The smooth fractionator

A modification of the general fractionator sampling technique called the smooth fractionator is presented. It may be used in almost every situation in which sampling is performed from distinct items that are uniquely defined, often they are physically separated items or clusters like pieces, blocks, slabs, sections, etc. To each item is associated a ‘guesstimate’ or an associated variable with a more‐or‐less close – and possibly biased ? relationship to the content of the item. The smooth fractionator is systematic sampling among the items arranged according to the guesstimates in a unique, symmetric sequence with one peak and minimal jumps. The smooth fractionator is both very simple to implement and so efficient that it should probably always be used unless the natural sequence of the sampling items is equally smooth. So far, there is no theory for the prediction of the efficiency of smooth fractionator designs in general, and their properties are therefore illustrated with a range of real and simulated examples. At the cost of a slightly more elaborate sampling scheme, it is, however, always possible to obtain an unbiased estimate of the real precision and of some of the variance components. The only real practical problem for always obtaining a high precision with the smooth fractionator is specimen inhomogeneity, but that is detectable at almost no extra cost. With careful designs and for sample sizes of about 10, the sampling variation for the primary, smooth fractionator sampling step may in practice often be small enough to be ignored.     

Spontaneous output of acetylcholine from rat diaphragm preparations declines after treatment with botulinum toxin

A gas chromatographic spectrometric assay was used to measure tissue and released acetylcholine and choline in diaphragm preparations of rats previously injected with botulinum toxin type A. Botulinum intoxication was found not to alter the acetylcholine content of rat diaphragms in vivo or in fully paralyzed muscles in vitro. This result provides direct support for the hypothesis that botulinum toxin blocks transmitter release without affecting acetylcholine synthesis. However, in diaphragm preparations in vitro, this toxin was found to inhibit not only the evoked release of acetylcholine but also the spontaneous "leakage" of acetylcholine that is measured at rest. Additional experiments were performed to characterize this action of the toxin. The magnitude of the decline in resting acetylcholine output appears to be too large to be accounted for solely by the known effect of botulinum toxin to reduce the frequency of miniature endplate potentials. The mechanism of this action of botulinum toxin remains an enigma.     

Process design methodology for energy‐efficient processes operating below and across ambient temperature

This article presents a targeting and design methodology that can be implemented for any process where pressure‐based exergy, also known as mechanical exergy, has an important contribution to the total exergy conversion and transfer. However, in this article it is applied to processes that operate at sub‐ambient conditions, or processes where the ambient conditions are crossed. Exergy efficiencies, new Exergetic Composite Curves, Cascades, and Extended Grid Diagrams are tools that had to be implemented, improved, or invented, to develop a methodology with considerable potential for energy‐efficient process design. The appropriate placement (correct integration) of compressors and expanders in heat exchanger networks is also analyzed to minimize the number of units. An example is used to demonstrate the methodology, where several simplifying assumptions are made to facilitate understanding and to explain the design method. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2324–2340, 2016     

Cardiopulmonary complications in acute subarachnoid hemorrhage

Pathologic electrocardiogram (ECG) may be present in more than 90% of patients with subarachnoid haemorrhage. The ECG findings are often transient and may mimic acute myocardial ischaemia or infarction. These ECG findings may cause diagnostic problems in patients with subarachnoid haemorrhage who are unconscious or who have atypical symptoms. Life-threatening arrhythmias are also seen and may be responsible for sudden deaths in patients with subarachnoid haemorrhage. Other signs of myocardial injury, such as ventricular wall motion dysfunction, elevated enzymes, and histological evidence of contraction band necrosis are described. The myocardial dysfunction known as neurogenic stunned myocardium is reversible if the patient survives the acute phase, but it may lead to haemodynamic instability and contribute to the origin of neurogenic pulmonary oedema. The myocardial injury in subarachnoid haemorrhage may be due to a massive sympathetic stimulation of the myocardium in response to rapidly increasing intracranial pressure. We illustrate myocardial injury and dysfunction in a case report where a patient had subarachnoid haemorrhage with ventricular fibrillation, pulmonary oedema, left ventricular dysfunction and ST-segment elevation, initially thought to be acute myocardial infarction.     

Global spatial sampling with isotropic virtual planes: estimators of length density and total length in thick, arbitrarily orientated sections

Existing design-based direct length estimators require random rotation around at least one axis of the tissue specimen prior to sectioning to ensure isotropy of test probes. In some tissue it is, however, difficult or even impossible to define the region of interest, unless the tissue is sectioned in a specific, nonrandom orientation. Spatial uniform sampling with isotropic virtual planes circumvents the use of physically isotropic or vertical sections. The structure that is contained in a thick physical section is investigated with software-randomized isotropic virtual planes in volume probes in systematically sampled microscope fields using computer-assisted stereological analysis. A fixed volume of 3D space in each uniformly sampled field is probed with systematic random, isotropic virtual planes by a line that moves across the computer screen showing live video images of the microscope field when the test volume is scanned with a focal plane. The intersections between the linear structure and the virtual probes are counted with columns of two dimensional disectors.
Global spatial sampling with sets of isotropic uniform random virtual planes provides a basis for length density estimates from a set of parallel physical sections of any orientation preferred by the investigator, i.e. the simplest sampling scheme in stereology. Additional virtues include optimal conditions for reducing the estimator variance, the possibility to estimate total length directly using a fractionator design and the potential to estimate efficiently the distribution of directions from a set of parallel physical sections with arbitrary orientation.
Other implementations of the basic idea, systematic uniform sampling using probes that have total 3D × 4π freedom inside the section, and therefore independent of the position and the orientation of the physical section, are briefly discussed.     

A multiagent framework for coordinated parallel problem solving

Today’s organizations, under increasing pressure on the effectiveness and the increasing need for dealing with complex tasks beyond a single individual’s capabilities, need technological support in managing complex tasks that involve highly distributed and heterogeneous information sources and several actors. This paper describes CoPSF, a multiagent system middle-ware that simplifies the development of coordinated problem solving applications while ensuring standard compliance through a set of system services and agents. CoPSF hosts and serves multiple concurrent teams of problem solving contributing both to the limitation of communication overheads and to the reduction of redundant work across teams and organizations. The framework employs (i) an interleaved task decomposition and allocation approach, (ii) a mechanism for coordination of agents’ work, and (iii) a mechanism that enables synergy between parallel teams.     

Causes and consequences of natal dispersal in root voles, Microtus oeconomus

To test the causes and consequences of variation in natal dispersal in root voles we released 53 matrilines (mothers with newly weaned litters) separately in field enclosures, during nine consecutive periods. The matrilines could disperse and distribute themselves among three pre-emptied habitat patches. Two dispersal measures were recorded: short-distance dispersal defined as individuals immigrating to a neighbouring patch, and long-distance dispersal defined as unsettled individuals captured along the fence of the enclosures. We analysed the role of social factors (i.e. maternal and litter characteristics), habitat quality (i.e. seasonal effect) and experimentally manipulated shape of the natal patch in dispersal. The consequences of dispersal were analysed with respect to the spatial distribution of kin, and to pregnancy in females and sexual maturation in males. Dispersal was unrelated to patch shape. In agreement with the inbreeding avoidance hypothesis, long-distance dispersal was male biased and philopatric males were most frequently reproductively inactive. Whilst young males avoided their mother, they seemed to disperse, settle and mature sexually independently of their sisters. In agreement with the resource competition hypothesis, young females avoided their mother and were most frequently reproductively inactive when residing in their mother's patch. We conclude that inbreeding avoidance was underlying the male dispersal pattern. For females, long-distance dispersal was most in agreement with the inbreeding avoidance hypothesis while short-distance dispersal could be explained by the resource competition hypothesis. (c) 1998 The Association for the Study of Animal Behaviour.     

Ultrashort pulsed electric fields induce membrane phospholipid translocation and caspase activation: differential sensitivities of Jurkat T lymphoblasts and rat glioma C6 cells

Megavolt-per-meter electric pulses with durations shorter than charging time constants associated with external cell membrane dielectric properties can generate significant voltages on the membranes of intracellular structures. Nanosecond-duration, high-field (2-4 MV/m) pulses are not immediately lethal to cells and do not produce the conductive openings in the cytoplasmic membrane associated with long-pulse, low-field electroporation, but can induce profound physiological changes, including apoptosis (programmed cell death). We demonstrate rapid, non-destructive, field-dependent translocation of the plasma membrane inner leaflet phospholipid phosphatidylserine in Jurkat T lymphocytes, and we show that cells which exhibit a similar geometry in suspension, rat glioma C6 cells, are highly resistant to these pulses and respond differently even to much higher doses.     

Research issues in developing compact pulsed power for high peak power applications on mobile platforms

Pulsed power is a technology that is suited to drive electrical loads requiring very large power pulses in short bursts (high-peak power). Certain applications require technology that can be deployed in small spaces under stressful environments, e.g., on a ship, vehicle, or aircraft. In 2001, the U.S. Department of Defense (DoD) launched a long-range (five-year) Multidisciplinary University Research Initiative (MURI) to study fundamental issues for compact pulsed power. This research program is endeavoring to: 1) introduce new materials for use in pulsed power systems; 2) examine alternative topologies for compact pulse generation; 3) study pulsed power switches, including pseudospark switches; and 4) investigate the basic physics related to the generation of pulsed power, such as the behavior of liquid dielectrics under intense electric field conditions. Furthermore, the integration of all of these building blocks is impacted by system architecture (how things are put together). This paper reviews the advances put forth to date by the researchers in this program and will assess the potential impact for future development of compact pulsed power systems.     

Pre-rigor filleting and brining of farmed cod: Influence on quality and storage stability

Pre-rigor filleting as well as brining with a mixture of phosphates and salt could influence several quality parameters of cod fillets. The aim of this work was to evaluate which of these processes that affected selected quality parameters of farmed cod the most. The analyses were performed at several points during storage, enabling that the effects of time of filleting, brining and storage could be evaluated simultaneously.Pre- and post-rigor non-brined fillets had similar and significant weight loss during storage. The weight increase of pre- and post-rigor fillets due to brining were 2% and almost 10%, respectively, and brining significantly reduced the weight loss during storage. Liquid loss and total viable count (TVC) were significantly influenced by rigor state at time of filleting, brining and storage time, while water content was influenced significantly by time of filleting and brining. Brining and storage time significantly influenced the whiteness, while time of filleting and storage time had significant influence upon the fillet index. The growth of Photobacterium phosphoreum was affected by storage time only, and the pH of the fillets was not influenced significantly by any of the parameters tested.