Análise comparativa de um sistema de refrigeração solar

Nesta dissertação são comparadas duas tecnologias de refrigeração. Uma tecnolo-gia é um sistema que usa a energia elétrica para fazer funcionar um ciclo de com-pressão de vapor, sistema comum em instalações de refrigeração. A outra solução é um sistema de absorção, em que a energia necessária para o funcionamento do sistema é energia térmica obtida através de coletores solares térmicos. Estas tecnologias são estudadas e comparadas para a refrigeração de um arma-zém de produtos agrícolas à temperatura constante de 5ºC para a região de Alque-va, região onde estão a ser desenvolvidos projetos hortofrutícolas a que estão as-sociadas necessidades de preservação dos produtos que envolvem refrigeração e em que a acessibilidade à rede elétrica é reduzida. É mostrado que a tecnologia do sistema de absorção com os coletores se apresenta a médio prazo mais vantajosa em termos económicos e ambientais; Abstract: Comparative analysis of a solar refrigeration system In this dissertation two refrigeration technologies are compared when used for the same objective. One is a technology using the electric energy to operate a vapour compression cycle, commonly used in refrigerated installations. The alternative technology is an absorption system driven by thermal energy, provided by solar thermal collectors. Both technologies are studied and compared for the refrigeration of an agricultural products warehouse at a constant temperature of 5ºC in the Alqueva region, where horticultural projects are being developed with associated needs of preservation of the products involving refrigeration, and where accessibility to the electrical grid is reduced. In the referred conditions it was shown that the absorption technology with collec-tors in the medium term surpasses the usual compression system, both from eco-nomic and environmental viewpoints.

"Portuguese Observatory of Taeniasis and Cysticercosis": A "One Health" example for epidemiological surveillance of one neglected disease in a European country

Cysticercosis results from the ingestion Taenia solium eggs directly by faecal-oral route or contaminated food or water. Human tapeworm carriers who have become infected after ingesting pork meat contaminated with cysticerci release these eggs. Cysticercosis occurs after tapeworm eggs are ingested by an intermediate host (pig or human) and then hatch, migrate, and lodge in the host's tissues, where they develop onto larval cysticerci. When they lodged in the central nervous system of humans, results in the disease condition called Neurocysticercosis (NCC), with a heterogeneous manifestations depending of the locations of cysts, number, size and their stage of evolution (1). Consequently the prognostic ranges from asymptomatic to situations leading to death in 2% to 9.8%. of cases (7) In swine’s there are few studies, but recent works have proved that animals, for the same reasons, also have neurological abnormalities, expressed by seizures, stereotypic walk in circles, chewing motions with foamy salivation included tonic muscle contractions followed by a sudden diminution in all muscle tone leading to collapse (2). Conventional domestic wastewater treatment processes may not be totally effective in inactivating parasites eggs from Taenia solium, allowing some contamination of soils and agricultural products (11). In Portugal there are some evidence of aggregation of human cysticercosis cases in specific regions, bases in ecological design studies (6). There are few information about human tapeworm carriers and social and economic factors associated with them. Success in knowledge and consequently in lowering transmission is limited by the complex network of biological and social factors that maintain the spread. Effective control of mostly zoonosis require One Health approach, after a real knowledge and transparency in the information provided by the institutions responsible for both animal and human health, allowing sustained interventions targeted at the transmission cycle's crucial nodes. In general, the model used to control, reflects a rural reality, where pigs are raised freely, poor sanitation conditions and incipient sanitary inspection. In cysticercosis, pigs are obligate intermediate hosts and so considered as first targets for control and used as sentinels to monitor environmental T. solium contamination (3). Usually environmental contamination with Taenia spp. eggs is a key issue in most of studies with landscape factors influencing presence of Taenia spp. antigens in both pigs and humans (5). Soil-related factors as well as socio-economic and behavioural factors are associated with the emergence of significant clustering human cysticercosis (4,5). However scarce studies has been produced in urban environmental and in developed countries with the finality to characterize the spatial pattern. There are still few data available regarding its prevalence and spatial distribution; Transmission patterns are likely to exhibit correlations as housing conditions, water supply, basic sanitation, schooling and birthplace of the individual or relatives, more than pigs rearing free, soil conditions (9). As a matter of fact, tapeworm carriers from endemic zones can auto-infect or transmit infection to other people or arrive already suffering NCC (as a result of travelling to or being a citizen from an endemic cysticercosis country) to a free cysticercosis country. Transmission is fecal-oral; this includes transmission through person-to-person contact, through autoinfection, or through contaminated food This has been happening in different continents as North America (5.4–18% been autochthonous), Europe and Australia (7). Recently, case reports of NCC have also emerged from Muslim countries. (10). Actually, different papers relate an epidemic situation in Spain and Portugal (7, 8). However the kind of study done does not authorize such conclusion. There are no evidence that infections were acquired in Portugal and there are not characterized the mode of transmission. Papers with these kind of information will be allow to have economic consequences resulted from artificial trade barriers with serious consequences for pig producers and pig meat trade. We need transparency in information’s that allow provide the basis to support the development and targeting of future effective control programmes (and prove we need that). So, to have a real picture of the disease, it is necessary integrate data from human, animal and environmental factors surrounding human and pig cases to characterize the pattern of the transmission. The design needs to be able to capture unexpected, and not common outcomes (routine data). We need to think “One Health” to get a genuine image of the situation.

First report on Meloidogyne chitwoodi hatching inhibition activity of essential oils and essential oils fractions

The Columbia root-knot nematode (CRKN), Meloidogyne chitwoodi, is an EPPO A2 type quarantine pest since 1998. This nematode causes severe damage in economically important crops such as potato and tomato, making agricultural products unacceptable for the fresh market and food processing. Commonly used nematicidal synthetic chemicals are often environmentally unsafe. Essential oils (EOs) may constitute safer alternatives against RKN. EOs, isolated from 56 plant samples, were tested against CRKN hatching, in direct contact bioassays. Some of the most successful EOs were fractionated and the hydrocarbon molecules (HM) and oxygen-containing molecules (OCM) fractions tested separately. 24 EOs displayed very strong hatching inhibitions (≥90 %) at 2 µL mL−1 and were further tested at lower concentrations. Dysphaniaambrosioides, Filipendula ulmaria, Ruta graveolens, Satureja montana and Thymbra capitata EOs revealed the lowest EC50 values (<0.15 µL mL−1). The main compounds of these EOs, namely 2-undecanone, ascaridol, carvacrol, isoascaridol, methyl salicylate, p-cymene and/or γ-terpinene, were putatively considered responsible for CRKN hatching inhibition. S. montana and T. capitata OCM fractions showed hatching inhibitions higher than HM fractions. The comparison of EO and corresponding fractions EC50 values suggests interactions between OCM and HM fractions against CRKN hatching. These species EOs showed to be potential environmentally friendly CRKN hatching inhibitors; nonetheless, bioactivity should be considered globally, since its HM and OCM fractions may contribute, diversely, to the full anti-hatching activity.