The Power of Non-Determinism in Higher-Order Implicit Complexity

We investigate the power of non-determinism in purely functional programming languages with higher-order types. Specifically, we consider cons-free programs of varying data orders, equipped with explicit non-deterministic choice. Cons-freeness roughly means that data constructors cannot occur in function bodies and all manipulation of storage space thus has to happen indirectly using the call stack. While cons-free programs have previously been used by several authors to characterise complexity classes, the work on non-deterministic programs has almost exclusively considered programs of data order 0. Previous work has shown that adding explicit non-determinism to cons-free programs taking data of order 0 does not increase expressivity; we prove that this - dramatically - is not the case for higher data orders: adding non-determinism to programs with data order at least 1 allows for a characterisation of the entire class of elementary-time decidable sets. Finally we show how, even with non-deterministic choice, the original hierarchy of characterisations is restored by imposing different restrictions.Comment: pre-edition version of a paper accepted for publication at ESOP'1

Polymer-based microfluidic device for measuring membrane protein activities

Functional assays of membrane proteins are becoming increasingly important, both in research and drug discovery applications. The majority of current assays use the patch-clamp technology to measure the activity of ion channels which are over-expressed in cells. In future, in vitro assay systems will be available, which use reconstituted membrane proteins in free-standing lipid bilayers suspended in nano- or micrometer-sized pores. Such functional assays require (1) expression, purification and reconstitution of the membrane protein of interest, (2) a reliable method for lipid bilayer formation and membrane protein integration, and (3) a sensitive detection system. For practical applications, especially for automation, the reliable and controllable transport of fluids is essential. In order to achieve a stable free-standing lipid bilayer, a pore diameter in the micro- to nanometer range is essential. Novel microfluidic devices were developed by bonding a thick (300μm) polyether ether ketone foil, bearing a channel structure, to a thin (12μm) foil with a micropore of about 10μm diameter and then utilized for the formation of stable, free-standing lipid bilayers within the pore. A bacterial voltage-gated potassium channel is integrated therein by fusion and the ion channel activity detected by voltage clam

Uptake and distribution of ions reveal contrasting tolerance mechanisms for soil and water salinity in okra (Abelmoschus esculentus) and tomato (Solanum esculentum)

Okra and tomatoes are major vegetable crops commonly grown under irrigation, and understanding whether they respond to salinity by withstanding (tissue tolerance) or avoiding (salt exclusion) accumulation of salt in the shoots will assist with management for optimizing yield under declining soil and water resources. Both crops were grown in non-saline (0.0 dS/m) and saline (3.0 dS/m) loamy sand and drip irrigated with water of 0.0, 1.2 or 2.4 dS/m. Differences in the growth and yields of the two crops under saline conditions were associated with uptake and distribution of cations, especially Na. The tomato employed tissue tolerance mechanism in response to salinity and produced fruits even when shoot/root Na concentration was >3.0; concentrations of Na in tomato tissues was in the order shoots > roots ≈ fruits. Okra was sensitive to shoot Na such that a shoot/root Na concentration as low as 0.13 reduced yield by as much as 35%; this crop employed salt exclusion mechanism and minimized shoot accumulation of Na, which was distributed in the order fruits > roots > shoots.Root and shoot concentrations of Na, P and S were correlated with flower abortion and negatively correlated with yield and yield components in both crops. Fresh fruit produced on the saline soil were reduced by 19% in tomato compared with 59% in okra, relative to yields on non-saline soil. Water salinity reduced fresh fruit yields in the tomato by as much as 36% with every unit (dS/m) rise in water salinity compared with 27% in okra. Soil salinity significantly reduced water-use by 6% in tomatoes and 29% in okra, but had no impact on water use efficiency (WUE) that averaged 3.9 g of fresh fruits/L for tomatoes and 1.75 g/L for okra. Every 1.0 dS/m rise in water salinity reduced water-use by 0.33 L in okra and 3.31 L in tomatoes, and reduced WUE by 2.61 g/L in tomatoes and 0.53 g/L in okra. Soil salinity explained <5% of the variance in yields in tomatoes and 10–20% in okra, while water salinity explained 48–68% of the variance in tomatoes and about 40% in okra. We conclude that (1) water salinity was more injurious to yield in both crops than soil salinity, and (2) yield losses due to salinity can be minimized through frequent leaching of soil salt under okra and increased irrigation intervals in tomatoes

Integration of measurements and model simulations to characterize Eyjafjallajökull volcanic aerosols over south-eastern Italy

Abstract. Volcanic aerosols resulting from the Eyjafjallajökull eruption were detected in south-eastern Italy from 20 to 22 April 2010, at a distance of approximately 4000 km from the volcano, and have been characterized by lidar, sun/sky photometer, and surface in-situ measurements. Volcanic particles added to the pre-existing aerosol load and measurement data allow quantifying the impact of volcanic particles on the aerosol vertical distribution, lidar ratios, the aerosol size distribution, and the ground-level particulate-matter concentrations. Lidar measurements reveal that backscatter coefficients by volcanic particles were about one order of magnitude smaller over south-eastern Italy than over Central Europe. Mean lidar ratios at 355 nm were equal to 64 ± 5 sr inside the volcanic aerosol layer and were characterized by smaller values (47 ± 2 sr) in the underlying layer on 20 April, 19:30 UTC. Lidar ratios and their dependence with the height reduced in the following days, mainly because of the variability of the volcanic particle contributions. Size distributions from sun/sky photometer measurements reveal the presence of volcanic particles with radii r > 0.5 μm on 21 April and that the contribution of coarse volcanic particles increased from 20 to 22 April. The aerosol fine mode fraction from sun/sky photometer measurements varied between values of 0.85 and 0.94 on 20 April and decreased to values between 0.25 and 0.82 on 22 April. Surface measurements of particle size distributions were in good accordance with column averaged particle size distributions from sun/sky photometer measurements. PM1/PM2.5 mass concentration ratios of 0.69, 0.66, and 0.60 on 20, 21, and 22 April, respectively, support the increase of super-micron particles at ground. Measurements from the Regional Air Quality Agency show that PM10 mass concentrations on 20, 21, and 22 April 2010 were enhanced in the entire Apulia Region. More specifically, PM10 mass concentrations have on average increased over Apulia Region 22%, 50%, and 28% on 20, 21, and 22 April, respectively, compared to values on 19 April. Finally, the comparison of measurement data with numerical simulations by the FLEXPART dispersion model demonstrates the ability of FLEXPART to model the advection of the volcanic ash over the 4000 km from the Eyjafjallajökull volcano to Southern Italy

Some Weed Species Affecting Soybean Nodulation And Nodule Function

Experiments aimed at examining the effect of aqueous extracts of three weed species on nodulation and nodule function of soybean cv. Melrose have been carried out at the Laboratory of Plant Physiology and Biotechnology, Department of Agronomy and Soil Science, University of New England, Australia. Aqueous extracts of fresh weed material (Amaranthus powellii, Cyperus rotundus and Paspalum dilatatum) at the concentration of 10% (w/v) were added to a minus-nitrogen Hoagland\u27s nutrient solution in which the soybean plants were grown with 14 hours day length, day and night temperatures of 28 and 20°C, respectively, light intensity of 790 mmol/m2/s, and the relative humidity of 65%. The plants were kept for three weeks prior to the measurement of activity of nitrogenase enzyme and ammonium content of the root nodules. Results demonstrate that all weed extracts reduced the nodulation and nitrogenase activities (ARA) of soybean cv. Melrose. Amaranth was most inhibitory to nitrogenase enzyme activity. However, amaranth extract was less inhibitory than nutgrass extract in total ammonium content

Cost-effectiveness of cervical cancer screening with primary human papillomavirus testing in Norway

Background: New screening technologies and vaccination against human papillomavirus (HPV), the necessary cause of cervical cancer, may impact optimal approaches to prevent cervical cancer. We evaluated the cost-effectiveness of alternative screening strategies to inform cervical cancer prevention guidelines in Norway. Methods: We leveraged the primary epidemiologic and economic data from Norway to contextualise a simulation model of HPV-induced cervical cancer. The current cytology-only screening was compared with strategies involving cytology at younger ages and primary HPV-based screening at older ages (31/34+ years), an option being actively deliberated by the Norwegian government. We varied the switch-age, screening interval, and triage strategies for women with HPV-positive results. Uncertainty was evaluated in sensitivity analysis. Results: Current cytology-only screening was less effective and more costly than strategies that involve switching to primary HPV testing in older ages. For unvaccinated women, switching at age 34 years to primary HPV testing every 4 years was optimal given the Norwegian cost-effectiveness threshold ($83 000 per year of life saved). For vaccinated women, a 6-year screening interval was cost-effective. When we considered a wider range of strategies, we found that an earlier switch to HPV testing (at age 31 years) may be preferred. Conclusions: Strategies involving a switch to HPV testing for primary screening in older women is expected to be cost-effective compared with current recommendations in Norway

Prevalence of reverse transcriptase and protease mutations associated with antiretroviral drug resistance among drug-naïve HIV-1 infected pregnant women in Kagera and Kilimanjaro regions, Tanzania

<p>Abstract</p> <p>Background</p> <p>Access to antiretroviral drugs for HIV-1 infection has increased in sub-Saharan Africa (SSA) during the past few years. Mutations in the HIV-1 genome are often associated with treatment failure as indicated by viral replication and elevated levels of virus in the blood. Mutations conferring resistance to antiretroviral drugs are based on comparing gene sequences with corresponding consensus sequences of HIV-1 subtype B that represents only 10% of the AIDS pandemic. The HIV pandemic in SSA is characterized by high viral genetic diversity. Before antiretroviral drugs become more widely available, it is important to characterize baseline naturally occurring genetic mutations and polymorphisms associated with antiretroviral drug resistance among circulating HIV-1 subtypes.</p> <p>Methods</p> <p>The prevalence of mutations associated with antiretroviral drug resistance in protease (PR) and reverse transcriptase (RT) regions among antiretroviral treatment-naïve HIV-1 infected pregnant women was investigated in Bukoba (Kagera) and Moshi (Kilimanjaro) municipalities, Tanzania, between September and December 2005. The HIV-1 <it>pol </it>gene was amplified using primers recognizing conserved viral sequences and sequenced employing BigDye chemistry from 100 HIV-1 seropositive treatment-naïve pregnant women and 61 HIV-1 seropositive women who had received a single dose of Nevirapine (sdNVP). Positions 1–350 of the RT and 1–99 of the PR genes were analyzed for mutations based on the Stanford University HIV Drug Resistance Database.</p> <p>Results</p> <p>HIV-1 subtypes A, C, D, CRF10_CD and Unique Recombinant Forms (URF) were detected. Primary mutations associated with NRTI and NNRTI resistance were detected among 3% and 4% of treatment-naïve strains, respectively. Primary mutations associated with NRTI and NNRTI resistance were detected in 1.6% and 11.5% of women who had received sdNVP, respectively. None of the primary mutations associated with PI resistance was found. Polymorphisms detected in RT and PR sequences were mainly mutations that are found in the consensus sequences of non-B subtypes</p> <p>Conclusion</p> <p>Based on the WHO HIV Drug Resistance Research Network Threshold of less than 5%, the baseline prevalence of primary mutations among treatment-naïve HIV-1 infected pregnant women in Kagera and Kilimanjaro regions was low. The significance of HIV-1 subtype B polymorphic positions with respect to antiretroviral resistance identified among the prevalent HIV-1 subtypes is unknown. More studies addressing the correlation between polymorphic mutations, antiretroviral resistance and clinical outcome are warranted in regions where non-B subtypes are prevalent.</p

Multivariate analysis of oestrogen receptor alpha, pS2, metallothionein and CD24 expression in invasive breast cancers

Determination of oestrogen receptor alpha (ER) represents at present the most important predictive factor in breast cancers. Data of ours and of other authors suggest that promising predictive/prognostic factors may also include pS2, metallothionein (MT) and CD24. Present study aimed at determining prognostic and predictive value of immunohistochemical determination of ER, pS2, MT, and CD24 expression in sections originating from 104 patients with breast cancer. An univariate and multivariate analysis was performed. Both univariate and multivariate analyses demonstrated that cytoplasmic-membranous expression of CD24 (CD24c-m) represents a strong unfavourable prognostic factor in the entire group and in most of the subgroups of patients. In several subgroups of the patients also a prognostic value was demonstrated of elevated expression of pS2 and of membranous expression of CD24. Our studies demonstrated that all patients with good prognostic factors (higher ER and pS2 expressions, lower MT expression, CD24c-m negativity) survived total period of observation (103 months). The study documented that cytoplasmic-membranous expression of CD24 represented an extremely strong unfavourable prognostic factor in breast cancer. Examination of the entire panel of the studied proteins permitted to select a group of patients of an exceptionally good prognosis