The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Senescent and damaged mitochondria undergo selective mitophagic elimination through mechanisms requiring two Parkinson's disease factors, the mitochondrial kinase PINK1 (PTEN-induced putative kinase protein 1; PTEN is phosphatase and tensin homolog) and the cytosolic ubiquitin ligase Parkin. The nature of the PINK-Parkin interaction and the identity of key factors directing Parkin to damaged mitochondria are unknown. We show that the mitochondrial outer membrane guanosine triphosphatase mitofusin (Mfn) 2 mediates Parkin recruitment to damaged mitochondria. Parkin bound to Mfn2 in a PINK1-dependent manner; PINK1 phosphorylated Mfn2 and promoted its Parkin-mediated ubiqitination. Ablation of Mfn2 in mouse cardiac myocytes prevented depolarization-induced translocation of Parkin to the mitochondria and suppressed mitophagy. Accumulation of morphologically and functionally abnormal mitochondria induced respiratory dysfunction in Mfn2-deficient mouse embryonic fibroblasts and cardiomyocytes and in Parkin-deficient Drosophila heart tubes, causing dilated cardiomyopathy. Thus, Mfn2 functions as a mitochondrial receptor for Parkin and is required for quality control of cardiac mitochondria.

/pdf/pink1-phosphorylated-mitofusin-2-is-a-parkin-receptor-for-2cm6h874b2.pdf

PINK1- Phosphorylated Mitofusin 2 is a Parkin Receptor for Culling Damaged Mitochondria

Simulated global changes, including warming, increased precipitation, and nitrogen deposition, alone and in concert, increased net primary production (NPP) in the third year of ecosystem-scale manipulations in a California annual grassland. Elevated carbon dioxide also increased NPP, but only as a single-factor treatment. Across all multifactor manipulations, elevated carbon dioxide suppressed root allocation, decreasing the positive effects of increased temperature, precipitation, and nitrogen deposition on NPP. The NPP responses to interacting global changes differed greatly from simple combinations of single-factor responses. These findings indicate the importance of a multifactor experimental approach to understanding ecosystem responses to global change.

https://science.sciencemag.org/content/sci/298/5600/1987.full.pdf

Grassland responses to global environmental changes suppressed by elevated CO2.

Stable Isotope Analysis: A Tool for Studying Past Diet, Demography, and Life History

1. Chinese archaeology: past, present, and future 2. Environment and ecology 3. Foragers and collectors in the Pleistocene-Holocene transition (24,000-9000 cal. BP) 4. Domestication of plants and animals 5. Neolithization: sedentism and food production in the Early Neolithic (7000-5000 BC) 6. Emergence of social inequality: the Middle Neolithic (5000-3000 BC) 7. Rise and fall of early complex societies: the Late Neolithic (3000-2000 BC) 8. Formation of early states in the Central Plain: Erlitou and Erligang (1900/1800-1250 BC) 9. Bronze cultures of the north frontiers and beyond during the early second millennium BC 10. The Late Shang dynasty and its neighbors (1250-1046 BC) 11. Chinese civilization in comparative perspective.

The Archaeology of China: From The Late Paleolithic To The Early Bronze Age

Introduction Explanations of the origins of institutionalized social inequality and political privilege must resolve the central paradox of political life – why people cooperate with their own subordination and exploitation in noncoercive circumstances (Godelier 1986:13). In the following pages we address this paradox for an archaeological case from Mesoamerica. The first chiefdoms in lowland Mesoamerica, the focus of this discussion, appear to have developed some 3300 years ago among the Mokaya in the Mazatan region of Chiapas, Mexico, during the first part of the Early Formative, 1550–1150 BC (all dates are in radiocarbon years). This period also witnessed the adoption of maize agriculture in the coastal lowlands, the founding of sedentary villages, the adoption of ceramic technology, a rapid population increase, and the beginnings of patronized craft specialization. To explain these developments, we first offer a general model for the development of hereditary rank distinctions as the outcome of competition among political actors vying for prestige and social esteem. We then apply this model to the issues of technological and demographic change in the development of social inequality in the Mazatan region. Resources, prestige and privilege It is difficult to imagine why people would voluntarily submit to non-egalitarian political systems. Despite this perception, the institutionalization of political privilege may have been quite simple; it may at first have been in people's best interest. Nowadays, in addressing this issue, we are hindered by hindsight and evolutionist and functionalist thinking that regards change as reaction to existing social problems.

Factional competition and political development in the New World: The power of prestige: competitive generosity and the emergence of rank societies in lowland Mesoamerica

This handsome volume presents the creations of Mesoamerica's most ancient societies in their archaeological contexts The Olmec, who are best known for a unique style of monumental stone head and jade were-jaguar, were based along the Gulf of Mexico, but evidence of their influence has been found throughout Mesoamerica Recent spectacular finds, including wooden Olmec busts, jade celts, and rubber balls, are discussed and placed within the context of settlement patterns, religious practices, and ritual from 1800 to 500 BCE The study provides a framework for understanding Olmec art and archaeology as well as the history of how this important and enigmatic precursor to other Mesoamerican civilizations such as the Maya and Aztec came to be uncovered

Olmec art and archaeology in Mesoamerica

SOUTHALL, AIDAN W. i952. Lineage formation among the Luo. International African Institute Memorandum 26. . I989. \"Power, sanctity, and symbolism in the political economy of the Nilotes,\" in The creativity of power. Edited by W. Arens and I. Karp, pp. i83-222. Washington, D.C.: Smithsonian Institution Press. WHEATLEY, PAUL. I97I. The pivot of the four quarters: A preliminary enquiry into the origins and character of the ancient Chinese city. Chicago: Aldine.

Prehistoric Subsistence in the Soconusco Region

During the last four decades, mesoamerican archaeologists regularly have employed various chemical assay techniques to determine the geological sources of obsidian artifacts. In recent years, the reliability of these analytical procedures has increased and their costs have declined, encouraging the assay of ever larger samples. Nonetheless, several constraints make it unlikely that compositional data will be used routinely to attribute entire collections to their geological sources. This report describes a test of visual sourcing, a technique that for many sites in the Maya region is only slightly less accurate than compositional assay. We also propose sampling strategies that combine visual and compositional sourcing in ways that allow large collections to be accurately sourced at low costs. Finally, we suggest ways to develop the technique for use throughout Latin America.

Determining the Geological Provenance of Obsidian Artifacts from the Maya Region: A Test of the Efficacy of Visual Sourcing

Archaeological excavations carried out during the past five years along the Pacific coast of Mexico, Guatemala, and El Salvador have recovered 79 new 14C dates for the Late Archaic and Early to Middle Formative periods. We analyze these new dates along with 25 previously published dates to refine a sequence of 10 archaeological phases spanning almost three and a half millennia, from ca. 4000 to 650 B.C. The phases are summarized with a brief description of their most salient characteristics. We include illustrations of the Early Formative period ceramics and figurines from the Mazatan region. The sequence of phases reveals a trajectory of cultural evolution beginning in the Archaic period with the mobile hunting, fishing, and gathering Chantuto people. By 1550 B.C., the first ceramic-using sedentary communities appeared on the coast of Chiapas. They were hunter-fisher-gatherers who supplemented their food supply with cultivated plants, including maize and beans. We suggest that by the Locona phase (1400–1250 B.C.) in Chiapas, they began the transition from egalitarian sociopolitical organization to simple chiefdoms, leaving behind evidence of large-scale architectural constructions, long-distance imports such as obsidian and jade, and elaborately crafted prestige goods. Also in Chiapas, during the Cherla phase (1100–1000 B.C.), ceramic and figurine styles, nearly identical to those found at San Lorenzo Tenochtitlan on the Gulf Coast, made their first appearance. Many of the local artifact styles were gradually replaced by styles that became increasingly widespread in Mesoamerica. The chronology presented here shows that these changes were roughly contemporaneous with similar ones in neighboring regions of Mesoamerica.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0956536100002169

John E. Clark

Papers

Factional competition and political development in the New World: The power of prestige: competitive generosity and the emergence of rank societies in lowland Mesoamerica

Olmec art and archaeology in Mesoamerica

Prehistoric Subsistence in the Soconusco Region

Determining the Geological Provenance of Obsidian Artifacts from the Maya Region: A Test of the Efficacy of Visual Sourcing

Radiocarbon Chronology for the Late Archaic and Formative Periods on the Pacific Coast of Southeastern Mesoamerica