On the stochastic mechanics of the free relativistic particle

Given a positive energy solution of the Klein-Gordon equation, the motion of the free, spinless, relativistic particle is described in a fixed Lorentz frame by a Markov diffusion process with non-constant diffusion coefficient. Proper time is an increasing stochastic process and we derive a probabilistic generalization of the equation $(d\tau)^2=-\frac{1}{c^2}dX_{\nu}dX_{\nu}$. A random time-change transformation provides the bridge between the $t$ and the $\tau$ domain. In the $\tau$ domain, we obtain an \M^4-valued Markov process with singular and constant diffusion coefficient. The square modulus of the Klein-Gordon solution is an invariant, non integrable density for this Markov process. It satisfies a relativistically covariant continuity equation

Greenhouse watching system using multi-technologies

Traditional agriculture uses empiric methods and is very exposed to meteorological conditions. To increase the agriculture production, greenhouses had appeared to allow crops with higher quality. Greenhouses also permit the study of cause-effect concepts that by them allow building models that improve the crop’s production and quality. Based on this reality, this paper presents a system developed by researchers of two schools of the Instituto Politécnico of Castelo Branco(IPCB) to monitor a greenhouse located in the campus of Escola Superior Agrária (ESA). This proposed system uses several different technologies

Evidence for fungal infection in cerebrospinal fluid and brain tissue from patients with amyotrophic lateral sclerosis

Among neurogenerative diseases, amyotrophic lateral sclerosis (ALS) is a fatal illness characterized by a progressive motor neuron dysfunction in the motor cortex, brainstem and spinal cord. ALS is the most common form of motor neuron disease; yet, to date, the exact etiology of ALS remains unknown. In the present work, we have explored the possibility of fungal infection in cerebrospinal fluid (CSF) and in brain tissue from ALS patients. Fungal antigens, as well as DNA from several fungi, were detected in CSF from ALS patients. Additionally, examination of brain sections from the frontal cortex of ALS patients revealed the existence of immunopositive fungal antigens comprising punctate bodies in the cytoplasm of some neurons. Fungal DNA was also detected in brain tissue using PCR analysis, uncovering the presence of several fungal species. Finally, proteomic analyses of brain tissue demonstrated the occurrence of several fungal peptides. Collectively, our observations provide compelling evidence of fungal infection in the ALS patients analyzed, suggesting that this infection may play a part in the etiology of the disease or may constitute a risk factor for these patientsThe financial support of Fundación ONCE (Organización Nacional de Ciegos Españoles) is acknowledged. We acknowledge an institutional grant to Centro de Biología Molecular “Severo Ochoa” from the Fundación Ramón Arece

Are the seafloors of marine protected areas sinks for marine litter? Composition and spatial distribution in Cabrera National Park

The seafloors of oceans and seas are becoming major sinks for marine litter (ML) at a global scale and especially within the Mediterranean Sea. Within global oceans and seas, Marine Protected Areas (MPAs) have been established to protect and conserve marine habitats and increase marine biodiversity. In this study, extensive coastal shallow scuba diving surveys were conducted in 2019 and 2020 to identify the distribution of ML in the MPA of Cabrera Marine-Terrestrial National Park (Cabrera MPA) in the Balearic Islands. Approximately 900 items weighing 70.1 kg were collected throughout the MPA during the underwater surveys. Glass bottles, including pieces (25–30%) and glass or ceramic fragments >2.5 cm (8–19%) were the most common identified items followed by plastic food containers and plastic bags (~8%). Overall, 75% of the abundance of collected ML was observed during the first year. In terms of the protection status of the different locations, similar abundances of ML were found in public access areas and no-take areas. Additionally, no significant differences were identified according to location indicating that ML on the seafloor was homogeneous within the studied shallow coastal areas. Overall, the results indicate that Cabrera MPA is a hotspot for ML and mitigation actions and measures, such as annual cleaning efforts, can help to prevent and minimize ML accumulation on the seafloor.En prens

Sistema de condicionamento de ar por dessecante sólido com utilização de energia solar ou residual como fonte de calor de regeneração / Air conditioning system by solid desiccant using solar or residual energy as a source of regeneration heat

A eficiência energética em edifícios e residências é hoje objetivo primordial para a política energética a nível nacional e internacional. Apresentam-se, neste artigo, uma revisão de modelos de condicionamento de ar por roda dessecante com utilização de energia solar ou energia residual como fonte de calor de regeneração. Apresenta-se, também, a modelagem físico-matemático do desumidificador dessecante rotativo. Discutem-se as vantagens de utilizar o sistema de ar-condicionado dessecante giratório pois este combina as tecnologias de desumidificação dessecante e resfriamento evaporativo. Além do mais, é livre de CFCs, usa pouca energia térmica que pode ser diversificada (energia solar e/ou calor residual) e controla a umidade e a temperatura separadamente. Trabalhos de pesquisa recentes sugerem que novos materiais dessecantes e suas configurações possuem um potencial significativo para melhorar o desempenho e a confiabilidade do processo, reduzindo o custo e o tamanho do sistema de desumidificação e ar condicionado com desumidificadores rotativos, aumentando assim a sua competitividade no mercado

Diversidade de espécies e densidade de ninhos de abelhas sociais sem ferrão (Hymenoptera, Apidae, Meliponinae) em floresta de terra firme na Amazônia Central.

Stingless bees were collected between 1984 and 1990 in continuous forest, forest fragments and cleared areas 90 Km north of Manaus, Amazonas, Brazil. Several methods were employed. a total of 54 species of 21 genera were collected including two undescribed species of Plebeia Schwarz, 1938. The most abundant genera were Trigona Jurine, 1807; Melipona Illiger, 1806; Partamona Schwarz, 1939 and Tetragona Lepeletier, 1825. The most abundant species were Trigona crassipes (Fabricius, 1793) and T. fulviventris Guérin, 1835. Fruit fly traps baited with fragrances for euglossine bees showed to be an useful method for stingless bee collection too. The study area showed a great richness in relation to other regions of the world. However the density of nests found from a 100ha area of continuous forest were low (1 nest/6.67ha). The consequences of deforestation on stingless bees populations and of the decrease of these on the forest conservation are also discussed