Ambient pH strongly influences the synthesis of secreted enzymes, permeases and exported metabolites by a wide range of micro-organisms. For example, numerous microbes secrete acid phosphatase in acidic environments and alkaline phosphatase in alkaline environments. Only in the ascomycete Aspergillus nidulans, however, is characterization [ 1-51 of the pH-regulatory system sufficiently advanced...

cold hardiness is one of the most common adaptations of insects at low temperatures. to understand the cold hardiness strategy of beet armyworm, spodoptera exigua (hübner), six temperature treatments were tested on the last instar larvae. supercooling points of treatments were not significantly different. two sugars, glucose and trehalose, as well as three polyols, myo-inositol, glycerol and so...

the effect of hydraulic retention time in a range from 1.0-5.5 days was evaluated in a laboratoryscaleanaerobic fixed bed reactor packed with a hybrid material composed of tire rubber and zeolite. underthese conditions, cod removal efficiencies varied from 28.3% to 82.1%, respectively. over the more than 6months of operation, no clogging was observed. the results obtained demonstrated that this...

Abstract Purpose We sought to identify plant traits important for initial establishment of a globally invasive shrub, Prosopis spp. (mesquite), by quantifying morphological and ecophysiological responses seedlings contrasting moisture regimes. Our model was velutina , prominent invader North American semi-desert grasslands. Methods Seedlings received one three watering levels corresponding regi...

the main objective of a research program, whose output is presented here, has been to estimate “ventilation coefficients”, a critical parameter in determining air pollution concentration near the surface ground which signifies the ability for natural ventilation of an air shed in an urban or rural area. relevant measured data from the city of tehran has been used to calibrate and further de...

Atlantic salmon (Salmo salar) parr were exposed in two outdoor experiments, ranging in duration from 52 to 137 days, to spectral treatments: (1) natural sunlight (=present ambient UVB level), (2) solar radiation supplemented with enhanced UVB radiation from lamps simulating 20% or 8% stratospheric ozone loss or (3) UVB-depleted sunlight achieved by screening with Mylar-D film. The growth, condi...

The effect of the ambient conditions in the growth chamber of the molecular beam epitaxy machine during the growth of GaAs/Ales,Gae(i,As structures was investigated. Both growth-interrupted (120 s at each heterointerface) and uninterrupted surfaces and interfaces were evaluated using a growth temperature of 580 “C. Two ambient conditions were studied: (a) 1 x 10-r’ Torr 02; and (b) ultrahigh va...

Global linear stability analysis of a self-similar solution describing a relativistic shell decelerated by an ambient medium is performed. The system is shown to be subject to the convective Rayleigh-Taylor instability, with a rapid growth of eigenmodes having angular scale much smaller than the causality scale. The growth rate appears to be largest at the interface separating the shocked eject...

Over the last thirty years, China's major cities have experienced significant income and population growth. Much of this growth has been fueled by urban production spurred by world demand. Using a unique cross-city panel data set, we test several hypotheses concerning the relationship between home prices, wages, foreign direct investment and ambient air pollution across major Chinese cities. Ho...

Changing environmental conditions set against a backdrop of high exploitation can result in severe consequences for commercially harvested stocks. The collapse of the Eastern Scotian Shelf cod (Gadus morhua L.) off eastern Canada was primarily due to overexploitation but may have been exacerbated by a widespread temperature decline. Recent studies have called for accurate determination of ambie...