A recent analysis has yielded information about the decline of megafauna (giant animals) in modern-day New Zealand. Evolutionary biologists compared DNA from fossils of nine species of moa, large flightless birds that lived for millions of years on the country's South Island. The birds' genetic information suggests that their populations were stable for at least 4,000 years before declining with extreme rapidity only after the arrival of humans on the New Zealand archipelago, 600 years ago.

     In reviewing possible causes for this phenomenon, the scientists dismissed the climatic explanation that accounts for the decline of other megafauna because the extinction happened long after other megafauna had disappeared at the end of the last Ice Age. They ruled out sampling bias because a sample selection impact would not have allowed for the different results observed between the nine species. They rejected the possibility of major impacts by disease or volcanic activity because consistent genetic diversity indicates that no population diminishment occurred prior to the arrival of humans to New Zealand. The lack of population decline prior to human arrival suggests that the moa extinction was caused entirely by human hunting—a hypothesis corroborated by the remains of moa at every life stage found in rubbish piles from the earliest decade of human occupation of the islands. Such evidence leads the researchers to believe that the earliest Polynesian arrivals to New Zealand engaged in indiscriminate hunting of moa and moa eggs because their large size made them attractive as easily obtained food.

     A recent underwater survey has found clues in a Mayan cenote, a type of sinkhole, about the development of the Mesoamerican city of Mayapán (1150–1450 CE). The city wall curves to avoid this particular cenote, Sac Uayum, in which research divers found more than a dozen skeletal human remains. Normally cenotes are found within city limits, to provide water, so the location of the cenote and number of remains are notably atypical.

     Researchers are considering various possibilities to explain their findings. A theory that the cenote might have served as a general city cemetery was rejected, because most city residents were interred near or under their homes. A theory of ceremonial human sacrifice was dismissed because the bones were unmarked, showing no indications of rituals or cause of death. A theory of social elitism was eliminated, because shards of other artifacts discovered at the same site were mainly those of plain water pitchers, displaying no indications of wealth or high social rank. So far the most tenable interpretation under consideration is that the cenote may have served as an attempt at contagious-disease containment—a plague pit, kept deliberately beyond the city wall and apart from drinking water supplies. The persistence into modern times of local taboos and superstitions around Sac Uayum, threatening death if the gods are not appeased with rituals before the water is approached, lends further credence to the researchers' theory.

     When Venezuelan-born political leader Simón Bolívar arrived in Europe to pursue his military education when he was a teenager, he arrived at a fortuitous time in world history. What made the time exceptional was Napoleon's 1804 coronation as emperor of France and the wars throughout Europe still ongoing in the wake of the French Revolution, which made the environment ripe for someone determined to achieve freedom, self-determination, and independence from European colonial overlords for the peoples of Latin America.

     Hoping to emulate the revolutionary successes of other colonial societies, many of the countries administered by Spain watched the radical political changes occurring in Europe and North America with longing, even as they continued to be ruled from abroad by foreign elites. The people of Latin America saw their incipient nations exploited for the profit of Madrid, just as they had been for centuries. Summarizing modern historical scholarship, most academics with knowledge of the period argue that the period of revolution in early nineteenth-century Latin America was an inevitable consequence of the dissemination of Enlightenment ideals: a mature society conscious of the prospect of self-rule will almost invariably attempt to bring about that eventuality, by armed means or otherwise.

     Some historians maintain that Bolívar is responsible for the revolutionary circumstances from which he manufactured, in the early years of the nineteenth century, the most momentous set of political changes in Latin American history. But such a narrative only obfuscates the historical trends that had already imbued most Latin American polities with a revolutionary spirit. This spirit did not originate with Bolívar; instead, he served as its focal point and primary agent in world affairs.

     In semi-aquatic ecosystems, bodies of water present peculiar difficulties for the hunting strategies of spiders. Ponds, lakes, and rivers can provide unnavigable escape vectors for prey organisms, making it likely that predators will lose out on valuable nutritional resources. The water spider Dolomedes, in particular, demonstrates adaptations that allow it to take advantage of waterborne food sources.

     The difficulty that members of the species Dolomedes face is best evidenced by the typical hunting strategies of terrestrial spiders. All spiders produce silk and arboreal species generally spin their silk into fine, latticework structures that they suspend in the environment to trap passing arthropods, which entangle themselves due to the exigencies of the forested ecosystem. In environs lacking tree coverage or comparable large structures, however, web-hunting becomes inefficient, and other strategies of predation have to be pursued. That many spider species persist in environments lacking significant tree coverage suggests that certain behavioral adaptations enable them to locate food effectively in a variety of environmental circumstances.

     One such adaptation is the proactive use of water bodies by Dolomedes, who eschew silk in favor of water tension, which they use to monitor the movements of prey animals. Organisms fall into a pond, lake, or river, and send waves vibrating from the point of impact across the surface of the pool. Dolomedes uses these vibrations to locate and capture the fallen organism. For arboreal spiders, who can only monitor the vibrations caused by insects caught in the webs they've spun, this is useless information. Such a hunting strategy does not require that the arboreal spiders pay attention to extraneous prey when other prey is acquired in abundance by other adaptations. In comparison, Dolomedes acquires its prey by yet another aquatic adaptation, using a coat of tiny, hydrophobic hairs that allow the spider to submerge itself in the liquid environment. By causing a pocket of air to gather and surround the surface of the spider's body, these hairs allow Dolomedes to submerge itself in water, thus giving it access to sources of prey closed off to other species.

     A recent trend lauds the supposedly obvious benefits of locally produced diets and of urban agriculture in particular. These benefits, they say, offer antidotes to pollution, poverty, and illness, and many advocates are urging cities to take action to encourage the growth of food farming in small urban spaces in order to introduce more locally produced food into the market.

     To evaluate these proposals, it is helpful to compare the claims with facts. A central idea of urban agriculturists is that the transportation of non-local food creates pollution. In fact, transportation constitutes a minute percentage of the agricultural sector's greenhouse gas emissions, and the production inefficiencies inherent in farming on small plots could easily erase gains made in transportation. Large rural farms transport production workers and equipment much more efficiently. Moreover, mode of transportation affects the carbon footprint of a meal. The shipment of food over long distances by train or tractor-trailer often consumes less fuel than does transportation more locally using smaller vehicles.

     For urban planners, land use is potentially the most contentious aspect of urban agriculture. Sunlit spaces, especially in the largest and most densely populated cities, often come at a premium. Given the limits on yields and profit margins for food agriculture, costs and benefits must be weighed against those of other businesses in terms of job creation, aesthetic value (since agriculture is a messy business), and scalability (local food's high price limits the market and raises the possibility of saturation). Limited space may be better utilized by housing or retail outlets than by urban gardening.

     It is obvious that there is not enough data on urban agriculture to justify implementation of agriculture-promoting policies within the limits of the largest cities. Many faddish environmental projects in the last two centuries have failed to live up to their promises and subsequently waned, and so might the urban agriculture movement. Meanwhile, the many urban farms currently in operation will have the chance to defy such cynicism, and city governments would do well to allocate resources to those that do.

     While the usual methods for taxonomy rely heavily on phenotype (physical characteristics) as markers distinguishing between species, a polyphyletic group, defined in this paper as a group including species with similar characteristics that were not inherited from a common ancestor, can defy these methods of categorization. But because other characteristics are not easily observed, the identification of polyphyletic groups takes time. Often only vigorous scientific discussion can prompt further investigation into a group's taxonomy; for instance, lively controversies about the classification of the Felimida complex of nudibranch species have resulted in genetic analyses of several specimens in an attempt to determine their origins. Such investigations may overturn decades of accepted scientific knowledge. Whereas the Felimida group had been classified based on phenotypes of four species, two of the “species” are in fact subgroups of two other species, while another, new species has been established based on the new species' lack of a common ancestor with the rest of Felimida. The usefulness of phenotype as a criterion for classification, then, appears to depend on several factors, including the phenotypic diversity of the genus as well as its interspecies interactions (for example, predator-prey interactions heavily influence phenotypic expression) and its geographic range (since similar phenotypes might evolve independently in similar but distant environments).

     Autoethnographic writing, in accounting for the subjectivities through which observers engage with culture, encourages researchers to accept the experiences of engaged participants as contributing to academic epistemology, alongside the use of “impartial” observation, in substantial and meaningful ways. These methods, unlike those of a more traditional or empirical bent, document the lived experiences of researchers as they confront cultural externalities, acknowledge the limitations of so-called objective science, and present the anxieties felt by cultural subjects as meaningful realities, mattering both to the individual and in a broader social context.

     Practitioners of autoethnography should beware, however, of thinking that their experiences are commonplace. Autoethnographic documents come no closer to the establishment of universal truth than more conventional research methods. Moreover, even when some biases are acknowledged, autoethnography is subject to a suite of prejudices and cultural influences, as well as subconscious personal tendencies, of which a researcher may not be fully cognizant. An experience had at a certain age, for example, may condition a researcher to respond to a given circumstance in a highly idiosyncratic way. Thus, an autoethnographer who writes that an adult experience played a major role in her development of ethnic or gendered consciousness might unwittingly disregard earlier experiences that were ultimately more formative.

     Among the axioms mistaken for fact by the revenue managers of most airlines is the idea that changes in fuel prices affect all competitors in a given market equally. In fact, prices—and therefore profits—fluctuate unpredictably, offering competitive advantages for some airlines and disadvantages for others. For example, a more well-established airline with an aging fleet will experience lower fuel efficiency per mile than a newer company that has invested in the latest technology, meaning fuel represents a larger percentage of the established airline's operating costs. Moreover, airlines that negotiate and lock in fuel prices with suppliers in advance enjoy stabilized expenses and efficient planning; at the same time, they may lose cost savings when market rates drop unexpectedly during the contract period. In addition, the advantages of low fuel prices are greater for those airlines whose business models focus on minimizing costs than for those with high operating budgets and higher prices for consumers. Carriers with highly efficient logistics and operations, for example, may find that falling fuel costs allow them to profitably fly routes that were previously not cost-effective, such as short routes between small cities, generating low profit margins but also increasing the size of their markets. By understanding that they have multiple options and that not all airlines experience the same effects of the volatile fuel market, airline revenue managers can offer their companies an optimized operating strategy by familiarizing themselves with the fuel market and adapting their fuel procurement plans to their business models.

     In Lemon v. Kurtzman (1971), the Supreme Court ruled that the state of Pennsylvania could not subsidize religious private schools through its Nonpublic Elementary and Secondary Education Act. Although the funds allocated in the Act were limited to the purpose of reimbursing the schools for textbooks, instructional materials, and the salaries of teachers who did not teach religion, the Court held that since the Act had the result of benefiting primarily Roman Catholic schools, it overextended the government's power on behalf of a religious organization. Later cases have referred to the benchmark three-part test established by Lemon, which states that a U.S. law violates the Establishment Clause of the Constitution if (1) the purpose of the law is not a secular purpose, (2) the law's primary effect is to inhibit or further the practice of religion, or (3) the law creates “excessive entanglement” between government and religious authority.

     Other states have also faced questions concerning whether or not a government policy or activity violates the Constitution's prohibition on the establishment of religion. For example, in Pawtucket, Rhode Island, the inclusion of a religious symbol among secular holiday decorations in a display sponsored and maintained by the city, at minimal expense, was declared constitutionally permissible. Although the religious symbol was erected on government property, it was both a longstanding tradition in the town and appeared among other, purely secular, symbols of the holiday season; it had gone unchallenged in the courts for more than 40 years. This, however, did not prevent application of the “Lemon test.” Indeed, as the Supreme Court has interpreted it, the question of establishment of religion is often a matter of perception and context as much as it is of clear divisions. This flexible approach is illustrated by Lynch v. Donnelly (1984), in which the Court demonstrated that differing circumstances could indeed lead to different results of application of the “Lemon test.” Therefore, the Court ruled that, in Pawtucket's context, the appearance of a religious symbol amid various secular ones in a government-sponsored display did not violate the Constitution.

     It is a counterintuitive but well-documented historical truth that the economies of the classical cultures typically seen as the progenitors of western liberalism and political freedom were all founded on the development and perpetuation of agrarian slavery. Because the cultures of antiquity are often associated with Periclean democracy and Roman republicanism—both oligarchical political systems at least nominally dedicated to principled and representative rule—students of history are often confused to learn that the populations of these societies contained large numbers of disenfranchised individuals who were often indentured to members of the middle and upper classes for a lifetime of brutal servitude.

     Many historians attribute this confusion to the triumphalist mythmaking of previous generations of scholars of classical history; indeed, most interpretations of classical literature and history have been distorted, but one would nonetheless expect modern revisionism and understanding of the concept of presentism to provide balance.

     Historians note that there is little discussion of slavery or its moral significance within classical sources, seemingly because individuals in the classical period saw it as both an economic necessity and inherent to the world's natural order. They cite the example of the writer Heraclitus (535 B.C.E.–475 B.C.E.), a pre-Socratic philosopher. Heraclitus is known as the “Weeping Philosopher,” and he was among the most incisive thinkers working in antiquity but, even so, the omnipresent institution of slavery struck him as an immutable element of human affairs; he wrote that “War is the father of all, the king of all … he turns some into slaves and sets others free,” implying that slavery is beyond the power of political determination—and beyond intellectual moralizing. Heraclitus is not alone in his failure to question the moral underpinnings of a slave society. Aristotle, too, suggested that the taking and keeping of slaves was a component of natural law, a fundamental consequence of military activity rather than a conscious policy that could be actively perpetuated or proscribed by the laws of man. In promoting this view, though, Aristotle demonstrates an unusual degree of circumspection, wondering whether the taking of slaves could be justified if the war in which they were acquired was itself “unjust.” The figures of early modernity saw themselves as heirs to the classical tradition and inherited the Greek and Roman attitudes toward slavery and citizenship as well as their commitments to democracy and rational inquiry, and modern historians have, in their studies of these times, endeavored to avoid the interpretive trap of imposing their modern ethics on the people of ancient times.

     Bernard Winkler's analysis of the effect of the industrialization of England on the conduct of British foreign policy through the course of the nineteenth and early twentieth centuries is a major contribution to a scholarly debate pitting two separate schools of historical thought against each other: the school of economic determinism and the school of ideological determinism.

     Winkler makes the assertion that economic and technological developments play a decisive role in military mobilization and logistical organization. Stated more simply, economic development makes extensive foreign interventions inevitable by making them simpler. Winkler implies this phenomenon has been obfuscated by a recent fondness on the part of historians for ideological explanations, of which George Nguyen's is a representative example. For Nguyen, the economic possibility of a foreign action is insignificant compared to ethnic, religious, or socio-political motivations for pursuing a course of action abroad. Economic development is construed as a mere facilitator of extant international grievances and desires such as border disputes, enmity between competing religious sects, and long-term foreign policy goals. This contention represents a significant trend in academic historiography, and it is known as ideological determinism.

     Ideological determinists entrench themselves by embracing a mistaken interpretation of economic determinism: for example, economic determinists are supposed to contend that economic development is responsible for all the various subtleties of foreign policy implementation. The alternative to ideological determinism, to say it another way, is to see economics as coextensive with society, as being responsible for even the most minor variations in social phenomena.

     Winkler undermines the misrepresentations of the ideological determinists by means both conceptual and concrete. Conceptually, he defines “economic causes” according to the interactions of industrialization with extant political and sociological realities. Descriptions of sociological and political phenomena as wholly divorced from economic factors are untenable because a state can hardly feed its armies on ideas alone. On a more concrete level, Winkler shows that rapid advances in economic production opened new vistas for political interpretation, religious expression, international relations, and the organization of armies. Some developments Winkler attributes to the ways politicians and bodies politic reacted to the new realities of industrialization, whereas others are attributed to industrialization itself. Therefore, Winkler responds to the question: “When are economic causes decisive and when are the interpretations of changing economic realities more significant?”

     Koltsov predicted in 1927 that an organism's inherited traits are determined by gradual changes in a “giant hereditary molecule,” later known as DNA, that is the building block of the genome that determines an organism's genetic makeup. This hypothesis was unproven, for a time, because of limitations in experimental methodology and an inability to do much more than observe qualities of an organism's DNA compared to the traits it expressed.

     To determine the nature of the connection between DNA and heritable characteristics, scientists needed to be able to bring about changes in the genome and observe whether they corresponded to physical changes in the organism. An experiment conducted by Zimmer in 1935 indicated that this was possible: radiation applied to living tissue can change the structures of DNA and another nucleic acid, RNA, that are found in the cells of every organism. Most of the exposed molecules go unchanged in this experiment, but some of them respond to experimental pressures. When X-rays are applied to cells, the nucleic acids warp and rearrange themselves, sometimes dramatically altering the traits they cause the organism to express. Because the changes induced by radiation exposure are more rapid and intense than those brought about by natural selection, significantly altered heritable traits can be observed in a single generation.

    As a proof of the connection between DNA and heritable characteristics, radiation experiments have two advantages. First, they are universally applicable: the genome of any organism responds to radiation exposure in a way comparable to any other organism. Second, it is a more direct means of genetic intervention than other methods like selective breeding. These advantages mean that radiation experiments can be used to isolate the hereditary influence of DNA from other confounding variables. The results of these experiments demonstrate that DNA exerts a substantial influence on the hereditary characteristics organisms express: DNA is the way that organisms transfer heritable traits between generations. These experiments have established an unassailable connection between intergenerational biological change and the information contained within the building blocks of the genome.

    However, it is important to note that there are other biological mechanisms, such as epigenetics and certain environmental pressures, that also affect the expression of inherited characteristics. The advantage of the Koltsov theory is its broad applicability; DNA is present in every organism on earth, which is not true of the various other factors that might have a role to play in determining the expression of heritable characteristics. That said, the comparative immeasurability of these other potential influences does not make them unworthy of study.

     The general theory of relativity posits that major events in the universe, such as the creation of a black hole, create ripples in the space-time continuum, also known as gravitational waves, which were recently detected for the first time by the Laser Interferometer Gravitational Observatory (LIGO). Though the interferometer was invented in 1887, not until 2002 was one used in an attempt to detect gravitational waves. The instrument splits a laser beam so that the two resulting beams travel down perpendicular arms—perfectly identical tubes that are four kilometers long—then hit mirrors and return to their shared origin point. This allows the instrument to detect extremely minute changes in the lengths of the arms. In the absence of a gravitational wave, the wavelengths of the two beams match up perfectly. However, if something interferes with the beams' paths, their peaks and valleys no longer align, and the instrument registers the interference.

     Gravitational waves cause space to shrink in one direction and expand in a perpendicular direction. If the interferometer is hit by a gravitational wave, one arm will grow and the other will shrink by normally imperceptible amounts, but the differing distances traveled by the laser beams are registered by the instrument. The LIGO actually consists of two interferometers, thousands of kilometers apart, which compare data in order to rule out localized vibrations and flickers. In September 2015 it detected its first gravitational wave, which was determined to have been generated by the collision of two black holes between one and two billion years ago. Another gravitational wave was detected in December 2015.

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