A statistical study of mammary vessel after breat cancer surgery

The following statistical study is about a series of quantitative response variables monitored three and six months after a breast operation. All patients that underwent a brest cancer operation from January 2003 untill June 2003 have been enrolled in the study. The number of patients observed is 38, but we have excluded from this study a patient for wich we do not have observed all investigated variables. The main issues involved here are: Descriptive analysis Temporal evolution of phenomena Effects of patient condition on the response variables In the following the three and six months variations of the response variables are labeled as (3) and (6) respectively, while the three to six month variation is marked as (6) (3).

Zero variance in Markov chain Monte Carlo with an application to credit risk estimation

We propose a general purpose variance reduction technique for Markov Chain Monte Carlo estimators based on the Zero-Variance principle introduced in the physics lit- erature by Assaraf and Caarel ( 1999). The potential of the new idea is illustrated with some toy examples and a real application to Bayesian inference for credit risk estimation.Markov chain Monte Carlo, Metropolis-Hastings algorithm, Variance re- duction, Zero-Variance principle.

Bayesian estimate of credit risk via MCMC with delayed rejection

We develop a Bayesian hierarchical logistic regression model to predict the credit risk of companiers classified in different sectors. Explanatory variables derived by experts from balance-sheets are included. Markov chain Monte Carlo (MCMC) methods are used to estimate the proposed model. In particular we show how the delaying rejection strategy outperforms the standart Metrtopolis-Hastings algorithm in terms of asymptotic efficiency of the resulting estimates. The advantages of our over others proposed in the literature are discussed and tested via cross-validation procedures.Asymptotic efficiency of MCMC estimates, Creadit risk, Default risk, Delayng rejection, Hierarchical logistic regression, Metropolis-Hastings algorithm

Variance reduction in MCMC

We propose a general purpose variance reduction technique for MCMC estimators. The idea is obtained by combining standard variance reduction principles known for regular Monte Carlo simulations (Ripley, 1987) and the Zero-Variance principle introduced in the physics literature (Assaraf and Caffarel, 1999). The potential of the new idea is illustrated with some toy examples and an application to Bayesian estimationMarkov chain Monte carlo, Metropolis-Hastings algorithm, Variance reduction, Zero-Variance principle

PM fractional machines adopting bonded magnets: effect of different magnetizations on the energetic performance

The adoption of Permanent Magnets in small brushless machines for automotive applications is becoming frequent. Some research on bonded magnets is being carried on to substitute the ferrites. In the paper the parallel and radial magnetizations are considered: the different process complexity levels are analyzed and the effects on the iron losses and the energetic performances are evaluated by means of a simulation analysis and its experimental validatio

Evaluation of the magnetization direction effects on ferrite PM brushless fractional machines

Permanent magnets are frequently adopted in small brushless machines for automotive applications. Normally anisotropic ferrites, but some research on bonded magnets is being carried on. Several types of magnetization can be proposed, involving different levels of complexity in the magnetization process. In the paper a comparison between parallel and radial magnetization is described, taking into account on one side the major complexity of the radial process and on the other the small power derating of the paralle

Gyrification brain abnormalities as predictors of outcome in anorexia nervosa.

Gyrification brain abnormalities are considered a marker of early deviations from normal developmental trajectories and a putative predictor of poor outcome in psychiatric disorders. The aim of this study was to explore cortical folding morphology in patients with anorexia nervosa (AN). A MRI brain study was conducted on 38 patients with AN, 20 fully recovered patients, and 38 healthy women. Local gyrification was measured with procedures implemented in FreeSurfer. Vertex-wise comparisons were carried out to compare: (1) AN patients and healthy women; (2) patients with a full remission at a 3-year longitudinal follow-up assessment and patients who did not recover. AN patients exhibited significantly lower gyrification when compared with healthy controls. Patients with a poor 3-year outcome had significantly lower baseline gyrification when compared to both healthy women and patients with full recovery at follow-up, even after controlling for the effects of duration of illness and gray matter volume. No significant correlation has been found between gyrification, body mass index, amount of weight loss, onset age, and duration of illness. Brain gyrification significantly predicted outcome at follow-up even after controlling for the effects of duration of illness and other clinical prognostic factors. Although the role of starvation in determining our findings cannot be excluded, our study showed that brain gyrification might be a predictor of outcome in AN. Further studies are needed to understand if brain gyrification abnormalities are indices of early neurodevelopmental alterations, the consequence of starvation, or the interaction between both factors

Linguistic embodiment in typical and atypical anorexia nervosa: Evidence from an image-word matching task

Objective: The integration of sensory, motor, and cognitive systems is embodied cognition, according to which mind and body are not separate and distinct, and our body (and our brain, as part of the body) contributes to determining our mental and cognitive processes. In spite of limited data available, Anorexia nervosa (AN) appears as a condition in which embodied cognition is altered, in particular, if we consider bodily sensations and visuospatial information processing. We aimed to evaluate the ability to correctly identify body parts and actions in both full (AN) and atypical AN (AAN), looking at the role of the underweight status. Method: A group of 143 females (AN = 45, AAN = 43, unaffected women = 55) was enrolled. All participants performed a linguistic embodied task to evaluate the association between a picture-showing a bodily action-and a written verb. Additionally, a subsample of 24 AN participants performed a retest after stable weight recovery. Results: Both AN and AAN demonstrated an abnormal ability to evaluate the picture-written verb associations, especially if the involved bodily effectors were the same in both stimuli (i.e., pictorial and verbal) and needed a longer response time. Conclusions: Specific embodied cognition linked to body schema seems to be impaired in persons with AN. The longitudinal analysis showed a difference between AN and AAN only in the underweight condition, suggesting the presence of an abnormal linguistic embodiment. More attention should be devoted to embodiment during AN treatment to improve bodily cognition, which might, in turn, diminish body misperception

The Mice Drawer System (MDS) Experiment and the Space Endurance Record-Breaking Mice

The Italian Space Agency, in line with its scientific strategies and the National Utilization Plan for the International Space Station (ISS), contracted Thales Alenia Space Italia to design and build a spaceflight payload for rodent research on ISS: the Mice Drawer System (MDS). The payload, to be integrated inside the Space Shuttle middeck during transportation and inside the Express Rack in the ISS during experiment execution, was designed to function autonomously for more than 3 months and to involve crew only for maintenance activities. In its first mission, three wild type (Wt) and three transgenic male mice over-expressing pleiotrophin under the control of a bone-specific promoter (PTN-Tg) were housed in the MDS. At the time of launch, animals were 2-months old. MDS reached the ISS on board of Shuttle Discovery Flight 17A/STS-128 on August 28th, 2009. MDS returned to Earth on November 27th, 2009 with Shuttle Atlantis Flight ULF3/STS-129 after 91 days, performing the longest permanence of mice in space. Unfortunately, during the MDS mission, one PTN-Tg and two Wt mice died due to health status or payload-related reasons. The remaining mice showed a normal behavior throughout the experiment and appeared in excellent health conditions at landing. During the experiment, the mice health conditions and their water and food consumption were daily checked. Upon landing mice were sacrificed, blood parameters measured and tissues dissected for subsequent analysis. To obtain as much information as possible on microgravity-induced tissue modifications, we organized a Tissue Sharing Program: 20 research groups from 6 countries participated. In order to distinguish between possible effects of the MDS housing conditions and effects due to the near-zero gravity environment, a ground replica of the flight experiment was performed at the University of Genova. Control tissues were collected also from mice maintained on Earth in standard vivarium cages

Does social cognition change? Evidence after 4 years from the Italian Network for Research on Psychoses

BackgroundDeficits in social cognition (SC) are significantly related to community functioning in schizophrenia (SZ). Few studies investigated longitudinal changes in SC and its impact on recovery. In the present study, we aimed: (a) to estimate the magnitude and clinical significance of SC change in outpatients with stable SZ who were assessed at baseline and after 4 years, (b) to identify predictors of reliable and clinically significant change (RCSC), and (c) to determine whether changes in SC over 4 years predicted patient recovery at follow-up. MethodsThe reliable change index was used to estimate the proportion of true change in SC, not attributable to measurement error. Stepwise multiple logistic regression models were used to identify the predictors of RCSC in a SC domain (The Awareness of Social Inference Test [TASIT]) and the effect of change in TASIT on recovery at follow-up. ResultsIn 548 participants, statistically significant improvements were found for the simple and paradoxical sarcasm of TASIT scale, and for the total score of section 2. The reliable change index was 9.8. A cut-off of 45 identified patients showing clinically significant change. Reliable change was achieved by 12.6% and RCSC by 8% of participants. Lower baseline TASIT sect. 2 score predicted reliable improvement on TASIT sect. 2. Improvement in TASIT sect. 2 scores predicted functional recovery, with a 10-point change predicting 40% increase in the probability of recovery. ConclusionsThe RCSC index provides a conservative way to assess the improvement in the ability to grasp sarcasm in SZ, and is associated with recovery