Nuisance Level Research Articles

Frequency and Nuisance Level of Adverse Events in Individuals Receiving Homologous and Heterologous COVID-19 Booster Vaccine

This study aimed to compare the occurrence and nuisance of adverse events following administration of each COVID-19 vaccine dose between two groups: individuals given three doses of mRNA vaccine (homologous group, 3 × mRNA, n = 252) and those given two doses of adenoviral vector vaccine further boosted with mRNA vaccine (heterologous group, 2 × AZ + 1 × mRNA, n = 205). Although the studied groups differed significantly in the frequency and number of side effects after the first and second vaccine dose, no relevant differences were seen following the booster administration. Arm pain and fatigue were the most common effects, regardless of the vaccination group and vaccine dose. In the homologous group, female sex, lower BMI, and no history of regular influenza vaccination were associated with a higher frequency of side effects of a booster dose. In the heterologous group, the history of COVID-19 was associated with an increased number of side effects seen after a booster. In both groups, the number of side effects related to the first and second dose correlated with the number observed after administration of a booster dose. Individuals receiving a homologous booster reported a higher nuisance of side effects than the heterologous group. It was similar to the level reported after the second dose in both groups. The use of pharmaceuticals to counteract the side effects was more frequent after a first dose in the 2 × AZ + 1 × mRNA group, but higher after second dose in individuals receiving the 3 × mRNA vaccination scheme. The frequency of pharmaceutical use after a booster dose was similar in both groups (approx. 60%). Paracetamol was most frequently chosen, regardless of the group and vaccine dose. In addition, the vast majority of participants (93%) declared to accept future doses of the COVID-19 vaccine if their administration would be recommended. This study provides an overview of the response to homologous and heterologous mRNA vaccine booster dose that may be valuable in shaping accurate and honest communication with vaccinated individuals, especially in those regions which are yet to pursue booster strategies.

Wearable Chemical Sensor Badge

Objectives Under this program, a wearable chemical detection badge capable of detecting and alarming (visual + audible/vibratory) in the presence of relevant concentrations of toxic industrial chemicals (TICs) in air has been developed and demonstrated for ammonia, chlorine, hydrogen sulfide, and nitrogen dioxide. The badge will alarm via one of the user-chosen alarm modes in the presence of ½ Immediately Dangerous to Life or Health (1/2 IDLH) concentrations of these TICs in under 5 minutes. The technology operates in harsh environmental conditions (10-90% RH, -10 – 50 oC) and in the presence of interferents (e.g. smoke, fuels, bleach and diesel exhaust). The active sampling badge consists of a reusable detection device that is used in conjunction with a disposable colorimetric sensor coupon. The sensor badge is unobtrusive and can be worn in the breathing zone of the user with hands-free operation for up to 8 hours on battery power. Results Small prototype devices (2” x 2” x 0.5”) were manufactured based on feedback from expert first responder personnel. Key points from this feedback include: Must have a low false alarm rate; no nuisance level alarms (e.g. PEL)Alarm must be very visible/noticeableMust be small and unobtrusiveData logging would be beneficial for analysis at a later time Prototype devices and associated sensor coupons were tested in the presence of PEL, ½ IDLH, and multiple IDLH concentrations of the target TIC analytes (ammonia, chlorine, hydrogen sulfide, and nitrogen dioxide) under harsh environmental conditions: -10 oC, ~ 90%RH 23 oC, 10% RH/50% RH/90% RH 50 oC, 10% RH/50% RH/90% RHand in the presence of environmental interferents including smoke (burning wood), diesel exhaust, diesel fuel and bleach. Utilizing four interrogation bands of the visible spectrum and combinatorial colorimetric response alarm criteria, the prototype badges performed well with no false positive or false negative alarms due to environmental interferent exposure, nuisance level (PEL) exposure, or harsh environmental conditions. Conclusion/Significance First Responders under duress need a simple, low-cost, rugged device capable of detecting the presence of harmful levels of Toxic Industrial Chemicals (TICs) with high fidelity while avoiding nuisance level alarms (e.g. OSHA PEL) and false alarms due to environmental contaminants (e.g. smoke, fuels, diesel exhaust). This prototype sensor technology fills an unmet need for the first responder and is adaptable for the incorporation of new sensors in the future. Figure 1

CFD simulations of wind flow and mean surface pressure for buildings with balconies: Comparison of RANS and LES

Façade geometrical details can substantially influence the near-façade airflow patterns and pressures. This is especially the case for building balconies as their presence can lead to multiple separation and recirculation areas near the façades and hence large changes in surface pressure distribution. Computational fluid dynamics (CFD) has been widely used to investigate the impact of building balconies, mainly based on the steady Reynolds-averaged Navier-Stokes (RANS) approach. The objective of the present study is to evaluate the performance of steady RANS and large-eddy simulations (LES) in predicting the near-façade airflow patterns and mean surface pressure coefficients (Cp) for a building with balconies for three wind directions θ = 0°, 90°, 180°, where 0° is perpendicular to the façade under study. The evaluation is based on validation with wind-tunnel measurements of Cp. The results show that both RANS and LES can accurately predict Cp on the windward façade for θ = 0° with average absolute deviations of 0.113 and 0.091 from the measured data, respectively. For the other two wind directions, LES is clearly superior. For θ = 90°, the average absolute deviations for RANS and LES are 0.302 and 0.096, while these are 0.161 and 0.038 for θ = 180°. Large differences are found in the computed flow fields on the balcony spaces. Because RANS systematically underestimates the absolute values of both Cp and mean wind speed on the balconies, it is suggested that building design based on RANS might result in excessive ventilation and in too high wind nuisance level.

Quantifying damage contributions from convective and stratiform weather types: How well do precipitation and discharge data indicate the risk?

Convective precipitation is intensifying in many regions, but potential implications of shifts in precipitation types on impacts have not been quantified. Furthermore, risk assessments often focus on rare extremes, but also more frequent hydro‐meteorological events burden private and public budgets. Here synoptic, hydrological, meteorological, and socio‐economic data are merged to analyse 25 years of damage claims in 480 Austrian municipalities. Exceedance probabilities of discharge and precipitation associated with damage reports are calculated and compared for convective and stratiform weather patterns. During April to November, 60% of claims are reported under convective conditions. Irrespective of the weather type, most of the accumulated cost links to minor hazard levels, not only indicating that frequent events are a highly relevant expense factor, but also pointing to deficiencies in observational data. High uncertainty in damage costs attributable to extreme events demonstrates the questionable reliability of calculating low‐frequency event return levels. Significant differences exist among weather types. Stratiform weather types are up to 10 times more often associated with damaging extreme discharge or precipitation, while convective weather shows the highest nuisance level contributions. The results show that changes in convective precipitation are pertinent to risk management as convective weather types have contributed significantly to damage in the past.

Acceptable Noise Levels for Typical Outdoor Leisure Activities

Throughout the Appalachian Mountain chain, entrepreneurs have capitalized on the outdoor sporting experience. Both summer and winter sports such as fly fishing, hiking, skiing and snowboarding are very popular. One popular emerging activity is skeet, trap, and sporting clays shooting. Major tourist enterprises are developing this opportunity for both tourists and the local residents. To meet the increasing demand, ranges are being constructed throughout the region from Alabama to Maine. Within North Carolina that are approximately 12 ranges, with an additional 10 in east Tennessee. Although these activities have had few opponents, sporting clays establishments have received an insignificant number of complaints that the noise level is above the noxious level. A research experiment was designed to test noise levels at one sporting clays course situated near a vacation resort. The first phase of this experiment determined that the noise levels at the source from 12 and 20 gauge shotguns were insignificant. The allowable rounds used are the standard reduced load target load. At the source there was a significant difference between trap (85.85 dBA) and skeet (74.95 dBA). At the closest guest location (second phase) 333 samples were taken between August 2015 and March 2016. The noise level averaged 53.7 dBA (σ = 7.43dBA). During the third phase (January to March 2016) 44 samples were obtained at the main resort lodging site. At Site 2 the noise level averaged 31.9 dBA (σ = 5.45). The fourth and final phase of this study was to determine the noise levels at the closest guest location for each of the 12 sporting clays stations. Ninety-six samples (8 per station) were collected in October 2016. The average noise level was 53.0 dBA (σ 4.19 dBA). An analysis at the statistical confidence level of 97.5% was conducted. First all stations were analyzed in a pairwise comparison analysis. Stations that were not significantly different from one another were combined. Thus the 12 stations were reduced to three combined stations. The analysis determined that the noise level from stations 1 through 5 (48.9dBA, σ =1.50 dBA) was significantly lower than from the other stations. Next loudest was the combinations of stations 6, 7, 10, and 11 (54.1 dBA, σ = 1.69). The last loudest combination was stations 8, 9, and 12 (58.6 dBA, σ = 1.50 dDA). Thus there was a difference of 9.7 dBA between the lowest and the loudest station. Since every 5 dBA difference equates to 2 to 3 times louder, depending on frequency, the loudest station is approximately 4 to 6 times louder that the lowest noise level. However, all stations are below the OSHA Standard. With an annoyance level (60.0 dBA) for the guest activity, the gunshots are less than the nuisance level and significantly less than the permissible level. The few complaints about the noise levels are not supported by the noise level data. A logical conclusion is that the objection is the act of shooting and not the noise level of the shotgun’s sharp or impact report. Potential solutions might be to examine stations 8, 9, and 12 and considering possible relocation, orientation, or emplacement of a thick tree barrier to absorb the reports. Regression analysis was used to develop a highly significant model to predict noise levels with the variables collected. However, this will not solve the complaints from those who object to reports under any circumstance.

From the extreme to the mean: Acceleration and tipping points of coastal inundation from sea level rise

AbstractRelative sea level rise (RSLR) has driven large increases in annual water level exceedances (duration and frequency) above minor (nuisance level) coastal flooding elevation thresholds established by the National Weather Service (NWS) at U.S. tide gauges over the last half‐century. For threshold levels below 0.5 m above high tide, the rates of annual exceedances are accelerating along the U.S. East and Gulf Coasts, primarily from evolution of tidal water level distributions to higher elevations impinging on the flood threshold. These accelerations are quantified in terms of the local RSLR rate and tidal range through multiple regression analysis. Along the U.S. West Coast, annual exceedance rates are linearly increasing, complicated by sharp punctuations in RSLR anomalies during El Niño Southern Oscillation (ENSO) phases, and we account for annual exceedance variability along the U.S. West and East Coasts from ENSO forcing. Projections of annual exceedances above local NWS nuisance levels at U.S. tide gauges are estimated by shifting probability estimates of daily maximum water levels over a contemporary 5‐year period following probabilistic RSLR projections of Kopp et al. (2014) for representative concentration pathways (RCP) 2.6, 4.5, and 8.5. We suggest a tipping point for coastal inundation (30 days/per year with a threshold exceedance) based on the evolution of exceedance probabilities. Under forcing associated with the local‐median projections of RSLR, the majority of locations surpass the tipping point over the next several decades regardless of specific RCP.

Mechanical grooming and beach award status are associated with low strandline biodiversity in Scotland

Beach grooming and beach award status are both shown to be associated with low macroinvertebrate taxon richness in Scotland. Previous studies in California have revealed that mechanical raking to remove wrack from sandy beaches has negative ecological consequences for coastal ecosystems. In the current study the presence and absence of eight common taxa that inhabit beached wrack on sandy beaches in Scotland was assessed at 60 sites, 24 of which were groomed and 29 of which were in receipt of a beach award. On average 4.86 of the eight taxa were found to be present on ungroomed beaches, whereas only 1.13 taxa were present on groomed beaches. Thus, beach grooming seems to be having a major effect on the biodiversity of beach macroinvertebrates in Scotland. Fewer macroinvertebrate taxa were also found on award (1.5) compared to non-award (4.38) beaches. It was also revealed that award beaches were much more likely to be groomed than non-award beaches, with 69% of award beaches surveyed being groomed compared to only 6% of non-award beaches. This pattern is surprising as the awarding bodies discourage the removal of seaweed and regulations state that beached wrack should only be removed if it constitutes a nuisance. It is concluded that award status, not nuisance level, has the main factor driving most beach grooming and that this has resulted in the substantial loss of macroinvertebrate biodiversity from award beaches in Scotland. In conclusion it is shown that beach grooming has a substantial negative impact upon strandline macroinvertebrate biodiversity in Scotland and that grooming is much more likely to occur on award beaches.

Counterinsurgency in Modern Warfare (review)

Reviewed by: Counterinsurgency in Modern Warfare Raymond Callahan Counterinsurgency in Modern Warfare. Edited by Daniel Marston and Carter Malkasian. New York: Oxford University Press, 2008. ISBN 978-1-84603-281-3. Maps. Bibliograpy. Index. Pp. 304. $27.95. This collection is both important and timely. Insurgency (or guerrilla warfare or low-intensity operations or whatever label du jour is applied) is the oldest form of warfare on the planet – the natural response of those who cannot, for whatever reason, directly confront the forces of their enemies. Despite this fact, regular armies have rarely been prepared to deal with irregular foes and usually begin by first stigmatizing them as outlaws, bandits, and/or terrorists and then making the fateful assumption that soldiers prepared to fight and win conventional battles will have little difficulty in defeating such opponents. Only after applying inappropriate tactics and, all too often, inflicting self-defeating brutalities on circumambient civilians, have a few armies realized that new approaches are needed. Even fewer have actually succeeded after years of effort in eradicating or reducing to nuisance level the insurgencies they had so blithely assumed would be easily crushed. A more common dénouement is bloody and expensive failure. The sequence has repeated itself so often that it raises the question of whether there is something in the DNA of regular armies that predisposes them to fail repeatedly in the face of the irregular – and poses as well the related question of whether and how the cycle can be broken. Daniel Marston and Carter Malkasian, who have both studied insurgencies as scholars and advised British and American units on counterinsurgency issues, have taken an historical approach, assembling a team of contributors to profile counterinsurgency campaigns from the U.S. effort in the Philippines after we had assumed the "White Man's Burden" in 1898 (analyzed by Anthony Joes) to the on-going struggles in Iraq (Malkasian) and Afghanistan (Marston). It is common in works with multiple authors – and this has thirteen – to note some (and often quite considerable) variability between chapters . This collection, however, is both individually strong and quite consistent, doubtless because of careful work by the editors, and thus allows certain themes to be followed for a century and more. As case study succeeds case study, those themes are continually underlined: [End Page 331] the almost universal initial failure to understand the nature of the problem, which is that firepower may be necessary but is never sufficient; if willingness to shoot was the sole criteria for success, the German counterinsurgency effort in Russia (Peter Lieb), would have been a dazzling triumph. Far more important are two other recurring themes: the inescapable political dimension to counterinsurgency and the central role played by police work and intelligence gathering. All of this makes the management of such a campaign both very complex and exceedingly difficult – perhaps that is why there have been so few successes. It is worth being reminded that the two British campaigns that did end successfully – Malaya (Richard Stubbs) and the thirty- year war in Ireland recently,one hopes, concluded (Richard Iron) – both involved a great deal of trial and error before a winning formula was found, and that success in one counterinsurgency campaign does not mean that an army (or a nation) will win the next. It was less than a decade after the end of the Malayan Emergency – the classic victory over insurgents – that the British had a complete failure in Aden (Jonathan Walker). Another key theme illustrated over and over in this collection – and one that answers both the question about the repetition of failure and that about how to break the cycle – is that political and military institutions never remember unless they carefully arrange to remember. Even well-crafted manuals will not necessarily prevail against the forces of institutional inertia – or self-interested amnesia. This fine collection, handsomely produced by a publisher who understands that to study military history one needs maps, ought to be widely read by students of war, soldiers, politicians – and the pontificators of the op-ed page and Sunday morning television. [End Page 332] Raymond Callahan Emeritus, University of Delaware Newark, Delaware Copyright © 2009 The Society for Military History

Nuisance level of a voice call

In our everyday life, we communicate with many people such as family, friends, neighbors, and colleagues. We communicate with them using different communication media such as email, telephone calls, and face-to-face interactions. While email is not real-time and face-to-face communications require geographic proximity, voice and video communications are preferred over other modes of communication. However, real-time voice/video calls may create nuisance to the receiver. In this article, we describe a mathematical model for computing nuisance level of incoming voice/video calls. We computed the closeness and nuisance level using the calling patterns between the caller and the callee. To validate the nuisance model, we collected cell phone call records of real-life people at our university and computed the nuisance value for all voice calls. We validated the nuisance levels using the feedback from those real-life people. Such a nuisance model is useful for predicting unwanted voice and video sessions in an IP communication network.

Tolerance Thresholds for Aedes albopictus and Aedes caspius in Italian Urban Areas

With nuisance mosquito species, the goal of integrated pest management is to keep mosquito density below a tolerance level that is often set by economic, ecological, and political factors. This study compares actual human annoyance, as measured by a phone survey, with several measures of mosquito abundance, in order to determine a threshold that is both relevant and practical. The efficiency of CO2-baited traps, container index (CI), and oviposition traps for monitoring Aedes albopictus, and CO2-baited traps for monitoring Aedes caspius, was evaluated. CO2-baited traps were confirmed to be of low efficiency in Ae. albopictus collection, while correlation matrices showed a good relationship between CI and the number of eggs collected (R = 0.91), and between number of eggs and phone-survey nuisance level estimates (R = 0.88). Correlation between CI and phone-survey nuisance levels was slightly lower (R = 0.78). We found a close relationship between the nuisance level declared by residents and mosquito captures obtained with CO2-baited traps (Ae. caspius) and ovitraps (Ae. albopictus). An equation is presented to estimate annoyance according to dwelling characteristics and to the presence of children in the family.

Development of emergency response planning guidelines (ERPGs)

Emergency Response Planning Guidelines (ERPGs) are airborne concentrations of chemicals that have been evaluated for three levels of emergency response. These are a nuisance level, and level that would affect egress from an exposure or a level that is near, but below a life threatening concentration. The ERPG is a volunteer committee of the American Industrial Hygiene Association that is comprised of industrial hygienists and toxicologists. This paper describes the history of emergency response guidelines and process of the evaluation.

Process of invasiveness among exotic tunicates in Prince Edward Island, Canada

Over the past decade, four exotic tunicates (Styela clava, Ciona intestinalis, Botrylloides violaceus and Botryllus schlosseri) have been reported in the Brudenell estuary in Prince Edward Island (PEI), Canada. Styela clava was the first exotic tunicate to arrive in 1997, rapidly establishing, spreading, invading, and eventually becoming a nuisance in several estuaries of PEI. In the Brudenell estuary, S. clava remained the only exotic nuisance tunicate until 2003. In the fall of 2004, the vase tunicate C. intestinalis, was reported in low abundance, followed by the two colonial species, B. schlosseri and B. violaceus, reported in the spring of 2005. The abundance of C. intestinalis rapidly increased post-introduction, eventually replacing S. clava as the foremost nuisance species on mussel farms in the estuary. To date, C. intestinalis continues to colonize this estuary at epidemic proportions, resulting in the continuing drop of S. clava abundance. The current abundance of C. intestinalis is estimated at 5 cm−2, which is similar to S. clava abundance at its height in 2003. The 2006 abundance of S. clava is estimated to have fallen to near 0 cm−2. The dominance of C. intestinalis as a fouling organism on mussel farms is considered a serious threat to this aquaculture industry, mainly due to its unmanageable weight. The process of the detection, establishment, invasiveness, and eventual rise to nuisance level of exotic tunicates in the Brudenell River is presented.

Interactions between flow, periphyton, and nutrients in a heavily impacted urban stream: implications for stream restoration effectiveness

Urban stream restoration is a very complex task due largely to the interactions between the physical, chemical, and biological stream components. Because of these interactions, restoring only a single component to a more natural state could have a negative affect on stream health. We studied pre-restoration interactions between hydrology, nutrients, and periphyton in a stream where wastewater effluent and a highly developed urban watershed dominated stream flow. Floods capable of scouring all visible periphyton from the stream were produced from rainfall events as small as 1.3 cm and created 47 periphyton biomass reset events during our 22-month study period. Despite these disturbances, periphyton biomass rapidly accumulated throughout the stream and reached nuisance levels after 5 days of growth during every season. Floods did, however, severely limit the occurrence of steady-state assemblages, which attained biomass levels 30 times the nuisance level. Although the high frequency of floods did not prevent nuisance levels of periphyton, it did allow more edible early stage periphyton assemblages to become far more common than late-stage, less edible assemblages. In the case of the stream studied, a successful restoration strategy must consider coupled processes relating to hydrology, chemistry, and biota.

Predicting the Frequencies of High Chlorophyll Levels in Florida Lakes from Average Chlorophyll or Nutrient Data

ABSTRACT An alternative to using average concentrations of phytoplankton chlorophyll in setting lake management goals is to use the frequency that chlorophyll concentrations exceed an established nuisance level. We analyzed 1473 lake-years of data on 438 Florida lakes to develop a series of tables that can be used to predict the frequencies that phytoplankton chlorophylls will exceed concentrations of 10, 20, 30, 40, 50, and 60 mg m−3 in Florida lakes based on the annual average concentrations of chlorophyll, total phosphorus, or total nitrogen. Different tables were created for lakes grouped by TN/TP ratios of >17, <17 but >10, and <10. These tables can be directly applied towards setting lake management goals for those Florida lakes that lack sufficient data to construct their own bloom frequency curves.

Increasing flood risk and wetland losses due to global sea-level rise: regional and global analyses

To develop improved estimates of (1) flooding due to storm surges, and (2) wetland losses due to accelerated sea-level rise, the work of Hoozemans et al. (1993) is extended to a dynamic analysis. It considers the effects of several simultaneously changing factors, including: (1) global sea-level rise and subsidence; (2) increasing coastal population; and (3) improving standards of flood defence (using GNP/capita as an “ability-to-pay” parameter). The global sea-level rise scenarios are derived from two General Circulation Model (GCM) experiments of the Hadley Centre: (1) the HadCM2 greenhouse gas only ensemble experiment and (2) the more recent HadCM3 greenhouse gas only experiment. In all cases there is a global rise in sea level of about 38 cm from 1990 to the 2080s. No other climate change is considered. Relative to an evolving reference scenario without sea-level rise, this analysis suggests that the number of people flooded by storm surge in a typical year will be more than five times higher due to sea-level rise by the 2080s. Many of these people will experience annual or more frequent flooding, suggesting that the increase in flood frequency will be more than nuisance level and some response (increased protection, migration, etc.) will be required. In absolute terms, the areas most vulnerable to flooding are the southern Mediterranean, Africa, and most particularly, South and South-east Asia where there is a concentration of low-lying populated deltas. However, the Caribbean, the Indian Ocean islands and the Pacific Ocean small islands may experience the largest relative increase in flood risk. By the 2080s, sea-level rise could cause the loss of up to 22% of the world's coastal wetlands. When combined with other losses due to direct human action, up to 70% of the world's coastal wetlands could be lost by the 2080s, although there is considerable uncertainty. Therefore, sea-level rise would reinforce other adverse trends of wetland loss. The largest losses due to sea-level rise will be around the Mediterranean and Baltic and to a lesser extent on the Atlantic coast of Central and North America and the smaller islands of the Caribbean. Collectively, these results show that a relatively small global rise in sea level could have significant adverse impacts if there is no adaptive response. Given the “commitment to sea-level rise” irrespective of any realistic future emissions policy, there is a need to start strategic planning of appropriate responses now. Given that coastal flooding and wetland loss are already important problems, such planning could have immediate benefits.

Periphyton removal related to phosphorus and grazer biomass level

Summary1. The proliferation of nuisance periphyton in enriched streams may be dependent on the biomass of the grazing macroinvertebrates present. In the present study, the effectiveness of grazer size and biomass in controlling periphyton and the extent to which grazing effectiveness was affected by enrichment level were determined.2. Two sets of experiments with two caddisfly grazers were conducted in laboratory channels during spring and summer 1995 and 1996. The first set tested the combined effect of phosphorus enrichment and grazing, while the second set tested the effect of variable grazer biomass on periphyton biomass.3. Grazing reduced periphyton biomass in excess of 80%, compared to ungrazed controls. Grazers were equally effective in controlling filamentous green algae, Stigeoclonium, diatoms and small colonial greens. Near complete removal of periphyton biomass by grazing occurred at even at the lowest grazer biomass level (750 mg m−−2, i.e. approximately one‐third of natural levels).4. Grazing controlled periphyton biomass more than did enrichment with soluble reactive phosphorus (SRP).5. Grazing rates in the phosphorus‐grazing interaction experiments averaged about 6 mg chl a g invertebrate−−1 day−−1, which was similar to past work in these channels and elsewhere, while rates were about five‐fold higher in the variable grazer biomass experiments.6. Simulating effects of SRP and grazing with a calibrated model suggests that higher SRP levels would be necessary to exceed a nuisance periphyton biomass level if grazers were present. However, if grazer biomass was more than 1500 mg m−−2, a nuisance level would probably not be exceeded at any SRP.

COST COMPARISON BETWEEN CESSPOOL AND SANITARY SEWERAGE SYSTEMS IN SAUDI URBAN AREAS1

ABSTRACT: Extensive use is made of on‐site wastewater disposal systems of cesspools due to the absence of a sanitary sewerage system in Saudi urban areas. This system has caused the groundwater table to rise to a public nuisance level. A health risk has also evolved. There are several infrastructural, environmental, and social impacts from this, resulting in great financial losses. Examples are: surface water flooding, damage to foundations of buildings and asphalt street pavements, flooded basements and added construction costs required for excavation, dewatering, insulation materials, and special cements. Most of these costs are indirectly being paid by the private and public sectors. This study compares the estimated costs of damage and losses with the estimated costs of building, operating, and maintaining sanitary sewerage systems in the cesspool‐served areas. The annual cost of the cesspool system, depending on the severity of the adverse impacts, ranges from 2.2 to 4.4 times the annual cost of the sanitary sewerage system. Remedies for these impacts are very expensive, and delays in the implementation of the sanitary sewerage facility will make the damage recovery more expensive, and in some cases, impossible. Thus, it is recommended that highest priority to be given to the sanitary sewerage systems in Saudi urban areas.

Motivation à l'acquisition et à l'utilisation des moustiquaires imprégnées dans une zone à paludisme stable au Burundi

In Burundi, the purchase, acceptance and utilization of impregnated bed nets sold at a promotion price (2 $US) were evaluated in a stable malaria area (South-Imbo, district of Nyanza Lac) where this method of protection was previously unknown to the inhabitants. The sale of the impregnated nets differed between the administrative subdivisions (so-called 'collines') of the area with a coverage varying from 10 to 70% of families. Moreover, in one of these collines with a high overall coverage rate (62%) a difference was also found between the three administrative regions (so-called 'sous-collines') which were socially and economically similar. However, these sous-collines (SC) differed in their geographical location and were found at different altitudes. The real coverage corresponding with the percentage of families showing at least one installed bed net, was calculated for each SC. This coverage was 77% in the SC-1 situated in the low wet area and decreased gradually to 14% in the SC-3 at the highest altitude. The purchase of a bed net does not necessarily mean that people will use them. About 30% of the bed nets bought at the promotion price could not be found and most of them were resold in the neighbouring country (Tanzania). Between 7 (SC-I) and 47% (SC-3) of the bed nets were still packed and not in use. The motivation for buying and using impregnated nets appears to depend essentially on the nuisance level caused by mosquitoes, as shown by the abundance of the mosquitoes in the SC-1 situated in the low wet area (75 bites/man/night) compared to that observed in the SC-2 located at a higher altitude (i bite/man/night). The authors conclude that appropriate health education and information should be developed and promoted by health staff, local authorities and teachers in order not only to improve comfort by decreasing the insect nuisance, but also to decrease the considerable malaria burden in the community.

Prediction of nuisance periphytic biomass: A management approach

Model predictions of periphyton biomass, as a function of ambient SRP concentration, were compared against observed biomass accrual on natural and artificial substrates in the Spokane River, Washington. A range in biomass was predicted based on uncertainties due to temperature, velocity, accumulation period and an empirical growth constant. Only 8 of 47 observed biomass values exceed the lowest biomass predictions, which supports the contention that the model represents the maximum potential biomass. Using the SRP concentration that would produce a threshold nuisance biomass (150–200 mg ch α/m 2), an approach is proposed for controlling the stream distance for which periphytic biomass exceeds the nuisance level. For the Spokane River, critical distance with biomass exceeding 200 mg chl α/m 2 may exceed 10 km unless SRP is held below 10 μg/l.

Factors affecting resistance to insecticides in house-flies, Musca domestica L. (Diptera: Muscidae). I. Long-term control with bioresmethrin of flies with strong pyrethroid-resistance potential

AbstractThe assumption that by minimising contact with pyrethroids, satisfactory control of Musca domestica L. could be retained without eliciting resistance was tested on a pig farm in southern England where permethrin had failed through rapid development of resistance. Flies were satisfactorily controlled in enclosed buildings for 12 months by space spraying bioresmethrin (2 mg a.i./m3) at approximately fortnightly intervals when numbers reached an arbitrary nuisance level. Throughout this period, bioassays revealed no increase in tolerance of pyrethroids, although selection experiments in the laboratory confirmed the strong pyrethroid-resistance potential of the fly population. Thus effective control can be retained in spite of strong resistance potential when non-persistent insecticides are used intermittently. The results are discussed in the light of a published theoretical study of the influence of pesticide persistence on the evolution of resistance.