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The Toba supereruption 74,000 years ago was so massive it may have plunged Earth into years of darkness and cold, leading some scientists to believe humanity nearly went extinct。 Yet archaeological evidence from Africa and Asia suggests early humans were far more resilient than once thought。 Instead of disappearing, some communities adapted with ne
As more sex workers quit the industry, some are having to navigate tough questions around consent and the “afterlife” of work they no longer want to be associated with
Biohacker Bryan Johnson recently bragged about his girlfriend's “top 1%” vagina as the at-home vaginal microbiome test industry is thriving。 But experts are skeptical
Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects.
First, the span of absolute judgment and the span of immediate memory impose severe limitations on the amount of information that we are able to receive, process, and remember. By organizing the stimulus input simultaneously into several dimensions and successively into a sequence or chunks, we manage to break (or at least stretch) this informational bottleneck. Second, the process of recoding is a very important one in human psychology and deserves much more explicit attention than it has received. In particular, the kind of linguistic recoding that people do seems to me to be the very lifeblood of the thought processes. Recoding procedures are a constant concern to clinicians, social psychologists, linguists, and anthropologists and yet, probably because recoding is less accessible to experimental manipulation than nonsense syllables or T mazes, the traditional experimental psychologist has contributed little or nothing to their analysis. Nevertheless, experimental techniques can be used, methods of recoding can be specified, behavioral indicants can be found. And I anticipate that we will find a very orderly set of relations describing what now seems an uncharted wilderness of individual differences. Third, the concepts and measures provided by the theory of information provide a quantitative way of getting at some of these questions. The theory provides us with a yardstick for calibrating our stimulus materials and for measuring the performance of our subjects. In the interests of communication I have suppressed the technical details of information measurement and have tried to express the ideas in more familiar terms; I hope this paraphrase will not lead you to think they are not useful in research. Informational concepts have already proved valuable in the study of discrimination and of language; they promise a great deal in the study of learning and memory; and it has even been proposed that they can be useful in the study of concept formation. A lot of questions that seemed fruitless twenty or thirty years ago may now be worth another look. In fact, I feel that my story here must stop just as it begins to get really interesting. And finally, what about the magical number seven? What about the seven wonders of the world, the seven seas, the seven deadly sins, the seven daughters of Atlas in the Pleiades, the seven ages of man, the seven levels of hell, the seven primary colors, the seven notes of the musical scale, and the seven days of the week? What about the seven-point rating scale, the seven categories for absolute judgment, the seven objects in the span of attention, and the seven digits in the span of immediate memory? For the present I propose to withhold judgment. Perhaps there is something deep and profound behind all these sevens, something just calling out for us to discover it. But I suspect that it is only a pernicious, Pythagorean coincidence.
The usefulness of the electrical resistivity log in determining reservoircharacteristics is governed largely by:the accuracy with which the trueresistivity of the formation can be determined;the scope of detailed dataconcerning the relation of resistivity measurements to formationcharacteristics;the available information concerning the conductivity ofconnate or formation waters;the extent of geologic knowledge regardingprobable changes in facies within given horizons, both vertically andlaterally, particularly in relation to the resultant effect on the electricalproperties of the reservoir. Simple examples are given in the following pagesto illustrate the use of resistivity logs in the solution of some problemsdealing with oil and gas reservoirs. From the available information, it isapparent that much care must be exercised in applying to more complicated casesthe methods suggested. It should be remembered that the equations given are notprecise and represent only approximate relationships. It is believed, however, that under favorable conditions their application falls within useful limits ofaccuracy. Introduction The electrical log has been used extensively in a qualitative way tocorrelate formations penetrated by the drill in the exploitation of oil and gasreservoirs and to provide some indication of reservoir content. However, itsuse in a quantitative way has been limited because of various factors that tendto obscure the significance of the electrical readings obtained. Some of thesefactors are the borehole size, the resistivity of the mud in the borehole, theeffect of invasion of the mud filtrate into the formation, the relation of therecorded thickness of beds to electrode spacing, the heterogeneity of geologicformations, the salinity or conductivity of connate water, and, perhaps ofgreatest importance, the lack of data indicating the relationship of theresistivity of a formation in situ to its character and fluid content. On the Gulf Coast it is found that the effects of the size of the boreholeand the mud resistivity are generally of little importance, except when dealingwith high formational resistivities or extremely low mud resistivities.Fortunately, little practical significance need be attached to the exact valuesof the higher resistivities recorded. Low mud resistivities are not common, butwhen this condition is encountered it may be corrected by replacing the mudcolumn. With the present advanced knowledge of mud control, invasion of mudfiltrate into sands can be minimized, thereby increasing the dependability ofthe electrical log. The effect of electrode spacing on the recorded thicknessof a bed is often subject to compensation or can be sufficiently accounted forto provide an acceptable approximation of the true resistivity of theformation. T.P. 1422
This study is about the principles for constructing polite speech. The core of it was published as Brown and Levinson (1978); here it is reissued with a new introduction which surveys the now considerable literature in linguistics, psychology and the social sciences that the original extended essay stimulated, and suggests new directions for research. We describe and account for some remarkable parallelisms in the linguistic construction of utterances with which people express themselves in different languges and cultures. A motive for these parallels is isolated - politeness, broadly defined to include both polite friendliness and polite formality - and a universal model is constructed outlining the abstract principles underlying polite usages. This is based on the detailed study of three unrelated languages and cultures: the Tamil of south India, the Tzeltal spoken by Mayan Indians in Chiapas, Mexico, and the English of the USA and England, supplemented by examples from other cultures. Of general interest is the point that underneath the apparent diversity of polite behaviour in different societies lie some general pan-human principles of social interaction, and the model of politeness provides a tool for analysing the quality of social relations in any society.
The conditions associated with the existence and stability of democratic society have been a leading concern of political philosophy. In this paper the problem is attacked from a sociological and behavioral standpoint, by presenting a number of hypotheses concerning some social requisites for democracy, and by discussing some of the data available to test these hypotheses. In its concern with conditions—values, social institutions, historical events—external to the political system itself which sustain different general types of political systems, the paper moves outside the generally recognized province of political sociology. This growing field has dealt largely with the internal analysis of organizations with political goals, or with the determinants of action within various political institutions, such as parties, government agencies, or the electoral process. It has in the main left to the political philosopher the larger concern with the relations of the total political system to society as a whole.
A new kind of memory device may finally solve the problem of overheating and battery drain in electronics。 By shrinking components to an extreme scale and redesigning their structure, researchers found a way to reduce energy loss instead of increasing it。 The result is a tiny memory unit that improves as it gets smaller—something once thought impos
Astronomers have spotted something surprising in the far outer Solar System—a faint, short-lived atmosphere clinging to a tiny icy world that shouldn’t be able to hold one at all。 The object, called 2002 XV93, is far smaller than Pluto, yet observations during a rare stellar alignment revealed its presence through a subtle dimming of starlight。 Eve
Curiosity has detected a surprising variety of organic molecules on Mars, including compounds tied to the chemistry of life。 Some of these molecules may be billions of years old, preserved in ancient clay-rich rocks that once held water。 One standout find resembles building blocks of DNA, raising exciting questions about Mars’ past
Fur seals may look like they’re simply resting after exhausting hunting trips at sea, but their bodies are secretly working overtime。 Scientists discovered that hours after returning to land, the seals’ heart rates suddenly surge — sometimes doubling — as they recover from the intense physical stress of deep diving。 The findings suggest that seals
A group of undergraduate students pulled off something remarkable: they built their own dark matter detector and used it to probe one of physics’ biggest mysteries。 Working with limited resources but plenty of creativity, they designed a stripped-down experiment to hunt for axions — hypothetical particles that could make up dark matter
Scientists revisiting mysterious 540-million-year-old microfossils from Brazil have overturned a major idea about early animal life。 What were once thought to be trails left behind by tiny worm-like creatures are now believed to be fossilized communities of bacteria and algae — some with remarkably preserved cells and organic material still intact
As blood stem cells age, their lysosomes become overactive and damaged, triggering inflammation and weakening the body’s ability to regenerate healthy blood and immune cells。 By calming this cellular “overdrive,” researchers restored the stem cells’ youthful function, dramatically boosting their ability to regenerate and produce balanced blood cell
Astronomers using the James Webb Space Telescope have spotted something that shouldn’t exist—at least not so early in the universe。 A massive galaxy, formed less than 2 billion years after the Big Bang, appears to have no rotation at all, a trait usually seen only in much older, evolved galaxies。 This challenges current theories that young galaxies
Tyrannosaurs may be famous as fearsome apex predators, but new research reveals a more opportunistic—and slightly grim—side to their behavior。 Using high-resolution 3D scans, a researcher identified precise bite marks on a massive tyrannosaur foot bone, showing that a smaller tyrannosaur had fed on the remains of a much larger relative over 75 mill
Centuries ago in England, hats weren’t just accessories—they were statements of power and rebellion。 Refusing to remove a hat could challenge authority, even in courtrooms and before kings。 People valued their hats so deeply that robbery victims sometimes begged to keep them over money