Patterns of care of radiotherapy in México

Aim

This survey is performed to learn about the structure of radiotherapy in México.

Background

Radiation oncology practice is increasing because of the higher incidence of cancer. There is no published data about radiotherapy in México.

Materials and methods

A questionnaire was sent to the 83 registered centers in the database of the Mexican regulatory agency. One out of the 32 states has no radiotherapy. 27 centers from 14 states provided their answers.

Results

829 patients are treated annually with any radiotherapy modality in each center. Two centers have one cobalt machine, 7 have a cobalt and a linac and 10 have more than one linac. Five centers use 2D planning systems, 22 use 3D; 9, conventional simulators; 22, CT based simulation, and 1 center has no simulation. Most of the centers verify beams with films, electronic portal image devices and cone beam CTs are also used. Intensity modulated and image guided radiotherapy are performed in 5 states. Breast, prostate, cervix, lung, rectum and head and neck cancer are the six most common locations. There are 45 public and 38 private centers, 2 dedicated to children. Two gamma knife units, 5 Novalis systems, 1 tomotherapy and 2 cyberknife machines are working. All centers have at least one radiation oncologist, one physicist and one radiotherapist.

Conclusions

Definitive conclusions cannot be drawn from this limited feedback due to a low participation of centers. This survey about radiotherapy in Mexico shows the heterogeneity of equipment as well as medical and technical staff in the whole country.     

Satellite tracking of Adélie penguins

Summary Female Adélie penguins (Pygoscelis adeliae) that take too long on their first post-laying foraging trip are a major cause of breeding failure, but in the ice-filled waters of Antarctica, determining where they go and why they are away so long has proved difficult. Here we describe the first successful attempt to track penguins at sea using satellite telemetry. Four females foraged in different locations, dispelling the notion of a common feeding ground. They moved up to 272 km from the rookery and covered from 551 to 1,121 km on their trips, swimming at minimum average speeds around 1.2 m/s. The birds were most likely to be in the water between 0630 and 1430 when light intensity, important for a visual predator, was greatest. Carrying the transmitters reduced rates of fat deposition (weight gain), increasing the duration of foraging trips of females, and suggested that they may forage until their fat depots reach a minimum threshold level. This has two implications: (i) durations of these postlaying foraging trips could potentially be used as an indicator of krill abundance (Euphausia sp), the almost exclusive food of Adélie penguins during this period, and (ii) any reduction in krill stocks caused by harvesting could increase foraging trip durations with a concomitant increase mi breeding failures.     

Studies on the Fluorescence of Saké

By spectrofluorophotometric investigation on various kinds of Saké it was found that they have at least two kinds of fluorescent colors, the one is blue, the other yellowish green. The former is always more dominant than the latter, but is unstable although the intensities of both color decrease remarkably by treatment of active charcoal. Ferulic acid and harman as the blue fluorescent components are isolated, the former from Saké in young, the latter from Saké kept for a long time under direct sun light.     

Photosynthesis of plant régénérants. Specificity ofin vitro conditions and plantlet response

Regenerants from tobacco(Nicotiana tabacum L. cv. White Burley) leaf segments cultivatedin vitro in vessels with solid agar medium under usual conditions (plantlets) grew under very low irradiance (I = 40 μxmol m?2 s?1), very high relative humidity (more than 90%) and decreased CO₂ concentration (c_a) during light period. In comparison with seedlings of a similar number of leaves and similar total leaf area grown in sand and nutrient solution, the plantlets had lower dry mass of shoots and roots per plant and thinner leaves almost without trichomes and epicuticular waxes. Due to a low transpiration rate under high relative humidity the water potential of plantlet leaves was higher than that of seedling leaves and the difference in water potential between leaves and medium was lowei. The rate of water loss from leaves detached from plantlets was considerably faster than that from seedlings under the same conditions (I = 110 μrnol m^?2; s^?1, temperature 30 °C, relative humidity 50 %). Net photosynthetie rates (P_n) of leaves of plantlets and seedlings measured under saturating I, natural ca and the leaf temperature 20 °C were similar, nevertheless the shape of curves relating Pn to c» indicated some differences in photosynthetie parameters(e.g. saturation of Pn under lower ca> higher CO2 compensation concentration in plantlets than in seedlings). Similarly compensation and saturating I were lower in plantlets than in seedlings. The shape of transpiration curves as well as the expressive linear phases of P_N(ca) and P_N(I) curves of plantlet leaves indicated ineffective stomatal control of gas exchance. These results were confirmed by microscopic observations of stomatal movementsin situ     

Spatial and seasonal distribution of the ichthyofauna of Lake Nokoué, Bénin,west Africa

The fish biodiversity of Lake Nokoué, a lagoon in Bénin, was monitored for one year from August 2000 to July 2001 by means of samples from the artisanal fishery collected once a month at three stations. A total of 5 933 fish weighing 95 322g (mean individual weight 16.0g) belonging to 51 species, 47 genera and 34 families were sampled. An abundance of juveniles was observed, confirming the importance of the lake as nursery grounds, rich in exploitable habitats like other tropical estuaries and lagoons. The fish fauna comprised three main components: i) an estuarine component (strict, freshwater and marine origins) which is the basis of the lagoon fauna community and which is stable in space and time; ii) a marine component containing fishes which appeared in the lagoon during the dry season where the salinity remains high (>20‰) and iii) a freshwater component with fishes coming into the lagoon from the river during the flood period. The magnitude of the spatial and seasonal fluctuations of the last two components varies depending on the area: marine (Zogbo), freshwater (Vêki) or intermediate (Ganvié). The global species richness and the relative abundances of fish vary between stations and from month to month. November, with 20 species on average, and January, with 6 species on average, are significantly different as regards species richness.     

The longue durée of contraceptive methods

Medical history has so far paid hardly any attention to the longue durée, a history in which, according to Braudel, 'all change is slow'. It is therefore one of the challenges of the emerging field of the social history of medicine to work audaciously across time as well as across space. An interesting subject, for example, is the history of contraception. Throughout history, there has been almost nothing people have worried about more than having sex without fear of consequence. At first sight, the story of contraception seems to be one of progress, from the Ancient Egyptian crocodile-dung pessary to the modern-day condom and contraceptive pill. A closer look, however, shows a pattern of remarkable continuities in the reproductive behaviour of men and women over the last two thousand years. In this paper, I shall attempt to show why traditional male-dominated contraceptive methods still linger on despite the sexual revolution brought about by the invention of the 'pill' in the late 1950s.     

Synchronous diving behavior of Adélie penguins

Synchronizing behavior with other conspecifics has been suggested as serving a function of increased foraging efficiency. However, the potential costs associated with synchronization of behavior have rarely been studied. Adélie penguins Pygoscelis adeliae sometimes dive synchronously in small open waters surrounded by fast sea ice. We examined the diving behavior of three couples and one trio, which were observed to dive synchronously among groups of 12–47 birds for 1.7–4.5 h duration, with time-depth recorders. Timing of diving and surfacing differed slightly between individuals, and one bird tended to initiate diving earlier than the other. Although the duration of the dives differed only slightly between these birds, the maximum depth of the dives differed to a large extent, with one member tending to dive consistently deeper than the other bird in two out of the four cases. Vertical distances between tagged birds in the undulatory phases of the dives (presumed feeding time) were greater than those in the descent and ascent phases, suggesting independent foraging by group members. Duration of the undulatory phase of the dives tended to be shorter in deeper-diving individuals than the others in the synchronously diving group, suggesting a potential cost of reduced feeding time to synchronize diving and surfacing with other birds. A digital video image relating to the article is available at .     

Contribution of 3-Deoxyglucosone as an Intermediate to Browning of Saké

The behaviour of 3-deoxyglucosone (3-D-G) was investigated in the process of browning of Saké, and it was concluded that the browning of Saké involved at least three kinds of browning reactions which were the amino-carbonyl reaction, the caramelization and some other browning reaction by components other than glucose in Saké. The active dicarbonyl compound of 3-D-G was confirmed to act as an important intermediate in both the amino-carbonyl reaction and caramelization. The caramelization was the browning of glucose by itself via 3-D-G, while the amino-carbonyl reaction was the browning of glucose via 3-D-G by the interaction with the amino compounds in Saké. The remainder was, however, independent of glucose and 3-D-G. The temperature coefficient for the rate of the overall browning of Saké was estimated to be 2.8 to 2.9 of Q₁₀ value.     

Studies on Growth Inhibition of Hiochi-bacteria,Specific Saprophytes of Saké

The authors have succeeded in isolating an antibiotic, from the cultured filtrate of Asp. oryzae, responsible for, at least, the majority of the active substances against hiochi-bacteria, as pale yellow crystals of m.p. 152~153°C. It has been proved that this antibiotic is identical with hydroxyaspergillic acid. The minimum concentration for complete inhibition in diluted Saké-peptone medium against true hiochi-bacilli, Lactobacillus homohiochii H-42 and Lactobacillus heterohiochii H-l, was 10 γ/ml, and that against hiochi-lactobacilli H-7 and H-34 20 γ/ml.     

The effect of photoperiodic régime on vernalization of winter wheat

Na ozimé p?enici odr. Hodonínská holice byla studována otázka vlivu fotoperiodického re?imu na pr?běh jarovisace. Polní pokusy ukázaly, ?e krátký den urychluje vývoj, p?sobí-li v dobé jarovisace. Krátký den aplikovaný po jarovisaci ve v?ech p?ípadech vývoj prodlu?oval. P?i umělém osvětlení nízké intensity a v podmínkách jarovisa?ních teplot probíhá jarovisace vět?inou rychleji na dlouhém dni. Jarovisace v temnotě se uskute?ňuje pouze po p?idání glycid?. P?edpokládám, ?e i u zelených rostlin je nahromadění ur?itého mno?ství ergastického materiálu, zejména glycid?, jednou z podmínek pr?běhu jarovisace. Tohoto nahromadění m??e být dosa?eno jednou prodlou?ením osvětlení (v podmínkách optimálních jarovisaěních teplot a p?i umélém osvétlení poměrně nízké intensity), jindy, v polních podmínkách, krátkým dnem vyvolávajícím specifickou, fotoperiodicky kontrolovanou r?stovou reakci inhibující r?st.     

Effect of brousse tigrée on the dynamics of nurse–protégé interactions of a cactus in the Chihuahuan Desert

A nurse–protégé relationship is a frequent facilitation interaction in deserts that allows the recruitment of new individuals of many species. Our aim was to evaluate the relationship of Echinocereus enneacanthus during its life cycle and its nurse plants in the brousse tigrée (tiger bush) vegetation of the Chihuahuan Desert. The population structure of the cactus is skewed toward adult stages, which are commonly found in the bare areas of the brousse tigrée, whereas juveniles are located in the vegetated bands. The vegetation structure and the nurse–protégé relationship were determined using censuses of 19 permanent plots monitored between 2008 and 2019. The differential association of E. enneacanthus with potential nurse plants was evaluated using an interaction network, under the hypothesis of strict association of the seedlings and juveniles with nurse species. In addition, χ² tests and standardized residuals were fitted among likely nurse species, weighted by the cover of the nurse and of the areas without vegetation. The study species, as well as the nurse plants, had an aggregated distribution pattern. The interaction network showed that the frequency of the association with nurse plants decreased as the size of the protégé individuals increased. At the same time, there were differences in the establishment of E. enneacanthus under particular nurse plants; Prosopis glandulosa and Hilaria mutica were the most important. The nurse–protégé relationship for seeds and seedlings is integral to the vegetation bands of the brousse tigrée.     

Summer and winter diapause in pupae of the cabbage butterfly,Pieris melete Ménétriés

The cabbage butterfly, Pieris melete is multivoltine with a pupal summer and winter diapause. Summer and winter diapause are induced principally by relatively long and short daylengths, respectively. The intermediate to relatively short daylengths of autumn permitted some pupae to develop without diapause in the field. A short daylength had a stronger diapause inducing effect than a relatively long one under higher temperatures. The principal sensitive phase for photoperiodic response occurred before the late 3rd larval instar. The critical daylength for wild autumnal populations was between 12h 30min and 12h 40min at an average temperature of 20.5 degrees C. A night interruption by 2h of light averted diapause most effectively when it was placed 10 to 12h after lights-off. High temperatures and long days during summer inhibited the incidence of diapause, suggesting that the occurrence of summer diapause is due to the specific climatic conditions occurring in April and early May, rather than to the high temperatures in summer. This indicates that the butterfly has a cryptic ability to reproduce in summer. High temperatures delayed diapause development, whereas low temperatures enhanced it, indicating that the optimum temperature of diapause development is lower. The diapause regulating mechanisms thus ensure that the species synchronises its development and reproduction with the growth seasons of the host plants and provide the species with a high degree of flexibility in its life cycle.     

Some notes on estimation of the basic homoteneity-coefficient of sets of phytosociological relevés

The formula for calculation of the basic homotoneity-coefficient of sets of phytosociological relevés does not give adequate values for sets of 4 or 3 relevés. Therefore an empirical correction procedure is proposed for the calculation of this coefficient for such small sets of relevés. For sets of 2 relevés the calculation of the basic homotoneity-coefficient gives values equal toSørensen’s coefficient of floristic similarity. A simplification of calculation of the basic homotoneity-coefficient for sets of more than 20 relevés is proposed.