Narrow absorption features in the co-added XMM-Newton RGS spectra of isolated Neutron Stars

We co-added the available XMM-Newton RGS spectra for each of the isolated X-ray pulsars RX\,J0720.4$-$3125, RX\,J1308.6+2127 (RBS\,1223), RX\,J1605.3+3249 and RX\,J1856.4$-$3754 (four members of the "Magnificent Seven") and the "Three Musketeers" Geminga, PSR\,B0656+14 and PSR\,B1055-52. We confirm the detection of a narrow absorption feature at 0.57 keV in the co-added RGS spectra of RX\,J0720.4$-$3125 and RX\,J1605.3+3249 (including most recent observations). In addition we found similar absorption features in the spectra of RX\,J1308.6+2127 (at 0.53 keV) and maybe PSR\,B1055-52 (at 0.56 keV). The absorption feature in the spectra of RX\,J1308.6+2127 is broader than the feature e.g. in RX\,J0720.4$-$3125. The narrow absorption features are detected with 2$\sigma$ to 5.6$\sigma$ significance. Although very bright and frequently observed, there are no absorption features visible in the spectra of RX\,J1856.4$-$3754 and PSR\,B0656+14, while the co-added XMM-Newton RGS spectrum of Geminga has not enough counts to detect such a feature. We discuss a possible origin of these absorption features as lines caused by the presence of highly ionised oxygen (in particular OVII and/or OVI at 0.57 keV) in the interstellar medium and absorption in the neutron star atmosphere, namely the absorption features at 0.57 keV as gravitational redshifted ($g_{r}$=1.17) OVIII.Comment: 14 pages, 10 figures and 10 tables. Accepted for publication by MNRAS (Sep 12th, 2011

The continued spectral evolution of the neutron star RX J0720.4-3125

We observed the isolated neutron star RX J720.4-3125 with Chandra's Low Energy Transmission Grating Spectrometer, following the XMM-Newton discovery of long term spectral evolution of this source. The new observation shows that the spectrum of RX J720.4-3125 has continued to change in the course of 5 months. It has remained hard, similar to the last XMM-Newton observation, but the strong depression observed with XMM-Newton at long wavelengths has disappeared. Contrary to the XMM-Newton observations, the new Chandra observation shows that the flux increase at short wavelengths and the decrease at long wavelengths do not necessarily occur simultaneously.Comment: To be published in the Astrophysical Journal Letters. Contains 4 pages with 3 figures, including 1 color figur

Do you need experts in the crowd? A case study in image annotation for marine biology

Labeled data is a prerequisite for successfully applying machine learning techniques to a wide range of problems. Recently, crowd-sourcing has shown to provide effective solutions to many labeling tasks. However, tasks in specialist domains are difficult to map to Human Intelligence Tasks (or HITs) that can be solved adequately by "the crowd". The question addressed in this paper is whether these specialist tasks can be cast in such a way, that accurate results can still be obtained through crowd-sourcing. We study a case where the goal is to identify fish species in images extracted from videos taken by underwater cameras, a task that typically requires profound domain knowledge in marine biology and hence would be difficult, if not impossible, for the crowd. We show that by carefully converting the recognition task to a visual similarity comparison task, the crowd achieves agreement with the experts comparable to the agreement achieved among experts. Further, non-expert users can learn and improve their performance during the labeling process, e.g., from the system feedback

Searching for ring-like structures in the Cosmic Microwave Background

In this research we present a new methodology to search for ring-like structures in the CMB. The particular context of this work is to investigate the presence of possible observational effects associated with Conformal Cyclic Cosmology (CCC), known as Hawking points. Although our results are not conclusive due to the statistical disagreement between the CMB sky map and the simulated sky maps in accordance to $\Lambda CDM$, we are able to retrieve ring-like anomalies from an artificial data at $95 \%$ confidence level. Once this discrepancy has been assessed, our method may be able to provide evidence of the presence or absence of Hawking points in the CMB. Hence, we stress the need to continue the theoretical and experimental research in this direction

Manipulating social roles in a tagging environment

Social roles structure daily life because people adjust their behavior according to the role that they have in a specific situation. Online social roles are not necessarily the same as those in daily life and, because they are not so strictly assigned, the question arises whether they can be manipulated. We conducted a structured experiment to investigate whether the manipulation of online social roles can affect user behavior in a tagging task

Implicit relevance feedback from a multi-step search process: a use of query-logs

We evaluate the use of clickthrough information as implicit relevance feedback in sessions. We employ records of user interactions with a search system for pictures retrieval: issued queries, clicked images, and purchased content; we investigate whether and how much of the past search history should be used in a feedback loop. We also assess the benefit of using clicked data as positive tokens of relevance to the task of estimating the probability of an image to be purchased

Quantum Machine Learning for bb-jet charge identification

Machine Learning algorithms have played an important role in hadronic jet classification problems. The large variety of models applied to Large Hadron Collider data has demonstrated that there is still room for improvement. In this context Quantum Machine Learning is a new and almost unexplored methodology, where the intrinsic properties of quantum computation could be used to exploit particles correlations for improving the jet classification performance. In this paper, we present a brand new approach to identify if a jet contains a hadron formed by a $b$ or $\bar{b}$ quark at the moment of production, based on a Variational Quantum Classifier applied to simulated data of the LHCb experiment. Quantum models are trained and evaluated using LHCb simulation. The jet identification performance is compared with a Deep Neural Network model to assess which method gives the better performance

The gut wall's potential as a partner for precision oncology in immune checkpoint treatment

The gut wall is the largest immune organ and forms a barrier through which gut microbiota interact with the immune system in the rest of the body. Gut microbiota composition plays a role in the strength and timing of the anticancer immune response on immune checkpoint inhibitors (ICI). Surprisingly, the effects of gut wall characteristics, such as physical barrier integrity, permeability, and activity and composition of the intestinal immune system, on response to ICI has received little attention. Here, we provide an overview of markers to characterize the gut wall and interventions that can modulate these gut wall characteristics. Finally, we present a future perspective on how these gut wall markers and interventions might be utilized and studied to improve ICI treatment strategies

Querylog-based assessment of retrievability bias in a large newspaper corpus

Bias in the retrieval of documents can directly influence the information access of a digital library. In the worst case, systematic favoritism for a certain type of document can render other parts of the collection invisible to users. This potential bias can be evaluated by measuring the retrievability for all documents in a collection. Previous evaluations have been performed on TREC collections using simulated query sets. The question remains, however, how representative this approach is of more realistic settings. To address this question, we investigate the effectiveness of the retrievability measure using a large digitized newspaper corpus, featuring two characteristics that distinguishes our experiments from previous studies: (1) compared to TREC collections, our collection contains noise originating from OCR processing, historical spelling and use of language; and (2) instead of simula