Effects of continuous versus periodic milk availability on behavior and performance of dairy calves

Dairy calves fed milk ad libitum engage in feeding activity throughout the day and night. However, providing calves with continuous access to milk can present practical problems with milk quality, particularly during warm weather. One way to maintain milk quality in ad libitum feeding regimens is to limit the time that milk is available, but no research to date has addressed how this might affect calves. The objectives of this study were to quantify the effects of continuous access to milk (24 h/d) vs. access during only part of the day on milk feeding behavior and performance. Twenty-eight female Holstein calves were randomly assigned to treatments at 5 ± 3 d of age and monitored for 28 d. All calves had milk delivered through a teat. Treatments were 1) access to milk for 24 h/d; 2) access to milk for 2 feedings per day (each of 2 h), with water available through the teat the remainder of the day (4-h wet treatment); and, 3) access to milk for 2 feedings per day (each of 2 h), but with no water available through the teat (4-h dry treatment). Calves given 24-h access to milk consumed 11.2 ± 0.5 kg/d on average. Milk intake tended to be lower for the 4-h wet and 4-h dry treatments, averaging 10.0 ± 0.3 kg/d, with no difference between these 2 treatments in this or any other variable. Average daily gain over the course of the experiment did not vary with treatment and averaged 1.1 ± 0.04 kg/d. Calves in the 24-h treatment spent more time on the teat than those calves on the 4-h treatments, but during the 4 h/d when milk was available to all calves, calves in the 4-h treatments spent more time on the teat. These results show that individually housed calves fed milk ad libitum for only 4 h/d compensate by changing their milk feeding behavior and are able to achieve similar weight gains to animals fed milk continuously.     

Semiautomatic Analysis of Phase Contrast Magnetic Resonance Imaging of Cerebrospinal Fluid Flow through the Aqueduct of Sylvius

Objective: Quantification of the cerebrospinal fluid (CSF) flow through the aqueduct of Sylvius by means of magnetic resonance imaging (MRI) is subject to interobserver variability due to the region of interest (ROI) selection. Our objective is to develop a semiautomatic measurement method to achieve reproducible quantitative analysis of CSF flow rate and stroke volume. Material and methods: MR examinations were performed using a 1.5 T scanner with a phase contrast sequence (velocity encoding [V _enc] of 20 cm/s, FOV = 160, 3 mm slice thickness, image matrix size = 256×256, TR = 53 ms, TE = 11 ms, NSA = 2, flip angle = 15° and 23 frames per cardiac cycle with peripheral retrospective pulse gating). Our method was developed using MATLAB R7. Errors introduced by background offset and possible aliased pixels were automatically detected and corrected if necessary in order to calculate the flow parameters that characterize CSF dynamics. The semiautomatic seed method reproducibility was evaluated and compared with the radius method by two observers analysing 21 healthy subjects. Results: The measurements using the semiautomatic seed method reduced the interobservers variability (intra-class correlation [ICC] = 1.0 for stroke volume and for volumetric flow rate) versus the radius method (ICC = 0.46 for stroke volume and 0.65 for flow rate). Normal stroke volume (39.19 ± 20.13 μl/cycle), flow rate (3.81 ± 2.81 ml/min), maximal mean systolic velocity (5.27 ± 1.3 cm/s) and maximal mean diastolic velocity (4.20 ± 1.4 cm/s) were calculated with the half moon and aliasing corrected seed method. Conclusions: Semiautomatic measurements (seed method with half moon background and aliasing correction) allow a generalization of the calculus of flow parameters with great consistency and independency of the operator.     

Editorial

Telecommunication Systems -     

Parametric study of chemical looping combustion for tri‐generation of hydrogen,heat, and electrical power with CO2 capture

In this article, a novel cycle configuration has been studied, termed the extended chemical looping combustion integrated in a steam‐injected gas turbine cycle. The products of this system are hydrogen, heat, and electrical power. Furthermore, the system inherently separates the CO₂ and hydrogen that is produced during the combustion. The core process is an extended chemical looping combustion (exCLC) process which is based on classical chemical looping combustion (CLC). In classical CLC, a solid oxygen carrier circulates between two fluidized bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO₂ separation occurs. In exCLC the oxygen carrier circulates along with a carbon carrier between three fluidized bed reactors, one to oxidize the oxygen carrier, one to produces and separate the hydrogen, and one to regenerate the carbon carrier. The impacts of process parameters, such as flowrates and temperatures have been studied on the efficiencies of producing electrical power, hydrogen, and district heating and on the degree of capturing CO₂. The result shows that this process has the potential to achieve a thermal efficiency of 54% while 96% of the CO₂ is captured and compressed to 110 bar. Copyright © 2005 John Wiley & Sons, Ltd.     

Approximate arithmetic coding for bus transition reduction in low power designs

We present a method for reducing the power consumption of compressed-code systems by selectively inverting bits that are transmitted on the bus. By incorporating bus inversion into code compression/decompression, we reduce power consumption with no cost in hardware or power relative to code compression without inversion. Inverting has to be done carefully to ensure that the codes can still be decoded. As an additional challenge, compression will generally increase bit-toggling as it removes redundancies from the code transmitted. Therefore, we need to find the right balance between compression ratio and bit-toggling reduction. This paper presents a suitable algorithm that will combine approximate compression techniques with bit-toggling reduction and will explore the various tradeoffs. We take advantage of the approximations introduced to modify codes and reduce bit-toggling, while maintaining compression performance and decoding speed. An interesting result that is derived from our work is that high compression ratios do not necessarily result in the lowest power consumption. By using our method, bus-related power consumption has been reduced by as much as 35% compared to a system with no compression, and as much as 14% compared to a compressed-code system. Bit-toggling reduction does not impose any additional hardware costs other than the decompression engine. We also present a detailed analysis on how bus widths affect bit-toggling when transmitting compressed code, and we show experimental results on ARM, MIPS, and SPARC code. We finally compare our work with Bus Invert and show results that are superior except for the random data case where Bus Invert performs better.     

A Dedicated TLP Set-Up to Investigate the ESD Robustness of RF Elements and Circuits

This work describes the development of a combined RF-TLP test set-up. It alternates between pulsed high current characterization and scattering parameter measurements up to 10 GHz in order to investigate the influence of the stress pulses on the RF behaviour of the DUT. As an example, the high current behaviour of a broad band amplifier circuit is analyzed.     

Test circuits for fast and reliable assessment of CDM robustness of I/O stages

CDM hardening during the development of technology, devices, libraries and finally products differs significantly from the process well-established for HBM. This paper introduces a method on the basis of specialized CDM test structures including protection elements and sensitive monitor elements. These test structures mimic typical CDM-sensitive circuits found by physical failure analysis over the years. Manufactured in five different technologies, structures were assembled in both a regular package and a new package emulator. CDM stress tests, very-fast TLP tests, transient interferometric mapping, device simulation, and failure analysis lead to new insights in the complex interdependencies during CDM and underline the need of CDM-specific test structures.     

Sustainable management of leakage from wastewater pipelines.

Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.