The status of the world's land and marine mammals: diversity, threat, and knowledge

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.     

Antigen recognition by variable lymphocyte receptors

Variable lymphocyte receptors (VLRs) rather than antibodies play the primary role in recognition of antigens in the adaptive immune system of jawless vertebrates. Combinatorial assembly of leucine-rich repeat (LRR) gene segments achieves the required repertoire for antigen recognition. We have determined a crystal structure for a VLR-antigen complex, VLR RBC36 in complex with the H-antigen trisaccharide from human blood type O erythrocytes, at 1.67 angstrom resolution. RBC36 binds the H-trisaccharide on the concave surface of the LRR modules of the solenoid structure where three key hydrophilic residues, multiple van der Waals interactions, and the highly variable insert of the carboxyl-terminal LRR module determine antigen recognition and specificity. The concave surface assembled from the most highly variable regions of the LRRs, along with diversity in the sequence and length of the highly variable insert, can account for the recognition of diverse antigens by VLRs.     

Earth-Based Observations of the Galileo Probe Entry Site

Earth-based observations of Jupiter indicate that the Galileo probe probably entered Jupiter's atmosphere just inside a region that has less cloud cover and drier conditions than more than 99 percent of the rest of the planet. The visual appearance of the clouds at the site was generally dark at longer wavelengths. The tropospheric and stratospheric temperature fields have a strong longitudinal wave structure that is expected to manifest itself in the vertical temperature profile.     

Theoretical organometallic chemistry

Organometallic chemists have synthesized a remarkable variety of new structural types. In these structures ligands, which are organic or inorganic molecules of variable independent stability, bind to one or more transition metal atoms. An approach to an understanding of the electronic structure, geometrical preferences, and reactivity of these complexes may be made if the molecule is "decomposed" conceptually into a metal fragment, ML(n), and a ligand. A library of the molecular orbitals of these fragments is becoming available. One then "reconstructs" the molecule by examining the interaction of the orbitals of the ligand, typically an organic molecule, with the orbitals of the ML(n), fragment.     

Light-induced superconductivity in a stripe-ordered cuprate

One of the most intriguing features of some high-temperature cuprate superconductors is the interplay between one-dimensional "striped" spin order and charge order, and superconductivity. We used mid-infrared femtosecond pulses to transform one such stripe-ordered compound, nonsuperconducting La(1.675)Eu(0.2)Sr(0.125)CuO(4), into a transient three-dimensional superconductor. The emergence of coherent interlayer transport was evidenced by the prompt appearance of a Josephson plasma resonance in the c-axis optical properties. An upper limit for the time scale needed to form the superconducting phase is estimated to be 1 to 2 picoseconds, which is significantly faster than expected. This places stringent new constraints on our understanding of stripe order and its relation to superconductivity.     

Evaluation of oral fluids for surveillance of foodborne and zoonotic pathogens in pig farms

The use of oral fluid (OF) to detect zoonotic pathogens in pigs has been only scarcely assessed. We evaluated OF as a potential specimen for detection by culture of methicillin-resistant Staphylococcus aureus (MRSA) and Yersinia enterocolitica, and the detection of antibodies against Salmonella spp. and hepatitis E virus (HEV) using commercial ELISAs. Samples from 33 pig farms were collected at the beginning and end of the fattening period. Results of the OF samples were compared with the results of serum samples and nasal swabs from individual pigs and pen floor fecal samples, using the Cohen kappa (κ) and the McNemar test. For Salmonella spp. antibodies, OF samples were negative, although the corresponding serum samples were positive. The detection of HEV antibodies in sera and OF had agreement at the first sampling, and poor and significant agreement at the second sampling (κ = 0.185, McNemar p = 0.238; κ = 0.088, McNemar p < 0.001). At both sampling times, the detection of MRSA in nasal swabs and OF showed agreement (κ = 0.466, McNemar p = 0.077; κ = 0.603, McNemar p = 1); agreement was seen for the detection of Y. enterocolitica in fecal and OF samples (κ = 0.012, McNemar p = 0.868; κ = 0.082, McNemar p = 0.061, respectively). According to the McNemar test, the use of pen-based OFs is more feasible for the detection of MRSA and Y. enterocolitica by culture than is detection of antibodies by commercial ELISA.     

Response of Russet Burbank potatoes to soil fumigation and nitrogen fertilizers

Two field studies were conducted to determine the effects of soil fumigation on the response of Russet Burbank potatoes (Solanum tuberosum L.) to NH₄-N or NH₄NO₃ fertilizers. In one study fumigation increased yields but N source had no effect. In the other study fumigation had no effect but NH₄-N provided higher yields than NH₄NO₃. Microbial studies indicated that although populations of nitrifying bacteria were initially altered by fumigation, nitrification rates were similar to those in non-fumigated soil. In a controlled environment study in which potatoes were grown in fumigated field soil, neither N source nor fumigation had any effect on growth or yield. These studies indicated that fumigation had no effect on the response of potatoes to NH₄-N or NH₄NO₃ fertilizers.