9,155 research outputs found

    The SW Sex-type star 2MASS J01074282+4845188: an unusual bright accretion disk with non-steady emission and a hot white dwarf

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    We present new photometric and spectral observations of the newly discovered nova-like eclipsing star 2MASS J01074282+4845188. To obtain a light curve solution we used model of a nova-like star whose emission sources are a white dwarf surrounded by an accretion disk, a secondary star filling its Roche lobe, a hot spot and a hot line. 2MASS J01074282+4845188 shows the deepest permanent eclipse among the known nova-like stars. It is reproduced by covering the very bright accretion disk by the secondary component. The luminosity of the disk is much bigger than that of the rest light sources. The determined high temperature of the disk is typical for that observed during the outbursts of CVs. The primary of 2MASS J01074282+4845188 is one of the hottest white dwarfs in CVs. The temperature of 5090 K of its secondary is also quite high and more appropriate for a long-period SW Sex star. It might be explained by the intense heating from the hot white dwarf and the hot accretion disk of the target. The high mass accretion rate \dot{M} = 8\times 10^{-9} M_{\sun} yr−1^{-1}, the broad and single-peaked Hα\alpha emission profile, and the presence of an S-wave are sure signs for the SW Sex classification of 2MASS J01074282+4845188. The obtained flat temperature distribution along the disk radius as well as the deviation of the energy distribution from the black-body law are evidence of the non-steady emission of the disk. The close values of the disk temperature and the parameter αg\alpha_{g} of 2MASS J01074282+4845188 and those of the cataclysmic stars at eruptions might be considered as an additional argument for the permanent active state of nova-like stars.Comment: 11 pages, 11 figures, 5 tables. Accepted for publication in A&

    Self-supporting liberals and their cliques : an axiomatic characterization

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    social groupssocial status;social choice

    Cerebral malaria admissions in Papua New Guinea may show inter-annual cyclicity: An example of about a 1.5-year cycle for malaria incidence in Burundi

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    Best available descriptions of malaria incidence and mortality dynamics are important to better plan and evaluate the implementation of programs to monitor (e.g., remote sensing) and control the disease, especially in endemic zones. This was stressed recently by Cibulskis et al (2007) in the view of completeness of monthly reporting for cerebral malaria admissions in Papua New Guinea (latitude 6 degree S, 1987-1996). Notably, regardless of the rate of its completeness, the temporal dynamics of admissions was preserved over the years, however, neither raw data nor results on further analyses about eventual inter-annual cyclic components (periods T>1 year) were provided despite obvious graphical patterns for such a specific time structure (chronome). Interestingly, in a recent analysis by Gomez-Elipe et al (2007) on monthly malaria notifications in Burundi, at almost the same latitude (province of Karuzi, >3 degree S, 1997-2001), the data have shown neither trend not periodic oscillations beyond a 6-month (0.5-year) period. Since the graphical representation of both data sets have indicated an eventual existence of inter-annual variations, and because both are located at the same latitude zone, we have further analyzed the data from Burundi for such periodic oscillations. By using a periodogram regression analysis, we discovered a multicomponent cyclic chronome with periods above 12 months (T=17.5-18.0, 27.5 and 65.0-65.5 months, all at p<0.05). Notably, the most strong cyclic pattern at p<0.002 in the periodogram of the detrended malaria rates in Burundi remained only that with a peak at about 1.5 years (period T=17.5-18.0 months, R=0.51, z=5.3). It is possible that likely inter-annual cyclic patterns might exist also in the time structure for cerebral malaria admissions in Papua New Guinea and, if confirmed, these may be found very useful in epidemic forecasting and programs implementation. We explored these cyclic variations and also discussed possible associations with environmental factors exhibiting alike cyclicity

    Therapeutic antibodies: current state and future trends--is a paradigm change coming soon?

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    Antibody-based therapeutics currently enjoy unprecedented success, growth in research and revenues, and recognition of their potential. It appears that the promise of the "magic bullet" has largely been realized. There are currently 22 monoclonal antibodies (mAbs) approved by the United States Food and Drug Administration (FDA) for clinical use and hundreds are in clinical trials for treatment of various diseases including cancers, immune disorders, and infections. The revenues from the top five therapeutic antibodies (Rituxan, Remicade, Herceptin, Humira, and Avastin) nearly doubled from 6.4billionin2004to6.4 billion in 2004 to 11.7 billion in 2006. During the last several years major pharmaceutical companies raced to acquire antibody companies, with a recent example of MedImmune being purchased for $15.6 billion by AstraZeneca. These therapeutic and business successes reflect the major advances in antibody engineering which have resulted in the generation of safe, specific, high-affinity, and non-immunogenic antibodies during the last three decades. Currently, second and third generations of antibodies are under development, mostly to improve already existing antibody specificities. However, although the refinement of already known methodologies is certainly of great importance for potential clinical use, there are no conceptually new developments in the last decade comparable, for example, to the development of antibody libraries, phage display, domain antibodies (dAbs), and antibody humanization to name a few. A fundamental question is then whether there will be another change in the paradigm of research as happened 1-2 decades ago or the current trend of gradual improvement of already developed methodologies and therapeutic antibodies will continue. Although any prediction could prove incorrect, it appears that conceptually new methodologies are needed to overcome the fundamental problems of drug (antibody) resistance due to genetic or/and epigenetic alterations in cancer and chronic infections, as well as problems related to access to targets and complexity of biological systems. If new methodologies are not developed, it is likely that gradual saturation will occur in the pipeline of conceptually new antibody therapeutics. In this scenario we will witness an increase in combination of targets and antibodies, and further attempts to personalize targeted treatments by using appropriate biomarkers as well as to develop novel scaffolds with properties that are superior to those of the antibodies now in clinical use

    Egalitarianism in convex fuzzy games

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    cooperative games;algorithm
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