPI2 and the Atg8 proteins. However, they did not colocalize with syntaxin17, which is involved in the fusion step between autophagosomes and lysosomes. Both proteins also colocalized with tubulin and the transport protein KIF5B. This may suggest a role for Fez1 and Fez2 in the transport of early autophagosomes. The colocalization with tubulin, specifically γ tubulin, was verified at the endogenous level by immunostaining

Hedonic regression model for coffee futures: an analysis of effect of weather, exchange rate, past price and spot price

Objectives The first objective of the thesis is determining the form of time series data that would be suitable for conducting empirical research on coffee futures. The second objective is to conduct a hedonic regression model and to test the observed data for multiple linear regression. Finally, this paper would like to understand the relative importance of economic factors affecting coffee futures price. Summary Unit root test is conducted for 228 samples of Coffee “C” Futures and the independent variables: precipitation in Brazil and in Colombia, exchange rates USD/BRL and USD/COD, spot coffee price and coffee futures price of the previous month from January 1994 to December 2012. The Augmented Dicker-Fuller test suggests the first differencing method to remove unit root in time series data. Several tests for ensuring multiple regression assumptions are performed. The input variables could be said to be valid for conducting hedonic regression model. Conclusions The hedonic regression model reveals that 96% of coffee futures price could be explained by precipitation in Brazil and in Colombia, exchange rates USD/BRL and USD/COD, spot coffee price, coffee futures price of the previous month and dummy variable shock. Only spot price is of great significance at 95% confidence, while the others are not. Spot price also has the highest coefficient, while coefficients of other independent variables are relatively low

Assessing the Effects of Cold Storage Regimes of North American Bombus Queens: Long Live the Humble Queen

Bumble bees (Bombus) provide critical pollination services for wild plants and crops. They are generalist pollinators, and do not depend on one singular floral type. Native bumble bees are adapted to pollinating many native plants, such as blueberries, squash, and tomatoes. A critical component of bumble bee pollination in the greenhouse tomato industry is the domestication of commercially bred colonies. However, the domestication of Bombus is pretty early in its development, and not all aspects of the bumble bee life cycle is fully understood. This thesis addresses one of the major obstacles in domestication, which is successful mimicking of the overwintering phase of the lifecycle in captivity. Traditionally, captive Bombus queens are stored in constant low temperatures for a period of twelve weeks to mimic hibernation. However, there is a high mortality associated with this cold storage period, and we are unable to replicate wild overwintering durations in captive settings. To address the high mortality, we used three North American bumble bee species, stored queens in different cold storage regimes and assessed survivability. Here, we present results that there were other components to consider outside of thermal regimes such as initial weight, bumble bee colony age, and queen’s geographic origins. We found survivorship varied between wild queens (B. vosnesenskii and B. huntii) and commercial queens (B. impatiens). We saw with wild queens survival response was lower in a temperature cycling regime (FTR) compared to static thermal treatments (Control). However, in commercial B. impatiens, we saw the opposite outcome in survival, where survival response was higher in FTR. The variation in survival outcome may be reflective of their geographic differences. Results also suggested that high initial weight prior to cold storage determined survival and was linked to post hibernation lipids, which serves as an energy reserve. Despite the fact, lipids and weight are important to surviving captive cold storage, colony age influenced overwintering fitness. We have evidence that a queen’s initial weight prior to entering captive overwintering, survival, and colony’s age were inter-related. This study highlights that we should take a more comprehensive approach and take into account that overwintering treatments alone are not the silver bullet to addressing premature deaths in cold storage. Standardizing methods for Bombus cold storage will require careful consideration of the interplay between physiological variations, individual queen characteristics, and limitations among Bombus that emerge from seasonal colony aging

How is the review helpfulness evaluated?

A user-generated review that is perceived as helpful is valuable for both customer and the retailer, and that is why online markets such as Amazon.com collect public opinion on reviews that are perceived more helpful. Review platforms allow customers to vote for reviews they deem helpful. While prior literature has examined what drives the helpfulness of reviews, many of these studies have looked at drivers of perceived helpfulness of reviews in isolation. Using the lens of dual process theory, this research examines how consumers evaluate the helpfulness of a review. We propose a framework and provide empirical evidence for the evaluation of the review helpfulness process. We find that extreme reviews have a higher effect on review helpfulness compared to moderate reviews, and this effect is mediated by the depth and sentiment of the review content