Investigation of the boundary layer zone with an aerodynamic flow around an axisymmetric spindle-shaped body for solving conjugate problems of heat and mass transfer

The article discusses the possibility of calculating the thickness of the boundary layer when flowing around an axisymmetric spindle-shaped body without using empirical similarity coefficients. For this, the use of physical analogy of processes is proposed. The necessary flow conditions are described. The two-dimensional Laplace equation is solved for the near-surface region of the laminar flow around the body, obtained by rotating a curve of a given shape. When solving the problems of conjugate heat transfer, the regularities of the interaction of the flow with the body surface are taken into account, which, as a result, is reduced to the joint solution of the boundary layer equations describing the flow field and the heat conduction equations describing the propagation of temperature fields inside and outside the body. In view of the complexity or impossibility of the analytical solution of such problems, it is customary to resort to numerical methods for solving these equations. Even the numerical solution of the conjugate heat transfer problem is associated with a huge number of calculations, the availability of computing power and significant time costs. Therefore, it is customary to solve such problems in a quasi-stationary approximation, which imposes certain restrictions on the scope of application

Hugin+ neurons provide a link between sleep homeostat and circadian clock neurons

Sleep is controlled by homeostatic mechanisms, which drive sleep after wakefulness, and a circadian clock, which confers the 24-h rhythm of sleep. These processes interact with each other to control the timing of sleep in a daily cycle as well as following sleep deprivation. However, the mechanisms by which they interact are poorly understood. We show here that hugin+ neurons, previously identified as neurons that function downstream of the clock to regulate rhythms of locomotor activity, are also targets of the sleep homeostat. Sleep deprivation decreases activity of hugin+ neurons, likely to suppress circadian-driven activity during recovery sleep, and ablation of hugin+ neurons promotes sleep increases generated by activation of the homeostatic sleep locus, the dorsal fan-shaped body (dFB). Also, mutations in peptides produced by the hugin+ locus increase recovery sleep following deprivation. Transsynaptic mapping reveals that hugin+ neurons feed back onto central clock neurons, which also show decreased activity upon sleep loss, in a Hugin peptide–dependent fashion. We propose that hugin+ neurons integrate circadian and sleep signals to modulate circadian circuitry and regulate the timing of sleep.

One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects

The thermal edge flow is a gas flow typically induced near a sharp edge (or a tip) of a uniformly heated flat plate. This flow has potential applicability as a nonmechanical flow controller in microelectromechanical systems (MEMS). However, it has a shortcoming: the thermal edge flows from each edge cancel out, resulting in no net flow. In this study, to circumvent this difficulty, the use of a U-shaped body is proposed and is examined numerically. More specifically, a rarefied gas flow over an array of U-shaped bodies, periodically arranged in a straight channel, is investigated using the direct simulation Monte-Carlo (DSMC) method. The U-shaped bodies are kept at a uniform temperature different from that of the channel. Two types of U-shaped bodies are considered, namely, a square-U shape and a round-U shape. It is demonstrated that a steady one-way flow is induced in the channel for both types. The mass flow rate is obtained for a wide range of the Knudsen numbers, i.e., the ratio of the molecular mean free path to the characteristic size of the U-shape body. For the square-U type, the direction of the overall mass flow is in the same direction for the entire range of the Knudsen numbers investigated. For the round-U type, the direction of the total mass flux is reversed when the Knudsen number is moderate or larger. This reversal of the mass flow rate is attributed to a kind of thermal edge flow induced over the curved part of the round-U-shaped body, which overwhelms the thermal edge flow induced near the tip. The force acting on each of the bodies is also investigated.

The mandible

The mandible is the largest of the facial bones, occupying a prominent position upon and providing the foundation for the lower third of the face. Despite holding the honour of being the strongest bone in the face, its protrusive location makes it vulnerable to injury – particularly in relation to aggressively placed fists, steering wheels and concrete. Anatomically, the mandible consists of a symmetrical, horseshoe shaped body continuous with paired broad rami posteriorly. The former houses the lower teeth within the alveolus whilst the latter provides attachment for the four principle muscles of mastication from the its medial and lateral surfaces and coronoid and condylar processes. In addition to the aforementioned muscles of mastication, the mandible provides origin to the muscles of the tongue, the floor of mouth and some muscles of facial expression.

Viennese vase painted in Dresden (architectural, artistic, stylistic, morphological and structural features)

The article examines the architectural, artistic, stylistic, morphological and structural features of an old porcelain vase from a private Odessa collection. The unpainted vase was made in 1860s at Vienna Porcelain Manufactory. This vase was painted in Helena Wolfsohn’s studio in Dresden between 1864 and 1878 (?). Helena Wolfsohn lived and worked in a significant center of European civilization, culture and arts of her time. The images are painted on the vase using the technique of manual overglaze painting. Amazingly arranged bouquets of flowers are painted on the turquoise background of the oval-shaped body of the vase, and gallant scenes in the Watteau style are depicted on the white parts of the body. On the bottom of the vase base an underglaze blue mark is applied: a shield. The painting of the vase is notable for a vivid pictorial effect, a successful composition, harmony and restraint of color shades. Similar vases painted at Helena Wolfsohn’s studio were exhibited at the International Exhibition in Sydney (1879) and at the World Exhibition in Melbourne (1880). Decorative porcelain vases play an important role in creating the architectural and artistic ensemble of the interior, whose main compositional principle is architectonics.

A neuronal ensemble encoding adaptive choice during sensory conflict in Drosophila

Feeding decisions are fundamental to survival, and decision making is often disrupted in disease. Here, we show that neural activity in a small population of neurons projecting to the fan-shaped body higher-order central brain region of Drosophila represents food choice during sensory conflict. We found that food deprived flies made tradeoffs between appetitive and aversive values of food. We identified an upstream neuropeptidergic and dopaminergic network that relays internal state and other decision-relevant information to a specific subset of fan-shaped body neurons. These neurons were strongly inhibited by the taste of the rejected food choice, suggesting that they encode behavioral food choice. Our findings reveal that fan-shaped body taste responses to food choices are determined not only by taste quality, but also by previous experience (including choice outcome) and hunger state, which are integrated in the fan-shaped body to encode the decision before relay to downstream motor circuits for behavioral implementation.

A neural circuit for wind-guided olfactory navigation

To navigate towards odor in a turbulent environment, animals integrate odor value cues with wind direction cues. The central neural circuits subserving this behavior are unknown. Here we used optogenetic activation to identify neurons in the lateral horn (LH), mushroom body (MB), and fan-shaped body (FB), that drive upwind orientation in walkingDrosophila. Using calcium imaging, we show that MB/LH neurons encode odor independent of wind direction, and that odor and wind are integrated within hΔC local neurons of the FB to drive re-orientation. Based on connectome data, we model an FB circuit that allows odor to switch behavioral orientation to wind. Our work identifies central neural circuits that integrate value and direction signals to generate an essential goal-directed behavior.

A neural circuit linking two sugar sensors regulates satiety-dependent fructose drive in Drosophila

ABSTRACTIngestion of certain sugars leads to activation of fructose sensors within the brain of flies, which then sustain or terminate feeding behavior depending on internal state. Here, we describe a three-part neural circuit that links satiety with fructose sensing. We show that AB-FBl8 neurons of the Fan-shaped body display oscillatory calcium activity when hemolymph glycemia is high, and that these oscillations require synaptic input from SLP-AB neurons projecting from the protocerebrum to the asymmetric body. Suppression of activity in this circuit, either by starvation or genetic silencing, promotes specific drive for fructose ingestion. Moreover, neuropeptidergic signaling by tachykinin bridges fan-shaped body activity and Gr43a-mediated fructose sensing. Together, our results demonstrate how a three-layer neural circuit links the detection of two sugars to impart precise satiety-dependent control over feeding behavior.

Slowly Vibrating Axially Symmetric Bodies-Transverse Flow

Stokes drag on axially symmetric bodies vibrating slowly along the axis of symmetry placed under a uniform transverse flow of the Newtonian fluid is calculated. The axially symmetric bodies of revolution are considered with the condition of continuously turning tangent. The results of drag on sphere, spheroid, deformed sphere, egg-shaped body, cycloidal body, Cassini oval, and hypocycloidal body are found to be new. The numerical values of frictional drag on a slowly vibrating needle shaped body and flat circular disk are calculated as particular cases of deformed sphere.

Transsynaptic mapping of Drosophila mushroom body output neurons

The mushroom body (MB) is a well-characterized associative memory structure within the Drosophila brain. Analyzing MB connectivity using multiple approaches is critical for understanding the functional implications of this structure. Using the genetic anterograde transsynaptic tracing tool, trans-Tango, we identified divergent projections across the brain and convergent downstream targets of the MB output neurons (MBONs). Our analysis revealed at least three separate targets that receive convergent input from MBONs: other MBONs, the fan-shaped body (FSB), and the lateral accessory lobe (LAL). We describe, both anatomically and functionally, a multilayer circuit in which inhibitory and excitatory MBONs converge on the same genetic subset of FSB and LAL neurons. This circuit architecture enables the brain to update and integrate information with previous experience before executing appropriate behavioral responses. Our use of trans-Tango provides a genetically accessible anatomical framework for investigating the functional relevance of components within these complex and interconnected circuits.