Nutritional deficits during early development affect hippocampal structure and spatial memory later in life.

Development rates vary among individuals, often as a result of direct competition for food. Survival of young might depend on their learning abilities, but it remains unclear whether learning abilities are affected by nutrition during development. The authors demonstrated that compared with controls, 1-year-old Western scrub jays (Aphelocoma californica) that experienced nutritional deficits during early posthatching development had smaller hippocampi with fewer neurons and performed worse in a cache recovery task and in a spatial version of an associative learning task. In contrast, performance of nutritionally deprived birds was similar to that of controls in 2 color versions of an associative learning task. These findings suggest that nutritional deficits during early development have long-term consequences for hippocampal structure and spatial memory, which, in turn, are likely to have a strong impact on animals' future fitness (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration

Metallurgical and Materials Transactions B - The influence of filter surface chemistry on the filtration efficiency of cast aluminum alloys was evaluated for four different filter coating...     

Rapid reperfusion causes stress failure in ischemic rat lungs

OBJECTIVE: Rapid reperfusion may be injurious to the ischemic lung. Our aim was to confirm that slow reperfusion improves postischemic pulmonary function and to elucidate the ultrastructural changes associated with slow versus rapid reperfusion. METHODS. We used an ex vivo perfused rat lung transplant model to study the effect of slow versus rapid reperfusion on subsequent lung function and morphologic conditional. Functional assessment was performed in (1) fresh lung, slowly reperfused; (2) fresh lung, rapidly reperfused; (3) ischemic lung (4 hours at 22 degrees C), slowly reperfused; and (4) ischemic lung, rapidly reperfused. RESULTS: In group 4, the shunt fraction (P=.001), airway pressure (P=.001), and wet/dry ratio (P=.01) were significantly higher than in groups 1 through 3. Light and electron microscopy of slowly reperfused ischemic lungs (n=4) appeared normal. Rapidly reperfused ischemic lungs (n=4) demonstrated massive alveolar edema hemorrhage, and epithelial "blebbing" by light microscopy. Electron microscopy identified the blebbing as separation of the epithelial layer from an intact basement membrane by edema fluid. The epithelial layer was disrupted in numerous locations. Complete disruption of all layers of the blood-gas barrier was occasionally present. CONCLUSION: Rapid reperfusion of the ischemic lung is an important contributing factor to reperfusion lung injury resulting in mechanical stress failure of the alveolar/capillary barrier. Gradual reintroduction of blood flow to the ischemic lung improves oxygenation.     

Cost and Energy Effective Management of EAF with Flexible Charge Material Mix

Within the framework of the project FLEXCHARGE, performed within the RFCS steel research program, a team including research institutes and steel producers developed and tested in an industrial environment a methodology to effectively manage the EAF charged with variable materials. Statistical and deterministic methods were used together to determine yield and composition of different scrap types as well as the influence of the scrap mix on the off-gas emission and the slag composition. The paper summarizes the most relevant results obtained at four different EAF plants by applying the improved process control and by performing industrial trials for different steel grades. It also shows how the use of low quality scrap types in the charge mix has been maximized, considering the tramp element restrictions and scrap availability, yield as well as specific energy consumption.     

Advanced control strategy for a digital mass flow controller

Mass flow controllers are complex mechatronic devices, the design of which involves many techniques and skills in various scientific domains. Due to the slow response time of the sensors embedded in such devices, it is critically important to control gas flow variations in processes used in semiconductor industry. This paper shows how a digital controller for MFCs can be mathematically computed once the dynamic characteristics of the open-loop system have been identified. The proposed control method goes beyond prior art control methods as it explicitly takes into account the dynamics of the sensor, computes the digital controller appropriate to the order of the open-loop model and imposes a desired closed-loop transient response. The simulations performed and experimental results obtained with this new type of digital controller were very promising.     

UWB-based sensor networks for localization in mining environments

Wireless sensor networks (WSN) have attached a great attention in the last few years. WSN offer several advantages over the traditional sensor networks, such as elimination of costly wires, security and larger area coverage. In the last few years, there has been great interest commercial applications based on Ultra Wideband (UWB). It has potentially low complexity, low cost and an excellent time domain resolution which facilitates location and tracking applications. Therefore, UWB provide a good combination of high performance with low complexity for WSN applications. Localization has attracted considerable attention in many fields. Accurate estimation of an individual location can be a difficult task, producing ambiguous results particularly in harsh environment. In this paper, we focus on feasibility study (via simulation and measurements) of using UWB based-WNS as future solution for localization in underground mines.     

Size Effect on Properties of Varistors Made From Zinc Oxide Nanoparticles Through Low Temperature Spark Plasma Sintering

Conditions for the elaboration of nanostructured varistors by spark plasma sintering (SPS) are investigated, using 8‐nm zinc oxide nanoparticles synthesized following an organometallic approach. A binary system constituted of zinc oxide and bismuth oxide nanoparticles is used for this purpose. It is synthesized at room temperature in an organic solution through the hydrolysis of dicyclohexylzinc and bismuth acetate precursors. Sintering of this material is performed by SPS at various temperatures and dwell times. The determination of the microstructure and the chemical composition of the as‐prepared ceramics are based on scanning electron microscopy and X‐ray diffraction analysis. The nonlinear electrical characteristics are evidenced by current–voltage measurements. The breakdown voltage of these nanostructured varistors strongly depends on grain sizes. The results show that nanostructured varistors are obtained by SPS at sintering temperatures ranging from 550 to 600 °C.     

On the impact of mobility and soft vertical handoff on voice admission control in loosely coupled 3G/WLAN networks

Loose coupling between 3G and WLAN ensures flexibility and openness. However, providing an ubiquitousmobile voice service in a loosely coupled 3G/WLAN network requires both packet-level and call-level quality of service (QoS) guarantees using soft vertical handoff (SVHO) and call admission control (CAC). In this paper, we evaluate the impact of both SVHO and WLAN mobility on call blocking and dropping probabilities rederived for the integrated network. For this purpose, we propose a new multi-region mobility model that accurately estimate these probabilities under a resource-efficient dynamicthreshold SVHO compared to a standard static-threshold SVHO. Results show us that the resource-efficient SVHO blocks and drops much less voice calls than the static one when very low mean and high variability of multi-mode mobile station velocities are noticed. Therefore, resource-efficient SVHO implementations are highly recommended in these mobility environments.     

Asymptotic distribution of circularity coefficients estimate of complex random variables

In this correspondence we mainly consider the asymptotic distribution of the estimator of circularity coefficients of scalar and multidimensional complex random variables. A particular attention is paid to rectilinear RV. After deriving new properties of the circularity coefficients, the maximum likelihood estimate of the circularity coefficients in the Gaussian case and asymptotic distribution of this estimate for arbitrary distributions are given. Finally, an illustrative example is presented in order to strengthen the obtained theoretical results.