Worldwide cloud cover model

Classifying worldwide cloudiness into homogeneous regions, using a satellite data set containing day IR, night IR, incoming, and absorbed solar radiation measurements on a 2.5-degree latitude-longitude grid is considered. Methods of analysis are presented

Isolation of Cellulolytic Microfungi Involved in Wood-Waste Decomposition: Prospects for Enzymatic Hydrolysis of Cellulosic Wastes

Wood-wastes from dump-sites at Okobaba Saw-mills on the western part of the Lagos lagoon were examined for cellulolytic microorganisms. Cellulolytic microfungi were isolated from the wastes using minimal salt agar medium containing 0.2% (w/v) crystalline cellulose, sugarcane pulp, corn cob or saw-dust as sole carbon/energy source. The colonies of cellulolytic microfungi which appeared on the plates increased in size and number as the incubation period (days) increased. Among the fungal isolates were two pathogenic Aspergilli (A flavus and A fumigatus), three different black Aspergilli (herein designated as A.niger I, A.niger II and A.niger III), Botrytis cinerea, Fusarium species and Penicillium species. Cell-free filtrates of 7 – day cultures of A.flavus, A.niger I, A.niger II, B. cinerea and P.species grown on the minimal salt broth supplemented with crystalline cellulose as sole carbon/energy source showed very significant CM–cellulase activity. P. species gave a very high value that was over 4 times the value for the closest organism, A.niger II. There is a good propect for cellulase production using the virgin strain of P. species isolated from the wood-wastes

General purpose simulation system of the data management system for Space Shuttle mission 18

A simulation program for the flow of data through the Data Management System of Spacelab and Space Shuttle was presented. The science, engineering, command and guidance, navigation and control data were included. The programming language used was General Purpose Simulation System V (OS). The science and engineering data flow was modeled from its origin at the experiments and subsystems to transmission from Space Shuttle. Command data flow was modeled from the point of reception onboard and from the CDMS Control Panel to the experiments and subsystems. The GN&C data flow model handled data between the General Purpose Computer and the experiments and subsystems. Mission 18 was the particular flight chosen for simulation. The general structure of the program is presented, followed by a user's manual. Input data required to make runs are discussed followed by identification of the output statistics. The appendices contain a detailed model configuration, program listing and results

Interacting Supernovae: Types IIn and Ibn

Supernovae (SNe) that show evidence of strong shock interaction between their ejecta and pre-existing, slower circumstellar material (CSM) constitute an interesting, diverse, and still poorly understood category of explosive transients. The chief reason that they are extremely interesting is because they tell us that in a subset of stellar deaths, the progenitor star may become wildly unstable in the years, decades, or centuries before explosion. This is something that has not been included in standard stellar evolution models, but may significantly change the end product and yield of that evolution, and complicates our attempts to map SNe to their progenitors. Another reason they are interesting is because CSM interaction is an efficient engine for making bright transients, allowing super-luminous transients to arise from normal SN explosion energies, and allowing transients of normal SN luminosities to arise from sub-energetic explosions or low radioactivity yield. CSM interaction shrouds the fast ejecta in bright shock emission, obscuring our normal view of the underlying explosion, and the radiation hydrodynamics of the interaction is challenging to model. The CSM interaction may also be highly non-spherical, perhaps linked to binary interaction in the progenitor system. In some cases, these complications make it difficult to definitively tell the difference between a core-collapse or thermonuclear explosion, or to discern between a non-terminal eruption, failed SN, or weak SN. Efforts to uncover the physical parameters of individual events and connections to possible progenitor stars make this a rapidly evolving topic that continues to challenge paradigms of stellar evolution.Comment: Final draft of a chapter in the "SN Handbook". Accepted. 25 pages, 3 fig

Spin g-factor due to electronic interactions in graphene

The gyromagnetic factor is an important physical quantity relating the magnetic-dipole moment of a particle to its spin. The electron spin g-factor in vacuo is one of the best model-based theoretical predictions ever made, showing agreement with the measured value up to ten parts per trillion. However, for electrons in a material the g-factor is modified with respect to its value in vacuo because of environment interactions. Here, we show how interaction effects lead to the spin g-factor correction in graphene by considering the full electromagnetic interaction in the framework of pseudo-QED. We compare our theoretical prediction with experiments performed on graphene deposited on SiO2 and SiC, and we find a very good agreement between them.Comment: Improved version of the manuscript; valley g-factor part has been remove

Observed Consequences of Presupernova Instability in Very Massive Stars

This chapter concentrates on the deaths of very massive stars, the events leading up to their deaths, and how mass loss affects the resulting death. The previous three chapters emphasized the theory of wind mass loss, eruptions, and core collapse physics, but here we emphasize mainly the observational properties of the resulting death throes. Mass loss through winds, eruptions, and interacting binaries largely determines the wide variety of different types of supernovae that are observed, as well as the circumstellar environments into which the supernova blast waves expand. Connecting these observed properties of the explosions to the initial masses of their progenitor stars is, however, an enduring challenge and is especially difficult for very massive stars. Superluminous supernovae, pair instability supernovae, gamma ray bursts, and "failed" supernovae are all end fates that have been proposed for very massive stars, but the range of initial masses or other conditions leading to each of these (if they actually occur) are still very certain. Extrapolating to infer the role of very massive stars in the early universe is essentially unencumbered by observational constraints and still quite dicey.Comment: 39 pages, 5 figures, to appear as chapter in the book "Very Massive Stars in the Local Universe", ed. J. Vin

Early season depletion of dissolved iron in the Ross Sea polynya: Implications for iron dynamics on the Antarctic continental shelf

The Ross Sea polynya is among the most productive regions in the Southern Ocean and may constitute a significant oceanic CO2 sink. Based on results from several field studies, this region has been considered seasonally iron limited, whereby a winter reserve of dissolved iron (dFe) is progressively depleted during the growing season to low concentrations (similar to 0.1 nM) that limit phytoplankton growth in the austral summer (December-February). Here we report new iron data for the Ross Sea polynya during austral summer 2005-2006 (27 December-22 January) and the following austral spring 2006 (16 November-3 December). The summer 2005-2006 data show generally low dFe concentrations in polynya surface waters (0.10 +/- 0.05 nM in upper 40 m, n = 175), consistent with previous observations. Surprisingly, our spring 2006 data reveal similar low surface dFe concentrations in the polynya (0.06 +/- 0.04 nM in upper 40 m, n = 69), in association with relatively high rates of primary production (similar to 170-260 mmol C m(-2) d(-1)). These results indicate that the winter reserve dFe may be consumed relatively early in the growing season, such that polynya surface waters can become iron limited as early as November; i.e., the seasonal depletion of dFe is not necessarily gradual. Satellite observations reveal significant biomass accumulation in the polynya during summer 2006-2007, implying significant sources of new dFe to surface waters during this period. Possible sources of this new dFe include episodic vertical exchange, lateral advection, aerosol input, and reductive dissolution of particulate iron

Effect of carbon sources on cellulase (EC 3. 2. 1. 4) production by Penicillium chrysogenum PCL501

The effects of glucose, crystalline cellulose and sawdust of Mitragyna cilata on the growth and cellulase production, inferred from cellulase (EC 3. 2. 1. 4) activity, of Penicillium chrysogenum PCL501 was determined. Glucose-containing media gave the highest mycelia weight of 1.78 mg mL-1 in 120 h of incubation. This is about 3.5 – 4.5 times the maximum weights of 0.51 and 0.40 mg mL-1 respectively obtained from the cultures containing cellulose and sawdust. The cultures containing crystalline cellulose and sawdust produced extracellular protein with cellulase (EC 3. 2. 1. 4) activity whereas glucose-containing cultures yielded very low protein and no significant cellulase activity. Maximum protein content of 0.02, 0.13 and 0.46 mg mL-1 respectively were obtained from the cultures containing glucose, cellulose and sawdust. Peak cellulase activity values of 100.0 and 92.2 Units L-1 respectively were obtained for the cultures containing cellulose and sawdust. There is a correlation between the protein released and cellulase activity of the culture filtrates. P. chrysogenum PCL501 produces extracellular proteins with significant cellulase activity in media containing cellulose and sawdust but not in glucose-containing medium. Sawdust is indicated as a good inducer of cellulase activity in the organism. The waste cellulosic material can be used as low-cost carbon source for commercial cellulase production

The structure of latherin, a surfactant allergen protein from horse sweat and saliva

Latherin is a highly surface-active allergen protein found in the sweat and saliva of horses and other equids. Its surfactant activity is intrinsic to the protein in its native form, and is manifest without associated lipids or glycosylation. Latherin probably functions as a wetting agent in evaporative cooling in horses, but it may also assist in mastication of fibrous food as well as inhibition of microbial biofilms. It is a member of the PLUNC family of proteins abundant in the oral cavity and saliva of mammals, one of which has also been shown to be a surfactant and capable of disrupting microbial biofilms. How these proteins work as surfactants while remaining soluble and cell membrane-compatible is not known. Nor have their structures previously been reported. We have used protein nuclear magnetic resonance spectroscopy to determine the conformation and dynamics of latherin in aqueous solution. The protein is a monomer in solution with a slightly curved cylindrical structure exhibiting a ‘super-roll’ motif comprising a four-stranded anti-parallel β-sheet and two opposing α-helices which twist along the long axis of the cylinder. One end of the molecule has prominent, flexible loops that contain a number of apolar amino acid side chains. This, together with previous biophysical observations, leads us to a plausible mechanism for surfactant activity in which the molecule is first localized to the non-polar interface via these loops, and then unfolds and flattens to expose its hydrophobic interior to the air or non-polar surface. Intrinsically surface-active proteins are relatively rare in nature, and this is the first structure of such a protein from mammals to be reported. Both its conformation and proposed method of action are different from other, non-mammalian surfactant proteins investigated so far