On SAT representations of XOR constraints

We study the representation of systems S of linear equations over the two-element field (aka xor- or parity-constraints) via conjunctive normal forms F (boolean clause-sets). First we consider the problem of finding an "arc-consistent" representation ("AC"), meaning that unit-clause propagation will fix all forced assignments for all possible instantiations of the xor-variables. Our main negative result is that there is no polysize AC-representation in general. On the positive side we show that finding such an AC-representation is fixed-parameter tractable (fpt) in the number of equations. Then we turn to a stronger criterion of representation, namely propagation completeness ("PC") --- while AC only covers the variables of S, now all the variables in F (the variables in S plus auxiliary variables) are considered for PC. We show that the standard translation actually yields a PC representation for one equation, but fails so for two equations (in fact arbitrarily badly). We show that with a more intelligent translation we can also easily compute a translation to PC for two equations. We conjecture that computing a representation in PC is fpt in the number of equations.Comment: 39 pages; 2nd v. improved handling of acyclic systems, free-standing proof of the transformation from AC-representations to monotone circuits, improved wording and literature review; 3rd v. updated literature, strengthened treatment of monotonisation, improved discussions; 4th v. update of literature, discussions and formulations, more details and examples; conference v. to appear LATA 201

Regular albuterol or nedocromil sodium — effects on airway subepithelial tenascin in asthma

AbstractBoth albuterol and nedocromil sodium have been recognized to possess certain anti-inflammatory properties. However, there are no data on the impact of these drugs on the pathophysiology of the bronchial extracellular matrix in asthma characterized by enhanced tenascin (Tn) expression, known to occur proportional to the severity of asthma. This paper reports data from a morphometric study on the effects of regular treatment with inhaled albuterol or nedocromil sodium on the extent of bronchial subepithelial deposition of Tn, collagen types III, IV, and VII and mucosal infiltration with macrophages.Thirty-two patients (14 women) with chronic asthma, aged 38·7 years (median) with a median forced expiratory volume in 1 sec (FEV1) of 74·4% predicted, were selected to undergo fibre-optic bronchoscopy with bronchial biopsies before and after 12 weeks of treatment with either inhaled albuterol 0·2 mg or nedocromil sodium 4 mg four times daily according to a double-blind protocol. Cryostat sections of the biopsy specimens were studied by indirect immunostaining techniques using monoclonal antibodies and computer-assisted quantitative image analysis.Albuterol treatment significantly reduced the median thickness of subepithelial Tn expression from 9·7 to 6·3 μm (P=0·023) and macrophage numbers in the epithelium (P=0·034), lamina propria (P=0·039) and entire mucosa (P=0·033), whereas nedocromil sodium had no effect. Expression of the collagen types was not affected by either treatment. There was no identifiable statistical difference between the two treatments for any of the outcome variables measured. Nevertheless, the results demonstrate that even a short-acting β2-agonist may exert anti-inflammatory potential sufficient to interfere with the basic mechanisms of asthma as shown by reduction of subepithelial Tn content and mucosal macrophage count

Nuorisotoimen organisaatiomuutos: case Pieksämäki

Tämän kehittämistyön aiheena on nuorisotoimen organisaatiomuutos Pieksämäellä. Tavoitteena oli tuottaa konkreettinen organisaatiomalli miten nuorisotyö asemoituu sivistystoimeen. Kehittämisprosessin alkuvaiheessa nuorisotoimi kuului vapaa-aikatoimen organisaatioon ja oli vuoden 2013 alusta siirtymässä sivistystoimen organisaatioon tavoitteenaan tiivistää monialaista yhteistyötä koulutoimen kanssa merkittävästi. Tässä opinnäytetyössä kuvaamme muutosprosessia nuorisotoimen näkökulmasta Muutosjohtaminen oli tapa jolla muutosta Pieksämäellä käsiteltiin ja vietiin eteenpäin sekä organisaatio- että yksilötasolla. Muutosjohtaminen edellytti huolellista suunnittelua ja tilanneherkkää toteutusta sekä ennen kaikkea muutokseen vaikutuspiirissä olevien henkilöiden kuulemista ja osallistumista. Yksi muutoksen läpiviemisen keskeisiä menestystekijöitä organisaatiossa oli myös pedagoginen johtajuus. Muutoksen suunnittelussa käytimme apuna SWOT – analyysia ja kehittämiskeskustelujen kautta kartoitimme nuorisotyöntekijöiden pedagogista osaamista. Pieksämäen nuorisotoimen kehittämistyön teoreettinen tausta pohjaa vahvasti lapsi- ja nuorisopolitiikan kehittämisohjelman 2012 - 2015 strategisiin tavoitteisiin ja toimenpiteisiin. Kehittämistyön avain tavoitteet lähtevät lapsi - ja nuorisopoliittisen kehittämisohjelman strategioista kahdeksan ja yhdeksän. Strategiassa kahdeksan tuodaan esiin ennaltaehkäisyn tärkeys lasten ja nuorten hyvinvoinnin ylläpidossa ja strategia yhdeksän edellyttää yhteistyön voimistamista lasten, nuorten ja perheiden palveluiden koordinoinnissa ja toimijoiden osaamisen vahvistamista. Nämä tavoitteet sekä paikallinen lasten ja nuorten hyvinvointisuunnitelmatyö antoivat vahvan pohjan uuden organisaatiomallin luomiseen Pieksämäellä.The subject of this thesis is the organizational change of youth services in Pieksämäki. The objective of this development project is a specific model as to how youth work is positioned in the Education services. At the beginning of the development process youth services were moving from the leisure time board to the education board. The aim was to intensify the cross-sectional co-operation with the educational organization. In this thesis we describe the process of change from the perspective of youth services Management of change was the way the change in Pieksämäki was discussed and taken forward at the organizational as well as at the individual level. Change management careful planning and sensitive implementation, and above all, the consultation and participation of the people who were affected by the change. One of the main success factors of change in the organization was the pedagogical leadership. A SWOT - analysis was used as an aid in the planning of the change and through development discussion the youth workers’ pedagogical competences were studied. The theoretical background of this development work is strongly based on the strategic objectives and measures of the child and youth development program 2012 - 2015. The key objective of the development work comes from a child - and youth policy development strategies, eight and nine. Strategy eight highlights the importance of preventive measures for children’s and young people's well-being, strategy nine requires closer cooperation, coordination and improvement of workers' skills in the services for the children, young people and families. These objectives provided a strong foundation for the creation of a new organizational model in Pieksämäki

The Mechanism of Electro-Reduction of Chromate in Molten LiCl-KCl

When chromate ion is electro-reduced in molten LiCl- KCl in the presence of Mg (II), Zn (II) or Ni (II), the product is typically of composition LixMyCr04 , in which X + 2 Y = 5. Variations in composition accompany variations is experimental conditions, except in the case of Zn(II), for which X = 1 and Y = · 2. With Co (II), the product is either LixCoyCr04 or Co2Cr04 or a mixture of the two, depending upon the conditions. A mechanism involving a first two-electron reduction followed by a competition between further one-electron reduction and an internal chemical redox reaction accounts -satisfactorily for the variation of product with changes in experimental conditions

The Mechanism of Electro-Reduction of Chromate in Molten LiCl-KCl

When chromate ion is electro-reduced in molten LiCl- KCl in the presence of Mg (II), Zn (II) or Ni (II), the product is typically of composition LixMyCr04 , in which X + 2 Y = 5. Variations in composition accompany variations is experimental conditions, except in the case of Zn(II), for which X = 1 and Y = · 2. With Co (II), the product is either LixCoyCr04 or Co2Cr04 or a mixture of the two, depending upon the conditions. A mechanism involving a first two-electron reduction followed by a competition between further one-electron reduction and an internal chemical redox reaction accounts -satisfactorily for the variation of product with changes in experimental conditions

Evolution of kinklike fluctuations associated with ion pickup within reconnection outflows in the Earth's magnetotail

Magnetic reconnection (MR) in Earth's magnetotail is usually followed by a systemwide redistribution of explosively released kinetic and thermal energy. Recently, multispacecraft observations from the THEMIS mission were used to study localized explosions associated with MR in the magnetotail so as to understand subsequent Earthward propagation of MR outbursts during substorms. Here we investigate plasma and magnetic field fluctuations/structures associated with MR exhaust and ion-ion kink mode instability during a well documented MR event. Generation, evolution and fading of kinklike oscillations are followed over a distance of 70 000 km from the reconnection site in the midmagnetotail to the more dipolar region near the Earth. We have found that the kink oscillations driven by different ion populations within the outflow region can be at least 25 000 km from the reconnection site.Comment: 11 pages, 4 figure

Local-scale patterns of genetic variability, outcrossing, and spatial structure in natural stands of Arabidopsis thaliana

As Arabidopsis thaliana is increasingly employed in evolutionary and ecological studies, it is essential to understand patterns of natural genetic variation and the forces that shape them. Previous work focusing mostly on global and regional scales has demonstrated the importance of historical events such as long-distance migration and colonization. Far less is known about the role of contemporary factors or environmental heterogeneity in generating diversity patterns at local scales. We sampled 1,005 individuals from 77 closely spaced stands in diverse settings around Tübingen, Germany. A set of 436 SNP markers was used to characterize genome-wide patterns of relatedness and recombination. Neighboring genotypes often shared mosaic blocks of alternating marker identity and divergence. We detected recent outcrossing as well as stretches of residual heterozygosity in largely homozygous recombinants. As has been observed for several other selfing species, there was considerable heterogeneity among sites in diversity and outcrossing, with rural stands exhibiting greater diversity and heterozygosity than urban stands. Fine-scale spatial structure was evident as well. Within stands, spatial structure correlated negatively with observed heterozygosity, suggesting that the high homozygosity of natural A. thaliana may be partially attributable to nearest-neighbor mating of related individuals. The large number of markers and extensive local sampling employed here afforded unusual power to characterize local genetic patterns. Contemporary processes such as ongoing outcrossing play an important role in determining distribution of genetic diversity at this scale. Local "outcrossing hotspots" appear to reshuffle genetic information at surprising rates, while other stands contribute comparatively little. Our findings have important implications for sampling and interpreting diversity among A. thaliana accessions.Financial support came from an NIH Ruth Kirschstein NRSA Postdoctoral Fellowship (KB), a Human Frontiers Science Program Postdoctoral Fellowship (RAL), grants DFG ERA-PG ARelatives and FP6 IP AGRON-OMICS (contract LSHG-CT-2006-037704), from a Gottfried Wilhelm Leibniz Award of the DFG, and the Max Planck Society (DW)

Global and local disturbances in the magnetotail during reconnection

We examine Cluster observations of a reconnection event at <I>x</I><sub>GSM</sub>=−15.7 <I>R<sub>E</sub></I> in the magnetotail on 11 October 2001, when Cluster recorded the current sheet for an extended period including the entire duration of the reconnection event. The onset of reconnection is associated with a sudden orientation change of the ambient magnetic field, which is also observed simultaneously by Goes-8 at geostationary orbit. Current sheet oscillations are observed both before reconnection and during it. The speed of the flapping motions is found to increase when the current sheet undergoes the transition from quiet to active state, as suggested by an earlier statistical result and now confirmed within one single event. Within the diffusion region both the tailward and earthward parts of the quadrupolar magnetic Hall structure are recorded as an x-line passes Cluster. We report the first observations of the Hall structure conforming to the kinks in the current sheet. This results in relatively strong fluctuations in <I>B<sub>z</sub></I>, which are shown to be the Hall signature tilted in the <I>yz</I> plane with the current sheet

Supermagnetosonic jets behind a collisionless quasi-parallel shock

The downstream region of a collisionless quasi-parallel shock is structured containing bulk flows with high kinetic energy density from a previously unidentified source. We present Cluster multi-spacecraft measurements of this type of supermagnetosonic jet as well as of a weak secondary shock front within the sheath, that allow us to propose the following generation mechanism for the jets: The local curvature variations inherent to quasi-parallel shocks can create fast, deflected jets accompanied by density variations in the downstream region. If the speed of the jet is super(magneto)sonic in the reference frame of the obstacle, a second shock front forms in the sheath closer to the obstacle. Our results can be applied to collisionless quasi-parallel shocks in many plasma environments.Comment: accepted to Phys. Rev. Lett. (Nov 5, 2009

The universal functorial equivariant Lefschetz invariant

We introduce the universal functorial equivariant Lefschetz invariant for endomorphisms of finite proper G-CW-complexes, where G is a discrete group. We use K_0 of the category of "phi-endomorphisms of finitely generated free RPi(G,X)-modules". We derive results about fixed points of equivariant endomorphisms of cocompact proper smooth G-manifolds.Comment: 33 pages; shortened version of the author's PhD thesis, supervised by Wolfgang Lueck, Westfaelische Wilhelms-Universitaet Muenster, 200