Denna uppsats behandlar elever med lågt deltagande i ämnet Idrott och hälsa. Tio elever på två gymnasieskolor har intervjuats om varför de har låg närvaro vid idrottslektionerna. Syftet med arbetet är att undersöka vad i ämnet Idrott och hälsa som gör att vissa elever väljer att inte delta. Fokus ligger på vilka skäl eleverna anger för att inte delta, samt hur dessa elever skulle vilja förändra undervisningen i Idrott och hälsa för att deras deltagande ska öka. Resultatet pekar på att de skäl eleverna anger för läraren inte alltid stämmer överens med de faktiska skäl som eleverna har. Anledningarna till att eleverna inte vill vara med varierar, men i stora drag handlar det om att eleverna tycker att de traditionella föreningsidrotterna och tävlingsmomenten tar för stor plats. När det gäller förändringar så är det mest frekventa att eleverna vill vara mer delaktiga i att forma sin egen undervisning. De vill också se att de traditionella boll- och lagsporterna får stå tillbaka för fler alternativ i undervisningen. Om företrädarna för ämnet Idrott och hälsa i större utsträckning vill nå alla elever bör ämnet förändras. Kanske behöver ämnets popularitet sättas på spel och ämnets fokus flyttas längre bort från den traditionella föreningsidrotten än vad som idag är fallet.

A dual-mode second-order Multirate Multibit Sigma Delta (MM-SD) modulator is implemented in a 90nm digital CMOS process for application in the baseband path of RF receivers. Low power consumption is achieved through a new integrator structure and a dedicated timing scheme along with aggressive capacitor scaling in the second stage of the modulator loop. Fabricated prototype achieves 68.6dB peak Signal-to-Noise and Distortion ratio (SNDR) in the 200 kHz GSM band and requires 1.1mA of total current from a 1.5V supply. This dual-mode design also achieves 42.8dB SNDR in the 1.94 MHz WCDMA band with only 1.9mA of total current consumption.

The thesis proposes a third order continuous-time sigma delta modulator used in GSM. We used a special 1.5bit quantizer, and to use its three different states to reach a differential feedback path. That can improve the resolution of our circuit. Oversampling and noise shaping are two keys of sigma delta modulator. In structure, the continuous-time features can reduce power consumption. The proposed sigma delta modulator uses TSMC 0.35 m CMOS process and its sampling frequency is 10.8MHz, bandwidth is200KHz and oversampling ratio is 32.

This thesis consists of two topics: A 2.45 GHz ZigBee Receiver Frontend design for home energy-saving systems and a Delta-Sigma ADC with constant-gm amplifier for Battery Management Systems (BMS). A 2.45 GHz ZigBee Receiver Frontend for home energy-saving systems is pre-sented in the first part of this thesis. The proposed ZigBee receiver can be used in areas where wireline solutions are hard to be realized. By employing an LNA at the very frontend of the receiver, the gain is simulated to be 17.376 dB at 2.45 GHz. Besides, by using the double-balanced Gilbert mixer with a current bleeding MOS transistor, the NF and the IIP3 of the mixer are only 5.074 dB and -7.234 dB, respectively. To reduce the phase noise of the receiver, a fractional-N frequency synthesizer with a complementary cross-coupled VCO is adopted. The phase noise of the fractional-N frequency synthe-sizer is 137.7 dBc/Hz. The proposed circuit is carried out and measured on silicon using the standard TSMC 0.18 £gm CMOS process. In the second topic, a Delta-Sigma ADC with constant-gm amplifier is presented. The proposed ADC is particularly designed for the voltage detection circuit in BMS. A constant-gm amplifier is also presented to resolve the nonlinearity of the amplifier de-grading the performance of Delta-Sigma modulator, which is the frontend of the Del-ta-Sigma ADC. With the 4 KHz signal bandwidth, 512 KHz sampling frequency, and 128 oversampling rate, it shows a 85.2 dB SNR, and 12-bit resolution. The backend of the ADC is the decimator, which reduces the sampling frequency compliant with the Nyquist rate rule. The decimator is realized by Verilog code and verified by FPGA. By following the mixed-signal flow, the ADC is realized on a single chip using the standard TSMC 0.25 £gm 60V HV CMOS process.

This study analyzed changes in livelihoods before and after tourism development at Khwai, Mababe and Sankoyo villages in the Okavango Delta. Specifically, it analyzed how people interacted with species like giraffe (Giraffa camelopardalis), sable antelope (Hippotragus niger) and thatching grass (Cymbopogon excavatus) before and after tourism development. This analysis was expected to measure the effectiveness of tourism development as a tool to improve livelihoods and conservation. The concept of social capital, sustainable livelihoods framework and the Community- Based Natural Resource Management (CBNRM) paradigm informed the study. Qualitative and quantitative data were gathered through field-based research, using tools of participant observation, semi-structured interviews, and key informant interviews. Results indicate that local customs and institutions at Khwai, Mababe and Sankoyo ensured the conservation of resources in pre-colonial Botswana. However, British colonial rule (1885-1966) affected traditional institutions of resource use hence the beginning of resource decline. The British colonial rule and the first 15-20 years after Botswana’s independence from British rule saw an increase in resource degradation. Results also indicate that since CBNRM began in the 1990s, tourism development has positive and negative effects on rural livelihoods. On the positive side, tourism development in some ways is achieving its goals of improved livelihoods and conservation. Residents’ attitudes towards tourism development and conservation have also become positive compared to a decade ago when these communities were not involved in tourism development. On the negative side, tourism is emerging as the single livelihood option causing either a decline or abandonment of traditional options like hunting and gathering and agricultural production. Reliance on tourism alone as a livelihood option is risky in the event of a global social, economic and political instability especially in countries where most tourists that visit the Okavango originate or in Botswana itself. There is need, therefore, for communities to diversify into domestic tourism and small-scale enterprises. On the overall, tourism development through CBNRM indicates that it is a viable tool to achieve improved livelihoods and conservation in the Okavango Delta.

Feline lipid metabolism is a topic for greater exploration due to this specie?s unique characteristics. Cats express limited Delta 6-desaturase activity necessary for conversion of linoleic acid (LA, 18:2n-6) to arachidonic acid (AA, 20:4n-6). The possibility exists that Gamma-linolenic acid (GLA, 18:3n-6) may serve as a precursor of AA in reproductive tissues especially if coupled with chain elongation and a functionally active Delta 5-desaturase. In addition no research has been conducted regarding feline reproductive Delta 8-desaturase activity as an alternate to the production of AA. To investigate desaturation activities, a group of 26 adult female cats were randomly assigned into 1 of 3 groups based on the diet fed: High Linoleic Acid (HL, n=7), Low Linoleic Acid (LL, n=9), and High Gamma-Linolenic Acid (GLA, n=10).The diets were fed for 300 days prior to ovariohysterectomy at which time EDTA plasma and ovarian, uterine, and subcutaneous adipose tissues were collected. Homogenates of each tissue were prepared and frozen in aliquots at -80 degrees C. Total lipids were extracted from the plasma and tissue homogenates followed by phospholipid (PL) fractionation via thin layer chromatography and fatty acid (FA) analyses by gas chromatography. The Shapiro-Wilks test was used to determine normal distribution of FA data followed by One-Way ANOVA and Tukey multiple comparisons (p<0.05). Plasma PLs were significantly increased in both GLA and dihomo-Gamma-linolenic acid (DGLA, 20:3n-6Delta8,11,14) in the GLA group and statistically increased in 20:2n-6 and 20:3n-6(Delta5,11,14) in the HL group. Uterine tissue homogenates had significantly increased amounts of DGLA and AA, however ovarian tissue showed an increase of only DGLA. Adipose tissue FAs showed significantly high amounts of DGLA in the GLA group. It is concluded that a high GLA diet results in increased AA in uterine, but not ovarian, tissues and thus may supply eicosanoid precursors in support of reproduction. The presence of increased amounts of 20:3n-6(Delta5,11,14) and not AA in the plasma and uterine tissues in the HL group suggests that Delta6-desaturase cannot be induced and that Delta8-desaturase is not active when feeding high dietary LA. Furthermore, the increase in DGLA may provide an adipose storage reservoir for additional conversion under times of metabolic need. These data support the presence of a functionally active Delta5-desaturase in uterine, but not ovarian, tissues. The findings also suggest that increased dietary GLA may be used to meet the AA requirements for reproduction in cats in the absence of an animal based pre-formed source of AA.

Continuous-time filters are critical components in the implementation of large bandwidth, high frequency, and high resolution continuous-time (CT) sigma-delta (ΣΔ) analog-to-digital converters (ADCs). The loop filter defines the noise-transfer function (NTF) and hence the quantization noise-shaping behavior of the ΣΔ modulator, and becomes the most critical performance determining part in ΣΔ ADC. This thesis work presents the design considerations for the loop filter in low-pass CT ΣΔ ADC with 12-bits resolution in 25MHz bandwidth and low power consumption using 0.18μm CMOS technology. Continuous-time filters are more suitable than discrete-time filters due to relaxed amplifier bandwidth requirements for high frequency ΣΔ ADCs. A fifth-order low-pass filter with cut-off frequency of 25 MHz was designed to meet the dynamic range requirement of the ADC. An active RC topology was chosen for the implementation of the loop filter, which can provide high dynamic range required by the ΣΔ ADC. The design of a summing amplifier and a novel method for adjusting the group delay in the fast path provided by a secondary feedback DAC of the ΣΔ ADC are presented in detail. The ADC was fabricated using Jazz 0.18μm CMOS technology. The implementation issues of OTAs with high-linearity and low-noise performance suitable for the broadband ADC applications are also analyzed in this work. Important design equations pertaining to the linearity and noise performance of the Gm-C biquad filters are presented. A Gm-C biquad with 100MHz center frequency and quality factor 10 was designed as a prototype to confirm with the theoretical design equations. Transistor level circuit implementation of all the analog modules was completed in a standard 0.18μm CMOS process.

The emergence of bandwidth-intensive services has created a need for high speed and high resolution data converters. Towards this end, system level design of a continuous-time sigma-delta modulator achieving 11 bits resolution over 100 MHz signal bandwidth by using a feed-forward topology is presented. The system is first built in the Simulink environment in MATLAB. The building blocks in the loop filter are modeled with non-idealities, and specifications for these blocks are obtained by simulations. An operational transconductor amplifier (OTA) with 100 mS transconductance, 70 dB linearity, and 34.2 mW power dissipation is designed to be used in the loop filter. Simulation results indicate that the 5th order loop filter implemented in the feed-forward architecture in transistor level shows lower power consumption, 105 mW, compared to the loop filter implemented by feedback architecture, 152 mW.

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In the first, a time-variant modulus phase lock loop(PLL) model is established. Applying the model, Theorems of fractional-N synthesizers are introduced. We also explain theorems and simulations of Closed-Loop Modulation and Two-Point Delta Sigma Modulation with the model. In the end, a 2.4GHz FHSS transmitter using Two-Point Delta Sigma Modulation which meets Bluetooth specifications is demonstrated.