Hippocampus-dependent emergence of spatial sequence coding in retrosplenial cortex.

Retrosplenial cortex (RSC) is involved in visuospatial integration and spatial learning, and RSC neurons exhibit discrete, place cell-like sequential activity that resembles the population code of space in hippocampus. To investigate the origins and population dynamics of this activity, we combined longitudinal cellular calcium imaging of dysgranular RSC neurons in mice with excitotoxic hippocampal lesions. We tracked the emergence and stability of RSC spatial activity over consecutive imaging sessions. Overall, spatial activity in RSC was experience-dependent, emerging gradually over time, but, as seen in the hippocampus, the spatial code changed dynamically across days. Bilateral but not unilateral hippocampal lesions impeded the development of spatial activity in RSC. Thus, the emergence of spatial activity in RSC, a major recipient of hippocampal information, depends critically on an intact hippocampus; the indirect connections between the dysgranular RSC and the hippocampus further indicate that hippocampus may exert such influences polysynaptically within neocortex

Stray currents problems in Bohumín railway station

Import 22/07/2015Diplomová práce se zabývá problematikou bludných proudů v bezprostředním okolí vlakové stanice Bohumín. Tato práce přímo navazuje na terénní měření v hale technickohygienické údržby (THU) a jejím nejbližším okolí ve vlakové stanici Bohumín. Hlavním cílem práce je vyhledat cizí vodivé cesty v hale THU a jejím okolí, způsobující poruchy na svodech bleskosvodů chránících halu THU před atmosférickými výboji. Dále pak, v závislosti na provedeném měření, navrhnout a vyhodnotit možné způsoby odstranění zjištěných problémů. Práce se dále zabývá vybranými problémy provozování stejnosměrné trakce, kvalitou zpětné cesty trakčních obvodů, šířením zemních proudů, elektrochemickou korozí a legislativou týkající se problematiky stavby a provozu elektrických drah.This diploma thesis deals with the issue of stray current in immediate surroundings of Bohumín’s train station. The diploma thesis is straight continuation of field measurement in a technical and hygienic maintenance hall (THM) and its nearest surroundings of Bohumín’s train station. The main purpose of this diploma thesis is to find out unfamiliar conductive electrical pathway in THM hall and its surroundings, causing defects to leads of lightning rods that are protecting THM hall against atmospheric discharge. Next purpose is, due to previous measurement, suggest and find out possible ways of removing the identified problems. This dissertation also deals with selected problems of direct-current traction, quality of return pathway of traction circuit, ground current propagation, electrochemical corrosion and legislation that concern issues of construction and operation of electrical railways.410 - Katedra elektroenergetikyvýborn

Towards Single Molecule Imaging Using Nanoelectromechanical Systems

We incorporate nanoelectromechanical systems (NEMS) into a state-of-the-art commercial mass spectrometer (Q Exactive Plus with Orbitrap detection). This unique hybrid instrument is capable of ionizing molecules up to 4.5 MDa in their intact native state, isolating molecules of interest according to their mass-to-charge ratio, performing high resolution mass spectrometry (MS), and delivering those molecules to the NEMS. We use NEMS optimized for detecting the inertial mass of adsorbed species directly, which contrasts with indirect measurements of the mass-to-charge ratio performed with typical instruments. This unique form of mass spectrometry, NEMS-MS, with its single-molecule sensitivity, has promising applications to the fields of proteomics and native mass spectrometry, including deep proteomic profiling, single-cell proteomics, mass spectrometry-based imaging, or identifying viruses in their in vivo state. We analyze intact E. coli GroEL chaperonin, a noncovalent 801 kDa complex consisting of 14 identical subunits. GroEL was sent to NEMS operated with the first two vibrational modes monitored in real time. Molecules physisorbing to the NEMS cause an abrupt shift in its resonance frequencies. The change in resonance frequencies is used to calculate the mass of each molecule. A mass spectrum is compiled with a main peak of 846 kDa, close to the expected value, and a secondary peak resolved near twice the mass of GroEL. Measurements are then performed operating the first three modes simultaneously. Using a technique called inertial imaging, frequency shifts are used to calculate the first three mass moments: mass, position, and variance (size). This is used to distinguish between adsorbates arriving in a single, point-like distribution or a more extended distribution, thus demonstrating a rudimentary form of molecular imaging. Two new theories are presented for analyzing frequency-shift data. The first approach offers a more streamlined approach for calculating the mass moments. This approach is used to improve the mass spectrum of the GroEL calculated using three-mode data, producing a main peak almost fully resolved at 805 kDa. An entirely different approach is presented that allows for obtaining the mass density distribution of an adsorbed molecule (i.e., imaging) with a higher number of modes.</p

A2_3 The Great Eggscape

The movie “Chicken Run” sees a flock of chickens escape certain death by building an aircraft and flying out. By estimating the dimensions of this craft, “The Old Crate”, we calculated that atakeoff speed of 36ms−1 would be required for flight, which gave a kinetic energy of 130 KJ. Reviewing the movie showed that a total of 40 chickens power the craft through pedalling. Assuming 100% efficiency we calculated that the chickens could only supply 3.2 KJ of energy, hence, would not in fact escape their fate

A2_2 Why So Blue?

We determine that the probable source of Dr Manhattan’s blue glow is the ionisation and excitation of nitrogen in the air around him. Through comparison with a filament lighbulb his minimum power output from photon production is estimated. Taking into account the dissociation and ionisation energies of each of the fluorescing molecules provides an upper limit on his power output. These limits are ≈ 470 W and ≈ 3300 W, respectively. Little to no information is given about Dr Manhattan’s physical properties in the source material, and these calculations require many assumptions and approximations

A2_4 'It appears to have gone into orbit, sir'

In this article we calculated the mass and acceleration due to gravity of a planetoid, featured in an episode of the BBC series `Red Dwarf', if a golf ball is hit into orbit. We then compared that result to the portrayal of the crew's movement around the planetoid's surface. We found that the mass of the planetoid is 1.4 x 104% of the mass of the Earth and its acceleration due to gravity is 0.05 m s-2

A2_7 Rise (and Fall) of the Planet of the Apes

We determine the basic physical properties of a new astronomical body created by collecting the entire primate population of the Earth in orbit. We calculate the orbital distance at which the new satellite would exert a tidal force equal in magnitude to that of the moon on the Earth. At 7.2×10^4 m this is found to be three orders of magnitude smaller than the 2.7×10^7 m Roche limit and well within the body of the Earth, suggesting that there is no way such a primate satellite could significantly perturb the Earth

Quasiprobabilistic Interpretation of Weak measurements in Mesoscopic Junctions

The impossibility of measuring noncommuting quantum mechanical observables is one of the most fascinating consequences of the quantum mechanical postulates. Hence, to date the investigation of quantum measurement and projection is a fundamentally interesting topic. We propose to test the concept of weak measurement of noncommuting observables in mesoscopic transport experiments, using a quasiprobablistic description. We derive an inequality for current correlators, which is satisfied by every classical probability but violated by high-frequency fourth-order cumulants in the quantum regime for experimentally feasible parameters.Comment: 4 pages, published versio