Decomposition of coarse woody debris in a long-term litter manipulation experiment: A focus on nutrient availability

The majority of above-ground carbon in tropical forests is stored in wood, which is returned to the atmosphere during decomposition of coarse woody debris. However, the factors controlling wood decomposition have not been experimentally manipulated over time scales comparable to the length of this process.We hypothesized that wood decomposition is limited by nutrient availability and tested this hypothesis in a long-term litter addition and removal experiment in a lowland tropical forest in Panama. Specifically, we quantified decomposition using a 15-year chronosequence of decaying boles, and measured respiration rates and nutrient limitation of wood decomposer communities.The long-term probability that a dead tree completely decomposed was decreased in plots where litter was removed, but did not differ between litter addition and control treatments. Similarly, respiration rates of wood decomposer communities were greater in control treatments relative to litter removal plots; litter addition treatments did not differ from either of the other treatments. Respiration rates increased in response to nutrient addition (nitrogen, phosphorus, and potassium) in the litter removal and addition treatments, but not in the controls.Established decreases in concentrations of soil nutrients in litter removal plots and increased respiration rates in response to nutrient addition suggest that reduced rates of wood decomposition after litter removal were caused by decreased nutrient availability. The effects of litter manipulations differed directionally from a previous short-term decomposition study in the same plots, and reduced rates of bole decomposition in litter removal plots did not emerge until after more than 6 years of decomposition. These differences suggest that litter-mediated effects on nutrient dynamics have complex interactions with decomposition over time

Isolation and propagation of Trypanosoma brucei gambiense from sleeping sickness patients in south Sudan

This study aimed at isolating Trypanosoma brucei gambiense from human African trypanosomiasis (HAT) patients from south Sudan. Fifty HAT patients identified during active screening surveys were recruited, most of whom (49/50) were in second-stage disease. Blood and cerebrospinal fluid samples collected from the patients were cryopreserved using Triladyl® as the cryomedium. The samples were stored at −150 °C in liquid nitrogen vapour in a dry shipper. Eighteen patient stabilates could be propagated in immunosuppressed Mastomys natalensis and/or SCID mice. Parasitaemia was highest in SCID mice. Further subpassages in M. natalensis increased the virulence of the trypanosomes and all 18 isolates recovered from M. natalensis or SCID mice became infective to other immunosuppressed mouse breeds. A comparison of immunosuppressed M. natalensis and Swiss White, C57/BL and BALB/c mice demonstrated that all rodent breeds were susceptible after the second subpassage and developed a parasitaemia >106/ml by Day 5 post infection. The highest parasitaemias were achieved in C57/BL and BALB/c mice. These results indicate that propagation of T. b. gambiense isolates after initial isolation in immunosuppressed M. natalensis or SCID mice can be done in a range of immunosuppressed rodent

Ethical issues in the use of in-depth interviews: literature review and discussion

This paper reports a literature review on the topic of ethical issues in in-depth interviews. The review returned three types of article: general discussion, issues in particular studies, and studies of interview-based research ethics. Whilst many of the issues discussed in these articles are generic to research ethics, such as confidentiality, they often had particular manifestations in this type of research. For example, privacy was a significant problem as interviews sometimes probe unexpected areas. For similar reasons, it is difficult to give full information of the nature of a particular interview at the outset, hence informed consent is problematic. Where a pair is interviewed (such as carer and cared-for) there are major difficulties in maintaining confidentiality and protecting privacy. The potential for interviews to harm participants emotionally is noted in some papers, although this is often set against potential therapeutic benefit. As well as these generic issues, there are some ethical issues fairly specific to in-depth interviews. The problem of dual role is noted in many papers. It can take many forms: an interviewer might be nurse and researcher, scientist and counsellor, or reporter and evangelist. There are other specific issues such as taking sides in an interview, and protecting vulnerable groups. Little specific study of the ethics of in-depth interviews has taken place. However, that which has shows some important findings. For example, one study shows participants are not averse to discussing painful issues provided they feel the study is worthwhile. Some papers make recommendations for researchers. One such is that they should consider using a model of continuous (or process) consent rather than viewing consent as occurring once, at signature, prior to the interview. However, there is a need for further study of this area, both philosophical and empirical

Adapted hydropower-driven water supply system: assessment of an underground application in an Indonesian karst area

Populated karst landscapes can be found all over the world, although their natural boundary conditions mostly lead to distinct challenges regarding a sustainable water supply. Especially in developing and emerging countries, this situation aggravates since appropriate technologies and water management concepts are rarely available. Against this background, the interdisciplinary, German-Indonesian joint project ‘‘Integrated Water Resources Management (IWRM) Indonesia’’, funded by the German Federal Ministry of Education and Research (BMBF), focused on the development and exemplary implementation of adapted techniques to remedy the partly severe water scarcity in the region Gunung Sewu. This karst area, widely known as ‘‘Java’s poorhouse’’, is located on the southern coast of Java Island and distinctly suffers from the mentioned constraints. Under the aegis of the Karlsruhe Institute of Technology (KIT), the conceptual and technical achievements of the ‘‘IWRM Indonesia’’ joint research project are characterized by a high potential for multiplication not only for karst areas but also for nonkarst regions. One of the project’s major accomplishments is the erection of an innovative hydropower-driven water supply facility located in a karst cave 100 m below ground and continuously supplying tens of thousands of people with fresh water. Referring to the plant’s innovative character and the demanding conditions on-site, the implementation was a highly iterative process leading to today’s autonomous operation by an Indonesian public authority. Based on the experiences gained during design, construction, operation and monitoring phase, this paper introduces an implementation approach for adapted technologies as well as a comprising technical and economical assessment of the plant’s operation

A new measurement of the neutron detection efficiency for the NaI Crystal Ball detector

We report on a measurement of the neutron detection efficiency in NaI crystals in the Crystal Ball detector obtained from a study of single p0 photoproduction on deuterium using the tagged photon beam at the Mainz Microtron. The results were obtained up to a neutron energy of 400 MeV. They are compared to previous measurements made more than 15 years ago at the pion beam at the BNL AGS

Quasi-free photoproduction of η-mesons off 3He nuclei

Quasi-free photoproduction of η-mesons has been measured off nucleons bound in 3He nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4π covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The η-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S11(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects

Organische Düngung in der Karpfenteichwirtschaft: Fischertrag und Umweltaspekte

Dieses Mesokosmenexperiment befasst sich mit verschiedenen Maßnahmen zur Steigerung der Naturnahrung in Teichen unter Nutzung natürlicher Ressourcen. Das Ziel war, Naturertrag, Nachhaltigkeit und Produktqualität in der Karpfenteichwirtschaft zu verbessern. Durch organische Düngung mit Pferde- und Hühnermist (3t/ha) konnte in Teichen mit nährstoffärmeren Teichböden (P2O5-CAL 13,4 mg/100 g Boden) die Nährtierdichte erhöht und der Fischertrag durchschnittlich um etwa 200 kg/ha gesteigert werden. Zudem hatte die organische Düngung am Ende der Produktionsperiode keinen signifikanten Einfluss auf die Wasser- und Bodenqualitätsparameter