Streetlights positively affect the presence of an invasive grass species.

Anthropogenic disturbances associated with urban ecosystems can create favorable conditions for populations of some invasive plant species. Light pollution is one of these disturbances, but how it affects the growth and establishment of invasive plant populations is unknown. Cheatgrass (Bromus tectorum) is a problematic invasive species where it has displaced native grassland communities in the United States, but to our knowledge, there have been no studies of the ecological factors that affect cheatgrass presence in urban ecosystems. We conducted field surveys in urban alleys in Denver, Colorado, to compare the presence of cheatgrass at sites with and without artificial light at night (hereafter artificial light) from streetlights. These streetlights are mounted on utility poles, which cause ground disturbance when installed in alleys; we were able to test the independent effect of poles on cheatgrass establishment because not all poles have streetlights on them. We found that cheatgrass was positively associated with the presence of streetlights and to a lesser extent poles. In addition to cheatgrass, we also found that other plants were positively associated with the presence of both poles and streetlights. Our results suggest that artificial light may benefit the occurrence of cheatgrass and other plant species in urban settings. While invasive populations of cheatgrass in wild habitats attract the most attention from managers, we suggest more consideration for this grass in urban environments where its growth and establishment benefit from anthropogenic changes.

Anomalous spin-orbit torques in magnetic single-layer films.

The spin Hall effect couples charge and spin transport1-3, enabling electrical control of magnetization4,5. A quintessential example of spin-Hall-related transport is the anomalous Hall effect (AHE)6, first observed in 1880, in which an electric current perpendicular to the magnetization in a magnetic film generates charge accumulation on the surfaces. Here, we report the observation of a counterpart of the AHE that we term the anomalous spin-orbit torque (ASOT), wherein an electric current parallel to the magnetization generates opposite spin-orbit torques on the surfaces of the magnetic film. We interpret the ASOT as being due to a spin-Hall-like current generated with an efficiency of 0.053 ± 0.003 in Ni80Fe20, comparable to the spin Hall angle of Pt7. Similar effects are also observed in other common ferromagnetic metals, including Co, Ni and Fe. First-principles calculations corroborate the order of magnitude of the measured values. This work suggests that a strong spin current with spin polarization transverse to the magnetization can be generated within a ferromagnet, despite spin dephasing8. The large magnitude of the ASOT should be taken into consideration when investigating spin-orbit torques in ferromagnetic/non-magnetic bilayers.

Management and effects of parenteral nutrition.

Despite nutrition being a basic human need, malnutrition in hospitals remains surprisingly common, with the effects clearly documented (Taylor and Goodison-McLaren, 1992). Malnourished patients are more likely to suffer from complications; are at increased risk of developing infections; have poor or delayed wound healing, increased mortality rates and longer hospital stays. This article focuses on the basics of parenteral nutrition in the adult, addressing a small selection of potential complications.

The pharmacological effects of novel nutrients on the immune system.

The role of novel nutrients that appear to have pharmacological effects on the immune system has been studied over the past 20 years. This area of research has been termed immunonutrition. This paper provides an overview of particular novel nutrients--argtnine, glutamine, omega-3 fatty acids, and nucleotides--and examines some of the evidence for the effects that they may have on immune function. The benefits to particular patient groups are also considered (Box 1).