Evidence has accumulated to support a model for odorant detection in which individual olfactory receptor neurons (ORNs) express one of a large family of G protein-coupled receptor proteins that are activated by a small number of closely related volatile chemicals. However, the issue of whether an individual ORN expresses one or multiple types of receptor proteins has yet to be definitively addressed. Physiological data indicate that some individual ORNs can be activated by odorants differing substantially in structure and/or perceived quality, suggesting multiple receptors or one nonspecific receptor per cell. In contrast, molecular biological studies favor a scheme with a single, fairly selective receptor per cell. The present studies directly assessed whether individual rat ORNs can express multiple receptors using single-cell PCR techniques with degenerate primers designed to amplify a wide variety of receptor sequences. We found that whereas only a single OR sequence was obtained from most ORNs examined, one ORN produced two distinct receptor sequences that represented different receptor gene families. Double-label in situ hybridization studies indicated that a subset of ORNs co-express two distinct receptor mRNAs. A laminar segregation analysis of the cell nuclei of ORNs labeled with the two OR mRNA probes showed that for one probe, the histogram of the distribution of the cell nuclei along the depth of the epithelium was bimodal, with one peak overlapping the (unimodal) histogram for the other probe. These results are consistent with co-expression of two OR mRNAs in a population of single ORNs.

doi: bioRxiv preprint python package (https://deepforest.readthedocs.io/). The data and models have been uploaded to 23

A hereditary property P (k) is a class of k-graphs closed under isomorphism and taking induced sub-hypergraphs. Let P (k) n denote those k-graphs of P (k) on vertex set {1, . . . ,n}. We prove an asymptotic formula for log 2 |P (k) n | in terms of a Turán-type function concerning forbidden induced sub-hypergraphs. This result complements several existing theorems for hereditary and monotone graph and hypergraph properties.

The InSight lander carried an Instrument Deployment System (IDS) that included an Instrument Deployment Arm (IDA), scoop, five finger “claw” grapple, forearm-mounted Instrument Deployment Camera (IDC) requiring arm motion to image a target, and lander-mounted Instrument Context Camera (ICC), designed to image the workspace, and to place the instruments onto the surface. As originally proposed, the IDS included a previously built arm and flight spare black and white cameras and had no science objectives or requirements, or expectation to be used after instrument deployment (90 sols). During project development the detectors were upgraded to color, and it was recognized that the arm could be used to carry out a wide variety of activities that would enable both geology and physical properties investigations. During surface operations for two martian years, the IDA was used during major campaigns to image the surface around the lander, to deploy the instruments, to assist the mole in penetrating beneath the surface, to bury a portion of the seismometer tether, to clean dust from the solar arrays to increase power, and to conduct a surface geology investigation including soil mechanics and physical properties experiments. No other surface mission has engaged in such a sustained and varied campaign of arm and scoop activities directed at such a diverse suite of objectives. Images close to the surface and continuous meteorology measurements provided important constraints on the threshold friction wind speed needed to initiate aeolian saltation and surface creep. The IDA was used extensively for almost 22 months to assist the mole in penetrating into the subsurface. Soil was scraped into piles and dumped onto the seismometer tether six times in an attempt to bury the tether and $\sim30\%$ ∼ 30 % was entrained in the wind and dispersed downwind 1-2 m, darkening the surface. Seven solar array cleaning experiments were conducted by dumping scoops of soil from 35 cm above the lander deck during periods of high wind that dispersed the sand onto the panels that kicked dust off of the panels into suspension in the atmosphere, thereby increasing the power by ∼15% during this period. Final IDA activities included an indentation experiment that used the IDA scoop to push on the ground to measure the plastic deformation of the soil that complemented soil mechanics measurements from scoop interactions with the surface, and two experiments in which SEIS measured the tilt from the arm pressing on the ground to derive near surface elastic properties.

The fine-scale textures of rock surfaces reflect a complex interplay of geologic processes that include those related to rock formation, exposure, weathering, and erosion. Typically, such features are studied in two dimensions using forensic geological techniques from scales from those visible to the naked eye to those in a wider-area context. Rock surface metrology is an emergent technique in which extremely fine-scale textural information is measured in 3D using laboratory instruments. Here we describe its application on the surface of Mars. With the advent of sub-millimeter resolution (14-100 µm per pixel) imaging on Mars, a relatively low-cost (i.e., camera-based) approach for computing quantitative relief models (QRM) of rock surfaces has been investigated. We present preliminary assessment of 20 different martian rock surfaces using this QRM technique; the observations have implications regarding the depositional, diagenetic, and weathering/erosional history of sedimentary rocks on Mars.The Mars Science Laboratory (MSL) Curiosity rover landed in Gale crater, Mars, to investigate a portion of the 5-km-thick stratigraphic section of largely sedimentary rocks exposed within the crater. These rocks display records of depositional and diagenetic environments thought to be ~3.6 billion years old and include fluvial conglomerates; fluvial, deltaic, and eolian sandstones; and lacustrine mudstones [1]. The Mars Hand Lens Imager (MAHLI) is a 2-megapixel Bayer pattern micro-filtered color camera with a focusable macro lens mounted on the turret at the end of Curiosity's robotic arm [2]. We used MAHLI to acquire sets of 5 overlapping frames arranged in a "+" pattern with ~31 µm/pixel resolution to compute QRMs at scales never before possible on natural planetary surfaces [3]. These QRM's allow analysis and interpretation of geologic surfaces at horizontal scales as fine as 100 µm, akin to nondestructive engineering metrology approaches. In principle, the quantitative textural information that QRMs convey for exposed rock surfaces on Mars is tied directly to the cumulative processes that formed, emplaced, and modified them. Thus, our QRM analysis of 20 different Mars rock surfaces offers a new opportunity to extract information about the depositional, diagenetic, and in situ weathering processes on Mars at spatial scales greater than 0.1 mm, extending the array of information about the role of diagenesis and other processes on Mars from mm-scale chemistry (i.e., ChemCam on Curiosity). We generated a series of QRM datasets, starting with a high-silica sandstone known as Greenstone (Sol 1130) and continuing to our latest rock surface targets named Belle Lake (Sol 1586) and Misery (Sol 1593). We analyzed the spatial and vertical distribution of rock surface 'texture elements' at multiple scales, from 0.1 mm to several mm in an effort to unravel their geologic histories. Critical to understanding the geologic phenomena captured in the QRMs are quantitative comparisons with terrestrial reference surfaces, which is an effort...