IELTS Academic Reading Practice Test 41

A For nearly half a century after it was first proposed, the Higgs boson remained one of the most elusive predictions in modern physics. The particle was originally hypothesised in 1964 by a small group of theorists working independently, among whom the British physicist Peter Higgs has received the broadest public recognition. Their proposal was designed to solve a deep puzzle in the so-called Standard Model of particle physics: why some elementary particles appear to possess mass while others, such as the photon, do not. Their solution invoked an invisible field permeating all of space, whose interactions with other particles would give them their measured masses. The particle eventually known as the Higgs boson is considered to be the visible quantum of that field.

B The theoretical framework was accepted by most particle physicists by the late 1970s, but direct experimental evidence remained out of reach for several decades. The principal difficulty was that the Higgs particle was widely predicted to be both extremely massive by elementary-particle standards and extraordinarily short-lived, decaying in roughly a sextillionth of a second into more familiar particles whose tracks could be more easily observed. To produce a Higgs particle in any quantity, physicists argued, it would be necessary to collide other particles at energies far higher than those available to most laboratories of the period.

C A major step toward closing that gap was taken with the construction of the Large Hadron Collider, a circular tunnel about 27 kilometres in circumference straddling the Franco-Swiss border near Geneva. The collider, operated by the European Organisation for Nuclear Research and known by its French acronym CERN, was designed to accelerate protons to within a tiny fraction of the speed of light and then to collide them head-on inside enormous detectors. By 2010 the machine was producing collisions at an energy of seven trillion electronvolts, considered sufficient to generate Higgs particles in detectable numbers if the theoretical predictions about its mass were even approximately correct.

D Two of the largest detector experiments at the Large Hadron Collider, known as ATLAS and CMS, took on the task of searching for evidence of the Higgs particle. Each instrument involves several thousand physicists from dozens of countries and is built around layered systems for tracking the trajectories, energies, and identities of particles produced in collisions. Because the Higgs boson decays so rapidly, neither detector can observe one directly; instead, researchers must identify characteristic patterns of decay products, such as pairs of photons or particular combinations of leptons, and infer the brief existence of a parent particle through statistical analysis of millions of similar events.

E On 4 July 2012, the directors of ATLAS and CMS announced jointly at a seminar in Geneva that both experiments had observed signals statistically consistent with a new particle whose mass was approximately 125 billion electronvolts, in the range predicted for the Higgs boson. The announcement was timed to precede the start of a major physics conference and was watched live by scientists worldwide. Peter Higgs himself attended the seminar and was seen wiping away tears as the results were displayed; the elder theorist Francois Englert, who had published a closely related proposal in 1964, sat beside him. The combined evidence was considered sufficient to constitute a discovery rather than merely a hint, although confirmation that the new particle behaved precisely as a Standard Model Higgs would require further data.

F Subsequent analyses confirmed that the 125 billion electronvolt particle decays into other particles in ratios consistent with the Standard Model prediction. Higgs and Englert were jointly awarded the Nobel Prize in Physics in 2013, an honour that critics have argued ought to have been shared more widely with the other 1964 theorists, several of whom had died before the experimental confirmation. Some particle physicists have proposed that the Higgs boson observed at the Large Hadron Collider may not be the only particle of its kind: certain extensions of the Standard Model, such as supersymmetry, generally predict additional Higgs-like states at higher masses. Whatever those searches eventually yield, the 2012 discovery is widely considered to have completed the experimental verification of the original Standard Model.

A The European coffee house, in the form generally familiar today, can be traced to the second half of the seventeenth century, although its origins reach considerably further back. Coffee itself had been cultivated in the Yemeni highlands since at least the fifteenth century and was being consumed as a fashionable drink in Cairo, Damascus, and Istanbul by 1550. The first coffee houses in the Ottoman Empire were modest establishments where men, and almost never women, gathered to drink, smoke, exchange news, and play board games. Western travellers passing through Istanbul described these establishments with a mixture of fascination and unease.

B The earliest European coffee houses generally appear to have opened in the 1640s and 1650s. Venice, with its extensive trading networks in the eastern Mediterranean, hosted one of the first, although precise dating is contested. Oxford acquired its first coffee house in 1651, when a Jewish entrepreneur named Jacob is recorded as having opened an establishment at the sign of the Angel. London followed soon afterwards: by the end of the 1650s, several coffee houses were operating in the city, often run by immigrants from southern Europe or the Levant. Within two decades, similar establishments were to be found in Paris, Marseille, Hamburg, Amsterdam, and a number of central European cities.

C The cultural function of the European coffee house differed in important ways from that of the tavern, which it partially supplanted. Whereas taverns served alcohol and were widely associated with rowdiness and intoxication, coffee houses offered a non-alcoholic alternative and were considered conducive to clear-headed conversation. Newspapers, pamphlets, and printed sermons were laid out on long communal tables, and patrons read, discussed, and disputed the news of the day. Many establishments quickly became known for particular clienteles or specialisms: certain London houses, for example, attracted merchants concerned with shipping insurance, while others gathered scientists, members of literary circles, or political dissenters.

D The political importance of these venues was not lost on contemporary governments. King Charles II of England attempted in 1675 to suppress coffee houses entirely by royal proclamation, on the grounds that they were "Places where the disaffected met, and spread scandalous Reports concerning the Conduct of His Majesty and his Ministers." Public protest was intense, and the proclamation was effectively withdrawn within days. In France, Cardinal Mazarin and his successors treated coffee houses with greater tolerance, although surveillance by police informers became routine in eighteenth-century Paris. Across much of Europe, attempts to control or close coffee houses tended to be short-lived.

E The historian Brian Cowan has argued that the rise of the English coffee house should be understood not merely as a curiosity of social history but as part of the broader emergence of what other historians have called the public sphere. In this view, coffee houses provided a relatively new kind of space in which strangers from different social ranks could meet on broadly equal terms, exchange information, and form opinions on matters of public concern, in many cases for the price of a single cup. The opinions formed in such venues, often discussed alongside newspapers and pamphlets, helped to shape what historians have described as a public mood capable of constraining the actions of governments.

F The economic functions of coffee houses, although less frequently celebrated, were no less significant. Edward Lloyd's coffee house, opened on Tower Street in London around 1688, became a regular meeting place for merchants, ship captains, and insurers, and is regarded as the institutional ancestor of Lloyd's of London, today one of the world's largest insurance markets. Jonathan's coffee house in Change Alley, near the Royal Exchange, hosted the first informal trading in joint-stock shares and has been described as a precursor of the London Stock Exchange. Similar coffee houses in Amsterdam and Hamburg played comparable roles.

G Not all contemporaries welcomed the new institution. Critics, including a number of London women authors who in 1674 issued a pamphlet known as the Women's Petition Against Coffee, attacked the drink as bitter, foreign, and conducive to neglect of domestic life. Other writers warned that coffee houses encouraged idleness or seditious talk. Although such critiques are now often read as comic, they captured genuine anxieties about how a beverage and an associated social space were reshaping daily routines. Historians broadly note, however, that despite the rhetoric, women were in fact involved in coffee-house culture, often as proprietors or behind-the-scenes managers of household-run establishments.

H By the late eighteenth century, the European coffee house had begun to lose some of its central political and intellectual function. Newspapers and journals were increasingly delivered to homes and to private subscription libraries, gentlemen's clubs offered exclusive spaces for political discussion, and stock exchanges relocated from coffee houses to purpose-built buildings. The familiar twentieth-century coffee shop, with its emphasis on rapid service and individual consumption, retains only a faint echo of these earlier functions. Yet the legacy of the seventeenth-century coffee house remains visible, in many historians' view, in the institutions of insurance, finance, and public opinion that trace their origins back to its long communal tables.

A Vertical farming, defined as the production of crops in stacked layers within a controlled indoor environment, has attracted growing attention as both a technological project and a possible response to long-term pressures on food systems. Conventional field agriculture is responsible for a substantial share of global freshwater use, land conversion, and greenhouse gas emissions, and is widely considered increasingly vulnerable to disruption from heat waves and droughts. Proponents argue that producing leafy greens, herbs, and certain fruiting crops inside warehouses and disused industrial buildings could reduce these pressures while bringing fresh produce closer to urban consumers. Sceptics generally caution that the costs of moving crops indoors may significantly limit the contribution vertical farms can make.

B The basic technical principles of vertical farming are not new. Hydroponic cultivation, in which plants grow with their roots suspended in nutrient-rich water rather than in soil, has been practised for more than a century, and aeroponic systems, in which roots are misted with nutrient solution in air, have been used by NASA in space-flight research. What is novel is the scale at which these techniques are now being deployed and the degree to which they have been integrated with light-emitting diode illumination, climate control, and software systems that automate routine cultivation tasks.

C Among the most frequently cited advantages of vertical farming is its capacity to use water with extraordinary efficiency. Because evaporation from the indoor environment is tightly controlled and unused water is recirculated, well-designed vertical farms reportedly use between 70 and 95 percent less water per unit of harvested crop than equivalent open-field production. Land use is similarly reduced: by stacking growing surfaces vertically and operating year-round, a single building can replicate the seasonal yield of many hectares. Because crops are isolated from pests and adverse weather, pesticide use can be minimised or eliminated.

D The fundamental challenge of vertical farming, in many engineers' view, lies in its appetite for electricity. Indoor crops generally require artificial illumination for many hours each day, and even the most efficient LED systems consume considerable amounts of energy. A 2020 review estimated that producing a kilogram of leafy greens in a typical vertical farm required between five and ten times more electricity than the equivalent open-field production once differences in regional climate were taken into account. Where electricity is generated largely from fossil fuels, this elevated demand can offset much of the climate benefit gained through reduced land use and transport. Vertical farms in regions with predominantly renewable electricity, such as parts of the Nordic countries or the Pacific Northwest of the United States, generally face a markedly more favourable balance.

E Crop selection has emerged as a critical determinant of commercial viability. Leafy greens such as lettuce, spinach, and rocket are well suited to vertical farming because they grow quickly, command relatively high prices per kilogram, and need only modest amounts of light. Herbs and microgreens generally share similar characteristics. By contrast, staple crops such as wheat, rice, maize, and potatoes are widely considered unsuitable for vertical production: they require very high light intensities for long periods, are bulky and inexpensive per kilogram, and are already produced at very large scales in open fields. Most commercial vertical farms operating today reportedly concentrate on leafy greens, salad mixes, and culinary herbs.

F Some recent technological developments have begun to expand the range of crops that may eventually be viable indoors. Researchers at several universities have reported successful indoor cultivation of strawberries, tomatoes, and bell peppers using carefully tuned LED spectra and managed pollination by bumblebees released into the growing environment. Other groups are exploring rapid breeding programmes that combine genomic analysis with controlled indoor environments to develop varieties optimised for vertical production, with traits such as shorter stature, faster maturation, and high yield under specific lighting regimes.

G The economic record of large commercial vertical farms has so far been mixed. A wave of well-funded ventures launched in the late 2010s in the United States, Europe, and East Asia attracted substantial venture capital on the strength of projections that combined automation and scaling would steadily reduce unit costs. By the early 2020s, however, several of these companies had closed facilities, reduced staff, or restructured under bankruptcy protection, citing higher than expected energy costs, slow adoption by retailers, and the difficulty of competing with conventional produce on price.

H Notwithstanding these setbacks, advocates of vertical farming reportedly continue to argue that the long-term case for the technology remains strong. Climate models broadly project increasing instability in conventional crop yields under continued warming, particularly in regions such as the Mediterranean basin and parts of South Asia. Vertical farms, by contrast, are largely insulated from outdoor weather and can produce reliably year-round.

I The future of vertical farming, in many analysts' view, is therefore likely to be neither the revolutionary transformation of food production sometimes promised by its enthusiasts nor the marginal experiment occasionally dismissed by its critics. A more realistic outcome, broadly consistent with current evidence, is the gradual emergence of an industry concentrated in high-value crops, in regions with abundant renewable electricity, and in cities where freshness and supply-chain reliability are valued. Vertical farms, in this view, will complement rather than replace open-field agriculture, and their contribution to global food supply will continue to depend on parallel advances in plant breeding, energy systems, and urban planning.