Um sobrevôo no "Caso Marie Curie": um experimento de antropologia, gênero e ciência

O presente artigo visa fazer uma releitura do "Caso Marie Curie" sob o signo do acontecimento. O intuito, assim, é explorar relações constituintes da controvérsia que se desdobrou no prêmio Nobel de 1903, que laureou a descoberta da radioatividade e de elementos radioativos. A porta de entrada, para tal empreitada, serão as mediações entre as relações de gênero e os não-humanos mobilizados nos laboratórios. Baseado nessas mediações, descrevo a diferença de possibilidades masculino/feminina em fazer-existir a Natureza em relação ao poder que a definição de gênero dá a uns em detrimento de outros, mas também como ao fazer-existir a radioatividade constituiu-se um devir, que fez essa relação gaguejar, mudando-a de sentido. O "Caso Marie Curie" torna imediatamente inseparável dois domínios: tanto o envolvimento das relações de gênero na produção científica quanto o envolvimento da ciência nas relações de gênero. Esse acontecimento ressoa para abordagens antropológicas e feministas da ciência. Assim, coloco-as em discussão na medida em que as relações de poder fizeram-me respeitar o devir que o ofício da cientista pôs em cena: a radioatividade.

The food spectrum of the cardinal - tetra (Paracheirodon axelrodi, Characidae) in its natural habitat

The cardinal tetra (Paracheirodon axelrodi) is the most intensively commercialized ornamental fish from the Rio Negro Basin (Amazonas State, Brasil). Analysis of the stomach and gut contents of fish caught in their natural habitats show conclusively that the cardinal is essentially a predator, feeding on the mesofauna that adheres to submerged litter, roots and waterplants. Microcrustacea and chironomid larvae (Diptera) were the most frequently ingested prey, while algae intake was relatively infrequent. It is argued that the relatively small size of the cardinals captured in their natural habitat is due to the annual migrations imposed by the inundation cycles, rather than to resource limitation, because it is known from earlier investigations of similar habitats, that these plant substrates are densely colonized by the aquatic mesofauna. Cardinals raised in captivity are larger and have higher rates of growth.

Tolerance to temperature, pH, ammonia and nitrite in cardinal tetra, Paracheirodon axelrodi, an amazonian ornamental fish

Poor water quality condition has been pointed out as one of the major causes for the high mortality of ornamental fishes exported from the state of Amazonas, Brazil. The purpose of the current study was to define water quality standards for cardinal tetra (Paracheirodon axelrodi), by establishing the lower and higher for lethal temperature (LT50), lethal concentration (LC50) for total ammonia and nitrite and LC50 for acid and alkaline pH. According to the findings, cardinal tetra is rather tolerant to high temperature (33.3 ºC), to a wide pH range (acid pH=2.9 and alkaline pH=8.8) and to high total ammonia concentration (23.7 mg/L). However, temperatures below 19.6 ºC and nitrite concentrations above 1.1 mg/L NO2- may compromise fish survival especially during long shipment abroad.

Aspectos históricos da visita de Marie Sklodowska Curie a Belo Horizonte

In the year 2011 it is celebrated the Marie Sklodowska Curie Nobel Prize centenary and the International Year of Chemistry. However, it is not generally known that Marie Sklodowska Curie, one of the greatest scientists of all time, visited Belo Horizonte, state of Minas Gerais, Brazil. She arrived by train at Belo Horizonte city on 16 August 1926, coming from Rio de Janeiro and accompanied by her daughter Irène Joliot-Curie. The scientists visited the Institute of Radium of Belo Horizonte. The approach in this work emphasizes the presence of Marie Sklodowska Curie in Belo Horizonte, exploring the admiration and respect that people had for her.

Isospora bocamontensis (Protozoa: Apicomplexa) in captive yellow cardinal Gubernatrix cristata (Passeriformes: Emberezidae)

The yellow cardinal (Gubernatrix cristata) is a passerine found in southern Brazil, especially along the border with Uruguay and Argentina. It is an endangered species and its population is decreasing. Among the parasites that affect passerines, the genus Isospora is the most easily found in both captive and free-living birds. This parasite commonly causes injury to the intestinal tissue and could occasionally affect other organs. In this work we examined the occurrence of coccidiosis in captive yellow cardinals and its association with factors such as sex, use of parasiticides, type of enclosure, contact with feces, type of food and cleaning frequency. We collected fecal samples of 45 yellow cardinals, healthy and kept in captivity, in late afternoon at the end of the reproductive period. The examination showed parasitic infection by Isospora bocamontensis in 44.5% of the birds. This infection is not influenced by the sex of birds, but is significantly affected by the type of enclosure, contact with the feces, use of parasiticides, type of food and cleaning frequency. The results indicate that to keep yellow cardinals captive, these factors must be observed.

CARDINAL TEMPERATURES FOR GERMINATION OF THE MEDICINAL ANDDESERT PLANT, Calotropis procera

ABSTRACT Calotropis procera, Apocynaceae, is a wild perennial shrub that originated in the Persian deserts. It is known to provide key resources in degraded ecosystems to about 80 animal species. C. procera is regenerated by seed and produces lots of small seeds that are dispersed by wind; nonetheless, its density is very low. The purpose of this study is to estimate the cardinal temperatures including the base, optimum, and maximum temperatures of Calotropis procera looking at two different ecotypes in the Iranian desert. The germination behavior of C. procera seeds was tested at temperature regimens of 0, 5, 10, 15, 20, 25, 30, 35 and 40oC and was analyzed using linear regression models. The rate of germination increased between base and optimum thermal conditions, and decreased between optimum and maximum thermal conditions. The base, optimum and maximum temperatures for germination of C. procera seeds were estimated at 19.10, 30.75 and 47.80 oC for the Fars and 20.00, 31.82 and 49.69oC for the Zahedan desert, respectively. Temperature and germination were rated to determine the seeding dates of the C. procera. Overall, cardinal temperatures for germination were dependent on local climate characteristics for the range of adaptations in plant growth of the given species.

Thr(118)Met amino acid substitution in the peripheral myelin protein 22 does not influence the clinical phenotype of Charcot-Marie-Tooth disease type 1A due to the 17p11.2-p12 duplication

The Thr(118)Met substitution in the peripheral myelin protein 22 (PMP22) gene has been detected in a number of families with demyelinating Charcot-Marie-Tooth (CMT1) neuropathy or with the hereditary neuropathy with liability to pressure palsy, but in none of them has it consistently segregated with the peripheral neuropathy. We describe here a CMT1 family (a 63-year-old man, his brother and his niece) in which two mutations on different chromosomes were found in the PMP22 gene, the 17p duplication, detected by fluorescent semiquantitative polymerase chain reaction (PCR) of microsatellite markers localized within the duplicated region on chromosome 17p11.2-p12, and the Thr(118)Met substitution, detected by direct sequencing the four coding exons of the PMP22 gene. A genotype/phenotype correlation study showed that the neuropathy segregates with the duplication and that the amino acid substitution does not seem to modify the clinical characteristics or the severity of the peripheral neuropathy. We did not find any evidence to characterize this substitution as a polymorphism in the population studied and we propose that the high frequency reported for this point mutation in the literature suggests that the Thr(118)Met substitution may be a hotspot for mutations in the PMP22 gene.