Mars promotes dTACC dephosphorylation on mitotic spindles to ensure spindle stability

Microtubule-associated proteins (MAPs) ensure the fidelity of chromosome segregation by controlling microtubule (MT) dynamics and mitotic spindle stability. However, many aspects of MAP function and regulation are poorly understood in a developmental context. We show that mars, which encodes a Drosophila melanogaster member of the hepatoma up-regulated protein family of MAPs, is essential for MT stabilization during early embryogenesis. As well as associating with spindle MTs in vivo, Mars binds directly to protein phosphatase 1 (PP1) and coimmunoprecipitates from embryo extracts with minispindles and Drosophila transforming acidic coiled-coil (dTACC), two MAPs that function as spindle assembly factors. Disruption of binding to PP1 or loss of mars function results in elevated levels of phosphorylated dTACC on spindles. A nonphosphorylatable form of dTACC is capable of rescuing the lethality of mars mutants. We propose that Mars mediates spatially controlled dephosphorylation of dTACC, which is critical for spindle stabilization

Fractal dimension and human aquatic locomotion

The aim was to investigate the fractal properties of human swimming and analyze its relationship with swimming kinematics. Eighty-two male swimmers from the local level up to World-ranked athletes undertook a set of 3x25m maximal trials at Front-Crawl. Fractal dimension (D) was calculated from the speed-time series collected with a speedo-meter. It was also calculated the speed fluctuation as an energy cost estimator. Human swimming showed fractal properties (1?D?2). The relationship between D and dv was very high analyzed in absolute values (R2=0.88; s=0.18;

Bluff-body wake encounter and tandem wing-tail wake dynamics in forced harmonic pitch

Wake phenomena and its encounter with downstream bodies are of engineering importance as it can affect aerodynamic loads. This can induce unfavourable-or even dangerous-conditions to aircraft through a loss of lift, or stability and control. Such scenarios range from the local interactions between an aircraft wing and its empennage, to wakes emanated from buildings acting on a helicopter fuselage downstream. Therefore, wake physics must be evaluated to predict any consequential aerodynamic effects. Furthermore, accurately modelling turbulent wake regimes are challenging, as obtaining physically meaningful data requires high-fidelity techniques. In this thesis, canonical cases under static and dynamic conditions focusing on wake encounters are investigated computationally to address these concerns. This is achieved using a Detached-Eddy Simulation (DES) approach that will be validated with a static case before expanding to include overset methods to induce dynamic grid motion on a tandem configuration. Validation is performed by investigating the vortex shedding behaviour and wake characteristics of a separated flow over a square beam bluff-body. Spectral analyses of surface-forces reveal von Karman street dynamics with frequency correlations in the freestream-parallel and cross-stream directions. Metrics are verified against benchmark experimental data, where a considerable aerodynamic impact is implied by both first- and second-moment wake statistics up to a measured downstream distance of six characteristic lengths. The extent of numerical treatment is further demonstrated through validation of its shear-stresses, an auto-correlation function of point-probed velocities, while coherence is observed as peak frequencies correspond to surface vortex shedding frequency. This case is then subsequently used as a wake generator for the investigation of its aerodynamic impact downstream. A NACA0012 wing-section is placed three characteristic lengths downstream for insights on the aerodynamic effects of the bluff-body wake encounter. Time-averaged surface-forces on the wing-section are evaluated against a wake-free condition of the airfoil for reference. The wake encounter demonstrates a decrease in overall pressure distribution from wake-induced separation, with a strong correlation in lift response with the bluff-body vortex shedding dynamics. Instantaneous contours reveal flow behaviour resembling those expected of heave dynamics caused by the alternating vortex street. As oscillatory lift characteristics are induced, the work proposes approximating this response with the Sear's and Theodorsen's functions represented as a relative harmonic motion to the wake based on reduced frequency. Finally, expanding this framework to include overset grids accomplishes dynamic motion for forced harmonic pitching on a tandem wing-tail configuration. This subjects the horizontal stabilizer to a wake induced by pitch oscillations of its main wing located upstream. As this is a single rigid system with a rotational centre on the wing chord, it is observed that the moment arm translates to a coupled pitch-heave motion at the tail. In addition, a separated wake with characteristic leading and trailing edge vortices (LEV/TEVs) is emanated from the wing at the higher angles-of-attack in the harmonic pitch cycles. This leads to a direct correlation in wing-tail dynamics where the tail lift response can be distinguished into two components; the combination of its pitch-heave directly contributed by the tail moment arm, and a gust component by periodically encountering the separated wing wake. The combination of these mechanisms synthesises the tails response from both forced harmonic motion and wing wake interaction, and is shown to be significant to the entire (wing-tail) system. This contributes to novel insights on wake interactions, as the computational framework advances the understanding of tandem aerodynamic relationships under dynamic conditions

A preliminary study on the diagnosis of coral reef healthiness and establishment of coral replenishment technology

Abstract only.Field surveys for coral reef through line-intercept-transect (LIT) and temperature profiling using data-loggers were done at three layers of 5, 10, and 15 m depths in coral reef areas, Nogas Island, Anini-y, Antique, Philippines. Preliminary data based on the LIT survey showed that both coverages of substrates by any type of organism and by Scleractinia decreased in the deeper layers. For Scleractinia, Porites sp. occurred predominantly in all the depth layers with the occurrence decreasing with depth. Temperature fluctuation was largest in the 5 m depth layer, where effects of tidal level were also confirmed. While the average temperature decreased with depth, this did not differ beyond 1°C between 5 and 15 m layers during November 2012 to March 2013. Fragments of the Porites sp. and Acropora sp. were sampled and transferred to aquaria at the Tigbauan Main Station of SEAFDEC/AQD. Acropora sp. sampled from the deepest layer alone showed bleaching and thereafter, a part of the fragments regained the color. Experimental trials to clarify the effects of ocean acidification and warming on the health of the coral using the live fragments of Porites sp. showed decreasing trends in both photosynthetic rates and daily growth rates in acidic condition (pH = 7.6), while decrease of zooxanthellae density was observed under warmer conditions (31°C ) for one month. A new methodology for the determination of density of zooxanthellae was established using the fragments of Porites sp. In this study, the need for studies on several coral communities as well as further basic research on coral biology, particularly, responses to the changing environments are discussed for diagnosis of coral reef healthiness and establishment of effective coral replenishment technology

Sustainable Smart Transportation System: Through the Lens of a Smart City in an Emerging Country

Environmental and social sustainability continue to challenge urban development agendas, especially in emerging markets. Past literature on the topic of smart, sustainable cities has focused relatively less on developing countries – however, during the transient phase, such economies undergo several stages of development which this paper endeavors to investigate. The goal is to define key dimensions essential for evolving existing urban sites into a sustainable ecosystem. In this context, this study puts forward a framework consisting of five pillars: Scalability, Connection, Availability, Productivity, and Environment (SCAPE) to guide the implementation of sustainable cities in developing and tropical countries

Coevolutionary Diagenesis in Tight Sandstone and Shale Reservoirs within Lacustrine-Delta Systems: A Case Study from the Lianggaoshan Formation in the Eastern Sichuan Basin, Southwest China

Tight sandstone and shale oil and gas are the key targets of unconventional oil and gas exploration in the lake-delta sedimentary systems of China. Understanding the coevolutionary diagenesis of sandstone and shale reservoirs is crucial for the prediction of reservoir quality, ahead of drilling, in such systems. Thin-section description, scanning electron microscopy (SEM), X-ray diffraction (XRD), fluid inclusion analysis, porosity and permeability tests, high-pressure mercury intrusion (HPMI) measurements and nuclear magnetic resonance tests (NMR) were used to reveal the coevolutionary diagenetic mechanisms of a sandstone and shale reservoir in the Lianggaoshan Formation of the Eastern Sichuan Basin, China. The thermally mature, organic-matter-rich, dark shale of layer3 is the most important source rock within the Lianggaoshan Formation. It started to generate abundant organic acids at the early stage of mesodiagenesis and produced abundant hydrocarbons in the early Cretaceous. Porewater with high concentrations of Ca2+ and CO32− entered the sandstone reservoir from dark shale as the shale was compacted during burial. Potassium feldspar dissolution at the boundary of the sandstone was more pervasive than at the center of the sandstone. The K+ released by potassium feldspar dissolution migrated from the sandstone into mudstone. Grain-rimming chlorite coats occurred mainly in the center of the sandstone. Some silica exported from the shale was imported by the sandstone boundary and precipitated close to the shale/sandstone boundary. Some intergranular dissolution pores and intercrystal pores were formed in the shale due to dissolution during the early stages of mesodiagenesis. Chlorite coats, which precipitated during eodiagenesis, were beneficial to the protection of primary pore space in the sandstone. Calcite cement, which preferentially precipitated at the boundary of sandstone, was not conducive to reservoir development. Dissolution mainly occurred at the early stage of mesodiagenesis due to organic acids derived from the dark shale. Calcite cement could also protect some primary pores from compaction and release pore space following dissolution. The porosity of sandstone and shale was mainly controlled by the thickness of sandstone and dark shale

Flipping the switches: CD40 and CD45 modulation of microglial activation states in HIV associated dementia (HAD)

Microglial dysfunction is associated with the pathogenesis and progression of a number of neurodegenerative disorders including HIV associated dementia (HAD). HIV promotion of an M1 antigen presenting cell (APC) - like microglial phenotype, through the promotion of CD40 activity, may impair endogenous mechanisms important for amyloid- beta (Aβ) protein clearance. Further, a chronic pro-inflammatory cycle is established in this manner. CD45 is a protein tyrosine phosphatase receptor which negatively regulates CD40L-CD40-induced microglial M1 activation; an effect leading to the promotion of an M2 phenotype better suited to phagocytose and clear Aβ. Moreover, this CD45 mediated activation state appears to dampen harmful cytokine production. As such, this property of microglial CD45 as a regulatory "off switch" for a CD40-promoted M1, APC-type microglia activation phenotype may represent a critical therapeutic target for the prevention and treatment of neurodegeneration, as well as microglial dysfunction, found in patients with HAD

Improving Sparse Representation-Based Classification Using Local Principal Component Analysis

Sparse representation-based classification (SRC), proposed by Wright et al., seeks the sparsest decomposition of a test sample over the dictionary of training samples, with classification to the most-contributing class. Because it assumes test samples can be written as linear combinations of their same-class training samples, the success of SRC depends on the size and representativeness of the training set. Our proposed classification algorithm enlarges the training set by using local principal component analysis to approximate the basis vectors of the tangent hyperplane of the class manifold at each training sample. The dictionary in SRC is replaced by a local dictionary that adapts to the test sample and includes training samples and their corresponding tangent basis vectors. We use a synthetic data set and three face databases to demonstrate that this method can achieve higher classification accuracy than SRC in cases of sparse sampling, nonlinear class manifolds, and stringent dimension reduction.Comment: Published in "Computational Intelligence for Pattern Recognition," editors Shyi-Ming Chen and Witold Pedrycz. The original publication is available at http://www.springerlink.co

Wing-Tail Interaction Under Forced Harmonic Pitch

A wing-tail tandem configuration undergoing forced harmonic pitch is numerically simulated using Detached-Eddy Simulation (DES) coupled with an overset grid. This subjects a tail to a wing wake induced through forced pitch oscillations (Re=21,400, k=0.1). The study therefore captures a flow separated wake with characteristic Leading and Trailing Edge Vortices (LEV/TEVs) emanated from the wing at the higher angles-of-attack in the harmonic pitch cycles. These vortices convect downstream to interact with the tail, which are shown to be significant to its loads. Assessing the tandem system individually shows that their lift dynamics can be empirically approximated using the Theodorsen's function, but limited by stall characteristics and variances in tail lift from the wing wake encounter. This leads to a direct correlation in wing-tail dynamics where the tail lift response can be distinguished into two components; the combination of its pitch-heave by the tail moment arm, and as a periodic gust based on the separated wing wake. The periodicity and phase lag of the wake encounter by the tail suggests that wake effects are accounted for with a gust component as a function of the convective tail length. The combination of these mechanisms synthesises the tails response from both forced harmonic motion and wing wake interaction, and is shown to be significant to the entire system. This contributes to insights on wake interactions in tandem configurations under dynamic conditions