10 resultados para Tensor product

em Helda - Digital Repository of University of Helsinki


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Many problems in analysis have been solved using the theory of Hodge structures. P. Deligne started to treat these structures in a categorical way. Following him, we introduce the categories of mixed real and complex Hodge structures. Category of mixed Hodge structures over the field of real or complex numbers is a rigid abelian tensor category, and in fact, a neutral Tannakian category. Therefore it is equivalent to the category of representations of an affine group scheme. The direct sums of pure Hodge structures of different weights over real or complex numbers can be realized as a representation of the torus group, whose complex points is the Cartesian product of two punctured complex planes. Mixed Hodge structures turn out to consist of information of a direct sum of pure Hodge structures of different weights and a nilpotent automorphism. Therefore mixed Hodge structures correspond to the representations of certain semidirect product of a nilpotent group and the torus group acting on it.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We all have fresh in our memory what happened to the IT sector only a few years ago when the IT-bubble burst. The upswing of productivity in this sector slowed down, investors lost large investments, many found themselves looking for a new job, and countless dreams fell apart. Product developers in the IT sector have experienced a large number of organizational restructurings since the IT boom, including rapid growth, downsizing processes, and structural reforms. Organizational restructurings seem to be a complex and continuous phenomenon people in this sector have to deal with. How do software product developers retrospectively construct their work in relation to organizational restructurings? How do organizational restructurings bring about specific social processes in product development? This working paper focuses on these questions. The overall aim is to develop an understanding of how software product developers construct their work during organizational restructurings. The theoretical frame of reference is based on a social constructionist approach and discourse analysis. This approach offers more or less radical and critical alternatives to mainstream organizational theory. Writings from this perspective attempt to investigate and understand sociocultural processes by which various realities are created. Therefore these studies aim at showing how people participate in constituting the social world (Gergen & Thatchenkery, 1996); knowledge of the world is seen to be constructed between people in daily interaction, in which language plays a central role. This means that interaction, especially the ways of talking and writing about product development during organizational restructurings, become the target of concern. This study consists of 25 in-depth interviews following a pilot study based on 57 semi-structured interviews. In this working paper I analyze 9 in-depth interviews. The interviews were conducted in eight IT firms. The analysis explores how discourses are constructed and function, as well as the consequences that follow from different discourses. The analysis shows that even though the product developers have experienced many organizational restructurings, some of which have been far-reaching, their accounts build strongly on a stability discourse. According to this discourse product development is, perhaps surprisingly, not influenced to a great extent by organizational restructurings. This does not mean that product development is static. According to the social constructionist approach, product development is constantly being reproduced and maintained in ongoing processes. In other words stable effects are also ongoing achievements and these are of particular interest in this study. The product developers maintain rather than change the product development through ongoing processes of construction, even when they experience continuous extensive organizational restructurings. The discourse of stability exists alongside other discourses, some which contradict each other. Together they direct product development and generate meanings. The product developers consequently take an active role in the construction of their work during organizational restructurings. When doing this they also negotiate credible positions for themselves

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The first line medication for mild to moderate Alzheimer s disease (AD) is based on cholinesterase inhibitors which prolong the effect of the neurotransmitter acetylcholine in cholinergic nerve synapses which relieves the symptoms of the disease. Implications of cholinesterases involvement in disease modifying processes has increased interest in this research area. The drug discovery and development process is a long and expensive process that takes on average 13.5 years and costs approximately 0.9 billion US dollars. Drug attritions in the clinical phases are common due to several reasons, e.g., poor bioavailability of compounds leading to low efficacy or toxic effects. Thus, improvements in the early drug discovery process are needed to create highly potent non-toxic compounds with predicted drug-like properties. Nature has been a good source for the discovery of new medicines accounting for around half of the new drugs approved to market during the last three decades. These compounds are direct isolates from the nature, their synthetic derivatives or natural mimics. Synthetic chemistry is an alternative way to produce compounds for drug discovery purposes. Both sources have pros and cons. The screening of new bioactive compounds in vitro is based on assaying compound libraries against targets. Assay set-up has to be adapted and validated for each screen to produce high quality data. Depending on the size of the library, miniaturization and automation are often requirements to reduce solvent and compound amounts and fasten the process. In this contribution, natural extract, natural pure compound and synthetic compound libraries were assessed as sources for new bioactive compounds. The libraries were screened primarily for acetylcholinesterase inhibitory effect and secondarily for butyrylcholinesterase inhibitory effect. To be able to screen the libraries, two assays were evaluated as screening tools and adapted to be compatible with special features of each library. The assays were validated to create high quality data. Cholinesterase inhibitors with various potencies and selectivity were found in natural product and synthetic compound libraries which indicates that the two sources complement each other. It is acknowledged that natural compounds differ structurally from compounds in synthetic compound libraries which further support the view of complementation especially if a high diversity of structures is the criterion for selection of compounds in a library.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Many Finnish IT companies have gone through numerous organizational changes over the past decades. This book draws attention to how stability may be central to software product development experts and IT workers more generally, who continuously have to cope with such change in their workplaces. It does so by analyzing and theorizing change and stability as intertwined and co-existent, thus throwing light on how it is possible that, for example, even if ‘the walls fall down the blokes just code’ and maintain a sense of stability in their daily work. Rather than reproducing the picture of software product development as exciting cutting edge activities and organizational change as dramatic episodes, the study takes the reader beyond the myths surrounding these phenomena to the mundane practices, routines and organizings in product development during organizational change. An analysis of these ordinary practices offers insights into how software product development experts actively engage in constructing stability during organizational change through a variety of practices, including solidarity, homosociality, close relations to products, instrumental or functional views on products, preoccupations with certain tasks and humble obedience. Consequently, the study shows that it may be more appropriate to talk about varieties of stability, characterized by a multitude of practices of stabilizing rather than states of stagnation. Looking at different practices of stability in depth shows the creation of software as an arena for micro-politics, power relations and increasing pressures for order and formalization. The thesis gives particular attention to power relations and processes of positioning following organizational change: how social actors come to understand themselves in the context of ongoing organizational change, how they comply with and/or contest dominant meanings, how they identify and dis-identify with formalization, and how power relations often are reproduced despite dis-identification. Related to processes of positioning, the reader is also given a glimpse into what being at work in a male-dominated and relatively homogeneous work environment looks like. It shows how the strong presence of men or “blokes” of a particular age and education seems to become invisible in workplace talk that appears ‘non-conscious’ of gender.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Merkittävä osa alkuperäislääkevalmistajien tutkimus- ja tuotekehityskuluista näyttää olevan suunnattu olemassa olevien lääkkeiden kehittämiseen. Tämä voi oletettavasti johtaa kiinnostaviin formulaatiokehitysstrategioihin. Tutkimuksen tarkoituksena oli selvittää, voidaanko farmaseuttisen tuotekehityksen trendejä havaita myönnettyjen myyntilupien perusteella. Tutkimuksen mielenkiinnon kohteena olivat myös suurimpien lääkeyritysten käyttämät elinkaaren hallinnan keinot, joilla suojataan myyvimpiä tuotteita geneeriseltä kilpailulta ja varmistetaan markkinaosuus. Tutkimuksen painopiste oli kiinteissä oraalisissa lääkevalmisteissa. Laadullisten ja määrällisten menetelmien yhdistelmää käytettiin laajan näkökulman saamiseksi tutkittavaan aiheeseen. Suomalaisten myyntilupaviranomaisten haastatteluja käytettiin keräämään taustatietoa tutkimuksen määrällistä osaa varten. Määrällinen osa koostui myyntilupatietokannoista, jotka käsittivät kaikkien menettelyjen kautta Suomessa myönnetyt myyntiluvat, keskitetyn menettelyn kautta EU:ssa myönnetyt myyntiluvat ja maailman kymmenen suurinta lääkeyritystä USA:ssa. Tutkimustulosten perusteella rinnakkaislääkkeiden määrässä tapahtui merkittävä nousu Suomessa kaikkien menettelyjen kautta myönnetyissä myyntiluvissa ja EU:ssa keskitetyn menettelyn kautta myönnetyissä myyntiluvissa vuosina 2000-2010. Tämä muutos saattaa ainakin osaksi johtua lainsäädännöllisistä muutoksista, joilla luotiin kannustimia rinnakkaislääkkeiden käyttöön ja valmistukseen, kuten lääkevaihto ja viitehintajärjestelmä. USA:n tiedot osoittivat suurten lääkevalmistajien kiinnostuksen elinkaaren hallintaan: suurin osa maailman kymmenelle suurimmalle lääkeyritykselle myönnetyistä myyntiluvista vuosina 2005-2010 oli tähän tarkoitukseen. Elinkaaren hallinnan suhde uusiin lääkeaineisiin oli lähes 4:1. Kiinteä oraalinen lääkemuoto on kiistatta kaikista suosituin tapa annostella lääke, minkä vahvistivat sekä arvioijien haastattelut että myyntilupatiedot. Kiinteiden oraalisten rooli oli entistäkin korostuneempi rinnakkaislääkkeiden kohdalla. Kun innovatiivisuutta mitattiin epätyypillisten annosmuotojen määrällä, USA:n tiedot kiinteistä oraalisista lääkemuodoista osoittivat vahvaa innovatiivisuutta Suomen ja EU:n tietoihin verrattuna. Tämä saattaa heijastaa suurten lääkeyritysten innovatiivista tuotevalikoimaa. Epätyypillisten kiinteiden oraalisten annosmuotojen osuus oli huomattavasti pienempi rinnakkaislääkkeissä kuin alkuperäislääkkeissä kaikilla alueilla. Elinkaaren hallinnassa käytetyimmät strategiat olivat uusi formulaatio, uusi vahvuus ja uusi yhdistelmä olemassa olevasta valmisteesta. Kiinteiden oraalisten lääkemuotojen osalta kaksi kolmasosaa uusista elinkaaren hallinnan formulaatioista oli säädellysti vapauttavia valmisteita. Elinkaaren hallinta on olennainen osa suurten lääkeyritysten liiketoimintastrategiaa, ja sen tärkeyttä havainnollistettiin Coreg-tablettien tapausesimerkillä.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Generation of raw materials for dry powder inhalers by different size reduction methods can be expected to influence physical and chemical properties of the powders. This can cause differences in particle size, size distribution, shape, crystalline properties, surface texture and energy. These physical properties of powders influence the behaviour of particles before and after inhalation. Materials with an amorphous surface have different surface energy compared to materials with crystalline surface. This can affect the adhesion and cohesion of particles. Changes in the surface nature of the drug particles results in a change in product performance. By stabilization of the raw materials the amorphous surfaces are converted into crystalline surfaces. The primary aim of the study was to investigate the influence of the surface properties of the inhalation particles on the quality of the product. The quality of the inhalation product is evaluated by measuring the fine particle dose (FPD). FDP is the total dose of particles with aerodynamic diameters smaller than 5,0 μm. The secondary aim of this study was to achieve the target level of the FPD and the stability of the FPD. This study was also used to evaluate the importance of the stabilization of the inhalation powders. The study included manufacturing and analysing drug substance 200 μg/dose inhalation powder batches using non-stabilized or stabilized raw materials. The inhaler formulation consisted of micronized drug substance, lactose <100μm and micronized lactose <10μm. The inhaler device was Easyhaler®. Stabilization of the raw materials was done in different relative humidity, temperature and time. Surface properties of the raw materials were studied by dynamic vapour sorption, scanning electron microscopy and three-point nitrogen adsorption technique. Particle size was studied by laser diffraction particle size analyzer. Aerodynamic particle size distribution from inhalers was measured by new generation impactor. Stabilization of all three raw materials was successful. A clear difference between nonstabilized and stabilized raw materials was achieved for drug substance and lactose <10μm. However for lactose <100μm the difference wasn’t as clear as wanted. The surface of the non-stabilized drug substance was more irregular and the particles had more roughness on the surface compared to the stabilized drug substances particles surface. The surface of the stabilized drug particles was more regular and smoother than non-stabilized. Even though a good difference between stabilized and non-stabilized raw materials was achieved, a clear evidence of the effect of the surface properties of the inhalation particles on the quality of the product was not observed. Stabilization of the raw materials didn’t lead to a higher FPD. Possible explanations for the unexpected result might be too rough conditions in the stabilization of the drug substance or smaller than wanted difference in the degree of stabilization of the main component of the product <100μm. Despite positive effects on the quality of the product were not seen there appears to be some evidence that stabilized drug substance results in smaller particle size of dry powder inhalers.