A Tutorial on Fisher Information

In many statistical applications that concern mathematical psychologists, the concept of Fisher information plays an important role. In this tutorial we clarify the concept of Fisher information as it manifests itself across three different statistical paradigms. First, in the frequentist paradigm, Fisher information is used to construct hypothesis tests and confidence intervals using maximum likelihood estimators; second, in the Bayesian paradigm, Fisher information is used to define a default prior; lastly, in the minimum description length paradigm, Fisher information is used to measure model complexity

Bacterial dichloropropene degradation in soil:Screening of soils and involvement of plasmids carrying the dhlA gene

The nematocide cis-1,3-dichloropropene is widely used in intensive agricultural practice against root knot nematodes. As a result of the regular application of dichloropropene to six out of eight different soils, the compound was rapidly degraded to CO2, H2O and chloride ions in subsequent applications (adapted soils). Such degradation occurred at a lower rate in the same soil types without a history of dichloropropene use (unadapted soils). In two soils, the effect of repeated dichloropropene treatment was not found, since dichloropropene was already rapidly decomposed in the untreated controls. Since the dehalogenating enzyme haloalkane dehalogenase, encoded by the dhlA gene, is possibly involved in the degradation of dichloropropene, a specific PCR detection system combined with a dhlA probe was developed to detect dhlA in soil DNA extracts. Five of the eight adapted soils as well as three unadapted ones showed a response to this system, indicating the presence of DNA with sequence similarity to dhlA. Fifteen bacterial strains with dichloropropene-degradative capacity were isolated from enrichment cultures grown in the presence of this compound and inoculated with adapted soil (five soil types). Six selected isolates were identified as, respectively, Alcaligenes paradoxus, Pseudomonas cichorii I, Pseudomonas corrugata (2 x), Pseudomonas putida and Pseudomonas sp. Each of the six strains harboured a plasmid of 50-60 kb in size and all but one carried resistance to HgCl2. Filter matings were performed to investigate the possible cotransfer of biodegradative genes and Hg resistance to suitably-marked P. fluorescens R2f recipient strains. Three plasmid donor strains, P. cichorii I, P. corrugata and Pseudomonas sp., transferred the Hg resistance and the plasmid to the recipient used, suggesting that the Hg resistance marker was located on the plasmid. In addition, transconjugants produced with P. cichorii I and P. corrugata donor strains had also acquired 1,3-dichloropropene-degrading capability. PCR amplification with dhlA specific primers, of the plasmids obtained both from the original P. cichorii I and P. corrugata strains and from the respective transconjugant P. fluorescens R2f strains generated 400-500 bp amplification products. After cloning of the product of the P. cichorii I plasmid and sequencing of 180 bases, extensive homology with the dhlA gene was detected. These results suggest that a plasmid-located dhlA-like gene may be involved in dichloropropene degradation in soil by soil bacteria, but the extent to which the gene is involved in the process in situ is not clear.</p

Climate Change and Organic Farming in Developing Countries

What is the role of organic farming in mitigating the consequences of climate changes? This session provides background information and intends to initiate a debate among policy makers and stakeholders

Is There a Free Lunch in Inference?

The field of psychology, including cognitive science, is vexed by a crisis of confidence. Although the causes and solutions are varied, we focus here on a common logical problem in inference. The default mode of inference is significance testing, which has a free lunch property where researchers need not make detailed assumptions about the alternative to test the null hypothesis. We present the argument that there is no free lunch; that is, valid testing requires that researchers test the null against a well-specified alternative. We show how this requirement follows from the basic tenets of conventional and Bayesian probability. Moreover, we show in both the conventional and Bayesian framework that not specifying the alternative may lead to rejections of the null hypothesis with scant evidence. We review both frequentist and Bayesian approaches to specifying alternatives, and we show how such specifications improve inference. The field of cognitive science will benefit because consideration of reasonable alternatives will undoubtedly sharpen the intellectual underpinnings of research

Pediatric Brain Tumors:Narrating Suffering and End-of-Life Decisionmaking

When talking about decisionmaking for children with a life-threatening condition, the death of children with brain tumors deserves special attention. The last days of the lives of these children can be particularly harsh for bystanders, and raise questions about the suffering of these children themselves. In the Netherlands, these children are part of the group for whom a wide range of end-of-life decisions are discussed, and questions raised. What does the end-of-life for these children look like, and what motivates physicians and parents to make decisions that may affect the life and death of these children? This article highlights the story of the parents of the sisters Roos and Noor. When both their daughters were diagnosed with a hereditary brain tumor, they had to make similar decisions twice. Their story sheds light on the suffering of children in the terminal phase, and how this suffering may motivate parents and physicians to make decisions that influence the end of life of these children's lives.We argue that complete knowledge about suffering in the terminal phase of children with brain tumors is impossible. However, by collecting experiences like those of Roos and Noor, we can move toward an experienced-based understanding and better guide parents and physicians through these hardest of decisions

Timing of Pre-Operative Beta-Blocker Treatment in Vascular Surgery Patients Influence on Post-Operative Outcome

ObjectivesThis study evaluated timing of β-blocker initiation before surgery and its relationship with: 1) pre-operative heart rate and high-sensitivity C-reactive-protein (hs-CRP) levels; and 2) post-operative outcome.BackgroundPerioperative guidelines recommend β-blocker initiation days to weeks before surgery, on the basis of expert opinions.MethodsIn 940 vascular surgery patients, pre-operative heart rate and hs-CRP levels were recorded, next to timing of β-blocker initiation before surgery (0 to 1, >1 to 4, >4 weeks). Pre- and post-operative troponin-T measurements and electrocardiograms were performed routinely. End points were 30-day cardiac events (composite of myocardial infarction and cardiac mortality) and long-term mortality. Multivariate regression analyses, adjusted for cardiac risk factors, evaluated the relation between duration of β-blocker treatment and outcome.ResultsThe β-blockers were initiated 0 to 1, >1 to 4, and >4 weeks before surgery in 158 (17%), 393 (42%), and 389 (41%) patients, respectively. Median heart rate at baseline was 74 (±17) beats/min, 70 (±16) beats/min, and 66 (±15) beats/min (p < 0.001; comparing treatment initiation >1 with <1 week pre-operatively), and hs-CRP was 4.9 (±7.5) mg/l, 4.1 (±.6.0) mg/l, and 4.5 (±6.3) mg/l (p = 0.782), respectively. Treatment initiated >1 to 4 or >4 weeks before surgery was associated with a lower incidence of 30-day cardiac events (odds ratio: 0.46, 95% confidence interval [CI]: 0.27 to 0.76, odds ratio: 0.48, 95% CI: 0.29 to 0.79) and long-term mortality (hazard ratio: 0.52, 95% CI: 0.21 to 0.67, hazard ratio: 0.50, 95% CI: 0.25 to 0.71) compared with treatment initiated <1 week pre-operatively.ConclusionsOur results indicate that β-blocker treatment initiated >1 week before surgery is associated with lower pre-operative heart rate and improved outcome, compared with treatment initiated <1 week pre-operatively. No reduction of median hs-CRP levels was observed in patients receiving β-blocker treatment >1 week compared with patients in whom treatment was initiated between 0 and 1 week before surgery

Histoplasma-associated inflammatory pseudotumour of the kidney mimicking renal carcinoma

A 56-year-old female, originally from Suriname, with an otherwise unremarkable previous medical history was found to have a renal mass highly suspicious for renal cancer for which a nephrectomy was performed. Within the kidney, a tumourous mass was found which, on histological examination, showed an inflammatory pseudotumour caused by Histoplasma capsulatum. Further investigations revealed an idiopathic CD4+ lymphopenia. Mass lesions mimicking a malignant tumour caused by infection with Histoplasma have rarely been described. To the best of our knowledge, this is the first report of a Histoplasma-associated inflammatory pseudotumour mimicking cancer occurring in the kidney