Swedish University of Agricultural Sciences

About: Swedish University of Agricultural Sciences is a education organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Population & Soil water. The organization has 13510 authors who have published 35241 publications receiving 1414458 citations. The organization is also known as: Sveriges Lantbruksuniversitet & SLU.

Hydrated metal ions in aqueous solution: How regular are their structures?

Abstract: The hydration reaction is defined as the transfer of an ion or neutral chemical species from the gaseous phase into water, M n+ (g) → M n+ (aq). In this process, water mole- cules bind to metal ions through ion-dipole bonds of mainly electrostatic character. The hy- dration reaction is always strongly exothermic with increa sing heat of hydration with in- creasing charge density of the ion. The structures of the hydrated metal ions in aqueous solution display a variety of configurations depending on the size and electronic properties of the metal ion. The basic configurations of hydrated metal ions in aqueous solution are tetrahedral, octahedral, square antiprismatic, and tricapped trigonal prismatic. This paper gives an overview of the structures of hydrated metal ions in aqueous solution with special emphasis on those with a non-regular coordination figure. Metal ions without d-electrons in the valance shell form regular aqua complexes with a coordination figure, allowing a maxi- mum number of water molecules to be clustered around the metal ion. This number is de- pendent on the ratio of the metal ion radius to the atomic radius of oxygen in a coordinated water molecule (1.34 A). The lighter lanthanoid(III) ions have a regular tricapped trigonal prismatic configuration with the M-O distance to the capping water molecules somewhat longer than to the prismatic ones. However, with increasing atomic number of the lan- thanoid(III) ions, an increasing distortion of the capping water molecules is observed, result- ing in a partial loss of water molecules in the capping positions for the heaviest lanthanoids. Metal ions with d 4 and d 9 valance shell electron configuration, as chromium(II) and cop- per(II), respectively, have Jahn-Teller distorted aqua complexes. Metal ions with low charge and ability to form strong covalent bonds, as silver(I), mercury(II), palladium(II), and plat- inum(II), often display distorted coordination figures due to the second-order Jahn-Teller ef- fect. Metal ions with d 10 s 2 valence shell electron configuration may have a stereochemically active lone electron pair (hemi-directed complexes) or an inactive one (holo-directed). The hydrated tin(II), lead(II), and thallium(I) ions are hemi-directed in aqueous solution, while the hydrated bismuth(III) ion is holo-directed. The structures of the hydrated cationic oxo- metal ions are reported as well.

First Gene on the Avian W Chromosome (CHD) Provides a Tag for Universal Sexing of Non-Ratite Birds

Abstract: The avian W chromosome shares many features with the mammalian Y chromosome: it is small, mostly heterochromatic, and filled with large repetitive arrays. No gene so far been assigned to the W chromosome in any bird species and, as a practical consequence, a general tag for avian gender identification on the molecular level is lacking. Here I describe the isolation of a chicken homologue to the mouse chromo-helicase-DNA binding (CHD) gene which encodes a protein involved in global regulation of transcriptional activation on the chromatin level. The avian CHD gene exists in two genomic copies, one of which termed CHD-W) was located on the W chromosome in all non-ratio species investigated. The gene displays extreme levels of sequence conservation since chicken CHD-W and mouse CHD are 82.9% and 95.6% identical at the nucleotide and amino acid level respectively. Molecular sexing can be accomplished in probably all non-ratite birds by hybridizing Southern blots with CHD probes, PCR-based gender identification is also demonstrated. A general system for avian sexing should facilitate many studies of behaviour, evolutionary ecology, genetics, and evolution.

Sources of and processes controlling CO2 emissions change with the size of streams and rivers

Abstract: Carbon dioxide (CO2) evasion from streams and rivers to the atmosphere represents a substantial flux in the global carbon cycle(1-3). The proportions of CO2 emitted from streams and rivers that com ...

Genomics and the challenging translation into conservation practice

Abstract: The global loss of biodiversity continues at an alarming rate. Genomic approaches have been suggested as a promising tool for conservation practice as scaling up to genome-wide data can improve traditional conservation genetic inferences and provide qualitatively novel insights. However, the generation of genomic data and subsequent analyses and interpretations remain challenging and largely confined to academic research in ecology and evolution. This generates a gap between basic research and applicable solutions for conservation managers faced with multifaceted problems. Before the real-world conservation potential of genomic research can be realized, we suggest that current infrastructures need to be modified, methods must mature, analytical pipelines need to be developed, and successful case studies must be disseminated to practitioners.