Influence of an adsorbing polymer in the aging dynamics of Laponite clay suspensions

Clay-polymer dispersions in aqueous solutions have attracted a great interest in recent years due to their industrial applications and intriguing physical properties. Aqueous solutions of bare Laponite particles are known to age spontaneously from an ergodic state to a non ergodic state in a time varying from hours to months depending on Laponite concentration. When a polymer species like Polyethylene Oxide (PEO) is added to the solution, it weakly adsorbs on clay particle surfaces modifying the effective interaction potential between Laponite particles. A dynamic light scattering study, varying polymer concentration at fixed polymer molecular weight (Mw=200.000 g/mol), has been performed in order to understand the effect of polymer on the aging dynamics of the system. The results obtained show that arresting phenomena between clay particles are hindered if PEO is added and consequently the aging dynamics slows down with increasing PEO concentration. This process is possibly due to the progressive coverage of the clay surface by polymers that grow with increasing PEO concentration and may lead to steric stabilization.Comment: 13 pages, 6 figures, manuscript accepted for publication on Philosophical Magazin

Routes to gelation in a clay suspension

The gelation of water suspension of a synthetic clay (Laponite) has been studied by dynamic light scattering in a wide range of clay weight concentration (Cw = 0.003-0.031). At variance with previous determination, indicating a stable liquid phase for Cw < Cw*=0.015-0.018, we find that the gelation takes actually place in the whole examined Cw range. More importantly, we find that Cw* marks the transition between two different routes to gelation. We hypothesize that at low concentration Laponite suspension behaves as an attractive colloid and that the slowing down of the dynamics is attained by the formation of larger and larger clusters while at high concentration the basic units of the gel could be the Debye Huckel spheres associated to single Laponite plates.Comment: 5 pages, 4 figure

More on phase diagram of Laponite

The phase diagram of a charged colloidal system (Laponite) has been investigated by dynamic light scattering in a previously unexplored range of salt and clay concentrations. Specifically the clay weight and salt molar concentrations have been varied in the ranges Cw=0.004- 0.025, Cs=(1x 10^-3- 5x 10^-3) M respectively. As in the case of free salt water samples (Cs= 1x 10^-4 M) an aging dynamics towards two different arrested phases is found in the whole examined Cw and Cs range. Moreover a transition between these two different regimes is found for each investigated salt concentration. It is clear from these measurements that a revision of the phase diagram is necessary and a new "transition" line between two different arrested states is drawn.Comment: 16 pages, 5 figures, submitted to Langmui

Distribuição e tamanho populacional de papagaios (Amazona spp.) da Mata Atlântica : uma análise estatística com integração de dados

Abundância e área de distribuição são duas variáveis de estado cruciais para entendimento das populações, bem como para a categorização de ameaça das espécies pela IUCN. Nesse trabalho, focamos a atenção em quatro espécies da família Psittacidae3⁄4uma das mais ameaçadas dentre as aves3⁄4Amazona brasiliensis, A. pretrei, A. rhodocorytha e A. vinacea. No primeiro capítulo, estimamos o tamanho populacional global de A. vinacea a partir de contagens replicadas e discutimos as fontes de incerteza associadas às contagens e estimativas e como minimizá-las. No segundo capítulo, mapeamos a área de distribuição global de A. vinacea a partir de integração de dados de pesquisa com dados de plataformas de ciência cidadã e discutimos como levar em consideração as especificidades de cada conjunto de dados, o esforço amostral, as covariáveis de sítio e a autocorrelação espacial nas análises. No terceiro capítulo, reunimos toda a informação disponível na literatura sobre o tamanho populacional das espécies A. brasiliensis, A. pretrei, A. rhodocorytha e A. vinacea, e mapeamos a área distribuição para cada espécie. Dentre as quatro espécies estudadas, A. pretrei possui a série temporal mais longa de monitoramento e as maiores contagens3⁄4em torno de 20.000 indivíduos. A. vinacea é a única espécie com uma estimativa estatística do tamanho populacional3⁄4em torno de 8.500 indivíduos para 2017. O tamanho das áreas estimadas variou de 15.000 km2 para A. brasiliensis até 434.000 km2 para A. vinacea. A. rhodocorytha é a espécie que mais urgentemente necessita de estudos de tamanho populacional, já que não conta com programa de monitoramento. O uso de dados de ciência cidadã se mostrou uma ferramenta muito útil para mapeamento de distribuição de espécies. Entretanto, para obter estimativas mais informativas, é crucial que a amostragem e análises levem em consideração a incerteza associada à essas estimativas.Population size and geographic range are key predictors of extinction risk and are critical to listing species in IUCN threat categories. Here we focused our attention on four Psittacidae species one of the most threatened bird families Amazona brasiliensis, A. pretrei, A. rhodocorytha, and A. vinacea. In the first chapter, we estimated the A. vinacea’s global population size based on replicated counts. We discussed the uncertainty sources associated with the counts and estimates and how to minimize them. In the second chapter, we map the A. vinacea’s geographic range based on the integration of research-based data with citizen-science datasets and we demonstrate how to include the sampling effort information, spatial autocorrelation, and site covariates to obtain more precise and more accurate estimates. In the third chapter, we compiled abundance estimates and counts and estimated the geographic range of species A. brasiliensis, A. pretrei, A. rhodocorytha e A. vinacea. Comparing the four species, A. pretrei is the one with the longest time series of roost counts e the highest counts (~20,000 individuals). A. vinacea is the only species with a statistical estimate of abundance (~8,500 individuals). Estimated range areas varied from 15,000 km2 for A. brasiliensis to 434,000 km2 for A. vinacea. A. rhodocorytha is the species that most urgently need studies about population size and geographic range. The integration of citizen-science datasets with research data is a useful tool to map the geographic range of species. However, to obtain more informative estimates, it is crucial that the sampling and the analysis considering the uncertainty associated with the estimates

Distribuição e abundância de Amazona vinacea (Papagaio-de-peito-roxo) no oeste de Santa Catarina

Esse trabalho oferece uma avaliação da abundância do papagaio-de-peito-roxo (Amazona vinacea) para 2016 e 2017, combinando contagens em dormitórios ao longo de toda a distribuição da espécie, em escala global, com amostragens replicadas em dormitórios na região oeste de Santa Catarina (WSC), em escala local, Brasil. As contagens em escala global resultaram em 3888 e 4066 indivíduos em 2016 e 2017, respectivamente. As estimativas para o WSC foram de 945 ± 50 e 1393 ± 40 para os mesmos dois anos. Não foi observada nenhuma evidência de crescimento populacional de 2016 para 2017, pois o acréscimo no número de indivíduos foi acompanhado por aumento do esforço amostral em ambas escalas. Quando extrapolamos a abundância no WSC para toda a área de distribuição da espécie, segundo a IUCN, e pressupondo densidade homogênea, obtivemos valores que estão acima da contagem na escala global, mas dentro da mesma ordem de magnitude. Nosso resultado oferece uma base sólida para afirmar que o tamanho populacional global de A. vinacea é de milhares de indivíduos, mas não dezenas de milhares. Realizamos um esforço sistemático para considerar as principais fontes de incerteza na estimativa de abundância da espécie. Cada contagem, tanto na escala local quanto na global, incluíram visitas em todos os dormitórios conhecidos dentro de um intervalo de 10 dias, evitando duplas contagens devido ao movimento dos papagaios entre dormitórios. No WSC, a abundância foi estimada usando um N-Mixture Model implementado em contexto Bayesiano. Apesar de nossa estimativa de tamanho populacional e de área de distribuição serem maiores do que as consideradas pela IUCN, sugerimos que A. vinacea permaneça na categoria “Em Perigo”, até que sejam realizados estudos sobre tendência populacional.We offer an assessment of Vinaceous parrot (Amazona vinacea) abundance in 2016 and 2017, combining roost counts over the whole range of the species, with a replicated survey of roosts at the local scale, in western Santa Catarina state (WSC), Brazil. The whole range counts amounted to 3888 and 4066 individuals in 2016 and 2017, respectively. The WSC estimates were 945 ± 50 and of 1393 ± 40 individuals, for the same two years. We found no evidence of population growth from 2016 to 2017 because the increase in numbers is accompanied by an increase in observation effort both in WSC and at the whole-range scale. When extrapolating the WSC abundance estimate to the whole IUCN extant range of the species under the simplifying assumption of homogenous population density, we obtain values above the whole-range counts, but within the same order of magnitude. Such result offers a sound basis for putting the global population size of A. vinacea in the thousands of individuals, but not in the tens of thousands of individuals. We made a systematic effort to address key sources of uncertainty in parrot abundance estimation. Each count, at the local or whole-range scale, includes visits to all relevant roosts within less than ten days time to avoid double counting due to movement between roosts. At the local scale, we estimated abundance using an N-Mixture Model of replicated count data, implemented in a Bayesian framework. Even though we estimate a larger population size and a bigger geographic range that those currently reported by the IUCN, we suggest that A. vinacea should remain in the ‘Endangered’ IUCN threat category, pending further investigation of population trends

Insulin Action on Polyunsaturated Phosphatidic Acid Formation in Rat Brain: An “In Vitro” Model with Synaptic Endings from Cerebral Cortex and Hippocampus

The highly efficient formation of phosphatidic acid from exogenous 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG) in rat brain synaptic nerve endings (synaptosomes) from cerebral cortex and hippocampus is reported. Phosphatidic acid synthesized from SAG or 1,2-dipalmitoylsn-glycerol (DPG) was 17.5 or 2.5 times higher, respectively, than from endogenous synaptosomal diacylglycerides. Insulin increased diacylglycerol kinase (DAGK) action on endogenous substrate in synaptic terminals from hippocampus and cerebral cortex by 199 and 97%, respectively. Insulin preferentially increased SAG phosphorylation from hippocampal membranes. In CC synaptosomes insulin increased phosphatidic acid (PA) synthesis from SAG by 100% with respect to controls. Genistein (a tyrosine kinase inhibitor) inhibited this stimulatory insulin effect. Okadaic acid or cyclosporine, used as Ser/Threo protein phosphatase inhibitors, failed to increase insulin effect on PA formation. GTPcS and particularly NaF were potent stimulators of PA formation from polyunsaturated diacylglycerol but failed to increase this phosphorylation when added after 5 min of insulin exposure. GTPcS and NaF increased phosphatidylinositol 4,5 bisphosphate (PIP2) labeling with respect to controls when SAG was present. On the contrary, they decreased polyphosphoinositide labeling with respect to controls in the presence of DPG. Our results indicate that a DAGK type 3 (DAGKe) which preferentially, but not selectively, utilizes 1-acyl-2-arachidonoyl-sn-glycerol and which could be associated with polyphosphoinositide resynthesis, participates in synaptic insulin signaling. GTPcS and NaF appear to be G protein activators related to insulin and the insulin receptor, both affecting the signaling mechanism that augments phosphatidic acid formation.Fil: Zulian, Sandra Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Ilincheta, Monica Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

Possible contributions of the homoeopathic model to humanization of medical training

Em virtude da valorização dos aspectos técnico-científicos no modelo biomédico, aspectos subjetivos da individualidade foram desprezados, tornando a medicina moderna desumanizada e reducionista na abordagem do processo de adoecimento humano. Com o intuito de resgatar a relação médico-paciente e a atenção integral ao indivíduo enfermo, com nítidos reflexos na qualidade e eficácia dos serviços prestados, a preocupação com a humanização da saúde passou a ser uma prioridade dos sistemas públicos, com a implantação de iniciativas nos diversos níveis de atenção. Desta forma, propostas humanísticas estão sendo incorporadas à formação médica nos cursos de graduação em Medicina e na rede de Atenção Básica em Saúde, visando contemplar, entre outros aspectos, "a compreensão dos determinantes sociais, culturais, comportamentais, psicológicos, ecológicos, éticos e legais, nos níveis individual e coletivo do processo saúde-doença". Neste contexto, o modelo homeopático, por aplicar em sua prática clínica diária uma abordagem semiológico-terapêutica individualizante e humanística na compreensão do processo saúde-doença e no tratamento das enfermidades, valorizando os determinantes éticos, filosóficos, antropológicos, psicológicos e socioambientais, poderia contribuir de forma adjuvante e complementar a humanização da formação médica, desde que seus preceitos sejam incorporados de forma regular e gradativa ao processo ensino-aprendizagem das instituições públicas e acadêmicas.To the extent that technical and scientific aspects of the biomedical model assumed increasing importance, subjective characteristics of individuality were neglected, and modern medicine became dehumanized and narrow-minded in its approach to the processes involved in human illness. A current priority for government-run health systems is the determination to reclaim the physician-patient relationship, with comprehensive concern for patients and a clear effect on the quality and effectiveness of the services provided in an effort to achieve a more humane health system. Several new initiatives have been implemented at different levels of care. Humane propositions are thus being incorporated into medical training, in both undergraduate education and the public primary care system, with the aim of understanding the social, cultural, behavioral, psychological, environmental, ethical, and legal determinants of the health-disease process at the individual and community levels. In daily clinical practice, the homeopathic model applies a humane and individualized semiological-therapeutic approach to understanding the health-disease process and treatment of diseases, with attention to the value of ethical, philosophical, anthropological, and socio-environmental determinants and thus the potential for contributing positively to assisting and complementing medical education, as long as the model's principles are progressively incorporated into the teaching and learning process of public and academic institutions

Struktur Ruang Obyek Wisata di Kecamatan Ngargoyoso Kabupaten Karamganyar

Penelitian ini dilakukan di daerah Kecamatan Ngargoyoso Kabupaten Karanganyar yang mempunyai banyak obyek wisata. Penelitian ini secara khusus mengambil di dua desa yaitu Desa Berjo dan Desa Girimulyo yang berada di Kecamatan Ngargoyoso terdapat obyek wisata budaya dan obyek wisata alam. Tujuan penelitian ini untuk (1) mengetahui potensi obyek wisata yang ada di Kecamatan Ngargoyoso Kabupaten Karanganyar dengan mengklasifikasikan potensi internal, potensi eksternal, dan potensi gabungan serta untuk (2) mengetahui arahan struktur ruang obyek wisata. metode yang digunakan dalam penelitian ini adalah metode survei dan analisi data. Metode survei dilakukan untuk memperoleh data dari olaki obyek wisata dengan wawancara pengunjung, pegawai dinas pariwisata dan pengelola obyek wisata. Pengumpulan data juga dilakukan melalui beberapa instansi pemerintah yang terkait didukung dengan data primer data sekunder dan observasi langsungan di lapangan. Analisis yang digunakan yaitu analisis klasifikasi untuk menentukan tingkat potensi internal obyek wisata, potensi ekstrenal obyek wisata, dan potensi gabungan obyek wisata. Obyek wisata yang diteliti meliputi empat obyek wisata yaitu Obyek Wisata Candi Sukuh, Air Terjun Jumog, Air Terjun Parang Ijo, dan Telaga Madirda. Hasil penelitian menunjukan bahwa obyek wisata yang memiliki potensi internal sedang berdasarkan skoring yaitu Candi Sukuh, Air Terjun Jumog dan Air Terjun Parang Ijo, sedangkan untuk Telaga Madirda memiliki potensi internal rendah. Obyek wisata yang memiliki potensi ekstrenal tinggi berdasarkan skroing yaitu Air Terjun Jumog, untuk Candi Sukuh dan Air Terjun Parang Ijo memiliki potensi sedang, sedangkan Telaga madirda memiliki potensi rendah. Obyek wisata yang potensi skor tinggi menjadi pusat struktur ruang pariwisata seperti Air Terjun Jumog. Hasil yang rendah akan menjadi cabang dari pusat struktur ruang obyek wisata yaitu Candi Sukuh dan Telaga Madirda

“Similia Similibus Curentur”: The scientific grounding of the homeopathic therapeutic principle through the systematic study of the rebound effect of modern drugs

• Homeopathy employs the principle of therapeutic similitude as a method of treatment. • Primary action of drugs is followed by secondary and opposite reaction of the organism. • This secondary and opposite reaction of the organism is namely the rebound effect of drugs. • Homeopathy employs the rebound effect of drugs in a therapeutic way