815 research outputs found
Measuring the intelligence of an idealized mechanical knowing agent
We define a notion of the intelligence level of an idealized mechanical knowing agent. This is motivated by efforts within artificial intelligence research to define real-number intelligence levels of compli- cated intelligent systems. Our agents are more idealized, which allows us to define a much simpler measure of intelligence level for them. In short, we define the intelligence level of a mechanical knowing agent to be the supremum of the computable ordinals that have codes the agent knows to be codes of computable ordinals. We prove that if one agent knows certain things about another agent, then the former necessarily has a higher intelligence level than the latter. This allows our intelligence no- tion to serve as a stepping stone to obtain results which, by themselves, are not stated in terms of our intelligence notion (results of potential in- terest even to readers totally skeptical that our notion correctly captures intelligence). As an application, we argue that these results comprise evidence against the possibility of intelligence explosion (that is, the no- tion that sufficiently intelligent machines will eventually be capable of designing even more intelligent machines, which can then design even more intelligent machines, and so on)
Do pilocarpine drops help dry mouth in palliative care patients: A protocol for an aggregated series of n-of-1 trials
Background: It is estimated that 39,000 Australians die from malignant disease yearly. Of these, 60% to 88% of advanced cancer patients suffer xerostomia, the subjective feeling of mouth dryness. Xerostomia has significant physical, social and psychological consequences which compromise function and quality of life. Pilocarpine is one treatment for xerostomia. Most studies have shown some variation in individual response to pilocarpine, in terms of dose used, and timing and extent of response.We will determine a population estimate of the efficacy of pilocarpine drops (6 mg) three times daily compared to placebo in relieving dry mouth in palliative care (PC) patients. A secondary aim is to assess individual patients' response to pilocarpine and provide reports detailing individual response to patients and their treating clinician. Methods/Design. Aggregated n-of-1 trials (3 cycle, double blind, placebo-controlled crossover trials using standardized measures of effect). Individual trials will identify which patients respond to the medication. To produce a population estimate of a treatment effect, the results of all cycles will be aggregated. Discussion. Managing dry mouth with treatment supported by the best possible evidence will improve functional status of patients, and improve quality of life for patients and carers. Using n-of-1 trials will accelerate the rate of accumulation of high-grade evidence to support clinical therapies used in PC. Trial registration. Australia and New Zealand Clinical Trial Registry Number: 12610000840088. © 2013 Nikles et al.; licensee BioMed Central Ltd
Garden varieties: how attractive are recommended garden plants to butterflies?
One way the public can engage in insect conservation is through wildlife gardening, including the growing of insect-friendly flowers as sources of nectar. However, plant varieties differ in the types of insects they attract. To determine which garden plants attracted which butterflies, we counted butterflies nectaring on 11 varieties of summer-flowering garden plants in a rural garden in East Sussex, UK. These plants were all from a list of 100 varieties considered attractive to British butterflies, and included the five varieties specifically listed by the UK charity Butterfly Conservation as best for summer nectar. A total of 2659 flower visits from 14 butterfly and one moth species were observed. We performed a principal components analysis which showed contrasting patterns between the species attracted to Origanum vulgare and Buddleia davidii. The “butterfly bush” Buddleia attracted many nymphalines, such as the peacock, Inachis io, but very few satyrines such as the gatekeeper, Pyronia tithonus, which mostly visited Origanum. Eupatorium cannibinum had the highest Simpson’s Diversity score of 0.75, while Buddleia and Origanum were lower, scoring 0.66 and 0.50 respectively. No one plant was good at attracting all observed butterfly species, as each attracted only a subset of the butterfly community. We conclude that to create a butterfly-friendly garden, a variety of plant species are required as nectar sources for butterflies. Furthermore, garden plant recommendations can probably benefit from being more precise as to the species of butterfly they attract
Multicentric validation of proteomic biomarkers in urine specific for diabetic nephropathy
Background: Urine proteome analysis is rapidly emerging as a tool for diagnosis and prognosis in disease states. For diagnosis of diabetic nephropathy (DN), urinary proteome analysis was successfully applied in a pilot study. The validity of the previously established proteomic biomarkers with respect to the diagnostic and prognostic potential was assessed on a separate set of patients recruited at three different European centers. In this case-control study of 148 Caucasian patients with diabetes mellitus type 2 and duration >= 5 years, cases of DN were defined as albuminuria >300 mg/d and diabetic retinopathy (n = 66). Controls were matched for gender and diabetes duration (n = 82).
Methodology/Principal Findings: Proteome analysis was performed blinded using high-resolution capillary electrophoresis coupled with mass spectrometry (CE-MS). Data were evaluated employing the previously developed model for DN. Upon unblinding, the model for DN showed 93.8% sensitivity and 91.4% specificity, with an AUC of 0.948 (95% CI 0.898-0.978). Of 65 previously identified peptides, 60 were significantly different between cases and controls of this study. In <10% of cases and controls classification by proteome analysis not entirely resulted in the expected clinical outcome. Analysis of patient's subsequent clinical course revealed later progression to DN in some of the false positive classified DN control patients.
Conclusions: These data provide the first independent confirmation that profiling of the urinary proteome by CE-MS can adequately identify subjects with DN, supporting the generalizability of this approach. The data further establish urinary collagen fragments as biomarkers for diabetes-induced renal damage that may serve as earlier and more specific biomarkers than the currently used urinary albumin
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A Novel Method for Rapid and Quantitative Mechanical Assessment of Soft Tissue for Diagnostic Purposes: A Computational Study
Biological tissues often experience drastic changes in their microstructure due to their pathophysiological conditions. Such microstructural changes could result in variations in mechanical properties, which can be used in diagnosing or monitoring a wide range of diseases, most notably cancer. This paves the avenue for non-invasive diagnosis by instrumented palpation although challenges remain in quantitatively assessing the amount of diseased tissue by means of mechanical characterization. This paper presents a framework for tissue diagnosis using a quantitative and efficient estimation of the fractions of cancerous and non-cancerous tissue without a priori knowledge of tissue microstructure. First, the sample is tested in a creep or stress relaxation experiment, and the behavior is characterized using a single term Prony series. A rule of mixtures, which relates tumor fraction to the apparent mechanical properties, is then obtained by minimizing the difference between strain energy of a heterogeneous system and an equivalent homogeneous one. Finally, the percentage of each tissue constituent is predicted by comparing the observed relaxation time with that calculated from the rule of mixtures. The proposed methodology is assessed using models reconstructed from histological samples and magnetic resonance imaging of prostate. Results show that estimation of cancerous tissue fraction can be obtained with a maximum error of 12% when samples of different sizes, geometries, and tumor fractions are presented. The proposed framework has the potential to be applied to a wide range of diseases such as rectal polyps, cirrhosis, or breast and prostate cancer whose current primary diagnosis remains qualitative.The support under grant nos. EP/I019472/1 and EP/I020101/1 from the Engineering and Physical Sciences Research Council (EPSRC) is greatly acknowledged. The authors also acknowledge Dr. M O'Donnell (Consultant Uropathologist, Western General Hospital) for the pathohistological analysis and Dr. Maurits Jansen and Ross Lennen from the University of Edinburgh for performing the MRI study
Quantum fields during black hole formation: how good an approximation is the Unruh state?
We study the quantum effects of a test Klein-Gordon field in a Vaidya space-time consisting of a collapsing null shell that forms a Schwazschild black hole, by explicitly obtaining, in a (1 + 1)-dimensional model, the Wightman function, the renormalised stress-energy tensor, and by analysing particle detector rates along stationary orbits in the exterior black hole region, and make a comparison with the folklore that the Unruh state is the state that emerges from black hole formation. In the causal future of the shell, we find a negative ingoing flux at the horizon that agrees precisely with the Unruh state calculation, and is the source of black hole radiation, while in the future null infinity we find that the radiation flux output in the Unruh state is an upper bound for the positive outgoing flux in the collapsing null shell spacetime. This indicates that back-reaction estimates based on Unruh state calculations over-estimate the energy output carried by so-called pre-Hawking radiation. The value of the output predicted by the Unruh state is however approached exponentially fast. Finally, we find that at late times, stationary observers in the exterior black hole region in the collapsing shell spacetime detect the local Hawking temperature, which is also well characterised by the Unruh state, coming from right-movers. Early-time discrepancies between the detector rates for the Unruh state and for the state in the collapsing shell spacetime are explored numerically
Acetabular fractures following rugby tackles: a case series
<p>Abstract</p> <p>Introduction</p> <p>Rugby is the third most popular team contact sport in the world and is increasing in popularity. In 1995, rugby in Europe turned professional, and with this has come an increased rate of injury.</p> <p>Case presentation</p> <p>In a six-month period from July to December, two open reduction and internal fixations of acetabular fractures were performed in young Caucasian men (16 and 24 years old) who sustained their injuries after rugby tackles. Both of these cases are described as well as the biomechanical factors contributing to the fracture and the recovery. Acetabular fractures of the hip during sport are rare occurrences.</p> <p>Conclusion</p> <p>Our recent experience of two cases over a six-month period creates concern that these high-energy injuries may become more frequent as rugby continues to adopt advanced training regimens. Protective equipment is unlikely to reduce the forces imparted across the hip joint; however, limiting 'the tackle' to only two players may well reduce the likelihood of this life-altering injury.</p
Mechanism of Protection Induced by Group A Streptococcus Vaccine Candidate J8-DT: Contribution of B and T-Cells Towards Protection
Vaccination with J8-DT, a leading GAS vaccine candidate, results in protective immunity in mice. Analysis of immunologic correlates of protection indicated a role of J8-specific antibodies that were induced post-immunization. In the present study, several independent experimental approaches were employed to investigate the protective immunological mechanisms involved in J8-DT-mediated immunity. These approaches included the passive transfer of mouse or rabbit immune serum/antibodies in addition to selective depletion of T-cell subsets prior to bacterial challenge. Passive transfer of J8-DT antiserum/antibodies from mice and rabbits conferred significant resistance against challenge to mice. To exclude the possibility of involvement of other host immune factors, the studies were repeated in SCID mice, which highlighted the need for an ongoing immune response for long-lived protection. Depletion of CD4+ and CD8+ T-cell subsets confirmed that an active de novo immune response, involving CD4+ T-helper cells, is required for continued synthesis of antibodies resulting in protection against GAS infection. Taken together these results indicate an involvement of CD4+ T-cells in J8-DT-mediated protection possibly via an ability to maintain antibody levels. These results have considerable relevance to the development of a broad spectrum passive immunotherapy for GAS disease
Current challenges in software solutions for mass spectrometry-based quantitative proteomics
This work was in part supported by the PRIME-XS project, grant agreement number 262067, funded by the European Union seventh Framework Programme; The Netherlands Proteomics Centre, embedded in The Netherlands Genomics Initiative; The Netherlands Bioinformatics Centre; and the Centre for Biomedical Genetics (to S.C., B.B. and A.J.R.H); by NIH grants NCRR RR001614 and RR019934 (to the UCSF Mass Spectrometry Facility, director: A.L. Burlingame, P.B.); and by grants from the MRC, CR-UK, BBSRC and Barts and the London Charity (to P.C.
Gastrointestinal nematode infections in German sheep
The objective of the present study was to determine the prevalence and variation of natural gastrointestinal nematode (GIN) infections in lambs according to birth type, gender and breed based on individual faecal egg counts (FEC) from various regions in Germany. A total of 3,924 lambs (3 to 15 months old) with different genetic backgrounds (Merinoland, German Blackhead Mutton, Rhoen, Texel and Merino long-wool) were individually sampled during the grazing period between 2006 and 2008. Furthermore, pooled faecal samples from each of the farms were cultured in order to differentiate the third-stage larvae of the nematode spp. Sixty-three percent of the lambs were infected with GIN. The infections were mostly low to moderate and involved several nematode species. The Trichostrongylus spp. was the predominant species based on the percentage of larvae in faecal cultures. Only 11.4% of the lambs were free of Eimeria oocysts. Tapeworm eggs were encountered in 13.2% of all samples. The prevalence of GIN infections varied significantly (P < 0.001) among farms. A significantly higher FEC (P < 0.05) was observed in multiple-born lambs when compared with singletons. Moreover, male lambs were more susceptible to infection than females (P < 0.001). No significant differences (P > 0.05) were observed between breeds regarding FEC. Inter-individual variations were higher than inter-breed differences, which may indicate the possibility of selection within these breeds for parasites resistance as described in earlier studies
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