52 research outputs found

    Pelvic actinomycosis presenting as a malignant pelvic mass: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Pelvic actinomycosis constitutes 3% of all human actinomycosis infections. It is usually insidious, and is often mistaken for other conditions such as diverticulitis, abscesses, inflammatory bowel disease and malignant tumors, presenting a diagnostic challenge pre-operatively; it is identified post-operatively in most cases. Here we present a case that presented as pelvic malignancy and was diagnosed as pelvic actinomycosis post-operatively.</p> <p>Case presentation</p> <p>A 48-year-old Caucasian Turkish woman presented to our clinic with a three-month history of abdominal pain, weight loss and difficulty in defecation. She had used an intra-uterine device for 16 years, however it had recently been removed. The rectosigmoidoscopy revealed narrowing of the lumen at 12 cm due to a mass lesion either in the wall or due to an extrinsic lesion that prevented the passage of the endoscope. On examination, there was no gynecological pathology. Magnetic resonance imaging showed a mass, measuring 5.5 × 4 cm attached to the rectum posterior to the uterus. The ureter on that side was dilated. Surgically there was a pelvic mass adhered to the rectum and uterine adnexes, measuring 10 × 12 cm. It originated from uterine adnexes, particularly ones from the left side and formed a conglomerated mass with the uterus and nearby organs; the left ureter was also dilated due to the pelvic mass. Because of concomitant tubal abscess formation and difficulty in dissection planes, total abdominal hysterectomy and bilateral salphingo-oophorectomy was performed (our patient was 48 years old and had completed her childbearing period). The cytology revealed inflammatory cells with aggregates of <it>Actinomyces</it>. Penicillin therapy was given for six months without any complication.</p> <p>Conclusions</p> <p>Pelvic actinomycosis should always be considered in patients with a pelvic mass especially in ones using intra-uterine devices, and who have a history of appendectomy, tonsillectomy or dental infection. Surgeons should be aware of this infection in order to avoid excessive surgical procedures.</p

    Social networks in changing environments

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    Social network analysis (SNA) has become a widespread tool for the study of animal social organisation. However despite this broad applicability, SNA is currently limited by both an overly strong focus on pattern analysis as well as a lack of dynamic interaction models. Here, we use a dynamic modelling approach that can capture the responses of social networks to changing environments. Using the guppy, Poecilia reticulata, we identified the general properties of the social dynamics underlying fish social networks and found that they are highly robust to differences in population density and habitat changes. Movement simulations showed that this robustness could buffer changes in transmission processes over a surprisingly large density range. These simulation results suggest that the ability of social systems to self-stabilise could have important implications for the spread of infectious diseases and information. In contrast to habitat manipulations, social manipulations (e.g. change of sex ratios) produced strong, but short-lived, changes in network dynamics. Lastly, we discuss how the evolution of the observed social dynamics might be linked to predator attack strategies. We argue that guppy social networks are an emergent property of social dynamics resulting from predator–prey co-evolution. Our study highlights the need to develop dynamic models of social networks in connection with an evolutionary framework

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources

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    The HAWC Collaboration released the 2HWC catalogue of TeV sources, in which 19 show no association with any known high-energy (HE; E greater than or similar to 10 GeV) or very-high-energy (VHE; E greater than or similar to 300 GeV) sources. This catalogue motivated follow-up studies by both the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) and Fermi-LAT (Large Area Telescope) observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between High Altitude Water Cherenkov (HAWC), MAGIC, and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084*, and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degrees extension (at 95 per cent confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, whilst a simply minimum extension of 0.16 degrees (at 95 per cent confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail
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