983 resultados para Production Firms


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The open development model of software production has been characterized as the future model of knowledge production and distributed work. Open development model refers to publicly available source code ensured by an open source license, and the extensive and varied distributed participation of volunteers enabled by the Internet. Contemporary spokesmen of open source communities and academics view open source development as a new form of volunteer work activity characterized by hacker ethic and bazaar governance . The development of the Linux operating system is perhaps the best know example of such an open source project. It started as an effort by a user-developer and grew quickly into a large project with hundreds of user-developer as contributors. However, in hybrids , in which firms participate in open source projects oriented towards end-users, it seems that most users do not write code. The OpenOffice.org project, initiated by Sun Microsystems, in this study represents such a project. In addition, the Finnish public sector ICT decision-making concerning open source use is studied. The purpose is to explore the assumptions, theories and myths related to the open development model by analysing the discursive construction of the OpenOffice.org community: its developers, users and management. The qualitative study aims at shedding light on the dynamics and challenges of community construction and maintenance, and related power relations in hybrid open source, by asking two main research questions: How is the structure and membership constellation of the community, specifically the relation between developers and users linguistically constructed in hybrid open development? What characterizes Internet-mediated virtual communities and how can they be defined? How do they differ from hierarchical forms of knowledge production on one hand and from traditional volunteer communities on the other? The study utilizes sociological, psychological and anthropological concepts of community for understanding the connection between the real and the imaginary in so-called virtual open source communities. Intermediary methodological and analytical concepts are borrowed from discourse and rhetorical theories. A discursive-rhetorical approach is offered as a methodological toolkit for studying texts and writing in Internet communities. The empirical chapters approach the problem of community and its membership from four complementary points of views. The data comprises mailing list discussion, personal interviews, web page writings, email exchanges, field notes and other historical documents. The four viewpoints are: 1) the community as conceived by volunteers 2) the individual contributor s attachment to the project 3) public sector organizations as users of open source 4) the community as articulated by the community manager. I arrive at four conclusions concerning my empirical studies (1-4) and two general conclusions (5-6). 1) Sun Microsystems and OpenOffice.org Groupware volunteers failed in developing necessary and sufficient open code and open dialogue to ensure collaboration thus splitting the Groupware community into volunteers we and the firm them . 2) Instead of separating intrinsic and extrinsic motivations, I find that volunteers unique patterns of motivations are tied to changing objects and personal histories prior and during participation in the OpenOffice.org Lingucomponent project. Rather than seeing volunteers as a unified community, they can be better understood as independent entrepreneurs in search of a collaborative community . The boundaries between work and hobby are blurred and shifting, thus questioning the usefulness of the concept of volunteer . 3) The public sector ICT discourse portrays a dilemma and tension between the freedom to choose, use and develop one s desktop in the spirit of open source on one hand and the striving for better desktop control and maintenance by IT staff and user advocates, on the other. The link between the global OpenOffice.org community and the local end-user practices are weak and mediated by the problematic IT staff-(end)user relationship. 4) Authoring community can be seen as a new hybrid open source community-type of managerial practice. The ambiguous concept of community is a powerful strategic tool for orienting towards multiple real and imaginary audiences as evidenced in the global membership rhetoric. 5) The changing and contradictory discourses of this study show a change in the conceptual system and developer-user relationship of the open development model. This change is characterized as a movement from hacker ethic and bazaar governance to more professionally and strategically regulated community. 6) Community is simultaneously real and imagined, and can be characterized as a runaway community . Discursive-action can be seen as a specific type of online open source engagement. Hierarchies and structures are created through discursive acts. Key words: Open Source Software, open development model, community, motivation, discourse, rhetoric, developer, user, end-user

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We reported the presence of a 80 kDa polypeptide in porcine follicular fluid that inhibited the binding of 125I-radiolabelled hFSH as well as hCG to the rat ovarian gonadotropin receptors. In the present study, the biological activity of the receptor binding inhibitor is determined using an in vitro bioassay procedure. Granulosa cells isolated from PMSG primed immature rat ovaries respond to exogenously added gonadotropins in terms of progesterone production. Addition of fractions containing the gonadotropin receptor binding inhibitory activity inhibited progesterone production stimulated by the gonadotropins in a dose-dependent fashion. The receptor binding inhibitory activity was also capable of inhibiting progesterone production stimulated by PMSG, which has both FSH- and LH-like activities in rats. In contrast, progesterone production stimulated by dbcAMP was not inhibited by the receptor binding inhibitor. This result indicates that the site of action of the inhibitor is proximal to the formation of the cAMP. The above observations point out to a possible role for this factor in modulating gonadotropin activity at the ovarian level.

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Oral cancer is the seventh most common cancer worldwide and its incidence is increasing. The most important risk factors for oral cancer are chronic alcohol consumption and tobacco smoking, up to 80 % of oral carcinomas are estimated to be caused by alcohol and tobacco. They both trigger an increased level of salivary acetaldehyde, during and after consumption, which is believed to lead to carcinogenesis. Acetaldehyde has multiple mutagenic features and it has recently been classified as a Group 1 carcinogen for humans by the International Agency for Research on Cancer. Acetaldehyde is metabolized from ethanol by microbes of oral microbiota. Some oral microbes possess alcohol dehydrogenase enzyme (ADH) activity, which is the main enzyme in acetaldehyde production. Many microbes are also capable of acetaldehyde production via alcohol fermentation from glucose. However, metabolism of ethanol into acetaldehyde leads to production of high levels of this carcinogen. Acetaldehyde is found in saliva during and after alcohol consumption. In fact, rather low ethanol concentrations (2-20mM) derived from blood to saliva are enough for microbial acetaldehyde production. The high acetaldehyde levels in saliva after alcohol challenge are explained by the lack of oral microbiota and mucosa to detoxify acetaldehyde by metabolizing it into acetate and acetyl coenzymeA. The aim of this thesis project was to specify the role of oral microbes in the in vitro production of acetaldehyde in the presence of ethanol. In addition, it was sought to establish whether microbial metabolism could also produce acetaldehyde from glucose. Furthermore, the potential of xylitol to inhibit ethanol metabolism and acetaldehyde production was explored. Isolates of oral microbes were used in the first three studies. Acetaldehyde production was analyzed after ethanol, glucose and fructose incubation with gas chromatography measurement. In studies I and III, the ADH enzyme activity of some microbes was measured by fluorescence. The effect of xylitol was analyzed by incubating microbes with ethanol and xylitol. The fourth study was made ex vivo and microbial samples obtained from different patient groups were analyzed. This work has demonstrated that isolates of oral microbiota are able to produce acetaldehyde in the presence of clinically relevant ethanol and glucose concentrations. Significant differences were found between microbial species and isolates from different patient groups. In particular, the ability of candidal isolates from APECED patients to produce significantly more acetaldehyde in glucose incubation compared to healthy and cancer patient isolates is an interesting observation. Moreover, xylitol was found to reduce their acetaldehyde production significantly. Significant ADH enzyme activity was found in the analyzed high acetaldehyde producing streptococci and candida isolates. In addition, xylitol was found to reduce the ADH enzyme activity of C. albicans. Some results from the ex vivo study were controversial, since acetaldehyde production did not correlate as expected with the amount of microbes in the samples. Nevertheless, the samples isolated from patients did produce significant amounts of acetaldehyde with a clinically relevant ethanol concentration.

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Cryogel matrices composed of different polymeric blends were synthesized, yielding a unique combination of hydrophilicity and hydrophobicity with the presence or absence of charged surface. Four such cryogel matrices composed of polyacrylamide-chitosan (PAAC), poly(N-isopropylacrylamide)-chitosan, polyacrylonitrile (PAN), and poly(N-isopropylacrylamide) were tested for growth of different hybridoma cell lines and production of antibody in static culture. All the matrices were capable for the adherence of hybridoma cell lines 6A4D7, B7B10, and H9E10 to the polymeric surfaces as well as for the efficient monoclonal antibody (mAb) production. PAAC proved to be relatively better in terms of both mAb production and cell growth. Further, PAAC cryogel was designed into three different formats, monolith, disks, and beads, and used as packing material for packed-bed bioreactor. Longterm cultivation of 6A4D7 cell line on PAAC cryogel scaffold in all the three formats could be successfully done for a period of 6 weeks under static conditions. Continuous packed-bed bioreactor was setup using 6A4D7 hybridoma cell line in the three reactor formats. The reactors ran continuously for a period of 60 days during which mAb production and metabolism of cells in the bioreactors were monitored periodically. The monolith bioreactor performed most efficiently over a period of 60 days and produced a total of 57.5 mg of antibody in the first 30 days (in 500 mL) with a highest concentration of 115 mu g mL(-1), which is fourfold higher than t-flask culture. The results demonstrate that appropriate chemistry and geometry of the bioreactor matrix for cell growth and immobilization can enhance the reactor productivity. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 27: 170-180, 2011

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The relative quantum yields, phi*, for the production of I*(P-2(1/2)) at 266, 280, and similar to 305 nm are reported for a series of primary alkyl iodides using the technique of two-photon laser-induced fluorescence for the detection of I(P-2(3/2)) and I*(P-2(1/2)) atoms. Results are analyzed by invoking the impulsive energy disposal model, which summarizes the dynamics of dissociation as a single parameter. Comparison of our data with those calculated by a more sophisticated time-dependent quantum mechanical model is also made. Near the red edge of the alkyl iodide A band, absorption contribution from the (3)Q(1) state is important and the dynamics near the (3)Q(0)-(1)Q(1) curve-crossing region seem to be influenced by the kinematics of the dissociation process

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Red sandalwood (Pterocarpus santalinus L.), belonging to the family Fabaceae, is one of the most valuable trees, and has limited distribution in India. In view of its high price, restricted distribution and usefulness as a timber tree, there is urgent need to obtain improved lines, in both quality and quantity. We have established a method for production of complete plantlets by tissue culture. We report here the successful development of red sandalwood plantlets by induction of multiple shoots from shoot tips, and successful transfer of micropropagated plants to soil.

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It has been noted that at high energy the Ricci scalar is manifested in two different ways, as a matter field as well as a geometrical field (which is its usual nature even at low energy). Here, using the material aspect of the Ricci scalar, its interaction with Dirac spinors is considered in four-dimensional curved spacetime. We find that a large number of fermion-antifermion pairs can be produced by the exponential expansion of the early universe.

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Carbon fibres/particles can be satisfactory reinforcing material in polymer, ceramic and metal matrices. Carbon fibres/particles reinforced polymer matrix composites and ceramic matrix composites are being used extensively in critical areas of application, but carbon fibre - metal matrix composites have not reached that stage yet. This paper discusses the salient aspects of production and specific properties of carbon fibre/particle reinforced cast metal matrix composites. It is envisaged that these materials will find extensive applications where cost, weight and thermal expansion are the key factors.

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Pseudomonas maltophilia CSV89, a soil bacterium, produces an extracellular biosurfactant, ''Biosur-Pm''. The partially purified product is nondialyzable and chemically composed of 50% protein and 12-15% sugar, which indicates the complex nature of Biosur-Pm. It reduces the surface tension of water from 73 to 53 x 10(-3) N m(-1) and has a critical micellar concentration of 80 mg/l. Compared to aliphatic hydrocarbons, Biosur-Pm shows good activity against aromatic hydrocarbons. The emulsion formed is stable and does not require any metal ions for emulsification. The kinetics of Biosur-Pm production suggest that its synthesis isa growth-associated and pH-dependent process. At pH 7.0, cells produced more Biosur-Pm with less cell surface hydrophobicity. At pH 8.0, however, the cells produced less Biosur-Pm with more cell surface hydrophobicity and showed a twofold higher affinity for aromatic hydrocarbons compared to the cells grown at pH 7.0. The Biosur-Pm showed a pH-dependent release, stimulated growth of the producer strain on mineral salts medium with 1-naphthoic acid when added externally, and facilitated the conversion of salicylate to catechol. All these results suggest that Biosur-Pm is probably a cell-wall component and helps in hydrocarbon assimilation/uptake.

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The moist tropical forests of the Western Ghats of India are pockmarked with savanna-grasslands created and managed by local agricultural communities. A sample of such savanna-grasslands with differing growing conditions was studied in terms of peak above-ground biomass, monthly growth, and cumulative production under different clipping treatments. The herblayer was found to be dominated by perennial C4 grasses, with Eulalia trispicata, Arundinella metzii and Themeda triandra being common to all sites. Peak biomass ranged between 3.3-5.9 t/ha at sites most favourable for grass production. Across these sites, peak biomass was found to be inversely related to the number of rainy days during the growing season, suggesting that growth may be light-limited. This hypothesis is supported by the observation that growth is most rapid immediately after the easing of the monsoon. Single clips early in the growing season had no negative or a slightly positive effect on production, but mid-season single clips or continuous frequent clipping reduced production by as much as 40%. The results suggest that, while indiscriminate grazing may certainly be deleterious, it is possible to obtain sustained high yields from forest lands managed for grass production without totally excluding grazing.

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In this paper we have assessed the availability of land and the potential for biomass production in India to meet various demands for biomass, including modern bioenergy. This is estimated by considering the various demands on land and its suitability. The biomass production potential of energy plantations is assessed for different agroecological zones. The total woody biomass production is estimated to be 321 Mt, based on biomass productivity in the range 2 to 17 t/ha/yr for the different agro-ecological zones and considering the conservative estimate of 43 Mha land availability for biomass production. A surplus of 231 Mt of biomass (after meeting the increased demand for fuelwood and timber by the year 2010) is estimated to be available for energy, which has an electricity generation potential of 231 TWh. As a first step, only the feasible physical potential of biomass production is assessed, along with an analysis of barriers. The potential costs and benefits of biomass production strategy are not analysed. (C) 1999 Elsevier Science Ltd. All rights reserved.

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Results of Western blot analysis carried out with an interstitial cell extract from male guinea pig and ovarian extract from immature female rats administered equine chorionic gonadotropin (eCG) provide supportive evidence to our earlier suggestion that an 8-kDa peptide is involved in acquisition of steroidogenic capacity by the rat Leydig cells. It was found that though the signal was observed in other tissues such as liver, kidney and lung which do not produce gonadal hormones, the peptide was modulated only by lutenizing hormone (LH) in the rat Leydig cells.

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The quantum yield of I*((2)p(1/2)) production from CH3I photolysis at 236 nm in the gas phase has been measured as 0.69 +/- 0.03. The implication is that direct excitation to the (1)Q(1) excited state is significant at this wavelength. The dynamics of I* formation at other excitation energies covering the entire A-band of absorption of CH3I has been discussed in the light of this measurement.

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Aluminium nitride (AlN)-Al matrices reinforced with Al2O3 particulate have been fabricated by reactive infiltration of Al-2% Mg alloy into Al2O3 preforms in N-2 in the temperature range of 900-1075 degreesC. The growth of composites of useful thickness was facilitated by the presence of a Mg-rich external getter, in the absence of which composite growth is self-limiting and terminates prematurely. Successful growth of composites has been attributed to the reduction in residual oxygen partial pressure brought about by the reaction with oxygen of highly volatile Mg in the getter alloy. The microstructure of the matrix consists of AlN-rich regions contiguous with the particulate with metal-rich channels in-between, thereby suggesting that nitridation initiates by preferential wicking of alloy along the particle surfaces. The increase in nitride content of the matrix with temperature is consistent with hardness values that vary between similar to3 and 10 GPa. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.