<p>Ämnet idrott och hälsa lyfts ofta fram som en viktig komponent för att utveckla en hälsosam</p><p>livsstil. Fysisk aktivitet framhålls av forskare som den viktigaste friskfaktorn. Vid den senaste</p><p>utvärderingen av ämnet idrott och hälsa visade det sig att 16 procent av eleverna inte tyckte</p><p>ämnet var intressant och ett par procent av eleverna deltar aldrig i undervisningen i idrott och</p><p>hälsa. Studiens syfte har varit att undersöka vilka bevekelsegrunder elever i år 7-9 har för att</p><p>inte delta i undervisningen i ämnet idrott och hälsa. Såväl de grunder som eleverna framför till</p><p>sina lärare som de som eleverna inte framför har undersökts. Andra frågeställningar har varit:</p><p>vilka förändringar eleverna önskar för att delta i undervisningen samt hur elevernas skäl att</p><p>inte delta påverkas av den rådande samhällsdiskursen om allt fler inaktiva och/eller</p><p>överviktiga barn. Tre intervjuer med totalt fem intervjupersoner har genomförts och</p><p>analyserats med en hermeneutisk ansats. Resultaten visade att de bevekelsegrunder eleverna</p><p>anger för sina lärare inte är de samma som dc verkliga. Eleverna som intervjuats har en</p><p>negativ inställning till ämnet idrott och hälsa. De upplever att de ingenting lär sig och de är</p><p>rädda att göra bort sig och misslyckas. Några tycker inte att de kommer så bra överens med</p><p>läraren och några tycker inte att dc lever upp till de kroppsideal som förmedlas via</p><p>massmedia. Ingen av eleverna duschar i de duschutrymmen som anvisas. De förändringar som</p><p>eleverna efterfrågar är enskilda duschutrymmen, större valmöjligheter samt mer lek och</p><p>mindre traditionella bollsporter.</p>

Until the 1930s, flows of the Colorado River maintained approximately 781,060 hectares of wetlands in its delta. These wetlands provided important feeding and nesting grounds for resident and migratory birds as well as spawning and protection habitat for many fish and other invertebrate species. However, the Delta's wetlands started to disappear as water was used for agricultural and urban uses in the United States and Mexico. The 1944 United States-Mexico water treaty, which allocates 1.8 million m��/year to Mexico, did not define a minimum flow to maintain the Delta's ecosystems. The resulting degraded Delta lead to the perception in the 1980s that the Delta was a dead ecosystem. This study investigates whether this "dead Delta" perception is valid. Its central hypothesis is that regenerated vegetation in riparian and flood plain zones is associated with surplus river flows during the 1990s. A vegetation analysis, using satellite imagery and field methods, shows that native trees have regenerated during the last 20 years, and now account for 23% of vegetation in a 100 km, non-perennial, stretch of river below the United States-Mexico border. A spatial trend analysis using multi-temporal data on percent vegetation cover indicates that there are 6,320 hectares that show a significant increasing trend (p-value<0.05) in vegetation cover, with the Delta's riparian zone having at least 18% of its area showing this trend. The study estimates that once in four years February to April flow of 300 million m�� (at 80-120 m��/s) is sufficient to germinate and establish new cohorts of native trees, and highlights the need for smaller but more periodic flows in order to maintain wetland areas. It is concluded that there is clear evidence of the resilience of the Delta's ecosystems and that the "dead Delta" perception is no longer valid. There exist critical habitat in the Delta that needs to be protected, while there also exist short and long term opportunities to ecologically enhance and expand current habitat. Hydrological and ecological studies are needed to estimate specific water requirements for these areas in order to efficiently target them for immediate and long term conservation actions. / Graduation date: 2003

The precise measurement of a capacitance difference or ratio in a digital form is very important for capacitive sensors, for CMOS process characterization as well as for the realization of precise switched-capacitor data converters, amplifiers and other circuits utilizing ratioed capacitors. This thesis introduces design techniques for on-chip capacitor ratio testing and sensor readout that utilize sigma-delta modulation and integrate the sensor capacitors into the modulator. Several single-ended circuits are introduced, and the correlated-double-sampling (CDS) technique is used in the circuits to reduce the non-ideal effects of opamps. Several simple calibration schemes for clock-feedthrough cancellation are also introduced and discussed. A fully-differential implementation is also described and various common-mode feedback schemes are discussed and analyzed. Simulation and experimental results show that these circuits can provide extremely accurate results even in the presence of non-ideal circuit effects such as finite opamp gain, opamp input offset and noise, and clock-feedthrough effect from the switches. To verify the effectiveness of the circuits and simulations, two prototype chips containing a single-ended realization and a fully-differential one were designed and fabricated in a 1.2 ��m CMOS technology. Two off-chip mica capacitors were used in the test circuits, and the measured results show that very accurate results can be obtained using these circuit techniques even with off-chip noise coupling and large parasitic capacitances. / Graduation date: 1999

Delta-sigma data converters have gained popularity in both analog-to-digital and digital-to-analog converters (ADCs and DACs) due to their simplicity, high linearity and immunity to many analog circuit imperfections. These data converters include features such as oversampling, noise-shaping, and (historically) single-bit quantization. Single-bit converters are preferred for their inherent linearity. This is a feature which multibit converters cannot realize due to the unavoidable phenomenon of element mismatch. Because of this problem, multibit converters have been largely unexplored, and the market has seen few multibit commercial products. Earlier work has shown that multibit DACs constructed with unit elements can be applied in an architecture which shapes the spectrum of the noise caused by element mismatch. The basis of this thesis is the experimental verification of such a DAC. A Xilinx 4005 FPGA is utilized to implement a 3rd-order 4-bit delta-sigma modulator and the mismatch-shaping logic, while a custom IC consisting of 16 individually-controlled differential current sources implements the unit-element DAC. The final DAC achives a Spurious Free Dynamic Range (SFDR) of 96 dB at a sampling rate of 62.5 kHz. / Graduation date: 1997

Ämnet idrott och hälsa lyfts ofta fram som en viktig komponent för att utveckla en hälsosam livsstil. Fysisk aktivitet framhålls av forskare som den viktigaste friskfaktorn. Vid den senaste utvärderingen av ämnet idrott och hälsa visade det sig att 16 procent av eleverna inte tyckte ämnet var intressant och ett par procent av eleverna deltar aldrig i undervisningen i idrott och hälsa. Studiens syfte har varit att undersöka vilka bevekelsegrunder elever i år 7-9 har för att inte delta i undervisningen i ämnet idrott och hälsa. Såväl de grunder som eleverna framför till sina lärare som de som eleverna inte framför har undersökts. Andra frågeställningar har varit: vilka förändringar eleverna önskar för att delta i undervisningen samt hur elevernas skäl att inte delta påverkas av den rådande samhällsdiskursen om allt fler inaktiva och/eller överviktiga barn. Tre intervjuer med totalt fem intervjupersoner har genomförts och analyserats med en hermeneutisk ansats. Resultaten visade att de bevekelsegrunder eleverna anger för sina lärare inte är de samma som de verkliga. Eleverna som intervjuats har en negativ inställning till ämnet idrott och hälsa. De upplever att de ingenting lär sig och de är rädda att göra bort sig och misslyckas. Några tycker inte att de kommer så bra överens med läraren och några tycker inte att de lever upp till de kroppsideal som förmedlas via massmedia. Ingen av eleverna duschar i de duschutrymmen som anvisas. De förändringar som eleverna efterfrågar är enskilda duschutrymmen, större valmöjligheter samt mer lek och mindre traditionella bollsporter.

Ämnet idrott och hälsa lyfts ofta fram som en viktig komponent för att utveckla en hälsosam livsstil. Fysisk aktivitet framhålls av forskare som den viktigaste friskfaktorn. Vid den senaste utvärderingen av ämnet idrott och hälsa visade det sig att 16 procent av eleverna inte tyckte ämnet var intressant och ett par procent av eleverna deltar aldrig i undervisningen i idrott och hälsa. Studiens syfte har varit att undersöka vilka bevekelsegrunder elever i år 7-9 har för att inte delta i undervisningen i ämnet idrott och hälsa. Såväl de grunder som eleverna framför till sina lärare som de som eleverna inte framför har undersökts. Andra frågeställningar har varit: vilka förändringar eleverna önskar för att delta i undervisningen samt hur elevernas skäl att inte delta påverkas av den rådande samhällsdiskursen om allt fler inaktiva och/eller överviktiga barn. Tre intervjuer med totalt fem intervjupersoner har genomförts och analyserats med en hermeneutisk ansats. Resultaten visade att de bevekelsegrunder eleverna anger för sina lärare inte är de samma som dc verkliga. Eleverna som intervjuats har en negativ inställning till ämnet idrott och hälsa. De upplever att de ingenting lär sig och de är rädda att göra bort sig och misslyckas. Några tycker inte att de kommer så bra överens med läraren och några tycker inte att dc lever upp till de kroppsideal som förmedlas via massmedia. Ingen av eleverna duschar i de duschutrymmen som anvisas. De förändringar som eleverna efterfrågar är enskilda duschutrymmen, större valmöjligheter samt mer lek och mindre traditionella bollsporter.

In this thesis, a 14-bit low-power Analog-to-Digital Converter (ADC) is designed for sensor applications. Following on previous work, the ADC is designed to be frequency scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, class AB opamps are used. The design was fabricated in 0.18um CMOS and occupies an area of 0.35mm2. Operating at full-rate as a Delta-Sigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83uW. In incremental mode, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 89dB peak SNDR while operating from 1.67S/s to 1.67kS/s.

In this thesis, a 14-bit low-power Analog-to-Digital Converter (ADC) is designed for sensor applications. Following on previous work, the ADC is designed to be frequency scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, class AB opamps are used. The design was fabricated in 0.18um CMOS and occupies an area of 0.35mm2. Operating at full-rate as a Delta-Sigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83uW. In incremental mode, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 89dB peak SNDR while operating from 1.67S/s to 1.67kS/s.

This thesis combines detailed analyses of living plant communities with paleolimnological methods to develop the use of plant macrofossils as an effective tool to track hydroecological changes in ponds of the Slave River Delta (SRD), N.W.T. Several approaches were used to develop an understanding of the relationships between hydrolimnological conditions, living plant communities, and the composition of sedimentary macrofossil remains across spatial and temporal scales. A spatial survey approach was used to assess the relationships between the composition of plant macrofossil assemblages contained in the surface sediments and the hydrological and limnological conditions of 40 SRD basins that span a broad range of hydrological settings in the delta. Results show that there are strong relationships between the prevailing hydrolimnological conditions in the SRD and the composition of sedimentary macrofossil remains, and subsequently indicator macrofossil taxa were identified to distinguish between sites with high river influence (flood-dominated sites: ostracode shells, Daphnia ephippia, Chara oospores; exchange-dominated sites: Myriophyllum winter-bud scales, Daphnia ephippia) and sites with low river influence (evaporation-dominated: Ceratophyllum leaves, Lemna leaves, Drepanocladus leaves). In light of the strong connection between spring flood events and the hydrolimnological conditions of SRD ponds, and growing concerns that the frequency of spring floods have declined in recent decades, paleolimnological investigations were initiated at a pond (SD2) adjacent to the Slave River to construct a record of flood events in the SRD. Prior to analysis of macrofossil assemblages from sediment cores, a detailed study of the living plant community was conducted at SD2, and results were compared to the distributions of surficial sedimentary plant macrofossil assemblages to assess how representative surficial sediment assemblages are of the living plant community. This study indicates distinct patch-scale (or quadrat-scale)similarity between the living vegetation and sedimentary remains in the central basin, as well as distinct similarity between the living aquatic macrophytes and sedimentary remains at a pond-scale, suggesting there is excellent potential to track changes in the composition and percent cover of aquatic macrophytes in pond sediment cores using plant macrofossil assemblages. Additionally, this study indicates that influence of long-distance transport of macrofossils during the 2005 flood event was minor at this pond, and may not be an important factor affecting paleolimnological reconstructions of plant communities. With contemporary studies as a framework, an ~90-year record of ice-jam flood frequency was reconstructed from a sediment core collected from pond SD2. Multi-proxy analyses indicated decadal-scale oscillations in flood frequency at this site, with at least three multi-year periods of low river influence. Beginning in ~1943, an 18-year period of particularly low river influence and greatly reduced water levels was indicated by abundant macrofossils of Sagittaria cuneata and represents the driest period over the past ~90-years. Similarities between the flood history of SD2 and upstream sites in the Peace-Athabasca Delta suggest that spring discharge generated from headwaters and major contributing rivers plays a key role in the frequency and magnitude of spring flood events of both deltas.

This thesis combines detailed analyses of living plant communities with paleolimnological methods to develop the use of plant macrofossils as an effective tool to track hydroecological changes in ponds of the Slave River Delta (SRD), N.W.T. Several approaches were used to develop an understanding of the relationships between hydrolimnological conditions, living plant communities, and the composition of sedimentary macrofossil remains across spatial and temporal scales. A spatial survey approach was used to assess the relationships between the composition of plant macrofossil assemblages contained in the surface sediments and the hydrological and limnological conditions of 40 SRD basins that span a broad range of hydrological settings in the delta. Results show that there are strong relationships between the prevailing hydrolimnological conditions in the SRD and the composition of sedimentary macrofossil remains, and subsequently indicator macrofossil taxa were identified to distinguish between sites with high river influence (flood-dominated sites: ostracode shells, Daphnia ephippia, Chara oospores; exchange-dominated sites: Myriophyllum winter-bud scales, Daphnia ephippia) and sites with low river influence (evaporation-dominated: Ceratophyllum leaves, Lemna leaves, Drepanocladus leaves). In light of the strong connection between spring flood events and the hydrolimnological conditions of SRD ponds, and growing concerns that the frequency of spring floods have declined in recent decades, paleolimnological investigations were initiated at a pond (SD2) adjacent to the Slave River to construct a record of flood events in the SRD. Prior to analysis of macrofossil assemblages from sediment cores, a detailed study of the living plant community was conducted at SD2, and results were compared to the distributions of surficial sedimentary plant macrofossil assemblages to assess how representative surficial sediment assemblages are of the living plant community. This study indicates distinct patch-scale (or quadrat-scale)similarity between the living vegetation and sedimentary remains in the central basin, as well as distinct similarity between the living aquatic macrophytes and sedimentary remains at a pond-scale, suggesting there is excellent potential to track changes in the composition and percent cover of aquatic macrophytes in pond sediment cores using plant macrofossil assemblages. Additionally, this study indicates that influence of long-distance transport of macrofossils during the 2005 flood event was minor at this pond, and may not be an important factor affecting paleolimnological reconstructions of plant communities. With contemporary studies as a framework, an ~90-year record of ice-jam flood frequency was reconstructed from a sediment core collected from pond SD2. Multi-proxy analyses indicated decadal-scale oscillations in flood frequency at this site, with at least three multi-year periods of low river influence. Beginning in ~1943, an 18-year period of particularly low river influence and greatly reduced water levels was indicated by abundant macrofossils of Sagittaria cuneata and represents the driest period over the past ~90-years. Similarities between the flood history of SD2 and upstream sites in the Peace-Athabasca Delta suggest that spring discharge generated from headwaters and major contributing rivers plays a key role in the frequency and magnitude of spring flood events of both deltas.