Phosphorus nutrition of ectomycorrhizal and arbuscular mycorrhizal tree seedlings from a lowland tropical rain forest in Korup National Park, Cameroon

The relationship between mycorrhizal colonisation and phosphorus acquired by seedlings of the arbuscular mycorrhizal tree Oubanguia alata Bak f. (Scytopetalaceae) and the ectomycorrhizal tree Tetraberlinia moreliana Aubr. (Caesalpiniodeae) was evaluated at low and high inorganic phosphorus availability. AM colonisation was positively correlated with phosphorus uptake by O. alata at low, but not at high phosphorus availability. Seedlings growth was positively related to arbuscular mycorrhizal colonisation at both low and high phosphorus availability, suggesting that growth promotion by arbuscular mycorrhizas is not simply related to an increase of phosphorus uptake. In contrast, phosphorus uptake by T. moreliana was correlated with EM colonisation at both low and high phosphorus availability, but there was no relationship between growth and ectomycorrhizal colonisation. Promotion of phosphorus uptake by arbuscular mycorrhizas and ectomycorrhizas at low phosphorus availability is consistent with the co-occurrence of the two types of mycorrhiza in tropical rain forests where available soil phosphorus is low. However, ectomycorrhizal colonisation may also be of advantage where inputs of phosphorus rich litter raise the phosphorus status of the soil, as seen in the groves of ectomycorrhizal trees in Korup National Park, and may be one of the factors reinforcing local dominance by these trees

Shake & Bake: Dual-Use Chemicals, Contexts, and the Illegality of American White Phosphorus Attacks in Iraq

[Excerpt] “On November 29, 2005, in a Department of Defense press conference with Secretary of Defense Donald Rumsfeld and Gen. Peter Pace, Chairman of the Joint Chiefs of Staff, General Pace stated that white phosphorus “is a legitimate tool of the military,” and can be used for illumination, smoke, and incendiary purposes. Incredibly, the Department of Defense released an addendum to the press conference clarifying that white phosphorus was not used as an incendiary weapon. According to General Pace, “it was well within the law of war to use white phosphorus . . . for marking and screening.” This was the last official statement on white phosphorus. The chemical’s legality as an anti-personnel weapon within the laws of war or the Chemical Weapons Convention was not discussed. Despite the Pentagon’s claim that white phosphorus has only been used for legitimate purposes (illumination and smoke) in Iraq, there have been numerous allegations and accounts by members of the U.S. military, war correspondents, and Iraqi civilians that white phosphorus has been used as an anti-personnel weapon against Iraqi combatants and civilians within urban areas. This note examines: (1) “Shake & Bake”: the use of white phosphorus to flush out combatants from fortified positions so they can be killed with conventional munitions; (2) the direct use of white phosphorus illumination mortars against human targets; and (3) the use of improvised phosphorus bombs to clear insurgents out of buildings. White phosphorus is an example of a “dual-use” chemical. As with most dual-use chemicals, there are lawful and prohibited purposes. It is an especially legally precarious chemical because there are both legitimate and potentially improper military purposes. Peter Kaiser, spokesman for the Organization for the Prohibition of Chemical Weapons (OPCW) (the international body responsible for implementation of the Chemical Weapons Convention) has described the prohibited uses of white phosphorus as those military purposes that are dependent on the chemical’s toxicity. Thus, the central question of this article asks whether the legality of the United States’ intended use of anti-personnel white phosphorus depends on the chemical’s toxic properties. This note analyzes the legal implications of the cited examples of white phosphorus use by looking at the following: (1) general principles of international humanitarian law and the necessity defense, (2) the Zyklon B case, and (3) the Chemical Weapons Convention and the Chemical Weapons Convention Implementation Act of 1998.

Donor behavior in indium-alloyed silicon

The anomalous doping behavior of Si regrown from In solution was studied by (1) Schottky barrier evaluation of conductivity type, (2) electron microprobe analysis for phosphorus, and (3) channeling effect measurements for interstitial In. The latter showed In present at ~ 10^19 cm^–3, but not occupying a regular substitutional or interstitial position. A correlation was found in the first two measurements between phosphorus contamination and n-type conductivity. When the In was contacted only by quartz freshly etched in HF, the n-type behavior and phosphorus contamination disappeared. The anomalous doping behavior is most likely due to phosphorus inpurity picked up by the In

Multilayer black phosphorus as broadband saturable absorber for pulsed lasers from 1 to 2.7 {\mu}m wavelength

It attracts wide interest to seek universe saturable absorber covering wavelengths from near infrared to mid-infrared band. Multilayer black phosphorus, with variable direct bandgap (0.3-2 eV) depending on the layer number, becomes a good alternative as a universe saturable absorber for pulsed lasers. In this contribution, we first experimentally demonstrated broadband saturable absorption of multilayer black phosphorus from 1 {\mu}m to 2.7 {\mu}m wavelength. With the as-fabricated black phosphorus nanoflakes as saturable absorber, stable Q-switching operation of bulk lasers at 1.03 {\mu}m, 1.93 {\mu}m, 2.72 {\mu}m were realized, respectively. In contrast with large-bandgap semiconducting transition metal dichalcogenides, such as MoS2, MoSe2, multilayer black phosphorus shows particular advantage at the long wavelength regime thanks to its narrow direct bandgap. This work will open promising optoelectronic applications of black phosphorus in mid-infrared spectral region and further demonstrate that BP may fill the gap of between zero-bandgap graphene and large-bandgap TMDs

Effect of influent nutrient ratios and hydraulic retention time (HRT) on simultaneous phosphorus and nitrogen removal in a two-sludge sequencing batch reactor process

A laboratory-scale anaerobic–anoxic/nitrification sequencing batch reactor (A2N- SBR) fed with domestic wastewater was operated to examine the effect of varying ratios of influent COD/P, COD/TN and TN/P on the nutrient removal. With the increased COD/P, the phosphorus removals exhibited an upward trend. The influent TN/P ratios had a positive linear correlation with the phosphorus removal efficiencies, mainly because nitrates act as electron acceptors for the phosphorus uptake in the A2N-SBR. Moreover, it was found that lower COD/TN ratio, e.g. 3.5, did not significantly weaken the phosphorus removal, though the nitrogen removal first decreased greatly. The optimal phosphorus and nitrogen removals of 94% and 91%, respectively were achieved with influent COD/P and COD/ TN ratios of 19.9 and 9.9, respectively. Additionally, a real-time control strategy for A2N-SBR can be undertaken based on some characteristic points of pH, redox potential (ORP) and dissolved oxygen (DO) profiles in order to obtain the optimum hydraulic retention time (HRT) and improve the operating reliabili

Nitrogen and phosphorus leakage in ecological recycling agriculture

In this report we quantify nitrogen and phosphorus leakage on three farms in the BERAS project. The study is based on direct measurements of nitrogen and phosphorus concentration in drainage water and water flow measurements