The relative success of recognition-based inference in multichoice decisions

The utility of an "ecologically rational" recognition-based decision rule in multichoice decision problems is analyzed, varying the type of judgment required (greater or lesser). The maximum size and range of a counterintuitive advantage associated with recognition-based judgment (the "less-is-more effect") is identified for a range of cue validity values. Greater ranges of the less-is-more effect occur when participants are asked which is the greatest of to choices (m > 2) than which is the least. Less-is-more effects also have greater range for larger values of in. This implies that the classic two-altemative forced choice task, as studied by Goldstein and Gigerenzer (2002), may not be the most appropriate test case for less-is-more effects.

An intronic growth hormone receptor mutation causing activation of a pseudoexon is associated with a broad spectrum of growth hormone insensitivity phenotypes

Context: Inherited GH insensitivity (GHI) is usually caused by mutations in the GH receptor (GHR). Patients present with short stature associated with high GH and low IGF-I levels and may have midfacial hypoplasia ( typical Laron syndrome facial features). We previously described four mildly affected GHI patients with an intronic mutation in the GHR gene (A.(1) -> G.(1) substitution in intron 6), resulting in the activation of a pseudoexon (6 Psi) and inclusion of 36 amino acids. Objective: The study aimed to analyze the clinical and genetic characteristics of additional GHI patients with the pseudoexon (6 Psi) mutation. Design/Patients: Auxological, biochemical, genetic, and haplotype data from seven patients with severe short stature and biochemical evidence of GHI were assessed. Main Outcome Measures: We assessed genotype-phenotype relationship. Results: One patient belongs to the same extended family, previously reported. She has normal facial features, and her IGF-I levels are in the low-normal range for age. The six unrelated patients, four of whom have typical Laron syndrome facial features, have heights ranging from -3.3 to -6.0 SD and IGF-I levels that vary from normal to undetectable. We hypothesize that the marked difference in biochemical and clinical phenotypes might be caused by variations in the splicing efficiency of the pseudoexon. Conclusions: Activation of the pseudoexon in the GHR gene can lead to a variety of GHI phenotypes. Therefore, screening for the presence of this mutation should be performed in all GHI patients without mutations in the coding exons.

Expressing medicine side effects: assessing the effectiveness of absolute risk, relative risk, and number needed to harm, and the provision of baseline risk information

Objective: To assess the effectiveness of absolute risk, relative risk, and number needed to harm formats for medicine side effects, with and without the provision of baseline risk information. Methods: A two factor, risk increase format (relative, absolute and NNH) x baseline (present/absent) between participants design was used. A sample of 268 women was given a scenario about increase in side effect risk with third generation oral contraceptives, and were required to answer written questions to assess their understanding, satisfaction, and likelihood of continuing to take the drug. Results: Provision of baseline information significantly improved risk estimates and increased satisfaction, although the estimates were still considerably higher than the actual risk. No differences between presentation formats were observed when baseline information was presented. Without baseline information, absolute risk led to the most accurate performance. Conclusion: The findings support the importance of informing people about baseline level of risk when describing risk increases. In contrast, they offer no support for using number needed to harm. Practice implications: Health professionals should provide baseline risk information when presenting information about risk increases or decreases. More research is needed before numbers needed to harm (or treat) should be given to members of the general populations. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

Cooperative transport of extended payloads

In this paper we present experimental results for the dual robot transport of an extended payload. Two robotic rovers that were designed specifically for the extended payload transport task are described. Each rover incorporates a 4-DOF robot arm incorporating three active joints (one of which is a gripper), a passive wrist, and a mobile base which employs a rocker-bogie design. A set of behaviours has been developed to support the performance of the task, integrating simple sensing with controls. We describe the behaviours and their integration within the overall task structure. The experimental results presented focus on the manipulation elements of the task, but incorporate a complete cycle of pick-up, traversal, and putdown.

Suboptimal system recovery from communication loss in a multi-robot localization scenario using EKF algorithms

This paper describes a multi-robot localization scenario where, for a period of time, the robot team loses communication with one of the robots due to system error. In this novel approach, extended Kalman filter (EKF) algorithms utilize relative measurements to localize the robots in space. These measurements are used to reliably compensate "dead-com" periods were no information can be exchanged between the members of the robot group.

A relative path attenuation approximation algorithm for DVB-T systems

In the United Kingdom and in fact throughout Europe, the chosen standard for digital terrestrial television is the European Telecommunications Standards Institute (ETSI) ETN 300 744 also known as Digital Video Broadcasting - Terrestrial (DVB-T). The modulation method under this standard was chosen to be Orthogonal Frequency Division Multiplex (0FD4 because of the apparent inherent capability for withstanding the effects of multipath. Within the DVB-T standard, the addition of pilot tones was included that can be used for many applications such as channel impulse response estimation or local oscillator phase and frequency offset estimation. This paper demonstrates a technique for an estimation of the relative path attenuation of a single multipath signal that can be used as a simple firmware update for a commercial set-top box. This technique can be used to help eliminate the effects of multipath(1).

Propagation of errors from a null balance terahertz reflectometer to a sample's relative water content

The THz water content index of a sample is defined and advantages in using such metric in estimating a sample's relative water content are discussed. The errors from reflectance measurements performed at two different THz frequencies using a quasi-optical null-balance reflectometer are propagated to the errors in estimating the sample water content index.

A neurofuzzy network knowledge extraction and extended gram-Schmidt algorithm for model subspace decomposition

This paper introduces a new neurofuzzy model construction and parameter estimation algorithm from observed finite data sets, based on a Takagi and Sugeno (T-S) inference mechanism and a new extended Gram-Schmidt orthogonal decomposition algorithm, for the modeling of a priori unknown dynamical systems in the form of a set of fuzzy rules. The first contribution of the paper is the introduction of a one to one mapping between a fuzzy rule-base and a model matrix feature subspace using the T-S inference mechanism. This link enables the numerical properties associated with a rule-based matrix subspace, the relationships amongst these matrix subspaces, and the correlation between the output vector and a rule-base matrix subspace, to be investigated and extracted as rule-based knowledge to enhance model transparency. The matrix subspace spanned by a fuzzy rule is initially derived as the input regression matrix multiplied by a weighting matrix that consists of the corresponding fuzzy membership functions over the training data set. Model transparency is explored by the derivation of an equivalence between an A-optimality experimental design criterion of the weighting matrix and the average model output sensitivity to the fuzzy rule, so that rule-bases can be effectively measured by their identifiability via the A-optimality experimental design criterion. The A-optimality experimental design criterion of the weighting matrices of fuzzy rules is used to construct an initial model rule-base. An extended Gram-Schmidt algorithm is then developed to estimate the parameter vector for each rule. This new algorithm decomposes the model rule-bases via an orthogonal subspace decomposition approach, so as to enhance model transparency with the capability of interpreting the derived rule-base energy level. This new approach is computationally simpler than the conventional Gram-Schmidt algorithm for resolving high dimensional regression problems, whereby it is computationally desirable to decompose complex models into a few submodels rather than a single model with large number of input variables and the associated curse of dimensionality problem. Numerical examples are included to demonstrate the effectiveness of the proposed new algorithm.

Pupal parasitoid attack influences the relative fitness of Drosophila that have encapsulated larval parasitoids

1. The evolution of host resistance to parasitoid attack will be constrained by two factors: the costs of the ability to defend against attack, and the costs of surviving actual attack. These factors have been investigated using Drosophila melanogaster and its parasitoids as a model system. The costs of defensive ability are expressed as a trade-off with larval competitive ability, whereas the costs of actual defence are exhibited in terms of reduced adult fecundity and size. 2. The costs of actual defence may be ameliorated by the host-choice decisions made by Pachycrepoideus vindemiae, a pupal parasitoid. If larvae that have successfully encapsulated a parasitoid develop into poorer quality hosts, then these may be rejected by ovipositing pupal parasitoids. 3. Pupae developing from larvae that have encapsulated the parasitoid Asobara tabida are smaller and have relatively thinner puparia. Thinner puparia are likely to be associated with a reduction in mechanical strength and possibly with a decrease in desiccation tolerance. 4. Pachycrepoideus vindemiae that develop in capsule-bearing pupae are smaller than those that emerge from previously unattacked hosts. This supports the prediction that ovipositing female P. vindemiae should avoid attacking capsule-bearing hosts. However, in choice experiments with 1-day-old pupae, P. vindemiae females oviposited preferentially in hosts containing a capsule, whereas there was no preference found with 4-day-old hosts. This appears to be a maladaptive host choice decision, as the female pupal parasitoids are preferentially attacking hosts that will result in a reduction of their own fitness. 5. The increased likelihood of attack by a pupal parasitoid is another cost of actual defence against larval parasitoid attack.

The relative fitness of Drosophila melanogaster (Diptera, Drosophilidae) that have successfully defended themselves against the parasitoid Asobara tabida (Hymenoptera, Braconidae)

Drosophila melanogaster larvae defend themselves against parasitoid attack via the process of encapsulation. However, flies that successfully defend them selves have reduced fitness as adults. Adults which carry an encapsulated parasitoid egg are smaller and females produce significantly fewer eggs than controls. Capsule-bearing males allowed repeated copulations with females do not show a reduction in their number of offspring, but those allowed to copulate only once did. No differences were found in time to first oviposition in females, or in time to first copulation in males. We interpret the results as arising from a trade-off between investing resources in factors promoting fecundity and mating success, and in defence against parasitism. The outcome of this investment decision influences the strength of selection for defence against parasitism.

Gene-nutrient interactions with dietary fat modulate the association between genetic variation of the ACSL1 gene and metabolic syndrome

Long-chain acyl CoA synthetase 1 (ACSL1) plays an important role in fatty acid metabolism and triacylglycerol (TAG) synthesis. Disturbance of these pathways may result in dyslipidemia and insulin resistance, hallmarks of the metabolic syndrome (MetS). Dietary fat is a key environmental factor that may interact with genetic determinants of lipid metabolism to affect MetS risk. We investigated the relationship between ACSL1 polymorphisms (rs4862417, rs6552828, rs13120078, rs9997745, and rs12503643) and MetS risk and determined potential interactions with dietary fat in the LIPGENE-SU.VI.MAX study of MetS cases and matched controls (n = 1,754). GG homozygotes for rs9997745 had increased MetS risk {odds ratio (OR) 1.90 [confidence interval (CI) 1.15, 3.13]; P = 0.01}, displayed elevated fasting glucose (P = 0.001) and insulin concentrations (P = 0.002) and increased insulin resistance (P = 0.03) relative to the A allele carriers. MetS risk was modulated by dietary fat, whereby the risk conferred by GG homozygosity was abolished among individuals consuming either a low-fat (<35% energy) or a high-PUFA diet (>5.5% energy). In conclusion, ACSL1 rs9997745 influences MetS risk, most likely via disturbances in fatty acid metabolism, which was modulated by dietary fat consumption, particularly PUFA intake, suggesting novel gene-nutrient interactions.

Meson properties in an extended nonlocal NJL model

We consider a non-local version of the NJL model, based on a separable quark-quark interaction. The interaction is extended to include terms that bind vector and axial-vector mesons. The non-locality means that no further regulator is required. Moreover the model is able to confine the quarks by generating a quark propagator without poles at real energies. Working in the ladder approximation, we calculate amplitudes in Euclidean space and discuss features of their continuation to Minkowski energies. Conserved currents are constructed and we demonstrate their consistency with various Ward identities. Various meson masses are calculated, along with their strong and electromagnetic decay amplitudes. We also calculate the electromagnetic form factor of the pion, as well as form factors associated with the processes γγ* → π0 and ω → π0γ*. The results are found to lead to a satisfactory phenomenology and lend some dynamical support to the idea of vector-meson dominance.