An automata characterisation for multiple context-free languages

We introduce tree stack automata as a new class of automata with storage and identify a restricted form of tree stack automata that recognises exactly the multiple context-free languages.Comment: This is an extended version of a paper with the same title accepted at the 20th International Conference on Developments in Language Theory (DLT 2016

Preparation and characterization of activated carbons from albizia saman pod

Activated carbon was prepared from the pods of Albizia saman for the purpose of converting the waste to wealth. The pods were thoroughly washed with water to remove any dirt, air- dried and cut into sizes of 2-4 cm. The prepared pods were then carbonised in a muffle furnace at temperatures of 4000C, 5000C, 6000C ,7000C and 8000C for 30 minutes. The same procedure was repeated for 60, 90, 120 and 150 minutes respectively. Activation was done using impregnationratios of 1:12, 1:6, 1:4, 1:3, and 1:2 respectively of ZnCl2 to carbonised Albizia saman pods by weight. The activated carbon was then dried in an oven at 1050C before crushing for sieve analysis. The following properties of the produced Albizia saman pod activated carbon (ASPAC) were determined: bulk density, carbon yield, surface area and ash, volatile matter and moisture contents. The highest surface area of 1479.29 m2/g was obtained at the optimum impregnation ratio, carbonization time and temperature of 1:6, 60 minutes and 5000C respectively. It was recommended that activated carbon should be prepared from Albizia saman pod with high potential for adsorption of pollutants given the high surface area obtained.Keywords: Albizia saman pod, activated carbon, carbonization, temperature, surface are

Adsorption of cadmium (II) from simulated wastewater using Albizia saman pod activated carbon in fixed bed columns

The possibility of using Albizia saman pod activated carbon (ASPAC) as an adsorbent in fixed down flow adsorption columns to remove Cd (II) from wastewater was investigated for the purpose of converting the waste to a valuable product. The effects of impregnation ratio, particle size, carbon height, pressure head and initial cadmium Cd (II) concentration on the adsorption of Cd (II) from wastewater were investigated. The obtained adsorption data from the experiment was then fitted into the Hutchin’s bed depth service time (BDST) model to study the columns performance at 15% and 90% breakthrough concentrations. The BDST model constants were determined. An optimal pressure head of 5 cm, impregnation ratio of 1:6, packing height of 3.5 cm, particle size of 75 μm and initial Cd (II) concentration of 0.029 mg/L were found to be the most effective combination, which removed 100 % of the Cd (II) within a service time of 14 hrs. There was a gradual decrease in the percentage of adsorbed Cd (II) with time; the percentage adsorbed became zero at 44, 56 and 86 hours respectively for 2.5 cm, 3 cm and 3.5 cm carbon heights. The breakthrough curves for Cd (II) adsorption maintained the characteristic S-curve for most dynamic studies. Chi-squared test performed on the developed BDST models revealed the goodness of fit of the models for the prediction of the columns performance at all breakthrough concentrations investigated. The use of ASPAC as adsorbent for the removal of Cd (II) from wastewater in adsorption columns is therefore recommended.Key words: Activated carbon, cadmium (II), fixed bed columns, Albizia saman pod, wastewater

Lube Oil Recycling: Environmental and Economic Implications

This study presents a practical investigation on the reuse of spent lubricating oil as its indiscriminate disposal by the various users daily constitutes a serious pollution problem in the environment. In carrying out this work, samples of various used lubricating oil collected at different locations were analyzed for their physical and chemical composition, to ascertain their suitability for use as fuel in the cement factory. The examined parameters gave average values of 9.4686 kcal/kg, 96 oC, 18.48, 24 oC and 7834.5 kg/m3 for caloric value, flash point, viscosity, pour point and ash content respectively. The results were compared with those of low fuel oil, used in the cement factories. Consequently, a trial burn was conducted which gave mean values of 133.7 mg/m3, 1.7 ppm, 112.3 mg/m3, ﹤25.0 mg/m3, 20.0 mg/m3, ﹤0.1 mg/m3, ﹤6.8 mg/m3 and 371.2 ppm for SPM, CO, THC, SO3, NO3, H2S, NH3 and CO3 respectively. The results obtained clearly showed that the used lubricating oil has chemical composition, calorific value and other physical properties that are comparable to those of low pour fuel oil. The results obtained from the trial burn conducted in the various cement factories, reveal that, the use of used lubricating oil as fuel in cement factories is environmental friendly and economically viable technique of disposing used lubricating oil

Effet d’un système agroforestier à karité (Vitellaria paradoxa c.f. gaertn) sur le sol et le potentiel de production du maïs (Zea maize) en zone Soudanienne du Bénin

L’effet de cinq classes de diamètre du houppier du karité sur les paramètres agronomiques a été étudié en comparant les zones sous houppier et hors houppier en zone soudanienne du Bénin. L’humiditépondérale et la température du sol et les rendements grains et paille du maïs ont été mesurés. La présence des arbres de karité a eu une influence significativement (P< 0,01 à P< 0,001) positive sur l’humidité pondérale et la température du sol de façon croissante avec la largeur du houppier. Les teneurs du sol en C-organique, Ntotal et Ca2+ échangeable sont élevées sous houppier comparativement à la zone hors houppier. Cependant, les rendements sous houppier sont significativement (P< 0,05) faibles comparativement à la zone hors houppier. Les classes de diamètre du houppier n’ont pas influé significativement la production de grains et de paille du maïs. Les rendements grain et paille sous houppier sont réduits respectivement de 46,6% et de 32,8% comparativement à la zone hors houppier. On note une influence positive du système agroforestier à karitésur l’humidité pondérale, la température du sol, le carbone organique et l’azote total, mais un effet négatif est notésur les paramètres de rendement du maïs.Mots clés: Parc à karité, agroforesterie traditionnelle, fertilité du sol, houppier, zone soudanienne

Using Borehole Logging and Electron Backscatter Diffraction to Orient an Ice Core from Upper Fremont Glacier, Wyoming, USA

While glacier fabric reflects the accumulated strain, detailed azimuthal information is required to link the microstructure to the flow, and this is not easily gathered at depth. Borehole logging provides a way to obtain a log of azimuthal orientation of tilted stratigraphic features that can be used to orient the core with respect to glacier flow. We demonstrate this using acoustic borehole logs and the ice core from a 162 m borehole in Upper Fremont Glacier, Wind River Range, Wyoming, USA. We measured the dip of tilted dust and bubble layers in the actual ice core, identified them on the borehole log, then used their strike to orient the core sections containing them. We examined the crystal orientation fabric of our samples, using electron backscatter diffraction in a scanning electron microscope. When we compared the orientation of the tilted layers in some samples with the fabric, we found that the normal to the foliation and the c-axes maxima both pointed in the direction of maximum shear stress. This illustrates the usefulness of borehole logs for orienting ice cores after removal from the borehole, and for developing a better understanding of fabric development

Editor's Choice - Treatment of Aortic Prosthesis Infections by Graft Removal and In Situ Replacement with Autologous Femoral Veins and Fascial Strengthening

Introduction: Aortic prosthetic graft infection (AGI) is a major challenge in vascular surgery. Eradicating the. infection requires prosthetic material removal, debridement, and lower limb revascularization. For the past 15 years, we have used femoral veins for aorto-iliac reconstruction and tensor fascia lata to strengthen the upper anastomosis. Objective: The purpose of this single institution retrospective study is to present results regarding in situ replacement of infected aortic grafts with autologous femoral veins (FVs). Methods: From October 2000 to March 2013, patients treated for AGI with graft removal and autologous FV reconstruction at Helsinki University Hospital were included. Primary outcome measures were 30 day mortality, long-term treatment related mortality, and re-infection rate. Secondary outcome measures were long-term all cause mortality and event free survival (graft rupture, re-intervention, major amputation). Results: During a 13 year period 55 patients (42 male, 13 female) were operated on using a venous neo-aorto-iliac system for AGI. The mean follow up was 32 months (1-157 months). The 30 day mortality rate was 9% (5) and overall treatment related mortality 18% (10). All cause mortality during follow up was 22 (40%) and overall Kaplan-Meier survival was 90.7% at 30 days, 81.5% at 1 year, and 59.3% at 5 years. Graft rupture occurred in three (5%) cases, two of which were caused by graft re-infection. (4%). Four patients required major amputation, one of them on arrival and three (5%) during the post-operative period. Nine (16%) patients needed interventions for the vein graft, and two graft limbs occluded during follow up. Conclusion: In situ reconstruction for aortic graft infection with autologous FV presents acceptable rates of morbidity and mortality, and remains the treatment of choice for AGI at Helsinki University Hospital. (C) 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Normatiivisen etiikan teoriat yläkoulun elämänkatsomustiedon oppikirjoissa

Tiivistelmä. Elämänkatsomustiedon oppiaineessa hyvän elämän tarkastelu muodostaa yhden keskeisistä aihekokonaisuuksista. Oppilaan omaa eettistä kasvua ja pohdintaa pyritään tukemaan etiikan teorioihin nojaten. Normatiivisen etiikan teoriat tarjoavat vaihtoehtoja sille, miten ihmisen tulisi toimia hyvää elämää tarkasteltaessa. Tutkielman teoreettinen viitekehys koostui kolmesta normatiivisen etiikan teoriasta: hyve-etiikasta (teleologia), seurausetiikasta (konsekventialismi) ja velvollisuusetiikasta (deontologia). Tutkimuksen tarkoituksena oli löytää oppikirjojen teksteistä normatiivisen etiikan teorioihin viittaavat tekstit ja tarkastella miten teorioita on käytetty oppikirjojen teksteissä. Motivaatio tutkimukselle on sidoksissa elämänkatsomustiedon oppiaineen kehittämistarpeisiin. Tutkimuskysymyksiä tutkielmassa oli kaksi: Miten normatiivisen etiikan teorioiden käyttö jakaantuu oppikirjoissa? Miten eksplisiittisyys ja implisiittisyys rakentavat oppikirjojen normatiivisen etiikan sisällöt? Aineistona tutkielmassa oli neljä yläkoulun elämänkatsomustietoon tarkoitettua oppikirjaa. Tutkielma toteutettiin kvalitatiivisena tutkimuksena. Aineistoa analysoitiin teorialähtöisen sisällönanalyysin keinoin. Oppikirjojen tekstit käytiin läpi huolellisesti. Aineistoa klusteroitiin ja redusoitiin normatiivisen etiikan teorioiden viitekehyksessä. Analyysin avulla tutkittiin tekstien implisiittisyyttä ja eksplisiittisyyttä. Teorioiden lukumäärällistä esiintymistä aineistossa tarkasteltiin frekvenssianalyysin avulla. Frekvenssianalyysin analyysiyksikkönä oli virke. Tutkimuksen tulosten mukaan oppikirjoissa painotetaan normatiivisen etiikan teorioista hyve-etiikka sekä seurausetiikka. Velvollisuusetiikka on osana oppikirjojen tekstejä, mutta jää selkeästi vähemmälle huomioille. Normatiivisen etiikan tekstit liittyvät pääosin oppilaiden arkielämän ilmiöihin. Oppikirjojen tekstit olivat suurelta osin implisiittisiä. Implisiittisyys jättää lukijan tai opettajan vastuulle etsiä aiheesta perustellumpaa tietoa. Yksi oppikirjoista käsitteli kaikkia kolmea teoriaa eksplisiittisesti ja teksteissä avataan käsitteiden sisältöä lukijalle perustellen ja esimerkein. Elämänkatsomustiedon oppiaine on oppilasmäärältään pieni ja oppikirjoja on tarjolla vähän. Oppikirjojen teksteissä tarkasteltiin normatiivisen etiikan teorioita monipuolisesti. Tekstien implisiittinen ja tiivis tapa ilmaista asioita johti useissa tapauksissa tekstin tulkitsemisen ja ymmärtämisen vaikeuksiin. Oppikirjojen esimerkeistä puuttuivat internetin käyttöön liittyvät eettiset haasteet, jotka ovat luultavasti osa lasten ja nuorten arkea

Uptake and effectiveness of two-drug compared with three-drug antiretroviral regimens among HIV-positive individuals in Europe

Objective: To assess the use of two-drug antiretroviral regimens (2DR) and virologic and immunologic outcomes compared with three-drug regimens (3DR) in the EuroSIDA cohort. Design: Multicentre, prospective cohort study. Methods: Logistic regression was used to analyse the uptake and outcomes among HIV-positive individuals who started or switched to a 2DR compared with those on a 3DR. Virologic outcomes were assessed on-treatment as the proportion of individuals with controlled viral load (Peer reviewe