Compression of Probabilistic XML documents

Probabilistic XML (PXML) files resulting from data integration can become extremely large, which is undesired. For XML there are several techniques available to compress the document and since probabilistic XML is in fact (a special form of) XML, it might benefit from these methods even more. In this research we search for compression mechanisms that are available for XML and implement one of them to customize it with respect to the properties of probabilistic XML. Experiments show that there is no significant improvement for combinations of traditional mechanisms with techniques that are specially designed for probabilistic XML

Matching Profiles from Social Network Sites

In recent years social networking sites have become very popular. Many people are member of one or more of these profile sites and tend to put a lot of informa- tion about themselves online. This often publicly available data can be useful for many purposes. Retrieving all available data from one person and merging it into one profile even more. Detection of which profiles belong to the same person becomes very important. This task is called Entity Resolution (ER).\ud In this research we develop a model to solve the ER problem for profiles from social networking sites. First we present a simple model. Then we try to improve this model by making use of the social networks a member can have on these sites. We believe that involving the networks can improve the results significantly.\ud General idea is that we have two sites with profiles. With the model we try to find out which profiles of the first profile site correspond to which profiles of the second profile site, whereby we assume a person to have at most one profile at each profile site.\ud In the simple model, we compare all profiles of the first profile site against all profiles of the second site. This comparison will result in a score for each pair: the pairwise similarity score. The higher this score, the higher the probability that these profiles belong to the same person. The pairs that satisfy the so-called pairwise threshold are the candidate matches. From these candidate matches, the matches are chosen.\ud In the network model, we start the same way. When the list of candidate matches is determined, the network phase is started. For each candidate match the network similarity score is calculated. This is done by determining the overlap in the networks of both profiles in the candidate match. The more overlap between the networks, the higher the network similarity score, the higher the probability that the profiles in the candidate match belong to the same person. This time, the candidate matches should satisfy a network threshold in order to stay a candidate match. Then from the remaining candidate matches, the matches are chosen.\ud In order to test whether the network model would indeed improve the simple model, we have set up experiments. Since no suitable data sets were available, we retrieved our own data set. Unfortunately, it appeared to have some limitations. Also, we have built a prototype that implemented the model. The prototype has several parameters for which we could vary the values in the experiments to find a good configuration.\ud The network model ensures that there are more conditions that need to be met to be a match. The experimental results confirm this. That means that the precision of the results increases. On the other side, due to these strict conditions, corresponding profiles are missed, which is undesired. However, in case there are ambiguous profiles in the set, the network model can distinguish the correct profile, which is highly desired. This situation will occur frequently in real life, hence we think the network model can really contribute to solving the ER problem

Seasonal Variation in Vitamin D3 Levels Is Paralleled by Changes in the Peripheral Blood Human T Cell Compartment

It is well-recognized that vitamin D3 has immune-modulatory properties and that the variation in ultraviolet (UV) exposure affects vitamin D3 status. Here, we investigated if and to what extent seasonality of vitamin D3 levels are associated with changes in T cell numbers and phenotypes. Every three months during the course of the entire year, human PBMC and whole blood from 15 healthy subjects were sampled and analyzed using flow cytometry. We observed that elevated serum 25(OH)D3 and 1,25(OH)2D3 levels in summer were associated with a higher number of peripheral CD4+ and CD8+ T cells. In addition, an increase in naïve CD4+CD45RA+ T cells with a reciprocal drop in memory CD4+CD45RO+ T cells was observed. The increase in CD4+CD45RA+ T cell count was a result of heightened proliferative capacity rather than recent thymic emigration of T cells. The percentage of Treg dropped in summer, but not the absolute Treg numbers. Notably, in the Treg population, the levels of forkhead box protein 3 (Foxp3) expression were increased in summer. Skin, gut and lymphoid tissue homing potential was increased during summer as well, exemplified by increased CCR4, CCR6, CLA, CCR9 and CCR7 levels. Also, in summer, CD4+ and CD8+ T cells revealed a reduced capacity to produce pro-inflammatory cytokines. In conclusion, seasonal variation in vitamin D3 status in vivo throughout the year is associated with changes in the human peripheral T cell compartment and may as such explain some of the seasonal variation in immune status which has been observed previously. Given that the current observations are limited to healthy adult males, larger population-based studies would be useful to validate these findings

Accuracy of abdominal organ motion estimation in radiotherapy using the right hemidiaphragm top as a surrogate during prolonged breath-holds quantified with MRI

Background: Respiratory motion presents a challenge in radiotherapy of thoracic and upper abdominal tumors. Techniques to account for respiratory motion include tracking. Using magnetic resonance imaging (MRI) guided radiotherapy systems, tumors can be tracked continuously. Using conventional linear accelerators, tracking of lung tumors is possible by determining tumor motion on kilo voltage (kV) imaging. But tracking of abdominal tumors with kV imaging is hampered by limited contrast. Therefore, surrogates for the tumor are used. One of the possible surrogates is the diaphragm. However, there is no universal method for establishing the error when using a surrogate and there are particular challenges in establishing such errors during free breathing (FB). Prolonged breath-holding might address these challenges. Purpose: The aim of this study was to quantify the error when using the right hemidiaphragm top (RHT) as surrogate for abdominal organ motion during prolonged breath-holds (PBH) for possible application in radiation treatments. Methods: Fifteen healthy volunteers were trained to perform PBHs in two subsequent MRI sessions (PBH-MRI1 and PBH-MRI2). From each MRI acquisition, we selected seven images (dynamics) to determine organ displacement during PBH by using deformable image registration (DIR). On the first dynamic, the RHT, right and left hemidiaphragm, liver, spleen and right and left kidney were segmented. We used the deformation vector fields (DVF), generated by DIR, to determine the displacement of each organ between two dynamics in inferior-superior (IS), anterior-posterior (AP), left-right (LR) direction and we calculated the 3D vector magnitude (|d|). The displacements of the RHT, both hemidiaphragms and the abdominal organs were compared using a linear fit to determine the correlation (R2 of the fit) and the displacement ratio (DR, slope of the fit) between displacements of the RHT and each organ. We quantified the median difference between the DRs of PBH-MRI1 and PBH-MRI2 for each organ. Additionally, we estimated organ displacement in the second PBH by applying the DR from the first PBH to the displacement of the RHT measured during the second PBH. We compared the estimated organ displacement to the measured organ displacement during the second PBH. The difference between the two values was defined as the estimation error of using the RHT as a surrogate and assuming a constant DR over MRI sessions. Results: The linear relationships were confirmed by the high R2 values of the linear fit between the displacements of the RHT and the abdominal organs (R2 > 0.96) in the IS and AP direction and |d|, and high to moderate correlations in the LR direction (0.93 > R2 > 0.64). The median DR difference between PBH-MRI1 and PBH-MRI2 varied between 0.13 and 0.31 for all organs. The median estimation error of the RHT as a surrogate varied between 0.4 and 0.8 mm/min for all organs. Conclusion: The RHT could serve as an accurate surrogate for abdominal organ motion during radiation treatments, for example, in tracking, provided the error of the RHT as motion surrogate is taken into account in the margins. Trial registration: The study was registered in the Netherlands Trial Register (NL7603)

1,25-dihydroxyvitamin D3 Modulates Cytokine Production Induced by Candida albicans: Impact of Seasonal Variation of Immune Responses

Background. Our interest in immunological effects produced by vitamin D3 (1,25(OH)2D3) and its therapeutic potential prompted us to examine the role of 1,25(OH)2D3 on cytokine production by Candida albicans