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

Exposure to glycols and their renal effects in motor servicing workers

Ten car mechanics frequently exposed to glycol-based cooling liquids were followed during a workshift. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were measured. The car mechanics gave urine samples after the workshift and their excretion of ethylene glycol, propylene glycol, oxalic acid, calcium and ammonia was analysed and compared to that of unexposed office workers. Urinary succinate dehydrogenase activity and glycosaminoglycans were also measured in both groups. Airborne ethylene and propylene glycol concentrations in the car mechanics' environment were negligible. Urinary ethylene glycol excretion in exposed workers was significantly higher than that in unexposed workers, but propylene glycol excretion was at the same level as in controls. In the exposed group, the excretion of the end metabolite of ethylene glycol, oxalic acid (47 ± 11 mmol/mol creatinine, mean ± SD, n= 10) differed slightly from that of controls (36 ± 14 mmol/mol creatinine, mean ± SD, n= 10). Urinary excretion of ammonia was higher among exposed workers than office workers. The excretion of calcium did not differ from that of controls. A marginally decreased urinary succinate dehydrogenase activity was found in the exposed men. The excretion of glycosaminoglycans was significantly lower in exposed workers. Therefore, it seems that ethylene glycol is absorbed by skin contact. The internal body burden is associated with oxaluria and increased ammoniagenesis typical of chronic acidosi

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

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

Effects of preventive home visits on older people's use and costs of health care services : A systematic review

Peer reviewe

Preventive home visits to promote the health-related quality of life of home-dwelling older people : Baseline findings and feasibility of a randomized, controlled trial

Background and aims: Studies on multiprofessional preventive home visits to older people are needed. We describe here the baseline findings and feasibility of a randomized controlled study on preventive home visits delivered by a multiprofessional team. Materials and methods: Participants (n = 422) were home-dwelling people who were 75+ years old. They were recruited from the Hyvinkaaa municipal area. They were randomized into intervention and control groups. Participants in the intervention group received three home visits, delivered by a nurse, physiotherapist and social worker. Health-related quality of life (HRQoL), measured by 15D, was used as our primary outcome measurement. Feedback on the intervention was gathered from the participants. Results: The mean age of our participants was 81 years. They scored 0.82 in the 15D HRQoL score, and 65% were female. The findings of both groups were similar in most background variables. The only differences between the groups were that lower proportions of participants in the intervention group had diabetes or used a walker. The professionals delivering the intervention reported that all intervention procedures had been delivered according to plan. Participants who responded to the feedback survey mostly reported having gained new information and were fairly content with the intervention. However, most participants felt the home visits had not improved their health or functioning. Conclusions: We have successfully randomized participants into two study groups in this trial examining the effectiveness of preventive home visits. The intervention seems feasible and has mostly been well received. (C) 2017 Elsevier Masson SAS and European Union Geriatric Medicine Society. All rights reserved.Peer reviewe

The relationship between serum 25-hydroxyvitamin D and parathyroid hormone concentration in assessing vitamin D deficiency in pet rabbits

Background Vitamin D deficiency and related metabolic bone diseases in pet rabbits have been intermittently debated. In human research, the parathyroid hormone concentration in relation to the 25-hydroxyvitamin D concentration is used to determine vitamin D deficiency. Thus, this study aimed to identify the breakpoint in the 25-hydroxyvitamin D concentration indicating a significant change in the parathyroid hormone concentration in 139 pet rabbits. An enzyme immunoassay kit was used for 25-hydroxyvitamin D analysis and the intact parathyroid hormone (PTH 1-84) immunoradiometric assay kit for parathyroid hormone analysis. The mid-tibial cortical bone density was measured using peripheral quantitative computed tomography. A segmented linear regression analysis was performed, with the 25-hydroxyvitamin D concentration as the independent variable, and parathyroid hormone, ionised calcium, total calcium, inorganic phosphorus concentrations and the mid-tibial cortical density as the dependent variables. Results The breakpoint for the parathyroid hormone concentration occurred at a 25(OH)D concentration of 17 ng/mL, whereas the cortical bone density breakpoint occurred at a 25-hydroxyvitamin D concentration of 19 ng/mL. No breakpoints were found for ionised calcium, total calcium or phosphorus. Conclusions These results suggest that a serum 25-hydroxyvitamin D concentration of 17 ng/mL serves as the threshold for vitamin D deficiency in rabbits. Nearly one-third of the rabbits had a serum 25-hydroxyvitamin D concentration below this threshold. Concerns persist regarding the high prevalence of vitamin D deficiency in pet rabbits and the possible health consequences caused by a chronic vitamin D deficiency, including the risk for metabolic bone diseases.Peer reviewe

Vaihto-opiskelijoiden haasteet Oulun yliopistossa

Tiivistelmä. Pro gradun aiheena on vaihto-opiskelijoiden haasteet vaihtovuoden aikana Oulun yliopistossa. Opinnäytetyössäni selvitän, millaisia haasteita vaihto-opiskelijat kokivat vaihtonsa aikana Oulun yliopistossa. Lisäksi selvitän, kuinka Oulun yliopisto voisi vaihto-opiskelijoiden mielestä auttaa tulevia vaihto-opiskelijoita paremmin tulevaisuudessa samanlaisten haasteiden kanssa. Tutkimuksen kohteena olivat luonnollisesti kansainväliset opiskelijat. Opinnäytetyön tarkoituksena on kartoittaa isoimmat yhteiset haasteet vaihto-opiskelijoiden keskuudessa ja tuoda esille mahdollisia parannusideoita. Lisäksi pyrin tuomaan vaihto-opiskelijoiden ääntä paremmin kuuluviin. Tutkimusaineistoni koostuu haastatteluista, jotka suoritettiin joko kasvotusten tai etänä. Etähaastattelut tehtiin joko Zoomin kautta tai kirjallisena. Haastattelujen lisäksi tein osallistuvaa havainnointia Cafe Linguassa, sekä syksyllä 2022, että keväällä 2023 ja Nordic Mythology-kurssin luennolla 11.11.2022. Osallistuvan havainnoinnin tarkoituksena oli päästä puhumaan vaihto-opiskelijoiden kanssa vapaammin. Lisäksi se antoi mahdollisuuden nähdä vaihto-opiskelijoiden keskinäistä kanssakäymistä paremmin. Käytin tutkimukseni tukena myös kirjallisia ja digitaalisia lähteitä. Vaihto-opiskelijat kokivat haasteita ylivoimaisesti eniten sosiaalisten suhteiden muodostamisessa sekä muiden vaihto-opiskelijoiden, että suomalaisten opiskelijoiden kanssa. Suomalaisten opiskelijoiden kanssa suhteiden muodostaminen oli vaikeampaa. Vaihto-opiskelijat kokivat, että yliopisto piti heitä erillään suomalaisista opiskelijoista. Vaihto-opiskelijat kokivat kielimuurin luennoilla myös ongelmalliseksi. Toinen huomattava haaste oli kursseille ilmoittautuminen joko ennen vaihtovuotta tai sen aikana. Vaihto-opiskelijat kokivat Oulun yliopistossa opiskelun pääosin helpoksi ja Oulun yliopiston opiskelutilat saivat paljon kiitosta. Yliopiston ulkopuolella koetut haasteet koskivat suomalaisen yhteiskunnan instituutioita ja niiden kanssa asioimista. Etenkin tunnistautumista vaativat palvelut, kuten postin ja pankin palvelut koettiin vaikeaksi. Pienemmiksi haasteiksi mainittiin valon määrän vähyys ja ruokakaupassa asioiminen. Suomen luonto nähtiin positiivisena asiana. Kotimaasta kaivattiin vain oman kulttuurin ruokaa. Vaihto-opiskelijat toivovat selkeästi eniten tukea sosiaaliseen vuorovaikutukseen. Jotkut haasteet tulosten perusteella ruokkivat toisiaan. Esimerkiksi kielimuuri suomalaisten opiskelijoiden kanssa lisäsi kokemusta suomalaisten opiskelijoiden erillään olosta ja sai vaihto-opiskelijat tukeutumaan toisiinsa. Tukea voitaisiin tarjota enemmän muun muassa opastusten muodossa ja lisäämällä järjestettyjä tapahtumia sekä muiden vaihto-opiskelijoiden, että suomalaisten opiskelijoiden kanssa