Soft and Hard Iron Compensation for the Compasses of an Operational Towed Hydrophone Array without Sensor Motion by a Helmholtz Coil.

Usually, towed hydrophone arrays are instrumented with a set of compasses. Data from these sensors are utilized while beamforming the acoustic signal for target bearing estimation. However, elements of the hydrophone array mounted in the neighborhood of a compass can affect the Earth's magnetic field detection. The effects depend upon the materials and magnetic environment present in the vicinity of the platform hosting the compass. If the disturbances are constant in time, they can be compensated for by means of a magnetic calibration procedure. This process is commonly known as soft and hard iron compensation. In this paper, a solution is presented for carrying out the magnetic calibration of a COTS (Commercial Off the Shelf) digital compass without sensor motion. This approach is particularly suited in applications where a physical rotation of the platform that hosts the sensor is unfeasible. In our case, the platform consists in an assembled and operational towed hydrophone array. A standard calibration process relies on physical rotation of the platform and thus on the use of the geomagnetic field as a reference during the compensation. As a variation on this approach, we generate an artificial reference magnetic field to simulate the impractical physical rotation. We obtain this by using a tri-axial Helmholtz coil, which enables programmability of the reference magnetic field and assures the required field uniformity. In our work, the simulated geomagnetic field is characterized in terms of its uncertainty. The analysis indicates that our method and experimental set-up represent a suitably accurate approach for the soft and hard iron compensation of the compasses equipped in the hydrophone array under test.

The impact of colorectal screening program on the detection of right-sided colorectal cancer. A 5-year cohort study in the Mantua District.

BACKGROUND: High rates of advanced colorectal cancer (CRC) are still diagnosed in the right side of the colon. This study aimed to investigate whether screening programs increase CRC detection and whether tumor location is associated with survival outcome. METHODS: Patients affected by CRC, aged from 50 to 69 years and operated on from 2005 to 2009 were reviewed. Other than patient-, disease-, and treatment-related factors, detection mode and tumor location were recorded. Overall (OS) and disease-free survival (DFS) were investigated, using univariate and multivariate analyses. RESULTS: Mean age of 386 patients included was 62.0 years, 59 % were males. CRC was detected by screening in 17 % of cases, and diagnosis was made from symptoms in 67 % and emergency surgery for 16 %. Screen-detected CRCs were located in the left colon (59 %), then in rectum (25 %) and in proximal colon (16 %) (p = 0.02). Most of CRC patients urgently operated on had cancer located in proximal colon (45 %), then in the left colon (36 %) and in rectum (18 %) (p = 0.001). Right-sided CRC demonstrated higher pTNM stage (p = 0.001), adequate harvest count nodes (p = 0.0001), metastatic nodes (p = 0.02), and poor differentiation grading (p = 0.0001). With multivariate analysis, poor differentiation grade was independently associated with both worse OS (HR 3.6, p = 0.05) and worse DFS (HR 8.1, p = 0.0001), while distant recurrence was associated with worse OS (HR 20.1, p = 0.0001). CONCLUSION: Low rates of right-sided CRC are diagnosed following screening program. Proximal CRC demonstrates aggressive behavior without impact on outcome. These findings prompt concern about population awareness for CRC screening.

Ranking COMMPS chemical substances by an improved POT/RLE approach.

The combined monitoring-based and modeling-based priority setting (COMMPS) provides a procedure for the identification of priority hazardous substances outlined in the Working Document (ENV/191000/01 of January 16, 2001). This procedure is based on scoring a set of criteria which individually make substances more or less hazardous. The way scores are weighted and combined has been established by a panel of experts. Different authors outlined how such a procedure might be affected by subjectiveness of judgment, and alternative solutions based on partial order theory (POT) and random linear extensions (RLE) have been suggested. This method consists of generating a set of RLE and of averaging the rank given to each substance, so that a total order could be determined. Any POT/RLE approach must face the issue of covering as much as possible the space of linear extensions that, in the case of the 85 substances considered by COMMPS, becomes extremely large, and an exhaustive generation of linear extension is not feasible. Therefore, having a faster algorithm would help to consider a larger number of linear extensions in a given time frame. In this paper, we discuss this problem, and we outline a possible solution.

A validation study regarding a generative approach in choosing appropriate colors for impaired users.

In many circumstances, concepts, ideas and emotions are mainly conveyed by colors. Color vision disorders can heavily limit the user experience in accessing Information Society. Therefore, color vision impairments should be taken into account in order to make information and services accessible to a broader audience. The task is not easy for designers that generally are not affected by any color vision disorder. In any case, the design of accessible user interfaces should not lead to to boring color schemes. The selection of appealing and harmonic color combinations should be preserved. In past research we investigated a generative approach led by evolutionary computing in supporting interface designers to make colors accessible to impaired users. This approach has also been followed by other authors. The contribution of this paper is to provide an experimental validation to the claim that this approach is actually beneficial to designers and users.

Postpartum urinary symptoms: prevalence and risk factors.

OBJECTIVES: To assess the prevalence of urinary symptoms, the relationship between urinary symptoms and vaginal descent, and the association between urinary symptoms and obstetric factors. STUDY DESIGN: Five hundred and thirty-seven women were interviewed and underwent a urogynaecological evaluation 3 months after vaginal delivery. Quantitative-type variables were subjected to Student's t test. Simple logistic regression analyses were carried out on the symptoms studied as a function of risk factors. RESULTS: 8.2% of primiparae showed stress urinary incontinence and multiparae in 20% (P=0.0001); urge incontinence was present in 5.5% of primiparae and in 13% of multiparae (P=0.004). Significant correlations were found among operative vaginal delivery, dysuria (P=0.048) and frequency (P=0.036). Urinary incontinence appeared associated with induced labour with prostaglandins (P=0.018) and with general maternal factors, such as parity (P=0.001) and elevated weight at the beginning of pregnancy (P=0.019). CONCLUSIONS: It is likely that the pathogenesis of postpartum urinary incontinence includes not only the effects of pelvic floor trauma on urethrovesical mobility under stress, but also a deficiency in urethral resistance caused by drugs, such as prostaglandins.

Perineal ultrasound evaluation of urethral angle and bladder neck mobility in women with stress urinary incontinence.

OBJECTIVES: 1. To assess the reproducibility of an electronic ultrasonographic technique for the measurement of urethral angulation; 2. to test the ability of measurement of the urethral angle and bladder neck mobility to predict genuine stress incontinence; 3. to compare ultrasound variables in stress incontinent women and in controls. DESIGN: Case-control study. POPULATION: Twenty-three incontinent women and 50 controls. METHODS: Electronic measurements of the distance between the bladder neck and the symphysis pubis, the bladder neck and the symphysis pubis line and the midline of the symphysis (alpha angle) and the angle between the proximal and distal urethra (beta angle) by means of perineal ultrasonography with a comfortably full bladder at rest, during the Valsalva manoeuvre and during maximal pelvic floor contraction. The same procedure was performed by a second investigator. Repeatability was evaluated by the technique described by Bland and Altman. Statistical analysis was performed using Student's t test and the two-tailed paired t test. MAIN OUTCOME MEASURES: To test the possible role of the urethral angle in maintaining female continence. RESULTS: Ultrasound analysis showed good repeatability between the two observers and is not influenced by vesical volume. Beta angle and urethrovesical mobility are inversely proportional, both in continent and in incontinent women. Urethral angle identifies genuine stress incontinence better than urethrovesical mobility (sensitivity 96% vs 87%; specificity 92% vs 68%; positive predictive value 85% vs 55%). There are significant differences in all ultrasound variables between incontinent women and continent controls. CONCLUSIONS: This study suggests a significant role of the urethral angle in maintaining female continence (in incontinent women it is lower at rest and lowers with straining). Measurement of the urethral angle can provide useful additional information to that provided by ultrasound evaluation of bladder neck mobility.