400 research outputs found

    OPTIMIST: A new conflict resolution algorithm for ACT-R.

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    Several studies have suggested recently that a more dynamic conflict resolution mechanism in the ACT-R cognitive architecture (Anderson & Lebiere, 1998) could improve the decision-making behaviour of cognitive models. This part of ACT-R theory is revisited and a new solution is proposed. The new algorithm (OPTIMIST) has been implemented as an overlay to the ACT-R architecture, and can be used as an alternative mechanism. The operation of the new algorithm is tested in a model of the classical Yerkes and Dodson experiement of animals' learning. When OPTIMIST is used, the resulting model fits the data better than the previous model (e.g. R2 (R squared) increases from .85 to .93 in one example)

    Analysis of health care and actual needs of patients with psoriasis: a survey on the Italian population

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    Background: Over recent years the public health system has shown increasing interest in patients' views for use as guideline criteria in evaluating the quality of assistance above all for those patients with chronic diseases. Hence the interest in psoriasis, which is a chronic disease frequently associated with diabetes mellitus, hypertension, obesity, and cardiovascular diseases. The aims of our study were to describe clinic characteristics of patients with psoriasis, the quality of the assistance perceived by patients arrived at outpatients clinics and the information received, in order to identify areas in Italy requiring improvement. Methods: 1954 patients, aged between 18 and 85 years, were consecutively enrolled at outpatients clinics across 21 Italian provinces over the period December 2004 - January 2006. A standardized questionnaire was developed in collaboration with an Italian Association of Psoriatic Patients ( A. DI. PSO) and tested in a pilot study. The questionnaire was divided into three sections: the first section included social, demographic and individual variables; the second concerned the quality of the assistance perceived by the patients at public dermatologic clinics and the third focused on the need of information requirements of patients with psoriasis. The chi(2) test was used to estimate the association between the categorical variables under study. Kruskal-Wallis test was applied to the interval and ordinal variables. Results: The presence of psoriatic arthritis was reported in 26.0% of patients. Associated chronic diseases included depression (15.4%), hypertension (13.3%), obesity (8.9%) and type 2 diabetes mellitus (7.3%). The study highlighted the need of improvements of health care services at public dermatologic clinics especially in overcoming architectonic barriers and reducing appointment wait-times, particularly in South Italy. However, patients reported a positive relationship with Health System employers due to the confidentiality. This positive impression was confirmed by the observation that dermatologists were considered the best source of information about therapies on psoriasis. Conclusion: Our study allowed to identify critical aspects which could be tackled through initiatives with the aim of improving these emerged needs

    Stem cell therapies for ischemic cardiovascular diseases

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    Myocardial infarction results in loss of cardiac muscle and deficiency in cardiac performance. Likewise, peripheral artery disease can result in critical limb ischemia leading to reduced mobility, non-healing ulcers, gangrene and amputation. Both of these common conditions diminish quality of life and enhance risk of mortality. Successful advances in treatment have led to more people surviving incidences of myocardial infarction or living with peripheral artery disease. However, the current treatments are inadequate in repairing ischemic tissue. Over the last 5 years, a vast number of patents have been submitted concerning the use of stem cells, which correlates with the exponential growth in stem cell publications. Exploiting stem cell therapy offers a real potential in replacing ischemic tissue with functional cells. In this paper, we review recent patents concerning stem cell therapy that have the potential to provide or potentiate novel treatment for ischemic cardiovascular disease. In addition, we evaluate the promise of the inventions by describing some clinical trials that are currently taking place, as well as considering how current research on ischemic cardiovascular disease may change the patent landscape in the future

    ParkDB: a Parkinson's disease gene expression database

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    Parkinson's disease (PD) is a common, adult-onset, neuro-degenerative disorder characterized by the degeneration of cardinal motor signs mainly due to the loss of dopaminergic neurons in the substantia nigra. To date, researchers still have limited understanding of the key molecular events that provoke neurodegeneration in this disease. Here, we present ParkDB, the first queryable database dedicated to gene expression in PD. ParkDB contains a complete set of re-analyzed, curated and annotated microarray datasets. This resource enables scientists to identify and compare expression signatures involved in PD and dopaminergic neuron differentiation under different biological conditions and across species. Database URL: http://www2.cancer.ucl.ac.uk/Parkinson_Db2

    Accuracy of elastic fusion biopsy in daily practice: results of a multicenter study of 2115 patients

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    OBJECTIVES: To assess the accuracy of Koelis fusion biopsy for the detection of prostate cancer and clinically significant prostate cancer in the everyday practice. METHODS: We retrospectively enrolled 2115 patients from 15 institutions in four European countries undergoing transrectal Koelis fusion biopsy from 2010 to 2017. A variable number of target (usually 2-4) and random cores (usually 10-14) were carried out, depending on the clinical case and institution habits. The overall and clinically significant prostate cancer detection rates were assessed, evaluating the diagnostic role of additional random biopsies. The cancer detection rate was correlated to multiparametric magnetic resonance imaging features and clinical variables. RESULTS: The mean number of targeted and random cores taken were 3.9 (standard deviation 2.1) and 10.5 (standard deviation 5.0), respectively. The cancer detection rate of Koelis biopsies was 58% for all cancers and 43% for clinically significant prostate cancer. The performance of additional, random cores improved the cancer detection rate of 13% for all cancers (P < 0.001) and 9% for clinically significant prostate cancer (P < 0.001). Prostate cancer was detected in 31%, 66% and 89% of patients with lesions scored as Prostate Imaging Reporting and Data System 3, 4 and 5, respectively. Clinical stage and Prostate Imaging Reporting and Data System score were predictors of prostate cancer detection in multivariate analyses. Prostate-specific antigen was associated with prostate cancer detection only for clinically significant prostate cancer. CONCLUSIONS: Koelis fusion biopsy offers a good cancer detection rate, which is increased in patients with a high Prostate Imaging Reporting and Data System score and clinical stage. The performance of additional, random cores seems unavoidable for correct sampling. In our experience, the Prostate Imaging Reporting and Data System score and clinical stage are predictors of prostate cancer and clinically significant prostate cancer detection; prostate-specific antigen is associated only with clinically significant prostate cancer detection, and a higher number of biopsy cores are not associated with a higher cancer detection rate

    Long-term outcome of epilepsy in patients with prader–willi syndrome

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    Prader-Willi syndrome is a multisystemic genetic disorder that can be associated with epilepsy. There is insufficient information concerning the clinical and electroencephalographic characteristics of epilepsy and the long-term outcome of these patients. The aim of this study is to describe seizure types, electroencephalographic patterns and long-term seizure outcome in Prader-Willi syndrome patients suffering from epilepsy. We retrospectively studied 38 patients with Prader-Willi syndrome and seizures. Results of neuroimaging studies were obtained for 35 individuals. We subdivided these patients into two groups: group A, 24 patients, without brain lesions; and group B, 11 patients, with brain abnormalities. All patients were re-evaluated after a period of at least 10 years. Twenty-one patients (55.2 %) were affected by generalized epilepsy and 17 patients (44.8 %) presented focal epilepsy. The most common seizure type was generalized tonic-clonic seizure. The mean age at seizure onset was 4.5 years (ranged from 1 month to 14 years). In the follow-up period, seizure freedom was achieved in 32 patients (84.2 %). Seizure freedom was associated with electroencephalographic normalization, while the six children presenting drug-resistant epilepsy showed persistence of electroencephalographic abnormalities. Group B patients showed a higher prevalence of drug-resistant epilepsy. Patients with Prader-Willi syndrome were frequently affected by generalized seizures. Most of the patients had a favorable evolution, although, patients with brain abnormalities presented a worse outcome, suggesting that the presence of these lesions can influence the response to antiepileptic therapy.Prader–Willi syndrome is a multisystemic genetic disorder that can be associated with epilepsy. There is insufficient information concerning the clinical and electroencephalographic characteristics of epilepsy and the long-term outcome of these patients. The aim of this study is to describe seizure types, electroencephalographic patterns and long-term seizure outcome in Prader–Willi syndrome patients suffering from epilepsy. We retrospectively studied 38 patients with Prader–Willi syndrome and seizures. Results of neuroimaging studies were obtained for 35 individuals. We subdivided these patients into two groups: group A, 24 patients, without brain lesions; and group B, 11 patients, with brain abnormalities. All patients were re-evaluated after a period of at least 10 years. Twenty-one patients (55.2 %) were affected by generalized epilepsy and 17 patients (44.8 %) presented focal epilepsy. The most common seizure type was generalized tonic– clonic seizure. The mean age at seizure onset was 4.5 years (ranged from 1 month to 14 years). In the follow-up period, seizure freedom was achieved in 32 patients (84.2 %). Seizure freedom was associated with electroencephalographic normalization, while the six children presenting drug-resistant epilepsy showed persistence of electroencephalographic abnormalities. Group B patients showed a higher prevalence of drug-resistant epilepsy. Patients with Prader–Willi syndrome were frequently affected by generalized seizures. Most of the patients had a favorable evolution, although, patients with brain abnormalities presented a worse outcome, suggesting that the presence of these lesions can influence the response to antiepileptic therapy

    Galileo dust data from the jovian system: 2000 to 2003

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    The Galileo spacecraft was orbiting Jupiter between Dec 1995 and Sep 2003. The Galileo dust detector monitored the jovian dust environment between about 2 and 370 R_J (jovian radius R_J = 71492 km). We present data from the Galileo dust instrument for the period January 2000 to September 2003. We report on the data of 5389 particles measured between 2000 and the end of the mission in 2003. The majority of the 21250 particles for which the full set of measured impact parameters (impact time, impact direction, charge rise times, charge amplitudes, etc.) was transmitted to Earth were tiny grains (about 10 nm in radius), most of them originating from Jupiter's innermost Galilean moon Io. Their impact rates frequently exceeded 10 min^-1. Surprisingly large impact rates up to 100 min^-1 occurred in Aug/Sep 2000 when Galileo was at about 280 R_J from Jupiter. This peak in dust emission appears to coincide with strong changes in the release of neutral gas from the Io torus. Strong variability in the Io dust flux was measured on timescales of days to weeks, indicating large variations in the dust release from Io or the Io torus or both on such short timescales. Galileo has detected a large number of bigger micron-sized particles mostly in the region between the Galilean moons. A surprisingly large number of such bigger grains was measured in March 2003 within a 4-day interval when Galileo was outside Jupiter's magnetosphere at approximately 350 R_J jovicentric distance. Two passages of Jupiter's gossamer rings in 2002 and 2003 provided the first actual comparison of in-situ dust data from a planetary ring with the results inferred from inverting optical images.Comment: 59 pages, 13 figures, 6 tables, submitted to Planetary and Space Scienc

    Exercise promotes angiogenesis and improves beta-adrenergic receptor signalling in the post-ischaemic failing rat heart.

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    We investigated whether exercise training could promote angiogenesis and improve blood perfusion and left ventricular (LV) remodelling of the post-myocardial infarction (MI) failing heart. We also explored the contribution of ameliorated beta-adrenergic receptor signalling and function on the overall improvement of cardiac contractility reserve induced by exercise.Adult Wistar male rats were randomly assigned to one of four experimental groups. Sham-operated and post-MI heart failure (HF) rats were housed under sedentary conditions or assigned to 10-weeks of a treadmill exercise protocol. At 4 weeks after MI, sedentary HF rats showed LV eccentric hypertrophy, marked increase of LV diameters associated with severely impaired fractional shortening (14 +/- 5\%), increased LV end diastolic pressure (20.9 +/- 2.6 mmHg), and pulmonary congestion. In addition, cardiac contractile responses to adrenergic stimulation were significantly blunted. In trained HF rats, exercise was able to (i) reactivate the cardiac vascular endothelial growth factor pathway with a concurrent enhancement of myocardial angiogenesis, (ii) significantly increase myocardial perfusion and coronary reserve, (iii) reduce cardiac diameters, and (iv) improve LV contractility in response to adrenergic stimulation. This latter finding was also associated with a significant improvement of cardiac beta-adrenergic receptor downregulation and desensitization.Our data indicate that exercise favourably affects angiogenesis and improves LV remodelling and contractility reserve in a rat model of severe chronic HF
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