Mitigating risk in ecommerce transactions: perceptions of information credibility and the role of user-generated ratings in product quality and purchase intention

Although extremely popular, electronic commerce environments often lack information that has traditionally served to ensure trust among exchange partners. Digital technologies, however, have created new forms of “electronic word-of-mouth,” which offer new potential for gathering credible information that guides consumer behaviors. We conducted a nationally representative survey and a focused experiment to assess how individuals perceive the credibility of online commercial information, particularly as compared to information available through more traditional channels, and to evaluate the specific aspects of ratings information that affect people’s attitudes toward ecommerce. Survey results show that consumers rely heavily on web-based information as compared to other channels, and that ratings information is critical in the evaluation of the credibility of online commercial information. Experimental results indicate that ratings are positively associated with perceptions of product quality and purchase intention, but that people attend to average product ratings, but not to the number of ratings or to the combination of the average and the number of ratings together. Thus suggests that in spite of valuing the web and ratings as sources of commercial information, people use ratings information suboptimally by potentially privileging small numbers of ratings that could be idiosyncratic. In addition, product quality is shown to mediate the relationship between user ratings and purchase intention. The practical and theoretical implications of these findings are considered for ecommerce scholars, consumers, and vendors.     

A mitotically unstable human dicentric Y chromosome in a male pseudohermaphrodite

A patient with a mitotically unstable dic(Y)(p11) chromosome is reported. Physical examination revealed a small penis with severe hypospadia, undescended testes, rudimetary vagina, uterus, left fallopian tube, and no stigmata of Turner syndrome. Longitudinal chromosome studies over a four-year period, including blood, skin, foreskin, and testicular tissue, revealed 45,X/46,X,dic(Y)(p11)/46,X,del(dic Y) mosaicism. The proportions of these cells varied in the different tissues, and only 45,X and 46,X,del(dic Y) were major cell lines in testicular tissue. Additional minor cell lines were present mainly in peripheral blood: 47,X,dicY,dicY; 47,X,dicY,del(dicY); and 47,X,del(dicY),del(DICY). Premature disjunction of one of the centromeres in a high percentage of the dicentric Y chromosomes in metaphase was observed by Q- and C-banding. Lymphocytes at anaphase and telophase showed lagging Y chromosomes, fragments, and nondisjunction. These observations indicate a high degree of mitotic instability and thus raise the question of the effect of premature centromeric disjunction on mitotic instability of dicentric chromosomes.     

Measurements and Analysis of Photochemical Oxidants and Trace Gases in the Rural Troposphere of the Southeast United States

Ambient concentrations of photochemical oxidants (O₃, PAN, HNO₃, H₂O₂) and various trace species including reactive nitrogen compounds as well as total NO_y were measured during June and early July 1992 at a rural site, SONIA, in the central Piedmont region of North Carolina, as a part of the Southern Oxidants Study. The measurements were made in an effort to provide a comprehensive understanding of tropospheric photochemistry in the rural Southeastern United States. NO_y, NO₂, and NO showed diurnal variations with maxima in the morning between 0600 and 0900 EST. The maximum NO_y, NO, and NO₂ concentrations reached were 14.5, 5.4, and 7.8 ppbv, respectively. The mean NO_y concentration was found to be 2.63 ± 1.72 ppbv (n = 819) with an average daily maximum of 3.6 ppbv. The mean concentrations of NO and NO₂ for the entire period of measurement were found to be 0.18 ± 0.37 ppbv (n = 794) and 1.31 ± 0.99 ppbv/(n = 769). H₂O₂, HNO₃, and PAN showed diurnal variation with maxima in the afternoon and minima at night. Mean concentrations were found to be 0.52 ± 0.36 ppbv (n = 312), 0.67 ± 0.33 ppbv (n = 250), and 0.41 ± 0.24 ppbv (n = 578). The NO_x/NO_y ratio was used as an indicator of the chemical age of airmasses and the ratio showed strong positive correlations with the photochemical oxidants HNO₃ (r = 0.76), PAN (r= 0.68), and O₃ (r = 0.79) measured at the site. The relationship between the accumulation rate of O₃ and the deviation from the photostationary state was examined based on the measured PSS constant obtained from the values of [O₃], [NO], and [NO₂] measured at the site.     

Effect of an interactive web-based instruction in the performance of undergraduate anatomy and physiology lab students

This study provides an understanding of how different interactive technology tools that are integrated into a Website can be used for teaching undergraduate human anatomy and physiology laboratory students. Technology tools refer to a Website that the authors created to teach the Cardiovascular System that includes dynamic tools such as the Pronunciation Corner and Spelling Bee, and an Interactive practice and test tool. The Cardiovascular System was chosen as the subject matter to modify based upon the results of a pilot study where students indicated difficulty in understanding this subject. In addition, a “Teacher Resources” tool on the Website allows any teacher to create their own Pronunciation Corner and Spelling Bee and use them for their classes. The statistical analyses showed that the experimental group students (who had access to the Website) took advantage of the technology tools provided and demonstrated significant improvement in their performance on the cardiovascular portion of the lab test.     

Mercury speciation in coal-fired power plant plumes observed at three surface sites in the southeastern U.S

Elemental Hg (Hg0), reactive gaseous Hg (RGM) and fine particulate Hg (Hgp) were measured intermittently at three sites in the southeastern U.S. from June 2001 through November 2004. Simultaneous measurements of SO2 and NOy were used to identify plumes from coal fired power plants (CFPPs). Emission signatures and back trajectories were used to identity specific CFPPs, and to compare observed (i.e., at the site) versus expected (i.e., at the stack) Hg speciation. Results for 41 precipitation-free plume events show that observed RGM:SO2 is substantially lower (by a factor of 2-4) than expected RGM:SO2. Hgp represented 2%, or less, of total-Hg in CFPP plumes, in general agreement with emission estimates. Results for 21 events, where both RGM and Hg0 could be estimated, show that total-Hg (i.e., RGM + Hg0) was essentially conserved from the point of emission to the site, and that Hg0 was the dominant form (average 84%). Emission estimates, based on coal analyses and the EPRI-ICR Hg speciation model, indicate that Hg0 should represent about 42% of Hg in the observed plumes. Possible explanations for these differences include, but are not limited to, in-plume reduction of RGM to Hg0, measurement error, errors in emission estimates, and depositional losses. Further work is needed to confirm these results and to determine if they apply to CFPPs in general, or the limited set of observed CFPPs.