Geoelectric Signatures of Shaft Tombs in the Guachimontones Region, Western Mexico

In the early 1970s a series of over two dozen unlooted shaft tombs were excavated by the Instituto Nacional de Antropología e Historia in the valley of Guadalajara, Jalisco. They still provide the most representative sample of a shaft tomb cemetery known from western Mexico, and they are an underutilized resource for demonstrating significant degrees of social inequality. Here we summarize the findings of the original research in light of more recent work in Jalisco. We aim to demonstrate that the Tabachines cemetery in particular provides evidence for significant social inequalities in the society that built these shaft tombs, that there were significant social changes partway through the Tabachines phase, and that the mortuary ritual practiced in the tombs shows some commonalities with other areas of Mesoamerica.

Intelligent manufacturing requires significant technological interventions to interface manufacturing processes with computational tools in order to dynamically mold the systems. In this era of the 4th industrial revolution, Artificial neural network (ANNs) is a modern tool equipped with a better learning capability (based on the past experience or history data) and assists in intelligent manufacturing. This research paper reports on ANNs based intelligent modelling of a turning process. The central composite design is used as a data-driven modelling tool and huge input–output is generated to train the neural networks. ANNs are trained with the data collected from the physics-based models by using back-propagation algorithm (BP), genetic algorithm (GA), artificial bee colony (ABC), and BP algorithm trained with self-feedback loop. The ANNs are trained and developed as both forward and reverse mapping models. Forward modelling aims at predicting a set of machining quality characteristics (i.e. surface roughness, cylindricity error, circularity error, and material removal rate) for the known combinations of cutting parameters (i.e. cutting speed, feed rate, depth of cut, and nose radius). Reverse modelling aims at predicting the cutting parameters for the desired machining quality characteristics. The parametric study has been conducted for all the developed neural networks (BPNN, GA-NN, RNN, ABC-NN) to optimize neural network parameters. The performance of neural network models has been tested with the help of ten test cases. The network predicted results are found in-line with the experimental values for both forward and reverse models. The neural network models namely, RNN and ABC-NN have shown better performance in forward and reverse modelling. The forward modelling results could help any novice user for off-line monitoring, that could predict the output without conducting the actual experiments. Reverse modelling prediction would help to dynamically adjust the cutting parameters in CNC machine to obtain the desired machining quality characteristics.

In this paper, we report an intelligent model based on ANN to optimize the performance of an internally cooled membrane-based liquid desiccant dehumidifier (IMLDD). IMLDD can effectively mitigate dehumidification deterioration caused by changes in the temperature of the desiccant solution. The mediums of desiccant solution and air are isolated by means of a semi-permeable membrane on both sides in the IMLDD. The temperature of the desiccant solution is reduced by the cooling media that flows through the tubes placed within the solution channels. Generally, many fluid flow parameters like air, cooling water, desiccant solution, etc., play a critical role in controlling the performance of an IMLDD. For our study, inlet air temperature (Tai), inlet concentration of the desiccant solution (Cdsi), flow rate of the desiccant solution at the inlet and inlet cooling temperature of water (Tcwi) have been considered as the operating parameters/conditions. The outputs or responses namely dehumidification efficiency (ηdh), Exergy efficiency (ηex), and unmatched coefficient (ξum) analyze the performance of the IMLDD. The data comprising of massive input-output was achieved using the response surface methodology (RSM) based central composite design (CCD). Back propagation algorithm (BP), artificial bee colony (ABC), and genetic algorithm (GA) models were used to train the neural network (NN) parameters using the data collected from the CCD based response equation. Forward and reverse mapping models were developed using the trained ANNs. Forward modeling predicts the performance parameters of the IMLDD (i.e., ηdh, ηex, and ξuc) for known combinations of operating parameters (i.e., Tai, Cdsi, Tcwi). Similarly, reverse modeling aims at predicting the operating conditions for a known set of performance parameters. The performances of the employed NN models were tested using fifteen arbitrarily generated test cases. The experimental and neural network predicted results were found to be in line with each other for both forward and reverse models. The forward modeling results could assist engineers with off-line tracking, by predicting the response without executing experiments. The reverse modeling prediction will aid in dynamically adjusting the operating parameters to achieve the optimal thermodynamic output characteristics.

In this letter, the authors present archeological evidence of the presence of cleft lip and/or palate (CLP) in pre-Hispanic Mesoamerica. During years 2016 and 2017, the authors visited 5 anthropology museums in Mexico, Guatemala, and El Salvador, in search for pre-Hispanic archeological evidence of CLP, and 16 anthropomorphic figurines with evidence of CLP were identified; 9 at the Anahuacalli Museum, 6 at the National Anthropology Museum of Mexico, and 1 at the National Anthropology Museum of El Salvador. Fifteen of these ceramics originated from the shaft tombs (pre-Hispanic culture from western Mexico, Jalisco, Colima, and Nayarit; dating from 200 bc-600 ad), and 1 ceramic originated from the Cotzumalguapa (a pre-Hispanic culture from western El Salvador dating from 200 ad-900 ad).

Epiclassic occupants of the site of La Quemada left the disarticulated remains of 11-14 humans in an apparently sacred structure outside the monumental core of the site. Several lines of evidence are reviewed to generate propositions about the ritual meanings and functions of the bones. A comparative analysis reveals the complexity of mortuary practices in northern and western Mexico, and permits the suggestion that these particular remains were those of revered ancestors or community members. The sacred structure is seen as a charnel house, in which the more ancient tradition of ancestor worship expressed in shaft tombs was essentially perpetuated above ground. Hostile social relations are clearly suggested, however, by other categories of bone deposits. Recognition of the rich variability of mortuary displays leads to questions about their role in the maintenance of the social order.

Tomb architecture in China has a rich history and is characterized by its diversity, complexity, and symbolism. In different geographical and cultural contexts, “architecture” is often defined differently and includes different topics. For this article, the “tomb architecture” focuses on the architectural matters of early Chinese tombs, such as the construction and the internal and external structures. Literature regarding the funerary traditions in general and the buried artefacts (the grave goods) is rich but not covered here. In China, the earliest tomb construction emerged in the Neolithic period. From 7000 to 5000 bce, communal cemeteries appeared in some early societies. These cemeteries were often located either in or near residential areas. The common type of tomb was the so-called shaft tomb, or pit tomb, which was built by digging a vertical pit in the ground to hold the body and the grave goods. From 5000 to 2000 bce, most tombs continued to use this structure, although the inequality among buried individuals, indicated by the quantity and quality of the grave goods, increased significantly. In many tombs, timber coffins or nested coffins were used to hold the deceased. In some tombs, additional structures such as the secondary ledge (ercengtai二层台), an earthen surface constructed along the pit walls; the waist pit (yaokeng腰坑), an additional small pit under the coffin; and the niche (bikan壁龛), a recess on the wall were added, facilitating the needs to accommodate and display more grave goods. The first radical change to this shaft tomb tradition occurred in the late Shang period (c. 1250–1046 bce). Elite tombs, both in Anyang and its neighboring regions, became much larger, deeper, and more complicated than their forerunners. In Anyang, some large tombs were constructed at a special, moat-surrounded location, providing the earliest example of a cemetery complex separated from residential districts. The Zhou elites inherited these architectural inventions after they conquered Shang. During the Zhou period (c. 1045–256 bce), there was increasing interregional exchange. Elite tombs of the Zhou period not only became much bigger but also added new elements from various origins, such as the tomb mound (fengtu封土) and the horizontal division of the interior space, often by adopting a multichamber structure. These changes led to the tomb of the First Emperor (reign 221–210 bce), which was also the grandest tomb in East Asia in the first millennium bce. In the following Han period (206 bce–220 ce), new changes appeared in tomb architecture. In particular, chamber tombs, sometimes cut on the rocks and with horizontal rooms (chambers), replaced vertical shaft tombs and became the major tomb type, especially for royal and high-elite members. This horizontal tomb architecture became a predominant standard in later dynasties.

This Neotropical, fossorial bug feeds on the roots of banana and other plants. In laboratory experiments it penetrated light soils more rapidly than heavy soils, but extremely dry and very wet soils were not penetrated and the insect survived exposure to excessive water rather poorly. Although starved insects survived rather well in moist soil, those removed from soil lost water rapidly and became desiccated in a few hours. In vertical chambers containing uniformly moist soil, both sexes responded positively and strongly to gravity; in both vertical and horizontal chambers, each containing two samples of soil that differed only in moisture content, both sexes responded positively and strongly to moisture. When S. divergens was presented with conflicting stimuli in vertical chambers (moist soil above the interface, dry soil and gravity below), both sexes reacted positively toward moisture, temporarily becoming negatively geotactic in this situation. The intensity of the moisture response was directly related to the difference in moisture content between the alternative soils, and inversely related to the moisture content of the drier soil. In horizontal chambers the mean distances that the insects moved from the interface into alternative moist and dry soils were not significantly different, which indicates that differences in soil consistency, as affected by moisture content, did not bias the insects' response to soil moisture. By ablation of successive antennal segments, the moisture receptors were localized on antennal segments 3 and 4 in the male and 1 through 4 in the female. With both sexes the intensity of the reaction was a function of the number of receptor-bearing segments remaining on the antennae. Specific moisturesensitive sensilla were not identified.

Motivation Natural gas hydrates are an icy solid consisting commonly of a methane molecule encased by a water lattice. Hydrates occur in vast quantities worldwide, and are found in marine and permafrost regions where their stability conditions are satisfied. Natural gas hydrates are a potential energy resource, a geohazard for drilling and submarine slope stability, and a source of methane a significant greenhouse gas. Traditionally seismic methods are used for hydrate detection since hydrates are often characterized by the bottom simulating reflector (BSR). The BSR often represents the phase change from solid hydrate above to free gas below at a depth controlled by the intercept of the hydrate stability field and the geothermal gradient. While a seismic BSR can be ubiquitous over an entire hydratebearing region, seismic methods do not indicate the gradational upper surface of the hydrate, nor do they provide a distinctive signature within the hydrate zone (Yuan et al., 2000). Furthermore, there are places where hydrates are known to exist yet exhibit no BSR, such as in the Gulf of Mexico (Sloan, 1998). Other methods for hydrate detection include resistivity measurements in well logs. Hydrates are electrical insulators and will be more resistive than the surrounding host sediment, thus providing an EM target. Although the resistivity contrast can be quite small (?2 Ohm-m, Hyndman et al, 1999) our forward modeling results (below) indicate we will be able to detect hydrate using standard electromagnetic methods. We investigate the potential of electromagnetic methods to map the extent and quantity of gas hydrates. A pilot marine EM study at Hydrate Ridge, Oregon was conducted in August, 2004. We collected an extensive data set consisting of magnetotelluric (MT), controlled source electromagnetics (CSEM), and controlled source magnetotelluric (CSMT) data. In this paper we present an outline of our experimental design, a description of our survey, and preliminary results from a subset of the CSEM data. Figure 1. Forward Modeling study of hydrates compared to a background sediment without hydrate. Figure a (top) shows the ratio of the hydrate to the background sediment for various frequencies from 1 Hz to 35 Hz. The largest signal comes from the 35 Hz data. Figure b (below) shows the electric eld versus source-receiver range for the corresponding frequencies. The electric elds fall off quickly at the higher frequencies due to stronger attenuation at the higher frequencies. (Available in full paper) Forward Modeling Numerical forward modeling studies were used to design the CSEM experiment. Radial mode electric fields were modeled using Flosadottir and Constable's (1996) forward modeling code. Our model consisted of a 105 m thick hydrate layer of 2 Ohm-m sandwiched between a background sediment of 1 Ohm-m at a 45 m depth in 1200 m of seawater (0.3 Ohm-m). We found that in order to detect the hydrate anomaly (the ratio of the responses of sediments containing hydrate to the background response of sediment only) we required relatively high frequencies of about 35 Hz (Figure 1a). However, frequencies above 10 Hz attenuate very quickly (Figure 1b).

Prediction of lithology distribution is critical for development of oilfield and is also one of the basic tasks of geological modeling. Stochastic simulation has been proved to be an effective method for simulation the distribution of lithology. While stochastic simulation technique is theoretically a mathematical method, the result of simulation will be strongly affected by many factors, such as the quantity, quality, and distribution of well data, and so on. In the area or oilfield with limited wells and insufficient data, the uncertainty of simulation result will be very high, and the reliability of the result will be very low. This result with high uncertainty and low reliability will lead to very poor prediction of sand and shale. Further, the reliability of the result of petrophysical modeling will be low. This article introduces a new method by using constraint condition with high quality to improve the simulation result of lithology distribution and decrease the uncertainty of simulation result. Stratigraphic forward modeling is an effective approach to simulate the process of deposition, and this approach can characterize the geometry and distribution of complex sedimentation. But the resolution of the simulation result of this approach is lower than the requirement of development stage of oilfield. Seismic inversion has been proved to be an effective way with high resolution to describe the distribution of lithology by using high-quality seismic data, while seismic inversion is difficult to reflect the geological process and pattern. The combination of these two methods can provide good constraint condition for stochastic simulation. By using the results of stratigraphic forward modeling and seismic inversion, we can build the trend models for different lithology. The trend models can be used in stochastic simulation, and the trend models can improve the result of stochastic simulation. This paper took A oilfield in Oriente Basin in Ecuador as an example to show the process of this method. We built the stratigraphic forward modeling model based on the geological understanding and completed the research of seismic inversion of M1 layer of Napo Formation. The result of serigraphic forward modeling and seismic inversion was resampled into the geological model. Based on these two results, the trend models of sand and shale of M1 layer have been completed. The trend models have been used to constrain the stochastic simulation of lithology with sequential indicator simulation algorithm. This method can effectively decrease the uncertainty of simulation result caused by insufficient well data and improve the reliability of lithological model which further improves the result of petrophysical modeling.

ABSTRACTThe semi‐airborne transient electromagnetic method is characterized by a large detection depth, high signal‐to‐noise ratio, fast acquisition rate, low cost, and ability to be used for exploration in scenarios with complex geological conditions. As a result, the semi‐airborne transient electromagnetic method has a great potential in the fields of mineral exploration, hydrological study and geohazard detection. However, most of the existing semi‐airborne transient electromagnetic data interpretation methods still rely on one‐dimensional forward modelling and inversion, which could lead to an incorrect geological interpretation. In this paper, we develop a three‐dimensional inversion for semi‐airborne transient electromagnetic data to recover a reliable subsurface conductivity distribution. The forward modelling is based on the effective vector finite element method with an unstructured tetrahedral mesh, which is capable of simulating complex geo‐electric structures and the topography. Through the numerical experiments of several three‐dimensional synthetic models, we study the influence of the number of excitation sources, flight mode and complex topography on the inversion results. The synthetic model studies reveal that: (1) by increasing the number of excitation sources, we can obtain a higher resolution conductivity image with less artefacts; (2) the detectability can be increased by flying along the terrain when the topography is complex; (3) the topography should be considered in the forward modelling and inversion to obtain a reasonable conductivity model using the semi‐airborne transient electromagnetic method; and (4) the three‐dimensional inversion still works when the inhomogeneity is present nearby the transmitter.

Note on: ‘EMLCLLER—A program for computing the EM response of a large loop source over a layered earth model’ by N.P. Singh and T. Mogi, Computers & Geosciences 29 (2003) 1301–1307

Hydrogeophysical exploration of three-dimensional salinity anomalies with the time-domain electromagnetic method (TDEM)

Onshore flow characteristics of the 1755 CE Lisbon tsunami: Linking forward and inverse numerical modeling

According to the basic rules and characteristics of the gold-polymetallic deposits of Beiya gold mine area in terms of mineralization and ore controlling, it is concluded that skarn deposit is the main ore deposit type in this area and the geological conditions are analyzed by the statistics of the physical parameters. Then, the tectonic, rocks, stratum, ore geophysical models have been treated by the forward modeling numerical simulation and the results are analyzed comprehensively. Based on the forward modeling results, combined with the relevant physical differences, the principle and exploration method test and research for the comprehensive geophysical exploration technology has been carried out, covering the induced polarization and magnetic prospecting for the ore body as well as the indirect geophysical exploration method by means of plane gravity data, audio-magnetotelluric sounding for rock mass and tectonics, the mineralization mode-physical forward modeling - geophysical exploration mode has been established and good results have been achieved. Therefore, a location forecast method has been put forward for the concealed skarn type Fe-Au deposit which is adaptive to the mineralized geological background of Beiya and other similar areas.

The widely differing interpretations of the function of certain artifactual materials associated with the shaft-tomb complex of western Mexico are utilized to illustrate certain problems in the analysis of nonhistoric archaeological materials thought to be of religious significance. It is suggested that in the absence of some new model specifically designed to deal with the religious sub-system of nonhistoric societies and in the absence of interpretative data derived from relatively secure historical contexts, the only approach which seems justified, in light of our present level of knowledge, is to operate on the level of broad generalized statements of probability.