Vector lattices

The first of two results is a 1-1-correspondence between isomorphism classes of finite-dimensional vector lattices and finite rooted unlabelled trees. Thus the problem of counting isomorphism classes of finite-dimensional vector lattices reduces to the well-known combinatorial problem of counting these trees. The correspondence is used to identify the class of congruence lattices of finite-dimensional vector lattices as the class of finite dual relative Stone algebras, in partial answer to a question posed by Birkhoff. The next result constructs the lattice of congruences of a finite-dimensional vector lattice, via an algorithm, using the geometry of the positive cone

Growth Height Determination of Tree Walls for Precise Monitoring in Apple Fruit Production Using UAV Photogrammetry

In apple cultivation, spatial information about phenotypic characteristics of tree walls would be beneficial for precise orchard management. Unmanned aerial vehicles (UAVs) can collect 3D structural information of ground surface objects at high resolution in a cost-effective and versatile way by using photogrammetry. The aim of this study is to delineate tree wall height information in an apple orchard applying a low-altitude flight pattern specifically designed for UAVs. This flight pattern implies small distances between the camera sensor and the tree walls when the camera is positioned in an oblique view toward the trees. In this way, it is assured that the depicted tree crown wall area will be largely covered with a larger ground sampling distance than that recorded from a nadir perspective, especially regarding the lower crown sections. Overlapping oblique view images were used to estimate 3D point cloud models by applying structure-from-motion (SfM) methods to calculate tree wall heights from them. The resulting height models were compared with ground-based light detection and ranging (LiDAR) data as reference. It was shown that the tree wall profiles from the UAV point clouds were strongly correlated with the LiDAR point clouds of two years (2018: R2 = 0.83; 2019: R2 = 0.88). However, underestimation of tree wall heights was detected with mean deviations of −0.11 m and −0.18 m for 2018 and 2019, respectively. This is attributed to the weaknesses of the UAV point clouds in resolving the very fine shoots of apple trees. Therefore, the shown approach is suitable for precise orchard management, but it underestimated vertical tree wall expanses, and widened tree gaps need to be accounted for

Conrad Deep: a new northern Red Sea deep. Origin and implications for continental rifting

A previously unknown deep, here called Conrad Deep, was discovered during an extensive geophysical survey of the northern Red Sea in June, 1984. Conrad Deep is located at 27°03’N, 34°43’E, only 90 km south of the Gulf of Suez and is the most northern deep yet discovered in the Red Sea. It is located within a well developed axial depression which also contains Charcot Deep, 100 km to the south. The axial depression is associated with abundant recent deformation and is situated at the peak of a regional heat flow high extending across the rift. Conrad Deep is typical of the small northern type Red Sea Deep. It is 10 km long, 2 km wide and has a maximum depth of 1460 m. It is associated with high and variable heat flow values and large magnetic anomalies. There is no evidence of a dense brine layer. Detailed analysis of the geophysical data implies that the deep probably results from a very recent (< 40,000 years) intrusion into continental type basement. The formation of a well defined axial depression associated with very high heat flow and small deeps resulting from isolated intrusions may be the first step in the transition from continental extension to seafloor spreading

Has the Wharton Basin's Heat flow been perturbed by the formation of a diffuse plate boundary in the Indian Ocean?

The Central Indian Ocean region has heat flow higher than expected for its lithospheric age. This heat flow anomaly is thought to be associated with deformation of sediment and crust and high seismicity. To better constrain the nature of this deformation, we examine the spatial variation of the heat flow. Previous work suggested high heat flux also in the Wharton Basin to the east, which shows less seismicity and deformation. Using new values for lithospheric age from reinterpretation of the magnetic anomalies, we have reexamined the heat flow and found it no higher than expected, in contrast to the Central Indian Basin. This spatial distribution of heat flow highs and expected values is consistent with the pattern of seismicity and deformation and the predictions of the recent diffuse plate boundary model [Wiens et al., 1985] for the region

Evidence for excess pore pressures in southwest Indian Ocean sediments

Brown clay cores from the Madagascar and Crozet basins show the following evidence of excess pore pressures: large amounts of flow-in, increasing average sedimentation rate with age, and nonlinear temperature gradients. Additionally, many hilltops in these basins have no visible sediment cover. The bare hilltops may result from periodic slumping caused by excess pore pressures. Calculated excess pore pressures which equal or exceed the overburden pressure were inferred from water fluxes predicted by nonlinear temperature gradients and laboratory permeability measurements by using Darcy's law. Since pore pressures which exceed the overburden pressure are unreasonable, we attribute this discrepancy to laboratory measurements which underestimate the in situ permeability. The widespread presence of overpressured sediments in areas of irregular topography provides a process for resuspension of clay-sized particles. This mechanism does not require high current velocities for the erosion of clay and therefore can be applied to many areas where no strong currents are evident. Carbonate-rich sediments from the Madagascar Ridge, the Mozambique Ridge, and the Agulhas Plateau had almost no flow-in and occurred in areas where all topography was thickly draped with sediment. Since the age and tectonic location of the ridges and plateaus preclude water circulation in the basement, we attribute these differences between the brown clay and the carbonate-rich material to an absence of significant excess pore pressures in the plateau and ridge sediments

Anomalous heat flow in the northwest Atlantic: A case for continued hydrothermal circulation in 80-M.Y. crust

A detailed study of a 60×150 km area at 60°W, 24°N at the eastern end of the Nares Abyssal Plain indicates that hydrothermal circulation is still active in the 80 m.y. B.P. oceanic crust. The 58 heat flow measurements made at five stations in the area have revealed (1) constant heat flow over the abyssal plain (56 mW m−2), (2) a cyclic heat flow over the abyssal hills (mean of 77 mW m−2), and (3) a large anomaly of 710 m W m−2 over one of several small domes which protrude from the abyssal plain. The domes are 0.5–1.0 km in diameter near the top and rise 50 m above the level of the abyssal plain. They are recognized from surface echo sounders by an abrupt disappearance in the abyssal plain subbottom reflectors, but on near-bottom pinger records they appear as steep-walled structures which are covered by ∼10 m of sediment (compared to ∼75 m on the surrounding abyssal hills). From analogy with active ridge crests, these features are probably small volcanoes. The heat flow anomaly over one of the domes is matched well by a finite element convection model with the following characteristics: (1) recharge at one basement outcrop and discharge at another, (2) 300 m of sediment fill between outcrops, and (3) permeabilities of 10−10 cm2 for basalt and 10−13 cm2 for sediment. In other words, we believe that there is very effective convective heat transfer within the crust and out of the relatively permeable, thinly sedimented basement dome, resulting in the local high heat flow. Overall, the results from the Nares survey vividly show the age independent muting effect of sediment on the surface manifestation of crustal convection. In our survey area the mode of heat transfer varies from purely conductive in the more thickly sedimented abyssal plain areas (∼300 m sediment cover) to moderate amplitude convection pattern beneath the abyssal hills (∼75 m sediment cover) to a very large thermal anomaly over the small dome or ‘chimneylike’ structure (∼10 m sediment cover). The domes are possibly active analogues to the presently inactive basement chimney drilled at DSDP site 417A

Growth Height Determination of Tree Walls for Precise Monitoring in Apple Fruit Production Using UAV Photogrammetry

In apple cultivation, spatial information about phenotypic characteristics of tree walls would be beneficial for precise orchard management. Unmanned aerial vehicles (UAVs) can collect 3D structural information of ground surface objects at high resolution in a cost-effective and versatile way by using photogrammetry. The aim of this study is to delineate tree wall height information in an apple orchard applying a low-altitude flight pattern specifically designed for UAVs. This flight pattern implies small distances between the camera sensor and the tree walls when the camera is positioned in an oblique view toward the trees. In this way, it is assured that the depicted tree crown wall area will be largely covered with a larger ground sampling distance than that recorded from a nadir perspective, especially regarding the lower crown sections. Overlapping oblique view images were used to estimate 3D point cloud models by applying structure-from-motion (SfM) methods to calculate tree wall heights from them. The resulting height models were compared with ground-based light detection and ranging (LiDAR) data as reference. It was shown that the tree wall profiles from the UAV point clouds were strongly correlated with the LiDAR point clouds of two years (2018: R2 = 0.83; 2019: R2 = 0.88). However, underestimation of tree wall heights was detected with mean deviations of −0.11 m and −0.18 m for 2018 and 2019, respectively. This is attributed to the weaknesses of the UAV point clouds in resolving the very fine shoots of apple trees. Therefore, the shown approach is suitable for precise orchard management, but it underestimated vertical tree wall expanses, and widened tree gaps need to be accounted for.BMEL, 2814903915, Verbundprojekt: Entwicklung einer flugrobotergestützten Expertenplattform für einen präzisen Pflanzenschutz im Erwerbsobstbau (Corona-PRO) - Teilprojekt

Marx’s Theory of Revolutionary Change

G. A. Cohen’s pathbreaking book, Karl Marx‘s Theory of History: A Defence (1978), prompted extensive reconsideration of historical materialism. This effort recast ongoing debates about Marx‘s theory of history by defending the view that historical materialism embodies a set of substantive claims as appropriately subject to analytical scrutiny as those of any other viable theory. Specifically, Cohen advances one central substantive claim that summarizes his reading of the “Preface” to A Contribution to the Critique of Political Economy. “History is, fundamentally, the growth of productive power, and forms of society rise and fall according as they enable or impede that growth.” This premise affirms that the same set of factors that explain changes societies undergo within a given historical epoch also explain transitions between historical epochs. The theoretical account of intraepochal historical development suffices equally to cover interepochal, revolutionary change. In this paper we reject this premise and argue that even on the most plausible reconstruction of Marx’s theory of history—a reconstruction that employs, among other things, a careful ownership-based criterion of historical epochs and the use of functional explanations—Marx’s theory of history cannot explain social revolutions

Correlated sediment thickness, temperature gradient and excess pore pressure in a marine fault block basin

Measurements of temperature gradient and excess pore pressure in the surficial sediment of a fault block basin in the Guatemala Basin correlate with sediment thickness. The temperature gradient is smaller and the excess pore pressure gradient is more negative in areas of thinner sediment. This correlation is explained by postulating downward pore water advection within the sediments, with flow velocities on the order of 10−9 to 10−8 m/s in the thinnest sediments and much less flow in the thickest sediments. Sediment physical properties and pore water chemistry also support this interpretation. Since the conductive heat flow of the basin as a whole is less than one third that predicted by sea floor spreading models, the oceanic basement may be the site of a vigorous hydrothermal circulation system. The pore water advection in the sediments may be driven by this larger scale circulation

New frog

6 p. : ill. ; 24 cm.Includes 1 bibliographical reference (p. 6)