1,3,3,3-Tetrafluoropropene (HFO-1234ze(E), R-1234ze) is a hydrofluoroolefin. It was developed as a "fourth generation" refrigerant to replace fluids as R-134a and as a blowing agent for foam and aerosol applications. The use of R-134a is being phased out because of its high global-warming potential. HFO-1234ze(E) has zero ozone-depletion potential (ODP=0), a very low global-warming potential (GWP < 1 ), even lower than CO2, and it is classified by ANSI/ASHRAE as class A2L refrigerant (lower flammability and lower toxicity).

Wavel Ramkalawan (born 15 March 1959) is a Seychellois politician and Anglican priest who has been serving as the President of the Republic of Seychelles since 26 October 2020. Ramkalawan was an opposition MP from 1993 to 2011 and 2016 to 2020. He also served as the Leader of the Opposition from 1998 to 2011 and 2016 to 2020. On 25 October 2020, Ramkalawan won the presidential election, the first such victory for an opposition candidate since independence.

Renewable energy sources such as solar, wind, tidal, hydro, biomass, and geothermal have become significant sectors of the energy market. The rapid growth of these sources in the 21st century has been prompted by increasing costs of fossil fuels as well as their environmental impact issues that significantly lowered their use. Copper plays an important role in these renewable energy systems. Copper usage averages up to five times more in renewable energy systems than in traditional power generation, such as fossil fuel and nuclear power plants. Since copper is an excellent thermal and electrical conductor among the engineering metals (second only to silver), power systems that utilize copper generate and transmit energy with high efficiency and with minimum environmental impacts. When choosing electrical conductors, facility planners and engineers factor capital investment costs of the materials against operational savings due to their electrical energy efficiencies over their useful lives, plus maintenance costs. Copper often fares well in these calculations. One pertinent factor, called "copper usage intensity,” is a measure of the quantity of copper necessary to install one megawatt of new power-generating capacity. When planning for a new renewable power facility, engineers and product specifiers seek to avoid supply shortages of selected conductor materials. According to the United States Geological Survey, in-ground copper reserves have increased more than 700% since 1950, from almost 100 million tonnes to 720 million tonnes today, despite the fact that world refined usage has more than tripled in the last 50 years. Copper resources are estimated to exceed 5,000 million tonnes. Bolstering the annual supply is the fact that more than 30 percent of copper installed during the last decade came from recycled sources. Regarding the sustainability of renewable energy systems, it is worthy to note that in addition to copper's high electrical and thermal conductivity, its recycling rate is higher than any other metal. This article discusses the role of copper in various renewable energy generation systems.

Salih Zeki Bey (1864, Istanbul – 1921, Istanbul) was an Ottoman mathematician, astronomer and the founder of the mathematics, physics, and astronomy departments of Istanbul University. He was sent by the Post and Telegraph Ministry to study electrical engineering at the École Polytechnique in Paris. He returned to Istanbul in 1887 and started working at the Ministry as an electrical engineer and inspector.He was appointed as the director of the state observatory (Ottoman Turkish: رصدخانه‌يي امیره‎) (now Kandilli Observatory) after Coumbary in 1895.In 1912, he became Under Secretary of the Ministry of Education and in 1913 the president of Istanbul University. In 1917, he resigned as the president but continued teaching at the University in the Faculty of Sciences until his death.

Leading lady is a term often applied to the leading actress in the performance if her character is the protagonist. It is also an informal term for the actress who plays a secondary lead, usually a love interest, to the leading actor in a film or play. A leading lady can also be an actress of renown. For example, Lynn Fontanne and Helen Hayes were both referred to as the "leading lady of the theatre" in their time. Similarly, Mary Pickford was called the "leading lady" of the cinema. The term has been applied to an actress who is often associated with one particular actor. For example, Olivia de Havilland was Errol Flynn's leading lady in several films, Katharine Hepburn had a similar association with Spencer Tracy, Lauren Bacall with Humphrey Bogart, and Maureen O'Hara with John Wayne. A leading lady is also an actress who is typecast in romantic supporting roles. The term can also be used collectively; for example, the phrase "Hollywood's leading ladies" can be used to refer to a group of notable, famous, or popular actresses. Modern day leading ladies include: Amy Adams, Jennifer Aniston, Morena Baccarin, Kathy Bates, Candice Bergen, Cate Blanchett, Emily Blunt, Julie Bowen, Sandra Bullock, Carol Burnett, Paget Brewster, Jennifer Carpenter, AJ Cook, Glenn Close, Marion Cotillard, Courteney Cox, Penélope Cruz, Kaley Cuoco, Jamie Lee Curtis, Claire Danes, Judi Dench, Laura Dern, Cameron Diaz, Anna Faris, Tina Fey, Jane Fonda, Jodie Foster, Gal Gadot, Marla Gibbs, Lola Glaudini, Judy Greer, Anna Gunn, Jackee Harry, Anne Hathaway, Anne Heche, Taraji P. Henson, Bryce Dallas Howard, Isabelle Huppert, Kate Hudson, Allison Janney, Scarlett Johansson, Angelina Jolie, Diane Keaton, Jessica Lange, Brie Larson, Téa Leoni, Jane Lynch, Carol Kane, Nicole Kidman, Jane Krakowski, Lisa Kudrow and Jennifer Lawrence. Others include: Megan Mullally, Margo Martindale, Marlee Matlin, Frances McDormand, Melissa McCarthy, Kate McKinnon, Shirley McLaine, Bette Midler, Helen Mirren, Julianne Moore, Rita Moreno, Justina Machado, Julia Louis-Dreyfus, Kathy Najimy, Cynthia Nixon, Lupita Nyong'o, Sandra Oh, Catherine O'Hara, Sarah Jessica Parker, Michelle Pfeiffer, Amy Poehler, Natalie Portman, Judy Reyes, Margot Robbie, Emma Roberts, Julia Roberts, Saoirse Ronan, Gwyneth Paltrow, Susan Sarandon, Octavia Spencer, Mary Steenburgen, Wanda Sykes, Emma Stone, Elle Fanning, Hailee Steinfeld, Anya Taylor-Joy, Jeanne Tripplehorn, Aisha Tyler, Meryl Streep, Kristen Stewart, Charlize Theron, Alicia Vikander, Kerry Washington, Emma Watson, Kristen Wigg, Kate Winslet, Reese Witherspoon, and Renée Zellweger. Minnie Mouse, an anthropomorphic animated character, has been the most notable and most successful cartoon leading lady for The Walt Disney Company over the generations, who mostly portrays the secondary lead roles to her respective boyfriend and the company's mascot Mickey Mouse.