Skewed Population Research Articles

Health delivery system for older adults in academic campus in India

PurposeResidential academic campuses generally support a skewed population profile that favours a younger population, mainly the student community, and thereby marginalize the needs of the older people staying within the campus. Health delivery systems are often not in accordance with the needs of staff members co-habiting with their aged parents and relatives as well as older staff members themselves. This poses a serious problem, especially in India, where filial piety is a norm and many employees cohabit with their parents. Moreover, the Government of India has reformulated its retirement policy under which the age for superannuation of teaching staff has been enhanced. This in turn, has raised the older-younger ratio in campuses in recent years. The paper aims to discuss these issues.Design/methodology/approachTo address these issues, a household survey was carried out on older people staying in a residential academic campus of India followed by a focus group discussion with family caregivers of the older people.FindingsIt was found that older people were a marginalized group in campus, as health delivery system and allied facilities were not consistent with their needs. As a result, they and their family caregivers faced various challenges.Originality/valueThis is the first study exploring the possibility of academic campuses in India to emerge as alternate sites for supporting older care.

QOLP-39. UNRAVELING THE TRUE COST OF CARE THROUGH ANALYSIS OF THE SOCIOECONOMIC IMPACT OF GLIOMA SURVIVORSHIP

Abstract BACKGROUND There is a paucity of data describing the socioeconomic impact and long-term implications of glioma survivorship. Objective: To characterize the socioeconomic impact of glioma survivorship using the standardized Medical Expenditure Panel Survey – Household Component (MEPS-HC). METHODS 89 of 107 eligible adult glioma survivors that were post-treatment with stable disease were enrolled. The MEPS-HC was utilized to assess the socioeconomic hardship referable to the patient’s tumor. Comparisons between groups were evaluated using a Fisher’s exact test. RESULTS 89 patients responded to the survey (response rate = 85%, female =52%). Median follow-up from diagnosis was 6.0 years (4.3, 9.2). Pathology at diagnosis was high-grade (40%) and low-grade (60. The majority of glioma survivors were insured (91%), employed (79%), and reported annual household incomes slightly above national average. Nearly a quarter incurred debt because of their tumor (24%), 53% required extended unpaid time off, and 46% retired or were no longer working. While 85% had a Karnofsky Performance Score of > 90, the majority of respondents reported lost productivity and decreased ability to perform cognitive and physical tasks (69%). Financial burden and workforce morbidity were insensitive to tumor location, laterality, and annual household income. Patients with a gross-total resection (GTR) at initial surgery were less likely to report ongoing limitations in daily activities (45% v. 83%, p=0.004). CONCLUSIONS Despite the skewed population of high-functioning glioma survivors, financial burden and workforce morbidity was ubiquitous across all tumor subtypes, treatment paradigms, and income levels. Those with GTR were less likely to report ongoing limitations. There was a trend towards greater financial burden among those with frontal and temporal lesions.

Robotic proctectomy for rectal cancer in the US: a skewed population.

Socioeconomic and racial differences have been associated with disparities in cancer care within the US, including disparate access to minimally invasive surgery for rectal cancer. We hypothesized that robotic approach to rectal cancer may be associated with similar disparities. The National Cancer Database (NCDB) was used to identify patients over 18years old with clinical stage I-III rectal adenocarcinoma who underwent a proctectomy between 2010 and 2014. Demographic and hospital factors were analyzed for association with robotic approach. Factors identified on bivariate analyses informed multivariate analysis. We identified 33,503 patients who met inclusion criteria; 3702 (11.1%) underwent robotic surgery with 7.8% conversion rate. Patients who received robotic surgery were more likely to be male, white, privately insured and with stage III cancer. They were also more likely to live in a metropolitan area, more than 25 miles away from the hospital and with a higher high school graduation rate. The treating hospital was more likely to be academic and high volume. Robotic surgery is performed rarely and access to it is limited for patients who are female, black, older, non-privately insured and unable to travel to high-volume teaching institutions. The advantages of robotic surgery may not be available to all patients given disparate access to the robot. This inherent bias in access to robot may skew study populations, preventing generalizability of robotic surgery research.

Abstract 4723: Combinatorial efficacy of anti-PD1 treatment and selective histone deacetylase 6 (HDAC6) inhibition in chronic lymphocytic leukemia (CLL)

Abstract A suppressive microenvironment allows CLL B cells to avoid immune surveillance. Coinhibitory antigens, anti-inflammatory cytokines and skewed immune populations support malignancy and contribute to poorer immune responses in CLL patients. Novel approaches to counter immunosuppression are therefore being explored. The HDAC family of proteins epigenetically regulate immune-related pathways in cancer and may be noteworthy immunomodulatory targets. In addition to the recognized role of HDACs in cell survival, HDACi may alter inflammatory status of immune and tumor cells. We have previously reported that HDAC6 regulates IL-10 transcription, and is responsible for T cell anergy in murine and human APCs. IL-10 is secreted by CLL B cells and is thought to influence immunosuppression. Therefore, we hypothesized that HDAC6i could reverse immunosuppression in CLL for antitumor benefit. The purpose of this study was to determine 1) the effects of selective HDAC6i on CLL immune biology and 2) whether combination with HDAC6i could improve efficacy of anti-PD1 for CLL therapy. To accomplish these aims, the euTCL1 and euTCL1/HDAC6KO adoptive transfer models of murine CLL were utilized. ACY738 (selective HDAC6i) was administered orally in chow at 25mpk daily. Anti-PD1 was administered intraperitoneally 3x per week at 3mpk. CLL surface antigens were analyzed via flow cytometry. Functional mixed lymphocyte assays were performed ex vivo, measuring IFNg production, and Th1/Th2 factors were examined via qRT-PCR in CLL T cells. Early PD-L1 expression on B cells correlated to CLL burden in euTCL1 mice. Post ACY738 treatment, euTCL1 B cells downregulated expression of PD-L1 and plasma IL-10. In addition, PD-1 and CTLA4 was decreased on CD4+, CD8+, Tregs and effector memory T cells. Splenic T cells from ACY738 mice upregulated TBET and downregulated GATA3, indicative of a less exhausted phenotype. Subsequently, euTCL1 B cells were treated ex vivo with ACY738 and cocultured with T cells. T cell activation (IFNg production) was increased after coculture with treated B cells compared to control B cells. We then hypothesized that ACY738 could be rationally be combined with anti-PD1 mAb for CLL treatment. Mice treated with anti-PD1 accumulated fewer CD5+ B cells, confirming that PD-1/PD-L1 blockade demonstrated anti-CLL benefit. Strikingly, combination of ACY738 and anti-PD1 further delayed the growth of CLL cells compared to either single agent. Consistently, anti-PD1 treatment in euTCL1/HDAC6KO mice further delayed CLL development. In conclusion, we report here that HDAC6i can reinvigorate CLL T cells, and combination of HDAC6i with anti-PD1 increased anti-CLL efficacy in vivo. This work provides evidence that this combination could be clinically investigated to simultaneously reduce tumor burden and improve immune function in CLL patients. Citation Format: Kamira Maharaj, John Powers, Alex Achille, Eva Sahakian, Javier Pinilla-Ibarz. Combinatorial efficacy of anti-PD1 treatment and selective histone deacetylase 6 (HDAC6) inhibition in chronic lymphocytic leukemia (CLL) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4723.

Functional characteristics of circulating granulocytes in severe congenital neutropenia caused by ELANE mutations

BackgroundNeutrophils and eosinophils are multifunctional granulocytes derived from common myelocytic-committed progenitor cells. Severe congenital neutropenia 1 (SCN1) caused by ELANE mutations is a rare disease characterized by very low numbers of circulating neutrophils. Little is known about the functional characteristics of the SCN1 granulocytes, except that eosinophilia has been noticed in both bone marrow and peripheral blood. In this study, we profiled the number and function of granulocytes in patients suffering from SCN1.MethodsNine patients diagnosed with SCN1 were enrolled in this study and absolute counts of eosinophils and neutrophils from bone marrow aspirates and peripheral blood samples were analysed. In addition, Ficoll-Paque enriched granulocytes from patients and healthy controls were analysed for specific eosinophil and neutrophil markers using flow cytometry and for NADPH-oxidase activity-profile by chemiluminescence.ResultsOur data demonstrate a skewed granulocyte population in SCN1 patients dominated by eosinophils in both bone marrow and peripheral blood. The latter was detected only by blood smear examination, but not by automated blood analysers. Furthermore, we show that the SCN1 eosinophils exerted normal production of reactive oxygen species generated by the NADPH-oxidase, however the response was profoundly different from that of healthy control neutrophils.ConclusionsSCN1 patients with ELANE mutations suffer from neutropenia yet display eosinophilia in the bone marrow and blood, as revealed by smear examination but not by automatic blood analysers. The SCN1 eosinophils are functionally normal regarding production of reactive oxygen species (ROS). However, the ROS profile produced by eosinophils differs drastically from that of neutrophils isolated from the same blood donor, implying that the eosinophilia in SCN1 cannot compensate for the loss of neutrophils regarding ROS-mediated functions.

Should Clinicians' Predicted Imminent and Within 90 days Death be Excluded in Clinical Trials?

Introduction: Excluding patients from clinical trials based on “likely death within 24 hours” and “likely death within 90 days” is common practice. However, inaccurate identification of these patients may lead to skewed trial populations and underpowered studies.

Maternal nesting behaviour in city dragons: a species with temperature-dependent sex determination

Abstract Urban environments present some of the greatest challenges to species survival. This is particularly true for species that exhibit thermally sensitive traits, such as temperature-dependent sex determination (TSD). This is because urban environments not only present species with entirely novel ecosystems, but species will also experience increased temperatures. These temperature increases may result not only in offspring mortality, but also skewed population sex ratios. To persist in cities, urban dwellers with TSD will therefore need to adjust the temperature of the nesting environment, either through phenotypic plasticity or rapid evolution through natural selection. Here, we investigate the nesting ecology of a long-lived, urban dwelling reptile, the eastern water dragon (Intellagama lesueurii), to understand how a TSD species may respond to urban environments. Based on data collected from 72 nests over 2 nesting seasons, we show that city dragons not only dug significantly deeper nests than previously observed across their natural riparian habitat, but also nested in novel substrates. Furthermore, we observed a behaviour not previously described in this species, where mothers travel outside of their core home range to nest. This excursion behaviour potentially represents a greater maternal investment and is linked to the selection of specific microhabitats.

Low Dose Umbilical Cord Blood Transplant Results in Skewed Immune Cell Composition Which May Impact Immune Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation

IntroductionReconstitution of donor-derived immune system after allogeneic hematopoietic stem cell transplantation (HSCT) is essential for recovery and long-term survival. Despite routine use of human umbilical cord blood (hUCB) as a stem cell source for allogeneic HSCT, much remains unknown regarding the kinetics of immune recovery and correlation with different transplant cell dosages. To study the hUCB repopulating potential, different hUCB CD34+ cell dosages were transplanted into immune deficient NSG mice; hematopoietic cells were then collected and engraftment was analyzed.MethodsNOD/SCID/IL-2Rγnull recipient (NSG) mice (Jackson Laboratories, Bar Harbor, ME) were kept in pathogen-free facilities. CD34+ cells were isolated from a pool of six hUCB donors using a CD34+ microbead kit (Miltenyi Biotec). Each sublethal irradiated (220 or 300 cGy) 8 week old female NSG mice received either low dose (15x103, N=15) or high dose (75x103, N=15) CD34+ cells transplanted intravenously via retro-orbital route. Animal experiments were performed in accordance with Institutional Animal Care and Use Committee guidelines. Statistical analysis was performed with Prism software (GraphPad Software, Inc) and Excel. Data are presented as mean ± standard error of the mean (SEM).ResultsTo determine the effects of hUCB CD34+ cell dosages on the rate of engraftment, NSG mice were transplanted with low doseor high dose CD34+ cells. The transplanted CD34+ cell dosages were comparable to clinical dosages based on body weight (Mavroudis et al. 1996). The engrafted cells were analyzed for expression of surface markers that define human hematopoietic cells. During the follow up period of up to 18 weeks, the high dose infused group had increased hUCB engraftment compared with the low dose infused group in peripheral blood (Fig 1A), bone marrow (Fig 1B & 1C) and spleen (Fig 1D), which is consistent with reported clinical observations that infused cell dosage is inversely correlated with time to engraftment (Migliaccio et al. 2000 Blood). Interestingly, we observed different lymphoid subset frequencies between low and high dose infused groups at the post-engraftment stage (18 weeks post transplantation) (data not shown).To investigate different lymphoid subset engraftment frequencies in low and high dose hUCB transplanted recipient mice at early engraftment stage, peripheral blood and hematopoietic organs were collected and analyzed up to 10 weeks post transplantation. The low dose infused group had significantly lower CD3+ (T cells) and CD56+ (NK cells) frequency in peripheral blood at 4 and 8 weeks (Fig 2A & 3A). More importantly, CD3+ (T cells) frequency was close to non-detectable in the bone marrow and spleen in the low dose infused group (Fig 2B & 2C), and CD56 (NK cells) frequency was decreased in the low dose infused group compared with the high dose infused group (Fig 3B & 3C). The absolute CD3+ and CD56+ number, displayed as fold difference, were even more dramatically decreased in the femur (Fig 2D & 3D) and the spleen (Fig 2E & 3E) of low dose infused group.Because of the substantial difference in T cell subset frequencies between the two dosage groups in bone marrow and spleen, thymuses were collected and analyzed to study T cell development and maturation. Engraftment of hCD45+ cells in the thymuses were observed in 10 out of 15 animals (66.7%) in the low dose infused group and 12 out of 14 animals (85.7%) in the high dose infused group. Interestingly, in animals with high hCD45+ frequency, the total thymocyte CD3+ frequency was lower in the low dose infused group (Fig 4A). Additionally, the low dose infused group had lower CD3+CD4+ T cell frequency (Fig 4B) and higher CD3+CD4+CD8+ T cell frequency (Fig 4C), suggesting low dose infused group had a decreased mature T cell population and increased immature T cell population in the thymus.In contrast, the low dose hUCB CD34+ cells infused group had increased hCD19 (B cells) frequency in the peripheral blood, bone marrow and spleen (Fig 5A-5C), while the absolute hCD19 (B cells), displayed as fold difference, did not show a statistically significant difference between the two groups (Fig 5D & 5E).ConclusionsIn summary, our findings suggest that (1) transplanted hUCB cell dosage is inversely correlated with time to engraftment (2) low transplanted hUCB cell dosage resulted in skewed immune cell population which may contribute to delayed immune recovery after allogeneic HSCT. DisclosuresNo relevant conflicts of interest to declare.

Comparison of empirical likelihood and its dual likelihood under density ratio model

ABSTRACTDensity ratio models (DRMs) are commonly used semiparametric models to link related populations. Empirical likelihood (EL) under DRM has been demonstrated to be a flexible and useful platform for semiparametric inferences. Since DRM-based EL has the same maximum point and maximum likelihood as its dual form (dual EL), EL-based inferences under DRM are usually made through the latter. A natural question comes up: is there any efficiency loss of doing so? We make a careful comparison of the dual EL and DRM-based EL estimation methods from theory and numerical simulations. We find that their point estimators for any parameter are exactly the same, while they may have different performances in interval estimation. In terms of coverage accuracy, the two intervals are comparable for non- or moderate skewed populations, and the DRM-based EL interval can be much superior for severely skewed populations. A real data example is analysed for illustration purpose.

Estimating Desired Sample Size for Simple Random Sampling of a Skewed Population

ABSTRACTA simulation study was conducted to assess how well the necessary sample size to achieve a stipulated margin of error can be estimated prior to sampling. Our concern was particularly focused on performance when sampling from a very skewed distribution, which is a common feature of many biological, economic, and other populations. We examined two approaches for estimating sample size—one being the commonly used strategy aimed at regulating the average magnitude of the stipulated margin of error and the second being a previously proposed strategy to control the tolerance probability with which the stipulated margin of error is exceeded. Results of the simulation revealed that (1) skewness does not much affect the average estimated sample size but can greatly extend the range of estimated sample sizes; and (2) skewness does reduce the effectiveness of Kupper and Hafner's sample size estimator, yet its effectiveness is negatively impacted less by skewness directly, and to a much greater degree by the common practice of estimating the population variance via a pilot sampling from the skewed population. Nonetheless, the simulations suggest that estimating sample size to control the probability with which the desired margin of error is achieved is a worthwhile alternative to the usual sample size formula that controls the average width of the confidence interval only.

Truly selective primary IgM deficiency is probably very rare.

Isolated decreased serum-immunoglobulin (Ig)M has been associated with severe and/or recurrent infections, atopy and autoimmunity. However, the reported high prevalence of clinical problems in IgM-deficient patients may reflect the skewed tertiary centre population studied so far. Also, many papers on IgM deficiency have included patients with more abnormalities than simply IgM-deficiency. We studied truly selective primary IgM deficiency according to the diagnostic criteria of the European Society for Immunodeficiencies (ESID) (true sIgMdef) by reviewing the literature (261 patients with primary decreased serum-IgM in 46 papers) and analysing retrospectively all patients with decreased serum-IgM in a large teaching hospital in 's-Hertogenbosch, the Netherlands [1 July 2005-23 March 2016; n=8049 IgM <0·4 g/l; n=2064 solitary (IgG+IgA normal/IgM<age-matched reference)]. A total of 359 of 2064 (17%) cases from our cohort had primary isolated decreased serum-IgM, proven persistent in 45 of 359 (13%) cases; their medical charts were reviewed. Our main finding is that true sIgMdef is probably very rare. Only six of 261 (2%) literature cases and three of 45 (7%) cases from our cohort fulfilled the ESID criteria completely; 63 of 261 (24%) literature cases also had other immunological abnormalities and fulfilled the criteria for unclassified antibody deficiencies (unPAD) instead. The diagnosis was often uncertain (possible sIgMdef): data on IgG subclasses and/or vaccination responses were lacking in 192 of 261 (74%) literature cases and 42 of 45 (93%) cases from our cohort. Our results also illustrate the clinical challenge of determining the relevance of a serum sample with decreased IgM; a larger cohort of true sIgMdef patients is needed to explore fully its clinical consequences. The ESID online Registry would be a useful tool for this.

Stratification of Skewed Populations: A Comparison of Optimisation‐based versus Approximate Methods

SummarySurvey statisticians use either approximate or optimisation‐based methods to stratify finite populations. Examples of the former are the cumrootf (Dalenius &amp; Hodges, ) and geometric (Gunning &amp; Horgan, ) methods, while examples of the latter are Sethi () and Kozak () algorithms. The approximate procedures result in inflexible stratum boundaries; this lack of flexibility results in non‐optimal boundaries. On the other hand, optimisation‐based methods provide stratum boundaries that can simultaneously account for (i) a chosen allocation scheme, (ii) overall sample size or required reliability of the estimator of a studied parameter and (iii) presence or absence of a take‐all stratum. Given these additional conditions, optimisation‐based methods will result in optimal boundaries. The only disadvantage of these methods is their complexity. However, in the second decade of 21st century, this complexity does not actually pose a problem. We illustrate how these two groups of methods differ by comparing their efficiency for two artificial populations and a real population. Our final point is that statistical offices should prefer optimisation‐based over approximate stratification methods; such a decision will help them either save much public money or, if funds are already allocated to a survey, result in more precise estimates of national statistics.

Sexual segregation of spiny dogfish (Squalus acanthias) off the northeastern United States: Implications for a male-directed fishery

Female spiny dogfish experienced high fishing pressure on the US east coast during the 1990’s. This led to a skewed population sex-ratio of 7 males per female which later declined to 4:1 as the stock was rebuilt. The current fishery still targets mature females, resulting in artificially high abundances of male spiny dogfish. Members of the fishing industry have proposed the creation of a male-directed fishery to sustainably harvest more of the available yield. To explore the potential for such a fishery, we investigated environmental factors associated with the spatiotemporal distribution of male spiny dogfish and male-skewed sex ratios. We analyzed data from 454,721 spiny dogfish caught in 2063 trawl samples during the Northeast Fisheries Science Center (NEFSC) annual spring and autumn bottom trawl surveys from 2009 to 2014. Consistent with previous research, there was clear spatial and temporal sexual segregation within the population. Male spiny dogfish could be harvested with little female bycatch along the continental shelf from Chesapeake Bay to Long Island at depths of 70–80m and 300–330m, approximately 90–150km or 240–270km from shore during spring. High proportions of male spiny dogfish in the catch were found in the western Gulf of Maine and on Georges Bank in the fall at depths 80–250m. Using boosted regression trees, we identified depth as the best environmental predictor of high (>75%) proportions of males in the catch, followed by distance from shore and temperature, for spring and fall season respectively. A new male-directed fishery appears to be feasible, and if responsibly managed, could potentially help return sex-ratios to natural levels (2:1), reduce fishing pressure on the female portion of the stock, and benefit local fishing communities that have struggled with restricted fishing opportunities in recent years.

Diversity changes of microbial communities into hospital surface environments

Previous works have demonstrated considerable variability in hospital cleanliness in Japan, suggesting that contamination is driven by factors that are currently poorly controlled. We undertook 16S rRNA sequence analysis to study population structures of hospital environmental microbiomes to see which factor(s) impacted contamination. One hundred forty-four samples were collected from surfaces of three hospitals with distinct sizes ("A": >500 beds, "B": 100-500 beds, "C": <100 beds). Sample locations of two ward types (Surgical and Internal) included patient room bed table (multiple) (4BT), patient overbed table (multiple) (4OT), patient room sink (multiple) (4S), patient room bed table (single) (SBT), patient overbed table (single) (SOT), patient room sink (single) (SS), nurse desk (ND), and nurse wagon (NW). Total DNA was extracted from each sample, and the 50 samples that yielded sufficient DNA were used for further 16S rRNA sequencing of hospital microbiome populations with cluster analysis. The number of assigned bacterial OTU populations was significantly decreased in hospital "C" compared to the other hospitals. Cluster analysis of sampling locations revealed that the population structure in almost all locations of hospital "C" and some locations in the other hospitals was very similar and unusually skewed with a family, Enterobacteriaceae. Interestingly, locations included patient area (4OT, 4BT, SBT) and nurse area (ND), with a device (NW) bridging the two and a place (4S and SS) shared between patients or visitors. We demonstrated diversity changes of hospital environmental microbiomes with a skewed population, presumably by medical staff pushing NWs or sinks shared by patients or visitors.

New two-sample tests for skewed populations and their connection to theoretical power of Bootstrap-t test

Various tests are available to compare the means of two populations. Tests for skewed data, however, are not well studied even though they are often needed in pharmaceutical study and agricultural economics. In particular, there is no available result to give power and sample size calculation for a two-sample Bootstrap-t test in skewed populations. In this paper, we propose easy-to-compute new tests and study their theoretical properties. The proposed work starts with derivation of a second-order Edgeworth expansion for the pooled two-sample t-statistic. Then new test rejection regions are formed based on Cornish–Fisher expansion of quantiles. The new tests account for first-order and second-order population skewnesses that were ignored in two-sample t test. We report the theoretical type I error accuracy and power of the newly proposed tests and the large sample t test. We also provide the detailed conditions under which the proposed tests give better power than the two-sample large sample test. Our new tests, \(\hbox {TCF}_1\) and TCF, are asymptotically equivalent to Bootstrap-t test up to \(O(N^{-1})\) and \(O(N^{-3/2})\), respectively. Compared with commonly used two-sample parametric and nonparametric tests, the new tests are computationally efficient, give better power for skewed data with moderate sample size, and provide sample size calculation to achieve desired power at a given significance level. Empirical studies confirmed our theoretical results.

Medical overpayment estimation: A Bayesian approach

Overpayment estimation using a sample of audited medical claims is an often used method to determine recoupment amounts. The current practice based on central limit theorem may not be efficient for certain kinds of claims data, including skewed payment populations with partial overpayments. As an alternative, we propose a novel Bayesian inflated mixture model. We provide an analysis of the validity and efficiency of the model estimates for a number of payment populations and overpayment scenarios. In addition, learning about the parameters of the overpayment distribution with increasing sample size may provide insights for the medical investigators. We present a discussion of model selection and potential modelling extensions.

Immune Antibody Libraries: Manipulating The Diverse Immune Repertoire for Antibody Discovery.

Antibody phage display is highly dependent on the availability of antibody libraries. There are several forms of libraries depending mainly on the origin of the source materials. There are three major classes of libraries, mainly the naïve, immune and synthetic libraries. Immune antibody libraries are designed to isolate specific and high affinity antibodies against disease antigens. The pre-exposure of the host to an infection results in the production of a skewed population of antibodies against the particular infection. This characteristic takes advantage of the in vivo editing machinery to generate bias and specific immune repertoire. The skewed but diverse repertoire of immune libraries has been adapted successfully in the generation of antibodies against a wide range of diseases. We envisage immune antibody libraries to play a greater role in the discovery of antibodies for diseases in the near future.

Dobór modelu a obciążenie szacunku na przykładzie estymatora GREG w badaniu małych przedsiębiorstw

Estimation for a very skewed population containing extreme values is problematic, especially at a low level of aggregation. Traditional direct estimation methods do not provide satisfactory results. The growing demand for detailed information and the wider possibility of using data from administration registers has increased the importance of recognising more sophisticated estimation methods. Generalised Regression (GREG) estimation is an example of one such type. The paper examines the importance of the model chosen in GREG estimation in dealing with highly variable and outlier-prone populations. The model-assisted GREG estimator is applied to a real business survey. Lagged variables from administrative registers were used as the auxiliary variables. The variable of interest – mean revenue of small companies – was estimated for provinces cross-classified by categories of economic activity.

Effect of Oat Forthe Treatment of Hypertriglyceridemia; Randomized Controlled Trial

Introduction: In Mexico, the cardiovascular diseases constitute the first cause of death, from which 56% are from Coronary artery disease, having a very stretch relation with Dyslipidemia. Objective: To determine if the oat extract is effective, safe, and well tolerated for the treatment of hypertriglyceridemia. Material and methods: Randomized clinical trial, in volunteers with serum triglyceride levels of 200 mg/dL or more. Two treatments were distributed; 40 gr. of oat, compared to 40 gr. of flaxseed in the morning fasting in both groups, with a follow-up of four weeks with baseline measurements and final lipid profile with diet control and exercise. Analysis of the results: Student’s t-test, was used for the comparison of means, the Wilcoxon signed-rank test was used for skewed populations. Fisher's exact test was used to compare percentages. It was considered a statistical significance of p<0.05. Results: Thirty volunteers were studied, 15 for the oat group and 15 for the flaxseed group; two individuals from the oat group were eliminated due to the presence of minor adverse effects, leaving only 13 volunteers. No significant differences were found when comparing the oat group against the flaxseed group in the serum triglyceride levels (p=0.247 and 0.436 at the beginning and the end, respectively), no significant difference was found in the serum triglyceride levels in the oat group (initial 298.80 ± 114.60 against 307.20 ± 126.95 at the end, p=0.798), similar results were found in the flaxseed group (initial 351.61 ± 155.17 against 303.23 ± 117.40 at the end, p=0.152). I t was found that in both groups there was significant reduction in weight. Conclusions: the use of oats and flaxseeds were ineffective in lowering the serum triglyceride levels.

And R control charts based on weighted variance with left-right tail-weighted ratio for skewed distributions

ABSTRACTThe study proposed the average and range control charts by considering the generalized lambda distribution, the percentile-based method, and the weighted variance with left-right tail-weighted ratio for skewed populations. When the underlying distribution is Weibull, Burr, gamma, lognormal, or inverse Gaussian, the proposed control charts have Type I risks, which are closer to 0.27% of the normal distribution, and they do not rapidly vary with sample sizes and the shape of a distribution. Type II risks of the proposed control charts are closer to those of the exact charts than to those of the skewness correction and weighted variance charts.