Millions of musicians around the world-from school groups to rock banks to professional symphony orchestras-practice, perform, and travel regularly, (1) meaning they must make arrangements for their instruments to travel with them. Guitars need new frets, clarinets need rusty keys cleaned or replaced, and pianos need to be tuned. (2) For comprehensive maintenance and (3) potent repairs, musicians need musical instrument technicians, trained professionals with an expert knowledge of both mechanics and music.  Becoming a musical instrument technician requires dedication.

It requires (4) dedication to learning the intricacies of instruments. Many technicians are (5) a musician themselves, and some also have professional backgrounds in business, marketing, or engineering; they often attend technical schools or do apprenticeships with experienced technicians. Though technicians generally specialize in one or two instruments, they need to have extensive knowledge of various instrument types and brands, what kinds of routine maintenance need to be done on them, typical problems that occurs, and how to repair damage. If an instrument is not performing to a musician's standards, a technician needs to be able to diagnose the problem and (6) than advice the client and perform repairs. (7) Likewise, a trumpet might not be functioning properly because the valves have become sticky, the joints have developed air (8) leaks, or the metal parts have been dented. 

[l] Musical instrument technicians are needed in a variety of settings. [2] Large instrument manufacturers such as Steinway, for example, (9) hires instrument technicians to work at their factories and retail stores. [3] Some technicians get to work at concert venues and music festivals, setting up instruments and keeping equipment in optimal shape. [4] Tom Weber, a concert technician for forty years, has traveled extensively and maintained guitars for acts such as Van Halen and Reba McEntire, restringing guitars before each show. [5] He has "never had an artist break a string onstage," he says. [6] After obtaining her certification in piano tuning and technology, Michelle Lamm worked as a piano repair intern and then decided to start her own business, Michelle's Melody Fine Piano Tuning and Repair. [7] She travels to homes and businesses fixing pianos; for one job, she even helped refurbish a forty-year-old grand piano. (10)

Though considerable study and practice are necessary to join the field, musical instrument technicians perform a vital service for musicians and their audiences. Live performances, studio sessions, and the careers of individual (11) musicians all rely on instrument technicians to keep equipment in top shape and the music playing on.

Digital technology has expanded opportunities for creative expression, (12) no matter the art form: the spread of software that can be used to cut parts from different songs and paste them together (13) have spurred the creation of a music genre known as remix, or mashup. Opponents of this art form maintain that remix artists violate copyright law because they borrow material from protected works to the financial (14) detriment of the original artist. However, remixing is a culturally valuable art form that often benefits the artist whose material is used, and its designation as copyright infringement warrants reconsideration. 

[l] Gregg Gillis, aka "Girl Talk," has been involved in debates about the legality of remix art for more than a decade. [2] Using only a laptop, Gillis collects samples from songs ranging from rock ballads to hip-hop, cuts them to different lengths (some as short as a single drum beat) and (15) arranging them into a different form. [3] Although his critically acclaimed 2006 album Night Ripper consists of hundreds of samples from different artists, Gillis believes his songs are original because (16) they, "recontexualize the source material into a new whole." [ 4] His music provides new ways of relating to the Old-listeners may revisit a song they had previously dismissed when they find themselves enjoying it mixed with a song they love-so he believes his sampling qualifies as "fair use," a (17) legally permissible borrowing of copyrighted material for a transformative purpose. (18)

For material to qualify as fair use, however, the borrower must not only transform the meaning of the original but also (19) borrow only a small part of it. If using a sample hurts the sale of a copyrighted work, then it does not qualify as fair use. In such cases, the law requires the borrower to obtain a license from the copyright owner, a process that legal scholar Lawrence Lessig describes as prohibitively costly and cumbersome for independent artists. Gillis, though, contends that his work does not hurt but rather promotes interest in the source material. A Girl Talk song that features the Notorious B.I.G. and Elton John might send listeners running to hear more from the Brooklyn rapper and the British songsmith. 

Although it is important (20) protecting artists by not allowing complete copies of their work to be distributed without permission, remix art is not a mere verbatim copy but a repurposing of source materials that makes (21) it's audience think about how one piece of art fits into the broader cultural landscape. The law should encourage, not inhibit, this creative interaction with culture, especially when the remix (22) is wildly popular.

Motivating people to engage in socially beneficial behaviors, such as conserving energy (23) resources—is a challenge. Many assume that the only way to encourage such engagement is through financial rewards or penalties. Harvard economist Erez Y oeli and his colleagues have learned, however, that reputation is a strong incentive for making choices that aid the public (24) good in ways that benefit everyone. Such choices might entail short-term costs, but they carry a potential long-term benefit: if other people see that an individual is willing to sacrifice personal convenience for the sake of the greater good, they might be inclined to sacrifice their own convenience for that individual's benefit someday. 

Yoeli's team of researchers (25) theorized about the historical importance of reputation by comparing different sign-up methods for a voluntary program aimed at preventing domestic power failures. For the program, participants (26) okayed the installation of a device in their homes that limited the use of an air-conditioning unit when demand for energy was highest. Researchers (27) place a sign-up sheet in a public place in housing developments and apartment buildings. Some residents were asked to enroll using an anonymous code; others were asked to use their names, which made the choice researchers found that the observable sign-up strategy was three times more effective (28) than the anonymous one. They also determined that observable sign-up was considerably more effective than offering a $25 incentive to enroll. Even though people who enrolled in the program believed that they would suffer an inconvenience—less control over home temperature at certain times of the day—(29) but the publicity of the choice to sign up was incentive enough for many to accept the inconvenience because it made others aware that they were doing their part to prevent blackouts. 

(30) Since reputation sometimes fails to promote good deeds, the strength of its influence varies based on the likeliness of one's participation being noticed. For example, in Yoeli's study, sign-up rates were affected by the observability of the location where the sheet was placed. In residences (31) where sign-up sheets were posted in high-activity public spaces, like a shared mail area, anonymous enrollment was 4.8 percent and observable enrollment was 11.4 percent, a difference of 6.6 percentage points. (32) The more observable the community-minded action, the more likely (33) those are to benefit the individual's reputation. On the other hand, says Yoeli's coauthor David Rand, if an action is not observable, "then there's no problem with not participating."

Although it has been known for (34) centuries that plant's absorb carbon dioxide (CO2), a gas that animals exhale, it was not until the 1940s that scientists understood how plants use this gas during photosynthesis, the process by which plants convert light energy into chemical energy that they store in the form of sugars. The discovery was made through a series of experiments conducted by the (35) chemists Melvin Calvin and Andrew Benson. Key to their early experiments was a technique called carbon labeling, which allowed Calvin and Benson to determine whether plants need light exposure while they break down CO2 to use its carbon atoms to construct sugars. The scientists decided to use a variation of CO2 in which the ordinary carbon atoms would be replaced with carbon-14 (14C), a radioactive isotope of carbon that would function as a radiotracer: plants would absorb and metabolize the 14CO2 as though (36) they are regular CO2, and then the researchers would track the 14C to determine what the plant had done with it. 

(37)  One sample was stored in the dark for eight hours; the air in that sample's container had CO2. The other sample was exposed to bright light for one hour; (38) this sample was considered to be "preilluminated."  After removing the air from both containers and placing them in the dark, (39) the samples were exposed to the CO2 by the researchers. Five minutes later, the algae samples were killed to prevent further metabolic activity, and their molecular contents were examined. 

The sample initially stored in the dark container had produced almost no sugars made with the traceable 14C, indicating that the algae hadn't metabolized the 14CO2. (40) Finally, the algae had not been able to photosynthesize. But the algae in the other sample, which had been initially exposed to the one hour of light, produced measurable (41) concentrations of radioactive sugars. (42) In this sample, carbon atoms from the ¹⁴ C02 had been used to construct the frame of the sugar glucose (C6H1206 ). Oxygen (0) and hydrogen  (H) atoms from another molecule were also used. During its CO2 starved exposure to light, the algae had stored the light's (43) energy, and then later using that stored energy to construct sugars in the dark. (44)

Through this experiment, Calvin and Benson were able to conclude that light was not directly responsible for breaking C02's bonds. Something else in the plant did that. The chemists spent several years identifying that enzyme (rubisco), and their research helped elucidate the rest of the chemical cycle that results in the generation of glucose during photosynthesis.