New climate change scenarios for the Netherlands.

A new set of climate change scenarios for 2050 for the Netherlands was produced recently. The scenarios span a wide range of possible future climate conditions, and include climate variables that are of interest to a broad user community. The scenario values are constructed by combining output from an ensemble of recent General Climate Model (GCM) simulations, Regional Climate Model (RCM) output, meteorological observations and a touch of expert judgment. For temperature, precipitation, potential evaporation and wind four scenarios are constructed, encompassing ranges of both global mean temperature rise in 2050 and the strength of the response of the dominant atmospheric circulation in the area of interest to global warming. For this particular area, wintertime precipitation is seen to increase between 3.5 and 7% per degree global warming, but mean summertime precipitation shows opposite signs depending on the assumed response of the circulation regime. Annual maximum daily mean wind speed shows small changes compared to the observed (natural) variability of this variable. Sea level rise in the North Sea in 2100 ranges between 35 and 85 cm. Preliminary assessment of the impact of the new scenarios on water management and coastal defence policies indicate that particularly dry summer scenarios and increased intensity of extreme daily precipitation deserves additional attention in the near future.     

An efficient HARQ scheme for applications in multicast communication systems

This paper deals with the performance evaluation and optimization of an efficient hybrid automatic repeat request (HARQ) scheme suitable for applications delivered over lossy multicast communication channels. In particular, different from previously investigated strategies, this paper proposes a modified HARQ scheme based on the symbol combining principle (MHARQ‐SC) where multiple copies of a same packet are consecutively transmitted at each transmission opportunity. By considering as the performance metrics, the mean packet delivery delay, and the energy consumption per information packet, this paper presents suitable performance evaluation and optimization strategies tailored for multicast communications. For the sake of comparisons, it has been also analyzed, under the same operational conditions, the performance of different HARQ schemes optimized for multicast communications. Numerical results have been provided to validate the proposed performance evaluation and optimization approaches in the case of the MHARQ‐SC scheme. An important result devised here is that the reported analytical results clearly highlight the performance gain of the proposed strategy in comparison with all the other considered alternatives. Copyright © 2013 John Wiley & Sons, Ltd.     

Functional study of the rat cortical microcircuitry with voltage-sensitive dye imaging of neocortical slices

The computations performed within cortex are likely to be determined by its internal dynamics in addition to its pattern of afferent input. As a step toward characterizing these dynamics, we have imaged electrical activity in slices from rat primary visual cortex stained with the voltage-sensitive dye di-4-ANEPPS. In response to electrical stimulation two fluorescence signals of similar maximum amplitude are elicited, (i) A fast signal that peaks in a few milliseconds, is dependent on membrane voltage, and has a significant presynaptic component. This signal can be used to image electrical activity ratiometrically. (ii) A slow signal that peaks a few seconds after stimulation, does not reflect voltage changes, and may originate from changes in scattering properties of the slice and from interactions of the dye with the cells. The spatial pattern of fast signals obtained in response to focal stimulation of coronal slices is consistent with known interlaminar projection patterns. In tangential slices, imaging of fast signals reveals clustered horizontal responses. Finally, imaging of fast signals during epileptiform activation of the disinhibited circuit reveals propagating responses, without evidence for modular activation.     

Measured versus simulated transient disturbances induced on asystem harness

The increasing complexity of electronic payloads on satellites and aircraft has resulted in an increase in electromagnetic compatibility (EMC) test campaign costs and duration. Affordable simulation tools can help system engineers to reduce costs and prevent damage during tests. A method of moments (MOM) based simulation tool for the analysis of electrostatic discharge (ESD) interactions with systems has been assessed. Comparisons between experimental and simulated results are reported together with the adopted setup modeling philosophy. The results showed a very good performance of the simulation tool and the need to characterize and include in the computation the experimental current probe model     

Small cell carcinoma of gallbladder: report of two cases

Extrapulmonary small cell carcinoma has been reported from multiple sites, including the gallbladder. Small cell carcinoma of the gallbladder is a very rare tumor, found usually in elderly women and associated with cholelithiasis. It carries a grave prognosis, metastasizing early and causing death shortly after diagnosis. Treatment of metastatic disease with two different chemotherapeutic regimens has been shown to improve survival. To the best of our knowledge, this tumor has not been previously reported in a black individual, or in any subject less than 49 yr or more than 79 yr old. We report two cases: one is the first black and youngest reported case. The second is the oldest person reported with this rare malignancy. Radiological studies such as ultrasound and CT scan were useful in evaluating tumor spread and follow-up.     

Conformational stability of muscle acylphosphatase: the role of temperature, denaturant concentration, and pH

The conformational stability (delta G) of muscle acylphosphatase, a small alpha/beta globular protein, has been determined as a function of temperature, urea concentration, and pH. A combination of thermally induced and urea-induced unfolding, monitored by far-UV circular dichroism, was used to define the conformational stability over a wide range of temperature. Through analysis of all these data, the heat capacity change upon unfolding (delta Cp) could be estimated, allowing the determination of the temperature dependence of the main thermodynamic functions (delta G, delta H, delta S). Thermal unfolding in the presence of urea made it possible to extend such thermodynamic analysis to examine these parameters as a function of urea concentration. The results indicate that acylphosphatase is a relatively unstable protein with a delta G(H2O) of 22 +/- 1 kJ mol-1 at pH 7 and 25 degrees C. The midpoints of both thermal and chemical denaturation are also relatively low. Urea denaturation curves over the pH range 2-12 have allowed the pH dependence of delta G to be determined and indicate that the maximum stability of the protein occurs near pH 5.5. While the dependence of delta G on urea (the m value) does not vary with temperature, a significant increase has been found at low pH values, suggesting that the overall dimensions of the unfolded state are significantly affected by the number of charges within the polypeptide chain. The comparison of these data with those from other small proteins indicates that the pattern of conformational stability is defined by individual sequences and not by the overall structural fold.     

Turbo soft combining hybrid ARQ techniques: Theory and application to 3G wireless networks

This paper deals with the application of Hybrid Automatic Repeat reQuest (h-arq) techniques to allow reliable data communications in wireless 3G networks. Basically, retransmission of coded data is endowed with soft combining schemes applied, respectively, to packet replicas, or to decoding algorithm outputs. In particular, the proposed coding scheme takes advantage of error correction capabilities of the turbo codes, while the combining algorithm follows the diversity approach. The performance of the proposedh-arq schemes has been derived by means of a suitable analytical approach and numerical simulations in the case of a typical umts environment. The results highlight the good behavior of the proposed scheme in term of error rate, throughput, packet delivery delay and power reduction.     

A staging system for forelimb regeneration in the axolotl, Ambystoma mexicanum

A staging system has been devised for normal regeneration from the upper arm in the mature axolotl. It consists of seven externally definable stages: (1) Wound healing (WH): (2) Dedifferentiation (DD); (3) Early bud (EB); (4) Medium bud (MB); (5) Late bud (LB); (6) Palette (Pal), and (7) Digital outgrowth (DO). Serial histological sections of 38 regenerating limbs were used to correlate gross stages with microscopic events in the regenerative process.