172 research outputs found
Prognostics of vibration induced risk to operators of agricultural machinery
Frequent use of vibrating hand-held tools and operation of machinery can result in various chronic diseases. Operators of machinery are often afflicted with peripheral and systematic disorders. The statistical data collected over several decades clearly indicate the lack of operator’s safety from exposure to vibrations. The causes and impacts of vibration effects on humans are reviewed in annual reports by health and safety experts in many countries. One of the most common occupational diseases that has been frequently reported is the musculoskeletal disorder due to extended exposure to mechanical vibrations. The influence of vibrations during time period τ can be described by vibro-energy load aτ2·τ. If this load value over a specified time period does not exceed the permissible level a2·T0, it will not induce negative effects on human health. This approach was used in the present study for the prediction of hands and whole body vibration effects on operators of various vibration inducing machinery. Agricultural operators were selected as test subjects, since agricultural tractors and other mobile machinery emit high levels of vibration. Vibration data were obtained from statistical reports developed in the time period from 1988 to 2008. It was found that majority of agricultural machinery does not guarantee proper vibration safety. Thus organizational prevention methods should be developed and implemented. Reduction of vibrations by various technical methods and/or reduction of vibration exposure could be costly, but they are needed in order to provide effective solutions in reducing vibration risk to operators
Effect of logging wounds on diameter growth of beech (Fagus orientalis Lipsky) trees following selection cutting in Caspian forests of Iran
Background Logging damage to residual trees during selection cutting may lead to serious economic losses in terms of both timber quality and diameter growth reduction. In this study, we investigated the effect of logging operations on residual tree damage and the consequence of injuries on diameter growth in an uneven-aged mixed forest dominated by beech (Fagus orientalis Lipsky)
Large-area microfocal spectroscopic ellipsometry mapping of thickness and electronic properties of epitaxial graphene on Si- and C-face of 3C-SiC(111)
Factors associated with disease evolution in Greek patients with inflammatory bowel disease
BACKGROUND: The majority of Crohn's disease patients with B1 phenotype at diagnosis (i.e. non-stricturing non-penetrating disease) will develop over time a stricturing or a penetrating pattern. Conflicting data exist on the rate of proximal disease extension in ulcerative colitis patients with proctitis or left-sided colitis at diagnosis. We aimed to study disease evolution in Crohn's disease B1 patients and ulcerative colitis patients with proctitis and left-sided colitis at diagnosis. METHODS: 116 Crohn's disease and 256 ulcerative colitis patients were followed-up for at least 5 years after diagnosis. Crohn's disease patients were classified according to the Vienna criteria. Data were analysed actuarially. RESULTS: B1 phenotype accounted for 68.9% of Crohn's disease patients at diagnosis. The cumulative probability of change in disease behaviour in B1 patients was 43.6% at 10 years after diagnosis. Active smoking (Hazard Ratio: 3.01) and non-colonic disease (non-L2) (Hazard Ratio: 3.01) were associated with behavioural change in B1 patients. Proctitis and left-sided colitis accounted for 24.2%, and 48.4% of ulcerative colitis patients at diagnosis. The 10 year cumulative probability of proximal disease extension in patients with proctitis and left-sided colitis was 36.8%, and 17.1%, respectively (p: 0.003). Among proctitis patients, proximal extension was more common in non-smokers (Hazard Ratio: 4.39). CONCLUSION: Classification of Crohn's disease patients in B1 phenotype should be considered as temporary. Smoking and non-colonic disease are risk factors for behavioural change in B1 Crohn's disease patients. Proximal extension is more common in ulcerative colitis patients with proctitis than in those with left-sided colitis. Among proctitis patients, proximal extension is more common in non-smokers
Impact of Abandoned Land on Environmental Protection, Landscape and Economic Benefit in Lithuania
Abstract. Human economic activity is defined as an anthropogenic process that has a negative impact on natural envi-ronment. The urbanisation and agricultural development influence the environment mostly. In order to receive economic benefit to the above-mentioned activities, the landscape is changed, the soil is affected and pollutants are released into the environment. In the light of the fact that the identified processes and problems caused by them are global, the variety of international directives are designed to minimise the impact of anthropogenic activities on the environment. The territory of the Republic of Lithuania has a considerable amount of areas, where the economic activity is sus-pended, i.e. the land is abandoned. This is due to a variety of social, natural and economic reasons. This process can be perceived as opposite to the anthropogenic activity, however it is important to examine how it affects the environment, landscape or economic needs. These processes are relevant on the local and international level, therefore, the scientific results of this article may be useful for the professionals in various areas and further research. The research investigates the territory of abandoned agricultural land, which is to be urbanised in the future. Land cadastre data, spatial planning documents are analysed, a questionnaire-based survey is conducted, and the actual inspec-tion in the area is carried out. The research results identify the causes for non-use of the land, and the impact of no eco-nomic activity on the environment, the landscape and the economic performance. To reach the set objectives, the data analysis, synthesis, induction methods have been used
Stochastic De-repression of Rhodopsins in Single Photoreceptors of the Fly Retina
The photoreceptors of the Drosophila compound eye are a classical model for studying cell fate specification. Photoreceptors (PRs) are organized in bundles of eight cells with two major types – inner PRs involved in color vision and outer PRs involved in motion detection. In wild type flies, most PRs express a single type of Rhodopsin (Rh): inner PRs express either Rh3, Rh4, Rh5 or Rh6 and outer PRs express Rh1. In outer PRs, the K50 homeodomain protein Dve is a key repressor that acts to ensure exclusive Rh expression. Loss of Dve results in de-repression of Rhodopsins in outer PRs, and leads to a wide distribution of expression levels. To quantify these effects, we introduce an automated image analysis method to measure Rhodopsin levels at the single cell level in 3D confocal stacks. Our sensitive methodology reveals cell-specific differences in Rhodopsin distributions among the outer PRs, observed over a developmental time course. We show that Rhodopsin distributions are consistent with a two-state model of gene expression, in which cells can be in either high or basal states of Rhodopsin production. Our model identifies a significant role of post-transcriptional regulation in establishing the two distinct states. The timescale for interconversion between basal and high states is shown to be on the order of days. Our results indicate that even in the absence of Dve, the Rhodopsin regulatory network can maintain highly stable states. We propose that the role of Dve in outer PRs is to buffer against rare fluctuations in this network
Gene Expression Profile of Neuronal Progenitor Cells Derived from hESCs: Activation of Chromosome 11p15.5 and Comparison to Human Dopaminergic Neurons
BACKGROUND: We initiated differentiation of human embryonic stem cells (hESCs) into dopamine neurons, obtained a purified population of neuronal precursor cells by cell sorting, and determined patterns of gene transcription.
METHODOLOGY: Dopaminergic differentiation of hESCs was initiated by culturing hESCs with a feeder layer of PA6 cells. Differentiating cells were then sorted to obtain a pure population of PSA-NCAM-expressing neuronal precursors, which were then analyzed for gene expression using Massive Parallel Signature Sequencing (MPSS). Individual genes as well as regions of the genome which were activated were determined.
PRINCIPAL FINDINGS: A number of genes known to be involved in the specification of dopaminergic neurons, including MSX1, CDKN1C, Pitx1 and Pitx2, as well as several novel genes not previously associated with dopaminergic differentiation, were expressed. Notably, we found that a specific region of the genome located on chromosome 11p15.5 was highly activated. This region contains several genes which have previously been associated with the function of dopaminergic neurons, including the gene for tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine biosynthesis, IGF2, and CDKN1C, which cooperates with Nurr1 in directing the differentiation of dopaminergic neurons. Other genes in this region not previously recognized as being involved in the functions of dopaminergic neurons were also activated, including H19, TSSC4, and HBG2. IGF2 and CDKN1C were also found to be highly expressed in mature human TH-positive dopamine neurons isolated from human brain samples by laser capture.
CONCLUSIONS: The present data suggest that the H19-IGF2 imprinting region on chromosome 11p15.5 is involved in the process through which undifferentiated cells are specified to become neuronal precursors and/or dopaminergic neurons
Farm diversification decision-making stages
Ūkio diversifikacijos sprendimo priėmimo modeliavimas yra aktuali mokslinė problema, nes ūkio diversifikacijos sprendimo realizavimo tyrimai nėra dažni. Straipsnio tikslas – pateikti pagrindinius ūkio diversifikacijos sprendimo priėmimo etapus. Teoriniam ūkio diversifikacijos sprendimo priėmimo modeliui patikrinti naudota ekspertų apklausa. Buvo apklausta 14 ekspertų. Nustatyta, kad ūkio diversifikacijos tikslų susiejimas su identifikuotų galimybių išorinėje aplinkoje ar ūkininko ūkyje išnaudojimu, sukuria ūkio vystymo prielaidas. Identifikuoti nauji ūkio diversifikacijos sprendimo alternatyvų formulavimo būdai. Patvirtiti šie ūkio diversifikacijos sprendimo alternatyvų vertinimo kriterijai: sprendimo išorinės įgyvendinamumo galimybės, vidinės įgyvendinamumo galimybės, sinerginiai ryšiai, rizikingumas. Mokymasis turėtų tapti permanentiniu procesu, jis aktualus visuose ūkio diversifikacijos sprendimo priėmimo etapuose.That the farmer's decision to diversify the farm will achieve its objectives, it must be properly designed. Modeling of farm diversification decision–making is a scientific problem, because tests of the farm diversification decision realization are not common in the scientific literature. It is achieved article aim – identified the main farm’s diversification decision–making stages. The expert survey was used to check the theoretical diversification farmer’s decision–making model. 14 experts were interviewed. The study found that the farm diversification objectives connection with identified opportunities in external environment or with farm exploitation creates preconditions for farm development. Expert interviews helped identify new formulation methods of farm diversification solution alternatives. The farm diversification decision alternatives are important to assess according to following criteria: decision outside feasibility, internal feasibility, synergies, riskiness. Learning should become a permanent process
Role of TLR1, TLR2 and TLR6 in the modulation of intestinal inflammation and Candida albicans elimination
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