We present the results of spectroscopic, narrow-band and X-ray observations of a z= 2.30 protocluster in the field of the QSO HS 1700+643. Using a sample of BX/MD galaxies, which are selected to be ...at z∼ 2.2–2.7 by their rest-frame ultraviolet colours, we find that there are five protocluster AGN which have been identified by characteristic emission-lines in their optical/near-IR spectra; this represents an enhancement over the field significant at >98.5 per cent confidence. Using a ∼200-ks Chandra/ACIS-I observation of this field we detect a total of 161 X-ray point sources to a Poissonian false-probability limit of 4 × 10−6 and identify eight of these with BX/MD galaxies. Two of these are spectroscopically confirmed protocluster members and are also classified as emission-line AGN. When compared to a similarly selected field sample, the analysis indicates this is also evidence for an enhancement of X-ray selected BX/MD AGN over the field, significant at >99 per cent confidence. Deep Lyα narrow-band imaging reveals that a total of 4/123 Lyα emitters (LAEs) are found to be associated with X-ray sources, with two of these confirmed protocluster members and one highly likely member. We do not find a significant enhancement of AGN activity in this LAE sample over that of the field (result is significant at only 87 per cent confidence). The X-ray emitting AGN fractions for the BX/MD and LAE samples are found to be 6.9+9.2−4.4 and 2.9+2.9−1.6 per cent, respectively, for protocluster AGN with L2-10 keV≥ 4.6 × 1043 erg s−1 at z= 2.30. These findings are similar to results from the z= 3.09 protocluster in the SSA 22 field found by Lehmer et al. (2009), in that both suggest AGN activity is favoured in dense environments at z > 2.
Previous studies have shown that the disturbance of redox homeostasis plays a role in the pathogenesis of mood disorders. It is currently unclear whether oxidative stress parameters can be used as ...biomarkers (state vs. trait). The aim of the present study was to investigate oxidative stress markers in patients with major depressive disorder (MDD) and bipolar disorder (BP) in acute depressive episodes and remission, and healthy individuals.
Thirty-two patients with a diagnosis of MDD, 32 patients with a diagnosis of BP and 32 matched healthy controls were included in the study. We measured the serum levels of markers of oxidative damage, including 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-Iso-prostaglandin F2α (8-iso-PGF2α; 8-isoprostane), and malondialdehyde (MDA), and also serum activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR) in both acute and remission phase, and in control group.
After controlling for the effects of age, sex, body mass index, and smoking status, serum 8-iso-PGF2α levels were significantly higher in both patient groups compared to controls, regardless of disease phase. The activities of GPX and GR were significantly lower in the acute phase in MDD patients compared to controls. Serum GR activity was lower in both acute and remission phase in MDD compared to BP.
Our results suggest that both MDD and BP are associated with a disturbed redox balance with a particularly pronounced increase in serum 8-iso-PGF2α levels in both groups and the presence of glutathione metabolism disorders in MDD patients. Further research is needed to confirm the importance of oxidative stress parameters as potential biomarkers of MDD and BP.
Observations of QSOs at
z
∼
5.7–6.4 show the appearance of Gunn–Peterson troughs around
z
∼
6, and a change in the slope of the IGM optical depth
τ(
z) near
z
∼
5.5. These results are interpreted as ...a signature of the end of the reionization era, which probably started at considerably higher redshifts. However, there also appears to be a substantial cosmic variance in the transmission of the IGM, both along some lines of sight, and among different lines of sight, in this intriguing redshift regime. We suggest that this is indicative of a spatially uneven reionization, possibly caused by the bias-driven primordial clustering of the reionization sources. There is also some independent evidence for a strong clustering of QSOs at
z
∼
4–5 and galaxies around them, supporting the idea of the strong biasing of the first luminous sources at these redshifts. Larger samples of high-
z QSOs are needed in order to provide improved, statistically significant constraints for the models of these phenomena. We expect that the Palomar-Quest (PQ) survey will soon provide a new set of QSOs to be used as cosmological probes in this redshift regime.
The aim of investigation was to assess the role of somatostatin receptor
scintigraphy in diagnosis and follow-up of pancreatic neuroendocrine
neoplasms. Somatostatin receptor scintigraphy was ...performed with 740 MBq
99mTc-EDDA/HYNIC TOC for diagnosis of primary tumors and follow-up after
the therapy. There were 63 true positive, 24 true negative, 4 false
positive, and 6 false negative findings. Sensitivity was 91.3 %, specificity
85.7 %, positive predictive value 94.0 %, negative predictive value 80.0 %,
accuracy 89.7 %. The SPECT contributed diagnosis in 28 true positive
findings. In 32 patients (33 %) somatostatin receptor scintigraphy
significantly changed the management of the patients (10 had surgery, in 17
somatostatin analogues, and in 5 peptide receptor radionuclide therapy was
introduced). Mean Ki-67 index in true positive patients was 13.8 ?5.0 %
while in true negative 7.1 ? 3.4% which is significantly lower at p < 0.05. There
was significantly (p < 0.01) higher number of increased chromogranin A
values in true positive than in true negative patients (p = 0.000857). Our
results confirmed the value of SRS in the diagnosis and follow-up of the patients with pancreatic neuroendocrine neoplasms PanNEN if primary tumors, recurrences or metastases are suspected, as well as for appropriate
choice of the therapy.
In this paper, the switched nonuniform polar quantization is asymptotically analyzed for the case when the power of an input signal varies in a wide range. We observed two compression functions: ...logarithmic and optimum. For the suggested quantizer model we optimized the granular distortion in order to obtain the manner of the total distribution of points, i.e., we evaluated the expressions for the amplitude-level number and the phase-level number for on one amplitude level. In addition, we found the expression for granular distortion, which we used to estimate the suggested model. We compared the numerically obtained results with the G711 and G712 standards, and on these bases, we derived conclusions about the possibilities of this switched quantization application in speech processing. The suggested quantizer can be used for data compression where the saving can reach 1.5 bits/sample. This circumstance means that the technique that we presented in the paper can be applied for voice transmission over the Internet (VoIP) and in public switched telephone networks (PSTN).PUBLICATION ABSTRACT
We present observations of an optically faint quasar, RD J114816.2+525339 (hereafter RD J1148+5253), discovered from deep multicolor observations of the field around the z = 6.42 quasar SDSS ...J1148+5251. The two quasars have a projected separation of 109 and both are outliers in r - z versus z - J color-color space. Keck spectroscopy reveals RD J1148+5253 to be a broad absorption line quasar at z = 5.70. With z sub(AB) = 23.0, RD J1148+5253 is 3.3 mag fainter than SDSS J1148+5251, making it the faintest quasar known at z > 5.5. This object was identified in a survey of -2.5 deg super(2). The implied surface density of quasars at these redshifts and luminosities is broadly consistent with previous extrapolations of the faint end of the quasar luminosity function and supports the idea that active galaxies provide only a minor component of the reionizing ultraviolet flux at these redshifts.
We report the discovery of two low-luminosity quasars at z 6 4, both of which show prominent N IV l1486 emission. This line is extremely rare in quasar spectra at any redshift; detecting it in two of ...a sample of 23 objects (i.e., 69% of the sample) is intriguing and is likely due to the low-luminosity, high-redshift quasar sample we are studying. This is still a poorly explored regime, where contributions from associated, early starbursts may be significant. One Interpretation of this line posits photoionization by very massive young stars. Seeing N IV l1486 emission in a high-redshift quasar may thus be understood in the context of coformation and early coevolution of galaxies and their supermassive black holes. Alternatively, we may be seeing a phenomenon related to the early evolution of quasar broad emission line regions. The nondetection (and possibly even broad absorption) of N v l1240 line in the spectrum of one of these quasars may support that interpretation. These two objects may signal a new faint quasar population or an early AGN evolutionary stage at high redshifts.
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