To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
La Commission de vérité et réconciliation du Canada (CVRC) réitérait en 2015 la volonté des Peuples Autochtones de renouveler leur relation avec l’État canadien. Cet article présente une réflexion théorique sur les possibilités offertes par le fédéralisme afin de renouveler cette relation entre les Autochtones et l’État. L'article confronte les arguments des tenants du fédéralisme comme cadre des relations entre les Autochtones et l’État et ceux des critiques de l’établissement d'un rapport fédéral de nation à nation entre les Peuples Autochtones et le Canada. L'article présente donc une proposition pour le renouvellement de la relation entre les Autochtones et l’État à travers un modèle de fédéralisme basé autour de régions autochtones autonomes.
The distinction between what I call nonelective obligations and discretionary obligations, a distinction that focuses on one particular thread of the distinction between perfect and imperfect duties, helps us to identify the obligations that carry over from principals to agents. Clarity on this issue is necessary to identify the moral obligations within “shareholder primacy” (i.e., “shareholder theory”), which conceives of managers as agents of shareholders. My main claim is that the principal-agent relation requires agents to fulfill nonelective obligations, but it does not always require (and sometimes actually prohibits) discharging discretionary obligations. I show that the requirement to fulfill nonelective obligations is more far-reaching than has been acknowledged by most defenders and critics of shareholder primacy. But I also show that managers are not bound by certain discretionary obligations like charity, showing that their moral obligations are more circumscribed than the obligations that apply to human beings in general.
Path planning represents planning collision-free strategies to move from starting point to ending point. These strategies can be carried out for known and unknown environments. Recently, a novel and reduced CPU-time modeling and simulation methodology for path planning in known environment based on resistive grids (RGs) has been introduced. In this work, a novel modified version of Resistive Grid Path Planning Methodology (RGPPM) methodology is presented with the purpose of exploring collision-free path planning for robotic arms. This extension of the methodology allows to numerically relate positions in the RG with angular values of the robotic systems. In addition, it is possible to include obstacles in the configuration space, and therefore collision detection can be established for RGs. Finally, the variation of links for robotic arms and obstacles for configuration space is explored by simulating different scenarios.
The Formative-period site of Altica in the Patlachique Range poses many methodological problems when designing an excavation strategy. Three millennia of erosion, twentieth-century chisel plowing, and modern reforestation efforts have destroyed or disturbed most surface architecture above the local tepetate bedrock. As such, in the early stages of the Altica Project, the primary concern was the detection and identification of subsurface features, especially deep pits as found at other Formative sites. Although Altica is located at the top of a low, flat ridge, strong localized rain frequently flooded the terraces of interest for days, making it impossible to detect subsurface features using the most common prospection techniques. Because of these practical and taphonomic limitations, we relied on magnetic gradient prospection. This technique had never been applied to an early village site in the Basin of Mexico. This paper presents the methods used, discusses various difficulties encountered during prospection, applies interprets the results of the magnetic gradient study using results from excavation and aerial multispectral remote sensing. We discuss how the method might be applied to similar Formative sites to remotely detect indicators of anthropogenic activity, including subsurface features.
Rhinoptera steindachneri is a commercially important, medium-sized, pelagic migratory batoid fish with benthic feeding habits. It has been considered a specialized predator that feeds on molluscs as well as benthic ophiurids and arthropods off the Mexican Pacific coast. Most biological aspects of this species in La Paz Bay are unknown, despite its being a commercially important species of conservation interest. Therefore, the aim of this study was to characterize the feeding habits of R. steindachneri based on specimens caught in artisanal fisheries. The stomach contents of 310 specimens (146 females and 164 males) were analysed, all captured from 2013 to 2015. The vacuity index was 97.1%, and the most important prey species were Mysidium spp. and Cylichna spp. Because of the high frequency of empty stomachs recorded, it was not possible to describe with precision the general diet of the species. Three hypotheses were developed to try to explain why this characteristic occurred in this species, ranging from eating habits to physiology and prey digestion and geographic location of the study. However, considering the mechanical process of prey handling of R. steindachneri, several hypotheses were formulated, with the hour of capture, chemical processes and physiology and prey digestion being the most probable to explain this high vacuity index reported in this study.
People with serious mental illness (SMI) have high rates of smoking and need better access to cessation treatment. Mobile behavioral interventions for cessation have been effective for the general population, but are not usable by many with SMI due to cognitive impairments or severe symptoms. We developed a tailored mobile cessation treatment intervention with features to reduce cognitive load.
We enrolled 20 smokers with SMI and showed them how to use the program on a device of their choice. They were assessed at 8 weeks for intervention use, usability, satisfaction, smoking characteristics, and biologically verified abstinence.
Participants accessed an average of 23.6 intervention sessions (SD = 17.05; range 1–48; median = 17.5) for an average total of 231.64 minutes (SD = 227.13; range 4.89–955.21; median = 158.18). For 87% of the sessions, average satisfaction scores were 3 or greater on a scale of 1–4. Regarding smoking, 25% of participants had reduced their smoking and 10% had biologically verified abstinence from smoking at 8 weeks.
Home and community use of this mobile cessation intervention was feasible among smokers with SMI. Further research is needed to evaluate such scalable approaches to increase access to behavioral treatment for this group.
Estudios geofísicos, técnicas de sensores remotos y realización de mapas topográficos con GPS diferencial y vehículos aéreos no tripulados (VANT) han proporcionado una mejor comprensión de la organización espacial de los conjuntos departamentales y barrios en Teotihuacán. Nuestras investigaciones demuestran que en contraste con el mapa producido por el Teotihuacan Mapping Project (TMP) (Millon et al. 1973), el distrito de Tlanjinga es más rectangular y está más formalmente organizado, mientras que los conjuntos individuales tienen formas más irregulares, como lo había mostrado la excavación de Tlajinga 33 (Widmer y Storey 1993). Esto difiere de los nítidos cuadrados y rectángulos interpretados por las reconstrucciones arquitectónicas del TMP. El estudio de las imágenes satelitales mostró manchas blanquecinas en el terreno que parecen corresponder con áreas elevadas del mismo y con la desintegración de los aplanados de cal, destruidos por el tiempo y el trabajo agrícola. También verificamos la continuación del trazo de la Calzada de los Muertos que cruza este distrito mediante la modificación del relieve ocasionada por la excavación realizada en la toba volcánica subyacente (tepetate).
Teotihuacan's Tlajinga district is a cluster of neighborhoods on the southern periphery of the city best known for earlier investigations at Compound 33:S3W1. New research includes excavations at two other apartment compounds and along the southern extension of the Street of the Dead. Excavation contexts, major finds, chronology, and preliminary interpretations are the subject of this article. We highlight evidence attesting to a major obsidian-blade workshop at Compound 17:S3E1, offerings, and other features at that compound and Compound 18:S3E1, and the tempo and processes of urbanization viewed through well-recorded stratigraphic sequences of the compounds and the Street of the Dead. We conclude that significant occupation began in the Miccaotli phase, but it was not until some point in the Early Tlamimilolpa phase that the dominant housing type became apartment compounds; the continuation of the axis of Street of the Dead in the district was accomplished by excavating in the volcanic tuft substrate (tepetate) and could have been undertaken by the inhabitants of the district themselves; and the presence of items such as a sculpted stone face, marine shell, and polychrome pottery demonstrates that commoners at Teotihuacan enjoyed some access to finer items within the interregional economy.
OBJECTIVES/SPECIFIC AIMS: High-grade serous ovarian carcinoma (HGSOC) is the most common and malignant histological subtype of epithelial ovarian cancer. While the majority of HGSOC patients initially respond to platinum-based chemotherapy, they often present with recurrent chemoresistant disease, which is extremely fatal. Therefore, there is an urgent need to identify predictive biomarkers of platinum response and to develop rational, targeted therapies to improve the outcome of patients with HGSOC. The objectives of the present study are to profile and assess the clinical significance of MYC network dysregulation in HGSOC. METHODS/STUDY POPULATION: We will conduct a retrospective cohort study of Puerto Rican Hispanics with HGSOC who underwent surgery followed by platinum-based chemotherapy at clinical institutions in Puerto Rico. Medical records, pathology reports, and cancer registries will be reviewed to extract data on clinicopathological features, disease recurrence, and death. For eligible patients, formalin-fixed, paraffin-embedded (FFPE) tissue samples will be processed and analyzed by quantitative Real Time PCR (qRT-PCR) and immunohistochemistry (IHC). RESULTS/ANTICIPATED RESULTS: Expression levels of MYC and MYC-related molecules are expected to correlate with clinicopathological features and prognosis of HGSOC. DISCUSSION/SIGNIFICANCE OF IMPACT: The identification and validation of clinically-relevant alterations in HGSOC, such as dysregulation of the MYC network, will be crucial to guide therapy regimen, maximize clinical benefit, and improve patient outcome.
Low density (LD) steels have shown particular characteristics in terms of mechanical properties and microstructure, since they have high strength, high ductility and density reduction up to 18%. On the other hand, the addition of microalloying elements such as Ti and B generate hardening by solid solution and precipitation, as well as grain refinement effect. LD steels generate nano-sized kappa phase precipitated from the austenite matrix, and these advanced steels can reach strength and elongation up to 780 MPa and 60%, respectively. The main objective of this research work is the metallographic, structural and mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in metallic mold. LD-Ti/B steel samples were homogenized at 1100 °C during 20, 50, 100, 150 and 200 minutes followed by water quenching. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers testing (HV10), respectively. In general, results showed a typical dendritic microstructure with average grain size of 1256 μm in the as-cast condition. On the other hand, the as-homogenized condition showed an austenitic equiaxial microstructure with average grain size from 164 to 940 μm. Austenite, ferrite and kappa phases were detected by X-ray diffraction (XRD). Also, second-phase particles such as AlN, TiC and MnS were detected by LOM and SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the as-homogenized condition microhardness gradually decreases from 223 to 198 HV10 as holding time increases.
The welding heat input has been pointed out as a main limiting factor for TWinnig Induced Plasticity (TWIP) steel weldability. Scarce research works have been focused on the study of application and effects of the Gas Tungsten Arc Welding (GTAW) process in the TWIP steel, especially in higher thickness plate. In this research work was conducted a detailed analysis of a butt weld joint performed in plates of TWIP steel microalloyed with titanium (TWIP-Ti) of 6.3 mm thickness. The autogenous GTAW process with low heat input was applied. The analysis considered grain size measurements, second phases identification, post-weld mechanical properties (microhardness) and the welding thermal field. A Finite Element Model (FEM), validated through experimental results, allowed correlating metallurgical results with the thermal field. Likewise, the phases prediction carried out by means of JMatPro 9.0 software during solidification process as well as the estimation of particle precipitation were in good agreement with the experimental results. These predictive diagrams were calculated taking into account the TWIP-Ti steel chemical composition, the grain size measured in critical weld regions and experimental cooling rates. The low heat input improved the microstructural conditions in the heat affected zone (HAZ) whose average grain size and precipitate particles, like (C, N)Ti, promoted good mechanical properties as compared to the base material (as-solution condition). Some particles like Al2O3 y MnS produced microporosities in the HAZ. Despite this, the weld joint did not present hot cracking in the FZ-HAZ interface.
Recently, low-density steels have received increased attention as promising alternatives for automotive applications of the next generation of Advanced High-Strength Steels (AHSS), considering that vehicle´s weight decrease has been the subject of intense interest. It is well-known that the addition of rare earth metals (REM) has a remarkable effect on shape control and the modification of inclusions. Also, REM additions affect the grain size refinement as well as the tendency to form oxides and sulfides. The aim of this research work was to determine the effect of REM (Ce, La) addition on the microstructure and mechanical properties of the Fe-30Mn-8Al-1.8C low-density steel in as-cast condition. In order to clarify the REM effect on the Fe-Mn-Al-C system, non-microalloyed (LD-NM) and REM microalloyed (LD-REM) specimens were examined in detail by means of light optical and scanning electron microscopy for microstructural characterization. In the same way, the primary and secondary phases founded in the studied steels were identified by X-ray diffraction (XRD). Meanwhile, in order to evaluate the mechanical properties, ten microhardness measurements were carried out on the overall bulk by the Vickers hardness testing. In general, the results showed a dendritic refinement effect due to the addition of REM to low-density steel. REM acted as effective inoculants agents which reduced the primary and secondary arm spacing. Also, the strong segregation tendency at the grain boundaries in the liquid phase was limited. XRD profiles revealed the presence of austenite, ferrite, κ and DO3 phases. Low density steel microalloyed with REM showed a moderate increase in hardness compared to the non-microalloyed steel in the as-cast condition.
The Colombian Constitutional Court (Court) ordered the Colombian government to seek the restitution of a set of 122 golden objects of the Quimbaya people in a judgment issued on October 19, 2017 (Judgment). The Judgment addressed significant issues of international law relating to unilateral acts, treaty interpretation, cultural property (particularly that of indigenous peoples), and the settlement of disputes involving claims for restitution of cultural property through diplomacy and mediation.
High-Mn Twinning Induced Plasticity (TWIP) steels are an excellent alternative in the design of structural components for the automotive industry. The TWIP steels application allows weight reduction, maintaining the performance of vehicles. Nowadays the research works focused on TWIP steel weldability are relative scarce. It is well-known that weldability is one of the main limitations for industrial application of TWIP steel. The main goal of this research work was studied the effect of heat input on the microstructural changes generated in a TWIP steel microalloyed with Ti. A pair of welds were performed through Gas Tungsten Arc Welding (GTAW) process. The GTAW process was carried out without filler material, using Direc Current Electrode Negative (DCEN), tungsten electrode EWTh-2 and Ar as shielding gas. The microstructure and average grain size in the fusion (FZ) and heat affected zone (HAZ) were determined by light optical metallography (LOM). Elements segregation in the FZ was evaluated using point and elemental mapping chemical analysis (EPMA) by Scanning Electron Microscopy and Electron Dispersive Spectroscopy (SEM-EDS). Phase transformations were evaluated using X-ray diffraction (XRD). Finally, the hardness were measured by means of Vickers microhardness testing (HV500). The results show that the FZ is characterized by a dendritic solidification pattern. Meanwhile, the HAZ presented equiaxed grains in both weld joints. On the other hand, the TWIP-Ti steel weldments did not present austenite phase transformations. Nevertheless, the FZ exhibited variations in the chemical elements distribution (Mn, Al, Si and C), which were higher as the heat input increases. Finally, the heat input reduced the microhardness of TWIP-Ti steel weld joints. Although post-welding hardness recovery was detected, which is associated with precipitation of Ti second-phase particles.
Rosin resin is constituted by rosin acids, in particular, abietic acid, which is an inexpensive substance. This paper concerns the study of the molecular interactions between a bifunctional monomer of abietic acid with isocyanate to form polyurethane. Polyurethane is a varnish that can be applied to any timber surface protecting it from chemical and environmental factors. Furthermore, the polar groups (OH´s) of the diol have a direction along the molecular axis thus, increasing their intermolecular interactions with the isocyanate groups. The varnish named as (PAR), was synthesized in the laboratory and applied to a timber surface whereby its functionality was evaluated. Morphological and spectroscopic studies were carried out on the diol obtained and the polyurethane. Likewise, we behaved several of physical and chemical analyses of vanish. The comparative SEM showed a homogeneous phase on the PAR surface and FTIR between the diphenylmethane, 4-4, diisocyanate (MDI) and the varnish from hydroxylated rosin resin (HAA) showed that the reaction was carried out in its entirety, exhausting the limiting reagent (MDI). The obtained varnish which was labelled as PAR has very suitable characteristics for indoor use. It has a transparent and bright appearance, a solids percentage of 44-45%, a drying time for application between layers and layers of 15-20 minutes.
Most archaeological practice involves horizontal excavations of ancient occupations and cemeteries, but the Chachapoya of Peru's eastern montane built tombs along narrow cliff ledges, which require innovative methods of investigation. Many of these sites are becoming exposed and threatened due to increased deforestation. The La Petaca mortuary complex includes 125 constructed platforms, modified ledges, mausoleums, and caves containing human remains across one section of an exposed rock face approximately 200 m across by approximately 80 m high. While the site has been looted and damaged due to various taphonomic processes (including ecological, geological, and cultural), we argue that there are recoverable details, especially in relation to how the ancient Chachapoya people created and accessed these vertical spaces. Through collaboration with technical professionals, we identified and documented many tombs using vertical progression techniques. This valuable partnership between spelunkers and archaeologists allowed us to develop techniques for “vertical archaeology,” including safe access in order to be able to document, sample, and make detailed observations of building methods and burial contents.