2,144 research outputs found
Transmitted Energy as a Basic System Resource
Energy is a basic resource in digital transmission links.
Physically, radio channels correspond to passive circuits and
most of the transmitted energy is lost in the channel. Two
alternative approaches are used for performance measurements
in terms of energy. Either the average transmitted or received
energy per bit is used, both usually normalized by the receiver
noise spectral density. This leads to the average transmitted or
received signal-to-noise ratio (SNR) per bit, respectively.
However, the transmitted energy is the basic system resource.
The average energy gain of a channel depends on the transmitted
signal. For convenience, the transmitted SNR referred to the
receiver is defined to be the product of the transmitted SNR and
the representative energy gain, which is defined as the average
energy gain of a signal that is uniformly distributed in all
dimensions: time, frequency and space. An explicit relationship
between the transmitted and received SNR’s using the covariance
concept is derived. Limitations of the use of different SNR
definitions are summarized
Effect of different mowing regimes on butterflies and diurnal moths on road verges
In northern and central Europe road verges offer alternative habitats for declining plant and invertebrate species of semi-natural grasslands. The quality of road verges as habitats depends on several factors, of which the mowing regime is one of the easiest to modify. In this study we compared the Lepidoptera communities on road verges that underwent three different mowing regimes regarding the timing and intensity of mowing; mowing in mid-summer, mowing in late summer, and partial mowing (a narrow strip next to the road). A total of 12,174 individuals and 107 species of Lepidoptera were recorded. The mid-summer mown verges had lower species richness and abundance of butterflies and lower species richness and diversity of diurnal moths compared to the late summer and partially mown verges. By delaying the annual mowing until late summer or promoting mosaic-like mowing regimes, such as partial mowing, the quality of road verges as habitats for butterflies and diurnal moths can be improved
The student-produced electronic portfolio in craft education
The authors studied primary school students’ experiences of using an electronic portfolio in their craft education over four years. A stimulated recall interview was applied to collect user experiences and qualitative content analysis to analyse the collected data. The results indicate that the electronic portfolio was experienced as a multipurpose tool to support learning. It makes the learning process visible and in that way helps focus on and improves the quality of learning. © ISLS.Peer reviewe
Efecto de los distintos regímenes de siega de los márgenes de las carreteras sobre las polillas diurnas y las mariposas
In northern and central Europe road verges offer alternative habitats for declining plant and invertebrate species of semi–natural grasslands. The quality of road verges as habitats depends on several factors, of which the mowing regime is one of the easiest to modify. In this study we compared the Lepidoptera communities
on road verges that underwent three different mowing regimes regarding the timing and intensity of mowing; mowing in mid–summer, mowing in late summer, and partial mowing (a narrow strip next to the road). A total of 12,174 individuals and 107 species of Lepidoptera were recorded. The mid–summer mown verges had lower species richness and abundance of butterflies and lower species richness and diversity of diurnal moths compared to the late summer and partially mown verges. By delaying the annual mowing until late summer or promoting mosaic–like mowing regimes, such as partial mowing, the quality of road verges as habitats for butterflies and diurnal moths can be improved.En Europa central y septentrional los márgenes de las carreteras constituyen hábitats alternativos para especies de invertebrados y plantas de los prados semi–naturales cuyas poblaciones se están reduciendo. La calidad de los márgenes de las carreteras como hábitats depende de diversos factores, de los cuales el régimen de siega es de los más fáciles de modificar. En este estudio se compararon las comunidades de lepidópteros de los márgenes de las carreteras que sufrieron tres regímenes distintos de siega, según el momento y la intensidad de la siega; siega a mediados del verano, siega a finales de éste, y siega parcial (una estrecha franja próxima a la carretera). Se estudiaron un total de 12.174 individuos y 107 especies de lepidópteros. Los márgenes segados a mediados de verano presentaban una menor riqueza de especies y abundancia de mariposas, y una menor riqueza de especies y diversidad de polillas diurnas, en comparación con los márgenes segados a finales de verano o segados parcialmente. Retrasando la siega anual hasta finales del verano, o promoviendo regímenes de siega en forma de mosaico, tales como la siega parcial, podría mejorarse la calidad de los márgenes de las carreteras como hábitats para las mariposas y las polillas diurnas
Suomalaiset lääkärit ja Suomen Lääkäriliitto osana hyvinvointivaltiota ja sen terveyspolitiikkaa
Tässä julkaisussa selvitetään Suomen Lääkäriliiton ideoita (makrotaso) ja lääkäreiden (mikrotaso) mielipiteitä hyvinvointivaltiosta ja sen terveyspolitiikasta. Makrotason aineiston muodostavat erilaiset julkiset dokumentit. Aineistot ovat pääosin vuosilta 1970–2007. Dokumentteja analysoidaan sekä määrällisen että laadullisen sisällönanalyysin tai erittelyn keinoin. Mikrotason aineiston muodostaa vuonna 2007 kerätty kyselyaineisto (n = 1 092). Sitä analysoidaan kuvailevin tilastollisin menetelmin ja logistisen regressioanalyysin keinoin. Tulosten perusteella Suomen Lääkäriliitto koki julkisen vallan puuttumisen uhkaksi rakennettaessa universaalia terveydenhuoltojärjestelmää. Uhka kuitenkin väheni julkisen sektorin jatkuvasti laajentuessa. Toisaalta jatkuvana vaatimuksena Lääkäriliiton dokumenteissa esiintyy 1970-luvulta lähtien yksityisen sektorin roolin lisäämisvaateet. 1990-luvun laman jälkeisenä aikana yksityiseen sektoriin liittyvät ideat ovat tulleet yhä selkeämmiksi ja konkreettisemmiksi. Argumenteissaan Lääkäriliitto ei tuo juurikaan esille omia taloudellisia intressejään vaan vetoaa useammin yleiseen hyvään. Kyselyaineistosta tehtyjen analyysien mukaan lääkärit kokevat sosiaaliturvan muuta väestöä useammin liian laajaksi. Lääkärit eivät kuitenkaan halua erityisen voimakkaasti markkinoistaa terveydenhuoltoa, jopa verrattaessa muuhun väestöön. Parhaiten lääkäreiden mielipiteitä sosiaaliturvasta ja terveydenhuoltojärjestelmästä selittävät poliittinen orientaatio ja työskentelysektori. Nuorten lääkäreiden mielipiteet sosiaaliturvasta ja terveydenhuoltojärjestelmästä eivät ole erityisen radikaaleja. Lopuksi tutkimuksessa verrattiin mikro- ja makrotasoa keskenään. Tulosten perusteella Suomen Lääkäriliitto on selvästi radikaalimpi näkemyksissään markkinoistumisesta kuin lääkärit keskimäärin.15,00 euro
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Spatial epidemiological patterns suggest mechanisms of land-sea transmission for Sarcocystis neurona in a coastal marine mammal.
Sarcocystis neurona was recognised as an important cause of mortality in southern sea otters (Enhydra lutris nereis) after an outbreak in April 2004 and has since been detected in many marine mammal species in the Northeast Pacific Ocean. Risk of S. neurona exposure in sea otters is associated with consumption of clams and soft-sediment prey and is temporally associated with runoff events. We examined the spatial distribution of S. neurona exposure risk based on serum antibody testing and assessed risk factors for exposure in animals from California, Washington, British Columbia and Alaska. Significant spatial clustering of seropositive animals was observed in California and Washington, compared with British Columbia and Alaska. Adult males were at greatest risk for exposure to S. neurona, and there were strong associations with terrestrial features (wetlands, cropland, high human housing-unit density). In California, habitats containing soft sediment exhibited greater risk than hard substrate or kelp beds. Consuming a diet rich in clams was also associated with increased exposure risk. These findings suggest a transmission pathway analogous to that described for Toxoplasma gondii, with infectious stages traveling in freshwater runoff and being concentrated in particular locations by marine habitat features, ocean physical processes, and invertebrate bioconcentration
Five-year follow-up of a randomized clinical trial comparing open surgery, foam sclerotherapy and endovenous laser ablation for great saphenous varicose veins
Background: New treatment methods have challenged open surgery as a treatment for great saphenous vein (GSV) insufficiency, the most common being ultrasound-guided foam sclerotherapy (UGFS) and endovenous laser ablation (EVLA). This study evaluated the long-term results of surgery, EVLA and UGFS in the treatment of GSV reflux. Methods: Patients with symptomatic GSV reflux were randomized to undergo either open surgery, EVLA or UGFS. The main outcome measure was the occlusion rate of the GSV at 5years after operation. Results: The study included 196 patients treated during 2008-2010; of these, 166 (847 per cent) participated in the 5-year follow-up. At 5years, the GSV occlusion rate was 96 (95 per cent c.i. 91 to 100) per cent in the open surgery group, 89 (82 to 98) per cent after EVLA and 51 (38 to 64) per cent after UGFS (P Conclusion: UGFS has significantly inferior occlusion rates compared with open surgery or EVLA, and results in additional treatments.Peer reviewe
Extending Existential Feeling Through Sensory Substitution
In current philosophy of mind, there is lively debate over whether emotions, moods, and other affects can extend to comprise elements beyond one’s organismic boundaries. At the same time, there has been growing interest in the nature and significance of so-called existential feelings, which, as the term suggests, are feelings of one’s overall being in the world. In this article, I bring these two strands of investigation together to ask: Can the material underpinnings of existential feelings extend beyond one’s skull and skin? To begin, I introduce and adopt a componential-systemic view of extended affectivity. In doing so, I specify the vehicle externalist criteria for extension employed in my analysis. I then define what existential feelings are and pinpoint several key issues in their potential extension. More specifically, I identify sensorimotor ‘know-how’ as a possibly extending component of existential feeling and posit it as the fulcrum of my argument. Finally, I move on to consider the extension of existential feeling via sensory substitution, especially through so-called Tactile Visual Sensory Substitution (TVSS) devices. Informed by both philosophical and empirical studies, I argue that, under certain conditions, (a) the agent’s implicit sensorimotor processing and a TVSS device can become coupled into a new systemic whole, which in turn (b) reconfigures the material underpinnings of the agent’s pre-intentional world-experience. This, I conclude, counts as a cogent case for extended existential feeling
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