Spectral analysis of ground magnetic data in Magadi area, Southern Kenya rift

The area surrounding Lake Magadi in the southern Kenya rift is characterized by hot springs that issue from fractures distributed along the shores of the lake. Presence of earthquake swarms that cluster in northern margin of Lake Magadi strongly indicate magmatic activity in the area. This study was done as a follow-up to investigate depth to the heat source possibly causing high seismic activity and high heat flow in the area. A ground magnetic survey was conducted to investigate geothermal potential of the area and a magnetic anomaly contour map prepared. Spectral analysis involving determining power spectrum was applied to magnetic data along selected profiles cutting through discerned anomalies. Spectral analysis results suggest that the Curie-point isotherm depth under Magadi ranges from 5.20 km to 8.30 km. Estimated vertical temperature gradients along the profiles ranges from 111.53°C/km to 69.92°C/km. The hightemperature gradients and relatively shallow Curie point depths indicates high heat flow which suggests presence of a hot magmatic intrusion

An investigation of the structure beneath Magadi area in southern Kenya rift using gravimetric data

Magadi area is located in the southern part of the Kenyan rift, an activecontinental rift that is part of the East African Rift system. Local seismic activity monitored previously around Lake Magadi revealed an earthquake cluster caused by swarm activity in the rift centre at shallow depths, which was probably triggered by magma movements. There was need for a follow-up to locate any body at depth with sufficient density contrast that may represent magmatic intrusions. Gravity measurements were carried out in 58 established stations and data from 52 other stations merged from existing coverage of previous measurements. Necessary corrections were applied to the gravity data and a Bouguer contour map prepared. Euler deconvolution technique was used to image depth to the causative bodies along selected profiles on the Bouguer anomaly map. Two  dimensional gravity forward models of the subsurface structure were generated by using Euler depth solutions in the start models. Among others, a unique body of density of 3.20 gcm-3 was modelled on the northern region near little Magadi at a depth of approximately 0.4 km. The location of the body coincides with the area where earthquake swarm occurs. Such a body of high density contrasts may be caused by mafic intrusions into the crust. Discontinuities in Euler solution cluster along the profiles indicated buried faults in the volcanic rift infill. The high seismicity may hence be associated to magma intrusions.Key words: Gravity, Bouguer anomaly, Euler Deconvolution, Keny

Identification of Ceruloplasmin as a Gene that Affects Susceptibility to Glomerulonephritis Through Macrophage Function

Crescentic glomerulonephritis (Crgn) is a complex disorder where macrophage activity and infiltration are significant effector causes. In previous linkage studies using the uniquely susceptible Wistar Kyoto (WKY) rat strain, we have identified multiple crescentic glomerulonephritis QTL (Crgn) and positionally cloned genes underlying Crgn1 and Crgn2, which accounted for 40% of total variance in glomerular inflammation. Here, we have generated a backcross (BC) population (n = 166) where Crgn1 and Crgn2 were genetically fixed and found significant linkage to glomerular crescents on chromosome 2 (Crgn8, LOD = 3.8). Fine mapping analysis by integration with genome-wide expression QTLs (eQTLs) from the same BC population identified ceruloplasmin (Cp) as a positional eQTL in macrophages but not in serum. Liquid chromatography-tandem mass spectrometry confirmed Cp as a protein QTL in rat macrophages. WKY macrophages overexpress Cp and its downregulation by RNA interference decreases markers of glomerular proinflammatory macrophage activation. Similarly, short incubation with Cp results in a strain-dependent macrophage polarization in the rat. These results suggest that genetically determined Cp levels can alter susceptibility to Crgn through macrophage function and propose a new role for Cp in early macrophage activation

Estimation of the Optimal Statistical Quality Control Sampling Time Intervals Using a Residual Risk Measure

Background: An open problem in clinical chemistry is the estimation of the optimal sampling time intervals for the application of statistical quality control (QC) procedures that are based on the measurement of control materials. This is a probabilistic risk assessment problem that requires reliability analysis of the analytical system, and the estimation of the risk caused by the measurement error. Methodology/Principal Findings: Assuming that the states of the analytical system are the reliability state, the maintenance state, the critical-failure modes and their combinations, we can define risk functions based on the mean time of the states, their measurement error and the medically acceptable measurement error. Consequently, a residual risk measure rr can be defined for each sampling time interval. The rr depends on the state probability vectors of the analytical system, the state transition probability matrices before and after each application of the QC procedure and the state mean time matrices. As optimal sampling time intervals can be defined those minimizing a QC related cost measure while the rr is acceptable. I developed an algorithm that estimates the rr for any QC sampling time interval of a QC procedure applied to analytical systems with an arbitrary number of critical-failure modes, assuming any failure time and measurement error probability density function for each mode. Furthermore, given the acceptable rr, it can estimate the optimal QC sampling time intervals

Site-specific prolapse surgery. I. Reliability and durability of native tissue paravaginal repair

Introduction and hypothesis: This study aims to compare native tissue abdominal and vaginal paravaginal repair, and to investigate whether surgical outcome was independent of operative route. Methods: Retrospective comparison of 111 displacement cysto-urethrocoeles, repaired between 1997 and 2007. Treatment was by surgeon assignment, 52 women having abdominal (APVR) and 59 vaginal paravaginal repairs. Main outcome measures were same-site prolapse recurrence, time to failure and surgical complications. Initial reliability was evaluated by chi-square test, 10-year durability by Kaplan-Meier survival analysis and Cox proportional hazards model. Results: When examined in the Cox proportional hazards model, anatomic results of APVR were more durable than a mechanically analogous transvaginal operation done [95% CI=1.029-2.708 (p value=0.038)]. Kaplan-Meier curves plateaued within 38 months. Symptom resolution was broadly equivalent. Surgical complication rate was 3.6%. Conclusions: Site-specific re-suture of torn native tissue has genuine curative potential. Most of the long-term success was attributable to site-specific repair, rather than nonspecific scar formation.9 page(s

Apraxia and motor dysfunction in corticobasal syndrome

Background: Corticobasal syndrome (CBS) is characterized by multifaceted motor system dysfunction and cognitive disturbance; distinctive clinical features include limb apraxia and visuospatial dysfunction. Transcranial magnetic stimulation (TMS) has been used to study motor system dysfunction in CBS, but the relationship of TMS parameters to clinical features has not been studied. The present study explored several hypotheses; firstly, that limb apraxia may be partly due to visuospatial impairment in CBS. Secondly, that motor system dysfunction can be demonstrated in CBS, using threshold-tracking TMS, and is linked to limb apraxia. Finally, that atrophy of the primary motor cortex, studied using voxel-based morphometry analysis (VBM), is associated with motor system dysfunction and limb apraxia in CBS.   Methods: Imitation of meaningful and meaningless hand gestures was graded to assess limb apraxia, while cognitive performance was assessed using the Addenbrooke's Cognitive Examination - Revised (ACE-R), with particular emphasis placed on the visuospatial subtask. Patients underwent TMS, to assess cortical function, and VBM.   Results: In total, 17 patients with CBS (7 male, 10 female; mean age 64.4+/2 6.6 years) were studied and compared to 17 matched control subjects. Of the CBS patients, 23.5% had a relatively inexcitable motor cortex, with evidence of cortical dysfunction in the remaining 76.5% patients. Reduced resting motor threshold, and visuospatial performance, correlated with limb apraxia. Patients with a resting motor threshold <50% performed significantly worse on the visuospatial sub-task of the ACE-R than other CBS patients. Cortical function correlated with atrophy of the primary and pre-motor cortices, and the thalamus, while apraxia correlated with atrophy of the pre-motor and parietal cortices.   Conclusions: Cortical dysfunction appears to underlie the core clinical features of CBS, and is associated with atrophy of the primary motor and pre-motor cortices, as well as the thalamus, while apraxia correlates with pre-motor and parietal atrophy

The vertebrate muscle Z-disc: sarcomere anchor for structure and signalling

The Z-disc, appearing as a fine dense line forming sarcomere boundaries in striated muscles, when studied in detail reveals crosslinked filament arrays that transmit tension and house myriads of proteins with diverse functions. At the Z-disc the barbed ends of the antiparallel actin filaments from adjoining sarcomeres interdigitate and are crosslinked primarily by layers of α-actinin. The Z-disc is therefore the site of polarity reversal of the actin filaments, as needed to interact with the bipolar myosin filaments in successive sarcomeres. The layers of α-actinin determine the Z-disc width: fast fibres have narrow (~30–50 nm) Z-discs and slow and cardiac fibres have wide (~100 nm) Z-discs. Comprehensive reviews on the roles of the numerous proteins located at the Z-disc in signalling and disease have been published; the aim here is different, namely to review the advances in structural aspects of the Z-disc

High-Resolution Genotyping via Whole Genome Hybridizations to Microarrays Containing Long Oligonucleotide Probes

To date, microarray-based genotyping of large, complex plant genomes has been complicated by the need to perform genome complexity reduction to obtain sufficiently strong hybridization signals. Genome complexity reduction techniques are, however, tedious and can introduce unwanted variables into genotyping assays. Here, we report a microarray-based genotyping technology for complex genomes (such as the 2.3 GB maize genome) that does not require genome complexity reduction prior to hybridization. Approximately 200,000 long oligonucleotide probes were identified as being polymorphic between the inbred parents of a mapping population and used to genotype two recombinant inbred lines. While multiple hybridization replicates provided ∼97% accuracy, even a single replicate provided ∼95% accuracy. Genotyping accuracy was further increased to >99% by utilizing information from adjacent probes. This microarray-based method provides a simple, high-density genotyping approach for large, complex genomes