Effects of Nitrogen Fertilization on Monoterpenes of Jack Pine Seedlings and Weight Gain of Jack Pine Budworm (Lepidoptera: Tortricidae)

Nine-month old jack pine (Pinus banksiana) seedlings were grown in a greenhouse under four nitrogen fertilization regimes. Levels of total nitrogen and five monoterpenes in new foliage were measured. Fertilization resulted in four significantly different levels of foliar nitrogen; means ranged from 1.8-4.5 percent dry weight. Contrary to predictions of resource availability theory, seedlings grown under the highest fertilization regime had higher foliar monoterpene levels than seedlings in the other treatments. Newly molted, sixth-instar female jack pine budworm (Choristoneura pinus pinus [Lepidoptera: Tortricidae]) larvae were allowed to feed for four days on new foliage of the seedlings. Larvae that fed on low-nitrogen seedling gained less weight and process more vegetation than did larvae on high- nitrogen seedlings. Larval weight gain was positively related to foliar nitrogen

Adsorption of atomic and molecular oxygen on Si(100)2x1: coverage dependence of the Auger O KVV lineshape.

By means of Auger electron spectroscopy (AES) we have monitored the room temperature adsorption of O2 and N2O on the clean Si(0 0 1)2 × 1 surface. We have found, for the first time, a significant variation in the intensity ratio of the K L1 L1 and K L23 L23 O Auger lines in the submonolayer range. This variation can be related to a change in bonding configuration of the oxygen atom/molecule in the initial adsorption stage in which the influence of inter-atomic matrix elements of the Auger process cannot be neglected

Gallium Arsenide solar cell radiation damage experiment

Gallium arsenide (GaAs) solar cells for space applications from three different manufactures were irradiated with 10 MeV protons or 1 MeV electrons. The electrical performance of the cells was measured at several fluence levels and compared. Silicon cells were included for reference and comparison. All the GaAs cell types performed similarly throughout the testing and showed a 36 to 56 percent power areal density advantage over the silicon cells. Thinner (8-mil versus 12-mil) GaAs cells provide a significant weight reduction. The use of germanium (Ge) substrates to improve mechanical integrity can be implemented with little impact on end of life performance in a radiation environment

Cosmic Strings Stabilized by Fermion Fluctuations

We provide a thorough exposition of recent results on the quantum stabilization of cosmic strings. Stabilization occurs through the coupling to a heavy fermion doublet in a reduced version of the standard model. The study combines the vacuum polarization energy of fermion zero-point fluctuations and the binding energy of occupied energy levels, which are of the same order in a semi-classical expansion. Populating these bound states assigns a charge to the string. Strings carrying fermion charge become stable if the Higgs and gauge fields are coupled to a fermion that is less than twice as heavy as the top quark. The vacuum remains stable in the model, because neutral strings are not energetically favored. These findings suggest that extraordinarily large fermion masses or unrealistic couplings are not required to bind a cosmic string in the standard model.Comment: Based on talk by HW at QFEXT 11 (Benasque, Spain), 15p, uses ws-ijmpcs.cls (incl

A newly discovered population of the critically endangered false limpet Siphonaria compressa Allanson, 1958 (Pulmonata: Siphonariidae), with observations on its reproductive biology

The endangered false limpet, Siphonaria compressa, originally described by Allanson in 1958 from Langebaan Lagoon, Saldanha, has been found living in intertidal eelgrass meadows in the embayment of the Knysna River estuary at Bollard Bay, Leisure Isle, Knysna, South Africa. This represents only the second known site of occurrence of the species. Although classified by the IUCN as critically endangered, the Knysna population is viable.Acrobat Distiller 6.0 (Windows

The effect of nonlinear gain on the stability of evanescently coupled semiconductor laser arrays

We show that nonlinear gain saturation can enhance the stability of evanescently coupled semiconductor laser arrays.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71325/2/JAPIAU-73-1-459-1.pd

Action of metronidazole in combination with isoniazid & rifampicin on persisting organisms in experimental murine tuberculosis

To study the activity of metronidazole on persisting tubercle bacilli, BALB/c mice were infected with Mycobacterium tuberculosis and, after 14 days, treated with isoniazid (H) or rifampicin (R) or isoniazid + rifampicin (HR) for 2 months. An untreated group and a group treated with metronidazole (M) alone served as controls. At the end of 2 months, M was added to the H, R, and HR regimen in half the mice, and the treatment was continued for 1 more month in all mice. At the end of treatment, no viable organisms were detected in the lung or spleen of mice treated with HR or HRM regimens. In contrast, compared to the mice treated with R alone, the log10 colony forming units (cfu) of mice treated with RM were lower by 1.84 and 0.52 in the lung and spleen, respectively. Similarly, compared to the H group, the log10 cfu were lower by 0.67 in the spleen of mice treated with HM, and no additional effect due to M was seen in the lung. Three months after stopping treatment, viable organisms were isolated from both the organs of all the groups. However, the log10 cfu in the lung and spleen for the groups with metronidazole were below the log10 cfu for the respective single or 2 drug groups, except the log10 cfu in the lung for the RM group. These findings suggest that metronidazole, given with bactericidal drugs such as rifampicin and isoniazid may be of value in eliminating persisting tubercle bacilli, but further studies are warranted

Signal processing in local neuronal circuits based on activity-dependent noise and competition

We study the characteristics of weak signal detection by a recurrent neuronal network with plastic synaptic coupling. It is shown that in the presence of an asynchronous component in synaptic transmission, the network acquires selectivity with respect to the frequency of weak periodic stimuli. For non-periodic frequency-modulated stimuli, the response is quantified by the mutual information between input (signal) and output (network's activity), and is optimized by synaptic depression. Introducing correlations in signal structure resulted in the decrease of input-output mutual information. Our results suggest that in neural systems with plastic connectivity, information is not merely carried passively by the signal; rather, the information content of the signal itself might determine the mode of its processing by a local neuronal circuit.Comment: 15 pages, 4 pages, in press for "Chaos