Working with Low Survey Response Rates: The Efficacy of Weighting Adjustments

National data show a continuing decline in the willingness of people to respond to surveys. This trend is troubling given the central role that survey research plays in collecting data for institutional research purposes. This paper examines the effectiveness of a weighting procedure described by Astin and Molm for adjusting survey results to correct for nonresponse bias. Using data from a Cooperative Institutional Research Program (CIRP) follow-up survey, the results indicate that the weighting procedure is highly effective at reducing nonresponse bias in univariate distributions. The effectiveness of the weighting procedure in adjusting correlation and regression analyses is less clear. This may be due in part to the observation that even when individual variables are noticeably biased, their relationships with each other tend not to be.     

Rapid determination of erythrocyte sedimentation rate (ESR) by an electrically driven blood droplet biosensor

In healthcare practice, the sedimentation rate of red blood cells (erythrocytes) is a widely used clinical parameter for screening of several ailments such as stroke, infectious diseases, and malignancy. In a traditional pathological setting, the total time taken for evaluating this parameter varies typically from 1 to 2 h. Furthermore, the volume of human blood to be drawn for each test, following a gold standard laboratory technique (alternatively known as the Westergren method), varies from 4 to 5 ml. Circumventing the above constraints, here we propose a rapid (∼1 min) and highly energy efficient method for the simultaneous determination of hematocrit and erythrocyte sedimentation rate (ESR) on a microfluidic chip, deploying electrically driven spreading of a tiny drop of blood sample (∼8 μl). Our unique approach estimates these parameters by correlating the same with the time taken by the droplet to spread over a given radius, reproducing the results from more elaborate laboratory settings to a satisfactory extent. Our novel methodology is equally applicable for determining higher ranges of ESR such as high concentration of bilirubin and samples corresponding to patients with anemia and patients with some severe inflammation. Furthermore, the minimal fabrication steps involved in the process, along with the rapidity and inexpensiveness of the test, render the suitability of the strategy in extreme point-of-care settings.     

TSH Comparison Between Chemiluminescence (Architect) and Electrochemiluminescence (Cobas) Immunoassays: An Indian Population Perspective

Although 3rd generation TSH assays are the most widely used immunoassays, credible comparison studies, specially involving Indian sub-populations are practically non-existent. To compare the TSH measurements between chemiluminescence (Architect) and electrochemiluminescence (Cobas) inmmunoassays in an urban ambulatory Indian population. 1,615 subjects were selected randomly from the usual laboratory workflow, their TSH measured in Architect and Cobas and the paired data thus generated were statistically analysed. TSH values of Cobas were observed to be higher than the Architect values by 28.7 %, with a significant proportional difference between the two, but majority of the Cobas values (above 90 %) were within the limits of agreement with Architect values. In situations where both the instruments are in use simultaneously, a standardization of the methods is imperative, in larger interest of the patient populace.     

Weighing designs to detect a single counterfeit coin

In this article, we discuss at length a combinatorial problem which has been of historic interest. It has appeared as a puzzle in several different versions with varying degrees of difficulty. It can be simply stated as follows: We are given a number of coins which are otherwise identical except that there may be at most one fake coin among them which is either slightly heavier or slightly lighter than the other genuine coins. Using only a two-pan weighing balance, we must devise a weighing scheme to identify the counterfeit coin and determine whether it is heavier or lighter (or declare that all coins are normal). We construct both sequential and non-sequential (that is, simultaneously declared) weighing plans for any given number of coins containing at most one fake coin using the minimum number of weighings needed.     

Usefulness of serum CA 15.3 and histopathological prognostic indices in breast cancer

Prognostic factors influence the modality and course of therapy in breast cancer. These include both histopathological and biochemical variables. This study was aimed to find out if any correlation exists between the biochemical tumor marker-serum CA 15.3, and the lymph node staging of Nottingham’s Prognostic Index (NPI). It was observed that serum CA 15.3 showed a statistically significant correlation with lymph node staging of NPI. Therefore it is concluded that CA 15.3 can be utilized as a useful prognostic marker, particularly in cases where histopathological variables such as tumor size and grade have been altered by pre-operative chemotherapy.     

Correlation between serum lipid profile and carotid intima-media thickness in Polycystic Ovarian Syndrome

Abnormal lipid profile is often found in women with Polycystic Ovary Syndrome. To assess the impact of abnormal lipid profile on atherosclerosis in young Polycystic Ovary Syndrome women, carotid intima-media thickness as judged by B-mode ultrasonography were done in 30 young (18–35 yrs) Polycystic Ovary Syndrome women and in similarly age-matched 30 apparently healthy controls. Compared to controls, young Polycystic Ovary Syndrome women had significantly elevated serum total cholesterol, triglyceride and LDL-C levels and carotid intima-media thickness. HDL-C level did not differ significantly between two groups of women. In Polycystic Ovary Syndrome women carotid intima-media thickness was positively correlated with serum total cholesterol, triglyceride and LDL-C and negatively correlated with serum HDL-C. Our study suggests that even young Polycystic Ovary Syndrome women are prone to atherosclerosis from early age.