17 research outputs found
Peak-to-peak dynamics in food chain models
No full textWe show in this paper that the chaotic regimes of many food chain models often enjoy a very peculiar property, known as peak-to-peak dynamics. This means that the maximum (peak) density of the populations of any trophic level can be easily forecasted provided the last two peaks of the same population are known. Moreover, extensive simulation shows that only the last peak is needed if the forecast concerns the population at the top of the food chain and that peaks variability often increases from bottom to top. All these findings bring naturally to the conclusion that top populations should be sampled in order to have higher chances to detect peak-to-peak dynamics. The analysis is carried out by studying ditrophic food chain models with seasonally varying parameters, tritrophic food chain models with constant parameters, and more complex food chain and food web models
Can attention be taught? Interspecific attention by dogs (Canis familiaris) performing obedience tasks.
No full textIn the context of dog training it would be of utmost importance to understand the mechanisms that control how attention to humans is allocated by dogs, and how this can be modified by training. This study aimed at characterising the patterns of attention paid to their handler by dogs with different training level, while performing typical obedience tasks in conditions of increasing difficulty. The study involved 64 dogs, classified as expert (completed an obedience course of 6 months, N = 20), intermediate (in training, N = 21) and novice (no training received, N = 23). In the experiment, the handler had to make the dog perform a sequence of three exercises. As first exercise (stay), handlers had to obtain a waiting posture by the dog, step back by 2.5 m and wait 30 s. The following two exercises were identical to the stay, but respectively a bowl with some food (food) and a toy (toy), were placed close to the dog before asking the desired waiting posture. The average duration of gazes (GL) and the frequency of gaze shifts towards the handler (GF) were collected in the two minutes preceding the exercises (baseline attention) and while the dogs were performing the requested exercises. In baseline GL was affected by the dog’s sex (F2,57 = 4.98, P = 0.011, GLM anova), being highest in intact females, and training level (F2,57 = 5.27, P = 0.008) being highest in expert dogs. During obedience exercises GL was affected by the exercise (F2,158 = 11.57, P < 0.001) being highest in stay, and by the training level (F2,158 = 25.02, P < 0.001), being highest in expert and lowest in novice dogs. The frequency of gaze shifting was affected by an exercise*sex interaction (F2,154 = 2.48, P = 0.046), with intact females showing higher GF in toy than all other exercise*sex combination. Moreover, GF was affected by the dog’s training level (F2,154 = 6.64, P = 0.002), being highest in novice dogs. Different mechanisms could contribute to explain our results, including direct effects of training on interspecific attention patterns as well as indirect effects of the dog-owner relationship. The role and weight of such mechanisms in shaping dogs’ attention to owners’ remains to be addressed
Take a picture! The role of visual methods in understanding psychiatric patient's everyday life
No full textBACKGROUND AND AIM: Understanding the patient's experience of mental illness can foster better support for this population and greater partnership with healthcare professionals. This study aims to explore the application of visual methods in the psychiatric field and, in particular, the experience of people suffering from psychotic disorders because it is still an open question that has not been only partially empirically examined. METHODS: This qualitative study was conducted using two visual methods (auto-photography and photo-elicitation) associated with the narrative that emerged from an unstructured interview, in a clinical setting of adult Mental Health in Italy, between October 2019 and February 2020. A total of 5 patients and 5 corresponding referring healthcare professionals were identified and enrolled. Patients were asked to produce photographs following 4 thematic areas: "Fun", "Time", "Something indispensable", "Place where I feel good". RESULTS: A total of 85 photographs were produced. Visual methods have proved to be a useful technique in qualitative research in the area of adult psychiatry. From the interviews, it emerged that visual methods have allowed psychotic patients to use a new language to be able to communicate their emotions. CONCLUSIONS: The healthcare professionals involved also confirm the potential of this tool which, when combined with the traditional interview, is able to deepen the patient's knowledge by overcoming the verbal barriers that often make it difficult to reconstruct the individual experience of illness
Alternatives to use from wastes treated through the extraction of metals and manufacturing of MDP
No full textA madeira em seu estado natural está susceptÃvel ao ataque de organismos xilófagos e por isso são necessários tratamentos que melhorem o seu desempenho e ampliem as possiblidades de uso desse material, bem como os locais em que pode ser aplicado. Os preservativos de madeira mais utilizados são os de origem quÃmica e, dentre eles o Arseniato de Cobre Cromatado (CCA) tem vasta utilização no Brasil e no mundo. Esse preservativo atende aos requisitos de atuar como inseticida, fungicida e fixador, porém, com relação as questões ambientais como um todo, esse produto traz certa insegurança, por ser composto de metais pesados que são prejudiciais ao ambiente, saúde humana e animal, dificultando as formas de descarte e reciclagem quando sai de serviço. Com isso, o objetivo do presente trabalho foi avaliar a possibilidade de reciclagem da madeira tratada com CCA retirada de serviço, a partir da fabricação de painéis aglomerados e aplicar técnicas que promovam a remoção dos metais da madeira a fim de ampliar e facilitar as formas de destinação final. Para isso, foram coletados 4 postes (Eucalyptus spp.) tratados com CCA e já retirados de serviço, seccionando, de cada poste, dois toretes com 1 m de comprimento, sendo um acima e outro abaixo da zona de afloramento. Foram realizadas análises de massa especÃfica da madeira, quantificação dos metais do CCA do material, e confeccionados painéis aglomerados de média densidade com misturas de Pinus caribaea entre os tratamentos. Também, testes de eletrorremoção em diferentes condições, em escala de bancada e extração ácida foram aplicados no material. Os resultados indicaram que a técnica de eletrorremoção foi eficaz, removendo taxas próximas a 100% dos metais de cobre, cromo e arsênio do material tratado, bem como, a extração ácida, sem a aplicação do campo elétrico, trouxe resultados satisfatórios. Com relação aos dados obtidos sobre a qualidade dos painéis MDP, os tratamentos envolvendo madeira tratada com CCA com misturas de Pinus caribaea apresentaram excelentes resultados de propriedades fÃsicas e mecânicas. Contudo, para os produtos envolvendo o material tratado e submetido à extração ácida, os painéis não alcançaram resultados aceitáveis, onde o envolvimento de ácidos no processo de extração ácida pode ter afetado na colagem das partÃculas dos painéis, reduzindo a resistência mecânica dos mesmos. De maneira geral, a técnica de eletrorremoção e extração ácida é viável, removendo os metais presentes no material, ampliando as formas e locais de uso desse resÃduo, e recomenda-se mais estudos acerca da aplicação da metodologia em maior escala. O mesmo é indicado para os produtos gerados dos painéis MDP, onde incentiva-se o uso da madeira tratada na condição de resÃduo na fabricação dos mesmos, sendo uma alternativa tecnicamente viável e ambientalmente sustentável.Wood in its natural state is susceptible to the attack of xylophagous organisms and for this reason treatments are necessary to improve its performance and expand the possibilities of using this material, as well as the places where it can be applied. The most used wood preservatives are of chemical origin and, among them, the Chromated Copper Arsenate (CCA) is widely used in Brazil and in the world. This preservative meets the requirements as insecticide, fungicide, and fixative; however, in relation to environmental issues, this product brings some insecurity, due to the heavy metals that are harmful to the environment, human and animal health. This characteristic difficult to discard and recycle the treated lumber when out of service. Thus, the objective of this work was to evaluate the possibility of recycling wood treated with CCA removed from service, as manufacturing particleboard as well applying techniques to remove the metals from wood in order to expand and facilitate the forms of final disposal. For this purpose, 4 posts (Eucalyptus spp.) treated with CCA and already removed from service were collected, removing from each post two pieces 1 m long, one above and one below the outcropping zone. Analyses of the wood specific weigth, quantification of the CCA metals in the material were performed, and medium density particleboard were made with mixtures of Pinus caribaea among the treatments. Also, electroremoval tests under different conditions, on bench scale and acid extraction were applied on the material. The results indicated that the electroremoval technique was effective, removing rates close to 100% of copper, chromium, and arsenic metals from the treated material, and acid extraction, without the application of the electric field, brought satisfactory results. Regarding the MDP quality, the treatments involving wood treated with CCA andh Pinus caribaea mixtures showed excellent results in terms of physical and mechanical properties. However, for the products involving the treated material previously submitted to acid extraction, the panels did not achieve acceptable results. Probably the acids action in the acid extraction process affected the particles, reducing the panel mechanical resistance. In general, the electroremoval and acid extraction technique are viable, removing the metals present in the material, expanding the ways and places of use of this residue, and further studies are recommended about the application of the methodology on a larger scale. The same is indicated for the MDP, where the addiction of treated wood residue in the manufacture is encouraged, being a technically feasible and environmentally sustainable alternative
Seasonal variation in the leaf-litter frog community (Amphibia: Anura) from an Atlantic Forest Area in the Salto Morato Natural Reserve, southern Brazil
No full textIn this study we provide the first data regarding community parameters of leaf-litter anurans inhabiting a forest floor in the state of Paraná, southern Brazil, including information on community species richness, composition, specific density and biomass. Our study was conducted at Salto Morato Natural Reserve using forty plots of 4 x 4 m for each one of the four seasons (winter, spring, summer and autumn), totaling 2.560 m² of forest floor sampled. We sampled a total of 96 frogs inhabiting the forest floor, belonging to seven species: Brachycephalus hermogenesi (Giaretta & Sawaya, 1998), Ischnocnema guentheri (Steindachner, 1864), Haddadus binotatus (Spix, 1824), Leptodactylus gr. marmoratus, Physalaemus spiniger (Miranda-Ribeiro, 1926), Proceratophrys boiei (Wied-Neuwied, 1824), and Rhinella abei (Baldissera, Caramaschi & Haddad, 2004). The overall frog density in the forest floor was 3.73 ind/100m², with I. guentheri (1.37 ind/100 m²) being the most common species and R. abei (0.19 ind/100 m²), the rarest. The estimated overall frog mass in the community was 3.29 g. The abundance, richness and density varied consistently among the four seasons sampled, with the highest values occurring in the spring and summer seasons
Realocação de nitrogênio e de biomassa para os grãos, em trigo submetido a inoculação de Azospirillum Reallocation of nitrogen and biomass to the seeds in wheat inoculated with Azospirillum bacteria
No full textEstudou-se, em condições de campo, o efeito de inoculante turfoso em pó contendo bactérias do gênero Azospirillum no rendimento de grãos e na remobilização de N e de biomassa para os grãos de trigo (Triticum aestivum L.), cultivar Embrapa 16. Usaram-se como inoculantes, a estirpe de Azospirillum brasilense 245 e o isolado 10 de Azospirillum lipoferum. Em cada tratamento de inoculação, e também sem inoculação, aplicaram-se diferentes doses de N em diferentes estádios de desenvolvimento das plantas, distribuÃdos em blocos ao acaso com parcelas subdivididas. Na antese e na maturação fisiológica, avaliaram-se o acúmulo de massa seca e N total nas diferentes partes da planta. Na colheita, além do rendimento de grãos, avaliaram-se também o Ãndice de colheita para biomassa e para N, os principais componentes do rendimento e o teor de N total de grãos. Os resultados ainda preliminares evidenciaram que, mesmo não havendo efeito da inoculação no rendimento de grãos, houve um melhor alocamento de N e de biomassa para os grãos, resultando em maior massa de mil grãos e em menor quantidade de N restante na palha das plantas na maturação fisiológica. Esses efeitos resultaram de um menor número de espigas m-2, provavelmente devido à morte de afilhos, fator que determinou maior disponibilidade de N e de biomassa à s espigas e grãos restantes.The effect of inoculating wheat (Triticum aestivum L.) seeds, cultivar Embrapa 16, with powder peat inoculant containing Azospirillum bacteria on yield and remobilization of nitrogen and biomass was studied under field conditions. The strain of Azospirillum brasilense 245 and the isolate 10 of Azospirillum lipoferum were used as inoculants. Different rates of nitrogen were applied at varying stages of plant growth for each inoculated and non-inoculated treatment, distributed in blocks at random with split plots. The accumulation of dry matter and total nitrogen in plant parts was evaluated at anthesis and physiological maturity stages. Harvest index for biomass and N, main yield components, and total N content in the seeds, in addition to yield, were also evaluated at harvest. The preliminary results showed that, even without inoculation effect on yield, there was a better allocation of nitrogen and biomass to the seeds, resulting in heavier seeds, with a lower amount of nitrogen remaining in the straw at physiological maturity. Such effects resulted from a lower number of spikes m-2, probably due to the death of tillers, determining a greater availability of N and biomass to the remaining spikes and seeds
Realocação de nitrogênio e de biomassa para os grãos, em trigo submetido a inoculação de Azospirillum
No full textThe effect of inoculating wheat (Triticum aestivum L.) seeds, cultivar Embrapa 16, with powder peat inoculant containing Azospirillum bacteria on yield and remobilization of nitrogen and biomass was studied under field conditions. The strain of Azospirillum brasilense 245 and the isolate 10 of Azospirillum lipoferum were used as inoculants. Different rates of nitrogen were applied at varying stages of plant growth for each inoculated and non-inoculated treatment, distributed in blocks at random with split plots. The accumulation of dry matter and total nitrogen in plant parts was evaluated at anthesis and physiological maturity stages. Harvest index for biomass and N, main yield components, and total N content in the seeds, in addition to yield, were also evaluated at harvest. The preliminary results showed that, even without inoculation effect on yield, there was a better allocation of nitrogen and biomass to the seeds, resulting in heavier seeds, with a lower amount of nitrogen remaining in the straw at physiological maturity. Such effects resulted from a lower number of spikes m-2, probably due to the death of tillers, determining a greater availability of N and biomass to the remaining spikes and seeds.Estudou-se, em condições de campo, o efeito de inoculante turfoso em pó contendo bactérias do gênero Azospirillum no rendimento de grãos e na remobilização de N e de biomassa para os grãos de trigo (Triticum aestivum L.), cultivar Embrapa 16. Usaram-se como inoculantes, a estirpe de Azospirillum brasilense 245 e o isolado 10 de Azospirillum lipoferum. Em cada tratamento de inoculação, e também sem inoculação, aplicaram-se diferentes doses de N em diferentes estádios de desenvolvimento das plantas, distribuÃdos em blocos ao acaso com parcelas subdivididas. Na antese e na maturação fisiológica, avaliaram-se o acúmulo de massa seca e N total nas diferentes partes da planta. Na colheita, além do rendimento de grãos, avaliaram-se também o Ãndice de colheita para biomassa e para N, os principais componentes do rendimento e o teor de N total de grãos. Os resultados ainda preliminares evidenciaram que, mesmo não havendo efeito da inoculação no rendimento de grãos, houve um melhor alocamento de N e de biomassa para os grãos, resultando em maior massa de mil grãos e em menor quantidade de N restante na palha das plantas na maturação fisiológica. Esses efeitos resultaram de um menor número de espigas m-2, provavelmente devido à morte de afilhos, fator que determinou maior disponibilidade de N e de biomassa à s espigas e grãos restantes
