Searching for plasticity in dissociated cortical cultures on multi-electrode arrays

We attempted to induce functional plasticity in dense cultures of cortical cells using stimulation through extracellular electrodes embedded in the culture dish substrate (multi-electrode arrays, or MEAs). We looked for plasticity expressed in changes in spontaneous burst patterns, and in array-wide response patterns to electrical stimuli, following several induction protocols related to those used in the literature, as well as some novel ones. Experiments were performed with spontaneous culture-wide bursting suppressed by either distributed electrical stimulation or by elevated extracellular magnesium concentrations as well as with spontaneous bursting untreated. Changes concomitant with induction were no larger in magnitude than changes that occurred spontaneously, except in one novel protocol in which spontaneous bursts were quieted using distributed electrical stimulation

Observation of the spin Peltier effect

We report the observation of the spin Peltier effect (SPE) in the ferrimagnetic insulator Yttrium Iron Garnet (YIG), i.e. a heat current generated by a spin current flowing through a Platinum (Pt)|YIG interface. The effect can be explained by the spin torque that transforms the spin current in the Pt into a magnon current in the YIG. Via magnon-phonon interactions the magnetic fluctuations modulate the phonon temperature that is detected by a thermopile close to the interface. By finite-element modelling we verify the reciprocity between the spin Peltier and spin Seebeck effect. The observed strong coupling between thermal magnons and phonons in YIG is attractive for nanoscale cooling techniques.Comment: 5 pages, 3 figures, 4 pages supplementary information, 4 supplementary figure

A forgotten frontier zone : settlements and reactions in the Stormberg area between 1820-1860

From Preface: In 1778 Joachim van Plettenberg declared the Fish River as boundary between the Trekboer and the Xhosa. The area between the lower reaches of the Fish and Kei Rivers was to become the main centre of conflict in nine frontier wars. It was here, too, that successive governors carried out experiments to stabilize land and people in the area. But after 1820, while official attention was focused on this trouble spot, a new and related zone of conflict was gradually and almost unnoticed opening up. This was in the north-east where the first encounters between Trekboer and Thembu were beginning to take place. By 1825 the spearhead of the Thembu, harassed by the amaNgwane raids, had migrated across the Kei River to settle south of the Stormberg in what is now the district of Queenstown. By this time the first Trekboers in their perennial search for water and pasturage had crossed the Stormberg Spruit to settle on the waste land north of the Stormberg. The history of the Stormberg area is predominantly an account of the interaction between these two peoples

A history of the Thembu and their relationship with the Cape, 1850-1900

Present day Thembuland is situated roughly between the Mthatha and Kei rivers. It lies within the south-western portion of the political unit which has been known since 1976 as the Republic of Transkei. It comprises the territories formerly known as Emigrant Thembuland (now the districts of Cala and Cofimvaba) and Thembuland Proper, i.e. the districts of Mqanduli, Umtata, Engcobo and Bomvanaland. We have evidence that Thembu people had already settled in Thembu land Proper, at the Mbashe river, by the beginning of the 17th century. Pioneering clans many have entered the territory at a much earlier date. In the 1830's some clans broke away from the Mbashe settlement, and moved to the region of present day Queenstown. In 1853 their lands were included in the so-called Tambookie Location, which in 1871 became the district of Glen Grey. Emigrant Thembuland came into existence in 1865 when four chiefs from Glen Grey accepted Sir Philip Wodehouse's offer to settle on the lands across the White Kei whence the Xhosa chief Sarhili had been expelled in 1857. This thesis deals with the history of the people who lived in these territories between 1850 and 1900

Economic Development and Infrastructure: The Case of Balochistan Province

In designing a future road network, public budget constraints force administrations to make choices. The objective of economic development requires that both efficiency and equity are taken into account. The present analysis operationalises these two concepts by social and economic accessibility in Balochistan. It suggests priorities which can serve as an input for the design of the future road network

Quantitative exposure to livestock-associated MRSA ST398 of pig slaughterhouse workers

Objectives: To quantify livestock-associated MRSA (LA-MRSA) exposure to workers in pig slaughterhouses and assess associated risk factors for carriage in slaughterhouse workers. Methods: A cross-sectional study in three Dutch pig slaughterhouses was undertaken. Nasal swabs of 341 participants, surface wipes, air, and glove samples were screened for presence of MRSA. MRSA was quantitatively determined on gloves and in air samples by culturing and real-time PCR

Basic design and simulation of a SPECT microscope for in vivo stem cell imaging

The need to understand the behavior of individual stem cells at the various stages of their differentiation and to assess the resulting reparative action in pre-clinical model systems, which typically involves laboratory animals, provides the motivation for imaging of stem cells in vivo at high resolution. Our initial focus is to image cells and cellular events at single cell resolution in vivo in shallow tissues (few mm of intervening tissue) in laboratory mice and rates. In order to accomplish this goal we are building a SPECT-based microscope. We based our design on earlier theoretical work with near-field coded apertures and have adjusted the components of the system to meet the real-world demands of instrument construction and of animal imaging. Our instrumental design possesses a reasonable trade-off between field-of-view, sensitivity, and contrast performance (photon penetration). A layered gold aperture containing 100 pinholes and intended for use in coded aperture imaging application has been designed and constructed. A silicon detector connected to a TimePix readout from the CERN collaborative group was selected for use in our prototype microscope because of its ultra-high spatial and energy resolution capabilities. The combination of the source, aperture, and detector has been modeled and the coded aperture reconstruction of simulated sources is presented in this work