8 research outputs found
Cataclysmic variables from a ROSAT/2MASS selection. I, Four new intermediate polars
Get PDFWe report the first results from a new search for cataclysmic variables (CVs) using a combined X-ray (ROSAT)/infrared (2MASS) target selection that discriminates against background active galactic nuclei. Identification spectra were obtained at the Isaac Newton Telescope for a total of 174 targets, leading to the discovery of 12 new CVs. Initially devised to find short-period low-mass-transfer CVs, this selection scheme has been very successful in identifying new intermediate polars. Photometric and spectroscopic follow-up observations identify four of the new CVs as intermediate polars: 1RXS J063631.9+353537 P(orb)similar or equal to 201 min, P-spin= 1008.3408 s or 930.5829 s), 1RXS J070407.9+262501 (P(orb)similar or equal to 250 min, P-spin= 480.708 s) 1RXS J173021.5-055933 (P-orb= 925.27 min, P-spin= 128.0 s), and 1RXS J180340.0+401214 (P-orb= 160.21 min, P-spin= 1520.51 s). RX J1730, also a moderately bright hard X-ray source in the INTEGRAL/IBIS Galactic plane survey, resembles the enigmatic AE Aqr. It is likely that its white dwarf is not rotating at the spin equilibrium period, and the system may represent a short-lived phase in CV evolution
Intra-abdominal pressure alterations after large pancreatic pseudocyst transcutaneous drainage
No full textAbstract Background Acute pancreatitis leads to abdominal hypertension and compartment syndrome. Weeks after the episodes pancreatic fluids sometimes organize to pseudocysts, fluid collections by or in the gland. Aims of the present study were to evaluate the intra-abdominal pressure (IAP) induced by large pancreatic pseudocysts and to examine the effect of their transcutaneous drainage on IAP. Methods Twenty seven patients with a pancreatic pseudocyst were included. Nine patients with pseudocysts greater than 1l (group A) had CT drainage and eighteen (volume less than 1l) were the control group. The measurements of group A were taken 6 hours before and every morning after the drainage, while for group B, two measurements were performed, one at the day of the initial CT and one 7 days after. Abdominal compliance (Cabd) was calculated. Data were analyzed using student's t-test. Results Baseline IAP for group A was 9.3 mmHg (S.D. 1.7 mmHg), while the first post-drainage day (PDD) IAP was 5.1 mmHg (S.D. 0.7 mmHg). The second PDD IAP was 5.6 mmHg (S.D. 0.8 mmHg), the third 6.4 mmH (S.D. 1.2 mmHg)g, the fourth 6.9 mmHg (S.D. 1.6 mmHg), the fifth 7.9 mmHg (S.D. 1.5 mmHg), the sixth 8.2 mmHg (S.D. 1.4 mmHg), and the seventh 8.2 mmHg (S.D. 1.5 mmHg). Group B had baseline IAP 8.0 mmHg (S.D. 1.2 mmHg) and final 8.2 mmHg (S.D. 1.4 mmHg). Cabd after drainage was 185.6 ml/mmHg (SD 47.5 ml/mmHg). IAP values were reduced between the baseline and all the post-drainage measurements in group A. IAPs seem to stabilize after the 5th post-drainage day. Baseline IAP was higher in group A than in group B, while the two values, at day 7, were equivalent. Conclusion The drainage of large pancreatic pseudocyst reduces IAP. Moreover, the IAP seems to rise shortly after the drainage again, but in a way that it remains inferior to the initial value. More chronic changes to the IAP are related to abdominal cavity's properties and have to be further studied.</p
A signature of the donor star in the extra-galactic X-ray binary LMC X-2
Get PDFTwo nights of phase-resolved medium-resolution Very Large Telescope spectroscopy of the extra-galactic low-mass X-ray binary LMCX-2 have revealed a 0.32 +/- 0.02 d spectroscopic period in the radial velocity curve of the He II lambda 4686 emission line that we interpret as the orbital period. However, similar to previous findings, this radial velocity curve shows a longer term variation that is most likely due to the presence of a precessing accretion disc in LMCX-2. This is strengthened by He II lambda 4686 Doppler maps that show a bright spot that is moving from night to night. Furthermore, we detect narrow emission lines in the Bowen region of LMCX-2, with a velocity of K-em = 351 +/- 28 km s(-1), that we tentatively interpret as coming from the irradiated side of the donor star. Since K-em must be smaller than K-2, this leads to the first upper limit on the mass function of LMCX-2 of f(M-1) >= 0.86 M-circle dot (95 per cent confidence), and the first constraints on its system parameters
Anterior chest wall tuberculous abscess: a case report
No full textAbstract The granulomatous inflammation of tuberculosis usually involves the lungs and the hilar lymph nodes. Musculoskeletal tuberculosis (TB) occurs in 1–3% of patients with TB, while TB of the chest wall constitutes 1% to 5% of all cases of musculoskeletal TB. Furthermore, nowadays it is rarer to find extrapulmonary TB in immunocompetent rather that non-immunocompetent patients. The present case reports a fifty-six-year-old immunocompetent man with an anterior chest wall tuberculous abscess. The rarity of the present case relates both to the localization of the tuberculous abscess, and to the fact that the patient was immunocompetent. The diagnosis of musculoskeletal tuberculous infection remains a challenge for clinicians and requires a high index of suspicion. The combination of indolent onset of symptoms, positive tuberculin skin test, and compatible radiographic findings, strongly suggests the diagnosis. TB, however, must be confirmed by positive culture or histologic proof. Prompt diagnosis and treatment are important to prevent serious bone and joint destruction.</p
Hematemesis, a very rare presentation of solid pseudo-papillary tumors of the pancreas: a case report
No full textAbstract Introduction Solid pseudo-papillary tumors of the pancreas are rare and typically present in young female patients. They are slowly growing masses that may attain large size, and are of low malignant potential. Surgical resection is usually curative. Case presentation A 71-year-old woman presented to the emergency department with an episode of hematemesis but was otherwise hemodynamically stable. Emergency gastroscopy revealed a bleeding mass projecting to the duodenum. Fluid, blood and electrolyte resuscitation followed. Computed tomography revealed a small mass in the head of the pancreas. A Whipple operation was performed. Pathology revealed a solid pseudo-papillary tumor. The postoperative course of the patient was uneventful and no recurrence was present a year after the operation. Conclusion In our case, the most noteworthy observations concern the small size of the tumor, the age of the patient and the presenting symptom. However, pancreaticoduodenectomy in a 71-year-old woman is a major effort and should only be undertaken by centers and surgeons experienced in complex hepatobiliary surgery. Furthermore, the unique nature of this case reminds every clinician that each patient has to be considered separately and with extreme caution.</p
High time resolution optical/X-ray cross-correlations for X-ray binaries : anticorrelations and rapid variability
Get PDFUsing simultaneous observations in X-rays and optical, we have performed a homogeneous analysis of the cross-correlation behaviours of four X-ray binaries: SWIFT J1753.5-0127, GX339-4, Sco X-1 and CygX-2. With high-time-resolution observations using ULTRACAM and RXTE, we concentrate on the short time-scale, delta t < 20 s, variability in these sources. Here we present our data base of observations, with three simultaneous energy bands in both the optical and the X-ray, and multiple epochs of observation for each source, all with similar to second or better time resolution. For the first time, we include a dynamical cross-correlation analysis, i.e. an investigation of how the cross-correlation function changes within an observation. We describe a number of trends which emerge. We include the full data set of results, and pick a few striking relationships from among them for further discussion.
We find, that the surprising form of X-ray/optical cross-correlation functions, a positive correlation signal preceded by an anticorrelation signal, is seen in all the sources at least some of the time. Such behaviour suggests a mechanism other than reprocessing as being the dominant driver of the short-term variability in the optical emission. This behaviour appears more pronounced when the X-ray spectrum is hard. Furthermore, we find that the cross-correlation relationships themselves are not stable in time, but vary significantly in strength and form. This all hints at dynamic interactions between the emitting components which could be modelled through non-linear or differential relationships
