Detection and enumeration of Campylobacter jejuni and Campylobacter coli by indirect impedimetry with an oxygen scavenging system

Six strains of Campylobacter jejuni and Campylobacter coli were shown to grow in a variety of media, but, with one exception, they were unable to produce sufficient change in the electrical properties of the medium to allow their detection by impedance monitoring. With the use of an indirect method based on absorption of evolved carbon dioxide and a medium containing the oxygen scavenger Oxyrase, all strains were detectable, and correlations between time to detection and the logarithm of the inoculum level were excellent. The level of interstrain variation was sufficiently low that all data could be consolidated into a single calibration curve (r = 0.987).     

Dioxins,furans, and non-ortho PCBs in Canadian Arctic seabirds

This is the first account of PCDDs, PCDFs, and non-ortho PCBs in Canadian Arctic seabirds. Livers and eggs of thick-billed murres, northern fulmars, and black-legged kittiwakes were collected in 1975 and 1993 from Prince Leopold Island in Lancaster Sound, Canada. Detectable concentrations of PCDDs, PCDFs, and non-ortho PCBs were found in all the Arctic seabird samples analyzed. Of the PCDD congeners assayed, only 2,3,7,8-substituted PCDDs were detected in the samples, whereas non-2,3,7,8-substituted PCDFs were found in addition to 2,3,7,8-substituted PCDFs in some of the samples. The predominant PCDD/F congener found in the livers of all three species was 2,3,4,7,8-PnCDF, both in 1975 and 1993. Concentrations of most dioxins and furans decreased in the fulmars and kittiwakes between 1975 and 1993 but increased in the murres. Of the non-ortho PCBs measured, PCB-126 occurred in the highest concentrations and contributed the majority of the non-ortho PCB-TEQ in all three species in both years. The highest concentrations of dioxins and furans as well as the highest TEQ values were found in the northern fulmar livers in both 1975 and 1993. Concentrations of some of the PCDDs and PCDFs are among the highest reported for Canadian Arctic biota.     

Microrheology: new methods to approach the functional properties of food

Three configurations have been developed to improve the understanding of structural element interactions in food material during deformation. The three configurations combine an inverted confocal scanning laser microscope (CSLM) and a cell that can apply to the sample a specific deformation: continuous shear, linear oscillatory shear and biaxial extension (compression).In the continuous shear and oscillatory shear configurations (OSCs), a zero-velocity plane is created in the sample by moving two plates in opposite direction, maintaining stable observation conditions of the structural behaviour under deformation. The OSC allows simultaneous application of CSLM and diffusing wave spectroscopy, a multiple light scattering technique. The third configuration (compression configuration) allows observation at a stagnation point during rheometric measurements. The configurations accept semi-liquid products (dressing, sauces, dairy products, etc.) for investigations in area such as aggregation, gelation, interactions at interface, coalescence, break-up.     

Physicochemical changes in intermediate-moisture protein bars made with whey protein or calcium caseinate

This study examined model protein bars made with whey protein isolate (WPI) or calcium caseinate and stored at 20 °C for 50 days. WPI bars remained very soft and, throughout storage, confocal micrographs showed a continuous matrix containing soluble protein and increasing quantities of glucose crystals. In contrast, calcium caseinate bars had a firm texture within 1–5 days of manufacture (fracture stress 199 ± 16 Pa) and hardened progressively during storage (final fracture stress 301 ± 18 Pa). Electrophoresis showed no evidence of covalent protein aggregation, but there were substantial changes in microstructure over the first day of storage, resulting in segregation of a protein phase from a water–glucose–glycerol phase. Proton nuclear magnetic resonance (¹H-NMR) relaxometry and nuclear Overhauser effect spectroscopy (NOESY) experiments showed that water migration away from protein towards glucose and glycerol occurred 10–18 h after manufacture, lowering the molecular mobility of protein. Phase separation was probably driven by the high osmotic pressure generated by the glucose and glycerol. These results confirm that the hardening of protein bars is driven by migration of water from protein to glucose and glycerol, and microstructural phase separation of aggregated protein.     

Costs of mastitis: facts and perception

A model to calculate the economic losses of mastitis on an average Dutch dairy farm was developed and used as base for a tool for farmers and advisors to calculate farm-specific economic losses of mastitis. The economic losses of a clinical case in a default situation were calculated as euro210, varying from euro164 to euro235 depending on the month of lactation. The total economic losses of mastitis (subclinical and clinical) per cow present in a default situation varied between euro65 and euro182/cow per year depending on the bulk tank somatic cell count. The tool was used to measure perception of the total economic losses of mastitis on the farm and the farmers' assessment of the cost factors of mastitis on 78 dairy farms, of which 64 were used for further analyses. Most farmers (72%) expected their economic losses to be lower than those revealed by our calculation made with their farm information. Underestimating the economic losses of mastitis can be regarded as a general problem in the dairy sector. The average economic losses assessed by the farmers were euro78/cow per year, but a large variation was given, euro17-198/cow per year. Although the average assessment of the farmers of the different cost factors is close to the default value, there is much variation. To improve the adoption rate of advice and lower the incidence of mastitis, it is important to show the farmers the economic losses of mastitis on their farm. The tool described in this paper can play a role in that process.     

Global analysis of the riverine transport of 90Sr and 37Cs

Atmospheric nuclear weapons explosions and large-scale nuclear accidents may contaminate large areas of land with the long-lived radionuclides 137Cs and 90Sr. The mobility and bioavailability of these radionuclides in the environment is dependent primarily on soil characteristics and changes significantly over time after fallout (1-4). Radioisotope concentrations in different rivers and at different times after fallout vary over 2-3 orders of magnitude. Many previous studies have concentrated on the interactions of radiocesium and radiostrontium with various environmental components, but there are currently no operative models fortheirtransport over large spatial areas. We collected time-series measurements of 90Sr and 137Cs in 25 major European and Asian rivers and (using digital data sets with global coverage) determined characteristics of each of the rivers' catchments. This work has established, for the first time, a quantitative link between riverine transport of these radioisotopes and catchment and soil characteristics at a global scale. A generalized predictive model accounting for time changes in river concentrations and variation in catchment characteristics is developed. This can be used to predict the long-term riverine transport of these radiologically important radionuclides following any large-scale nuclear incident in North America, Europe, or (European and Asian) Russia.     

Carbon speciation of diesel exhaust and urban particulate matter NIST standard reference materials with C(1s) NEXAFS spectroscopy

The U.S. National Institute of Standards and Technology (NIST) provides a number of particulate matter (PM) standard reference materials (SRM) for use in environmental and toxicological methodology and research. We present here the first analysis with respect to the molecular structure of the carbon in three such NIST SRM samples, i.e., diesel engine exhaust soot from heavy duty equipment engines (SRM 1650), diesel soot from a forklift engine (SRM 2975), and urban PM collected in St. Louis, MO (SRM 1648), with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NEXAFS spectra of the two diesel soot samples appear quite similar, while they differ significantly from the urban PM spectrum, in agreement with X-ray diffraction data published recently. Such comparison is made in terms of aromatic and aliphatic carbon species, as well as by a general comparison with graphitic materials. Both diesel soot SRM samples contain basic graphitic structures, but the presence of exciton resonance and extended X-ray absorption fine structure oscillations in SRM 1650 and the lack therof in SRM 2975 suggest that SRM 1650 is the more graphitic material.The presence of polycyclic aromatic hydrocarbons, which have a characteristic NEXAFS resonance at the same position as graphite, can obscure the graphitic character of soot, unless an extraction of the organic matter is made. Our NEXAFS data do not suggest that the urban PM sample SRM 1648 contains a substantial amount of graphite-like material.     

Entering our 16th year

Background and objective

British American Tobacco (BAT) has historically enjoyed a monopoly position in Kenya. Analysis of recent tobacco control debates and a case study of BAT''s response to the emergence of competition in Kenya are used to explore the company''s ability to shape public policy and its treatment of tobacco farmers.

Design

Analysis of internal industry documents from BAT''s Guildford depository, other relevant data and interviews with key informants.

Results

BAT enjoys extensive high‐level political connections in Kenya, including close relationships with successive Kenyan presidents. Such links seems to have been used to influence public policy. Health legislation has been diluted and delayed, and when a competitor emerged in the market, BAT used its contacts to have the government pass legislation drafted by BAT that compelled farmers to sell tobacco to BAT rather than to its competitor. BAT was already paying farmers less than any other African leaf‐growing company, and the legislation entrenched poor pay and a quasi‐feudal relationship. BAT''s public relation''s response to the threat of competition and the ministers'' public statements extolling the economic importance of tobacco growing suggest that BAT has manipulated tobacco farming as a political issue.

Conclusions

The extent of BAT''s influence over public policy is consistent with the observations that, despite ratifying the Framework Convention on Tobacco Control, progress in implementing tobacco control measures in Kenya has been limited. The benefits of tobacco farming seem to be deliberately exaggerated, and an analysis of its true cost benefits is urgently needed. Tobacco farmers must be protected against BAT''s predatory practices and fully informed about its activities to help them have an informed role in policy debates. As image, particularly around the importance of tobacco farming, seems key to BAT''s ability to influence policy, the truth about its treatment of farmers must be publicised.Driven by the recent expansion of transnational tobacco corporations (TTCs) across many low‐ and middle‐income countries, the burden of tobacco''s health effect is shifting. It is predicted that, by 2030, 70% of the estimated 10 million global deaths from tobacco will occur in developing countries.¹ In this context, sub‐Saharan Africa (SSA) offers an opportunity for global health, being the only region in the world where primary prevention of the tobacco epidemic remains possible.² However, with TTCs investing heavily in the region during the last decade and with evidence of rapidly rising consumption, particularly among youth,³ this window of opportunity is closing rapidly.Implementation of comprehensive regulatory measures is required to prevent further escalation of the epidemic in SSA, and the World Health Organisation''s Framework Convention on Tobacco Control (FCTC) provides excellent opportunities in this regard. The African nations recognised this in pressing unanimously for a comprehensive treaty while simultaneously acknowledging the need to find an alternative income for countries dependent on tobacco farming, notably Zimbabwe and Malawi.^2,3 Tobacco farming represents a unique dimension to the tobacco control debate in SSA, and previous analyses of tobacco industry documents suggest that the tobacco industry has attempted to hijack such debates by presenting tobacco control as a “first world” concern that would lead to economic destabilisation and exacerbate poverty and malnutrition among tobacco‐growing countries.⁴ By contrast, a growing body of evidence suggests that tobacco farmers face considerable financial and health risks from growing tobacco.^{5,6,7,8,9,10,11,12}As African nations seek to implement the provisions of the FCTC, tobacco control legislation will have to be developed and enacted, providing opportunities for the tobacco industry to influence policy. The fact that Kenya has signed and ratified the FCTC¹³ while (as detailed below) efforts to implement legislation consistent with the treaty have been unsuccessful amid persistent reports of BAT influence¹⁴ highlights the possible barriers. Hence, there is an urgent need to understand the tobacco control policy environment in Africa, including the relationships between tobacco farmers and TTCs, which are clearly integral to this. However, there remains a dearth of research in this area. This paper seeks to address this gap by examining British American Tobacco''s (BAT) policy influence in Kenya.BAT merits particular attention as it is the dominant player in SSA, with a market share of over 90% in 11 countries.³ The selection of Kenya reflects its significance to BAT''s operations in Africa, the role it seems to have in BAT''s efforts to influence policy regionally¹⁵ and the nature of Kenyan tobacco politics.After an introduction to the origins and character of BAT''s political influence in Kenya and an overview of recent tobacco control debates in the country, this paper uses a case study of the company''s response to an emergent competitor, Mastermind Tobacco Kenya (referred to in the documents as MTK or MTCo), to examine BAT''s influence on policymaking. The paper therefore aims to shed important light on issues critical to the development of tobacco control across SSA.     

Aeration and gutter water levels in siphonic roof drainage systems

An investigation is presented into how negative system pressures, the degree of aeration, and gutter water levels are affected by the number of outlets in a siphonic roof drainage system. The experimental results show that system pressures decrease if outlets are blocked. It is also shown that the depth of water above an outlet is strongly influenced by the negative pressure acting at the outlet. As the suction effect at the outlet increases, due to lower system pressures, more water and air will be drawn into the outlets and this will result in a corresponding increase in overall gutter water depth. The results also show that there is often built-in redundancy in multiple outlet siphonic systems experiencing lower-intensity rainfall events, and if one or two outlets were blocked, the system would still operate satisfactorily. A new outlet suppressor was trialled and this was shown to reduce gutter water levels by up to 58% at some positions in the gutter.

Il est présenté une enquête sur la manière dont les pressions négatives dans le système concerné, le degré d'aération et les niveaux d'eau dans les chéneaux sont affectés par le nombre d'orifices de sortie dans un système d'écoulement des eaux de toit par siphonnage. Les résultats expérimentaux montrent que les pressions dans le système diminuent si des orifices de sortie sont obturés. Il est également montré que la profondeur de l'eau au-dessus d'un orifice de sortie est fortement influencée par la pression négative s'exerçant à l'orifice de sortie. Plus l'effet de succion à l'orifice de sortie augmente, en raison des pressions plus faibles dans le système, et plus les quantités d'air et d'eau entraînées dans les orifices de sortie seront importantes, et cela aura pour résultat une augmentation correspondante de la profondeur générale de l'eau dans les chéneaux. Les résultats montrent également qu'il existe souvent une redondance intégrée dans les systèmes à siphons comportant des orifices de sortie multiples et soumis à des épisodes pluvieux de faible intensité, et que si un ou deux orifices de sortie sont obturés, le système fonctionne encore de manière satisfaisante. Un nouvel obturateur d'orifice de sortie a été essayé, ce qui a permis de montrer que celui-ci réduit dans une proportion allant jusqu'à 58 % en certains points les niveaux d'eau dans les chéneaux.

Mots clés: aération, niveaux d'eau dans les chéneaux, pressions négatives, écoulement des eaux de toit par siphonnage