scholarly journals Aspectos de la historia de la vegetación de México con base en macrofósiles de angiospermas

2017 ◽  
pp. 99
Author(s):  
Sergio R.S. Cevallos-Ferriz ◽  
Alicia Silva-Pineda

The history of Mexican vegetation is mainly known through extrapolations based on its extant flora and/or paleobotanical work done in other countries. While macrofossils corroborate that in the past, as in the present, the Mexican flora had relationships with those of other areas, its study reveals that during the Cretaceous it had affinities with the boreal floras, though, some of the d escribed plants have close phylogenetic relationships with plants now growing naturally in the southern hemisphere. During the Tertiary the relationship with the boreal floras continued, suggesting that if some taxa originated in Gondwana, at least some of their genera and species could differentiate and radiate in the northern hemisphere, as suggested by some Anacardiaceae and perhaps other Leguminosae. A legume, Lysiloma, suggest that endemic taxa that characterize the extant Mexican vegetation have a long history, since they are known from Oligocene sediments. Another plant of the same family, Reinweberia, also suggest that during the Tertiary there were endemic plants that became extinct, and underscores the fact that for a long time the Mexican vegetation have had a distinct composition. The macrofossils of angiosperms suggest that only recently, perhaps no more than 10 million years ago, the vegetation types recognized today were established, although, those of the past could be similar.

Author(s):  
Claudia Lambrugo

This chapter addresses three interconnected topics, beginning with a short overview of the archaeology of children and childhood in Italy, explaining how and why the Italian contribution to the topic has been very recent. The chapter then moves on to explore the relationship between modern children, Italian scholars of ancient history of art and archaeology, and museums; it notes that for a very long time Italian universities and museums have not been interested in developing didactic archaeology at all, especially when the spectators were children, whether of pre-school or older age. Finally, returning to children in the past, two noteworthy case studies of the presentation of ancient children at exhibitions are illustrated as an interesting point of convergence between current archaeological studies in Italy on childhood in the ancient world, and the newly generated need to communicate to the general public the result of research works.


2008 ◽  
Vol 67 (1) ◽  
pp. 47-54
Author(s):  
Chantal Kesteloot

De geschiedenis van de Vlaamse beweging wekt sinds lang de belangstelling van de Vlaamse vorsers. Tegelijk heeft de theorievorming rond nationalisme zich tijdens de laatste jaren volledig vernieuwd. De Gentse historicus Maarten van Ginderachter combineert in Le chant du coq zijn twee interessesferen en stelt een bijtend essay voor over de geschiedenis van de Waalse beweging. Het betreft een boeiende herlezing van de meest recente werken die aan de beweging gewijd werden, in het bijzonder L’Encyclopédie du Mouvement wallon. Zijn doel is aan te tonen dat, in weerwil van de steeds herhaalde visie, de beweging eveneens een etnisch discours gebruikt. Bijgevolg is de tegenstelling tussen een 'etnische' Vlaamse beweging en een 'civiele' Waalse beweging eerder een geloofszaak die niet bestand is tegen een wetenschappelijke analyse. De vraagstelling verdient een verder uitdieping. Om de staat van de geschiedschrijving van de Waalse beweging te begrijpen, is het essentieel de omstandigheden van de productie te bekijken net als de verhouding, in Wallonië, tussen de politieke macht en de academische sfeer. Daarenboven stelt zich de vraag naar de (on)mogelijkheid van een gedeelde nationale geschiedenis. Vlaamse en franstalige vorsers lijken meer en meer een verschillende visie op het verleden te hebben, een visie die zelfs zodanig verschilt dat er geraakt wordt aan het zelfbeeld en het beeld van de andere.________Le chant du coqFlemish researchers have been interested in the history of the Flemish movement for a long time. At the same time the theory formation about nationalism has been completely renovated during the past years. In Le chant du coq the Ghent historian Maarten Van Ginderachter combines his two areas of interest and presents a sarcastic essay about the history of the Walloon movement. It concerns an absorbing rereading of the most recent works that were dedicated to the movement, in particular the Encyclopédie du Mouvement wallon. He intends to demonstrate that in spite of the ever repeated vision, the movement also utilizes an ethnic discourse. Consequently the opposition between an 'ethnic' Flemish movement and a 'civil' Walloon movement is rather a matter of faith, which cannot stand up to scientific analysis. The issue deserves further in-depth study. In order to understand the state of the historiography of the Walloon movement, it is essential to view the circumstances of the production as well as the relationship between the political power and the academic atmosphere in Wallonia. In addition the question about the (in)possibility of a shared national history must be raised. The visions of the past held by Flemish and French-speaking researchers appear to be growing further and further apart, with the consequence that these separate visions influence both the self-image and the image of the other party.


Author(s):  
Will Kynes

This chapter introduces the volume by arguing that the study of biblical wisdom is in the midst of a potential paradigm shift, as interpreters are beginning to reconsider the relationship between the concept of wisdom in the Bible and the category Wisdom Literature. This offers an opportunity to explore how the two have been related in the past, in the history of Jewish and Christian interpretation, how they are connected in the present, as three competing primary approaches to Wisdom study have developed, and how they could be treated in the future, as new possibilities for understanding wisdom with insight from before and beyond the development of the Wisdom Literature category are emerging.


2021 ◽  
Author(s):  
Bárbara Moguel ◽  
Liseth Pérez ◽  
Luis David Alcaraz ◽  
Socorro Lozano-García ◽  
Luis Herrera-Estrella ◽  
...  

<p>For decades, paleoecological studies in lake sediments have focused on reconstructing the environments of the past and explaining phenomena linked to climatic variations. Recent advances in high-throughput DNA sequencing have allowed access to environmental DNA (eDNA) and ancient sedimentary DNA (sedaDNA) as a new and efficient proxy for past and present biodiversity. The basin of Mexico (BM) is located in the central part of the Trans-Mexican Volcanic Belt at 2,200 m a.s.l.; with the southern portion harboring the Chalco sub-basin. Lake Chalco is one of the last remaining natural aquatic ecosystems within the ever-expanding urban area surrounding Mexico City. The paleoenvironmental history of this lake has been previously characterized using sedimentological and geochemical proxies, as well as preserved microfossils (diatoms, pollen) with a temporal framework based on multiple radiocarbon dates. However, information for the remaining taxonomic groups and metabolic pathways remained unexplored. Here, we present the first metagenomics-based study for the Holocene in a high-altitude lake in Central Mexico –Lake Chalco. We explored the relationship between the lake’s paleoenvironmental condition and estimations of taxonomic and metabolic profiles across the sedimentary sequence (2.5 meters long). Multiple biological and abiotic variables revealed three main environmental phases: 1) a cool freshwater lake (FW1: 11,500-11,000 cal years BP), 2) a warm hyposaline lake (HS2: 11,000-6,000 cal years BP), and 3) a temperate, subsaline lake (SS3, <6,000 cal years BP). We describe the structure of the microbiota community and taxonomy richness turnover in the three Holocene paleoenvironmental phases. During the past 12 000 years BP the most abundant domains in Lake Chalco sediments were Bacteria, followed by Archaea, and Eukarya (36,722 genera). The analysis of functional proteins showed high biodiversity with a total of 27,636,243 proteins identified, but it was only possible to annotate 3,227,398 of them. Also, we identified several genes associated with some relevant pathways, such as methanogenesis. Altogether, this study allowed us to reconstruct the natural history of lake Chalco and its surroundings.</p>


Author(s):  
Timothy Cooper

This article explores embodied encounters with the Sea Empress oil spill of 1996 and their representation in oral narratives. Through a close reading of the personal testimonies collected in the Sea Empress Project archive, I examine the relationship between intense sensory experiences of environmental change and everyday interpretations of the disaster and its legacy. The art­icle first outlines the ways in which this collection of voices reveals sensory memories, embodied affects and narrative choices to be deeply entwined in oral representations of the spill, disclosing a ‘sensory event’ that created a powerful awareness of both environmental surroundings and their relationship to everyday social processes. Then, reading these narratives against-the-grain, I argue that narrators’ accounts tell a paradoxical story of a disaster that most now wish to forget, and reveal an ambivalent legacy of environmental change that is similarly consigned to the past. Finally, I relate this social forgetting of the Sea Empress to the wider history of environmental consciousness in modern Britain.


Author(s):  
Mary Ziegler

This article illuminates potential obstacles facing the reproductive justice movement and the way those obstacles might be overcome. Since 2010, reproductive justice—an agenda that fuses access to reproductive health services and demands for social justice—has energized feminist scholars and activists and captured broader public attention. Abortion rights advocates in the past dismissed reproductive justice claims as risky and unlikely to appeal to a broad enough audience. These obstacles are not as daunting as they first appear. Reframing the abortion right as a matter of women’s equality may eliminate some of the constitutional hurdles facing a reproductive justice approach. The political obstacles may be just as surmountable. Understanding the history of the constitutional discourse concerning reproductive justice and reproductive rights may allow us to move beyond the impasse that has defined the relationship between the two for too long.


2021 ◽  
Author(s):  
◽  
Suze Wilson

<p>We have come to live in an age where leadership is the solution, regardless of the problem. Today, managers are called on to provide leadership which is ‘visionary’, ‘charismatic’, ‘transformational’ and ‘authentic’ in nature. This is what ‘followers’ are said to need to perform to their potential. The efforts of the academy in promoting these ideas means they are typically understood as modern, enlightened and grounded in scientific research. Taking a critical step back, this study examines why we have come to understand leadership in this way.  Adopting a Foucauldian methodology, the study comprises three case studies which examine Classical Greek, 16th century European and modern scholarly discourses on leadership. The analysis foregrounds change and continuity in leadership thought and examines the underpinning assumptions, problematizations and processes of formation which gave rise to these truth claims. The relationship and subjectivity effects produced by these discourses along with their wider social function are also considered.  What the study reveals is that our current understanding of leadership is not grounded in an approach more enlightened and truthful than anything that has come before. Rather, just as at other times in the past, it is contemporary problematizations, politically-informed processes of formation and the epistemological and methodological preferences of our age which profoundly shape what is understood to constitute the truth about leadership.  Through showing how leadership has been thought of at different points in time, this thesis argues that far from being a stable enduring fact of human nature now revealed to us by modern science, as is typically assumed, leadership is most usefully understood as an unstable social invention, morphing in form, function and effect in response to changing norms, values and circumstances. Consistent with this understanding, a new approach to theory-building for organizational leadership studies is offered. This study shows, then, why we ought to think differently about leadership and offers a means by which this can occur.</p>


2021 ◽  
Author(s):  
◽  
Suze Wilson

<p>We have come to live in an age where leadership is the solution, regardless of the problem. Today, managers are called on to provide leadership which is ‘visionary’, ‘charismatic’, ‘transformational’ and ‘authentic’ in nature. This is what ‘followers’ are said to need to perform to their potential. The efforts of the academy in promoting these ideas means they are typically understood as modern, enlightened and grounded in scientific research. Taking a critical step back, this study examines why we have come to understand leadership in this way.  Adopting a Foucauldian methodology, the study comprises three case studies which examine Classical Greek, 16th century European and modern scholarly discourses on leadership. The analysis foregrounds change and continuity in leadership thought and examines the underpinning assumptions, problematizations and processes of formation which gave rise to these truth claims. The relationship and subjectivity effects produced by these discourses along with their wider social function are also considered.  What the study reveals is that our current understanding of leadership is not grounded in an approach more enlightened and truthful than anything that has come before. Rather, just as at other times in the past, it is contemporary problematizations, politically-informed processes of formation and the epistemological and methodological preferences of our age which profoundly shape what is understood to constitute the truth about leadership.  Through showing how leadership has been thought of at different points in time, this thesis argues that far from being a stable enduring fact of human nature now revealed to us by modern science, as is typically assumed, leadership is most usefully understood as an unstable social invention, morphing in form, function and effect in response to changing norms, values and circumstances. Consistent with this understanding, a new approach to theory-building for organizational leadership studies is offered. This study shows, then, why we ought to think differently about leadership and offers a means by which this can occur.</p>


Author(s):  
John J. W. Rogers ◽  
M. Santosh

Pangea, the most recent supercontinent, attained its condition of maximum packing at ~250 Ma. At this time, it consisted of a northern part, Laurasia, and a southern part, Gondwana. Gondwana contained the southern continents—South America, Africa, India, Madagascar, Australia, and Antarctica. It had become a coherent supercontinent at ~500 Ma and accreted to Pangea largely as a single block. Laurasia consisted of the northern continents—North America, Greenland, Europe, and northern Asia. It accreted during the Late Paleozoic and became a supercontinent when fusion of these continental blocks with Gondwana occurred near the end of the Paleozoic. The configuration of Pangea, including Gondwana, can be determined accurately by tracing the patterns of magnetic stripes in the oceans that opened within it (chapters 1 and 9). The history of accretion of Laurasia is also well known, but the development of Gondwana is highly controversial. Gondwana was clearly a single supercontinent by ~500 Ma, but whether it formed by fusion of a few large blocks or the assembly of numerous small blocks is uncertain. Figure 8.1 shows Gondwana divided into East and West parts, but the boundary between them is highly controversial (see below). We start this chapter by investigating the history of Gondwana, using appendix SI to describe detailed histories of orogenic belts of Pan-African age (600–500-Ma). Then we continue with the development of Pangea, including the Paleozoic orogenic belts that led to its development. The next section summarizes the paleomagnetically determined movement of blocks from the accretion of Gondwana until the assembly of Pangea, and the last section discusses the differences between Gondwana and Laurasia in Pangea. The patterns of dispersal and development of modern oceans are left to chapter 9, and the histories of continents following dispersal to chapter 10. By the later part of the 1800s, geologists working in the southern hemisphere realized that the Paleozoic fossils that occurred there were very different from those in the northern hemisphere. They found similar fossils in South America, Africa, Madagascar, India, and Australia, and in 1913 they added Antarctica when identical specimens were found by the Scott expedition.


2020 ◽  
pp. 1-13 ◽  
Author(s):  
Kornelia Kończal

In early 2018, the Polish parliament adopted controversial legislation criminalising assertions regarding the complicity of the ‘Polish Nation’ and the ‘Polish State’ in the Holocaust. The so-called Polish Holocaust Law provoked not only a heated debate in Poland, but also serious international tensions. As a result, it was amended only five months after its adoption. The reason why it is worth taking a closer look at the socio-cultural foundations and political functions of the short-lived legislation is twofold. Empirically, the short history of the Law reveals a great deal about the long-term role of Jews in the Polish collective memory as an unmatched Significant Other. Conceptually, the short life of the Law, along with its afterlife, helps capture poll-driven, manifestly moralistic and anti-pluralist imaginings of the past, which I refer to as ‘mnemonic populism’. By exploring the relationship between popular and political images of the past in contemporary Poland, this article argues for joining memory and populism studies in order to better understand what can happen to history in illiberal surroundings.


Sign in / Sign up

Export Citation Format

Share Document