Forest ecology. Satellites spy more forest than expected.
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We report the development of a prototype database that "maps" microbial diversity in the context of the geochemical and geological environment and geographic location. When it is fully implemented, scientists will be able to conduct database searches, construct maps containing the information of interest, download files, and enter data over the Internet.
Apoptotic regulation of monocytes/macrophages appears to be closely associated with chronic inflammatory reactions. Since it was demonstrated earlier that certain bacterial cell components are involved in apoptotic regulation of these cells, in the present study, we investigated whether the bacterial fimbria, an important cell structure involved in bacterial adherence to host cells, regulates apoptosis of human monocytic THP-1 cells induced under growth factor deprivation. To investigate this point, we used fimbriae of Porphyromonas gingivalis, a pathogen causing periodontal disease, which is a chronic inflammatory disease. The fimbriae inhibited apoptosis of the cells under growth factor deprivation. This inhibitory action of the fimbriae was completely neutralized by anti-fimbrial antibody. The fimbriae stimulated activation of extracellular signal-regulated kinase (ERK) and expression of cyclin-dependent kinase inhibitor p21 Cip/WAF1 (p21) in the cells. The stimulatory effect of the fimbriae on the expression of the p21 protein was inhibited by treatment with PD98059, a specific inhibitor of ERK. The cell apoptosis was inhibited by treatment with Ac-DEVD-CHO, an inhibitor of caspase-3. The fimbriae inhibited the serum withdrawal-induced cleavage of the caspase-3 proform and poly(ADP-ribose) polymerase, one of the caspase-3 substrates. Furthermore, PD98059 and antisense p21 oligonucleotide blocked the fimbrial inhibition of apoptosis and caspase-3 activation of the cells induced by serum withdrawal. These results show that the bacterial fimbriae inhibited apoptosis of THP-1 cells induced under growth factor deprivation via ERK-dependent expression of p21. The present study suggests that bacterial fimbriae act as potent regulators of chronic inflammatory disease, e.g., periodontal disease, through blocking apoptosis of monocytes/macrophages.
The prevalence and distribution of trachoma in the Sudan has been studied. The morbidity rate of 83.2 per 1000 in the Northern Province decreases southwards until it reaches 0.94 in the extreme south (Equatoria Province). 2. In endemic areas infection starts very early--in the first year of life. 3. There is a marked difference between the prevalence of trachoma in towns and villages--71.3 per cent for the age group 1-4 years in villages, and 56.7 per cent for the same age group in the towns. This is probably due to better standards of living and hygiene in the towns. 4. Some relationship has been found between the rainfall, the relative humidity, and the incidence of trachoma, but this does not necessarily apply in other countries. 5. The factors that may explain the high prevalence of trachoma in the northern Sudan are: a. Mechanical trauma caused by frequent sandstorms. b. Irritation of the eyes by dust particles, leading to excessive watering and discharge, and rubbing with the fingers. c. The habit of frequent hand-shaking. d. Poor personal hygiene in pre-schoolchildren. e. Associated bacterial conjunctivitis. f. The presence of eye-seeking flies.
A method of dividing a map of the practice area into a grid based on postcode locations is described. The distribution of the practice population may thus be shown graphically and trends observed. The geographical incidence and prevalence of morbidity may also be charted and variations of statistical significance determined. This is a practical tool that will have greater potential as information technology in general practice develops.
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OBJECTIVE: To identify where in England there are likely to be most constraints on choice of hospital for patients waiting longer than six months for elective care. DESIGN: Cross sectional study using routinely collected data. SETTING: Population of England and NHS trusts and private sector hospitals in England. PARTICIPANTS: All residents in England. MAIN OUTCOME MEASURES: Availability of beds (available and unoccupied hospital beds), demand (number of people waiting longer than six months), and access (travel time to facilities) to hospital care in England. RESULTS: Most people in England already have an extensive potential choice of hospital. The number of available and unoccupied beds within 60 minutes' travel time was lowest in the Scottish borders, North Yorkshire, and parts of East Anglia, Lincolnshire, Devon, and Cornwall. This pattern was not altered by adding in private facilities. Putting demand with this supply, the number of people in a geographical area waiting longer than six months per bed within 60 minutes' travel time was highest in the south east (except London), parts of the south west (Cornwall, Bristol), East Anglia, and the Welsh border. CONCLUSION: People in the south east (outside London), East Anglia, and parts of the south west are likely to have to travel further to exercise meaningful choice of hospital for elective care.
Data relating to the incidence of anencephalus for the 12-year period 1961-72 were abstracted from the Statistical Reviews of the Registrar General for Scotland. It was shown that considerable geographical variation is still apparent with the highlands having, in general, the lower incidences. In comparison with the earlier study of Edwards (1958), there were some changes: the incidence in the areas to the west had increased and that in those to the east decreased. During the 12-year period there was an overall decline in the incidence of the lesion; this was most marked in births to women under 20 years, and to those of social classes III, IV, and V. The decline was least apparent for births to women of high social class and the unmarried. It was shown that there was little seasonal variation in the time of delivery, but that even when the trend had been taken into account the yearly fluctuation was significantly different from that expected, with an excess of cases in 1961 and 1971.
This paper presents an approach to the well-known Travelling Salesman Problem (TSP) using Self-Organizing Maps (SOM). The SOM algorithm has interesting topological information about its neurons configuration on cartesian space, which can be used to solve optimization problems. Aspects of initialization, parameters adaptation, and complexity analysis of the proposed SOM based algorithm are discussed. The results show an average deviation of 3.7% from the optimal tour length for a set of 12 TSP instances.
In this paper we proposed an unsupervised neural architecture, called Temporal Parametrized Self Organizing Map (TEPSOM), capable of learning and reproducing complex robot trajectories and interpolating new states between the learned ones. The TEPSOM combines the Self-Organizing NARX (SONARX) network, responsible for coding the temporal associations of the robotic trajectory, with the Parametrized Self-Organizing (PSOM) network, responsible for an efficient interpolation mechanism acting on the SONARX neurons. The TEPSOM network is used to model the inverse kinematics of the PUMA 560 robot during the execution of trajectories with repeated states. Simulation results show that the TEPSOM is more accurate than the SONARX in the reproduction of the learned trajectories.
In this paper, a network of coupled chaotic maps for multi-scale image segmentation is proposed. Time evolutions of chaotic maps that correspond to a pixel cluster are synchronized with one another, while this synchronized evolution is desynchronized with respect to time evolution of chaotic maps corresponding to other pixel clusters in the same image. The number of pixel clusters is previously unknown and the adaptive pixel moving technique introduced in the model makes it robust enough to classify ambiguous pixels.
In this paper, we present a two-layer self-organizing neural network based method for handwritten digit recognition. The network consists of a base layer self-organizing map and a set of corresponding maps in the second layer. The input patterns are partitioned into subspace in the first layer. Patterns in a subspace are led to the second layer and a corresponding map is built according to the first layer performance. In the classification process, each pattern searches for several closest nodes from the base map and then it is classified into a specified class by determining the nearest model of the corresponding maps in the second layer. The new method yielded higher accuracy and faster performance than the ordinary self-organizing neural network.
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