483 research outputs found
Five supernova survey galaxies in the southern hemisphere. I. Optical and near-infrared database
The determination of the supernova (SN) rate is based not only on the number
of detected events, but also on the properties of the parent galaxy population.
This is the first paper of a series aimed at obtaining new, refined, SN rates
from a set of five SN surveys, by making use of a joint analysis of
near-infrared (NIR) data. We describe the properties of the 3838 galaxies that
were monitored for SNe events, including newly determined morphologies and
their DENIS and POSS-II/UKST I, 2MASS and DENIS J and Ks and 2MASS H
magnitudes. We have compared 2MASS, DENIS and POSS-II/UKST IJK magnitudes in
order to find possible systematic photometric shifts in the measurements. The
DENIS and POSS-II/UKST I band magnitudes show large discrepancies (mean
absolute difference of 0.4 mag), mostly due to different spectral responses of
the two instruments, with an important contribution (0.33 mag rms) from the
large uncertainties in the photometric calibration of the POSS-II and UKST
photographic plates. In the other wavebands, the limiting near infrared
magnitude, morphology and inclination of the galaxies are the most influential
factors which affect the determination of photometry of the galaxies.
Nevertheless, no significant systematic differences have been found between of
any pair of NIR magnitude measurements, except for a few percent of galaxies
showing large discrepancies. This allows us to combine DENIS and 2MASS data for
the J and Ks filters.Comment: 17 pages, 3 figures, 5 tables, published in Astrophysics, Vol. 52,
No. 1, 2009 (English translation of Astrofizika
Galaxies and Cladistics
The Hubble tuning fork diagram, based on morphology and established in the
1930s, has always been the preferred scheme for classification of galaxies.
However, the current large amount of multiwavelength data, most often spectra,
for objects up to very high distances, asks for more sophisticated statistical
approaches. Interpreting formation and evolution of galaxies as a ?transmission
with modification' process, we have shown that the concepts and tools of
phylogenetic systematics can be heuristically transposed to the case of
galaxies. This approach, which we call ?astrocladistics', has successfully been
applied on several samples. Many difficulties still remain, some of them being
specific to the nature of both galaxies and their diversification processes,
some others being classical in cladistics, like the pertinence of the
descriptors in conveying any useful evolutionary information.Comment: Talk given at the "12th Evolutionary Biology Meeting" held in
Marseille, France, Sept. 24-26, 200
Quaternary vertebrate faunas from Sumba, Indonesia: implications for Wallacean biogeography and evolution
Historical patterns of diversity, biogeography and faunal turnover remain poorly understood for Wallacea, the biologically and geologically complex island region between the Asian and Australian continental shelves. A distinctive Quaternary vertebrate fauna containing the small-bodied hominin Homo floresiensis, pygmy Stegodon proboscideans, varanids and giant murids has been described from Flores, but Quaternary faunas are poorly known from most other Lesser Sunda Islands. We report the discovery of extensive new fossil vertebrate collections from Pleistocene and Holocene deposits on Sumba, a large Wallacean island situated less than 50 km south of Flores. A fossil assemblage recovered from a Pleistocene deposit at Lewapaku in the interior highlands of Sumba, which may be close to 1 million years old, contains a series of skeletal elements of a very small Stegodon referable to S. sumbaensis, a tooth attributable to Varanus komodoensis, and fragmentary remains of unidentified giant murids. Holocene cave deposits at Mahaniwa dated to approximately 2000–3500 BP yielded extensive material of two new genera of endemic large-bodied murids, as well as fossils of an extinct frugivorous varanid. This new baseline for reconstructing Wallacean faunal histories reveals that Sumba's Quaternary vertebrate fauna, although phylogenetically distinctive, was comparable in diversity and composition to the Quaternary fauna of Flores, suggesting that similar assemblages may have characterized Quaternary terrestrial ecosystems on many or all of the larger Lesser Sunda Islands
Simultaneous localization of MLL, AF4 and ENL genes in interphase nuclei by 3D-FISH: MLL translocation revisited
BACKGROUND: Haematological cancer is characterised by chromosomal translocation (e.g. MLL translocation in acute leukaemia) and two models have been proposed to explain the origins of recurrent reciprocal translocation. The first, established from pairs of translocated genes (such as BCR and ABL), considers the spatial proximity of loci in interphase nuclei (static "contact first" model). The second model is based on the dynamics of double strand break ends during repair processes (dynamic "breakage first" model). Since the MLL gene involved in 11q23 translocation has more than 40 partners, the study of the relative positions of the MLL gene with both the most frequent partner gene (AF4) and a less frequent partner gene (ENL), should elucidate the MLL translocation mechanism. METHODS: Using triple labeling 3D FISH experiments, we have determined the relative positions of MLL, AF4 and ENL genes, in two lymphoblastic and two myeloid human cell lines. RESULTS: In all cell lines, the ENL gene is significantly closer to the MLL gene than the AF4 gene (with P value < 0.0001). According to the static "contact first" model of the translocation mechanism, a minimal distance between loci would indicate a greater probability of the occurrence of t(11;19)(q23;p13.3) compared to t(4;11)(q21;q23). However this is in contradiction to the epidemiology of 11q23 translocation. CONCLUSION: The simultaneous multi-probe hybridization in 3D-FISH is a new approach in addressing the correlation between spatial proximity and occurrence of translocation. Our observations are not consistent with the static "contact first" model of translocation. The recently proposed dynamic "breakage first" model offers an attractive alternative explanation
Analysis of a sprint ski race and associated laboratory determinants of world-class performance
This investigation was designed to analyze the time-trial (STT) in an international cross-country skiing sprint skating competition for (1) overall STT performance and relative contributions of time spent in different sections of terrain, (2) work rate and kinematics on uphill terrain, and (3) relationships to physiological and kinematic parameters while treadmill roller ski skating. Total time and times in nine different sections of terrain by 12 world-class male sprint skiers were determined, along with work rate and kinematics for one specific uphill section. In addition, peak oxygen uptake (VO2peak), gross efficiency (GE), peak speed (Vpeak), and kinematics in skating were measured. Times on the last two uphill and two final flat sections were correlated to overall STT performance (r = ~−0.80, P < 0.001). For the selected uphill section, speed was correlated to cycle length (r = −0.75, P < 0.01) and the estimated work rate was approximately 160% of peak aerobic power. VO2peak, GE, Vpeak, and peak cycle length were all correlated to STT performance (r = ~−0.85, P < 0.001). More specifically, VO2peak and GE were correlated to the last two uphill and two final flat section times, whereas Vpeak and peak cycle length were correlated to times in all uphill, flat, and curved sections except for the initial section (r = ~−0.80, P < 0.01). Performances on uphill and flat terrain in the latter part were the most significant determinants of overall STT performance. Peak oxygen uptake, efficiency, peak speed, and peak cycle length were strongly correlated to overall STT performance, as well as to performance in different sections of the race
Patients' and urologists' preferences for prostate cancer treatment: A discrete choice experiment
__Abstract__
Background: Patients' preferences are important for shared decision making. Therefore, we investigated patients' and urologists' preferences for treatment alternatives for early prostate cancer (PC). Methods: A discrete choice experiment was conducted among 150 patients who were waiting for their biopsy results, and 150 urologists. Regression analysis was used to determine patients' and urologists' stated preferences using scenarios based on PC treatment modality (radiotherapy, surgery, and active surveillance (AS)), and risks of urinary incontinence and erectile dysfunction.Results:The response rate was 110 out of 150 (73%) for patients and 50 out of 150 (33%) for urologists. Risk of urinary incontinence was an important determinant of both patients' and urologists' stated preferences for PC treatment (P<0.05). Treatment modality also influenced patients' stated preferences (P<0.05), whereas the risk of erectile dysfunction due to radiotherapy was mainly important to urologists (P<0.05). Both patients and urologists preferred AS to radical treatment, with the exception of patients with anxious/depressed feelings who preferred radical treatment to AS. Conclusion: Although patients and urologists generally may prefer similar treatments for PC, they showed different trade-offs between various specific treatment aspects. This implies that urologists need to be aware of potential differences compared with the patient's perspective on treatment decisions in shared decision making on PC treatment
Intraneural synovial sarcoma of the median nerve
Synovial sarcomas are soft-tissue malignancies with a poor prognosis and propensity for distant metastases. Although originally believed to arise from the synovium, these tumors have been found to occur anywhere in the body. We report a rare case of synovial sarcoma arising from the median nerve. To our knowledge, this is the twelfth reported case of intraneural synovial sarcoma, and only the fourth arising from the median nerve. Because the diagnosis may not be apparent until after pathological examination of the surgical specimen, synovial sarcoma should be kept in mind when dealing with what may seem like a benign nerve tumor
Capacitative calcium influx and proliferation of human osteoblastic-like MG-63 cells
Adult bone tissue is continuously being remodelled and bone mass is maintained by a balance between osteoclastic bone resorption and osteoblastic bone formation. Alteration of osteoblastic cell proliferation may account in part for lack of balance between these two processes in bone loss of osteoporosis. There is calcium (Ca2+) control in numerous cellular functions; however, involvement of capacitative Ca2+ entry (CCE) in proliferation of bone cells is less well investigated. OBJECTIVES: The study described here was aimed to investigate roles of CCE in the proliferation of osteoblast-like MG-63 cells. MATERIALS AND METHODS: Pharmacological characterizations of CCE were undertaken in parallel, with evaluation of the expression of transient receptor potential canonical (TRPC) channels and of cell proliferation. RESULTS: Intracellular Ca2+ store depletion by thapsigargin induced CCE in MG-63 cells; this was characterized by a rapid transient increase of intracellular Ca2+ followed by significant CCE, induced by conditions that stimulated cell proliferation, namely serum and platelet-derived growth factor. Inhibitors of store-operated Ca2+ channels (2-APB and SKF-96365) prevented CCE, while voltage-dependent Ca2+ channel blockers had no effect. Expression of various TRPC channels was shown in the cells, some having been shown to be responsible for CCE. Voltage-dependent Ca2+ channel blockers had no effect on osteoblast proliferation while thapsigargin, 2-APB and SKF-96395, inhibited it. Cell cycle analysis showed that 2-APB and SKF-96395 lengthen the S and G2/M phases, which would account for the reduction in cell proliferation. CONCLUSIONS: Our results indicate that CCE, likely attributed to the activation of TRPCs, might be the main route for Ca2+ influx involved in osteoblast proliferation
Clinical outcomes in typhoid fever: adverse impact of infection with nalidixic acid-resistant Salmonella typhi
BACKGROUND: Widespread use of fluoroquinolones has resulted in emergence of Salmonella typhi strains with decreased susceptibility to fluoroquinolones. These strains are identifiable by their nalidixic acid-resistance. We studied the impact of infection with nalidixic acid-resistant S. typhi (NARST) on clinical outcomes in patients with bacteriologically-confirmed typhoid fever. METHODS: Clinical and laboratory features, fever clearance time and complications were prospectively studied in patients with blood culture-proven typhoid fever, treated at a tertiary care hospital in north India, during the period from November 2001 to October 2003. Susceptibility to amoxycillin, co-trimoxazole, chloramphenicol, ciprofloxacin and ceftriaxone were tested by disc diffusion method. Minimum inhibitory concentrations (MIC) of ciprofloxacin and ceftriaxone were determined by E-test method. RESULTS: During a two-year period, 60 patients (age [mean ± SD]: 15 ± 9 years; males: 40 [67%]) were studied. All isolates were sensitive to ciprofloxacin and ceftriaxone by disc diffusion and MIC breakpoints. However, 11 patients had clinical failure of fluoroquinolone therapy. Infections with NARST isolates (47 [78%]) were significantly associated with longer duration of fever at presentation (median [IQR] 10 [7-15] vs. 4 [3-6] days; P = 0.000), higher frequency of hepatomegaly (57% vs. 15%; P = 0.021), higher levels of aspartate aminotransferase (121 [66–235] vs. 73 [44–119] IU/L; P = 0.033), and increased MIC of ciprofloxacin (0.37 ± 0.21 vs. 0.17 ± 0.14 μg/mL; P = 0.005), as compared to infections with nalidixic acid-susceptible isolates. All 11 patients with complications were infected with NARST isolates. Total duration of illness was significantly longer in patients who developed complications than in patients who did not (22 [14.8–32] vs. 12 [9.3–20.3] days; P = 0.011). Duration of prior antibiotic intake had a strong positive correlation with the duration of fever at presentation (r = 0.61; P = 0.000) as well as the total duration of illness (r = 0.53; P = 0.000). CONCLUSION: Typhoid fever caused by NARST infection is associated with poor clinical outcomes, probably due to delay in initiating appropriate antibiotic therapy. Fluoroquinolone breakpoints for S. typhi need to be redefined and fluoroquinolones should no longer be used as first-line therapy, if the prevalence of NARST is high
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