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BACKGROUND Evidence is urgently needed to support treatment decisions for children with multisystem inflammatory syndrome (MIS-C) associated with severe acute respiratory syndrome coronavirus 2. METHODS We performed an international observational cohort study of clinical and outcome data regarding suspected MIS-C that had been uploaded by physicians onto a Web-based database. We used inverse-probability weighting and generalized linear models to evaluate intravenous immune globulin (IVIG) as a reference, as compared with IVIG plus glucocorticoids and glucocorticoids alone. There were two primary outcomes: the first was a composite of inotropic support or mechanical ventilation by day 2 or later or death; the second was a reduction in disease severity on an ordinal scale by day 2. Secondary outcomes included treatment escalation and the time until a reduction in organ failure and inflammation. RESULTS Data were available regarding the course of treatment for 614 children from 32 countries from June 2020 through February 2021; 490 met the World Health Organization criteria for MIS-C. Of the 614 children with suspected MIS-C, 246 received primary treatment with IVIG alone, 208 with IVIG plus glucocorticoids, and 99 with glucocorticoids alone; 22 children received other treatment combinations, including biologic agents, and 39 received no immunomodulatory therapy. Receipt of inotropic or ventilatory support or death occurred in 56 patients who received IVIG plus glucocorticoids (adjusted odds ratio for the comparison with IVIG alone, 0.77; 95% confidence interval [CI], 0.33 to 1.82) and in 17 patients who received glucocorticoids alone (adjusted odds ratio, 0.54; 95% CI, 0.22 to 1.33). The adjusted odds ratios for a reduction in disease severity were similar in the two groups, as compared with IVIG alone (0.90 for IVIG plus glucocorticoids and 0.93 for glucocorticoids alone). The time until a reduction in disease severity was similar in the three groups. CONCLUSIONS We found no evidence that recovery from MIS-C differed after primary treatment with IVIG alone, IVIG plus glucocorticoids, or glucocorticoids alone, although significant differences may emerge as more data accrue. Copyright © 2021 Massachusetts Medical Society.

In this chapter, a combined forward osmosis (FO) and reverse osmosis (RO) process for mining wastewater treatment is discussed. Water interactions in mining process, wastewater characteristic treatment methods adopted, and the research technology gaps are briefly discussed. A lab-scale integrated FO-RO was developed to establish the proof of concept in applying this technology for mine water treatment. The integrated system has been tested under extended operation with various mine waters. The FO combined with RO could minimize the number of pretreatment steps required for the RO. Our results indicate that this technology can reduce the brine volume by at least 80% and recover a consistent quality reusable water. A pilot scale FO-RO with a capacity of 1 m3/day was designed and built, incorporating two different types of FO membranes. The study showed that this process can potentially offer a significant reduction in energy use, chemical use, piping infrastructure, and operating costs in desalinating mine water and the success of this technology is in the efficient process configuration and FO membrane module configuration, membrane chemistry and structure.

An experimental approach to road mitigation that maximizes inferential power is essential to ensure that mitigation is both ecologically-effective and cost-effective. Here, we set out the need for and standards of using an experimental approach to road mitigation, in order to improve knowledge of the influence of mitigation measures on wildlife populations. We point out two key areas that need to be considered when conducting mitigation experiments. First, researchers need to get involved at the earliest stage of the road or mitigation project to ensure the necessary planning and funds are available for conducting a high quality experiment. Second, experimentation will generate new knowledge about the parameters that influence mitigation effectiveness, which ultimately allows better prediction for future road mitigation projects. We identify seven key questions about mitigation structures (i.e., wildlife crossing structures and fencing) that remain largely or entirely unanswered at the population-level: (1) Does a given crossing structure work? What type and size of crossing structures should we use? (2) How many crossing structures should we build? (3) Is it more effective to install a small number of large-sized crossing structures or a large number of small-sized crossing structures? (4) How much barrier fencing is needed for a given length of road? (5) Do we need funnel fencing to lead animals to crossing structures, and how long does such fencing have to be? (6) How should we manage/manipulate the environment in the area around the crossing structures and fencing? (7) Where should we place crossing structures and barrier fencing? We provide experimental approaches to answering each of them using example Before-After-Control-Impact (BACI) study designs for two stages in the road/mitigation project where researchers may become involved: (1) at the beginning of a road/mitigation project, and (2) after the mitigation has been constructed; highlighting real case studies when available.

Local government planning agencies play an important role in conserving biodiversity in human-altered landscapes. Such agencies frequently have a limited knowledge of wildlife biology and few resources to carry out research, and therefore require simple, practical guidelines for biodiversity conservation. We propose a landscape design framework for biodiversity conservation that is sequential, prescriptive, and supported by current landscape ecological science. Unlike existing guidelines, our framework can be implemented in any given landscape using only land cover data and it explicitly considers constraints on land use planning. The steps of our framework, in the order in which they should be implemented are: (1) select land cover data and decide which land cover classes constitute unaltered or altered land covers; (2) list the constraints on land use planning (e.g., economic, social) that exist for the landscape; (3) maximize the total amount and diversity of unaltered land cover, especially near water; (4) minimize human disturbance within altered land cover, especially near water; and (5) aggregate altered land covers associated with high-intensity land uses, especially away from water. We illustrate the utility of our approach by applying it to a hypothetical landscape and comparing the outcome to those from the application of traditional ecological guidelines to inform land use planning.

In habitats disturbed by anthropogenic noise, acoustically communicating species may develop behavioral responses that help them transmit information and overcome signal masking. We studied four anuran species breeding in wetlands, ponds, and ditches near a highway in eastern Ontario, Canada, to test whether they called more often when traffic noise intensity was lower, and stopped calling when the noise intensity increased (i.e., gap calling behavior). We made call recordings between April and July 2011, and compared the traffic noise intensity (sound pressure level) between times when the anurans were calling and times when they were not calling. We found that the two species with the highest call peak frequency (American toad, gray treefrog) called randomly with regard to traffic noise intensity. In contrast, the two species with the lowest call peak frequency (green frog, bullfrog) called more often when traffic noise intensity was low. The behavioral response in the two latter species likely represents a short-term strategy that enhances their signal-to-noise ratio thereby increasing the chance of effective communication. Our results support predictions derived from the acoustic adaptation hypothesis: low-frequency signals are more prone to be masked by anthropogenic noise and therefore require behavioral adjustments (in this study gap-calling behavior) to ameliorate this effect.

Roads are linked to population declines in amphibians, primarily due to road mortality. Culvert-type ecopassages, along with fencing to direct animals to the passage, have been used to mitigate these impacts. However, the effectiveness of the ecopassage itself, independent of the associated mitigation fencing, is largely untested. In regions with heavy snowfall, long-term maintenance of amphibian-proof fencing is extremely costly. Therefore, it is important to know whether ecopassages alone (without fencing) mitigate amphibian mortality. We used a Before-After-Control-Impact design to experimentally test the hypothesis that pre-existing drainage culverts of the type typically used to mitigate road effects on herptiles mitigate anuran road mortality. Grates were installed at both ends of 6 culverts to exclude anurans from the culverts. At an additional 4 sites fencing was installed on either side of culverts on both sides of the road, to keep anurans off the road. Ten control culverts were left u...

Background The high diagnostic accuracy of adenosine stress cardiac magnetic resonance (AS-CMR) for detecting coronary artery stenoses, with high sensitivity and specificity, is well documented. Prognostic data, particularly in non-low risk study populations and for greater than 12months of follow up, is however lacking or variable in its findings. We present prognostic data, in an intermediate cardiovascular risk cohort undergoing adenosine stress perfusion CMR, over approximately 2years of follow up. Methods The study population comprised 362 patients referred for a clinically indicated stress CMR and included patients with proven coronary artery disease (CAD; n=157) or unknown CAD status, yet an intermediate cardiovascular risk profile (n=205). Perfusion imaging was performed at stress (adenosine 140μg/kg/min) and rest on a 1.5T system. Patient records and state-wide hospital databases were reviewed. Major adverse cardiac events — death, myocardial infarction, revascularisation or ischaemic hospitalisation — were evaluated over a median follow up of 22months. Results Of the 362 cases, 90 had a stress perfusion CMR positive for ischaemia and experienced a MACE rate of 24%. Of the 272 negative CMR scans, 225 were also negative for late gadolinium enhancement, and in this group MACE was encountered in only 6 (2.7%) patients. Accordingly a negative stress CMR afforded a freedom from MACE of 97.3%. Freedom from death/myocardial infarction was 99.6%. Conclusions In patients with confirmed coronary artery disease or at intermediate risk for cardiovascular events, a negative stress perfusion CMR is associated with an excellent prognosis over nearly 2years of follow up.

We previously found that males of two anuran species – Hyla versicolor and Rana clamitans – alter their mating calls in response to traffic noise. To test whether these alterations compensate for an effect of traffic noise on mate attraction, we (1) recorded a male calling at a quiet site; (2) played traffic noise at the same male and recorded its altered call; (3) used these recordings to attract females to a trap at sites either with or without broadcast traffic noise. The calls produced without traffic noise attracted fewer females when they were played at sites with traffic noise than when they were played at sites without noise. However, the calls of the same individuals produced with traffic noise attracted as many females at sites with noise as at sites without noise, and they attracted as many females as did the call of the same male made without noise and played at sites without noise (the ‘natural’ situation). Therefore, for these species, traffic noise does not affect mate attraction; males change their calls to compensate for a potential effect of traffic noise on mate attraction. A third species – Bufo americanus – does not alter its call in response to traffic noise, and its call made in the absence or presence of traffic noise was equally able to attract females in the absence or presence of traffic noise, indicating that traffic noise does not negatively affect mate attraction. Therefore, it appears that traffic noise does not negatively affect mate attraction in these three species of anurans. We suggest that, if our results apply to anurans in general, the previously documented negative effects of roads on anuran populations are likely caused mainly by road mortality. If this is true, road mitigation for anurans should focus mainly on reducing this mortality.

Accurate assessment of aortic annular dimensions is essential for successful transcatheter aortic valve implantation (TAVI). Annular dimensions are conventionally measured in mid-systole by multidetector computed tomography (MDCT), echocardiography and angiography. Significant differences in systolic and diastolic aortic annular dimensions have been demonstrated in cohorts without aortic stenosis (AS), but it is unknown whether similar dynamic variation in annular dimensions exists in patients with severe calcific AS in whom aortic compliance is likely to be substantially reduced. We investigated the variation in aortic annular dimensions between systole and diastole in patients with severe calcific AS. Patients with severe calcific AS referred for TAVI were evaluated by 128-slice MDCT. Aortic annular diameter was measured during diastole and systole in the modified coronal, modified sagittal, and basal ring planes (maximal, minimal and mean diameters). Differences between systole and diastole were analysed by paired t test. Fifty-nine patients were included in the analysis. Three of the five aortic dimensions measured increased significantly during systole. The largest change was a 0.75 mm (3.4%) mean increase in the minimal diameter of the basal ring during systole (p = 0.004). This corresponds closely to the modified sagittal view, which also increased by mean 0.42 mm (1.9%) during systole (p = 0.008). There was no significant change in the maximal diameter of the basal ring or the modified coronal view during systole (p > 0.05). There is a small magnitude but statistically significant difference in aortic annulus dimensions of patients with severe AS referred for TAVI when measured in diastole and systole. This small difference is unlikely to alter clinical decisions regarding prosthesis size or suitability for TAVI.

Summary 1. The effects of roads on wildlife populations are widespread and well documented. Many studies have shown that bird abundance, occurrence and species richness are reduced near roads, with the largest reductions where traffic levels are high. Negative correlations have been reported between bird richness ⁄ abundance and traffic noise but the possible causes of road effects are inter-correlated. It is important to disentangle the different effects so that appropriate mitigation measures can be implemented. 2. We tested the hypothesis that traffic noise is a key negative effect by testing three predictions: (i) bird richness ⁄ abundance should reach a maximum at the same distance from roads that traffic noise reaches a minimum; (ii) the effect of traffic noise on bird richness ⁄ abundance should be stronger than the effect of distance from the road on bird richness ⁄ abundance; and (iii) sites with more traffic noise at a given distance from the road should show lower bird richness ⁄ abundance than sites with less traffic noise at the same distance. 3. We collected breeding bird occurrence and traffic noise data along twenty 600-m transects perpendicular to roads at 10 high-traffic road sites. 4. Traffic noise decreased and bird species richness increased with increasing distance from the roads. However, none of the predictions derived from the traffic noise hypothesis was supported. 5. Synthesis and applications. Our results suggest that traffic noise is not the main cause of the negative relationship between bird species richness ⁄ abundance and proximity to roads. Instead, traffic mortality may be the main mechanism causing this relationship. We suggest that mitigation of road impacts on birds should focus mainly on reducing mortality rather than reducing traffic noise. In particular, engineering road surfaces, tyres and vehicle engines to reduce noise would not mitigate road effects; instead, structures to keep birds away from roads or force them to fly above the traffic would be more effective.

Many species use acoustic signals to attract mates, and such signals can be degraded by anthropogenic noise. Anuran abundance has been shown to be negatively correlated with road traffic which could be due in part to the interruption of mate attraction by traffic noise. However, this impact could be small if anurans can alter their vocalization characteristics to avoid masking of their calls by traffic noise. We predicted that: (i) anuran vocalization characteristics (dominant frequency, mean amplitude and call rate) should be different in areas with different traffic noise levels; (ii) increases in traffic noise can cause immediate changes in amphibian vocalization characteristics; (iii) these altered vocalizations are similar to those at high traffic sites. To test the first prediction we compared vocalizations of four species of anuran at breeding sites in locations with low traffic noise vs. sites with high traffic noise. For the second prediction we broadcast traffic noise at low traffic (quiet) sites, and compared the anuran vocalizations before vs. during the broadcast traffic noise. For the third prediction we compared vocalizations at high traffic sites to those produced at low traffic sites while broadcasting traffic noise. Three species of anurans found at locations with low traffic noise produced vocalizations with different characteristics than individuals of the same species found in locations with high traffic noise. Broadcast traffic noise immediately altered amphibian vocalization characteristics such that they became similar to those of the same species found in locations with high traffic noise. We conclude that plasticity in the vocalizations of anurans allows for the maintenance of acoustic communication in the presence of traffic noise.

Temperature is often an important determinant of species presence and activity patterns, but observations of temperature at fine resolution and broad extents—scales relevant to individual organisms—are rare. We analyzed how biotic and abiotic variables influence ground surface temperature (GST) using high-resolution thermal data for a 1900-ha area of forest and field near Wasaga Beach, Ontario, Canada. Temperature was recorded at 2-h intervals from May to October, 2004 and 2005, from data loggers approximately 300 m apart. At the same sites, we recorded overstory and understory vegetation, elevation, and distances to the nearest road and urban infrastructure. Correspondence Analysis (CA) indicated that thermal conditions varied most strongly seasonally and diurnally. Canonical Correspondence Analysis (CCA) pinpointed which biotic and abiotic variables were related to surface temperature. Canopy cover and leaf litter cover were positively related to cool sites during both cool and warm periods. Si...

The regional response of climate models to small perturbations is shown to be highly dependent on the unperturbed simulation. an experiment in which CO2 concentrations are doubled and sea surface temperatures are enhanced by 2 K has been carried out with two general circulation models which differ considerably in their control climates. the resulting changes in tropical precipitation in each model simulation are related to the increase in atmospheric water vapour which leads to enhanced precipitation in the main regions of low-level atmospheric convergence. Since these regions of convergence occur in slightly different locations in the unperturbed simulations, the distribution of changes is also different. Differences in control simulations must be taken into account when comparing results from different models (for example, on doubling atmospheric CO2); otherwise unduly pessimistic conclusions may be reached concerning the consistency of model results. One may be able to make subjective allowance for the effect of known deficiencies in the unperturbed simulation on the model's response before using the simulated changes in, for example, impact studies. A detailed examination of one of the experiments reveals that the change in precipitation is limited by the heat balance of the atmosphere, and indicates the importance of treating accurately the radiative perturbation due to changes in water vapour. the magnitude of the model's response is shown to be consistent with that found in three-dimensional climate models which include a simple representation of the ocean.

This chapter examines the integration of forward osmosis (FO) with other water treatment methods with a particular focus on integrating FO and reverse osmosis (RO) technologies. It discusses the limitations of RO in relation to the quality of the feed water, in particular for the treatment of mining wastewater. In dry conditions, water management must focus on minimizing dependence on high-quality water. Adapting coal handling and preparation plants and dust suppression to use highly saline water reduces the volume of raw water that needs treatment at mine sites. The chapter presents different modes of integration and examines the advantages and limitations of different hybrid configurations. The hybrid system could potentially eliminate the extensive pretreatment required for conventional RO processes and thereby the overall cost of desalination. The mine site application of hybrid FO-RO technology has yet to be investigated.

While conducting a study of home range and habitat use of the eastern hognose snake (Heterodon platirhinos) in Southern Ontario, we observed both mating and nesting behaviors for this species. Here we describe the active excavation of oviposition sites by H. platirhinos; mating behavior, including multiple copulations of a single female with five males; and philopatry to specific nest sites by multiple individuals in successive years. As our study site is close to the northern limit of this species' range, nest sites may need to be carefully selected to provide a thermal regime warm enough to incubate the eggs. Mean nest temperatures in the field ranged from 23.4 to 26.1 C, while incubation periods ranged from 49 to 63 d.

Strategies to reduce wildlife road mortality have become a significant component of many conservation efforts. However, their success depends on knowledge of the temporal and spatial patterns of mortality. We studied these patterns along the 1000 Islands Parkway in Ontario, Canada, a 37 km road that runs adjacent to the St. Lawrence River and bisects the Algonquin-to-Adirondacks international conservation corridor. Characteristics of all vertebrate road kill were recorded during 209 bicycle surveys conducted from 2008 to 2011. We estimate that over 16,700 vertebrates are killed on the road from April to October each year; most are amphibians, but high numbers of birds, mammals, and reptiles were also found, including six reptiles considered at-risk in Canada. Regression tree analysis was used to assess the importance of seasonality, weather, and traffic on road kill magnitude. All taxa except mammals exhibited distinct temporal peaks corresponding to phases in annual life cycles. Variations in weather and traffic were only important outside these peak times. Getis–Ord analysis was used to identify spatial clusters of mortality. Hot spots were found in all years for all taxa, but locations varied annually. A significant spatial association was found between multiyear hot spots and wetlands. The results underscore the notion that multi-species conservation efforts must account for differences in the seasonality of road mortality among species and that multiple years of data are necessary to identify locations where the greatest conservation good can be achieved. This information can be used to inform mitigation strategies with implications for conservation at regional scales.

James D. Richardson, Michael S. Cunnington, Adam J. Nelson, Julie A. Bradley, Karen S. L. Teo, Stephen G. Worthley, Matthew I. Worthley

Two sensitivity experiments, in which CO2 is doubled and sea-surface temperatures are enhanced, were carried out using a general circulation model to determine the influence of the convective parametrization on simulated climate change. In the first experiment, a non-penetrative “layer-swapping” convection scheme is used; in the second, a penetrative scheme is used. It is found that the penetrative scheme gives the greater upper tropospheric warming (over 4.5 K compared to 4 K) and the greater reduction in upper tropospheric cloud, consistent with recent CO2 sensitivity studies. However, there is a 0.7 Wm−2 greater increase in net downward radiation at the top of the atmosphere in the experiment with the non-penetrative scheme, implying a larger tropical warming which is inconsistent with recent CO2 studies. Other possible explanations for discrepancies between recent studies of the equilibrium climate response to increasing CO2 are considered and discussed. The changes in the atmospheric fluxes of heat and moisture from the tropical continents in the model with the penetrative scheme differ from those found using the non-penetrative scheme, and those in an equilibrium experiment using the penetrative scheme. Thus, changes in circulation may explain the apparent discrepancy in the current experiments, but prescribed sea-surface temperature experiments may not provide a reliable indication of a model's equilibrium climate sensitivity.

Background – It has been proposed that multiple sclerosis (MS) might be a sexually transmitted disorder. There is evidence that seropositivity to herpes simplex virus type 2 (HSV-2) correlates well with the number of sexual partners. Accordingly, a raised overall HSV-2 seroprevalence in MS would lend support to this theory. Materials and methods – Serum from 497 UK subjects with clinically definite MS was tested for antibodies to HSV-2 and compared with matched historical controls from within and outside London, blood donors and genito-urinary medicine (GUM) clinics. Results – The unadjusted MS seropositivity rate was 14%. HSV-2 seroprevalence in MS patients aged 35–64 years was significantly higher overall compared with a non-London general population in an unadjusted comparison. HSV-2 seroprevalence in London MS patients compared with London blood donors was significantly greater irrespective of age, but the MS seropositive rate was lower than GUM clinic attenders. In a logistic regression analysis, increased age, female sex and MS diagnosis all independently increased the odds of seropositivity after adjustment for each other. Conclusion – It is concluded that there is increased likelihood of HSV-2 exposure in patients with MS and this may indicate a higher than average number of partners.

The traditional undergraduate engineering curriculum provides methods of analyzing and creating paper designs, but does much less in teaching design for manufacture and production. The Capstone experience at the University of Idaho uses a mentor-based design process that takes projects from the conceptual stage through creation of functional prototypes. Graduate student mentors in the Idaho Engineering Works (IEWorks) have created a three-session orientation that teaches fundamentals of machining associated with the construction of a small multi-tool. Student feedback recorded in their design journals underscores the benefits of this shop orientation in promoting machine design skills that result in high quality prototypes delivered to industry customers at the end of the course and in fostering a close relationship between mentors and students.

The authors explore the use of third generation echo contrast to define plaque in the ascending aorta and exclude more invasive procedures.

OBJECTIVE: To investigate the prevalence of carcinoma in situ of the testis in a group of oligozoospermic men from infertile couples. DESIGN: A consecutive group of oligozoospermic men from infertile couples were offered bilateral testicular biopsy. The observed prevalence of carcinoma in situ was compared with the expected prevalence of testicular cancer in a corresponding age matched population of Danish men, assuming all untreated cases of carcinoma in situ progress to tumour stage. This calculation was based on data from the Danish Cancer Registry. SUBJECTS: 207 men aged 18-50 years who had sperm density below 10 million/ml in two samples within the previous 2 years or sperm density below 20 million/ml in two samples within the previous 2 years and a history of cryptorchidism or one or two atrophic testicles (orchidometer volume less than 15 cm3), or both. INTERVENTIONS: Bilateral testicular biopsies. MAIN OUTCOME MEASURES: Carcinoma in situ in the biopsy specimen. RESULTS: No case of carcinoma in situ was found among the 207 men. The expected number in a normal age matched population of corresponding size was 0.8. CONCLUSIONS: There is no increase in risk of carcinoma in situ of the testis in moderately oligozoospermic men of couples referred because of infertility.

ejection fraction (EF), aortic valve flow velocity, and myocardial mass were compared pre and post TAVI by paired t-tests. Results: Fourteen patients underwent CMR pre TAVI and at follow up (median 10 months). Mean myocardial mass reduced by 28 g (18%) post TAVI (p< 0.05), with a trend towards reduction in ESV and increase in EF. Velocity encoded flow-derived aortic regurgitation was trivial/mild in 13 and moderate in one patient. Peak aortic flow velocity was notmeasureable in CoreValve recipients (n= 10) due to signal void artefact, but could be assessed following Edwards-Sapien implantation (n= 4). The table shows means± standard errors. EDV (mL) ESV (mL) EF (%) Peak velocity (m/s) Mass (g) Pre-TAVI 150 ± 11 73 ± 11 54 ± 4 4.2 ± 0.1 160 ± 9 Post-TAVI 151 ± 13 69 ± 12 57 ± 5 1.6 ± 0.1 132 ± 9 Conclusions: CMR following TAVI is feasible and provides useful assessment of cardiac structural and functional changes, with a reduction in myocardial mass post TAVI. http://dx.doi.org/10.1016/j.hlc.2012.05.468

The sensitivity of an atmospheric general circulation model to changes in atmospheric water content, soil moisture content, radiation scheme and albedo have been investigated using the Meteorological Office global 11-layer model. Previous integrations had produced excessive rainfall in the Saharan region. This paper reports experiments which show the importance for a good Saharan simulation of the initial atmosphere and soil moisture specifications, of the radiation scheme and of the surface albedo specification. It is shown that a dry Sahara with realistic circulation patterns is simulated only if the surface and atmosphere are initially realistically dry and the model's longwave radiation is dependent on atmospheric water vapour content. With a moist atmosphere, introduced either initially or by rapid evaporation from a wet soil, or by using a radiation scheme without water vapour dependence, there is increased net downward radiation which enhances ascent and convective activity and leads eventually to excessive rainfall in the desert region with a reversal of the usual circulation pattern to give 700 mb westerly winds at 5°–15°N associated with a cyclonic circulation over the Saharan region which draws in moist air from the south. As expected from Charney's hypothesis on the maintenance of deserts, the use of more realistic albedos tends to transfer rainfall from regions of higher albedo (e.g. deserts) to regions of lower albedo (e.g. forests). An extension of Charney's hypothesis to include moisture is proposed in which any increase in diabatic heating, whether due to reduced albedo or increased moisture availability, must be compensated by increased cold advection; in the tropics this typically occurs through ascent of potentially colder air leading to rainfall if the air is moist enough or the ascending layer sufficiently deep. Some implications of the possibility of two distinct summer circulation patterns for the theory of past North African climate are discussed.

In the Caspian Sea region of Iran asthma seems closely related to house dust allergy. Since a high proportion of house dust sensitive patients appear to be sensitive to house dust mites, an investigation was carried out to determine the occurrence, distribution and abundance of these species in Iranian house dust in order to assess their role and clinical importance in house dust allergy in Iran. Thirty-five samples of house dust collected from houses in the Caspian Sea region and five samples from other areas were examined for mites. The three pyroglyphid species Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei, reported by European and Japanses workers to be common in house dust and to be a major source of house dust allergens, were found to occur in Iranian house dust and to account for nearly two-thirds of the total mit population present in the dust. Dermatophagoidex pteronyssinus was the most frequent and most numerous species recorded, occurring in 90% of the samples examined and forming 94% of the pyroglyphid and 60% of the total mite population. The frequency with which house dust mites were found in the Iranian Caspian Sea region coupled with the relatively high frequency of allergic bronchial asthma in this area suggests that they may well be an important precipitating factor in asthma in Iran.

Skin tests were performed on 210 patients with house dust allergy and bronchial asthma or perennial rhinitis using extracts of Dermatophagoides pteronyssinus and of four storage mites most commonly found in house dust in the United Kingdom--Acarus siro, Tyrophagus putrescentiae, Lepidoglyphus (formerly Glycyphagus) destructor and Glycyphagus domesticus. The results of the skin tests were related to certain occupations and living conditions of the patients which could have exposed them to storage mites and some patients were included because their environment seemed especially likely to expose them to these species in order to assess the importance of these conditions. D. pteronyssinus was the most potent of the mite allergens and provoked the largest number of positive tests but a proportion of the storage mite species gave skin reactions which were larger or as large as those of D. pteronyssinus. No significant statistical correlation was found between reactions to D. pteronyssinus and any storage mite but highly significant correlations were found between some storage species. The frequency and strength of reactions to these species were unexpectedly high in view of their irregular occurrence and relative scarcity in house dust. It is suggested that sensitisation to these species occurs through exposure either to localised sources of infestation overlook during the random collection of floor or bedding dust or to infested materials encountered at work or other activities or to infested food or bedding of certain domestic pets. It is concluded that allergy to storage mites is more important and widespread that hitherto realised and is a considerable occupational hazard in farming communities and to those in occupations handling infested materials. Storage mites may also be important allergens for those living in very damp houses where the growth of moulds may encourage the development of Glycyphagus domesticus or other mites.

Oviposition and fecundity in the grain miteAcarus siro were studied at 5–30°C and 62.5–90% RH. At and above 20°C, 80% RH, mating and oviposition occurred soon after emergence, but at lower temperatures and humidities egg laying was progressively delayed from one to several days. Females needed to mate repeatedly in order to achieve maximum egg production, optimum conditions for which were 15°C, 90% RH, where total output per female averaged 435 with a maximum of 858. Oviposition rates were highest at higher temperatures, the mean daily rate at 20 and 25°C, 90% RH, rising to maximum levels of 28/29 eggs per female per day on day six.

Examination of dust from sleeping areas showed that storage mites, especially Glycyphagid species, were predominant in Brunei house dust. On skin testing sixty asthmatics with 1% extracts of six mite species, Dermatophagoides pteronyssinus was found to provoke the greatest number of positive skin reactions (66.7%), but positive reactions for Tyrophagus putrescentiae (50%), Acarus siro (35%), Glycyphagus domesticus (40%), and Lepidoglyphus destructor (45%) demonstrated that storage mites are also significant allergens. The role of storage mites in the causation of asthma in the tropics may have been underestimated.

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Summary The various species of mites in the bedding dust and in a number of quilts of twenty patients in Hong Kong with house-dust allergy have been identified and counted and skin tests performed with extracts of Dematophagoides spp. and six storage-mites. These results are compared with a similar study in London. The particular environmental conditions which influence the numbers of mites and exposure to them have also been studied. D. pteronyssinus is the most frequently occurring species in bedding dust in Hong Kong, as it is in London, and is found in higher numbers in the dust from quilts which appear to be the main source of allergy, as are pillows, blankets, eiderdowns and surface dust of mattresses in the U.K. All the patients of both groups gave positive skin-tests to this species. Temperature, humidity and rainfall are all at their highest during the summer in Hong Kong, the time when quilts are discarded and stored, usually several together, in cupboards or drawers providing optimal conditions for breeding of mites and spread of infestation. In a second group of eleven patients serial monthly D. pteronyssinus specific IgE-values, estimated by RAST, showed a peak in January approximately 2 months after increased exposure to the mites resulting from the quilts being put back onto the beds in October-November and an increase in the severity of patients' symptoms in November. There was a smaller peak in July possibly related to conditions caused by the high rainfall and cyclones in the preceding months. Storage mites were found in higher numbers in Hong Kong than in London house-dust probably because sleeping rooms were often used for eating and cooking. The predominant species was Blomia tropicalis which produced the highest number of positive skin tests of the six storage-species. These species have little allergenic relationship with Dermatophagoides so that hyposensitization with the latter may not be effective in patients with associated, predominantly storage-mite allergy.

VOORHORST et al.1 found that, among the many constituents of house dust causing allergic reactions of the respiratory tract (rhinitis and asthma) in people sensitive to house dust, a hitherto little known Pyroglyphid mite, Dermatophagoides pteronyssinus, contains allergens that are much more potent than those of other constituents. They also showed that excretory or secretory products of the mite contain the allergens. It therefore seemed probable that the mite could cause severe inhalation reactions should it become temporarily airborne and reach the upper or lower respiratory tract. Mechanical disturbance during bedmaking seemed a possible launching mechanism for making the mites airborne, especially because one of us (A. M. C.) found that D. pteronyssinus is very abundant in mattress dust.