Modification of light utilization for skeletal growth by water flow in the scleractinian coral Galaxea fascicularis

In this study, we tested the hypothesis that the importance of water flow for skeletal growth (rate) becomes higher with increasing irradiance levels (i.e. a synergistic effect) and that such effect is mediated by a water flow modulated effect on net photosynthesis. Four series of nine nubbins of G. fascicularis were grown at either high (600 µE m-2 s-1) or intermediate (300 µE m-2 s-1) irradiance in combination with either high (15–25 cm s-1) or low (5–10 cm s-1) flow. Growth was measured as buoyant weight and surface area. Photosynthetic rates were measured at each coral’s specific experimental irradiance and flow speed. Additionally, the instantaneous effect of water flow on net photosynthetic rate was determined in short-term incubations in a respirometric flowcell. A significant interaction was found between irradiance and water flow for the increase in buoyant weight, the increase in surface area, and specific skeletal growth rate, indicating that flow velocity becomes more important for coral growth with increasing irradiance levels. Enhancement of coral growth with increasing water flow can be explained by increased net photosynthetic rates. Additionally, the need for costly photo-protective mechanisms at low flow regimes could explain the differences in growth with flow

Distribution of glycan motifs at the surface of midgut cells in the cotton leafworm (Spodoptera littoralis) demonstrated by lectin binding

Glycans are involved in many biological phenomena, including signal transduction, cell adhesion, immune response or differentiation. Although a few papers have reported on the role of glycans in the development and proper functioning of the insect midgut, no data are available regarding the localization of the glycan structures on the surface of the cells in the gut of insects. In this paper, we analyzed the spatial distribution of glycans present on the surface of the midgut cells in larvae of the cotton leafworm Spodoptera littoralis, an important agricultural pest insect worldwide. For this purpose, we established primary midgut cell cultures, probed these individual cells that are freely suspended in liquid medium with a selection of seven fluorescently labeled lectins covering a range of different carbohydrate binding specificities [mannose oligomers (GNA and HHA), GalNAc/Gal (RSA and SSA), GlcNAc (WGA and Nictaba) and Neu5Ac(alpha-2,6)Gal/GalNAc (SNA-I)], and visualized the interaction of these lectins with the different zones of the midgut cells using confocal microscopy. Our analysis focused on the typical differentiated columnar cells with a microvillar brush border at their apical side, which are dominantly present in the Lepidopteran midgut and function in food digestion and absorption, and as well as on the undifferentiated stem cells that are important for midgut development and repair. Confocal microscopy analyses showed that the GalNAc/Gal-binding lectins SSA and RSA and the terminal GlcNAc-recognizing WGA bound preferentially to the apical microvillar zone of the differentiated columnar cells as compared to the basolateral pole. The reverse result was observed for the mannose-binding lectins GNA and HHA, as well as Nictaba that binds preferentially to GlcNAc oligomers. Furthermore, differences in lectin binding to the basal and lateral zones of the cell membranes of the columnar cells were apparent. In the midgut stem cells. GNA and Nictaba bound more strongly to the membrane of these undifferentiated cells compared to the microvillar pole of the columnar cells, while SSA, HHA, WGA, and SNA-I showed stronger binding to the microvilli. Our results indicated that polarization of the midgut cells is also reflected by a specific distribution of glycans, especially between the basal and microvillar pole. The data are discussed in relation to the functioning and development of the insect midgut

Using transfer entropy to study synaptic integration in Purkinje cells

Peer reviewe

Light intensity, photoperiod duration, daily light flux and coral growth of Galaxea fascicularis in an aquarium setting: a matter of photons?

Light is one of the most important abiotic factors influencing the (skeletal) growth of scleractinian corals. Light stimulates coral growth by the process of light-enhanced calcification, which is mediated by zooxanthellar photosynthesis. However, the quantity of light that is available for daily coral growth is not only determined by light intensity (i.e. irradiance), but also by photoperiod (i.e. the light duration time). Understanding and optimizing conditions for coral growth is essential for sustainable coral aquaculture. Therefore, in this study, the question was explored whether more light (i.e. more photons), presented either as irradiance or as light duration, would result in more growth. A series of nine genetically identical coral colonies of Galaxea fascicularis L. were cultured for a period of 18 weeks at different light duration times (8 hours 150 µE m-2 s-1:16 hours dark, 12 hours 150 µE m-2 s-1:12 hours dark, 16 hours 150 µE m-2 s-1:8 hours dark, 24 hours 150 µE m-2 s-1:0 hours dark) and different irradiance levels (8 hours 150 µE m-2 s-1:16 hours dark, 8 hours 225 µE m-2 s-1:16 hours dark and 8 hours 300 µE m-2 s-1:16 hours dark). Growth was determined every two weeks by measuring buoyant weight. Temperature, salinity and feeding levels were kept constant during the experiment. To detect possible acclimation of the corals to an increased light duration, rates of net photosynthesis and dark respiration were measured, hereby comparing coral colonies grown under an 8:16 hours light (150 µE m-2 s-1):dark cycle with corals grown under a 16:8 hours light (150 µE m-2 s-1):dark cycle. No increase in growth was detected with either increasing photoperiod or irradiance. Continuous lighting (24 hours 150 µE m-2 s-1:0 hours dark) resulted in immediate bleaching and the corals died after 14 weeks. Hourly photosynthetic rates were significantly reduced in the 16 hour light treatment compared to the 8 hour light treatment. As a result, daily net photosynthetic rates were not significantly different, which may explain the observed specific growth rates. Acclimation to photoperiod duration appeared neither to be mediated by changes in chlorophyll-a concentration nor zooxanthellae density. Based on the results of this study, we can conclude that the enhancing effect of light on coral growth is not only a matter of photons. Obviously, the availability of light was not limiting growth in these experiments and was probably in excess (i.e. stressful amounts). Other factors are discussed that play a role in determining growth rates and might explain our results

Similarities and differences of pumping conventional and self-compacting concrete

In Practice, Self-Compacting Concrete (SCC) is Considered as a Simple Extension of Conventional Vibrated Concrete (CVC) When Pumping is Concerned. the Same Equipment, Materials, Pumping Procedures and Guidelines Used for CVC Are Applied When Pumping SCC. on the Other Hand, It Has Been Clearly Shown that the Rheological Properties and the Mix Design of SCC Are Different Than CVC. Can the Same Pumping Principles Employed for CVC Be Applied for SCC? This Paper Compares the Some Published Results of Pumping of CVC with Those for SCC. a First Striking Difference between Pumping of CVC and SCC is the Flow Behaviour in the Pipes. the Flow of CVC is a Plug, Surrounded by a Lubricating Layer, While during the Flow of SCC, Part of the Concrete Volume itself is Sheared Inside the Pipe. as a Result, the Importance of Viscosity Increases in Case of SCC. Due to the Low Yield Stress of SCC, the Behaviour in Bends is Different, But Quite Complex to Study. Due to the Lower Content of Aggregate and Better Stability of SCC, as It is Less Prone to Internal Water Migration, Blocking is Estimated to Occur at Lower Frequency in Case of SCC. © RILEM 2010

A rolling-horizon quadratic-programming approach to the signal control problem in large-scale congested urban road networks

The paper investigates the efficiency of a recently developed signal control methodology, which offers a computationally feasible technique for real-time network-wide signal control in large-scale urban traffic networks and is applicable also under congested traffic conditions. In this methodology, the traffic flow process is modeled by use of the store-and-forward modeling paradigm, and the problem of network-wide signal control (including all constraints) is formulated as a quadratic-programming problem that aims at minimizing and balancing the link queues so as to minimize the risk of queue spillback. For the application of the proposed methodology in real time, the corresponding optimization algorithm is embedded in a rolling-horizon (model-predictive) control scheme. The control strategy’s efficiency and real-time feasibility is demonstrated and compared with the Linear-Quadratic approach taken by the signal control strategy TUC (Traffic-responsive Urban Control) as well as with optimized fixed-control settings via their simulation-based application to the road network of the city centre of Chania, Greece, under a number of different demand scenarios. The comparative evaluation is based on various criteria and tools including the recently proposed fundamental diagram for urban network traffic

Diagnosing overtraining in athletes using the two-bout exercise protocol

Objective: In this work, whether a two-bout exercise protocol can be used to make an objective, immediately available distinction between non-functional over reaching (NFO) and overtraining syndrome (OTS) was studied. Design: Underperforming athletes who were diagnosed with the suspicion of NFO or OTS were included in the study. Recovery of the athletes was monitored by a sports physician to retrospectively distinguish NFO from OTS. Setting: Sports medicine laboratory Participants: The protocol was started and completed by 10 underperforming athletes. NFO was retrospectively diagnosed in five athletes, and OTS was diagnosed in five athletes. Interventions: A two-bout maximal exercise protocol was used to measure physical performance and stressinduced hormonal reactions. Main outcome measurements: Exercise duration, heart rate and blood lactate concentration were measured at the end of both exercise tests. Venous concentrations cortisol, adrenocorticotrophic hormone (ACTH), prolactin and growth hormone were measured both before and after both exercise tests. Results: Maximal blood lactate concentration was lower in OTS compared with NFO, while resting concentrations of cortisol, ACTH and prolactin concentrations were higher. However, sensitivity of these measures was low. The ACTH and prolactin reactions to the second exercise bout were much higher in NFO athletes compared with OTS and showed the highest sensitivity for making the distinction. Conclusions: NFO might be distinguished from OTS based on ACTH and prolactin reactions to a two-bout exercise protocol. This protocol could be a useful tool for diagnosing NFO and OTS; however, more data should be collected before this test can be used as the gold standard

Estimation of Large-Scale Multi-Rate Systems ⋆

model predictive control and estimation of large-scal

An Agent-Based Approach to Self-Organized Production

The chapter describes the modeling of a material handling system with the production of individual units in a scheduled order. The units represent the agents in the model and are transported in the system which is abstracted as a directed graph. Since the hindrances of units on their path to the destination can lead to inefficiencies in the production, the blockages of units are to be reduced. Therefore, the units operate in the system by means of local interactions in the conveying elements and indirect interactions based on a measure of possible hindrances. If most of the units behave cooperatively ("socially"), the blockings in the system are reduced. A simulation based on the model shows the collective behavior of the units in the system. The transport processes in the simulation can be compared with the processes in a real plant, which gives conclusions about the consequencies for the production based on the superordinate planning.Comment: For related work see http://www.soms.ethz.c