Theory and applications of delta-sigma analogue-to-digital converters without negative feedback

Analog-to-digital converters play a crucial role in modern audio and communication design. Conventional Nyquist converters are suitable only for medium resolutions and require analog components that are precise and highly immune to noise and interference. In contrast, oversampling converters can achieve high resolutions (>20bits) and can be implemented using straightforward, high-tolerance analog components. In conventional oversampled modulators, negative feedback is applied in order to control the dynamic behavior of a system and to realize the attenuation of the quantization noise in the signal band due to noise shaping. However, feedback can also introduce undesirable effects such as limit cycles, jitter problems in continuous-time topologies, and infinite impulse responses. Additionally, it increases the system complexity due to extra circuit components such as nonlinear multi-bit digital-to-analog converters in the feedback path. Moreover, in certain applications such as wireless, biomedical sensory, or microphone implementations feedback cannot be applied. As a result, the main goal of this thesis is to develop sigma-delta data converters without feedback. Various new delta-sigma analog-to-digital converter topologies are explored their mathematical models are presented. Simulations are carried out to validate these models and to show performance results. Specifically, two topologies, a first-order and a second-order oscillator-based delta-sigma modulator without feedback are described in detail. They both can be implemented utilizing VCOs and standard digital gates, thus requiring only few components. As proof of concept, two digital microphones based on these delta-sigma converters without feedback were implemented and experimental results are given. These results show adequate performance and provide a new approach of measuring

Intimacy in Marriage: A Comparison Between Married Men with Children and Married Men Without Children

This investigation explored the differences in perceptions of levels of intimacy in their marriage between married men with children and married men without children. Participants completed the Intimacy Scale (IS). Levels of intimacy were compared between both groups using a two-tailed independent T-test. The results showed that married men with children showed significantly lower levels of intimacy than married men without children. This study will review definitions of intimacy, marital satisfaction, the development of intimacy, how to improve on intimacy, how to experience intimacy within marriage, and how intimacy is related to the transition to parenthood

Spirituality and Depression in Parents with Children in Oncology or Hematology Treatment

The psychological burden of cancer treatment affects not only child patients but also their parents. There is extensive literature on the positive influence of spirituality on the cancer patient. But there is a gap in the literature on the potential healing influence of spirituality on the parent of the cancer or hematology patient. The purpose of this study was to examine the relationship between spirituality and parents\u27 levels of depression and anxiety during their child\u27s hematological or oncology treatment. Using the transtheoretical model of change, a purposive sample of 48 parents of children undergoing cancer or hematology treatment completed a demographic form and the Daily Spiritual Experience Scale (DSES), which was used to divide participants into two groups, spiritual and nonspiritual, based on their median scores. Participants then completed the Beck Depression Inventory (BDI) and the Beck Anxiety Inventory (BAI), which were used as indices of psychological resiliency. These data were analyzed using independent samples t tests and ANOVA to determine if scores on the DSES predicted a difference between groups on both the BDI and the BAI. No significant effects were found. In order to clearly identify the role spirituality plays in mediating resiliency for coping with a life-threatening illness, more precise operational definitions and measures for the construct of psychological resiliency are needed. Implications for positive social change include a better understanding of the role spirituality plays in improved psychological resilience in times of medical crisis. Implementing such programs will lead to social change in the manner in which we counsel and approach parents facing this crisis

CHROMOGRANIN A DETECTION IN SALIVA OF TYPE 2 DIABETES PATIENTS

Chromogranin A is present in secretion granules of nerve, endocrine and immune cells and is a precursor of several peptides with antibacterial and antifungal properties at micromolar concentrations.Our aim in this prospective, double blind study, was to determine the expression of chromogranin A and its peptides at protein level in saliva of type 2 diabetic patients and thereby to obtain a new non-invasive diagnostic means for the future.Saliva was taken from 30 type 2 diabetic patients and 30 healthy individuals at the same time interval in the morning without any oral stimuli. Circadianic periodics in protein productions have been avoided. The presence of chromogranin A and its derived peptides was determined in whole saliva, after centrifugation at 40C for 12 min at 14 000 rpm, by SDS-PAGE electrophoresis and Immunoblotting (Western Blot). To ensure same protein concentrations Bradford protein quantification assay has been performed before.For the first time, we have determined an overexpression of chromogranin A in saliva of diabetic patients in 100% of the individuals.Chromogranin A, a circulating biomarker for epithelial tumours, is also overexpressed in saliva of type 2 diabetic patients. To confirm our results, more studies with a large amount of patients is necessary

Nutrient mineralization patterns in shelf waters of the Western Iberian upwelling

24 páginas, 10 figuras, 2 tablasA set of hydrographicdata collectedduring severalcruisesto theNWIberian upwelling systemhas been used to assess the patterns of nutrient mineralizationover the shelf. Mineralized nutrient ratios (N/P and N/Si)in the lowerwatercohrmnare clearlybelowthe ratios characteristicof freshly upwelled oceanic waters. Nitrogen mineralization, in comparison to phosphorus mineralization, is incomplete,in agreementwith phosphate’sfaster regenerationrate and the low residence time of water, which precludes complete mineralization. Silicate shows the highest enrichmentas a consequenceof the selectiveconcentrationof particulate biogenicsilica in the near bottom waters. Diffusionof nutrients mineralizedin the sedimentsseemsto representan important contribution.TheIowestmineralizationof the surveyedarea is foundto the north of CapeFinisterre, especiallywith regard to silicate.To the South, the Rias Baixas(four large embayments)return as reducingparticulate organicmatter (POM)a smallfraction of the upwellednutrientsimportedfrom the shelf. However,the out-flowingfreshwatercontributesto stratificationof coastal waters, which favoursPOMproduction,accumulationand sedimentation.In addition,highlevelsofnewdissolved organic matter (DOM) in the outflowcan also enhanceprimary productionin shelfsurface waters. Finally, highest mineralization was found to the south of the River Miiio, where there are no embayments and the shelf is wider. Mineralization tends to: (1) increase the potential primary productionof thisecosystembyupto 50%,(nitrogenIimitation)orup to 80%(siliconlimitation);(2) favour the developmentof phytoplanktonassemblagesdominatedbydiatoms(Sienrichmentdouble that ofN and P); and (3)bufferthe largespatial and temporaldifferencesintroducedbythe advected nutrientsSupport for this work came from EU projects contract No. MAST-CT90-0017and MAS2- CT93-006Peer reviewe

Head of State of Exception

During the escalation of the “German Autumn” in 1977 the Federal German government resorted to a specific form of crisis management that had been described as an undeclared state of exception. It was Federal chancellor Helmut Schmidt in the first place who oversaw the anti-terrorist measures in the situation room where the executive branch ruled for six weeks beyond any parliamentary control. This article examines the role that Helmut Schmidt had played for the creation of a “subjective state of exception” (Julius Hatschek) and how this could be seen as stemming from Schmidt’s earlier experiences and handling of crisis situations dating back to the 1960s. In this regard it has to be asked with Giorgio Agamben, if in the West German case, the state of exception had become the rule