Remarks on the origin of cerussite in the Upper Silesian Zn-Pb deposits, Poland

Cerussite, the most important oxidized lead mineral in the Upper Silesian Zn-Pb deposits, occurs in two readily distinct types: fine-grained cerussite replacing galena in-situ and macrocrystalline cerussite filling open fractures and cavities. Microscopic observations and thermodynamic considerations lead to the conclusion that galena can be oxidized to lead carbonate directly, not necessarily through an intermediate sulphate phase. Locally present iron sulphides undergoing oxidation acidify solutions and provide ferric ions which are important oxidizing agents. In such microenvironments, anglesite can preferentially form. Cerussite and galena commonly coexist together with non-oxidized zinc sulphides. It is difficult to explain such assemblages if galvanic couplings made of these two sulphides are not considered. These couplings are only formed when these two sulphides are in direct contact. In such an assemblage, galena undergoes oxidation, mostly to cerussite, and sphalerite is passivated. When there is no direct contact between sulphides, the galvanic couplings do not exist. Galena surfaces become covered by oxidation products which inhibit further oxidation. As such a cover does not form on sphalerite, it can be easily oxidized

Early growth of Scots pine, European larch and common oak at the young age on post-fire area located in the Sława Śląska Forest District (SW Poland)

The long-term forecasts predict that global warming will increase frequency and area of forest fires. Apart from economic losses resulting from a reduction of wood volume and annual increments of trees, the post-fire areas requiring the reforestation are enlarging considerably.            The present study aimed at the comparison of growth parameters of Scots pine, European larch and common oak seedlings growing on post-fire forest area with those growing in the control forest site established after clear cutting which was not enveloped by fire. We hypothesized that differences in growth traits of seedlings growing on post-fire area or in the control would depend on the species-specific ecological requirements. Among three study species Scots pine was selected to be the most suitable for planting on burnt area taking into account its growth traits and reforestation success.            Scots pine and European larch seedlings showed a greater thickness at root collar and pine had also a greater height on burnt area than in the control. Common oak responded inversely, it grew better in the control conditions compared with the burnt area. The pine grade of slenderness was similar in both treatments. Larch and oak reduced their grade of slenderness growing on post-fire area.Our results supported the hypothesis that the responses of the study trees to the burnt area conditions were determined by the species-dependent traits. The post-fire environment was the most favourable for light-demanding, pioneer pine and larch, but it was disadvantageous for late-successional, more conservative oak. Scots pine together with European larch are recommended to be planted on the burnt area to restore relatively fast the forest ecosystem. At the beginning of reforestation these species can play a role of pioneer crop and later will be able to become the dominant species together with less flammable broadleaved trees in the converted stands

Herschel PACS and SPIRE observations of blazar PKS 1510-089: a case for two blazar zones

We present the results of observations of blazar PKS 1510-089 with the Herschel Space Observatory PACS and SPIRE instruments, together with multiwavelength data from Fermi/LAT, Swift, SMARTS and SMA. The source was found in a quiet state, and its far-infrared spectrum is consistent with a power-law with a spectral index of alpha ~ 0.7. Our Herschel observations were preceded by two 'orphan' gamma-ray flares. The near-infrared data reveal the high-energy cut-off in the main synchrotron component, which cannot be associated with the main gamma-ray component in a one-zone leptonic model. This is because in such a model the luminosity ratio of the External-Compton and synchrotron components is tightly related to the frequency ratio of these components, and in this particular case an unrealistically high energy density of the external radiation would be implied. Therefore, we consider a well-constrained two-zone blazar model to interpret the entire dataset. In this framework, the observed infrared emission is associated with the synchrotron component produced in the hot-dust region at the supra-pc scale, while the gamma-ray emission is associated with the External-Compton component produced in the broad-line region at the sub-pc scale. In addition, the optical/UV emission is associated with the accretion disk thermal emission, with the accretion disk corona likely contributing to the X-ray emission.Comment: 13 pages, 8 figures, 7 tables; accepted for publication in the Astrophysical Journa

Middlesex/punctata Event in the Rhenish Basin (Padberg section, Sauerland, Germany) – Geochemical clues to the early-middle Frasnian perturbation of global carbon cycle

A positive carbon stable isotope excursion of about 3‰is documented in the topmost lower Frasnian at Padberg, eastern Rhenish Massif, as a muted record of the worldwide early−middle Frasnian isotopic perturbation (punctata Event; up to 6–8‰ shift in both δ13Ccarb and δ13Corg elsewhere), comparable with the Appalachian δ13C curve. This German isotopic signature occurs in a 12 m thick calciturbidite succession and correlates well with the three-step chemostratigraphic pattern known from the Holy Cross Mountains, Poland. It is especially clear in the δ13Corg shifts, whilst δ13Ccarb (and elemental geochemical) proxies are partly biased by post-sedimentary alterations. The New York State, Polish, Nevada and Padberg conodont successions place the onset of the major positive δ13C excursion slightly beneath the early–middle Frasnian boundary, with Ancyrodella nodosa (previously Ad. gigas form 1) as the main conodont guide species, and coincident with the Middlesex transgression and spread of cold, nutrient-rich, poorly oxygenated water masses. In the light of geochemical proxies, enhanced primary production and oxygen deficiency occurred evidently in the Rhenish Basin during the punctata Event. Moderate Hg enrichments in the early Middlesex/punctata Event interval suggest a volcanic signature. However, conclusive data from other regions are required to differentiate between effects of the regionally wellknown synsedimenary magmatism and of a possible global volcanic trigger for the biogeochemical perturbation

Baltic provenance of top-Famennian siliciclastic material of the northern Rhenish Massif, Rhenohercynian zone of the Variscan orogen

The provenance of top-Famennian sedimentary rocks linked to the Hangenberg Crisis from the northern Rhenish Massif (Germany) was investigated by the means of detrital zircon U-Pb geochronology. Based on the obtained age spectra, three main tectonothermal domains are recognized as possible sources: Paleo- and Mesoproterozoic (~ 2000–1000 Ma) units of Baltica and Early Paleozoic Caledonian orogen (~ 500–400 Ma). Our interpretation of the detritus having been derived from northern source areas, i.e., Baltica and the Scandinavian Caledonides, with a minor input of German-Polish (Rügen-Pomeranian) Caledonides, contradicts the traditional view that, during the Upper Devonian, the northern Rhenish Massif was supplied by detritus from the south. Complementary mineralogical, textural and geochemical analyses point to a derivation of the detritus of Drewer and Hangenberg Sandstones mainly from felsic, recycled continental crust. The elevated concentrations of Pb and Zn in the studied sections are a feature attributed to hydrothermal alteration related to the terminal Devonian synsedimentary volcanism or post-depositional Variscan deformation

Reply to Comment by M.F. Pereira, J.B. Silva and C. Gama on "Baltic provenance of top-Famennian siliciclastic material of the northern Rhenish Massif, Rhenohercynian zone of the Variscan orogen, by Koltonik et al., International Journal of Earth Sciences (2018) 107:2645–2669"

The authors of the Comment suggest that our geological overview map of the European Variscides is incorrect in the section showing SW Iberia (our Fig. 1a). However, our paper reports results of the provenance study from the northern Rhenish Massif, and does not attempt to discuss the architecture and tectonic evolution of the Appalachian-Variscan belt. The aim of Fig. 1 is to locate the study area in the geological context of the European Variscides and not to extrapolate the implications of our findings down to southern Portugal. The map is mostly based on Franke (2014) that is explicitly stated in the caption. Our results are neutral towards the hypothetical correlation between the Mid-German Crystalline High and the southern domains of the Ossa-Morena Zone that is shown on the map[…

Validating post-AGB candidates in the LMC and SMC using SALT spectra

We selected a sample of post-AGB candidates in the Magellanic Clouds on the basis of their near- and mid-infrared colour characteristics. Fifteen of the most optically bright post-AGB candidates were observed with the South African Large Telescope in order to determine their stellar parameters and thus to validate or discriminate their nature as post-AGB objects in the Magellanic Clouds. The spectral types of absorption-line objects were estimated according to the MK classification, and effective temperatures were obtained by means of stellar atmosphere modelling. Emission-line objects were classified on the basis of the fluxes of the emission lines and the presence of the continuum. Out of 15 observed objects, only 4 appear to be genuine post-AGB stars (27\%). In the SMC, 1 out of 4 is post-AGB, and in the LMC, 3 out 11 are post-AGB objects. Thus, we can conclude that the selected region in the colour-colour diagram, while selecting the genuine post-AGB objects, overlaps severely with other types of objects, in particular young stellar objects and planetary nebulae. Additional classification criteria are required to distinguish between post-AGB stars and other types of objects. In particular, photometry at far-IR wavelengths would greatly assist in distinguishing young stellar objects from evolved ones. On the other hand, we showed that the low-resolution optical spectra appear to be sufficient to determine whether the candidates are post-AGB objects.Comment: 19 pages, 19 figures, A&A in pres

Obesity as a risk factor of in-hospital outcomes in patients with endometrial cancer treated with laparoscopic surgical mode

Objectives: Obesity has been suggested to have a negative influence on procedural outcomes of endometrial cancer laparoscopic treatment. Obesity and other possible risk factors of laparoscopic endometrial cancer treatment has not been precisely described in the literature. The aim of the study is to determine the factors that have the greatest influence on the course of laparoscopic surgery for endometrial cancer, with particular emphasis on the influence of obesity. Material and methods: The study included 75 females who were treated for endometrial cancer by laparoscopic surgery. Preoperative body-mass index (BMI), waist circumference(WC), waist to hip ratio(WHR), and selected anatomical indices were measured. The duration of surgery and hospitalization stay, loss of hemoglobin, and procedural-related complications served as parameters of in-hospital outcomes. Results: Multiple linear regression analysis indicate the body mass as most sensitive parameter of obesity which influence in-hospital outcomes in patients treated with laparoscopic procedure. Procedural-related complications occurred in the group of patients with significantly greater WC and BMI. Multiple linear regression indicates also histological grading (G1–G3), external conjugate, intertrochanteric distance as significant risk factors. The multiple linear regression analysis confirmed also that implementation of sentinel lymph node procedure is related with decreased hemoglobin loss in patients with cancer of endometrium compare to lymphadenectomy without sentinel node biopsy(Est.: 0.488; 95% CI: 0.083–0.892, p = 0.018). Conclusions: The most sensitive risk factor of in-hospital outcomes in laparoscopic treatment of endometrial cancer is body mass. The implementation of the sentinel node procedure is associated with reduced surgery time and reduced hemoglobin loss

Periprocedural decrease in tumor necrosis factor alpha is a risk factor for atrial fibrillation recurrence after ablation

Background: Concentration of tumor necrosis factor alpha (TNF-alpha) might be useful in selecting patients with paroxysmal atrial fibrillation (PAF) who will benefit the most from pulmonary vein isolation. Material and methods: This is a prospective cohort study among patients with PAF who had sinus rhythm prior to undergoing either radiofrequency ablation or cryoablation procedure. Blood samples were collected at the start of the procedure and 16-24 h after. TNF-alpha concentrations were measured. Follow-up data was obtained during a structured telephone interview and 24-hour ECG Holter monitoring 12 months after the ablation procedure. Results: Thirty seven patients were enrolled. After 12-month follow-up 27 patients maintained sinus rhythm, 8 had recurrence of AF and 2 were lost to follow-up. There was no significant correlation between TNF-alpha concentrations in any of the samples and the recurrence of arrhythmia (for pre-procedural samples: 1.75 pg/ ml vs. 1.74 pg/ml; p = 0.72; for post-procedural samples: 1.49 pg/ml vs. 1.79 pg/ml; p = 0.16). In patients who had a recurrence of AF, we observed a decrease in the periprocedural TNF-alpha concentration (-0.12 pg/ml vs 0.05 pg/ml; p = 0.05). Conclusions: Neither pre- nor post-procedural TNF-alpha concentrations are predictive of ablation outcome in patients with PAF. We observed a decrease in the periprocedural TNF-alpha concentration in patients who had AF recurrence