436 research outputs found
Satisfaction and Interpersonal Closeness as Determinants of Relationship Commitment in Business-to-Business Relationships
The theory of embedded markets states that economic transactions are embedded in social relationships, and economic actors are influenced by both marketing variables and relationship properties. That is, within an exchange relationship actors derive utility from the attributes of a focal product and from interpersonal relationships. We investigate the different roles of satisfaction with a focal product and closeness between boundary personnel in a business-to-business relationship. We demonstrate that these constructs are distinct and differ with respect to antecedents and consequences in a larger nomological network with relationship commitment as the focal dependent variable. --Satisfaction,Closeness,Embeddedness
Integrating latent variables in discrete choice models â How higher-order values and attitudes determine consumer choice
Integrated choice and latent variable (ICLV) models represent a promising new class of models which merge classic choice models with the structural equation approach (SEM) for latent variables. Despite their conceptual appeal, to date applications of ICLV models in marketing are still rare. The present study on travel mode choice clearly demonstrates the value of ICLV models to enhance understanding of choice processes. In addition to the usually studied directly observable variables such as travel time, we show how abstract motivations such as power and hedonisms as well as attitudes such as a desire for flexibility impact on travel mode choice. Further, we can show that it is possible to estimate ICLV models with the widely available structural equation modeling package Mplus. This finding is likely to encourage wider usage of this appealing model class in the marketing field.Hybrid choice models; Mode choice; Values; Value-attitude hierarchy; Mplus
Finite-Frequency SKS Splitting: Measurement and Sensitivity Kernels
Splitting of SKS waves caused by anisotropy may be analyzed by measuring the splitting intensity, i.e., the amplitude of the transverse signal relative to the radial signal in the SKS time window. This quantity is simply related to structural parameters. Extending the widely used cross-correlation method for measuring travel-time anomalies to anisotropic problems, we propose to measure the SKS-splitting intensity by a robust cross-correlation method that can be automated to build large high-quality datasets. For weak anisotropy, the SKS-splitting intensity is retrieved by cross-correlating the radial signal with the sum of the radial and transverse signals. The cross-correlation method is validated based upon a set of Californian seismograms. We investigate the sensitivity of the SKS-splitting intensity to general anisotropy in the mantle based upon a numerical technique (the adjoint spectral-element method) considering the full physics of wave propagation. The computations reveal a sensitivity remarkably focused on a small number of elastic parameters and on a small region of the upper mantle. These fundamental properties and the practical advantages of the measurement make the cross-correlation SKS-splitting intensity particularly well adapted for finite-frequency imaging of upper-mantle anisotropy
Axillary web syndrome after treatment for breast cancer: An exploration of imaging evidence of fascial changes and its relationship to clinical variables
Breast cancer is the most commonly diagnosed cancer in women and surgery remains the primary treatment. Evaluation of tumour spread is done by axillary lymph node assessment by surgical excision. Such invasive treatments, in conjunction with adjuvant therapies such as chemotherapy, radiotherapy and hormonal therapy, may alter patient healing patterns giving rise to complications such as axillary web syndrome (AWS). AWS presents as a puckering web of axillary skin overlying a cord of tissue that tightens with shoulder abduction. It is painful, limits shoulder range of movement (ROM) and reduces the quality of life of the patients. The syndrome is elusive, does not occur in everyone and is thought to be self-limiting in nature with spontaneous cord resolution. Evidence, however, is pointing towards long-term morbidity in some patients. The cord itself has been hypothesised to be lymphatic or vascular in origin and damage during axillary surgery gives rise to the structure. Anatomically, the vascular structures are bound by the connective tissue network of fascia. The adhesive and puckering appearance of the cord on clinical examination and in limited biopsy studies could imply a possible role of damaged fascia in the syndrome. The fascia, as a three-dimensional body-wide network, has been shown to be a functional unit with the musculoskeletal system and is important in coordinating movement. Furthermore, the fascia contains numerous receptors imperative for proprioceptive and nociceptive functioning. The fibroblast cells and fibres that it comprises are involved in tissue healing and scar tissue formation. Chronic inflammation upon fascial damage can lead to tissue adhesions and fibrosis, rendering a non-functional scar. Ultrasonography (US) has been able to visualise fascial differences and has been used to examine fascial abnormalities including scars and adhesions. Physiotherapy treatment has been shown to aid in remobilising scar tissue and in being able to help improve morbidity in AWS patients. The authors therefore hypothesised that damaged fascia contributes to the symptomology of AWS. The present study set out to evaluate whether altered fascia plays a role in the syndrome using fascial explanations for risk factors in the AWS literature and US in patients with AWS to observe anatomical changes. Furthermore, the authors hypothesised that myofascial physiotherapy could aid in cord resolution and symptom improvement and that it would reflect in fascial changes on US. The current descriptive, observational, pilot, proof-of-concept case-series study focused on fascial changes before and after myofascial release physiotherapy in women presenting with AWS following breast cancer treatment (n = 11). At the time points, US in the area of interest (the axilla) and MRI scans of a single patient were done pre-physiotherapy. Furthermore, patient variables of ROM, pain and disability using the SPADI questionnaire, and quality of life using the FACT-B questionnaire, were evaluated to relate to any fascial differences between affected and unaffected arms on US and compared to findings after physiotherapy to determine trends. To observe fascial continuity, alignment of US scans was attempted. The results from the case studies and overall trends indicated thickened fascia, reduced continuity, decreased gliding potential and increased adherence between the different fascial layers on US in the majority of patients on the affected arm in the area of interest suggesting that they are changes resulting from the treatment. The findings related to the external cord appearance. On MRI, a fibrous band of tissue was observed connecting to muscles and skin. The findings were found to descriptively show a trend with reduced ROM and increased SPADI scores. No descriptive relationship with FACT-B was noted. Several patients (n = 6) continued with physiotherapy for six treatments. The treatment proved beneficial for all patients, who improved on ROM and SPADI scores. However, not all their symptoms were completely resolved. The findings corroborate observations on US showing improved gliding, more regular and organised fascia, and less adhesions post-physiotherapy. Cord resolution or reduction occurred in half of the patients. Risk factors for AWS as identified in the literature and related to the patients, such as more invasive treatments and (neo)adjuvant therapies, were explained to cause more fibrosis and possibly contributed to the symptoms seen but could not be verified in the study due to the small, varied sample. Furthermore, due to the difficulty of finding suitable patients and the low sample size, the current study could not statistically corroborate many correlations and hence was limited to descriptive trend description. Using the fascial literature, restricted fascia and adhesions could be explained to lead to biomechanical limitations, explaining reduced ROM and nociceptor activation as seen in pain reported in the study. A fibrosed vessel damaged during axillary surgery as well as surrounding fascial changes, which occurred as the result of the healing response, could explain the varying appearances of the cord. The author concluded that the trends seen suggest a link for morbidity resulting from fascial damage and adds weight to the evidence of fascial involvement in AWS. Wider fascial involvement on US and MRI descriptively related to the presence of cording, limited shoulder ROM and pain before and improvements and changes in the domains after physiotherapy, supported the hypotheses. The present study highlighted that myofascial release can be beneficial for patients suffering from AWS and suggests that US may be a feasible outcome measure to aid in evaluating fascia and fibrosis subsequent to physiotherapy, guide it and determine its efficacy. Furthermore, risk factors need to be identified to implement an early warning system for the sequelae of breast cancer so that patients at risk are identified timeously and receive the help they need to minimise the effect of the syndrome on their wellbeing in order to improve their quality of life
Inner core structure behind the PKP core phase triplication
The structure of the Earth's inner core is not well known between depths of âŒ100â200 km beneath the inner core boundary. This is a result of the PKP core phase triplication and the existence of strong precursors to PKP phases, which hinder the measurement of inner core compressional PKIKP waves at epicentral distances between roughly 143 and 148°. Consequently, interpretation of the detailed structure of deeper regions also remains difficult. To overcome these issues we stack seismograms in slowness and time, separating the PKP and PKIKP phases which arrive simultaneously but with different slowness. We apply this method to study the inner core's Western hemisphere beneath South and Central America using paths travelling in the quasi-polar direction between 140 and 150° epicentral distance, which enables us to measure PKiKPâPKIKP differential traveltimes up to greater epicentral distance than has previously been done. The resulting PKiKPâPKIKP differential traveltime residuals increase with epicentral distance, which indicates a marked increase in seismic velocity for polar paths at depths greater than 100 km compared to reference model AK135. Assuming a homogeneous outer core, these findings can be explained by either (i) inner core heterogeneity due to an increase in isotropic velocity or (ii) increase in anisotropy over the studied depth range. Although this study only samples a small region of the inner core and the current data cannot distinguish between the two alternatives, we prefer the latter interpretation in the light of previous work
Novel long non-coding RNAs of relevance for ulcerative colitis pathogenesis
Background and aims: The study aimed to identify yet unknown and uncharacterized long non-coding RNAs
(lncRNAs) in treatment-naĂŻve ulcerative colitis (UC), and to define their possible roles in UC pathogenesis. For
that purpose, accurate quantification methods for lncRNA transcript detection, multiple and âstringentâ strategies were applied. New insights in the regulation of functional genes and pathways of relevance for UC through
expression of lncRNAs are expected.
Methods: The study was based on sequencing data derived from a data set consisting of treatment-naĂŻve UC
patients (n = 14) and control subjects (n = 16). Two complementary aligners were used to identify lncRNAs.
Several different steps were used to validate differential expression including plotting the reads over the
annotation for manual inspection. To help determine potential lncRNA involvement in biological processes,
KEGG pathway enrichment was done on protein-coding genes which co-expressed with the lncRNAs.
Results: A total of 99 lncRNAs were identified in UC. The lncRNAs which were not previously characterized (n =
15) in UC or other autoimmune diseases were selected for down-stream analysis. In total, 602 protein-coding
genes correlated with the uncharacterized lncRNAs. KEGG pathway enrichment analysis revealed involvement
of lncRNAs in two significantly enriched pathways, lipid and atherosclerosis, and T-cell receptor signaling.
Conclusion: This study identified a set of 15 yet uncharacterized lncRNAs which may be of importance for UC
pathogenesis. These lncRNAs may serve as potential diagnostic biomarkers and might be of use for the development of UC treatment strategies in the future
Novel long-coding RNAs of relevance for ulcerative colitis pathogenesis
Poster presented at the Norwegian Bioinformatics Days 2022, Sundvolden, 28-30 September 2022.Introduction - LncRNAs have become a growing field of research. They are involved in diverse biological processes including expression regulation, and chromatin modification. Many lncRNAs have been characterized as involved in the occurrence and development of various human diseases, including cancer. A growing body of evidence implies a role for lncRNAs in UC by modulating the intestinal barrier, regulating the expression of inflammatory cytokines, and
polarization of macrophages.
Problems - Accurate quantification of lncRNA transcripts is challenging due to the low expression of lncRNAs, and their exons overlap protein-coding exons on the same strand.
Aims - The study aimed to define the role of uncharacterized long noncoding RNAs (lncRNAs) in treatment-naĂŻve ulcerative colitis (UC).
Method - To overcome difficulties in lncRNA transcript quantification, multiple and âstringentâ strategies were applied. New insights in the regulation of functional genes and pathways of relevance for UC through expression of lncRNAs are expected
Conclusion - This study identified a set of 15 yet uncharacterized lncRNAs which may be of importance for UC pathogenesis. These lncRNAs may serve as potential diagnostic biomarkers and might be of use for the development of UC treatment strategies in the future. The proposed method can also be helpful to quantify low expressed lncRNA transcripts in other datasets
The crustal structure from teleseismic P-wave coda-I.
S U M M A R Y The crustal structure beneath a seismic station has a large influence on the P-wave coda recorded by that station. In this study we employ the vertical and radial component of the crustal receiver response to determine the most important features of the crustal velocity structure beneath stations of the NARS array. The receiver response is estimated from the P-wave coda of teleseismic events by deconvolution with a source wavelet and by stacking responses of different events. The crustal velocity structure at the station is derived from these data by non-linear waveform inversion. The responses of some of the NARS stations show anomalous features such as an 'apparent delay' of the first arrival on the radial component relative to the onset on the vertical component. This appears to be a combined effect of very low velocities in the top layer of the model and a strong velocity discontinuity in the uppermost part of the crust. A high amplitude coda on the radial component is observed for stations on a structure with strong S-velocity gradients in the upper crust. The receiver responses of the NARS stations are generally well modelled by the synthetics of the final models of the inversions. The method provides an adequate procedure to estimate the dominant effects of the crustal structure at the site with the models representing the most significant velocity gradients of the crustal structure
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