Low Degree Of Correlation Research Articles

IMPACT OF CELEBRITY ENDORSEMENTS ON CONSUMERS’ PURCHASE INTENTION: A Study of Indian Consumers

The use of celebrity endorsements in advertising has become a trend and a perceived winning formula of corporate image building and product marketing. As existing media get increasingly cluttered, the need to stand out has become paramount and celebrities have proved to be the ideal way to ensure brand prominence. Research has shown that the use of celebrity endorsers brings many positive effects in terms of positive feelings towards the ad and the brand, a positive brand attitude and increased purchase intention for the brand. Numerous researches have proved empirically the effectiveness and the positive influence of celebrity endorsements in advertising, particularly on purchase intention. However, there is no common consensus on whether attractiveness, trustworthiness and expertise of the celebrity endorsers have a significant impact on consumers’ purchase intention. Through a survey of 336 Indian respondents who are exposed to celebrity endorsements for various products/brands, the present study attempts to find out the impact of celebrity endorsements on consumers’ purchase intention. The three-dimensional scale proposed by Roobina Ohanian (1990) has been used for the purpose. Thus, the present study considers three attributes of celebrity endorsements as suggested by Ohanian - attractiveness, trustworthiness and expertise. The study also attempts to find out the individual impact of these dimensions on consumers’ purchase intention. Exploratory factor analysis was used to reconfirm the factor structure. The model used was empirically tested for unidimensionality, reliability, convergent validity and discriminant validity, using confirmatory factor analysis. Structural equation modeling was used to find out the impact of celebrity endorsements on purchase intention. Results reveal that celebrity endorsements have a significant impact on consumers’ purchase intention. However, the beta coefficients reveal a low degree of correlation between celebrity endorsements and purchase intention. Further, attractiveness and trustworthiness are found to have a significant impact on the purchase intention, while expertise did not have a significant impact on purchase intention.

Is There a Role for Islamic Bonds in Global Diversification Strategies? An Empirical Analysis of Risk Transmissions and Dynamic Correlations

This paper explores international diversification benefits of Islamic bonds (sukuk) by examining dynamic spillovers and correlations between sukuk and conventional bond and stock markets. Asymmetric volatility spillover effects are observed from global debt and equity markets to Islamic bonds, suggesting that volatility on conventional markets has opposite spillover effects on Islamic bonds. The analysis of dynamic correlations suggests a low degree of association between these securities and global stock markets with episodes of negative correlations observed, particularly during market crisis periods. The low degree of correlation plays a significant role in the performance of these securities as diversifiers for global stock portfolios. We observe that Islamic bonds can provide valuable diversification benefits for conventional stock portfolios that are not possible to obtain from conventional bonds, underscoring the significance of Islamic bonds as a viable alternative to its conventional counterparts.

Evaluation of the Effusion within Biceps Long Head Tendon Sheath Using Ultrasonography.

BackgroundMany shoulder diseases are related to glenohumeral joint synovitis and effusion. The purpose of the present study is to detect effusion within the biceps long head tendon sheath as the sign of glenohumeral joint synovitis using ultrasonography, and to evaluate the clinical meaning of effusion within the biceps long head tendon sheath.MethodsA consecutive series of 569 patients who underwent ultrasonography for shoulder pain were reviewed retrospectively and ultimately, 303 patients were included. The authors evaluated the incidence and amount of the effusion within the biceps long head tendon sheath on the ultrasonographic short axis view. Furthermore, the authors evaluated the correlation between the amount of effusion within the biceps long head tendon sheath and the range of motion and the functional score.ResultsThe effusion within the biceps long head tendon sheath was detected in 58.42% of the patients studied: 69.23% in adhesive capsulitis, 56.69% in rotator cuff tear, 41.03% in calcific tendinitis, and 33.33% in biceps tendinitis. The average amount of the effusion within the biceps long head tendon sheath was 1.7 ± 1.6 mm, and it was measured to be the largest in adhesive capsulitis. The amount of effusion within biceps long head tendon sheath showed a moderate to high degree of correlation with the range of motion, and a low degree of correlation with the functional score and visual analogue scale for pain in each type of shoulder disease.ConclusionsThe effusion within the biceps long head tendon sheath is closely related to the range of motion and clinical scores in patients with painful shoulders. Ultrasonographic detection of the effusion within the biceps long head tendon sheath might be a simple and easy method to evaluate shoulder function.

SU-E-T-157: Evaluation and Comparison of Doses to Pelvic Lymph Nodes and to Point B with 3D Image Guided Treatment Planning for High Dose Brachytherapy for Treatment of Cervical Cancer

Purpose: To estimate and compare the doses received by the obturator, external and internal iliac lymph nodes and point Methods: CT-MR fused image sets of 15 patients obtained for each of 5 fractions of HDR brachytherapy using tandem and ring applicator, were used to generate treatment plans optimized to deliver a prescription dose to HRCTV-D90 and to minimize the doses to organs at risk (OARs). For each set of image, target volume (GTV, HRCTV) OARs (Bladder, Rectum, Sigmoid), and both left and right pelvic lymph nodes (obturator, external and internal iliac lymph nodes) were delineated. Dose-volume histograms (DVH) were generated for pelvic nodal groups (left and right obturator group, internal and external iliac chains) Per fraction DVH parameters used for dose comparison included dose to 100% volume (D100), and dose received by 2cc (D2cc), 1cc (D1cc) and 0.1 cc (D0.1cc) of nodal volume. Dose to point B was compared with each DVH parameter using 2 sided t-test. Pearson correlation were determined to examine relationship of point B dose with nodal DVH parameters. Results: FIGO clinical stage varied from 1B1 to IIIB. The median pretreatment tumor diameter measured on MRI was 4.5 cm (2.7– 6.4cm).The median dose to bilateral point Bmore » was 1.20 Gy ± 0.12 or 20% of the prescription dose. The correlation coefficients were all <0.60 for all nodal DVH parameters indicating low degree of correlation. Only 2 cc of obturator nodes was not significantly different from point B dose on t-test. Conclusion: Dose to point B does not adequately represent the dose to any specific pelvic nodal group. When using image guided 3D dose-volume optimized treatment nodal groups should be individually identified and delineated to obtain the doses received by pelvic nodes.« less

Relationship between column-density and surface mixing ratio: Statistical analysis of O3 and NO2 data from the July 2011 Maryland DISCOVER-AQ mission

To investigate the ability of column (or partial column) information to represent surface air quality, results of linear regression analyses between surface mixing ratio data and column abundances for O3 and NO2 are presented for the July 2011 Maryland deployment of the DISCOVER-AQ mission. Data collected by the P-3B aircraft, ground-based Pandora spectrometers, Aura/OMI satellite instrument, and simulations for July 2011 from the CMAQ air quality model during this deployment provide a large and varied data set, allowing this problem to be approached from multiple perspectives. O3 columns typically exhibited a statistically significant and high degree of correlation with surface data (R2 > 0.64) in the P-3B data set, a moderate degree of correlation (0.16 < R2 < 0.64) in the CMAQ data set, and a low degree of correlation (R2 < 0.16) in the Pandora and OMI data sets. NO2 columns typically exhibited a low to moderate degree of correlation with surface data in each data set. The results of linear regression analyses for O3 exhibited smaller errors relative to the observations than NO2 regressions. These results suggest that O3 partial column observations from future satellite instruments with sufficient sensitivity to the lower troposphere can be meaningful for surface air quality analysis.

Correlation between multiple modulation instability side lobes in dispersion oscillating fiber

We investigate numerically and experimentally the spectral correlation between multiple modulation instability (MI) side lobes in a dispersion oscillating fiber. By leveraging the dispersive Fourier transformation, we acquire instantaneous spectra and investigate the energy correlation between individual MI sidebands through scattergrams. We found that conjugate MI side lobes are strongly correlated while other combinations experience a very low degree of correlation, revealing that parametric processes related to each side lobe pair act quasi-independently.

Domain biased Bilingual Parallel Data Extraction and its Sentence Level Alignment for English-Hindi Pair

Creation of Parallel Corpora and efficient corporal alignment at sentential level for structurally distinct languages having relatively low degree of correlation remains a challenge. This work emphasizes the importance of domain biased parallel data collection and a structured methodology to obtain the same for English-Hindi language duet. Further, its sentential alignment has also been undertaken since the participating languages are structurally distinct. In essence two aspects of this study is collection of parallel corpora from different domains and aligning the extracted parallel corpus at sentence level. The proposition is intended to help researchers in the field of Natural Language Processing help contribute better in terms of accuracy, precision and robustness of their proposition. This being possible only with availability of abundant parallel corpora and more so only if the parallel corpora are available domain wise and aligned at least at sentence level. The language pair considered for the development of the algorithm is English-Hindi. The algorithm being generic in nature makes our proposition scalable to other like structured language pairs.

Missing Data Imputation Using a Regime Switching Technique

The purpose of this paper is to develop a regime switching technique to optimise mean and regression of a missing data set whose sample is small in size with a low degree of correlation. The data sets were first generated with a simple random method and later treated with the missing completely at random method (MCAR) in order to simulate complete data sets. We classified the data sets with different scenarios of sample size, degree of correlation and percentage of missing data. Moreover, we performed the tests with the missing data imputation techniques, namely: (i) mean imputation (MI), (ii) regression imputation (RI), (iii) regime switching for mean imputation (RsMI), (iv) regime switching for regression imputation (RsRI), (v) average regime switching between mean and regression imputation (aRsMRI), and (vi) weighted regime switching between mean and regression imputation (wRsMRI). The simulation results showed that in the scenario of small sample size and low degree correlation, wRsMRI techniques outperformed other techniques which use MSE evaluate accuracy.

Cardiotocography in the prognosis of perinatal outcome.

ABSTRACTAim:The objective of the study was to examine whether cardiotocography can (CTG) predict asphyxia of the embryo, manifested as hypoxic-ischemic encephalopathy (HIE), and to what extent one can rely on CTG record.Material and methods:Retrospective research was carried out at the Clinic for Gynecology and Obstetrics UKC Tuzla and medical documentation from the history of mothers and newborns was used. The study group consisted of 68 pregnancies and newborns who developed HIE. The control group consisted of 40 pregnancies, which resulted in birth of healthy newborns – without signs of asphyxia. CTG records were analyzed, Apgar score, the ways of finishing delivery.Results:Pathological CTG records (bradycardia 100, tachycardia 180, silent type of curve, late decelerations) were found in 45 (66,17%) cases of the study group in comparison to 11 (27,5%) in the control group. In the study group Apgar score in 5th minute lower than 7 had 17,46% newborns and the highest incidence of the normally finished deliveries. We conclude that cardiotocography is one of the reliable methods of fetal monitoring in pregnancy and delivery, and that pathological CTG record very likely indicates the possible presence of perinatal asphyxia.Conclusion:Achieving a low degree of correlation between pathological intrapartum cardiotocography findings and long-term outcome of children can be achieved by rapid and adequate obstetric intervention and the relatively short duration of fetal acidosis, and optimal procedures during intensive care of newborns.

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Introduction: Timely recognition of delirium in the intensive care unit (ICU) using validated tools such as The Confusion Assessment Method for the ICU (CAM-ICU) is essential to appropriate management. The purpose of this study was to describe the state of delirium assessment prior to the implementation of an ICU delirium algorithm. Methods: Patients 18-89 years old newly admitted to the surgical ICU with an expected ICU length of stay > 48 hours were eligible for evaluation. A pharmacist assessed patients daily using the CAM-ICU over a 2 week period. The pharmacist evaluation was compared to the nursing assessment for correlation. Nursing and physician assessments were also compared. The nursing CAM-ICU was considered inappropriate if: 1) CAM-ICU was documented while the patient had a RASS score of -4 or -5 or 2) CAM-ICU was charted as 'unable to assess' with a RASS score of -3 or greater. Additional risk factors for delirium were also collected. Descriptive statistics were used to summarize demographic variables and clinical outcomes. Results: A total 89 patient-days for the 20 patients were included. The median patient age was 50 years (range 23-89) and 60% of were male. No patients had hepatic encephalopathy, 3 were uremic, 1 experienced illicit drug withdrawal, and 3 experienced alcohol withdrawal. Only one patient had documented dementia prior to ICU admission. Pharmacy and nursing CAM-ICU assessments correlated in 59.6% of cases and physician and nursing correlation occurred in 60.6% of cases. The CAM-ICU was characterized as inappropriate for 46 of 178 nursing documented evaluations (25.9%). The most common error involved documentation as 'unable to assess' when the assessment should have occurred based on the documented level of sedation. There was only one occurrence where a CAM-ICU was inappropriately performed when the RASS score was -4 or -5. Conclusions: Assessment of ICU delirium is inconsistent in our surgical ICU. A low degree of correlation was seen between practitioners from different professions. Additionally, the CAM-ICU assessment was frequently documented as 'unable to assess' based on level of sedation. Future directions to improve assessment of ICU delirium within our surgical ICU include practitioner education and algorithm implementation.

Estudo das relações comunicativas no processo de gestão de uma instituição de saúde

OBJETIVO: relacionar as estratégias comunicativas adotadas na gestão de uma instituição de saúde com a percepção da comunicação pelos sujeitos participantes. MÉTODO: estudo descritivo-comparativo, com amostra por tipicidade, de recorte transversal. O estudo foi realizado em uma instituição de saúde do estado de Minas Gerais. Foram entrevistados 56 sujeitos de seis setores da instituição por meio de aplicação de questionário com 15 questões fechadas, que abordam desde a identificação do sujeito até as ações de planejamento, execução e avaliação da gestão e a percepção da comunicação e meios utilizados para se comunicar. Foi realizada análise descritiva e utilização do índice Kappa. RESULTADOS: os entrevistados, em sua maioria, relataram que as reuniões nas quais ocorre o planejamento não são exclusivas para tal atividade. Nelas sempre estão presentes as chefias diretas, ao contrário das indiretas. Quanto à execução das ações, observou-se que todos os membros da equipe se responsabilizam pelas atividades e compartilham informações durante o processo de trabalho. Foi relatado ainda que a avaliação ocorre de maneira assistemática e a presença das chefias direta e indireta é semelhante ao que ocorre na etapa de planejamento. Foi encontrado baixo grau de concordância entre as respostas. A percepção dos sujeitos sobre a comunicação foi considerada satisfatória, apontando que não é estabelecida relação direta entre a comunicação e o processo de trabalho. CONCLUSÃO: considera-se que os dados obtidos nesse estudo foram relevantes, de modo que permitiram discutir o papel da comunicação no sistema gestor pesquisado.

SFCscoreRF: A Random Forest-Based Scoring Function for Improved Affinity Prediction of Protein–Ligand Complexes

A major shortcoming of empirical scoring functions for protein-ligand complexes is the low degree of correlation between predicted and experimental binding affinities, as frequently observed not only for large and diverse data sets but also for SAR series of individual targets. Improvements can be envisaged by developing new descriptors, employing larger training sets of higher quality, and resorting to more sophisticated regression methods. Herein, we describe the use of SFCscore descriptors to develop an improved scoring function by means of a PDBbind training set of 1005 complexes in combination with random forest for regression. This provided SFCscore(RF) as a new scoring function with significantly improved performance on the PDBbind and CSAR-NRC HiQ benchmarks in comparison to previously developed SFCscore functions. A leave-cluster-out cross-validation and performance in the CSAR 2012 scoring exercise point out remaining limitations but also directions for further improvements of SFCscore(RF) and empirical scoring functions in general.

Comparison of optic area measurement using fundus photography and Optical Coherence Tomography between optic nerve head drusen and control subjects

To compare optic disc area measurement between optic nerve head drusen (ONHD) and control subjects using fundus photography, time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). We also made a comparison between each of the three techniques. We performed our study on 66 eyes (66 patients) with ONHD and 70 healthy control subjects (70 controls) with colour ocular fundus photography at 20º (Zeiss FF 450 IR plus), TD-OCT (Stratus OCT) with the Fast Optic Disc protocol and SD-OCT (Cirrus OCT) with the Optic Disc Cube 200 × 200 protocol for measurement of the optic disc area. The measurements were made by two observers and in each measurement a correction of the image magnification factor was performed. Measurement comparison using the Student's t-test/Mann-Whitney U test, the intraclass correlation coefficient, Pearson/Spearman rank correlation coefficient and the Bland-Altman plot was performed in the statistical analysis. Mean and standard deviation (SD) of the optic disc area in ONHD and in controls was 2.38 (0.54) mm(2) and 2.54 (0.42) mm(2), respectively with fundus photography; 2.01 (0.56) mm(2) and 1.66 (0.37) mm(2), respectively with TD-OCT, and 2.03 (0.49) mm(2) and 1.75 (0.38) mm(2), respectively with SD-OCT. In ONHD and controls, repeatability of optic disc area measurement was excellent with fundus photography and optical coherence tomography (TD-OCT and SD-OCT), but with a low degree of agreement between both techniques. Optic disc area measurement is smaller in ONHD compared to healthy subjects with fundus photography, unlike time-domain and spectral-domain optical coherence tomography in which the reverse is true. Both techniques offer good repeatability, but a low degree of correlation and agreement, which means that optic disc area measurement is not interchangeable or comparable between techniques.

Scanning laser edema index: A reliable tool to correlate with diabetic retinopathy and systemic risk factors?

To correlate Heidelberg Retina Tomograph (HRT) derived macular edema (DME) index with severity of diabetic retinopathy and systemic factors.A total of 300 diabetic patients were recruited for the study for each of them a value for the macular edema index was obtained using the HRT II. Patients' age, gender, duration and type of diabetes mellitus, latest HbA1c result and presence or absence of co-morbid factors (hypertension, ischemic heart disease, nephropathy) were recorded together with the stage of diabetic retinopathy. These were correlated with DME.Out of 300 patients, HRT defined macula edema was seen in 68 patients (22.6%). There is a wider and higher range (95% percentile) of macula edema index in the severe non proliferative diabetic retinopathy (NPDR) group. Independent samples t test showed significant difference between the severe NPDR group and no DR group (p<0.001), mild NPDR group (p<0.05) and moderate NPDR group (p<0.05). A higher macula edema index was also found to have a low degree of correlation with more advanced stages of retinopathy (r=0.310; p<0.001). Also nephropathy showed a strong and significant correlation with DME. Hypertension had moderately significant correlation with DME. This study found no correlation between ischemic heart disease and DME.HRT derived scanning laser edema index is a reliable objective tool to evaluate diabetic retinopathy and systemic risk factors.

Radiographic features, better than clinical features, represent actual joint degeneration and inflammation: considerations for total knee replacement surgery

Radiographic features, better than clinical features, represent actual joint degeneration and inflammation: considerations for total knee replacement surgery

The organic and mineral matter contents in deposits infilling floodplain basins: Holocene alluviation record from the Kłodnica and Osobłoga river valleys, southern Poland

The work examines the timing and environmental conditions of floodplain sedimentation in the valleys of the upland Kłodnica and piedmont Osobłoga rivers in the Upper Odra River basin. A distribution of 52 14C-ages shows relatively high floodplain sedimentation at the Late Glacial–Holocene transition, more stable floodplain environments since the Early (in the Kłodnica Valley) and Middle Holocene (in the Osobłoga Valley) and a gradual increase in floodplain deposition in the Late Holocene (since <3.4kyr BP). Organic matter [OM] and mineral matter [MM] fluctuations were correlated with variables responsible for the activation of erosion (i.e. vegetation changes, human impact and hydrological events) as well as factors affecting the local record of sedimentation (i.e. valley morphology, hydrologic conditions and episodes of local erosion). A clear relationship is shown between an increase in alluviation and climate- or human-induced extension of unforested areas. The deposition of mineral-rich sediments increases rapidly during periods characterized by non-arboreal pollen values exceeding approximately 8% in pollen diagrams. On the other hand, the results obtained do not confirm significant interactions between Holocene changes in forest composition and alluviation. Despite the settlement of agrarian groups, the sedimentary record of human activity in the Osobłoga catchment is very poor during the Neolithic and early Bronze Age. A large-scale alluviation of the Osobłoga and Kłodnica valleys was initiated during the settlement of people of the Lusatian culture from the middle Bronze Age and escalated in the early Middle Ages and Modern Times. The deposition of products of soil erosion was limited to between ca. 1.9–1.2kyrBP, probably due to demographic regression during the Migration Period. Comparison of OM/MM fluctuations with phases of increased fluvial activity does not show a relationship between Holocene wetter phases and catchment sediment yield. Sedimentary episodes in the Upper Odra basin also show a low degree of correlation with the probability density curve of the 14C-ages. The results obtained in the Kłodnica and Osobłoga valleys indicate a strong to moderate correlation between the spatial distribution of the study sites and the origin of MM-rich deposits, but a weak correlation between the spatial distribution of the study sites and TOC content. Such a pattern suggests that OM/MM fluctuations relate predominantly to the changes in sediment yield, although morphological conditions have a significant impact on the capture potential of sedimentary basins during phases of alluviation. Additionally, high OM content is not a simple function of an increase in wetness of the sedimentary environment. On the other hand, hydrologically-conditioned hiatuses as well as erosion episodes impoverish the sedimentary record, complicating the consideration on the geochronology of deposits and making it difficult to calculate reliable accumulation rates. However, they do not reduce the value of OM/MM fluctuations as an indicator of alluviation events for a preserved series of sediments.

The relationship between team identification and service quality perceptions in professional football

In this study the relationship between team identification and service quality perceptions of football spectators is examined. 608 football spectators from 3 different teams who played their games at the same stadium participated in the study. Spectators completed a questionnaire packet containing a demographic form, the Sport Spectator Identification Scale (SSIS) and Scale of Perceived Service Quality in Professional Sport (S_PSQPS). Examining correlation between service quality perceptions and team identification it was interesting to see that there was negatively inclined low degree of correlation between team identification and quality perceptions on physical environment. The difference determined in physical environment quality between the spectators of the 3 different teams playing their games at the same stadium is extremely striking. Core service quality perceptions presented a downward trend amongst spectators attending games for long periods of time and this stands out as a significant finding demanding the attention of professional football managers. Key words: Service, quality, identification, sport, football, spectators.

Abstract P1-11-11: Correlation between ER/PgR/Her-2/Ki67 Expression and Response to Neoadjuvant Endocrine Therapy for HR Positive Post-Menopausal Breast Cancer

Abstract Background: Endocrine therapy was standard adjuvant treatment for hormone receptor positive breast cancer. However, there were factors other than receptor status could influence endocrine responsiveness. Neoadjuvant therapy was an excellent platform for predictive factors research, but the standard for evaluating the efficacy of neoadjuvant endocrine therapy was controversy. The aim of this study was to investigate the correlation among the results of different response evaluation system, and the relationships between ER/PgR/Her-2/Ki67 expression and the responses to neoadjuvant endocrine therapy for postmenopausal breast cancer. Methods: Data of consecutive 133 core needle biopsy (CNB) confirmed hormone receptor strongly positive (more than 50% tumor cell stained ER or PgR) postmenopausal breast cancer treated with neoadjuvant endocrine therapy were analysis retrospectively. All pts. were planned to receive endocrine therapy alone as their adjuvant treatment and prescribed Anastrozole 1 mg per day for 16 weeks before surgery. Clinical response were evaluated by using documented ultrasound records,pathological response was evaluated by one senior pathologist with Miller &amp; Payne classification. Cell cycle complete response was defined as post-treatment Ki67 ≥1%. The new slides of pre-treatment and surgical specimens were made for ER/PgR (ER\PR DakoCytomation)/Her-2 (Her-2 Dako HercepTest TM)/Ki67 (Ki67 Ventana) immunohistochemical staining through Benchmark XT Staining Instrument (Ventana Medical Systems. Inc. Arizona. USA) and classified by using image analysis system Ariol (Applied Imaging Inc., San-Jose, California, USA). Results: Clinical response were CR:0.8% PR:33.1% SD:66.1%, pathological response were G5:3% G4+G3:47.4% G2+G1:49.6%, Ki67 change were &amp;lt;1%: 22.8% decrease but &amp;gt;1%:45.1% no decrease: 32.1%. The correlation and consistency among the response evaluated differently were poor [table 1]. The per-treatment ER/PR/Her-2/Ki67 showed low degree of correlation with responses [table 2]. Pre-treatment ER≥90% and PR≥90% and Her-2 coudln't predict better response. The correlation and consistency among response evaluated in different system Conclusion: The correlation and consistency among the results of response to neoadjuvant endocrine therapy evaluated by different system were poor. ER/PgR/Her-2/Ki67 showed low degree of correlation to responses. It's difficult to predict response to Arimidex neoadjuvant endocrine therapy by using ER/PgR/Her-2/Ki67 expression. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-11-11.

A Microscopic Formulation for the Actin-Driven Motion of Listeria in Curved Paths

Using a generalized Brownian ratchet model that accounts for the interactions of actin filaments with the surface of Listeria mediated by proteins like ActA and Arp2/3, we have developed a microscopic model for the movement of Listeria. Specifically, we show that a net torque can be generated within the comet tail, causing the bacteria to spin about its long axis, which in conjunction with spatially varying polymerization at the surface leads to motions of bacteria in curved paths that include circles, sinusoidal-like curves, translating figure eights, and serpentine shapes, as observed in recent experiments. A key ingredient in our formulation is the coupling between the motion of Listeria and the force-dependent rate of filament growth. For this reason, a numerical scheme was developed to determine the kinematic parameters of motion and stress distribution among filaments in a self-consistent manner. We find that a 5–15% variation in polymerization rates can lead to radii of curvatures of the order of 4–20 μm, measured in experiments. In a similar way, our results also show that most of the observed trajectories can be produced by a very low degree of correlation, <10%, among filament orientations. Since small fluctuations in polymerization rate, as well as filament orientation, can easily be induced by various factors, our findings here provide a reasonable explanation for why Listeria can travel along totally different paths under seemingly identical experimental conditions. Besides trajectories, stress distributions corresponding to different polymerization profiles are also presented. We have found that although some actin filaments generate propelling forces that push the bacteria forward, others can exert forces opposing the movement of Listeria, consistent with recent experimental observations.

Evaluation of the protection induced by avian influenza vaccines containing a 1994 Mexican H5N2 LPAI seed strain against a 2008 Egyptian H5N1 HPAI virus belonging to clade 2.2.1 by means of serological and in vivo tests

Since 2006 Egypt has been facing an extensive epidemic of H5N1 highly pathogenic avian influenza (HPAI) with a huge number of outbreaks both in rural and intensively reared poultry areas. The use of efficacious vaccines in this country has been, and still remains, essential for the control and possible eradication of HPAI. The present study was performed to establish whether the administration of inactivated vaccines containing an H5 virus belonging to a different lineage to the Eurasian H5N1 HPAI viruses guarantees protection from clinical signs, provides significant immune response and is able to achieve a reduction of viral shedding in the face of a challenge with a contemporary H5N1 virus isolated in Egypt. Despite the genetic and antigenic differences between the vaccine strain (H5N2/Mexico) and the challenge strain (H5N1/Egypt), confirmed by molecular and serological (haemagglutination inhibition) tests, it was established that the immune response induced by these conventional vaccines is sufficient to prevent infection in the majority of birds challenged with a contemporary H5N1 Egyptian strain. The data reported in this study also indicate that there may be a low degree of correlation between haemagglutination inhibition titres, clinical protection and reduction of shedding.