2,433 research outputs found
Design and evaluation of 16S rRNA sequence based oligonucleotide probes for the detection and quantification of Comamonas testosteroni in mixed microbial communities
Background
The β-proteobacterial species Comamonas testosteroni is capable of biotransformation and also biodegradation of a range of chemical compounds and thus potentially useful in chemical manufacturing and bioremediation. The ability to detect and quantify members of this species in mixed microbial communities thus may be desirable.
Results
We have designed an oligonucleotide probe for use in fluorescent in situ hybridization (FISH) and two pairs of PCR primers targeting a C. testosteroni subgroup. The FISH probe and one of the PCR primer pairs are suitable for quantification of C. testosteroni in mixed microbial communities using FISH followed by quantitative image analysis or real-time quantitative PCR, respectively. This has been shown by analysis of samples from an enrichment of activated sludge on testosterone resulting in an increase in abundance and finally isolation of C. testosteroni. Additionally, we have successfully used quantitative PCR to follow the C. testosteroni abundance during a laboratory scale wastewater bioaugmentation experiment.
Conclusion
The oligonucleotides presented here provide a useful tool to study C. testosteroni population dynamics in mixed microbial communities
New Species of Siparuna (Siparunaceae) IV
A new species of Siparuna (Siparunaceae),
S. ficoides, is described, illustrated, and
placed in a phylogenetic context based on morphological and DNA sequence data. The species, which is a monoecious subcanopy tree, is known from three collections made near Manaus, Brazil (two from the same tree), and one in the state of Bolivar, Venezuela.Se describe y se ilustra una nueva especie de Siparuna (Siparunaceae), S. ficoides, ademas se la ubica en un contexto filogenetico basado en datos morfologicos y en sequencias de DNA. Esta nueva especie es un arbol monoico de subdosel, de la cual se han registrado tres colecciones cerca de Manaos, Brasil (dos del mismo arbol) y una coleccion en el Estadod e Bolivar, Venezuela
New Species of Siparuna (Siparunaceae) III
Three new species of Siparuna (Siparunaceae) are described, illustrated, and placed in a phylogenetic context: S. gentryana from western Ecuador and adjacent Colombia, S. lozaniana from the western Andes in Colombia, and S. vasqueziana from Amazonian Peru. In addition, Siparuna calantha from the Sierra Nevada de Santa Marta, originally described by Janet Perkins as a variety of a Mexican entity, is raised to species rank because its broader leaves and more numerous carpels readily distinguish it from its apparent closest relative, a species from the western Colombian Andes. Each of the species is known from several collections, which allowed the secure matching of sexual morphs in the three that are dioecious
Effect of the powder characteristics of Sisub3Nsub4 on the microstructure of sintered bodies
Silicon nitride powders sintered with the addition of 2 wt% Mg0 to 95% theoretical density after attrition milling and subsequent purification were evaluated. Preparation of the powders is described. The powder characteristics (specific surfaces, iron concentration, and oxygen content), and density, weight loss, and phase state of the sinter bodies as a function of powder preparation are presented
Transitions of social-ecological subsistence systems in the Arctic
Transitions of social-ecological systems (SES) expose governance systems
to new challenges. This is particularly so in the Arctic where resource systems
are increasingly subjected to global warming, industrial development and globalization
which subsequently alter the local SES dynamics. Based on common-pool
resource theory, we developed a dynamic conceptual model explaining how exogenous
drivers might alter a traditional subsistence system from a provisioning to
an appropriation actions situation. In a provisioning action situation the resource
users do not control the resource level but adapt to the fluctuating availability of
resources, and the collective challenge revolve around securing the subsistence in
the community. An increased harvest pressure enabled by exogenous drivers could
transform the SES to an appropriation action situation where the collective challenge
has changed to avoid overuse of a common-pool resource. The model was
used as a focal lens to investigate the premises for broad-scale transitions of subsistence-oriented
SESs in Arctic Alaska, Canada and Greenland. We synthesized
data from documents, official statistics and grey and scientific literature to explore
the different components of our model. Our synthesis suggests that the traditional
Arctic subsistence SESs mostly comply with a provisioning action situation.
Despite population growth and available technology; urbanization, increased wage
labor and importation of food have reduced the resource demand, and we find no
evidence for a broad-scale transition to an appropriation action situation throughout
the Western Arctic. However, appropriation challenges have emerged in some
cases either as a consequence of commercialization of the resource or by severely
reduced resource stocks due to various exogenous drivers. Future transitions of
SESs could be triggered by the emergence of commercial local food markets and
Arctic warming. In particular, Arctic warming is an intensifying exogenous driver
that is threatening many important Arctic wildlife resources inflicting increased
appropriation challenges to the governance of local harvest.Ye
Impediments to agricultural growth in Zambia:
This paper has been prepared as part of the Zambia country study of the Macroeconomic and Regional Integration in Southern Africa (MERRISA) project and serves as a background paper for modeling exercises. The paper focuses on analyzing institutional constraints on the development of the agricultural sector in Zambia. It argues that by changing some of the rules and neglecting to integrate these changes into the complete institutional setting, policymakers have been unable to achieve their goals. Other constraints on Zambia's agricultural development are of a more technical nature. There are problems with Zambia's infrastructure. This paper argues that these are problems of the provision of public and merit goods mainly occurring in rural areas. Farmers emphasize their limited access to resources like credit, fertilizer, and draft animals. Although these problems could indicate market failures, it is the view of the authors that they are mainly due to transition uncertainties.Resource management., Infrastructure (Economics) Rural areas Zambia., Agricultural development., Agricultural resources.,
ECONOMIC REFORMS IN POLAND: IMPLICATIONS FOR AGRICULTURE
Throughout the world, agriculture has become integrated into the economy at large. Therefore, it is not possible to analyze the process of economic and political transformation of agriculture without reference to the general thrust and speed of reform (Pasour, 1992). In this paper, we will argue that Poland, like other countries in Central and Eastern Europe, faces a dilemma of economic and political reform. Further, we will discuss some of the central variables which tend to constrain the process of economic transition and recovery. Following we will first discuss some of the central effects of partial and stepwise economic reform. Second, we will analyze the pros and cons of economic shock therapy, i.e., of a rapid switch to a market economic system and its implications for institutional change. Third, we will try to shed light on some of the political economic aspects of transformation. Fourth we will discuss a number of factors constraining the speed of economic recovery. We will conclude with some remarks about the prospects for economic transition in Polish agriculture.Political Economy,
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