title: XP customer practices: A grounded theory

authors: Martin, Angela

subjects: computer science

abstract: The Customer is a critical role in XP, but almost all XP practices are presented for developers by developers. While XP calls for Real Customer Involvement, it does not explain what XP Customers should do, nor how they should do it. Using Grounded Theory, we discovered eight customer practices used by successful XP teams: Customer Boot Camp, Customer’s Apprentice, Customer Pairing, and Programmer’s Holiday support the well-being and effectiveness of customers; Programmer On-site and Road shows support team and organization interactions; and Big Picture Up Front and Re-calibration support Customers steering the whole project. By adopting these processes, XP Customers and teams can work faster and more sustainably.

text: XP customer practices: A grounded theory The Customer is a critical role in XP, but almost all XP practices are presented for developers by developers. While XP calls for Real Customer Involvement, it does not explain what XP Customers should do, nor how they should do it. Using Grounded Theory, we discovered eight customer practices used by successful XP teams: Customer Boot Camp, Customer’s Apprentice, Customer Pairing, and Programmer’s Holiday support the well-being and effectiveness of customers; Programmer On-site and Road shows support team and organization interactions; and Big Picture Up Front and Re-calibration support Customers steering the whole project. By adopting these processes, XP Customers and teams can work faster and more sustainably.

year: 2009

title: Bioconversion of Glycerol to Dihydroxyacetone by immobilized Gluconacetobacter xylinus cells

authors: Black, Cathryn Sesengel

subjects: Glycerol

abstract: Dihydroxyacetone, (DHA) is one of the primary ingredients used in tanning products by the cosmetic industry. DHA reacts with the free amino acids on the epidermis to form a tan-like appearance. DHA is also a building block for lactic acid; that is, a common ingredient in the food industry. In the pharmaceutical industry, DHA is used as a precursor for 1, 2-propylene glycerol and methotrexate. 
Due to the Food and Drug Administration’s strict regulations, DHA is produced via microbial synthesis. This is because the chemical synthesis involves toxic chemical reactions with epichlorohydrin. This poses problems with a chemical widely used for human application. Currently, the industrial process of DHA is carried out under microbial synthesis of glycerol. The strain, Gluconobacter oxydans produces high DHA yields although its productivity is low. As a result, its high cost of production is reflected in its price.
Glycerol is the only organic compound that can be converted into DHA. The conversion requires oxidation of the secondary hydroxyl group by glycerol dehydrogenase (GlyDH). In this study, DHA was converted from glycerol using Gluconacetobacter xylinus (G.xylinus) in a large-scale reactor. Previously the strain, G.xylinus, has been shown to produce high DHA yields under immobilization. 
In this study, G.xylinus was immobilized inside two carrier materials- calcium alginate and chitosan-coated alginate beads. A series of investigations were carried out to determine the DHA conversion efficiency using the mentioned carriers. The conversion efficiency of alginate immobilized cells was investigated under varying initial glycerol concentrations of: 1%, 2%, 4% and 7% (w/v) and aeration rates of: 0.3, 0.6 and 1.0 vvm. This study found that the optimal glycerol concentration was at 2% (w/v) and the optimal aeration rate was at 0.3 vvm. The DHA conversion efficiency of chitosan-alginate immobilized cells was also tested under the same aeration rate previously mentioned. The investigation found that chitosan coating provided greater stability to the alginate matrix with increased aeration rate. The optimal aeration rate was found at 1.0 vvm.

text: Bioconversion of Glycerol to Dihydroxyacetone by immobilized Gluconacetobacter xylinus cells Dihydroxyacetone, (DHA) is one of the primary ingredients used in tanning products by the cosmetic industry. DHA reacts with the free amino acids on the epidermis to form a tan-like appearance. DHA is also a building block for lactic acid; that is, a common ingredient in the food industry. In the pharmaceutical industry, DHA is used as a precursor for 1, 2-propylene glycerol and methotrexate. 
Due to the Food and Drug Administration’s strict regulations, DHA is produced via microbial synthesis. This is because the chemical synthesis involves toxic chemical reactions with epichlorohydrin. This poses problems with a chemical widely used for human application. Currently, the industrial process of DHA is carried out under microbial synthesis of glycerol. The strain, Gluconobacter oxydans produces high DHA yields although its productivity is low. As a result, its high cost of production is reflected in its price.
Glycerol is the only organic compound that can be converted into DHA. The conversion requires oxidation of the secondary hydroxyl group by glycerol dehydrogenase (GlyDH). In this study, DHA was converted from glycerol using Gluconacetobacter xylinus (G.xylinus) in a large-scale reactor. Previously the strain, G.xylinus, has been shown to produce high DHA yields under immobilization. 
In this study, G.xylinus was immobilized inside two carrier materials- calcium alginate and chitosan-coated alginate beads. A series of investigations were carried out to determine the DHA conversion efficiency using the mentioned carriers. The conversion efficiency of alginate immobilized cells was investigated under varying initial glycerol concentrations of: 1%, 2%, 4% and 7% (w/v) and aeration rates of: 0.3, 0.6 and 1.0 vvm. This study found that the optimal glycerol concentration was at 2% (w/v) and the optimal aeration rate was at 0.3 vvm. The DHA conversion efficiency of chitosan-alginate immobilized cells was also tested under the same aeration rate previously mentioned. The investigation found that chitosan coating provided greater stability to the alginate matrix with increased aeration rate. The optimal aeration rate was found at 1.0 vvm.

year: 2013

title: Role of tephra in dating Polynesian settlement and impact, New Zealand

authors: Lowe, David J.

subjects: tephrochronology

abstract: Tephrochronology in its original sense is the use of tephra layers as time-stratigraphic marker beds to establish numerical or relative ages (Lowe and Hunt, 2001). Tephra layers have been described and studied in New Zealand for more than 160 years (the German naturalist and surgeon Ernst Dieffenbach described ‘recognizable’ tephra sections in his 1843 book Travels in New Zealand), and the first isopach map, showing fallout from the deadly plinian basaltic eruption of Mt Tarawera on 10 June 1886, was published in 1888 (Lowe, 1990; Lowe et al., 2002). More recently, a wide range of tephra-related paleoenvironmental research has been undertaken (e.g., Lowe and Newnham, 1999; Newnham and Lowe, 1999; Newnham et al., 1999, 2004; Shane, 2000), including new advances in the role of tephra in linking and dating sites containing evidence for abrupt climatic change (e.g., Newnham and Lowe, 2000; Newnham et al., 2003). Here we focus on the use of tephrochronology in dating the arrival and impacts of the first humans in New Zealand, a difficult problem for which this technique has proven to be of critical importance.

text: Role of tephra in dating Polynesian settlement and impact, New Zealand Tephrochronology in its original sense is the use of tephra layers as time-stratigraphic marker beds to establish numerical or relative ages (Lowe and Hunt, 2001). Tephra layers have been described and studied in New Zealand for more than 160 years (the German naturalist and surgeon Ernst Dieffenbach described ‘recognizable’ tephra sections in his 1843 book Travels in New Zealand), and the first isopach map, showing fallout from the deadly plinian basaltic eruption of Mt Tarawera on 10 June 1886, was published in 1888 (Lowe, 1990; Lowe et al., 2002). More recently, a wide range of tephra-related paleoenvironmental research has been undertaken (e.g., Lowe and Newnham, 1999; Newnham and Lowe, 1999; Newnham et al., 1999, 2004; Shane, 2000), including new advances in the role of tephra in linking and dating sites containing evidence for abrupt climatic change (e.g., Newnham and Lowe, 2000; Newnham et al., 2003). Here we focus on the use of tephrochronology in dating the arrival and impacts of the first humans in New Zealand, a difficult problem for which this technique has proven to be of critical importance.

year: 2004