scholarly journals A multiscale stratigraphic investigation of the context of StW 573 ‘Little Foot’ and Member 2, Sterkfontein Caves, South Africa

2018 ◽  
Author(s):  
Laurent Bruxelles ◽  
Dominic J. Stratford ◽  
Richard Maire ◽  
Travis R. Pickering ◽  
Jason L. Heaton ◽  
...  
Keyword(s):  
Multiple Scales ◽  
Alternative Hypothesis ◽  
Cave System ◽  
Hominin Evolution ◽  
Geological Age ◽  
History Of ◽  
Depositional Units ◽  
Foot Skeleton ◽  
Fossil Hominin ◽  
Mixed Age

AbstractThe Sterkfontein Caves has an 80 year history of yielding remarkable evidence of hominin evolution and is currently the world’s richest Australopithecus-beafing site. Included in Sterkfontein’s hominin assemblage is StW 573 (‘Little Foot’). Discovered in the Member 2 deposit in the Silberberg Grotto, StW 573 represents the most complete Australopithecus skeleton yet found. Because of its importance to the fossil hominin record, the geological age of Little Foot has been the subject of significant debate. Two main hypotheses have been proposed regarding the formation and age of Member 2 and by association StW 573. The first, proposes that Member 2 formed relatively rapidly, starting to accumulate at around 2.8 million years ago and that the unit is isolated to the Silberberg Grotto - the underlying chambers and passages forming later. The second proposes that Member 2 formed slowly, its accumulation starting before 3.67 million years ago and that the deposit extends into the Milner Hall and close to the base of the cave system. Both assume a primary association between StW 573 and Member 2, although which sediments in the Silberberg Grotto are associated with Member 2 has also been questioned. Recently a third alternative hypothesis questioning the association of StW 573 to Member 2 sediments proposed a ‘two-stage burial scenario’ in which sediments associated with StW 573 represent a secondary and mixed-age deposit reworked from a higher cave. The stratigraphic and sedimentological implications of these hypotheses are tested here through the application of a multiscale investigation of Member 2, with reference to the taphonomy of the Little Foot skeleton. The complete infilling sequence of Member 2 is described and depositional units are tracked across all exposures of the deposit in the Silberberg Grotto and into the Milner Hall. Facies development follows patterns characteristic of colluvially accumulated taluses with 30-40° angles of repose developing coarser distal facies. Sediments are generally stratified and conformably deposited in a sequence of silty sands eroded from well-developed lateritic soils on the landscape surface. Voids, clasts and bioclasts are organized consistently across and through Member 2 according to the underlying deposit geometry, indicating a gradual deposit accretion with no distinct collapse facies evident, no successive debris flow accumulation, and only localized intra-unit post- depositional modification. The stratigraphy and sedimentology of Member 2 supports a simple single-stage accumulation process through which Member 2 partially fills the Silberberg Grotto and extends into the deeper chambers and passages of the Sterkfontein Caves. Through this work we demonstrate at multiple scales the primary association between the sediments of Member 2 and the StW 573 ‘Little Foot’ skeleton.

scholarly journals Cosmogenic burial dating of in cave-deposited alluvium: unravelling long-term incision rates and complex speleogenesis in multi-level cave systems

2020 ◽  
Author(s):  
Gilles Rixhon ◽  
Didier L. Bourlès ◽  
Régis Braucher ◽  
Alexandre Peeters ◽  
Alain Demoulin
Keyword(s):  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Fluvial Terrace ◽  
Base Level ◽  
Cave System ◽  
River Incision ◽  
Order Of Magnitude ◽  
History Of ◽  
Multi Level

<p>Multi-level cave systems record the history of regional river incision in abandoned alluvium-filled phreatic passages which, mimicking fluvial terrace sequences, represent former phases of fluvial base-level stability. In this respect, cosmogenic burial dating of in cave-deposited alluvium (usually via the nuclide pair <sup>26</sup>Al/<sup>10</sup>Be) represents a suitable method to quantify the pace of long-term river incision. Here, we present a dataset of fifteen <sup>26</sup>Al/<sup>10</sup>Be burial ages measured in fluvial pebbles washed into a multi-level cave system developed in Devonian limestone of the uplifted Ardenne massif (eastern Belgium). The large and well-documented Chawresse system is located along the lower Ourthe valley (i.e. the main Ardennian tributary of the Meuse river) and spans altogether an elevation difference exceeding 120 m.</p><p>The depleted <sup>26</sup>Al/<sup>10</sup>Be ratios measured in four individual caves show two main outcomes. Firstly, computed burial ages ranging from ~0.2 to 3.3 Ma allows highlighting an acceleration by almost one order of magnitude of the incision rates during the first half of the Middle Pleistocene (from ~25 to ~160 m/Ma). Secondly, according to the relative elevation above the present-day floodplain of the sampled material in the Manants cave (<35 m), the four internally-consistent Early Pleistocene burial ages highlight an “anomalous” old speleogenesis in the framework of a gradual base-level lowering. They instead point to intra-karsting reworking of the sampled material in the topographically complex Manants cave. This in turn suggests an independent, long-lasting speleogenetic evolution of this specific cave, which differs from the <em>per descensum</em> model of speleogenesis generally acknowledged for the regional multi-level cave systems and their abandoned phreatic galleries. In addition to its classical use for inferring long-term incision rates, cosmogenic burial dating can thus contribute to better understand specific and complex speleogenetic evolution.</p>

scholarly journals EFICACIA DE LOS MAPAS CONCEPTUALES COMO RECURSO DIDÁCTICO EN EL APRENDIZAJE DE LAS CIENCIAS SOCIALES EN LA ESCUELA ACADÉMICO PROFESIONAL DE TURISMO, HOTELERÍA Y GASTRONOMÍA DE LA UNIVERSIDAD ALAS PERUANAS

LOGOS ◽  
2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Mg. Rafael Antonio Garay Argandoña
Keyword(s):  
Social Sciences ◽  
Learning Process ◽  
Concept Maps ◽  
Alternative Hypothesis ◽  
Sampling Technique ◽  
Teaching Resource ◽  
History Of ◽  
History Of Culture ◽  
Academic School ◽  
Mind Maps

EFICACIA  DE  LOS    MAPAS CONCEPTUALES COMO RECURSO DIDÁCTICO EN EL APRENDIZAJE DE LAS CIENCIAS SOCIALES EN LA ESCUELA ACADÉMICO PROFESIONAL DE TURISMO, HOTELERÍA Y GASTRONOMÍA DE LA UNIVERSIDAD ALAS PERUANAS EFFECTIVENESS OF MIND MAPS AS TEACHING RESOURCE IN THE LEARNING PROCESS OF SOCIAL SCIENCES IN THE PROFESSIONAL ACADEMIC SCHOOL OF TOURISM, HOSPITALITY AND CUISINE OF PERUVIAN UNIVERSITY ALAS PERUANAS RESUMEN Objetivo. El objetivo de la Investigación fue Determinar que el desconocimiento del manejo de los mapas conceptuales como recurso didáctico influye en el aprendizaje de las Ciencias Sociales en los estudiantes del II ciclo de la Escuela Académico Profesional de Turismo Hotelería y Gastronomía UAP Materiales y Métodos. Para la selección de la muestra se consideró a los estudiantes del II ciclo de la escuela, la técnica de muestreo fue sistemático, se trabajó desarrollando clases haciendo uso de mapas conceptuales en la asignatura de historia de la cultura se aplicó la prueba estadística de hi2 teniendo en cuenta la relación de variables Resultados. Como el valor calculado es mayor al de la tabla (24.894 > 16.919), la hipótesis nula es rechazada, aceptándose la hipótesis alterna H1, con lo cual queda demostrada la hipótesis. Conclusión. El manejo de los mapas conceptuales como recurso didáctico influye significativamente en el aprendizaje de los alumnos, produce un auténtico aprendizaje, porque proporciona conceptos de manera coherente y no arbitraria, “construyendo”, de manera sólida los conceptosABSTRACT Objective. The aim of the research was to determine that the lack of management of mind maps as a teaching resource influences in the learning of Social Sciences students in cycle II of the Professional Academic School of Tourism Hospitality and Gastronomy in Alas Peruanas University.  For the selection of the sample, the students of the second cycle school were considered, the sampling technique was systematic, classes were developed making use of concept maps in the history of culture subject statistic hi2 tests were applied taking in account the variables relation. ResultsAs the calculated value is bigger that the table (24,894> 16,919), the null hypothesis is rejected accepting the alternative hypothesis H1whereupon, the hypothesis ends up being demonstrated. In conclusion. The management of mind maps as a teaching resource influences significantly on the student learning process, It produces an effective learning because it provides concepts in a coherent and not arbitrary way by “building” concepts solidly.

scholarly journals Managing Balance: Pursuit of Equilibrium Permeates the History of Science and Influences Contemporary Investigations

2019 ◽  
Author(s):  
J. Kasmire
Keyword(s):  
Sustainability Science ◽  
Multiple Scales ◽  
Scientific Research ◽  
Subsequent Development ◽  
Scientific Development ◽  
Human Society ◽  
Carbon Neutrality ◽  
History Of ◽  
The Individual ◽  
Successes And Failures

AbstractThe word “sustainable” débuted in 1987 but has since become a hot topic issue, both for scientific research and wider society. Although sustainability may appear to be a thoroughly twenty-first century goal, sustainability science concepts and goals such as balance, endurance, order and change, reach back at least as far as the proto-scientific investigations of alchemy. Both alchemy and sustainability science can be understood as systems or strategies which individuals and societies can use to organise and manage themselves in a complex world filled with dynamic problems. Alchemy never created a panacea or transmuted base metals into gold because those goals proved to be based on fundamentally flawed theories and premises. Nevertheless, alchemy did succeed in helping adherents manage themselves and their societies in advantageous ways. Alchemy also positively and significantly influenced subsequent scientific development. Likewise, science helps humanity manage itself on multiple scales, from the individual to the international, and will certainly contribute to further scientific research and development. However, it is not yet known whether carbon neutrality, entirely renewable energy and other sustainability goals will be achieved or whether these goals will also come to be seen as based on flawed understandings and theories. For this reason, this article explores key features of alchemy, traces how they persisted through Enlightenment-era science and how they continue to be present and influential within scientific efforts today. The article goes on to reflect on how the history, development and continued use of concepts such as balance, endurance, order and change may be useful portents of how humans and human society will manage themselves in the future. Such reflections may also temper the zeal with which individuals that accept or reject sustainability goals treat each other, thereby offering a way for divergent groups to manage their interactions. Flawed theories prevented alchemy from achieving many of its primary stated goals. However, alchemy was very beneficial, both during its period of use and subsequently through its influence on subsequent development. This article identifies ideas from alchemy that were originally beneficial and that have persisted through Enlightenment-era science and into contemporary science. The article also explores how those ideas continue to influence scientific and sustainability goals today. Understanding and reflecting on alchemy’s successes and failures facilitates reflection on the potential successes and failures of sustainability and the human consequences of trying to manage a sustainable future.

Exoplanets: Atmospheres of Hot Jupiters

2019 ◽  
Author(s):  
Dmitry V. Bisikalo ◽  
Pavel V. Kaygorodov ◽  
Valery I. Shematovich
Keyword(s):  
Solar System ◽  
Alternative Hypothesis ◽  
Atmospheric Composition ◽  
Current Status ◽  
Hot Jupiters ◽  
History Of ◽  
Exoplanetary Atmospheres ◽  
Host Stars ◽  
Gaseous Envelopes ◽  
Hot Jupiter

The history of exoplanetary atmospheres studies is strongly based on the observations and investigations of the gaseous envelopes of hot Jupiters—exoplanet gas giants that have masses comparable to the mass of Jupiter and orbital semi-major axes shorter than 0.1 AU. The first exoplanet around a solar-type star was a hot Jupiter discovered in 1995. Researchers found an object that had completely atypical parameters compared to planets known in the solar system. According to their estimates, the object might have a mass about a half of the Jovian mass and a very short orbital period (four days), which means that it has an orbit roughly corresponding to the orbit of Mercury. Later, many similar objects were discovered near different stars, and they acquired a common name—hot Jupiters. It is still unclear what the mechanism is for their origin, because generally accepted theories of planetary evolution predict the formation of giant planets only at large orbital distances, where they can accrete enough matter before the protoplanetary disc disappears. If this is true, before arriving at such low orbits, hot Jupiters might have a long migration path, caused by interactions with other massive planets and/or with the gaseous disc. In favor of this model is the discovery of many hot Jupiters in elliptical and highly inclined orbits, but on the other hand several observed hot Jupiters have circular orbits with low inclination. An alternative hypothesis is that the cores of future hot Jupiters are super-Earths that may later intercept matter from the protoplanetary disk falling on the star. The scientific interest in hot Jupiters has two aspects. The first is the peculiarity of these objects: they have no analogues in the solar system. The second is that, until recently, only for hot Jupiters was it possible to obtain observational characteristics of their atmospheres. Many of the known hot Jupiters are eclipsing their host stars, so, from their light curve and spectral data obtained during an eclipse, it became possible to obtain information about their shape and their atmospheric composition. Thus it is possible to conclude that hot Jupiters are a common type of exoplanet, having no analogues in the solar system. Many aspects of their evolution and internal structure remain unclear. Being very close to their host stars, hot Jupiters must interact with the stellar wind and stellar magnetic field, as well as with stellar flares and coronal mass ejections, allowing researchers to gather information about them. According to UV observations, at least a fraction of hot Jupiters have extended gaseous envelopes, extending far beyond of their upper atmospheres. The envelopes are observable with current astronomical instruments, so it is possible to develop their astrophysical models. The history of hot Jupiter atmosphere studies during the past 20 years and the current status of modern theories describing the extended envelopes of hot Jupiters are excellent examples of the progress in understanding planetary atmospheres formation and evolution both in the solar system and in the extrasolar planetary systems.

Experiments on egg discrimination in two North American corvids: further evidence for retention of egg ejection

2004 ◽  
Vol 82 (9) ◽  
pp. 1399-1407 ◽  
Author(s):  
Todd J Underwood ◽  
Spencer G Sealy ◽  
Celia M McLaren
Keyword(s):  
Brood Parasitism ◽  
Alternative Hypothesis ◽  
Egg Discrimination ◽  
Corvus Brachyrhynchos ◽  
Detection Model ◽  
Egg Ejection ◽  
Significant Difference ◽  
History Of ◽  
Pica Nuttalli ◽  
High Level

In the absence of brood parasitism in North America, black-billed magpies, Pica hudsonia (Sabine, 1822), and yellow-billed magpies, Pica nuttalli (Audubon, 1837), may have retained egg-discrimination behaviour that evolved in Eurasian magpies, Pica pica (L., 1758), in response to parasitism by Old World cuckoos. We further examined this hypothesis by testing the egg-discrimination abilities of black-billed magpies and the American crow, Corvus brachyrhynchos Brehm, 1822, which has no history of brood parasitism. In addition, we tested an alternative hypothesis that black-billed magpies evolved or retained egg discrimination to counter conspecific parasitism by testing their ability to eject foreign conspecific eggs and by using a signal detection model to estimate the level of conspecific parasitism required for ejection to be favoured. Black-billed magpies ejected all non-mimetic eggs and 62% of mimetic eggs. Significantly more mimetic eggs were ejected during the incubation stage than during the laying stage. Magpies ejected significantly more non-mimetic eggs than mimetic eggs overall, but there was no difference in ejection frequency during incubation. American crows ejected 21% of non-mimetic eggs and 8% of mimetic eggs. There was no significant difference in ejection frequency of the two egg types. Black-billed magpies ejected 11% of conspecific eggs and a relatively high level of conspecific parasitism (22%–49%) would be required to select for conspecific ejection, which provides little support for conspecific parasitism as a current selection pressure for maintaining egg discrimination. Thus, black-billed magpies appear to have retained egg rejection in the absence of parasitism through speciation from Eurasian magpies.

scholarly journals I. Contributions to the history of the pleiocene and pleistocene deer. Part I. Cervus verticornis, Cervus savini

1885 ◽  
Vol 38 (235-238) ◽  
pp. 345-345 ◽  
Keyword(s):  
Old Age ◽  
Large Series ◽  
The Other ◽  
Early Pleistocene ◽  
Geological Age ◽  
History Of ◽  
The One

The numerous cervine remains which occur in the various collections in Britain and on the Continent have been studied by the author for the last twenty-five years, and in this communication two species, the one hitherto ill-defined, and the other new to science, have been described. The first, or Cervus verticornis , Dawkins, remarkable for the singular forward and downward curvature of the first tine, is represented by a large series of skulls and antlers, which enable the author to define the changes in antler-form from youth to old age, as well as to relegate it to the division of deer with palmated antlers, and to establish its geological age to be Pleiocene, and early Pleistocene, in Norfolk and Suffolk.

The History of ‘Nervous Disorders' from 1600 to 1840, and a Comparison with Modern Views

1991 ◽  
Vol 159 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Edward Hare
Keyword(s):  
18Th Century ◽  
Pathological Change ◽  
Alternative Hypothesis ◽  
General Term ◽  
Physical Disorder ◽  
Du Bois ◽  
Nervous Disorder ◽  
History Of ◽  
Modern Era ◽  
Nervous Conduction

In the 18th century the main varieties of nervous illness – hypochondria, hysteria, the spleen, the vapours and dyspepsia – became included under the general term ‘nervous disorders'. When no physical disorder of the nerves could be detected in such conditions, the hypothesis of nervous disorder was replaced by the more vague concept of ‘nervous temperament’. The fact that there is still no evidence of pathological change in such cases continues to expose physicians to the alternative hypothesis of a purely psychological cause. The modern era in our understanding of the nervous system may be said to date from 1843 when Du Bois Reymond showed the electrical nature of nervous conduction. The publication of Jordan'sBriefe Discoursein 1603 may be taken to represent the start of a discrete period (1600 to 1840) in the history of neurotic illness.

SEDIMENTOLOGY AND DEPOSITIONAL HISTORY OF THE RISING STAR CAVE SYSTEM: PROVIDING A FRAMEWORK FOR TAPHONOMIC AND GEOCHRONOLOGIC INVESTIGATIONS

2016 ◽  
Author(s):  
Hannah L. Hilbert-Wolf ◽  
◽  
Eric M. Roberts ◽  
Paul H.G.M. Dirks ◽  
Jess L. Robbins ◽  
...  
Keyword(s):  
Depositional History ◽  
Cave System ◽  
History Of

scholarly journals Hardin’s imagined tragedy is pig shit: A call for planning to recenter the commons

2019 ◽  
Vol 19 (1) ◽  
pp. 127-144 ◽  
Author(s):  
Catherine Brinkley
Keyword(s):  
Phase Shift ◽  
Multiple Scales ◽  
Planning Practice ◽  
Functional Theory ◽  
Formal Economy ◽  
Self Sufficiency ◽  
History Of ◽  
The Commons ◽  
User Groups ◽  
Global Population

Hardin was wrong. There was not a tragedy of overuse. The Commons were dismantled by the state to make room for the formal economy and higher income user groups. I revisit the history of the Commons as a central, planned space in cities in order to ask two main questions. First, what role did the Commons play for cities and how is its lost felt? Second, how might planning reintroduce the Commons? In response, this research builds a functional theory of self-sufficiency at multiple scales of governance based on the opportunities of the Commons. The conclusion charts an urgent agenda for planning practice during a global population phase shift as cities increasingly house a greater proportion of humanity.

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