An Empirical Study of Price Dispersion in Homogenous Goods Markets

This paper presents the results of an empirical study of price dispersion in homogeneous goods markets. Modern economic theory suggests that inevitable asymmetries of information in markets lead to an equilibrium in which price dispersion is present even when goods are perfectly homogenous. In this paper we present an empirical analysis in which we employ both cross-sectional and time-series data gathered directly from Pricegrabber.com, one of the most popular and comprehensive online shopping/price-comparison sites on the Internet. In particular our analysis focuses on (i) the effect that the number of firms offering a good has on price dispersion, (ii) the informational value to the consumer of using the Pricegrabber website, and (iii) the persistency of price dispersion over time.E-commerce, Internet marketing, Price dispersion, Signaling, Search Cost, Gatekeepers, Regression and other statistical techniques JEL Classification: L81, L86, L11

Determinants of Inter-Country Internet Diffusion Rates

This paper employs cross-sectional data from 100 countries to analyze the main determinants of inter-country Internet diffusion rates. We set up an empirical model based on strong theoretical foundations, in which we regress Internet usage on variables that capture social, economic and political differences between these countries. Our results support past findings that economic strength, infrastructure and knowledge of the English language positively affect Internet connectivity. In addition to these indicators, the openness of a country, tertiary enrollment, and income equality are found to also have a significant positive effect on Internet diffusion.internet, technological diffusion, inequality, education, English proficiency

The freshwater crayfish Austropotamobius pallipes in South Tyrol. Heritage species and bioindicator

Rapid decline of crayfish in European freshwaters and continuing threat necessitate integrated actions in conservation and management of native crayfish populations. Besides biological reasons (diseases, plague), the impact of toxic and harmful substances (fertilisers, herbicides) or wastewater effluents, habitat alteration or fragmentation have been responsible for their decline in some regions. The same is true for the region of South Tyrol, where compared to previous investigations, only 10 of a former total of 15 crayfish locations in the water bodies could be affirmed. Although two new populations of the non-indigenous Astacus astacus were detected, the native Austropotamobius pallipes continues to decline. While many investigations have focused accurately on causal coherences for the decline of native populations, the properties of crayfish facilitate to reverse the situation. In a few examples, the potential of Austropotamobius pallipes, the native crayfish in South Tyrol, as “surrogate species” for effective biological conservation is discussed. Given the various adequate attributes of freshwater crayfish as surrogate species (including indicator species, umbrella species and flagship species qualities), they may help to advance not only the crayfish situation itself but also freshwater ecosystem properties in general

Atmospheric chemistry of gas-phase polycyclic aromatic hydrocarbons: formation of atmospheric mutagens.

The atmospheric chemistry of the 2- to 4-ring polycyclic aromatic hydrocarbons (PAH), which exist mainly in the gas phase in the atmosphere, is discussed. The dominant loss process for the gas-phase PAH is by reaction with the hydroxyl radical, resulting in calculated lifetimes in the atmosphere of generally less than one day. The hydroxyl (OH) radical-initiated reactions and nitrate (NO3) radical-initiated reactions often lead to the formation of mutagenic nitro-PAH and other nitropolycyclic aromatic compounds, including nitrodibenzopyranones. These atmospheric reactions have a significant effect on ambient mutagenic activity, indicating that health risk assessments of combustion emissions should include atmospheric transformation products

Neurogenin 3-expressing progenitor cells in the gastrointestinal tract differentiate into both endocrine and non-endocrine cell types

AbstractMice deficient for the transcription factor neurogenin 3 (ngn3) fail to develop endocrine cells in the intestine and pancreas and show partial endocrine differentiation in the stomach. We expressed Cre recombinase under control of a ngn3 BAC to achieve high fidelity cell lineage tracing in vivo to determine whether endocrine cells in these organs differentiate from NGN3+ precursor cells. Our results indicate that all small intestinal enteroendocrine cells arise from ngn3-expressing cells and confirm that NGN3+ cells give rise to all pancreatic endocrine cells as noted previously. By examining mice at a developmental stage when all of the cell types in the stomach have differentiated, we have delineated region-associated differences in endocrine differentiation. A much smaller fraction of endocrine cells populating the acid-producing region of the stomach is derived from NGN3+ precursor in contrast to the antral–pyloric region. Unexpectedly, ngn3 is expressed in cells that adopt non-endocrine cell fates including significant fractions of goblet and Paneth cells in the intestine and a small number of duct and acinar cells in the pancreas. Rarely, ngn3 was expressed in pluripotent cells in intestinal crypts with resultant labeling of an entire crypt–villus unit. Thus, ngn3 expression occurs in mixed populations of immature cells that are not irreversibly committed to endocrine differentiation

Intestinal Neurod1 expression impairs paneth cell differentiation and promotes enteroendocrine lineage specification

Transcription factor Neurod1 is required for enteroendocrine progenitor differentiation and maturation. Several earlier studies indicated that ectopic expression of Neurod1 converted non- neuronal cells into neurons. However, the functional consequence of ectopic Neurod1 expression has not been examined in the GI tract, and it is not known whether Neurod1 can similarly switch cell fates in the intestine. We generated a mouse line that would enable us to conditionally express Neurod1 in intestinal epithelial cells at different stages of differentiation. Forced expression of Neurod1 throughout intestinal epithelium increased the number of EECs as well as the expression of EE specific transcription factors and hormones. Furthermore, we observed a substantial reduction of Paneth cell marker expression, although the expressions of enterocyte-, tuft- and goblet-cell specific markers are largely not affected. Our earlier study indicated that Neurog3+ progenitor cells give rise to not only EECs but also Goblet and Paneth cells. Here we show that the conditional expression of Neurod1 restricts Neurog3+ progenitors to adopt Paneth cell fate, and promotes more pronounced EE cell differentiation, while such effects are not seen in more differentiated Neurod1+ cells. Together, our data suggest that forced expression of Neurod1 programs intestinal epithelial cells more towards an EE cell fate at the expense of the Paneth cell lineage and the effect ceases as cells mature to EE cells

Value Conflict, Lack of Rewards, and Sense of Community as Psychosocial Risk Factors of Burnout in Communication Professionals (Press, Radio, and Television)

Journalists are at particular risk of work-related stress and burnout. The objective of this study is to describe and analyze the principal factors involved in the appearance of burnout in communication professionals, as well as the possible interactions between them and with self-reported health, and to observe whether the variables involved are the same in different types of environments. To achieve this objective, 292 participants answered the following measurement instruments: Demographic and labor datasheet; Maslach Burnout Inventory (MBI General survey); Areas of Worklife Scale (AWS); and General Health Questionnaire (GHQ -12). The results were the following: Emotional Exhaustion (EE) shows direct correlation and statistical significance with the other two burnout dimensions, Depersonalization (DP) and Personal Accomplishment (PA), also with health perception variables and inverse and statistical significance with the workload, control, rewards, community, fairness, and values. A multiple linear regression model shows workload and values as inverse EE predictors, which confirms a burnout process in which EE contributes as the main dimension in DP and is shown to be a precursor of PA, itself. When comparing different types of media, journalists who work in institutional press offices presented significantly lower scores in PA and higher in control, rewards, community, justice, and values. Therefore, further research should be carried out in order to analyze the protective role of these variables regarding PA and burnout

Burnout in the ICU : potential consequences for staff and patient well-being

Peer reviewedAuthor versio

Hypoxia and Hypoglycemia synergistically regulate mRNA stability

Ischemic events, common in many diseases, result from decreased blood flow and impaired delivery of oxygen and glucose to tissues of the body. While much is known about the cellular transcriptional response to ischemia, much less is known about the posttranscriptional response to oxygen and glucose deprivation. The goal of this project was to investigate one such posttranscriptional response, the regulation of mRNA stability. To that end, we have identified several novel ischemia-related mRNAs that are synergistically stabilized by oxygen and glucose deprivation including VEGF, MYC, MDM2, and CYR61. This increase in mRNA half-life requires the synergistic effects of both low oxygen (1%) as well as low glucose ( 1 g/L) conditions. Oxygen or glucose deprivation alone fails to initiate the response, as exposure to either high glucose (4 g/L) or normoxic conditions inhibits the response. Furthermore, in response to hypoxia/hypoglycemia, the identified mRNAs are released from the RNA binding protein KHSRP which likely contributes to their stabilization