(Table 1) Neutral and phenolic organohalogen compounds in blubber samples of ringed seals (Pusa hispida) from East Greenland

We report on the comparative bioaccumulation, biotransformation and/or biomagnification from East Greenland ringed seal (Pusa hispida) blubber to polar bear (Ursus maritimus) tissues (adipose, liver and brain) of various classes and congeners of persistent chlorinated and brominated contaminants and metabolic by-products: polychlorinated biphenyls (PCBs), chlordanes (CHLs), hydroxyl (OH-) and methylsulfonyl (MeSO2-) PCBs, polybrominated biphenyls (PBBs), OH-PBBs, polybrominated diphenyl ether (PBDE) and hexabromocyclododecane (HBCD) flame retardants and OH- and methoxyl (MeO-) PBDEs, 2,2-dichloro-bis(4-chlorophenyl)ethene (p,p'-DDE), 3-MeSO2-p,p'-DDE, pentachlorophenol (PCP) and 4-OH-heptachlorostyrene (4-OH-HpCS). We detected all of the investigated contaminants in ringed seal blubber with high frequency, the main diet of East Greenland bears, with the exception of OH-PCBs and 4-OH-HpCS, which indicated that these phenolic contaminants were likely of metabolic origin and formed in the bears from accumulated PCBs and octachlorostyrene (OCS), respectively, rather than being bioaccumulated from a seal blubber diet. For all of the detectable sum of classes or individual organohalogens, in general, the ringed seal to polar bear mean BMFs for SumPCBs, p,p'-DDE, SumCHLs, SumMeSO2-PCBs, 3-MeSO2-p,p'-DDE, PCP, SumPBDEs, total-(alpha)-HBCD, SumOH-PBDEs, SumMeO-PBDEs and SumOH-PBBs indicated that these organohalogens bioaccumulate, and in some cases there was tissue-specific biomagnification, e.g., BMFs for bear adipose and liver ranged from 2 to 570. The blood-brain barrier appeared to be effective in minimizing brain accumulation as BMFs were <= 1 in the brain, with the exception of SumOH-PBBs (mean BMF = 93±54). Unlike OH-PCB metabolites, OH-PBDEs in the bear tissues appeared to be mainly accumulated from the seal blubber rather than being metabolic formed from PBDEs in the bears. In vitro PBDE depletion assays using polar bear hepatic microsomes, wherein the rate of oxidative metabolism of PBDE congeners was very slow, supported the probability that accumulation from seals is the main source of OH-PBDEs in the bear tissues. Our findings demonstrated from ringed seal to polar bears that organohalogen biotransformation, bioaccumulation and/or biomagnification varied widely and depended on the contaminant in question. Our results show the increasing complexity of bioaccumulated and in some cases biomagnified, chlorinated and brominated contaminants and/or metabolites from the diet may be a contributing stress factor in the health of East Greenland polar bears.

(Table 1) Concentrations of the main organochlorine pesticides in liver and plasma samples of ringed seals (Phoca hispida)

The present study investigates the concentrations and patterns of organochlorine pesticides (OCPs) and their metabolites in liver and plasma of two ringed seal populations (Phoca hispida): lower contaminated Svalbard population and more contaminated Baltic Sea population. Among OCPs, p,p'-DDE and sum-chlordanes were the highest in concentration. With increasing hepatic contaminant concentrations and activities of xenobiotic-metabolizing enzymes, the concentrations of 3-methylsulfonyl-p,p'-DDE and the concentration ratios of pentachlorophenol/hexachlorobenzene increased, and the toxaphene pattern shifted more towards persistent Parlar-26 and -50 and less towards more biodegradable Parlar-44. Relative concentrations of the chlordane metabolites, oxychlordane and -heptachlorepoxide, to sum-chlordanes were higher in the seals from Svalbard compared to the seals from the Baltic, while the trend was opposite for cis- and trans-nonachlor. The observed differences in the OCP patterns in the seals from the two populations are probably related to the catalytic activity of xenobiotic-metabolizing enzymes, and also to differences in dietary exposure.

Concentrations of brominated and chlorinated contaminants in adipose tissue of polar bears (Ursus maritimus) between 1991-2007

Adipose tissue was sampled from the western Hudson Bay (WHB) subpopulation of polar bears at intervals from 1991 to 2007 to examine temporal trends of PCB and OCP levels both on an individual and sum-contaminant basis. We also determined levels and temporal trends of emerging polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), polybrominated biphenyls (PBBs) and other current-use brominated flame retardants. Over the 17-year period, sum DDT (and p,p'-DDE, p,p'-DDD, p,p'-DDT) decreased (-8.4%/year); alpha-hexachlorocyclohexane (alpha-HCH) decreased (-11%/year); beta-HCH increased ( + 8.3%/year); and sum PCB and sum chlordane (CHL), both contaminants at highest concentrations in all years (>1 ppm), showed no distinct trends even when compared to previous data for this subpopulation dating back to 1968. Some of the less persistent PCB congeners decreased significantly (-1.6%/year to -6.3%/year), whereas CB153 levels tended to increase (+ 3.3%/year). Parent CHLs (c-nonachlor, t-nonachlor) declined, whereas non-monotonic trends were detected for metabolites (heptachlor epoxide, oxychlordane). sum chlorobenzene, octachlorostyrene, sum mirex, sum MeSO2-PCB and dieldrin did not significantly change. Increasing sum PBDE levels (+13%/year) matched increases in the four consistently detected congeners, BDE47, BDE99, BDE100 and BDE153. Although no trend was observed, total-(alpha)-HBCD was only detected post-2000. Levels of the highest concentration brominated contaminant, BB153, showed no temporal change. As long-term ecosystem changes affecting contaminant levels may also affect contaminant patterns, we examined the influence of year (i.e., aging or "weathering" of the contaminant pattern), dietary tracers (carbon stable isotope ratios, fatty acid patterns) and biological (age/sex) group on congener/metabolite profiles. Patterns of PCBs, CHLs and PBDEs were correlated with dietary tracers and biological group, but only PCB and CHL patterns were correlated with year. DDT patterns were not associated with any explanatory variables, possibly related to local DDT sources. Contaminant pattern trends may be useful in distinguishing the possible role of ecological/diet changes on contaminant burdens from expected dynamics due to atmospheric sources and weathering.

Crystal Chemistry of the Noncentrosymmetric Eulytites: A(3)Bi(XO4)(3) (X = V, A = Pb; X = P, A = Ca, Cd, Sr, Pb)

Eulytite compounds, A(3)Bi(XO4)(3) (X = P, A = Ca, Cd, Sr, Pb), belong to the noncentrosymmetric space group l (4) over bar 3d (No. 220) as determined by single-crystal X-ray diffraction studies. The crystals were grown from the melt-cool technique with considerable difficulty as the compounds melt incongruently at their melting temperature, except for the compound Pb3Bi(PO4)(3). The unit cell parameter a is 9.984(5), 9.8611(3), 10.2035(3), and 10.3722(2) angstrom for Ca3Bi(PO4)(3), Cd3Bi(PO4)(3), Sr3Bi(PO4)(3), and Pb3Bi(PO4)(3) respectively, and there are four formula units in the unit cell. The structure of Pb3Bi(VO4)(3), a unique eulytite with vanadium substitution, is compared with all these phosphorus substituted eulytites. The A(2+) and Bi3+ cations occupy the special position (16c) while the O anions occupy the general Wyckoff position (48e) in the crystal structure. Only one O position has been identified for Pb3Bi(PO4)(3) and Pb3Bi(VO4)(3), whereas two O atom sites were identified for Ca3Bi(PO4)(3), Cd3Bi(PO4)(3), and Sr3Bi(PO4)(3). The UV-vis diffuse reflectance spectra indicate large band gaps for all the phosphate eulytites while a lower band gap is observed for the vanadate eulytite. The feasibility of the use of these compounds in optoelectronic devices has been tested by measuring the second-harmonic generation (SHG) values which have been found to be of a magnitude equivalent to the commercially used KDP (KH2PO4).

Spin-orbit effects on photoionization-produced alignment of the Ar+ 3p(4)(P-3)4p levels

We have determined photoionization spectra of Ar with excitation of the 3p(4)(P-3)4p states emphasizing the effects of two different classes of Ar+ spin-orbit interactions. The spin-orbit splitting of each Ar+ state adequately describes the resonant excitation of the quartet states of Ar+, and gives Ar photoionization cross sections with excitation of the 3p4(3P)4p P-2(3/2)o and P-4(5/2)o levels of Ar+ in sufficiently good agreement with experiment to identify the observed resonances and to estimate the excitation strengths. In addition, we demonstrate the importance of spin-orbit induced mixing of different Ar+ LS-coupled states for observables such as the alignment of the 3p(4)(P-3)4p P-4(5/2)o level and the excitation of Rydberg series converging to the 3p(4)(P-3)4p S-2(o) and S-4(o) thresholds.

Indirect Study of the (2)H(d,p)(3)H and (2)H(d,n)(3)He Reactions at Astrophysical Energies via the Trojan Horse Method

The (2)H(d,p)(3)H and (2)H(d,n)(3)He reactions have been indirectly studied by means of the Trojan Horse Method applied to the quasi-free (2)H((3)He, p(3)H)(1)H (2)H((3)He, n(3)He)(1)H reaction at 18 MeV of beam energy. This is the first experiment where the spectator (here (1)H) has been detected in coincidence with the charged participant, avoiding the limitations of standard neutron detectors. The d - d relative energy has been measured from 1.5 MeV down to 2 keV, at center of mass angles from 40A degrees to 170A degrees. Indirect angular distributions are compared with the direct behaviour in the overlapping regions.

Structure and Bonding in Stannadiphospholes and their Dianions SnC(2)P(2)R(2)(m) (R=H, tBu m=0,-2): A Comparative Study with C(5)H(5)(+) and C(5)H(5)(-) Analogues

The potential energy surfaces of both neutral and dianionic SnC(2)P(2)R(2) (R=H, tBu) ring systems have been explored at the B3PW91/LANL2DZ (Sn) and 6-311 + G* (other atoms) level. In the neutral isomers the global minimum is a nido structure in which a 1,2-diphosphocyclobutadiene ring (1,2-DPCB) is capped by the Sn. Interestingly, the structure established by Xray diffraction analysis, for R=tBu, is a 1,3-DPCB ring capped by Sn and it is 2.4 kcal mol(-1) higher in energy than the 1,2-DPCB ring isomer. This is possibly related to the kinetic stability of the 1,3-DPCB ring, which might originate from the synthetic precursor ZrCp(2)tBu(2)C(2)P(2). In the case of the dianionic isomers we observe only a 6 pi-electron aromatic structure as the global minimum, similarly to the cases of our previously reported results with other types of heterodiphospholes.([1,4,19]) The existence of large numbers of cluster-type isomers in neutral and 6 pi-planar structures in the dianions SnC(2)P(2)R(2)(2-) (R=H, tBu) is due to 3D aromaticity in neutral clusters and to 2D pi aromaticity of the dianionic rings. Relative energies of positional isomers mainly depend on: 1) the valency and coordination number of the Sn centre, 2) individual bond strengths, and 3) the steric effect of tBu groups. A comparison of neutral stannadiphospholes with other structurally related C(5)H(5)(+) analogues indicates that Sn might be a better isolobal analogue to P(+) than to BH or CH(+). The variation in global minima in these C(5)H(5)(+) analogues is due to characteristic features such as 1) the different valencies of C, B, P and Sn, 2) the electron deficiency of B, 3) weaker p pi-p pi bonding by P and Sn atoms, and 4) the tendency of electropositive elements to donate electrons to nido clusters. Unlike the C5H5+ systems, all C(5)H(5)(-) analogues have 6 pi-planar aromatic structures as global minima. The differences in the relative ordering of the positional isomers and ligating properties are significant and depend on 1) the nature of the pi orbitals involved, and 2) effective overlap of orbitals.

Stable p-type conductivity in B and N co-doped ZnO epitaxial thin film

We report on the observation of stable p-type conductivity in B and N co-doped epitaxial ZnO thin films grown by pulsed laser deposition. Films grown at higher oxygen partial pressure (similar to 10(-1) Torr) shows p-type conductivity with a carrier concentration of similar to 3 x 10(16) cm(-3). This p-type conductivity is associated with the significant decrease in defect emission peaks due to the vacancy oxygen (V-O) and Schottky type-I native defects compared to films grown at low oxygen partial pressure (similar to 10(-5) Torr). The p-type conductivity is explained with the help of density functional theory (DFT) calculation considering off-stoichiometric BN1+x in the ZnO lattice. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Influence of composition on the structure and properties of Fe-Pd-P and Ni-Pd-P amorphous alloys

Ternary alloys of nickel-palladium-phosphorus and iron-palladium- phosphorus containing 20 atomic % phosphorus were rapidly quenched from the liquid state. The structure of the quenched alloys was investigated by X-ray diffraction. Broad maxima in the diffraction patterns, indicative of a glass-like structure, were obtained for 13 to 73 atomic % nickel and 13 to 44 atomic % iron, with palladium adding up to 80%.

Radial distribution functions were computed from the diffraction data and yielded average interatomic distances and coordination numbers. The structure of the amorphous alloys could be explained in terms of structural units analogous to those existing in the crystalline Pd₃P, Ni₃P and Fe₃P phases, with iron or nickel substituting for palladium. A linear relationship between interatomic distances and composition, similar to Vegard's law, was shown for these metallic glasses.

Electrical resistivity measurements showed that the quenched alloys were metallic. Measurements were performed from liquid helium temperatures (4.2°K) up to the vicinity of the melting points (900°K- 1000°K). The temperature coefficient in the glassy state was very low, of the order of 10^-4/°K. A resistivity minimum was found at low temperature, varying between 9°K and 14°K for Ni_x-Pd_80-x -P₂₀ and between 17°K and 96°K for Fe_x-Pd_80-x -P₂₀, indicating the presence of a Kondo effect. Resistivity measurements, with a constant heating rate of about 1.5°C/min,showed progressive crystallization above approximately 600°K.

The magnetic moments of the amorphous Fe-Pd-P alloys were measured as a function of magnetic field and temperature. True ferromagnetism was found for the alloys Fe₃₂-Pd₄₈-P₂₀ and Fe₄₄-Pd₃₆-P₂₀ with Curie points at 165° K and 380° K respectively. Extrapolated values of the saturation magnetic moments to 0° K were 1.70 µ_B and 2.10 µ_B respectively. The amorphous alloy Fe₂₃-Pd₅₇-P₂₀ was assumed to be superparamagnetic. The experimental data indicate that phosphorus contributes to the decrease of moments by electron transfer, whereas palladium atoms probably have a small magnetic moment. A preliminary investigation of the Ni-Pd-P amorphous alloys showed that these alloys are weakly paramagnetic.

植物N;P计量化学：中国高等之外的分异规律与野外试验初步验证

元素化学计量学指从化学计量学的角度出发，通过分析比较生命物质不同结构层次（分子、细胞、器官、机体、种群、群落等）或生态系统中元素的相对比值，来研究各层次相互之间以及生态学过程中元素之间的关系。生态化学计量学研究可以把生态实体的各个层次存元素水平上统一起来，足近年来新兴的一个生态学研究领域，广泛应用于生态学研究中。C，N，P是生物地球化学循环中的重要元素，在生态系统中占有重要地位，许多环境问题都与它们有关，由此这三种元素的化学计量学受到生态学家们的普遍关注。C:N:P化学计量学在水生生态系统中研究较为深入，目前已发展到染色体水平，而在陆地生态系统中的研究较为匮乏近年来由于人类活动的强烈影响，这三种元素的循环在速度和规模上都发生了前所未有的改变，导致一系列环境问题的出现，因此C：N:P化学计量学在陆地生态系统中的研究就显得尤为重要。作为地球生命存在基础的绿色植物，在地球上已有数亿年的演化历史，研究陆地植物的元素化学计量学不仅有助于深入了解植物存在于地球上的内在机制，而且可以为许多环境问题的解决提供理论依据。本文首先建立中国不同地区植物氮磷含量数据库，通过数据分析找出一般规律，并进一步揭示植物不同进化阶段N:P化学计量比的变化规律。在此基础上，通过在内蒙古羊草草原设立不同施肥样地来模拟自然界不同氮磷环境，从试验水平上研究不同施肥处理及施肥梯度下生态系统中氮、磷、有机质的变化规律，并从化学计量学角度研究其内在机制。 利州新建成的中国维管植物数据库（包含1603种植物）研究了不同进化水平以及不同功能群（生活型）间植物N:P比的变化规律，并沿胡焕庸线（胡线）把中团分为为东西两部分，从总体水平上对比了东、西部间叫植物氮磷含量以及N：P的异同。结果表明：l）从演化水平来看，尽管氮磷含量表现出极大的差异，除豆科植物外，植物N：P基本保持稳定水平;2）木本植物与草本植物的N：P比差异．显著，木本植物之间（常绿乔木，常绿灌木，落叶乔木，落叶灌木）N：P不具有显著差异;3）中国东西部植物养分含量和N：P比表现出极显著差异，东部的养分含量低于西部，而N:P显著高于西部。 在内蒙古羊草草原两块永久实验样地（样地A：1980年围封样地和样地B：1999年田封样地）进行了为期两年的N素和P素添加试验。氮素添加梯度为0，5，15，30，50，80 g NHN03.m.2.yr-1。P素添加梯度为0，2，4，8，16，and 32 g P2Osm-2 yr-1（仪分析了羊草器官的结果）。分别从植物器官、物种、功能群水平研究了N素添加对N:P化学计量学的影响，此外还研究了土壤和凋落物C：N:P化学计量学对N素添加的响应。结合生物量的变化趋势，探讨了元素化学计量学对养分状况的指示作用。 1．羊草器官对施肥的响应结果表明，添加N素可以显著提高羊草器官中的含N量，p素可以显著提高器官中的含P量：除2001年样地A中的根茎外，根茎中的含P量基本不受N素添加的影响;茎中的含P量同样表现出不受N素添加影响的趋势（2000年B区茎除外）：N素添加可以显著增大羊草叶片中的含P量(B区2000年叶片除外)。P素添加对羊草器官的含N量没有影响;羊草器官中的氮磷含量施肥处理下表现出显著的正相关关系（N素添加下B区叶片除外）。N素添加对羊草器官的N:P比没有显著影响（A区茎2000年和B区叶片2000年除外）：P素添加显著降低了羊草器官中的N:P比。 2．四种优势植物（羊草、羽茅、针茅和苔草）地上生物量和N:P化学计量学对氮肥的响应研究发现，四个物种的氮磷含量均具有极显著相关关系;氮肥可以显著提高样地A中的羽茅生物量，降低苔草的生物量，而使样地B中的羊草生物量增大;两块样地中，四个物种的氮磷含量及N：P比均随N素水平的增高而增大（样地A中的羽茅N:P比除外）。 3．基于生活型划分的功能群（多年生根茎禾草，多年生丛生禾草，豆科植物，多年生杂类草，一二年生植物，灌木和半灌木）对N素添加的响应研究表明：施N可以提高样地A中的多年生丛生禾草的生物量，而使样地B中的多年生根苇禾草增加;多年生杂类草的相对多度在两个样地中均随施氨水平的增加而显著 降低：在样地B中，施氮可以显著提高不同功能群的氮磷含量;在样地A中，功能群N、P含量对施肥的响应并没有一致的变化规律，添加N素可以显著提高不同功能群的含N量（豆科植物除外），多年生根茎禾草和多年生杂类草的P含量有显著增大的趋势（P < 0.005），而其它功能群（豆科植物、灌木和小半灌木、多年生杂类草和～二年生杂类草）的P含量基本恒定（P>0.05）;在样地A中，多年生丛生禾草，多年生杂类草，一二年生植物，灌木和半灌木的N：P比随施氨水平的增加而显著增大，多年生根茎禾草和豆科植物的N:P比基本不变;在样地B中，多年生丛生禾草的N:P比随施氨水平的增加而显著增大，多年生根茎禾草、多年生杂类草和…二年生杂类草不受施氨水平的影响。 4．添加N素对根实验结果表明：两块样地中，上层根(0-10 cm)的生物量仅在施N后第一年显著增加，而下层根(10-20 cm)的地下生物量在两年的施N处理下均不受施肥梯度的影响i在样地A中，施肥后第一年对根的N、P含量影响不显著，施肥后第二年可以显著增大上层根的N、P含量;在样地B中，添加N素后第一年可以显著增大根的含P量; 在两个样地中，两年的N肥处理对根的N：P比没有显著影响：在施氨处理中，根的N、P含量及N:P比在施肥第一年的响应要高于第二年。 5．所有处理中，上层土壤(O-lO cm)养分含量（有机碳，全氮，全磷）均高于下层土壤（10-20 cm）;在样地A中，氮素添加对r十壤有机碳没有显著性作用，在施肥第一年可以显著增加上层土壤的N、P含量，而在施肥后第二年对土壤N、P含量没有显著影响;在样地B中，添加N素对两年的土壤养分均没有显著影响：养分添加两个样地土壤中的元素比值（C:N比，C:P比，N:P比）没有显著影响;土壤养分对施N一年后的响应要高于第二年。 6．养分添加对凋落物化学特征及化学计量学特征的影响研究结果表明：凋落物现存量不受施肥的影响;2001年凋落物现存量与2000年和2001年的地上生物量相关关系不显著;添加N素可以显著提高凋落物的N含量，而对有机碳含量和P含量没有显著影响;凋落物C：N比随施肥梯度的增大而显著降低，N:P比显著增高，而C:P比没有明显变化。 以上研究结果表明，不同植物功能群的N:P比存在差异，人类活动强烈影响自然植被中的植物N：P比;但植物的N：P比不受植物进化的影响（豆科植物除外）;由于植物已有数亿年的演化历史，同时N与P在植物的结构和功能上具有密切的联系，在生物地球化学循环中办存在耦合作用。因此植物N：P比值恒定可能是一普适性规律。 N素添加试验表明，在植物根、地上器官、物种和功能群水平上N与P均呈显著正相关关系，反映了植物体内的氮磷含量具有协同作用。共存种对N肥的响应不同，表明物种受不同元素的制约。因此除非把生态系统中所有物种对施肥的响应刻画清楚，笼统的认定生态系统缺乏某种元素是不适当的。 施肥试验表明，两种围封时间样地的主要限制性元素不同。极度退化(样地B)植物生长主要缺N，而在保护较好样地(样地A)，P也逐步成为一种限制因素。反映了随着保护时间的增加，植物生长逐渐由N限制型向N、P共同限制型过渡。添加的养分要么被植物吸收，挥发到大气中，或以凋落物的形式返还到土壤表层。但是对养分的预算有待于进一步研究。土壤中的养分含量对N素添加有…个滞后效应，而植物响应较为迅速。功能群N:P比在施肥实验中不能保持恒定，可能是由于实验时间较短的缘故;化学计量学的研究表明羊草草原分解凋落物的微生物受P素的制约，可能是由于植物体内具有高的P素再转运机制。这一结论有待于进一步的验证。氮肥降低了凋落物的C:N比，因此凋落物的分解速率可能将要发生改变。这需要进一步开展C循环的研究。

潮棕壤不同利用方式pH和Olsen-P的垂直变化特征

对潮棕壤4种土地利用方式经过14年后土壤pH和Olsen-P在0～150cm土体10个土层中的垂直分布情况进行的比较研究表明,不同利用方式下土壤pH和Olsen-P含量的剖面分布差异显著,说明不同利用方式对土壤pH和Olsen-P有较大影响。林地和撂荒地0～5cm土层pH分别为>7.0和6.5～7.0,玉米地0～20cm各土层土壤pH基本为6.0以下;20cm以下各土层中的pH,水稻田土壤呈微碱性,玉米地和撂荒地接近中性,林地呈微酸性。土体中Olsen-P平均含量为撂荒地>林地>水稻田>玉米地。水稻田和玉米地0～20cm的3个土层Olsen-P含量明显高于20～80cm的4个土层,表明耕地土壤由于施P肥而导致的P素表聚性;林地和撂荒地0～5cm土层的Olsen-P含量大大高于5～80cm的6个土层,这可能与林地和撂荒地的P素生物归还及基本不受人为扰动有关。4种土地利用方式下土壤各层次Olsen-P含量垂直分布的散点折线图呈现出较为相似的特征。80cm以下的3个土层Olsen-P含量接近或超过表层土壤,主要是受母质层相对较高的全P含量影响所致,也可能与地下水作用有关,不过具体原因还有待于进一步研究。