361 research outputs found

    Ground-source heat pumps and underground thermal energy storage: energy for the future

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    We need energy for space heating—but in most cases not where or when energy sources are available. Energy storage, which helps match energy supply and demand, has been practised for centuries, also in Norway. Energy storage systems will increase the potential of utilising renewable energy sources such as geothermal energy, solar heat and waste heat. The most frequently-used storage technology for heat and ‘coolth’ is Underground Thermal Energy Storage (UTES). The ground has proved to be an ideal medium for storing heat and cold in large quantities and over several seasons or years. UTES systems in the Nordic countries are mostly used in combination with Ground-Source Heat Pumps (GSHP). Several different UTES systems have been developed and tested. Two types of system, Aquifer (ATES) and borehole (BTES) storage, have had a general commercial breakthrough in the last decades in the Nordic countries. Today, about 15,000 GSHP systems exist in Norway extracting about 1.5 TWh heat from the ground. About 280 of the Norwegian GSHP installations are medium- to large-scale systems (> 50 kW) for commercial/public buildings and for multi-family dwellings. The two largest closed-loop GSHP systems in Europe, using boreholes as ground heat exchangers, are located in Norway

    ACCELERATED LEARNING BERBANTUAN SOFTWARE MAPLE SEBAGAI UPAYA MENINGKATKAN KEMAMPUAN KOMUNIKASI MATEMATIS DAN MINAT BELAJAR SISWA SMA

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    Penelitian ini dilatarbelakangi oleh pentingnya kemampuan komunikasi matematis dan minat belajar. Namun kenyataan di lapangan menunjukkan bahwa kemampuan komunikasi matematisdan minat belajarsiswa masih rendah. Agar permasalahan tersebut dapat diatasi, diperlukan sebuah model pembelajaran yang dapatmeningkatkankemampuan komunikasi matematis dan minat belajarsiswa.Olehkarenaitu, dipilih modelAccelerated Learning Berbantuan Software Maple. Penelitian ini bertujuan untuk menelaahpeningkatan kemampuan komunikasi matematis dan minat belajarsiswa, danmenelaahhubunganantara kemampuan komunikasi dan minat belajar.Penelitianinimerupakanpenelitiankuasieksperimendenganpretest-postest control group design. Populasi pada penelitian ini adalah seluruh siswa kelas X pada salah satu SMA Negeri di Kota Purwokerto. Sampel terdiri dari dua kelas yang dipilih secara purposive sampling.Instrumen yang digunakan berupa tes kemampuan komunikasi matematis dan angket minat belajar, lembar observasi, serta pedoman wawancara. Analisis data dilakukan secara kuantitatif.Analisis data tersebutmenggunakanMann-Whitney U Testdan uji asosiasi Chi Square. Berdasarkan analisis data, ditemukan bahwa: (1)pencapaian kemampuan komunikasi matematis siswa yang memperoleh Accelerated LearningBerbantuanSoftware Maplelebih baik daripada siswa yang memperoleh pembelajaran biasa;(2) peningkatan kemampuan komunikasi matematis siswa yang memperoleh Accelerated LearningBerbantuanSoftware Maplelebih baik daripada siswa yang memperoleh pembelajaran biasa, (3) pencapaian kemampuan minat belajar siswa yang memperoleh Accelerated LearningBerbantuanSoftware Maplelebih baik daripada siswa yang memperoleh pembelajaran biasa; (4) peningkatan kemampuan minat belajar siswa yang memperoleh Accelerated LearningBerbantuanSoftware Maplelebih baik daripada siswa yang memperoleh pembelajaran biasa; dan(5) terdapat asosiasi antara kemampuan komunikasi dan minat belajarsiswadengan kategori rendah. ---------- This research was motivated by the importance of mathematical communication learning interest of students. Mathematical communication ability and learning interest of students is still low. In order that this problemscan be solved, alearning modelthatcan enhancemathematical communication and learning interest ofstudents is required.In this research, Maple-Assisted Accelerated Learning was selected. This studyaims to analyzetheenhancement of mathematical communication learning interest of students, and to analyzetheassociationbetween mathematical communication ability andlearning interest of students. This research was aquasi-experimentalwithpretest-posttest control group design. The population was students at tenth gradein one of senior high schools in Purwokerto, Central Java. The sample consisted oftwoclasses which wasselected bypurposivesampling. This research used fourinstruments: testof mathematicalcommunication ability, learning interestquestionnaire, observation sheets, and interview guide.Data analyzed was done quantitatively. The data were analyzed by usingMann-Whitney U TestandChi Squaren test. Based on the data analyze, it is found that: (1) the achievement of mathematical communication ability of students who receivedthe Maple-Assisted Accelerated Learning is betterthan the achievement of students who receivedconventionallearning;(2) The enhancement of mathematical communication ability of students who receivedthe Maple-Assisted Accelerated Learning is betterthan the enhancement of students who receivedconventionallearning; (3)the achievement oflearning interestability of students who receivedthe Maple-Assisted Accelerated Learning is betterthan the achievement of students who receivedconventionallearning; (4)the enhancement oflearning interestof students who receivedthe Maple-Assisted Accelerated Learning is betterthan the enhancement of students who receivedconventionallearning; and(5) there is anassociation between students’ mathematical communication ability and learning interest of student

    Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

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    Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures

    Evaluering av utprøving av digital hjemmeoppfølging: Delrapport II

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    Med støtte fra Helsedirektoratet prøver seks lokale prosjekter i kommunal regi ut digital hjemmeoppfølging av personer med kronisk sykdom. Utprøvingen gjennomføres i perioden 2018-2021 som en del av Nasjonalt velferdsteknologiprogram. Formålet med utprøvingen er å få tilstrekkelig kunnskap om digital hjemmeoppfølging til å gi nasjonale anbefalinger om implementering av tiltaket. Utprøvingen evalueres av forskere fra Universitetet i Oslo, Oslo Economics og Nasjonal senter for distriksmedisin. I denne delrapporten beskriver vi erfaringer med og effekter av digital hjemmeoppfølging til og med høsten 2020

    Cold Physiology: Postprandial Blood Flow Dynamics and Metabolism in the Antarctic Fish Pagothenia borchgrevinki

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    Previous studies on metabolic responses to feeding (i.e. the specific dynamic action, SDA) in Antarctic fishes living at temperatures below zero have reported long-lasting increases and small peak responses. We therefore hypothesized that the postprandial hyperemia also would be limited in the Antarctic fish Pagothenia borchgrevinki. The proportion of cardiac output directed to the splanchnic circulation in unfed fish was 18%, which is similar to temperate fish species. Contrary to our prediction, however, gastrointestinal blood flow had increased by 88% at twenty four hours after feeding due to a significant increase in cardiac output and a significant decrease in gastrointestinal vascular resistance. While gastric evacuation time appeared to be longer than in comparable temperate species, digestion had clearly commenced twenty four hours after feeding as judged by a reduction in mass of the administered feed. Even so, oxygen consumption did not increase suggesting an unusually slowly developing SDA. Adrenaline and angiotensin II was injected into unfed fish to investigate neuro-humoral control mechanisms of gastrointestinal blood flow. Both agonists increased gastrointestinal vascular resistance and arterial blood pressure, while systemic vascular resistance was largely unaffected. The hypertension was mainly due to increased cardiac output revealing that the heart and the gastrointestinal vasculature, but not the somatic vasculature, are important targets for these agonists. It is suggested that the apparently reduced SDA in P. borchgrevinki is due to a depressant effect of the low temperature on protein assimilation processes occurring outside of the gastrointestinal tract, while the gastrointestinal blood flow responses to feeding and vasoactive substances resemble those previously observed in temperate species

    Long-term trends in survival of a declining population: the case of the little owl (Athene noctua) in the Netherlands

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    The little owl (Athene noctua) has declined significantly in many parts of Europe, including the Netherlands. To understand the demographic mechanisms underlying their decline, we analysed all available Dutch little owl ringing data. The data set spanned 35 years, and included more than 24,000 ringed owls, allowing detailed estimation of survival rates through multi-state capture–recapture modelling taking dispersal into account. We investigated geographical and temporal variation in age-specific survival rates and linked annual survival estimates to population growth rate in corresponding years, as well as to environmental covariates. The best model for estimating survival assumed time effects on both juvenile and adult survival rates, with average annual survival estimated at 0.258 (SE = 0.047) and 0.753 (SE = 0.019), respectively. Juvenile survival rates decreased with time whereas adult survival rates fluctuated regularly among years, low survival occurring about every 4 years. Years when the population declined were associated with low juvenile survival. More than 60% of the variation in juvenile survival was explained by the increase in road traffic intensity or in average temperature in spring, but these correlations rather reflect a gradual decrease in juvenile survival coinciding with long-term global change than direct causal effects. Surprisingly, vole dynamics did not explain the cyclic dynamics of adult survival rate. Instead, dry and cold years led to low adult survival rates. Low juvenile survival rates, that limit recruitment of first-year breeders, and the regular occurrence of years with poor adult survival, were the most important determinants of the population decline of the little owl

    Long-term trends in survival of a declining population: the case of the little owl (Athene noctua) in the Netherlands

    Get PDF
    The little owl (Athene noctua) has declined significantly in many parts of Europe, including the Netherlands. To understand the demographic mechanisms underlying their decline, we analysed all available Dutch little owl ringing data. The data set spanned 35 years, and included more than 24,000 ringed owls, allowing detailed estimation of survival rates through multi-state capture–recapture modelling taking dispersal into account. We investigated geographical and temporal variation in age-specific survival rates and linked annual survival estimates to population growth rate in corresponding years, as well as to environmental covariates. The best model for estimating survival assumed time effects on both juvenile and adult survival rates, with average annual survival estimated at 0.258 (SE = 0.047) and 0.753 (SE = 0.019), respectively. Juvenile survival rates decreased with time whereas adult survival rates fluctuated regularly among years, low survival occurring about every 4 years. Years when the population declined were associated with low juvenile survival. More than 60% of the variation in juvenile survival was explained by the increase in road traffic intensity or in average temperature in spring, but these correlations rather reflect a gradual decrease in juvenile survival coinciding with long-term global change than direct causal effects. Surprisingly, vole dynamics did not explain the cyclic dynamics of adult survival rate. Instead, dry and cold years led to low adult survival rates. Low juvenile survival rates, that limit recruitment of first-year breeders, and the regular occurrence of years with poor adult survival, were the most important determinants of the population decline of the little owl
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