Mapping the birch and grass pollen seasons in the UK using satellite sensor time-series.

Grass and birch pollen are two major causes of seasonal allergic rhinitis (hay fever) in the UK and parts of Europe affecting around 15-20% of the population. Current prediction of these allergens in the UK is based on (i) measurements of pollen concentrations at a limited number of monitoring stations across the country and (ii) general information about the phenological status of the vegetation. Thus, the current prediction methodology provides information at a coarse spatial resolution only. Most station-based approaches take into account only local observations of flowering, while only a small number of approaches take into account remote observations of land surface phenology. The systematic gathering of detailed information about vegetation status nationwide would therefore be of great potential utility. In particular, there exists an opportunity to use remote sensing to estimate phenological variables that are related to the flowering phenophase and, thus, pollen release. In turn, these estimates can be used to predict pollen release at a fine spatial resolution. In this study, time-series of MERIS Terrestrial Chlorophyll Index (MTCI) data were used to predict two key phenological variables: the start of season and peak of season. A technique was then developed to estimate the flowering phenophase of birch and grass from the MTCI time-series. For birch, the timing of flowering was defined as the time after the start of the growing season when the MTCI value reached 25% of the maximum. Similarly, for grass this was defined as the time when the MTCI value reached 75% of the maximum. The predicted pollen release dates were validated with data from nine pollen monitoring stations in the UK. For both birch and grass, we obtained large positive correlations between the MTCI-derived start of pollen season and the start of the pollen season defined using station data, with a slightly larger correlation observed for birch than for grass. The technique was applied to produce detailed maps for the flowering of birch and grass across the UK for each of the years from 2003 to 2010. The results demonstrate that the remote sensing-based maps of onset flowering of birch and grass for the UK together with the pollen forecast from the Meteorology Office and National Pollen and Aerobiology Research Unit (NPARU) can potentially provide more accurate information to pollen allergy sufferers in the UK.

Exploring the spatio-temporal relationship between two key aeroallergens and meteorological variables in the United Kingdom.

Constructing accurate predictive models for grass and birch pollen in the air, the two most important aeroallergens, for areas with variable climate conditions such as the United Kingdom, require better understanding of the relationships between pollen count in the air and meteorological variables. Variations in daily birch and grass pollen counts and their relationship with daily meteorological variables were investigated for nine pollen monitoring sites for the period 2000-2010 in the United Kingdom. An active pollen count sampling method was employed at each of the monitoring stations to sample pollen from the atmosphere. The mechanism of this method is based on the volumetric spore traps of Hirst design (Hirst in Ann Appl Biol 39(2):257-265, 1952). The pollen season (start date, finish date) for grass and birch were determined using a first derivative method. Meteorological variables such as daily rainfall; maximum, minimum and average temperatures; cumulative sum of Sunshine duration; wind speed; and relative humidity were related to the grass and birch pollen counts for the pre-peak, post peak and the entire pollen season. The meteorological variables were correlated with the pollen count data for the following temporal supports: same-day, 1-day prior, 1-day mean prior, 3-day mean prior, 7-day mean prior. The direction of influence (positive/negative) of meteorological variables on pollen count varied for birch and grass, and also varied when the pollen season was treated as a whole season, or was segmented into the pre-peak and post-peak seasons. Maximum temperature, sunshine duration and rainfall were the most important variables influencing the count of grass pollen in the atmosphere. Both maximum temperature (pre-peak) and sunshine produced a strong positive correlation, and rain produced a strong negative correlation with grass pollen count in the air. Similarly, average temperature, wind speed and rainfall were the most important variables influencing the count of birch pollen in the air. Both wind speed and rain produced a negative correlation with birch pollen count in the air and average temperature produced a positive correlation.

Evaluation of a fast, objective tool for assessing body condition of budgerigars (Melopsittacus undulatus).

There is currently no suitable system available for the assessment of budgerigar body condition. A tool has been developed that uses an algorithmic decision tree of yes-no answers based on physical examination to objectively guide the assessor to a body condition score. The aim of this work was to evaluate the guide. Repeatability and reproducibility were measured by four assessors on three sequential days, using 38 budgerigars of mixed sex, age and weight. Data were analysed using a 3-factor anova, with Person and Bird as variable factors and occasion as a fixed factor. The association between body condition score and body fat was measured using three assessors and 63 dead budgerigars, which were chemically analysed for fat content after assessment. Data were statistically analysed to determine correlation using Spearman's Rank Coefficient. Occasion and person had no significant effect on body condition score (p = 0.988 and 0.347 respectively). Body condition score and percentage body fat were highly significantly correlated (R(2) = 0.768): percentage fat increased with increasing body condition score. The guide would appear to be a repeatable measure of body condition in budgerigars, suitable for use during physical examinations.

Pollen season and climate: is the timing of birch pollen release in the UK approaching its limit?

In light of heightened interest in the response of pollen phenology to temperature, we investigated recent changes to the onset of Betula (birch) pollen seasons in central and southern England, including a test of predicted advancement of the Betula pollen season for London. We calculated onset of birch pollen seasons using daily airborne pollen data obtained at London, Plymouth and Worcester, determined trends in the start of the pollen season and compared timing of the birch pollen season with observed temperature patterns for the period 1995-2010. We found no overall change in the onset of birch pollen in the study period although there was evidence that the response to temperature was nonlinear and that a lower asymptotic start of the pollen season may exist. The start of the birch pollen season was strongly correlated with March mean temperature. These results reinforce previous findings showing that the timing of the birch pollen season in the UK is particularly sensitive to spring temperatures. The climate relationship shown here persists over both longer decadal-scale trends and shorter, seasonal trends as well as during periods of 'sign-switching' when cooler spring temperatures result in later start dates. These attributes, combined with the wide geographical coverage of airborne pollen monitoring sites, some with records extending back several decades, provide a powerful tool for the detection of climate change impacts, although local site factors and the requirement for winter chilling may be confounding factors.

Microbiological diagnosis of prosthetic joint infections: a prospective evaluation of four bacterial culture media in the routine laboratory.

The diagnosis of prosthetic joint infection (PJI) in the routine microbiology laboratory is labour-intensive, but semi-automated methods may be appropriate. We prospectively compared four microbiological culture methods on samples taken at prosthetic joint revision surgery. Automated BACTEC blood culture bottles and cooked meat enrichment broth were the most sensitive methods (87% and 83%, respectively, as compared with fastidious anaerobic broth (57%) and direct plates (39%)); all were highly specific (97-100%). To our knowledge, this is the first prospective study aimed at comparing culture methods in routine use in UK clinical laboratories for the diagnosis of PJI.

Pre-focused lead titanate > 25 MHz single-element transducers from hollow spheres.

Miniature lead titanate (PT) hollow spheres with diameters in the 1 to 10 mm range and wall thicknesses of 20 to 120 microns have been fabricated. Shell sections were used as components of pre-focused transducers. Spheres are produced using a new sacrificial core technique that produces hundreds of spheres with a more uniform wall thickness than those produced by earlier methods. Shells produced from these spheres were found to have a wall thickness variation of about 10%. Despite this variation, bulk properties were estimated from capacitance and impedance data. Shells tested in this work had dielectric constants (1 kHz) near 280 with loss factor of < 2% and d33 values of 68 pC/N. Thickness coupling coefficients averaged 0.51 with mechanical quality factors of < 15. A transducer fabricated from these sections of spheres had a round-trip insertion loss of -20.1 dB at the center frequency of 39.8 MHz and a 6 dB bandwidth of 33%.

Modeling and underwater characterization of cymbal transducers and arrays.

The cymbal is a miniaturized class V flextensional transducer that was developed for potential use as a shallow water sound projector and receiver. Single elements are characterized by high Q, low efficiency, and medium power output capability. Its low cost and thin profile allow the transducer to be assembled into large flexible arrays. Efforts were made to model both single element and transducer arrays by coupling finite element analysis (ATILA) and the integral equation formulation (EQI). The pressure and velocity distributions on the surface elements were calculated by ATILA and later used with EQI to calculate the far field properties of the transducer element and arrays. It eliminates the mesh of the fluid domain and makes the 3-D model of a transducer possible. Three-dimensional models of a cymbal transducer and a 3 x 3 cymbal array were developed in the modeling. Very good agreement was obtained between modeling and measurement for single element transducers. By coupling finite element analysis with the integral equation method using boundary elements, acoustic interaction effects were taken into account. Reasonable agreement was obtained between calculation and measurement for a 3 x 3 array.

A miniature class V flextensional cymbal transducer with directional beam patterns: the double-driver.

The "double-driver" cymbal, a directional class V flextensional transducer, is described in this paper. Its basic structure is a bilaminar piezoelectric disk with metal caps as mechanical transformers and amplifiers. The directivity was accomplished by exciting the double-driver in a combined flexural and bending mode causing the sound pressure to add in one direction and cancel in the opposite direction. The cardioid beam pattern predicted by finite element modeling agreed well with the experimental measurements. A 3 x 3 double-driver array was constructed to demonstrate that under optimal conditions the array can provide a directional beam pattern with a front-to-back ratio of more than 20 dB.

Cymbal array: a broad band sound projector.

A prototype 3 x 3 planar cymbal transducer array was built and tested. The array has a radiating area of 5.5 cm x 5.5 cm and a thickness of less than 8 mm. The measured transmitting voltage response was above 134 dB re 1 microPa/V @ 1 m and flat over the frequency range of 16 and 100 kHz. Array interaction was analyzed using an equivalent circuit model. The array interaction leads to variations in radiation resistance and velocity of the transducers in the array according to their surroundings in the array. The effect is enhanced overall efficiency and a flat response.

Invasive pneumococcal disease in a cohort of predominantly HIV-1 infected female sex-workers in Nairobi, Kenya.

BACKGROUND: HIV infection is a major risk factor for pneumococcal disease in industrialised countries. Although both are common infections in sub-Saharan Africa, few studies have investigated the importance of this interaction. We have followed up a cohort of female sex-workers in Nairobi and report here on the extent of invasive pneumococcal disease. METHODS: A well-established cohort of low-class female sex-workers, based around a community clinic, was followed up from October, 1989, to September, 1992. 587 participants were HIV positive and 132 remained HIV negative. Set protocols were used to investigate common presentations. Cases were identified clinically and radiographically. Streptococcus pneumoniae and other pathogens were diagnosed by culture. FINDINGS: Seventy-nine episodes of invasive pneumococcal disease were seen in the 587 HIV-positive women compared with one episode in the 132 seronegative women (relative risk 17.8, 95% CI 2.5 to 126.5). In seropositive women the incidence rate was 42.5 per 1000 person-years and the recurrence rate was 264 per 1000 person-years. By serotyping, most recurrent events were re-infection. A wide spectrum of HIV-related pneumococcal disease was seen: only 56% of cases were pneumonia; sinusitis was seen in 30% of cases, and occult bacteraemia, a novel adult presentation, in 11%. Despite forty-two bacteraemic episodes, no deaths were attributable to Strep pneumoniae. At first presentation the mean CD4 cell count was 302/microL(SD 191) and was 171/microL (105) for recurrent episodes. During acute Strep pneumoniae infection the CD4 cell count was reversibly suppressed (mean fall in sixteen episodes, 105/microL [123]). The neutrophil response to acute infection was blunted and was correlated with CD4 count (r=0.50, 95% CI 0.29 to 0.66). Strep pneumoniae caused more disease, at an earlier stage of HIV immunosuppression, than Mycobacterium tuberculosis or non-typhi salmonellae. INTERPRETATION: Our study highlights the importance of the pneumococcus as an early but readily treatable complication of HIV infection in sub-Saharan Africa.

Essentiality of boron for healthy bones and joints.

Since 1963, evidence has accumulated that suggests boron is a safe and effective treatment for some forms of arthritis. The initial evidence was that boron supplementation alleviated arthritic pain and discomfort of the author. This was followed by findings from numerous other observations epidemiologic and controlled animal and human experiments. These findings included a) analytical evidence of lower boron concentrations in femur heads, bones, and synovial fluid from people with arthritis than from those without this disorder; b) observation evidence that bones of patients using boron supplements are much harder to cut than those of patients not using supplements; c) epidemiologic evidence that in areas of the world where boron intakes usually are 1.0 mg or less/day the estimated incidence of arthritis ranges from 20 to 70%, whereas in areas of the world where boron intakes are usually 3 to 10 mg, the estimated incidence of arthritis ranges from 0 to 10%; d) experimental evidence that rats with induced arthritis benefit from orally or intraperitoneally administered boron; e) experimental evidence from a double-blind placebo-boron supplementation trial with 20 subjects with osteoarthritis. A significant favorable response to a 6 mg boron/day supplement was obtained; 50% of subjects receiving the supplement improved compared to only 10% receiving the placebo. The preceding data indicate that boron is an essential nutrient for healthy bones and joints, and that further research into the use of boron for the treatment or prevention of arthritis is warranted.

Infection and morbidity in patients with tuberculosis in Nairobi, Kenya.

OBJECTIVE: To examine the role of acute infection as a cause of morbidity in patients with tuberculosis. DESIGN: Cross-sectional documentation of predefined acute morbid events. SETTING: Infectious Diseases Hospital, Nairobi, Kenya. PATIENTS: Adults (> or = 15 years), inpatients and outpatients with a diagnosis of tuberculosis presenting with one or more of a series of clinical features. A new event was defined as one occurring at least 1 week after the initial event. INTERVENTIONS: Patients' treatment was modified depending on the results of laboratory investigations. MAIN OUTCOME MEASURES: There were 642 events from 398 patients, 235 HIV-positive patients had 438 events and 163 HIV-negative patients had 204 events (P < 0.0001). Forty-two out of the 235 (18%) HIV-positive patients were bacteraemic compared with nine out of the 163 (6%) HIV-negative patients (P = 0.0003). The most common isolates from blood were Salmonella typhimurium and Streptococcus pneumoniae. RESULTS: Faecal specimens were obtained more commonly from HIV-positive patients (P < 0.001), and often contained bacterial pathogens. CONCLUSIONS: Many of the causes of morbidity in patients with tuberculosis and HIV are not due to tuberculosis or antituberculous therapy, and will not be identified without microbiological investigation.

PIP: Tuberculosis (TB) is a common complication of HIV in Africa. A 1988-89 study further confirmed that considerable morbidity and mortality from acute bacterial infection occurred in HIV patients. It has also been found that anti-TB therapy seems to be as effective in HIV-positive as in HIV-negative TB patients. This paper reports on the level and nature of infectious morbidity suffered by HIV-positive patients receiving treatment for TB. The assessment is based upon a sample of inpatients and outpatients at the Infectious Diseases Hospital in Nairobi. Patients were aged 15 years and older, with a TB diagnosis presenting with 1 or more of a series of clinical features. 642 morbid events were seen in 398 patients: 235 HIV-positive patients had 438 event and 163 HIV-negative patients had 204 events. 18% of the HIV-positive patients versus 6% of the HIV-negative patients were bacteremic. Salmonella typhimurium and Streptococcus pneumoniae were most commonly isolated from sera, while fecal specimens were obtained more commonly from HIV-positive patients and often contained bacterial pathogens. The authors conclude that many causes of morbidity in patients with TB and HIV are not due to TB or anti-TB therapy and will not be identified without microbiological investigation. These results suggest that even with effective anti-TB chemotherapy HIV-positive patients will remain or become unwell.

Cohort study of human immunodeficiency virus infection in patients with tuberculosis in Nairobi, Kenya. Analysis of early (6-month) mortality.

Retrospective studies suggest that the mortality rate from HIV-1-associated tuberculosis is greater than that from tuberculosis alone, but it is not clear if this is due to failure of antituberculosis treatment or to the complications of HIV-1 infection. We have carried out a prospective cohort study of patients with tuberculosis in Nairobi, Kenya, to compare mortality rates, risk factors, and causes of death in HIV-1 positive and HIV-1 negative patients. One hundred seven HIV-1 positive and 174 HIV-1 negative patients with tuberculosis attending two tuberculosis treatment centers in Nairobi were enrolled and followed monthly. Mortality was significantly higher in HIV-1 positive than in HIV-1 negative patients within 6 months of the start of antituberculosis treatment after adjustment for age, sex, and education (rate ratio = 3.8; 95% confidence interval, 1.7 to 8.1; p less than 0.001). Most of the excess mortality occurred after the first month of treatment and was due to nontuberculous infections. Predictors for mortality differed greatly between HIV-1 positive and HIV-1 negative patients. Mortality was greater in HIV-1 positive patients treated with a "standard" regimen for tuberculosis than in HIV-1 positive patients receiving a "short-course" regimen (p = 0.08 when adjusted for all independent risk factors). Tuberculosis control programs in developing countries need to implement "short-course" regimens and train health workers to recognize and treat nontuberculous infections to maintain their effectiveness in the face of the HIV epidemic.

The presentation and outcome of HIV-related disease in Nairobi.

The range of clinical presentations of HIV-related disease in Africa has not been adequately described, despite the fact that many hospitals have to rely heavily on clinical diagnosis. Six hundred adult medical patients seen in the Casualty Department of the main Government hospital in Nairobi were enrolled in a study of the presentation and outcome of HIV-related disease: 506 of these patients were admitted, of whom 19 per cent (95) were HIV seropositive. The remaining 94 were dealt with as outpatients: 11 percent (10) of these were seropositive. A history of prior treatment for sexually transmitted disease and, if male, being uncircumcised, were associated with being seropositive. Three presentations were strongly associated with HIV infection: acute fever with no focus except the gastrointestinal tract (enteric fever-like illness), acute cough with fever (community-acquired pneumonia) and chronic diarrhoea with wasting. The WHO clinical case definition (CCD) for AIDS missed a substantial amount of HIV-related morbidity (sensitivity 39 per cent) and misidentified many seronegative patients (positive predictive value 59 per cent). In comparison with the Centers for Disease Control surveillance definition for AIDS, the CCD was specific (91 per cent) and sensitive (79 per cent) but only had a positive predictive values of 30 per cent: the CCD may therefore be a poor surveillance tool for AIDS. Seropositive patients were much more likely to die than were seronegative patients (39 per cent vs. 15 per cent mortality). Enteric fever-like illness was the presentation which most commonly proved fatal. A wider spectrum of disease is associated with underlying HIV immunosuppression than has previously been described in Africa.

Piezoelectric composites with high sensitivity and high capacitance for use at high pressures.

A type of piezoelectric composite has been developed for oceanographic applications. The composites have a large figure of merit (d(h)xg(h) or d(h )xg(h)/tan delta, where d(h ) is the hydrostatic piezoelectric voltage coefficient), a large dielectric constant (K) and low dielectric loss, and great mechanical strength. A shallow cavity between the PZT ceramics and thick metallic electrode is designed to convert a portion of the z-direction stress into a large radial and tangential stress of opposite sign. thereby causing the d(33) and d(31) contributions to d(h) to add rather than subtract, and raising the figure of merit. Theoretical stress analysis was carried out using an axisymmetric finite element method. Experimental results show that the d(h)x g(h), K, and withstandable pressure are extremely high.

Agricultural practices affect arthritis.

It has been suggested that boron deficiency in food may be a cause of some arthritis (Newnham 1979). Epidemiological studies were done to try to ascertain why some countries have more or less arthritis than other countries. Jamaica, Mauritius, Fiji and Israel were visited with a view to ascertaining the boron levels of locally consumed food as it was suspected that excessive use of soluble chemical fertilizers had damaged the soils of the sugar producing lands. Food grown on these soils were found to have low boron levels. By contrast the foods consumed in Israel had high boron concentrations associated with a low incidence of arthritis. South African work has shown that people who eat mostly maize have more arthritis when eating processed maize grown with fertilizer. Brief reference is made to the role of boron in human diets. There are bound to be geographical differences in dietary boron, but even in the USA levels have dropped considerably in 50 years. Arthritis is increasing, especially juvenile arthritis. The increased use of fertilizers and genetic selection of plants has led to a wide range of changes in the quality of foodstuffs and their nutrient content. The identification of the parallel loss of boron may reflect vital changes in trace elements and other nutrients.

Extrapulmonary and disseminated tuberculosis in HIV-1-seropositive patients presenting to the acute medical services in Nairobi.

We studied 506 consecutive adult acute medical admissions to hospital in Nairobi; 95 (18.8%) were seropositive for HIV-1, and 43 new cases of active tuberculosis (TB) were identified. TB was clearly associated with HIV infection, occurring in 17.9% of seropositive patients compared with 6.3% of seronegatives [odds ratio (OR) 3.2; 95% confidence limits (CL) 1.6-6.5]. Extrapulmonary disease was more common in seropositive than seronegative TB patients (nine out of 17 versus five out of 26; OR 4.7; 95% CL 1.01-23.6); this accounted for most of the excess cases of TB seen in seropositive patients. Mycobacteraemia was demonstrated in two of eight seropositive TB patients but in none of 11 seronegative TB patients. No atypical mycobacteria were isolated. The World Health Organization (WHO) clinical case definition for African AIDS did not discriminate well between seropositive and seronegative TB cases. Five out of seven seropositive women with active tuberculosis had delivered children in the preceding 6 months and were lactating, compared with only one out of eight seronegative tuberculous women. An association between recent childbirth, HIV immunosuppression and the development of TB is suggested.

Life-threatening bacteraemia in HIV-1 seropositive adults admitted to hospital in Nairobi, Kenya.

During 6 months, 506 consecutive adult emergency admissions to hospital in Nairobi were enrolled in a study of bacteraemia and HIV infection. 19% were HIV-1 antibody positive. Significantly more HIV-seropositive than seronegative patients had bacteraemia (26% vs 6%). The predominant organisms isolated from the seropositive patients were Salmonella typhimurium and Streptococcus pneumoniae. Mortality was higher in the seropositive than in the seronegative bacteraemic patients. The findings suggest that non-opportunistic bacteria are important causes of morbidity and mortality in HIV-infected individuals in Africa.

Acoustic properties of particle/polymer composites for ultrasonic transducer backing applications.

The acoustic impedance and attenuation in composites made of particle fillers loaded in polymer matrices for transducer backing applications is investigated. The acoustic impedance of tungsten/vinyl composites was modeled, and an experimental matrix identifying variables that contribute to composite attenuation was established. The variable included the particle type, the particle size and volume fraction of a filler, the physical characteristics of the polymer matrix, and the processing route that determined the composite connectivity. Experimental results showed that with an increase in filler particle size or a decrease in volume fraction of filler, there is an increase in composite attenuation. Overall, the various types of filler, the polymer matrix, and the interface between the two contribute to attenuation in the composite, as confirmed by the acoustic properties and the microstructural analysis.