Arctic Ocean evidence for late Quaternary initiation of northern Eurasian ice sheets

A high-resolution multiparameter stratigraphy allows the identification of late Quaternary glacial and interglacial cycles in a central Arctic Ocean sediment core. Distinct sandy layers in the upper part of the otherwise fine-grained sediment core from the Lomonosov Ridge (lat 87.5°N) correlate to four major glacials since ca. 0.7 Ma. The composition of these ice-rafted terrigenous sediments points to a glaciated northern Siberia as the main source. In contrast, lithic carbonates derived from North America are also present in older sediments and indicate a northern North American glaciation since at least 2.8 Ma. We conclude that large-scale northern Siberian glaciation began much later than other Northern Hemisphere ice sheets

Arctic Ocean evidence for late Quaternary initiation of northern Eurasian ice sheets

A high-resolution multiparameter stratigraphy allows the identification of late Quaternary glacial and interglacial cycles in a central Arctic Ocean sediment core. Distinct sandy layers in the upper part of the otherwise fine-grained sediment core from the Lomonosov Ridge (lat 87.5°N) correlate to four major glacials since ca. 0.7 Ma. The composition of these ice-rafted terrigenous sediments points to a glaciated northern Siberia as the main source. In contrast, lithic carbonates derived from North America are also present in older sediments and indicate a northern North American glaciation since at least 2.8 Ma. We conclude that large-scale northern Siberian glaciation began much later than other Northern Hemisphere ice sheets

Addressing Challenges for Informal Learning in Networks of Organizations

Current trends in information technology (IT) like social technologies and mobile devices lead to new opportunities for informal learning at the workplace. This is particularly true for physical workplace settings, in which the need to informally learn steadily increases. However, these current developments also lead to new challenges for informal workplace learning. Small and medium sized enterprises with their limited resources are overwhelmed and cannot address these challenges. Here, networks of organizations come into play. Literature states if networks provide IT capabilities for their members, the absorptive capacity of them can be increased. However, there is no research on how networks can design IT capabilities for their members to facilitate informal learning. In this paper, we are first identifying the challenges for informal learning in networks before discussing which IT capabilities networks should enhance to address these challenges to facilitate informal learning. Thus, we led 53 interviews in ten networks to investigate the challenges of informal learning in networks and the prospective IT support. Finally, we present the interview results and reflect the identified challenges and proposed solutions in light of the literature. These findings are put into a model outlining the role of IT capa-bilities enhanced by networks

Sniffin’ Sticks and Olfactometer-Based Odor Thresholds for n-Butanol: Correspondence and Validity for Indoor Air Scenarios

Threshold assessments for the reference odorant n-butanol are an integral part of various research, clinical, and environmental sensory testing procedures. However, the practical significance of a high or low threshold for n-butanol beyond a particular testing environment and procedure are often unclear. Therefore, this study aimed to determine between-method correlations and to investigate the association between the n-butanol threshold and perceptual/behavioral odor effects in natural breathing scenarios in 35 healthy adults. The thresholds for n-butanol derived from the Sniffin’ Sticks test and determined by the ascending limit dynamic dilution olfactometry procedure were significantly correlated (∣r∣ = 0.47). However, only the thresholds determined by olfactometry were significantly correlated to the odor detection of n-butanol in an exposure lab. Moreover, participants with a higher sensitivity for n-butanol in the olfactometer-based assessment rated ammonia, during a 75 min exposure, to be more unpleasant and showed better performance in a simultaneous 3-back task than participants with lower sensitivity. The results of this study suggest that beyond the strict parameters of a certain psychophysical procedure, the threshold for n-butanol can be a meaningful indicator of odor detection and effects in some cases

A short-term inhalation study to assess the reversibility of sensory irritation in human volunteers

Sensory irritation is an acute adverse effect caused by chemicals that stimulate chemoreceptors of the upper respiratory tract or the mucous membranes of the outer eye. The avoidance of this end point is of uttermost importance in regulatory toxicology. In this study, repeated exposures to ethyl acrylate were analyzed to investigate possible carryover effects from day to day for different markers of sensory irritation. Thirty healthy subjects were exposed for 4 h on five subsequent days to ethyl acrylate at concentrations permitted by the German occupational exposure limit at the time of study. Ratings of eye irritation as well as eye blinking frequencies indicate the elicitation of sensory irritation. These markers of sensory irritation showed a distinct time course on every single day. However, cumulative carryover effects could not be identified across the week for any marker. The rhinological and biochemical markers could not reveal hints for more pronounced sensory irritation. Neither increased markers of neurogenic inflammation nor markers of immune response could be identified. Furthermore, the performance on neurobehavioral tests was not affected by ethyl acrylate and despite the strong odor of ethyl acrylate the participants improved their performances from day to day. While the affected physiological marker, the increased eye blinking frequency stays roughly on the same level across the week, subjective markers like perception of eye irritation decrease slightly from day to day though the temporal pattern of, i.e., eye irritation perception stays the same on each day. A hypothetical model of eye irritation time course derived from PK/PD modeling of the rabbit eye could explain the within-day time course of eye irritation ratings repeatedly found in this study more precisely

Lung function reference values in different German populations

SummaryBackgroundSpirometry is a frequently performed lung function test and an important tool in medical surveillance examinations of pulmonary diseases. The interpretation of lung function relies on the comparison to reference values derived from a healthy population.The study aim was to compare the lung function data of three representative population-based German studies (Study of Health in Pomerania [SHIP-1], Cooperative Health Research in the Region of Augsburg [KORA-S3] and European Community Respiratory Health Survey Erfurt [ECRHS-I Erfurt]) with existing European spirometry reference values and to establish a new set of comprehensive German prediction equations.MethodsSpirometry was performed in 4133 participants of three population-based surveys using almost identical standardised methods. Current and former smokers, subjects with cardiopulmonary disorders or on medication with potential influence on lung function were excluded. Sex specific prediction equations were established by quantile regression analyses. Comparison was performed to existing European reference values.ResultsThe healthy reference sample consisted of 1302 (516 male) individuals, aged 20–80 years. Sex specific comprehensive prediction equations adjusted for age and height are provided. Significant differences were found in comparison to previous studies with pronounced lower values of the current population if applying historic prediction equations.ConclusionThe results contribute to the interpretation of lung function examination in providing a comprehensive set of spirometry reference values obtained in a large number of healthy volunteers. Whereas the differences in between the investigated studies are negligible, striking divergence was detected in comparison to historic and recent European spirometry prediction values