Thelytokous parthenogenesis by queens in the dacetine ant Pyramica membranifera (Hymenoptera: Formicidae)

Thelytokous parthenogenesis in which diploid females are produced from unfertilized eggs, was recently reported for some ant species. Here, we document thelytokous reproduction by queens in the polygynous species Pyramica membranifera. Queens that emerged in the laboratory were kept with or without workers under laboratory conditions. Independent colony founding was successful for a few queens if prey was provided. All artificial colonies, which started with a newly emerged queen and workers produced new workers and some of the colonies also produced female sexuals. Some of the female sexuals shed their wings in the laboratory and started formation of new polygynous colonies. Workers had no ovaries and thus, were obligatorily sterile.     

Biological hydrogen production by Rhodobacter capsulatus in solar tubular photo bioreactor

The purpose of this study was to develop a pilot scale tubular photo bioreactor (80 L) for photo fermentative hydrogen production by photosynthetic purple-non-sulfur bacterium, Rhodobacter capsulatus, operating in outdoor conditions, using acetate as the carbon source. The reactor was operated continuously in fed-batch mode for 30 days throughout December 2008 in Ankara. It was placed in a greenhouse in order to keep the temperature above freezing levels. It was found that R. capsulatus had a rapid growth with a specific growth rate of 0.025 h^?1 in the exponential phase. The growth was defined with modified logistic model for long term duration. The hydrogen production and feeding started in the late exponential phase. Evolved gas contained 99% hydrogen and 1% carbon dioxide by volume. The average molar productivity calculated during daylight hour was 0.31 mol H₂/(m³ h) with regard to the total reactor volume and 0.112 mol H₂/(m²·day) with regard to the total illuminated surface area. It was proven that even at low light intensities and low temperatures, the acetic acid which was fed to the system can be utilized for biosynthesis, growth and hydrogen production. The overall hydrogen yield was 0.6 mole H₂ per mole of acetic acid fed. This study showed that photofermentation in a pilot scale tubular photo bioreactor can produce hydrogen, even in winter conditions.     

Nanosecond pulsed laser micromachining of PMMA-based microfluidic channels

This paper reports an investigation into the effects of nanosecond laser processing parameters on the geometry of microchannels fabricated from polymethylmethacrylate (PMMA). The Nd:YAG solid-state pulsed laser has a wavelength of 1064 nm and a measured maximum power of 4.15 W. The laser processing parameters are varied in a scanning speed range of 400–800 pulses/mm, a pulse frequency range of 5–11 Hz, a Q-switch delay time range of 170–180 μs. Main effects plots and microchannel images are utilized to identify the effects of the process parameters for improving material removal rate and surface quality simultaneously for laser micromachining of microchannels in PMMA polymer. It is observed that channel width and depth decreased linearly with increasing Q-switch delay time (hence average power) and increased non-linearly with higher scanning rates and not much affected by the increase in pulse frequency.     

Between adaptability and the urge to control: making long-term water policies in the Netherlands

Triggered by recent flood catastrophes and increasing concerns about climate change, scientists as well as policy-makers increasingly call for making long-term water policies to enable a transformation towards flood resilience. A key question is how to make these long-term policies adaptive so that they are able to deal with uncertainties and changing circumstances. The paper proposes three conditions for making long-term water policies adaptive, which are then used to evaluate a new Dutch water policy approach called ‘Adaptive Delta Management’. Analysing this national policy approach and its translation to the Rotterdam region reveals that Dutch policy-makers are torn between adaptability and the urge to control. Reflecting on this dilemma, the paper suggests a stronger focus on monitoring and learning to strengthen the adaptability of long-term water policies. Moreover, increasing the adaptive capacity of society also requires a stronger engagement with local stakeholders including citizens and businesses.     

Fungal survival during anaerobic digestion of organic household waste

Anaerobic digestion of organic waste yields energy rich biogas and retains nutrients (N, P, K, S, etc.) in a stabilised residue. For the residue to be used as a soil fertiliser, it must be free from pollutants and harmful microorganisms. Fungal survival during sanitation and anaerobic treatment of source-separated organic household waste and during aerobic storage of the residue obtained was investigated. Decimal reduction times were determined for inoculated fungi (Aspergillus flavus and Aspergillus fumigatus, Penicillium roqueforti, Rhizomucor pusillus, Thermoascus crustaceus and Thermomyces lanuginosus). Several different fungal species were found after waste sanitation treatment (70 degrees C, 1 h), with Aspergillus species dominating in non-inoculated waste. Anaerobic waste degradation decreased the diversity of fungal species for processes run at both 37 and 55 degrees C, but not total fungal colony forming units. Fungi surviving the mesophilic anaerobic digestion were mainly thermotolerant Talaromyces and Paecilomyces species. T. crustaceus and T. lanuginosus were the only inoculated fungi to survive the thermophilic anaerobic degradation process. Aerobic storage of both types of anaerobic residues for one month significantly decreased fungal counts.     

Quality and Quantity of Leachate in Aerobic Pilot-Scale Landfills

In this study, two pilot-scale aerobic landfill reactors with (A1) and without (A2) leachate recirculation are used to obtain detailed information on the quantity and quality of leachate in aerobic landfills. The observed parameters of leachate quality are pH, chloride (Cl⁻), chemical oxygen demand (COD), biological oxygen demand (BOD), total Kjeldahl nitrogen (TKN), ammonia nitrogen (NH₃-N), and nitrate (NO₃^–-N). pH values of the leachate increased to 7 after 50 days in reactor A1 and after 70 days in reactor A2. Cl⁻ concentrations increased rapidly to 6100 (A1) and 6900 (A2) mg/L after 80 days, from initial values of 3000 and 2800 mg/L, respectively. COD and BOD values decreased rapidly in the A1 landfill reactor, indicating the rapid oxidation of organic matter. The BOD/COD ratio indicates that leachate recirculation slightly increases the degradation of solid waste in aerobic landfills. NH₃-N concentrations decreased as a result of the nitrification process. Denitrification occurred in parts of the reactors as a result of intermittent aeration; this process causes a decrease in NO₃⁻ concentrations. There is a marked difference between the A1 and A2 reactors in terms of leachate quantity. Recirculated leachate made up 53.3% of the leachate generated from the A1 reactor during the experiment, while leachate quantity decreased by 47.3% with recirculation when compared with the aerobic dry landfill reactor.     

Seasonal variations of heavy metals in some organs of carp (Cyprinus carpio L., 1758) from Beyşehir Lake (Turkey)

In this study which was carried out between March 2003 and February 2005 Fe, Cu, Zn, Mn, Cr, Pb and Cd contents were determined in muscle, liver and gill of carp (Cyprinus carpio L., 1758) caught from Beyşehir Lake. Among the heavy metals analyzed Cr, Pb and Cd were below the detection limit (<0.03). Heavy metal concentrations varied significantly depending on the type of the tissue and season. The highest metal concentrations were found in the liver, followed by gill and muscle. Heavy metal levels in tissues of carp were increased in summer and winter, while were decreased in autumn and spring. The present study shows that precautions need to be taken in Beyşehir Lake in order to prevent heavy metal pollution that can occur in the future.     

The fatty acid compositions of several plant seed oils belong to Leguminosae and Umbelliferae families

In samples with 1,009, 7,723, 7,618, 7,618, 1,004 and 1,009 number, oleic acid were found as 62.0, 77.0, 74.84, 71.55, 54.52 and 62.30 %, respectively. In other samples, oleic acid content was determined between 17.43 % (1,589) and 34.86 % (1,298). Linoleic acid content of seed oils ranged from 6.52 % (7,727) to 57.29 % (1,501). In addition, linolenic acid content was found between 0.22 % (7,618) and 46.91 % (1,589). Palmitic acid content of samples changed between 2.03 % (7,727) and 19.81 % (1,298). Capric acid was found at high level in 1,009 (8.53 %), 7,727 (37.31 %) and 1,004 (8.28 %) samples. Caproic acid was found in only 7,727 (3.38 %).