Balancing Out the Ends during iPSC Nuclear Reprogramming

In this issue of Cell Stem Cell, Marion et al. (2009) report that efficient production of iPSCs requires active telomerase, which allows the rejuvenation of telomeres to a state similar to that observed in embryonic stem cells, even in iPSCs generated from old donor cells

Modeling of storm water runoff for Kitwe CBD drainage system using SWMM software

The 2007/08 rain season caused urban flash floods in urban districts of Lusaka, Central and Copperbelt Provinces. In the Copperbelt, Kitwe City town the flash flood was assumed to be caused by rapid urbanisation, faulty city drainage network and poor storm-water management. This meant that Local Authority of Kitwe City Council are required to mitigate and prevent the reoccurrence of urban flash flood, but this need assessment to determine the true cause of urban flash floods. In some countries the Storm Water Management Model (SWMM) is widely used for planning, analysing and designing storm water runoff and other drainage system in urban areas. SWM is a dynamic rainfall-runoff simulation model which is used for single event or longterm (continuous) simulation of runoff quantity and quality from urban areas.This research was to model storm-water runoff for Kitwe Central Business District with the size of 0.146km², containing 115 storm-water inlets and 5 storm water outlets with SWMM software. The hydrological assessment for rainfall data and rainfall characteristics, land cover for drainage characteristics and usage of land as well as the hydraulic assessment for conveyance network elements were used.Modelling and simulation was conducted using various situations as obtained on project site and these included completely blocked, partially and open drainage system situations, whereas, perfect condition was used to assess the operation of the software. After simulation, status report indicated that urban flash flood experienced in Kitwe CBD during the 2007/08 rainfall was due to lack of drainage maintenance.Keywords: Urban flash floods, Storm Water Management Model, hydrological assessment, Hydraulic assessment, drainage maintenance and modeling/simulatio

Changes in the North Atlantic Oscillation over the 20th century

The North Atlantic Oscillation explains a large fraction of the climate variability across the North Atlantic from the eastern seaboard of North America across the whole of Europe. Many studies have linked the North Atlantic Oscillation to climate extremes in this region, especially in winter, which has motivated considerable study of this pattern of variability. However, one overlooked feature of how the North Atlantic Oscillation has changed over time is the explained variance of the pattern. Here we show that there has been a considerable increase in the percentage of variability explained by the North Atlantic Oscillation (NAO) over the 20th century from 32 % in 1930 to 53 % by the end of the 20th century. Whether this change is due to natural variability, a forced response to climate change, or some combination remains unclear. However, we found no evidence for a forced response from an ensemble of 50 Coupled Model Intercomparison Project Phase 6 (CMIP6) models. These models did all show substantial internal variability in the strength of the North Atlantic Oscillation, but it was biased towards being too high compared to the reanalysis and with too little variation over time. Since there is a direct connection between the North Atlantic Oscillation and climate extremes over the region, this has direct consequences for both the long-term projection and near-term prediction of changes to climate extremes in the region.</p

Online bayesian inference in some time-frequency representations of non-stationary processes

The use of Bayesian inference in the inference of time-frequency representations has, thus far, been limited to offline analysis of signals, using a smoothing spline based model of the time-frequency plane. In this paper we introduce a new framework that allows the routine use of Bayesian inference for online estimation of the time-varying spectral density of a locally stationary Gaussian process. The core of our approach is the use of a likelihood inspired by a local Whittle approximation. This choice, along with the use of a recursive algorithm for non-parametric estimation of the local spectral density, permits the use of a particle filter for estimating the time-varying spectral density online. We provide demonstrations of the algorithm through tracking chirps and the analysis of musical data

Glaciotectonic Processes Associated with the Central Alpine Fault: A Gravity Study of the Central West Coast, South Island, New Zealand

The rugged topographic relief of the central West Coast reflects ongoing interplay between active tectonic and climatic processes. Major geomorphological features have formed in response to convergence between the Pacific and Australian continental plates, and the principal locus of this collision is the transpressive Alpine Fault. This thesis describes a gravity study of glaciotectonic structures in the footwall of the central Alpine Fault and the processes responsible for their formation. During this study 361 new gravity observations were collected in the Wanganui, Whataroa, Waiho, and Fox river flood plains on the western (footwall) side of the Alpine Fault. When combined with existing gravity observations, the available database comprises 932 measurements over the four catchments. These gravity data are used to produce detailed gravity maps and 2-3/4D gravity models of the subsurface structure below the flood plains. Models reveal extensive glacial erosion focused within the flood plains, with individual glacial channels reaching depths of ~ 800 m. Based on fault-perpendicular models, it is proposed that the South Westland Fault is a transition between a thrust-driven monocline structure in South Westland and the steeply dipping Hohonu reverse fault in North Westland. Using gravity data, dextral off sets on the Alpine Fault since the Last Glacial Maximum have been determined by examining the structure and geomorphology of deeply incised glacial erosional channels. By studying how the lower reaches of the Wanganui, Whataroa, and Fox rivers have been translated with respect to their channels on the eastern (hanging wall) side of the Alpine Fault, horizontal fault displacements have been determined in three of the four catchments. Fault offsets of 383 ± 388 m, 372 ± 88 m, and 450 ± 99 m are estimated for the Wanganui, Whataroa, and Fox River valleys respectively. A range of possible channel formation ages are used to estimate dextral strike-slip movement rates, with the preferred formation age of 19 ± 1 ka yielding rates of 20.2 ± 24.0 mm/yr, 19.6 ± 6.0 mm/yr and 23.7 ± 8.5 mm/yr for the Wanganui, Whataroa, and Fox river valleys respectively