The sheet flow viscometer

Not availabl

Challenges and solutions for the eradication of sanitation backlogs in the policy context of Free Basic Sanitation

Despite the constitutional obligation for municipalities to provide Free Basic Sanitation (FBSan) services to all, many people living in informal settlements in South Africa are still lacking access to adequate sanitation facilities. This study used qualitative methods to examine challenges and identify solutions for the eradication of sanitation backlogs in informal settlement of South Africa in the policy context of the FBSan. Findings suggest that the disconnection between the policy and its application in practice has created a deep divide between the service providers and consumers as recipients of the services. Consumers’ perceptions and expectations are a major barrier to the acceptance of the sanitation services provided by municipalities, often resulting in violent protests. Service providers face challenges when addressing the disjuncture between what people aspire to and what is possible in providing sanitation services. These findings infer that consumers’ needs, sanitation practices and settlement conditions should be thoroughly examined prior to the selection and deployment of sanitation facilities in informal settlements. Consumers should be engaged and involved in the choice of sanitation technologies and facilities. Such engagement should evolve around various sanitation technologies and facilities applicable to the nature and context of informal settlements, so as to address negative perceptions, attitudes and behavior concerning services provided by municipalities. Addressing challenges related to the eradication of the sanitation backlogs in the policy context of FBSan services needs to be grounded in the clarification of sanitation policy, a deep understanding of consumers’ needs, challenges and practices as well as settlements conditions, coupled with meaningful consumers’ participation at various stages of the decision-making process and coordination amongst institutions involved. Municipalities need to engage all stakeholders (mainly consumers) in order to ensure that the selected infrastructure and service level deployed are consensual. Unless subjective clauses of the FBSan policy are clarified, monitoring, enforcement and accountability mechanisms established and implemented and, consumers are engaged in the decision making processes, the eradication of sanitation backlogs in informal settlements as currently planned may not materialize

Characterization of Historic Mortars for Compatible Restoration: Case Study of South Africa

The history of the South African construction industry dates as far back as the Castle of Good Hope (1666), Slave Lodge (1679), Robben Island (1700), Union Buildings (1913), memorials and cathedrals, among many others. These structures represent the political, slavery, liberation and religious history of South Africa and its development throughout the years, while also contributing towards economic growth through tourism. Historical buildings stand out from the rest of the modern constructions as they portray marvellous architectural designs and unique materials used for their construction. However, due to ageing and environmental conditions, they often show critical signs of deterioration, which threaten the existence of some. In attempts to rescue these national treasures, the use of Portland cement, which is considered incompatible with the original materials, has become a common practice, not only in South Africa but abroad. To avoid disparity in materials during repair of historic structures, original material characterization is therefore recommended. This paper investigates the effects of Portland cement used on the repairs of historical masonries of the Castle of Good Hope, Cape Town and buildings on Robben Island, in South Africa. The mortar samples were collected from the Castle and analyzed using the techniques such as the visual investigation, cohesion test, microscopic and titration test. It is observed that the original lime- based mortars are not compatible with the Portland cement produced mortars. It was evident on the masonry, as the repairs are repelling from the original surfaces on these two structures

Trade, investment and tax cooperation: tax competition.

The world is facing a new round of international tax competition that may result in a ruinous race to the bottom, undermining the fiscal capacity of states to respond to global challenges and to implement the Agenda 2030. G20 leaders must take action to strengthen multilateral and cooperative approaches to taxation, curtail harmful tax competition and protect their own tax base as well as that of developing countries.Seventh Framework Programme (FP7)758671Grenzen van fiscale soevereinitei

Adaptation in bacterial flagellar and motility systems: from regulon members to ‘foraging’-like behavior in E. coli

Bacterial flagellar motility and chemotaxis help cells to reach the most favorable environments and to successfully compete with other micro-organisms in response to external stimuli. Escherichia coli is a motile gram-negative bacterium, and the flagellar regulon in E. coli is controlled by a master regulator FlhDC as well as a second regulator, flagellum-specific sigma factor, σF. To define the physiological role of these two regulators, we carried out transcription profiling experiments to identify, on a genome-wide basis, genes under the control of these two regulators. In addition, the synchronized pattern of increasing CRP activity causing increasing FlhDC expression with decreasing carbon source quality, together with the apparent coupling of motility activity with the activation of motility and chemotaxis genes in poor quality carbon sources, highlights the importance of CRP activation in allowing E. coli to devote progressively more of its limited reserves to search out better conditions. In adaptation to a variety of carbon sources, the motile bacteria carry out tactical responses by increasing flagellar operation but restricting costly flagellar synthesis, indicating its capability of strategically using the precious energy in nutrient-poor environments for maximizing survival

A Novel Signaling Network Essential for Regulating Pseudomonas aeruginosa Biofilm Development

The important human pathogen Pseudomonas aeruginosa has been linked to numerous biofilm-related chronic infections. Here, we demonstrate that biofilm formation following the transition to the surface attached lifestyle is regulated by three previously undescribed two-component systems: BfiSR (PA4196-4197) harboring an RpoD-like domain, an OmpR-like BfmSR (PA4101-4102), and MifSR (PA5511-5512) belonging to the family of NtrC-like transcriptional regulators. These two-component systems become sequentially phosphorylated during biofilm formation. Inactivation of bfiS, bfmR, and mifR arrested biofilm formation at the transition to the irreversible attachment, maturation-1 and -2 stages, respectively, as indicated by analyses of biofilm architecture, and protein and phosphoprotein patterns. Moreover, discontinuation of bfiS, bfmR, and mifR expression in established biofilms resulted in the collapse of biofilms to an earlier developmental stage, indicating a requirement for these regulatory systems for the development and maintenance of normal biofilm architecture. Interestingly, inactivation did not affect planktonic growth, motility, polysaccharide production, or initial attachment. Further, we demonstrate the interdependency of this two-component systems network with GacS (PA0928), which was found to play a dual role in biofilm formation. This work describes a novel signal transduction network regulating committed biofilm developmental steps following attachment, in which phosphorelays and two sigma factor-dependent response regulators appear to be key components of the regulatory machinery that coordinates gene expression during P. aeruginosa biofilm development in response to environmental cues

Promoter and regulon analysis of nitrogen assimilation factor, σ54, reveal alternative strategy for E. coli MG1655 flagellar biosynthesis

Bacteria core RNA polymerase (RNAP) must associate with a σ factor to recognize promoter sequences. Promoters recognized by the σ54 (or σN) associated RNA polymerase are unique in having conserved positions around −24 and −12 nucleotides upstream from the transcriptional start site. Using DNA microarrays representing the entire Escherichia coli genome and promoter validation approaches, we identify 40 in vivo targets of σ54, the nitrogen assimilation σ factor, and estimate that there are 70 σ54 promoters in total. Immunoprecipitation assays have been performed to further evaluate the efficiency of our approaches. In addition, promoter consensus binding search and primer extension assay helped us to identify a new σ54 promoter carried by insB-5 in the upstream of flhDC operon. The involvement of σ54 in flagellar biosynthesis in sequenced E. coli strain MG1655 indicates a fluid gene regulation phenomenon carried by some mobile elements in bacteria genome

Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in Listeria monocytogenes

Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat

Semi-Autonomous Revenue Authorities in Sub-Saharan Africa: Silver Bullet or White Elephant

A major component of tax administration reform in sub-Saharan Africa for the last 30 years has been the creation of semi-autonomous revenue authorities (SARAs). The effects of their creation on revenue performance have been much debated, although there are only a few quantitative studies. The core argument of this paper is that existing research suggesting diverse and contradictory outcomes has not taken account of trends in revenue performance in the years before the establishment of SARAs. Allowing for this revenue history our analysis based on 46 countries over the period 1980-2015 provides no robust evidence that SARAs induce an increase in revenue performance. This does not imply that SARAs may not provide benefits for tax collection, but they do not demonstrably increase (or decrease) revenue collected