Highly sensitive multichannel spectrometer for subpicosecond spectroscopy in the midinfrared

A spectrometer system is presented for time-resolved probing in the midinfrared between 5 and 11 /tLmw ith a temporal resolution of better than 400 fs. Multichannel detection with HgCdTe detector arrays consisting of ten elements in combination with a high repetition rate permits one to record weak absorbance changes with an accuracy of 0.1 mOD

On the trophic fate of Phaeocystis pouchetii: VII. Sterols and fatty acids reveal sedimentation of Phaocystis-derived organic matter via krill fecal strings

As part of a joint project on the fate of phytoplankton in Balsfjorden in Northern Norway, we investigated the trophic fate and sedimentation potential of Phaeocystis pouchetii by tracing the transition of biomarker patterns from a phytoplankton bloom to sediment traps and during a gut passage experiment. The phytoplankton biomass during the spring bloom 1996 was dominated by colonial P. pouchetii (ca. 85 %) and four members of the diatom family Thalassiosiraceae (ca. 10%). Particulate organic carbon in sediment traps largely consisted of fecal material from the Arctic krill Thysanoessa sp.. Sterol and fatty acid biomarker patterns in the phytoplankton bloom could be reproduced by combining the individual biomarker patterns of the isolated phytoplankters P. pouchetii and Thalassiosira decipiens in a ratio of ca. 75:25. In a laboratory experiment, Arctic krill (Thysanoessa raschii) fed with similar efficiency on Phaeocystis colonies and the Thalassiosiraceae. During gut passage, the abundance of Thalassiosiraceae biomarkers in fecal strings increased relative to Phaeocystis biomarkers, while biomarkers from krill became dominant. This transition of biomarker patterns due to gut passage in T. raschii closely resembled the biomarker transition from the surface bloom to material in sediment traps at 40-170 m depth, which was mainly composed of krill fecal strings. We conclude that krill grazed efficiently on Phaeocystis colonies in Balsfjorden, and caused sedimentation of Phaeocystis-derived organic matter below the euphotic zone via fecal strings. Hence, both transfer to higher trophic levels and sedimentation of Phaeocystis-derived organic matter can be more effective than commonly believed

Nonequilibrium plasmons with gain in graphene

Graphene supports strongly confined transverse-magnetic sheet plasmons whose spectral characteristics depend on the energetic distribution of Dirac particles. The question arises whether plasmons can become amplified when graphene is pumped into a state of inversion. In establishing a theory for the dynamic non-equilibrium polarizability, we are able to determine the exact complex-frequency plasmon dispersion of photo-inverted graphene and study the impact of doping, collision loss, and temperature on the plasmon gain. We calculate the spontaneous emission spectra and carrier recombination rates self-consistently and compare the results with approximations based on Fermi's golden rule. Our results show that amplification of plasmons is possible under realistic conditions but inevitably competes with ultrafast spontaneous emission, which for intrinsic graphene, is a factor 5 faster than previously estimated. This work casts new light on the nature of non-equilibrium plasmons and may aid the experimental realization of active plasmonic devices based on graphene.Comment: 17 pages, 7 figures, published in PR

Consumer Willingness-To-Pay for Different Organic Certification Logos in Turkey

Using data from focus group discussions with consumers and a choice experimentconducted in some of Turkey’s major cities, this study investigates whetherTurkish consumers prefer certain organic labelling schemes over others attemptsand to elicit their willingness to pay (WTP) for different organic certificationlogos. Although the level of awareness regarding organic certification logos waslow, consumers’ perceptions of the logos were generally positive. The results ofthe random parameter logit models indicated a positive WTP for the presence ofone of the three tested certification body logos in addition to the mandatorygovernmental logo. Given the low level of certification logo awareness, theconclusion is that both purchasing decisions and perceptions regarding logoswere affected by subjective criteria. Both the government and certification bodiesshould develop measures to increase consumer awareness of their logos and formconsumer perceptions and attitudes regarding the quality of the certificationimplied by the logo

Factors influencing the perception of organic certification logos in Turkey

Consumers’ perceptions on organic certification logos and the factors influencing these perceptions were explored. Data from surveys conducted in major cities of Turkey revealed that organic food consumers had little knowledge about logos, although the declared level of trust in organic logos was high. According to ordered logit models, consumer’s perceptions on organic certification logos were influenced by purchasing frequency and weight of organic foods in total food consumption. Dummy variables representing additional private certification company logos as well were generally found to have a significant effect on logo perception. This result suggests that consumers’ attitudes towards these logos and towards the governmental logo are not the same. Female and older people were more sceptical about the trustworthiness of the logos. While the credibility of the logos and the standards and control systems underlying the logos increased as frequency of purchasing organic food increased, those consumers who prefer organic open markets for buying organic food were hesitant to trust the credibility of the organic certification logos. The mandatory governmental logo and the underlying standards are trusted more than the private company logos. However, the difference of the attitudes toward logos decreases when the control system is in question. When a comparison between perceptions towards labels including different additional certification companies’ logos is made, the additional logo was found to affect the stated preferences more negatively when the companies were foreign. Enhanced interest and trust in the organic certification logos among consumers would foment the development of the organic sector, and the findings of this paper serve as an input for the achievement of this aim

Educating young consumers through debate on global issues: a summer experience with the United Nations Foundation

Sponsored by the Marjorie J. and Richard L.D. Morse Family and Community Public Policy ScholarshipCitation: Hamm, M. M. (2008). Educating young consumers through debate on global issues: a summer experience with the United Nations Foundation. Unpublished manuscript, Kansas State University, Manhattan, KS.The People’s Speak’s foremost initiative in 2007-2008 was the Global Debates competition. In a partnership with the National Forensic League (NFL) and the International Debate Education Association (IDEA), the Global Debates competition provided two debate topics (one in October, the other in March) centered around climate change. High school students and debate teams from domestic and international schools had the opportunity to create public debates using the provided debate topics. In addition to hosting a public debate, schools were challenged to win a trip to the United Nations for the Youth Leadership Summit on climate change by completing a variety of activities including sending photos from the event, writing blog entries about the debate topic, receiving press, and inviting elected officials to the debate. The Youth Leadership Summit was the culminating event of all the hard work that these high school students had put in through the 2007-2008 year. The summit was held July 17-19 in New York City with over 180 students from 9 countries in attendance. Planning and execution of the Youth Leadership Summit was the main focus of my summer internship with The People Speak

Predicting Kidding Date Using Prepartum Milk Calcium Concentrations and Comparing Kid Growth to Colostrum Quality in Goats

Goats have an ancient history with humankind and are used as a red meat source around the world. This provides an opportunity in Arkansas agriculture. There is a gap in goat research which facilitated the conception of the study’s objectives to determine whether prepartum milk in goats showed a rise in calcium levels within 24 to 48 hours of kidding and to ascertain whether an increased colostrum density is indicative of increased weight gain in kids. Eleven does were bred out of season and monitored for mammary development. Then, 5 to 15 mL of prepartum milk were collected, and the calcium content was measured using a Chemetrics K-1700 system. Post-partum, a 20 mL sample of colostrum was collected and the density was tested using an Equine Colostrometer, antifreeze tester, and a Refractometer. Each kid was also weighed at birth, 30, 60, 90, and 120 days of age using a Premier 1110# scale. The weight was adjusted for age of dam, sex of kid, and birth type/rearing. The relationship between adjusted weights and colostrum quality and the relationship between calcium levels 24 and 48 hours prior to kidding with calcium levels at birth were analyzed using correlation and regression procedures. There was a negative correlation between the adjusted weights and colostrum quality; however, the relationship was not significant (P \u3e 0.05). Positive correlations between calcium levels at 24 and 48 hours prior to kidding and at birth were not significant (P \u3e 0.05). Moreover, the colostrum quality did not have an impact statistically on kid growth, and there was no significant rise in the calcium concentration of prepartum milk samples that could be used to estimate the time of parturition

Intramural duodenal hematoma: clinical course and imaging findings

Background: Intramural duodenal hematoma is a rare condition. Different imaging modalities are at hand for diagnosis. Purpose: To identify patients with intramural duodenal hematoma and report imaging findings and clinical courses. Material and Methods: Typical imaging patterns using ultrasound, computed tomography, and magnetic resonance imaging were carried out on 10 patients. Results: The mean patient age was 7.5 years. The average disease duration was 13 months. Clinical signs of improvement were observed within 16 days. Residues were still detectable at long-term follow-up. Conclusion: For patients with intramural duodenal wall hematoma, diagnosis should be considered early. Typical imaging findings should be known to ensure optimal treatment