Stratigraphy of the Southern part of the Sergipano Belt, NE Brazil : tectonic implications

A Faixa Sergipana (NE, Brasil) é uma cunha orogenética de direção geral ESE-WNW e que foi polideformada/metamorfisada em consequencia da colisão entre o Macifo Pernambuco- Alagoas, a norte, e o Cráton de São Francisco, a sul, no Ciclo Brasiliano, há cerca de 700-600 Ma, A partir de estudos anteriores em escala regional a faixa e dividida, de sul para norte, em tres domínios litotectônicos longitudinals, respectivamente assemelhados a pilhas de rochas sedimentares e vulcanicas construidas em ambiente cratdnico, miogeoclinal e eugeoclinal separados por falhas reversas, em geral de alto angulo, que indicam transporte de topo para SSW com transcorrgncia associada. Na parte norte da faixa são ainda individualizados dois outros domfnios de rochas fgneas e um domfnio de migmatitos e gnaisses. Modelos divergentes de evolução tectônica foram produzidos para a faixa, com base em interpretações a favor e contra a continuidade lateral entre os metasedimentos. Estudos litoestratigrdficos-estruturais realizados em escala de detalhe (1987-1995) em drea de 4000km2 circundando dois domos gnáissicos de embasamento e englobando a interface entre o craton, miogeoclinal e eugeoclinal, na parte sul da faixa Sergipana, revelam: (1) uma nova litoestratigrafia das rochas depositadas nos dois domínios mais a sul, distinta daquela dos estudos anteriores; (2) evidencias sedimentológicas, estruturais, metamórficas e geofísicas inequívocas a favor da continuidade entre os três domínios, através das suas falhas de borda; (3) a parte superior da seção da cobertura cratonica compreende uma sequencia de argilito, siltito, arenito, arcósio e grauvação lítica, com granulometria crescente para o topo; esta seção passa gradativamente a metasiltito e filito depositados na bacia, onde ocorre sobreposta ao grupo basal e sotoposta a diamictitos e carbonates do grupo superior, todos depositados em tomo dos domos de embasamento que ocupam o nucleo de antiformes regionais; (4) as caracteristicas sedimentológicas e o posicionamento estratigráfico inequívoco da sequência de granulometria crescente para o topo descartam modelos tipo bacia foreland anteriormente adotados para explicar o topo da seção da cobertura cratônica adjacente a Faixa Sergipana. Os dados permitem interpretar que o preenchimento da bacia precursora se deu em regime de sedimentação controlada por tectônica, no qual os domos de embasamento provavelmente atuaram como paleo-altos e as falhas regionais limitantes dos domínios (meta)vulcano-sedimentares sao provdveis falhas normals originais, que foram positivamente invertidas na fase de fechamento da bacia. A origem da parte superior da cobertura cratônica, cuja deve ser atribuída ao soerguimento e erosao de fonte a sul, e os controles tectonicos da sedimentacao, implicam consideravelmente para a evolução da Faixa Sergipana e do Cráton de São Francisco. _________________________________________________________________________________ ABSTRACTThe Sergipano Belt (NE Brazil) is a ESE-WNW trending volcano-sedimentary wedge polydeformed and metamorphosed (700-600Ma) due to the collision of the Pernambuco-Alagoas Massif, to the north, with the São Francisco Craton, to the south, during the Pan-African/Brasiliano orogeny. According to previous, regional-scale studies, the belt comprises three longitudinal lithotectonic domains with cratonic, miogeoclinal and eugeoclinal affinities, respectively from S to N, separated by regional, WNW-ESE trending, generally high-angle thrust-strike slip faults. Divergent tectonic evolution models were produced based on interpretations for and against the lateral continuity between these domains. Detailed stratigraphic-structural analysis from a 1:50,000 scale mapping carried out (1987-1995) in a 4000km2 area encompassing the interface between the three domains and surrounding two basement gneiss domes in the southern part of the belt, revealed: (1) the lithostratigraphy of the rocks deposited in the cratonic and miogeoclinal segments; (2) innequivocal evidence for the sedimentological, structural and metamorphic continuity across the domains boundary faults; (3) the upper section of the sediments deposited in the cratonic domain records the deposition of coarsening-upwards mudstones, siltstones, arkosic sandstones and lithic wackes that spreaded from the craton, to the south, across the craton-basin interface and graded into metasiltites and phyllites towards the miogeoclinal basin, where they occur in the core of a major basement-cored antiform and are overlain by a distinct diamictite formation, thus building up a siliciclastic mcgascquence. The sedimentological characteristics and innequivocal stratigraphic position of these arkosic sandstones and lithic wackes do not fit in previously suggested thrust-fold belt/foreland basin models; (4) very strong evidence for the miogeoclinal and eugeoclinal domains being also continuous across their boundary faults, allowing to erect a new stratigraphic template for the Sergipano Belt. The data allow to interpret that sedimentation was tectônicaly controlled by the basement domes and normal faults likely to have been inverted during the closure of the basin. The origin of the upper section of the sediments deposited in the cratonic domain and the tectonic controls of the sedimentation have relevant implications for the evolution of both the Sergipano Belt and the São Francisco Craton

Phase II study of second-line therapy with DTIC, BCNU, cisplatin and tamoxifen (Dartmouth regimen) chemotherapy in patients with malignant melanoma previously treated with dacarbazine

This study assessed response rates to combination dacarbazine (DTIC), BCNU (carmustine), cisplatin and tamoxifen (DBPT) chemotherapy in patients with progressive metastatic melanoma previously treated with DTIC, as an evaluation of DBPT as a second-line regimen, and as an indirect comparison of DBPT with DTIC. Thirty-five consecutive patients received DBPT. The patients were divided into two groups. Group 1 comprised 17 patients with progressive disease (PD) on DTIC + tamoxifen therapy who were switched directly to DBPT. Group 2 comprised 18 patients not immediately switched to DBPT and included patients who had either a partial response (PR; one patient) or developed stable disease (SD; four patients) with DTIC, or received adjuvant DTIC (nine patients). All except four patients had received tamoxifen at the time of initial DTIC treatment. Median times since stopping DTIC were 22 days (range 20–41) and 285 days (range 50–1240) in Groups 1 and 2 respectively. In Group 1, one patient developed SD for 5 months and the remainder had PD. In Group 2, there were two PRs, four patients with SD (4, 5, 6, and 6 months), and 11 with PD. These results indicate that the DBPT regimen is not of value in melanoma primarily refractory to DTIC. There were responses in patients not directly switched from DTIC to DBPT, suggesting combination therapy may be of value in a small subgroup of melanoma patients. © 2000 Cancer Research Campaig

Repression of mesodermal fate by foxa, a key endoderm regulator of the sea urchin embryo

The foxa gene is an integral component of the endoderm specification subcircuit of the endomesoderm gene regulatory network in the Strongylocentrotus purpuratus embryo. Its transcripts become confined to veg2, then veg1 endodermal territories, and, following gastrulation, throughout the gut. It is also expressed in the stomodeal ectoderm. gatae and otx genes provide input into the pregastrular regulatory system of foxa, and Foxa represses its own transcription, resulting in an oscillatory temporal expression profile. Here, we report three separate essential functions of the foxa gene: it represses mesodermal fate in the veg2 endomesoderm; it is required in postgastrular development for the expression of gut-specific genes; and it is necessary for stomodaeum formation. If its expression is reduced by a morpholino, more endomesoderm cells become pigment and other mesenchymal cell types, less gut is specified, and the larva has no mouth. Experiments in which blastomere transplantation is combined with foxa MASO treatment demonstrate that, in the normal endoderm, a crucial role of Foxa is to repress gcm expression in response to a Notch signal, and hence to repress mesodermal fate. Chimeric recombination experiments in which veg2, veg1 or ectoderm cells contained foxa MASO show which region of foxa expression controls each of the three functions. These experiments show that the foxa gene is a component of three distinct embryonic gene regulatory networks

Evidence for the influence of conspecific chemical cues on Aphthona nigriscutis (Coleoptera: Chrysomelidae) behaviour and distribution.

Abstract. Although the distribution of biological control agents may have a significant effect upon their impacts, the mechanisms regulating these distributions are often unknown. Such is the case with Aphthona nigriscutis, a classical biological control agent of leafy spurge in North America. These beetles assume aggregated distributions at some sites but disperse rapidly at others. The potential influence of plant and insect-factors upon aggregation and dispersal was investigated to try to explain these observations. Male beetles produce a putative aggregation pheromone. Responses of conspecifics to male-associated cues are greater when beetles are feeding on host plants. Densities of beetle groups greatly impact their attractiveness. Males are more sensitive to dispersal cues and females are more sensitive to congregation cues

Oral contraceptive use and risk of melanoma in premenopausal women

Melanoma has been increasing in white populations. Incidence rates rise steeply in women until about age 50, suggesting oestrogen as a possible risk factor. Oestrogens can increase melanocyte count and melanin content and cause hyperpigmentation of the skin. We examined prospectively the association between oral contraceptive (OC) use and diagnoses of superficial spreading and nodular melanoma among 183 693 premenopausal white women in the Nurses’ Health Study (NHS) and the Nurses’ Health Study II (NHS II) cohorts. One hundred and forty six cases were confirmed in NHS during follow-up from 1976 to 1994, and 106 cases were confirmed in NHS II from 1989 to 1995. Skin reaction to sun exposure, sunburn history, mole counts, hair colour, family history of melanoma, parity, height and body mass index were also assessed and included in logistic regression models. A significant twofold increase in risk of melanoma (relative risk (RR) = 2.0, 95% confidence interval (CI) 1.2–3.4) was observed among current OC users compared to never users. Risk was further increased among current users with 10 or more years of use (RR = 3.4, 95% CI 1.7–7.0). Risk did not appear elevated among past OC users, even among those with longer durations of use, and risk did not decline linearly with time since last use. In conclusion, risk of premenopausal melanoma may be increased among women who are current OC users, particularly among those with longer durations of use. Further research is needed to determine whether low-dose oestrogen pills in particular are associated with an increase in risk and to describe possible interactions between OC use and sun exposure or other risk factors for melanoma. © 1999 Cancer Research Campaig

Ligand-Receptor Interactions

The formation and dissociation of specific noncovalent interactions between a variety of macromolecules play a crucial role in the function of biological systems. During the last few years, three main lines of research led to a dramatic improvement of our understanding of these important phenomena. First, combination of genetic engineering and X ray cristallography made available a simultaneous knowledg of the precise structure and affinity of series or related ligand-receptor systems differing by a few well-defined atoms. Second, improvement of computer power and simulation techniques allowed extended exploration of the interaction of realistic macromolecules. Third, simultaneous development of a variety of techniques based on atomic force microscopy, hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or flexible transducers yielded direct experimental information of the behavior of single ligand receptor bonds. At the same time, investigation of well defined cellular models raised the interest of biologists to the kinetic and mechanical properties of cell membrane receptors. The aim of this review is to give a description of these advances that benefitted from a largely multidisciplinar approach

Perspectives on Continental Rifting Processes From Spatiotemporal Patterns of Faulting and Magmatism in the Rio Grande Rift, USA

Analysis of spatiotemporal patterns of faulting and magmatism in the Rio Grande rift (RGR) in New Mexico and Colorado, USA, yields insights into continental rift processes, extension accommodation mechanisms, and rift evolution models. We combine new apatite (U‐Th‐Sm)/He and zircon (U‐Th)/He thermochronometric data with previously published thermochronometric data to assess the timing of fault initiation, magnitudes of fault exhumation, and growth and linkage patterns of rift faults. Thermal history modeling of these data reveals contemporaneous rift initiation at ca. 25 Ma in both the northern and southern RGR with continued fault initiation, growth, and linkage progressing from ca. 25 to ca. 15 Ma. The central RGR, however, shows no evidence of Cenozoic fault‐related exhumation as observed with thermochronometry and instead reveals extension accommodated through Late Cenozoic magmatic injection. Furthermore, faulting in the northern and southern RGR occurs along an approximately north‐south strike, whereas magmatism in the central RGR occurs along the northeast to southwest trending Jemez lineament. Differences in deformation orientation and rift accommodation along strike appear to be related to crustal and lithospheric properties, suggesting that rift structure and geometry are at least partly controlled by inherited lithospheric‐scale architecture. We propose an evolutionary model for the RGR that involves initiation of fault‐accommodated extension by oblique strain followed by block rotation of the Colorado Plateau, where extension in the RGR is accommodated by faulting (southern and northern RGR) and magmatism (central RGR). This study highlights different processes related to initiation, geometry, extension accommodation, and overall development of continental rifts.Plain Language SummaryWe identify patterns of faulting and volcanism in the Rio Grande rift (RGR) in the western United States to better understand how continental rifts evolve. Using methods for documenting rock cooling ages (thermochronology), we determined that rifting began around 25 million years ago (Ma) in both the northern and southern RGR. Rift faults continued to develop and grow for another 10 to 15 million years. The central RGR, however, shows that rift extension occurred through volcanic activity both as eruptions at the surface and as magma injection below the surface since ~15 Ma. Interestingly, RGR faulting in the north and south parts of the rift occurs on a north‐south line, while volcanism in the central RGR is along a northeast to southwest line. The differences in the location and orientation of faulting and volcanic activity may be related to the thickness of the lithosphere beneath different parts of the rift. Using these patterns of faulting and magmatism, we propose the RGR evolved through a combination of (1) oblique strain—extension diagonal to the rift and (2) block rotation—where the Colorado Plateau is the rotating block. This detailed study highlights different processes related to the accommodation of extension and the overall development of continental rifts.Key PointsInitiation of the Rio Grande rift appears to be synchronous ~25 Ma and does not support a northward propagation modelExtension is accommodated by faulting in the northern and southern Rio Grande rift and by magmatic injection in the central Rio Grande riftDifferent rift accommodation mechanisms may be controlled by preexisting weaknesses and lithospheric properties (i.e., thickness)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152704/1/tect21226.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152704/2/wrcr21226-sup-00001-2019TC005635-SI.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152704/3/tect21226_am.pd

Combination chemotherapy with or without s.c. IL-2 and IFN-α: results of a prospectively randomized trial of the Cooperative Advanced Malignant Melanoma Chemoimmunotherapy Group (ACIMM)

The purpose of this randomized trial was to evaluate the efficacy of combination chemoimmunotherapy compared with chemotherapy alone. A total of 124 patients were randomized to receive intravenous cisplatin (35 mg m−2, days 1–3), carmustine (150 mg m−2, day 1, cycles 1 and 3 only), dacarbacine (220 mg m−2, days 1–3) and oral tamoxifen (20 mg m−2, daily) in combination with (n=64) or without (n=60) sequential subcutaneous IL-2 and IFN-α. In those patients who received sequential immunotherapy, each cycle of chemotherapy was followed by outpatient s.c. IL-2 (10×106 IU m−2, days 3–5, week 4; 5×106 IU m−2, days 1, 3, 5, week 5) and s.c. IFN-α (5×106 IU m−2, day 1, week 4; days 1, 3, 5, week 5). The overall response rate of patients treated with the combination of chemotherapy and IL-2/IFN-α was 34.3% with seven complete responses (10.9%) and 15 partial responses (23.4%). In patients treated with chemotherapy, only, the overall response rate was 29.9% with eight complete responses (13.3%) and 10 partial responses (16.6%). There was no significant difference in median progression free survival (0 months vs 4 months) and in median overall survival (12 months vs 13 months) for combined chemoimmunotherapy and for chemotherapy, respectively

Genome-wide pharmacogenomic analysis of response to treatment with antipsychotics

Schizophrenia is an often devastating neuropsychiatric illness. Understanding the genetic variation affecting response to antipsychotics is important to develop novel diagnostic tests to match individual schizophrenic patients to the most effective and safe medication. Here we use a genomewide approach to detect genetic variation underlying individual differences in response to treatment with the antipsychotics olanzapine, quetiapine, risperidone, ziprasidone and perphenazine. Our sample consisted of 738 subjects with DSM-IV schizophrenia who took part in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE). Subjects were genotyped using the Affymetrix 500K genotyping platform plus a custom 164K chip to improve genomewide coverage. Treatment outcome was measured using the Positive and Negative Syndrome Scale (PANSS). Our criterion for genomewide significance was a pre-specified threshold that ensures, on average, only 10% of the significant findings are false discoveries. The top statistical result reached significance at our pre-specified threshold and involved a SNP in an intergenic region on chromosome 4p15. In addition, SNPs in ANKS1B and CNTNAP5 that mediated the effects of olanzapine and risperidone on Negative symptoms were very close to our threshold for declaring significance. The most significant SNP in CNTNAP5 is nonsynonymous, giving rise to an amino acid substitution. In addition to highlighting our top results, we provide all p-values for download as a resource for investigators with the requisite samples to carry out replication. This study demonstrates the potential of GWAS to discover novel genes that mediate effects of antipsychotics, which eventually could help to tailor drug treatment to schizophrenic patients