Search results for "barrier"

Sedimentological and tectonic context of Paleoproterozoïque Franceville basin (Gabon) : fluid pressure structures, bitumen and uranium mineralization

2016

Metallogenic deposits within paleproterozoic basins depend on generation and migration of fluids. The aim of this study is to provide a better understanding of tectonic, sedimentological and diagenetic setting of the uranium deposits in the Franceville basin and to characterize hydraulic fracturing impact on fluid migration processes in sandstone reservoirs.Tectonic study define the N180-170° transfer faults, associated with Archean tectonic and the N110-120° longitudinal normal faults. These two fault directions split the Franceville basin into small sub-basins. The longitudinal normal faults are associated with footwall anticlines and hanging wall synclines. The uranium deposits of France…

Internal photoemission in solar blind AlGaN Schottky barrier photodiodes

2005

We have analyzed the photoresponse of solar blind AlGaN Schottky barrier photodiodes below the alloy band gap energy, in the 3.5-4.5 eV range, and we show that it is dominated by internal photoemission. The n-type Schottky barrier height is shown to increase linearly with the band gap energy of the AlGaN alloy. The amplitude of the internal photoemission signal is about 20 times smaller than the value given by the Fowler theory based on a free electron model. We explain this result by taking into account the interband transitions and the ballistic transport of photoexcited electrons in the metal. This low value of internal photoemission allows us to achieve a spectral rejection ratio betwee…

Dimensión socio-laboral de las relaciones comerciales trasatlánticas: algunas lecciones del pasado.

2022

En la cumbre UE-EE.UU. del pasado 15 de junio de 2021, la Unión Europea y los Estados Unidos realizaron una declaración conjunta en la que anunciaron una asociación transatlántica renovada para la era posterior a la pandemia. De manera que en el momento en el que se refuerzan las negociaciones comerciales entre la UE y EE.UU. vale la pena analizar hasta dónde se llegó en las negociaciones del Acuerdo Transatlántico sobre Comercio e Inversión en el marco de la OMC, en particular en relación a los aspectos más controvertidos desde la perspectiva social. Lo que incluye un análisis comparado específicamente enfocado al tratamiento del desplazamiento de trabajadores en el AGCS y en la Directiva …

The Role of the Internet in Overcoming Information Barriers: Implications for Exporting SMEs of the East African Community

2012

Small and medium-sized enterprises play a significant role in the East African Community, contributing highly to the national income and employing a significant number of people. Exportation provides a great opportunity for these enterprises to expand their businesses and improve their performance. However, they encounter a number of information- related barriers before and during exportation. Based on literature, this paper identifies these barriers and discusses how the internet could be used to reduce them. Based on the internet, international business and small business literature, the paper provides propositions and develops a model that will be useful for future studies in this area.

Nitric Oxide/Cyclic Guanosine Monophosphate Signaling via Guanylyl Cyclase Isoform 1 Mediates Early Changes in Synaptic Transmission and Brain Edema …

2021

Traumatic brain injury (TBI) often induces structural damage, disruption of the blood-brain barrier (BBB), neurodegeneration, and dysfunctions of surviving neuronal networks. Nitric oxide (NO) signaling has been suggested to affect brain functions after TBI. The NO exhibits most of its biological effects by activation of the primary targets-guanylyl cyclases (NO-GCs), which exists in two isoforms (NO-GC1 and NO-GC2), and the subsequently produced cyclic guanosine monophosphate (cGMP). However, the specific function of the NO-NO-GCs-cGMP pathway in the context of brain injury is not fully understood. To investigate the specific role of the isoform NO-GC1 early after brain injuries, we perfor…

Tribovoltaic Device Based on the W/WO3 Schottky Junction Operating through Hot Carrier Extraction

2021

A Novel 1,4-Dihydropyridine Derivative Improves Spatial Learning and Memory and Modifies Brain Protein Expression in Wild Type and Transgenic APPSweD…

2015

Ca2+ blockers, particularly those capable of crossing the blood-brain barrier (BBB), have been suggested as a possible treatment or disease modifying agents for neurodegenerative disorders, e.g., Alzheimer's disease. The present study investigated the effects of a novel 4-(N-dodecyl) pyridinium group-containing 1,4-dihydropyridine derivative (AP-12) on cognition and synaptic protein expression in the brain. Treatment of AP-12 was investigated in wild type C57BL/6J mice and transgenic Alzheimer's disease model mice (Tg APPSweDI) using behavioral tests and immunohistochemistry, as well as mass spectrometry to assess the blood-brain barrier (BBB) penetration. The data demonstrated the ability …

Cross-icecap spring migration confirmed in a high-Arctic seabird, the Ivory Gull Pagophila eburnea

2021

Seabirds rarely cross major terrestrial barriers during seasonal migration, possibly because they have a limited ability to build up fat stores. For the first time, we tracked two Ivory Gulls with GPS loggers during spring migration from the wintering area in Davis Strait to the breeding colony in north-east Greenland. While one bird migrated in March around the southern tip of Greenland, the other delayed migration until May and crossed the Greenland icecap north of 70°N, covering 1345 km in 29 h. Several aspects of the crossing were noteworthy: the track was remarkably direct, the bird made several stops (totalling 6 h) on the icecap, and the bird increased its flying altitude to nearly 3…

Promoting Mobility in Older People

2013

Out-of-home mobility is necessary for accessing commodities, making use of neighborhood facilities, and participation in meaningful social, cultural, and physical activities. Mobility also promotes healthy aging as it relates to the basic human need of physical movement. Mobility is typically assessed either with standardized performance-based tests or with self-reports of perceived difficulty in carrying out specific mobility tasks. Mobility declines with increasing age, and the most complex and demanding tasks are affected first. Sometimes people cope with declining functional capacity by making changes in their way or frequency of doing these tasks, thus avoiding facing manifest difficul…

Environmental mobility barriers and walking for errands among older people who live alone vs. with others

2013

Background. Walking is the most popular form of physical activity among older people and for community-dwelling older people walking for errands is especially important. The aim of this study is to examine the association between self-reported environmental mobility barriers and amount of walking for errands among older people who live alone compared to those who live with others. Methods. This observational study is based on cross-sectional data on 657 people aged 75–81 living in Jyväskylä, Central Finland. Self-reports of environmental mobility barriers were collected under four categories: Traffic, Terrain, Distances and Entrance. Persons who reported walking for errands ≤ 1.5 km/week or…