Influence of the Leather Industry on the Pollution of Coastal Sediments by Chromium in the Zadar Area (Eastern Adriatic)

U radu je ispitan utjecaj dugogodišnjeg ispuštanja neobrađenih otpadnih voda Tvornice kože Zadar na raspodjelu kroma u sedimentu uvale Brodanov jaz (Zadar, srednji Jadran). Ispitivanja su provedena na četiri lokacije duž uvale (ušće P1, početak P2, sredina P3 i kraj uvale P4), a za usporedbu uzet je i uzorak sedimenta na onečišćenoj lokaciji 20 km sjevernije od uvale Brodanov jaz, u Ninu (R). Određivan je maseni udjel kroma u 3 granulometrijske klase sedimenta (A: 0,063-2,0 mm, B: 0,010-0,063 mm, C: < 0,010 mm). Maseni udjel Cr u sedimentu na ušću (P1) znatno je veći (6 puta) nego maseni udjel kroma u sedimentu na kraju uvale (P4). Na ušću (P1) i početku uvale (P2) maseni udjel kroma je u prosjeku 25 puta veći nego na referentnoj lokaciji u Ninu (R). Maseni udjel kroma u svim uzorcima obrnuto je proporcionalan promjeru čestica sedimenta, tako da sitnije klase sedimenta (C i B) imaju u prosjeku oko 4 puta više kroma nego najkrupnija klasa (A) istih uzoraka. Dobivena raspodjela čestica ukazuje na to da su povećane količine kroma u sedimentu uvale Brodanov jaz antropogenog izvora, tj. da potječu iz Tvornice kože Zadar.The influence of the long term discharge of untreated wastewaters from the leather factory in Zadar on the distribution of chromium in the bay of Brodanov Jaz has been investigated in this study. The investigation was performed at four locations along the bay (at the mouth - P1, the beginning - P2, the middle - P3 and the end - P4 of the bay). A sediment sample was also taken at an unpolluted location near the town of Nin, 20 km to the north of the Brodanov Jaz bay, for the purpose of comparison. The chromium concentration was determined in 3 granulometric competition of the sediment (A: 0.063-2.00 mm, B: 0.010-0,063 mm, C:<0.010 mm). The highest concentracion of chromium was observed in the sediment taken nearest to the wastewater outlet. The concentration of Cr in the sediment at the mouth (P1) was considerably higher (6 times) than at the end of the bay (P4). At the mouth (P1) and at the beginning of the bay (P2) Cr concentration was about 25 times higher than at the reference location in Nin. Concentrations of Cr in all samples were inversely proportional to grain size, so the finest fractions of sediment (C and B) contained about 4 times higher Cr concentrations than in the large grain fraction (A) of the same samples. The obtained distribution of Cr in the bay of Brodanov Jaz indicates that the increased Cr concentrations in sediment came from the leather industry, and that they are of anthropogenic origin

On the vibron dressing in the α\alpha--helicoidal macromolecular chains

We present a study of the physical properties of the vibrational excitation in $\alpha$--helicoidal macromolecular chains, caused by the interaction with acoustical and optical phonon modes. The influence of the temperature and the basic system parameters on the vibron dressing has been analyzed by employing the simple mean--field approach based on the variational extension of the Lang--Firsov unitary transformation. Applied approach predicts a region in system parameter space where one takes place an abrupt transition from partially dressed (light and mobile) to fully dressed (immobile) vibron states. We found that the boundary of this region depends on system temperature and type of bond among structural elements in the macromolecular chain.Comment: 22 pages, 12 figures, title changed, the interaction with optical phonon modes jointly with acoustical ones added, consideration significantly enlarged, references added, the paper develops the results of arxiv:1210.3918, accepted for publication in Chinese Physics

The subconvexity problem for \GL_{2}

Generalizing and unifying prior results, we solve the subconvexity problem for the $L$-functions of \GL_{1} and \GL_{2} automorphic representations over a fixed number field, uniformly in all aspects. A novel feature of the present method is the softness of our arguments; this is largely due to a consistent use of canonically normalized period relations, such as those supplied by the work of Waldspurger and Ichino--Ikeda.Comment: Almost final version to appear in Publ. Math IHES. References updated

Toward verification of the Riemann hypothesis: Application of the Li criterion

We substantially apply the Li criterion for the Riemann hypothesis to hold. Based upon a series representation for the sequence \{\lambda_k\}, which are certain logarithmic derivatives of the Riemann xi function evaluated at unity, we determine new bounds for relevant Riemann zeta function sums and the sequence itself. We find that the Riemann hypothesis holds if certain conjectured properties of a sequence \eta_j are valid. The constants \eta_j enter the Laurent expansion of the logarithmic derivative of the zeta function about s=1 and appear to have remarkable characteristics. {\em On our conjecture}, not only does the Riemann hypothesis follow, but an inequality governing the values \lambda_n and inequalities for the sums of reciprocal powers of the nontrivial zeros of the zeta function.Comment: to appear in Math. Physics, Analysis and Geometry; 1 figur

An electrochemical illustration of the mathematical modelling of chlorine impact and acidification in electrochemical tumour treatment and its application on an agar-agar gel system

Electrochemical treatment (EchT) of tumours, which is also known as electrochemical therapy, implies that tumour tissue is treated with a direct current through the use of electrodes. This was shown earlier when the major electrochemical reactions at the anode were chlorine and oxygen evolution and the impact of chlorine in EchT was investigated by mathematical modelling. In this work the electrochemical illustration of a mathematical model of electrochemical treatment of tumours is presented using a Pt electrode placed in agar-agar gel containing 1% phenolphthalein and NaCl. The appearance of the bright red color around the Pt wire due to the pH change caused by hydrogen evolution is used for the simulation of the shape and the boundaries of the tumour tissue. After the polarity was changed, oxygen evolution takes place on the Pt wire electrode and the red color disappears simulating the destructive influence of the electrochemical process on tumour tissue. A better understanding of the mathematical model presented earlier is achieved and it can be used for educational purposes in oncological praxis because agar-agar is the closest approximation to the ground substance of connective human tissue and successfully simulates the processes which occur in vivo. There is also some quantitative agreement between the results calculated earlier and those obtained in this work. The previous model was based on tissue, which was treated as an aqueous solution of sodium chloride containing bicarbonate and proteins and the results presented a detailed and useful quantitative analysis of the system. In this work, the quantitative analysis presented is based on an agar-agar system and the experimental conditions give the possibility of more detailed qualitative analysis. The combination of these two models offers a better simulation of the processes in vivo