A new model for the formation of microbial polygons in a coastal sabkha setting

The stratigraphic record of microbially induced sedimentary structures spans most of the depositional record. Today, microbes continue to generate, bind and modify sediments in a vast range of depositional environments. One of the most cited of these settings is the coastal microbial mat system of the Persian/Arabian Gulf. In this setting, an extensive zone of microbial mat polygons has previously been interpreted as resulting from desiccation‐related contraction during episodic drying. This study employs 15 years of field‐based monitoring of the interaction between environmental factors and the development and evolution of polygon morphologies to test the desiccation model in this setting. On the basis of these observations, a new model is proposed that accounts for the genesis and development of microbial polygons without the need for desiccation‐induced shrinkage. Conversely, the formation, development and erosion of microbial polygons is a direct result of the production of large amounts of organic matter in a healthy, yet spatially limited, microbial community. The recognition of microbial polygons has previously been applied as a diagnostic tool for the reconstruction of ancient depositional environments. The present study calls these interpretations into doubt. It is inferred that preservation of the microbial polygons as a recognizable form would be rare. Biological degradation and compaction will reduce polygons to produce the ‘wispy’ laminae that are a common feature of ancient sabkha lithofacies

How entrepreneurs deal with ethical challenges : an application of the Business Ethics Synergy Star Technique

Entrepreneurs typically live with the ever present threat of business failure arising from limited financial resources and aggressive competition in the marketplace. Under these circumstances, conflicting priorities arise and the entrepreneur is thus faced with certain dilemmas. In seeking to resolve these, entrepreneurs must often rely on their own judgment to determine ‘‘what is right’’. There is thus a need for a technique to assist them decide on a course of action when no precedent or obvious solution exists. This research paper examines how entrepreneurs experience and deal with these dilemmas. The research is based on interviews with seven entrepreneurs in established service-oriented ventures, which gave rise to 26 dilemmas. These dilemmas were analyzed by making use of the Synergy Star technique, which is introduced here as a tool that is useful in defining any dilemma, isolating the ethical component, and resolving the dilemma in a way that is congruent with the entrepreneur’s personal world-view

Planning drinking water for airplanes

The management of the Dutch national airline company KLM intends to bring a sufficient amount of water on board of all flights to fulfill customer’s demand. On the other hand, the surplus of water after a flight should be kept to a minimum to reduce fuel costs. The service to passengers is measured with a service level. The objective of this research is to develop models, which can be used to minimize the amount of water on board of flights such that a predefined service level is met. The difficulty that has to be overcome is the fact that most of the available data of water consumption on flights are rounded off to the nearest eighth of the water tank. For wide-body aircrafts this rounding may correspond to about two hundred litres of water. Part of the problem was also to define a good service level. The use of a service level as a model parameter would give KLM a better control of the water surplus. The available data have been analyzed to examine which aspects we had to take into consideration. Next, a general framework has been developed in which the service level has been defined as a Quality of Service for each flight: The probability that a sufficient amount of water is available on a given flight leg. Three approaches will be proposed to find a probability distribution function for the total water consumption on a flight. The first approach tries to fit a distribution for the water consumption based on the available data, without any assumptions on the underlying shape of the distribution. The second approach assumes normality for the total water consumption on a flight and the third approach uses a binomial distribution. All methods are validated and numerically illustrated. We recommend KLM to use the second approach, where the first approach can be used to determine an upper bound on the water level

Schwann cell to axon transfer of ribosomes: toward a novel understanding of the role of glia in the nervous system

Schwann cells play pivotal roles in the development and maintenance of the peripheral nervous system. Here, we show that intact sciatic nerve axons of mice contain a small population of ribosomes, which increases by several orders of magnitude when axons are desomatized (severed from their cell bodies). We furthermore demonstrate, using the Wallerian degeneration slow mouse as a model, that Schwann cells transfer polyribosomes to desomatized axons. These data indicate that Schwann cells have the propensity to control axonal protein synthesis by supplying ribosomes on local basis. Copyright © 2008 Society for Neuroscience

NLRP2 controls age-associated maternal fertility

Nucleotide-binding domain and leucine-rich repeat (NLR) proteins are well-known for their key roles in the immune system. Ectopically expressed NLRP2 in immortalized cell lines assembles an inflammasome and inhibits activation of the proinflammatory transcription factor NF-kappa B, but the physiological roles of NLRP2 are unknown. Here, we show that Nlrp2-deficient mice were born with expected Mendelian ratios and that Nlrp2 was dispensable for innate and adaptive immunity. The observation that Nlrp2 was exclusively expressed in oocytes led us to explore the role of Nlrp2 in parthenogenetic activation of oocytes. Remarkably, unlike oocytes of young adult Nlrp2-deficient mice, activated oocytes of mature adult mice developed slower and largely failed to reach the blastocyst stage. In agreement, we noted strikingly declining reproductive rates in vivo with progressing age of female Nlrp2-deficient mice. This work identifies Nlrp2 as a critical regulator of oocyte quality and suggests that NLRP2 variants with reduced activity may contribute to maternal age-associated fertility loss in humans

La forêt domaniale de Cadarache, compte-rendu de la tournée sur le terrain

La tournée de l'Association Forêt Méditerranéenne sur le terrain a été consacrée à une visite de la forêt domaniale de Cadarache. Aprés une présentation et un historique, une visite de 3 sites a eu lieu où a pu être abordée la sylviculture du chêne à partir de trois exemples concrets : le traitement en taillis simple, la conversion en futaie sur souche, la plantation de chênes truffiers

Optimizing Production of Xylindein by Chlorociboria sp. and its Potential for Use with Nanocellulose

Fungi from the genus Chlorociboria are known for their production of the blue-green quinonic pigment xylindein. Extracted xylindein has been the subject of investigations ranging from fabric dying to use a coloring agent in paint, and shows potential as an organic semiconductor in organic photovoltaics (OPVs) and other technologies. However, the pigment is known to form an amorphous layer when applied, which likely hinders its semiconductive properties. This research investigated if the renewably sourced material nanocellulose could provide a scaffold for the pigment, allowing for smooth film formation. It was found that xylindein applied to different forms of nanocellulose exhibited variations in morphology, however no smooth continuous pigment deposition was seen. In addition, methods of Chlorociboria growth were compared to identify conditions yielding highest pigment production. Pigment production was also compared across species and strains. It was found that liquid shaking cultures produced pigment in five weeks that was equivalent to two to three months of growth using previous methods. In addition, while there was variation between Chlorociboria cultures, strain made more of a difference than species and all cultures showed equivalent growth after five weeks. This improvement in growth methodology allows for production of quantities of pigment that could not previously be obtained through laboratory culture. This amount of pigment could permit investigations into methods of purification that will improve semiconductivity, and improve feasibility of industrial scale up. Use of xylindein as an organic semiconductor in OPVs could allow for sustainable energy generation, providing a renewable alternative to traditional technologies based on silicon and other inorganics

Demographics and Functional Outcome of Toe Fractures

Toe fractures are common; however, there are few data on demographics and functional outcome. We studied outcomes in 339 consecutive patients with toe fractures treated between January 2006 and September 2008. Two hundred and sixty-four patients, aged 16 to 75, were mailed an outcome questionnaire, and overall subjective satisfaction with the outcome of treatment was measured using a visual analog scale (VAS). Most frequently affected were the first (38%) and fifth (30%) toes, and most (75.6%) of the fractures were caused by stubbing or crush injury. More than 95% of the fractures were displaced less than 2 mm, and all of the fractures were treated conservatively. The questionnaire was returned by 141 (53%) patients with a median follow-up of 27 months. Respondents were female in 57.4% of cases and had a median age of 45 years. The median AOFAS score was 100 (P25, P75= 93,100) points; the median VAS was 10 (P25, P75= 8, 10) points. Univariate regression analysis revealed no statistically significant associations between outcome and the particular toe or phalanx involved, number of fractured toes, fracture type and location, articular involvement, gender, age, body mass index, smoking habits, and the presence of diabetes mellitus. Satisfaction VAS was dependent on age (P = .047) and gender (P = .049) in the multivariate analysis. The AOFAS midfoot score was not influenced by any of the covariates. This is the first epidemiological investigation using 2 outcome-scoring systems to determine function and satisfaction following treatment of toe fractures

Integration of professional judgement and decision-making in high-level adventure sports coaching practice

This study examined the integration of professional judgement and decision-making processes in adventure sports coaching. The study utilised a thematic analysis approach to investigate the decision-making practices of a sample of high-level adventure sports coaches over a series of sessions. Results revealed that, in order to make judgements and decisions in practice, expert coaches employ a range of practical and pedagogic management strategies to create and opportunistically use time for decision-making. These approaches include span of control and time management strategies to facilitate the decision-making process regarding risk management, venue selection, aims, objectives, session content, and differentiation of the coaching process. The implication for coaches, coach education, and accreditation is the recognition and training of the approaches that“create time” for the judgements in practice, namely“creating space to think”. The paper concludes by offering a template for a more expertise-focused progression in adventure sports coachin