Dissociation of autonomic and behavioral components of conditioned fear during development in the rat.

Examined classical conditioning of heart rate (HR) in unrestrained preweanling and weanling Sprague-Dawley rats (aged 16, 19, 21, 25, and 28 days old), with tone and light as the conditioned stimulus/stimuli (CS) and electric shock as the unconditioned stimulus/stimuli (UCS). The conditioned cardiac response was a sustained deceleration in HR that did not emerge until Day 21 for the tone CS and until Day 28 for the light CS. In contrast, when suppression of a behavioral response (running in a straight alley for dry suckling as reward) was used as the index of conditioning, the suppressive effects of the CS were evident around Day 16 for the tone and around Day 19 for the light. Findings indicate that during ontogenesis (a) the behavioral and autonomic responses to the same CS do not develop at the same pace; (b) the emergence of conditioned responses (CRs) to tone and light stimuli parallel the sequential order in which the relevant sensory modalities achieve maturity (first audition, next vision); and (c) there is no clear-cut interdependence between development of the HR orienting response and conditionability of HR because unconditioned cardiac deceleration to both auditory and visual stimuli first appears about Day 16 in the developing rat, well before conditioned HR responses can be established to either stimulus. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some Future Perspectives for Unit Dose Inhalation Aerosols

Unit dose inhalation aerosols fail to achieve optimal lung deposition even though this can be achieved by dispersing 1-5 µm aerodynamic diameter particles in air. Dry powder generators require rapid inhalation for actuation and fail to deaggregate and release much of their powder charge because of high particulate adhesion forces. Conversely, pressurized metered dose inhalers (MDIs) fail because emergent propellant droplets are too large and travel too fast. The present unreliable dosimetry associated with the MDI stems from a desire to administer the whole of the metered dose. Rational design should concede on this point and concentrate on reducing primary droplet size and preventing emission of non-respirable large droplets. The loss of a constant proportion of each metered dose in the device and not the patient would be a major achievement. Improved inhalation dosimetry will facilitate future formulation developments designed to sustain local activity in the lung. This may be achieved by reducing particle dissolution rates in the airways.     

QUAD: a computer package for the analysis of QUantal assay data

The computer package QUAD has been developed at the University of Kent, U.K. It is menu-driven and written in Advanced BASIC. It runs on IBM PC compatible machines equiped with a suitable graphics facility such as CGA or simulated CGA. QUAD is available on a floppy disk, for a small handling charge.

QUAD has four main functions: it performs a logit analysis of quantal assay data; it provides a flexible way of analysing the data, allowing dose transformations and providing alternative confidence intervals for ED_p values; it produces a range diagnostics for assessing the fit of models to data; it provides and fits two families of extended models, each containing the logit as a special case.

The package makes use of the latest statistical research, and fitted models are displayed by means of the good graphics facilities available on microcomputers.

This document describes the facilities available in detail, and provides and discusses illustrations of the package at work. QUAD has been designed as a pilot package. Further additions and developments are planned and described later.     

End effects in scarf joints

Scarf joints with small scarf angles are especially sensitive to stiffness mismatch between adherends and to adherend tip bluntness. Pre-assembly breakage of an adherend tip where it is only a few microns thick can cause significant reduction in joint strength. Mathematically, the reason for such sensitivity is that the solutions to the governing differential equation develop boundary layer character when the scarf angles are small. The boundary layers are regions with large adhesive stresses. Experimental strength data for laminated composite adherends agree with the results of this analysis.     

Testing sequential association: Estimating exact p values using sampled permutations.

Assigning p values to all transitions in a matrix based on their z scores is problematic on 2 counts: The z scores may not be normally distributed, and transitions are interconnected. Permutation tests, which require far fewer assumptions, are an attractive alternative to the standard asymptotic methods for assigning significance. Moreover, when asymptotic z scores are only somewhat above their critical value and sequences are short, often the exact probabilities of permutation tests are not less than .05. Log-linear and permutation methods may be used to winnow the set of transitions initially identified as significant even further. A computer program that performs these tests is available from the authors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limits to power transmission in optical fibres

Measurements of the transmission characteristics of a multimode fibre have been performed to determine the power throughput limitations set by Raman scattering. The results show that, in the presence of severe pump depletion, the total transmitted power is effectively determined only by the fibre loss.     

Towards a systems approach for river basin management—Lessons from Australia's largest river

Globally, large river systems have been extensively modified and are increasingly managed for a range of purposes including ecosystem services and ecological values. Key to managing rivers effectively are developing approaches that deal with uncertainty, are adaptive in nature, and can incorporate multiple stakeholders with dynamic feedbacks. Australia's largest river system, the Murray–Darling Basin (MDB), has been extensively developed for shipping passage, irrigation, hydroelectric development, and water supply. Water development in the MDB over the last century resulted in overallocation of water resources and large‐scale environmental degradation throughout the Basin. Under the pressure of a significant drought, there was insufficient water to supply critical human, environmental, and agricultural needs. In response, a massive programme of water reform was enacted that resulted in considerable institutional, social, and economic change. The underlying policy was required to be enacted in an absence of certainty around the scientific basis, with an adaptive management focus to incorporate new knowledge. The resulting institutional arrangements were challenged by a need to generate new governance arrangements within the constraints of existing state and national structures. The ongoing reform and management of the MDB continues to challenge all parties to achieve optimization for multiple outcomes, and to communicate that effectively. As large‐scale water reform gains pace globally, the MDB provides a window of insight into the types of systems that may emerge and the challenges in working within them. Most particularly, it illustrates the need for much more sophisticated systems thinking that runs counter to the much more linear approaches often adopted in government.     

A multiscale correlation of wavelet coefficients approach to spike detection

Extracellular chronic recordings have been used as important evidence in neuroscientific studies to unveil the fundamental neural network mechanisms in the brain. Spike detection is the first step in the analysis of recorded neural waveforms to decipher useful information and provide useful signals for brain-machine interface applications. The process of spike detection is to extract action potentials from the recordings, which are often compounded with noise from different sources. This study proposes a new detection algorithm that leverages a technique from wavelet-based image edge detection. It utilizes the correlation between wavelet coefficients at different sampling scales to create a robust spike detector. The algorithm has one tuning parameter, which potentially reduces the subjectivity of detection results. Both artificial benchmark data sets and real neural recordings are used to evaluate the detection performance of the proposed algorithm. Compared with other detection algorithms, the proposed method has a comparable or better detection performance. In this letter, we also demonstrate its potential for real-time implementation.