247 research outputs found
Orientational effects on the amplitude and phase of polarimeter signals in double resonance atomic magnetometry
Double resonance optically pumped magnetometry can be used to measure static magnetic fields with high sensitivity by detecting a resonant atomic spin response to a small oscillating field perturbation. Determination of the resonant frequency yields a scalar measurement of static field (B_0) magnitude. We present calculations and experimental data showing that the on-resonance polarimeter signal of light transmitted through an atomic vapour in arbitrarily oriented may be modelled by considering the evolution of alignment terms in atomic polarisation. We observe that the amplitude and phase of the magnetometer signal are highly dependent upon B_0 orientation, and present precise measurements of the distribution of these parameters over the full 4 pi solid angle
A feed-forward measurement scheme for periodic noise suppression in atomic magnetometry
We present an unshielded, double-resonance magnetometer in which we have implemented a feed-forward measurement scheme in order to suppress periodic magnetic noise arising from, and correlated with, the mains electricity alternating current line. The technique described here uses a single sensor to track ambient periodic noise and feed forward to suppress it in a subsequent measurement. This feed forward technique has shown significant noise suppression of electrical mains-noise features of up to 22 dB under the fundamental peak at 50 Hz, 3 dB at the first harmonic (100 Hz), and 21 dB at the second harmonic (150 Hz). This technique is software based, requires no additional hardware, and is easy to implement in an existing magnetometer
Patient Perspectives of an Intensive Comprehensive Aphasia Program for Stroke Survivors
Introduction: Persons with aphasia (PWA) who participate in intensive comprehensive poststroke language rehabilitation programs make a variety of significant investments. While intensive aphasia programs and intensive comprehensive aphasia programs (ICAPs) are becoming increasingly prevalent across health care settings, patient perspectives of ICAPs have not been explored. The purpose of this qualitative study was to examine patient perspectives about the experience of participating in an ICAP at the University of Montana. The primary research question of this study was: “what is it like to be a PWA in an ICAP?” Methods: Researchers used an interpretive phenomenological approach to conduct nine structured interviews from PWAs who described their lived experiences in the ICAP. All interviews were audiovisually recorded and transcribed from the video recordings. Analysis involved an iterative and collaborative coding process. Transcripts were coded and themes were developed from the PWAs’ shared perspectives. Results: Three primary themes emerged from patient perspectives including: (1) experience with each of the ICAP components is generally positive, (2) we notice the impact of the ICAP on our communication, and (3) relationships with people in the ICAP are important. Discussion: Results support emerging evidence that ICAPs can be a positive experience for PWA due to the perceptible impact on communication improvement and frequent and varied opportunities to interact with others. ICAPs may be a worthwhile investment for PWA, thereby contributing to the cost-benefit utility and implementation feasibility of the service delivery model
Isolation and characterization of the xenopus laevis cdna and genomic homologs of neuropeptide Y
We have isolated Xenopus laevis cDNA and genomic clones encoding the neuropeptide Y (NPY) mRNA and gene using a probe from the human NPY gene. The longest open reading frame in the cDNA encodes a peptide 76% identical to human prepro-NPY and 73% identical to rat prepro-NPY. The putative mature Xenopus NPY (XNPY) peptide is 94% identical to both human and rat peptides. A genomic clone containing 422 base pairs of 5'-flanking sequences and the 5'-end of the mRNA was also isolated. Primer extension analysis was used to map the transcription initiation site of the Xenopus NPY gene. Comparison of the 5 '-flanking sequences of the Xenopus laevis, human, and rat NPY genes resulted in areas of high conservation, including the TATA box and the CT box previously shown to interact with Spl-like proteins. Distribution of the Xenopus NPY message was analyzed by Northern analysis and RNAse protection. XNPY transcripts were not detected in whole developing embryo RNA, but were detected in adult frog brain RNA. We have also conducted preliminary studies of the XNPY promoter, utilizing an XNPY/chloramphenicol acetyl-transferase fusion construct. This study has demonstrated that Xenopus NPY shares a high degree of identity to its human and rat counterparts and that this homology extends to the gene, which contains similar cis-elements positioned near the transcription start site.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31586/1/0000515.pd
Critical analysis of environmental water quality in South Africa Historic and current trends
South Africa is widely recognised as having an admirable water law, and as being a leader in granting a right to water, in terms of quality and quantity, to the environment. However, the water quality of South Afri-can water resources is deteriorating (eg CSIR 2010, DWA 2011a), alt-hough good water quality management structures, strategies, ap-proaches, programmes, instruments, and tools have been developed and implemented nationally. The research reported on here provides a review of changes in water quality management structures, pro-grammes and approaches over the past two decades, and highlights areas where these need updating, completion or revision. As a com-parative illustration of changes in water quality with time, changes in 11 water quality parameters in two river systems (the Crocodile River in Mpumalanga, which is moderately impacted, and the Olifants River, in Mpumalanga and Limpopo, which is severely impacted) are presented
Fetal haemoglobin response to hydroxycarbamide treatment and sar1a promoter polymorphisms in sickle cell anaemia
The hydroxycarbamide (HC)-inducible small guanosine triphosphate (GTP)-binding protein, secretion-associated and RAS-related (SAR) protein has recently been shown to play a pivotal role in HBG induction and erythroid maturation by causing cell apoptosis and G1/S-phase arrest. Our preliminary analysis indicated that HC inducibility is transcriptionally regulated by elements within the SAR1A promoter. This study aimed to assess whether polymorphisms in the SAR1A promoter are associated with differences Hb F levels or HC therapeutic responses among sickle cell disease (SCD) patients. We studied 386 individuals with SCD comprised of 269 adults treated with or without HC and 117 newborns with SCD identified from a newborn screening program. Three previously unknown single nucleotide polymorphisms (SNPs) in the upstream 5′UTR (−809 C>T, −502 G>T and −385 C>A) were significantly associated with the fetal haemoglobin (HbF) response in Hb SS patients treated with HC (P < 0·05). In addition, four SNPs (rs2310991, −809 C>T, −385 C>A and rs4282891) were significantly associated with the change in absolute HbF after 2 years of treatment with HC. These data suggest that variation within SAR1A regulatory elements might contribute to inter-individual differences in regulation of HbF expression and patient responses to HC in SCD
Benchmarking a Decision Support System for Aquatic Toxicity Testing
This book was written for the catchment management forum (CMF) in the Upper Komati Forum (UKF), and they share their experience in order to help other CMFs understand the damage coal mining does to our water resources. This booklet should be used with How to think and act in ways that make Adaptive IWRM practi-cally possible and How to establish and run a Catchment Management Forum
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