Number of X-ray examinations performed on paediatric and geriatric patients compared with adult patients.

The age of the patient is of prime importance when assessing the radiological risk to patients due to medical X-ray exposures and the total detriment to the population due to radiodiagnostics. In order to take into account the age-specific radiosensitivity, three age groups are considered: children, adults and the elderly. In this work, the relative number of examinations carried out on paediatric and geriatric patients is established, compared with adult patients, for radiodiagnostics as a whole, for dental and medical radiology, for 8 radiological modalities as well as for 40 types of X-ray examinations. The relative numbers of X-ray examinations are determined based on the corresponding age distributions of patients and that of the general population. Two broad groups of X-ray examinations may be defined. Group A comprises conventional radiography, fluoroscopy and computed tomography; for this group a paediatric patient undergoes half the number of examinations as that of an adult, and a geriatric patient undergoes 2.5 times more. Group B comprises angiography and interventional procedures; for this group a paediatric patient undergoes a one-fourth of the number of examinations carried out on an adult, and a geriatric patient undergoes five times more.

Binge drinking in 19 year old men.

QUESTION UNDER STUDY: To describe alcohol use, binge drinking and drinking consequences in 19 year old men. METHODS: During a one-day army recruitment process mandatory for all Swiss males, a convenience sample of 1,004 men completed the "Health and Lifestyle Questionnaire", assessing demographics, alcohol use, binge drinking, and drinking consequences over the last 12 months. Binge drinking was defined as having 5 or more drinks on a single occasion at least once over the last 12 months. Among the 1,004 subjects, binge drinking could not be defined in 123 (12.3%) due to "don't know" responses, leaving 881 subjects with complete data. RESULTS: Of the 881 subjects, 690 (78.3%) reported binge drinking at least once over the last 12 months, 269 (30.5%) with infrequent binge drinking (< or = 1x/month) and 421 (47.8%) with frequent binge drinking (> or = 2x/month). In addition, 379 (43.0%) of the subjects experienced 3 or more drinking consequences over the last 12 months and the number of these consequences increased as the frequency of binge drinking increased (trend analyses significant for 9 of the 12 consequences evaluated). Among the 687 subjects with moderate average alcohol intake (< 14 drinks per week), 252 (36.7%) reported infrequent binge drinking, of whom 82 (32.5%) experienced 3 or more adverse drinking consequences over the last 12 months, whereas 246 (35.8%) reported frequent binge drinking and 128 (52.0%) of these experienced 3 or more adverse drinking consequences. CONCLUSIONS: Binge drinking in this sample of young men is frequent and is associated with numerous consequences, even among those consuming moderate amounts of alcohol.

Concurrent and simultaneous polydrug use among young Swiss males: use patterns and associations of number of substances used with health issues.

Background: Simultaneous polydrug use (SPU) may represent a greater incremental risk factor for human health than concurrent polydrug use (CPU). However, few studies have examined these patterns of use in relation to health issues, particularly with regard to the number of drugs used. Methods: In the present study, we have analyzed data from a representative sample of 5734 young Swiss males from the Cohort Study on Substance Use Risk Factors. Exposure to drugs (i.e., alcohol, tobacco, cannabis, and 15 other illicit drugs), as well as mental, social and physical factors, were studied through regression analysis. Results: We found that individuals engaging in CPU and SPU followed the known stages of drug use, involving initial experiences with licit drugs (e.g., alcohol and tobacco), followed by use of cannabis and then other illicit drugs. In this regard, two classes of illicit drugs were identified, including first uppers, hallucinogens and sniffed drugs; and then "harder" drugs (ketamine, heroin, and crystal meth), which were only consumed by polydrug users who were already taking numerous drugs. Moreover, we observed an association between the number of drugs used simultaneously and social issues (i.e., social consequences and aggressiveness). In fact, the more often the participants simultaneously used substances, the more likely they were to experience social problems. In contrast, we did not find any relationship between SPU and depression, anxiety, health consequences, or health. Conclusions: We identified some associations with SPU that were independent of CPU. Moreover, we found that the number of concurrently used drugs can be a strong factor associated with mental and physical health, although their simultaneous use may not significantly contribute to this association. Finally, the negative effects related to the use of one substance might be counteracted by the use of an additional substance.

Effects of environmental temperature on life tables of Rhodnius neivai Lent, 1953 (Hemiptera: Reduviidae) under experimental conditions

Changes in life tables of Rhodnius neivai due to variations of environmental temperature were studied, based on nine cohorts. Three cohorts were kept at 22°C, three at 27°C and three at 32°C. Cohorts were censused daily during nymphal instars and weekly in adults. Nine complete horizontal life tables were built. A high negative correlation between temperature and age at first laying was registered (r=-0,84). Age at maximum reproduction was significantly lower at 32°C. Average number of eggs/female/week and total eggs/female on its life time were significantly lower at 22°C. Total number of egg by cohort and total number of reproductive weeks were significantly higher at 27°C. At 32°C, generational time was significantly lower. At 27°C net reproductive rate and total reproductive value were significantly higher. At 22°C, intrinsic growth, finite growth and finite birth rates were significantly lower. At 22°C, death instantaneous rate was significantly higher.

Biology of Triatoma pallidipennis stal 1945 (Hemiptera: Reduviidae:Triatominae) under laboratory conditions

Aspects related to hatching, life time, mortality, feeding behaviour and fecundity for each stage of Triatoma pallidipennis life-cycle were evaluated. The hatching rate observed for 200 eggs was 60% and the average time of hatching was 18 days. Eighty nymphs (N) (40%) completed the cycle and the average time from NI to adult was 168.7±11.7days. The average span in days for each stage was 18.0 for NI, 18.5 for NII, 30.0 for NIII, 35.7 for NIV and 50.1 for NV. The number of bloodmeals at each nymphal stage varied from 1 to 5. The mortality rate was 9.17 for NI, 5.5 for NII, 6.8 for NIII 4.17 for NIV and 13.04 for NV nymphs. The average number of eggs laid per female in a 9-month period was 498.6. The survival rates of adults were 357±217.9 and 262.53±167.7 for males and females respectively.

A comparative study on the different staining methods and number of specimens for the detection of acid fast bacilli

The presence of acid fast bacilli in multiple specimens was investigated comparatively with Ziehl-Neelsen (ZN) and fluorescence microscopy (FM) staining in order to determine sensitivity in detecting tuberculosis (TB). A total of 465 specimens obtained from 295 patients were analysed at Harran University Medical School Hospital between March 1998 and March 2000. The culture was employed as the reference method. Sixty-eight patients (23.1%) were diagnosed as having TB by culture. The ZN and FM staining sensitivities were 67.6% (46/68) and 85.2% (58/68) respectively. Two hundred and one patients (68.1%) submitted one specimen to the laboratory. TB positivity was detected in 42 (20.9%) of these patients by culture. The sensitivities of ZN and FM stains were found to be 61% and 83% in these patients. However, in 18 patients (6.1%) who submitted two specimens to the laboratory, the TB was positive in six of them (33.3%) and ZN and FM sensitivities were 66% and 83% respectively. When three specimens or more were collected from the patients (76 patients, 25.8%), TB positivity was determined in 20 of them (26.3%) and the sensitivities were 80% and 92% in the ZN- and FM-stained smears, respectively. Our data indicate that in the diagnosis of TB, FM has greater sensitivity than ZN. In particular, in the case of a single specimen, the diagnostic value of FM is quite significant. It is, therefore, possible to conclude that both ZN and FM staining can be used for the diagnosis of TB when there are more than two specimens. However, if only one or two specimens are available, FM staining is preferable.

Impact of helpers on colony productivity in a primitively eusocial bee

Small societies of totipotent individuals are good systems in which to study the costs and benefits of group living that are central to the origin and maintenance of eusociality. For instance, in eusocial halictid bees, some females remain in their natal nest to help rear the next brood. Why do helpers stay in the nest? Do they really help, and if yes, is their contribution large enough to voluntarily forfeit direct reproduction? Here, we estimate the impact of helpers on colony survival and productivity in the sweat bee Halictus scabiosae. The number of helpers was positively associated with colony survival and productivity. Colonies from which we experimentally removed one helper produced significantly fewer offspring. However, the effect of helper removal was very small, on average. From the removal experiment, we estimated that one helper increased colony productivity by 0.72 additional offspring in colonies with one to three helpers, while the increase was smaller and not statistically significant in larger colonies. We conclude that helpers do actually help in this primitively eusocial bee, particularly in small colonies. However, the resulting increase in colony productivity is low, which suggests that helpers may be constrained in their role or may attempt to reproduce.

Determinants of high-growth firms:why do some countries have more high-growth firms than others?

High-growth firms have been shown to be a key factor for economic growth and structural change. This paper analyses the determinants of the number of high-growth firms in a country for 17 OECD countries between 1999 and 2005, using the Amadeus data set, the GEM data set, and others. The first contribution of this paper is that it is – as far as we know – the first empirical analysis of high-growth firms at the country level on the basis of actual measured growth. Second, we find indicative empirical evidence for three driving forces of high growth, viz. entrepreneurship, institutional settings, and opportunities for growth, all in accordance with theory and empirical findings in related fields of research. Third, the paper gives a tentative explanation of the differences in the average percentage of high-growth firms between countries. Finally, the paper gives some clues for policy makers how to promote high-growth firms. Keywords: high-growth firms, fast growing firms, entrepreneurship, institutional obstacles, opportunities for growth

Random mating with a finite number of matings.

Random mating is the null model central to population genetics. One assumption behind random mating is that individuals mate an infinite number of times. This is obviously unrealistic. Here we show that when each female mates a finite number of times, the effective size of the population is substantially decreased.

Using the Number of Pores on Fingerprint Images to Detect Spoofing Attacks

Abstract-Due to the growing use of biometric technologies inour modern society, spoofing attacks are becoming a seriousconcern. Many solutions have been proposed to detect the use offake "fingerprints" on an acquisition device. In this paper, wepropose to take advantage of intrinsic features of friction ridgeskin: pores. The aim of this study is to investigate the potential ofusing pores to detect spoofing attacks.Results show that the use of pores is a promising approach. Fourmajor observations were made: First, results confirmed that thereproduction of pores on fake "fingerprints" is possible. Second,the distribution of the total number of pores between fake andgenuine fingerprints cannot be discriminated. Third, thedifference in pore quantities between a query image and areference image (genuine or fake) can be used as a discriminatingfactor in a linear discriminant analysis. In our sample, theobserved error rates were as follows: 45.5% of false positive (thefake passed the test) and 3.8% of false negative (a genuine printhas been rejected). Finally, the performance is improved byusing the difference of pore quantity obtained between adistorted query fingerprint and a non-distorted referencefingerprint. By using this approach, the error rates improved to21.2% of false acceptation rate and 8.3% of false rejection rate.

Environmental characteristics of the cemeteries of Buenos Aires City (Argentina) and infestation levels of Aedes aegypti (Diptera: Culicidae)

Cemeteries with many water-filled containers, flowers, sources of human blood, and shade are favorable urban habitats for the proliferation of Aedes aegypti, a vector of yellow fever and dengue. A total of 22,956 containers was examined in the five cemeteries of the city of Buenos Aires, Argentina. The vector was found in four cemeteries that showed an average infestation level of 5.5% (617 positive out of 11,196 water-filled containers). The four cemeteries positive for Ae. aegypti showed significantly different (p<0.01) infestation levels. Vegetation cover and percentage of infestation were significantly correlated (p<0.01), but neither cemetery area nor number of available containers were significantly related to the proportion of positive vases. Our results suggest that the cemeteries of Buenos Aires represent a gradient of habitat favorableness for this vector species, some of which may act as foci for its proliferation and dispersal.

Isoenzyme profiles of Trypanosoma cruzi stocks from different areas of Paraguay

Twenty one Trypanosoma cruzi stocks from humans, domiciliary triatomines and one sylvatic animal of different areas of Paraguay were subjected to isoenzyme analysis. Thirteen enzyme systems (15 loci in total) were studied. MN cl2 (clonets 39) and SO34 cl4 (clonets 20) were used as references. Relationships between stocks were depicted by an UPGMA dendrogram constructed using the Jaccard´s distances matrix. Among the Paraguayan stocks 14 zymodemes were identified (Par1 to Par14), Par 5 being the most frequent. Polymorphism rate and clonal diversity were 0.73 and 0.93, respectively. Average number of alleles per polymorphic locus was 2.5 (range 2-4). These measurements show a high diversity, which is confirmed by the dendrogram topology. All stocks belong to the same lineage, as MN cl2 reference strain (T. cruzi II). Moreover three distinct subgroups were identified and two of them correspond to Brazilian and Bolivian zymodemes, respectively. The third subgroup, the most common in Paraguay, is related to Tulahuen stock. The large geographical distribution of some zymodemes agrees with the hypothesis of clonality for T. cruzi populations. However sample size was not adequate to detect genetic recombination in any single locality.

Seasonal analysis of the number of aeropiles in Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) from the State of Rio de Janeiro, Brazil

Variation between aeropile numbers of the right and left peritrematic plate in male and female Anocentor nitens (Neumann, 1897) is reported from a site in Brazil. From January to December 1998, 146 males and 247 females of A. nitens were recovered from Equus caballus L. in Silva Jardim District, State of Rio de Janeiro. Asymmetry of numbers of aeropiles between right and left plates occurred in 83.6% of the males and 82.2% of the females. Differences in the number of aeropiles between the sexes were not significant. Quantitative variation of aeropiles was correlated to the period of recovery, with significant asymmetry detected in August-September and November-December, mainly in males. Results suggest an adaptation, especially in the male ticks, that expresses itself as greater variation in the number of aeropiles in some periods of the year.