【推荐3】At age 10, McCullough got a glimpse of her dream job. It sparkled in the eyes of the Packard Children’s nurses who cared for her brother Matthew, who had brain cancer. As a child, McCullough spent hours at her brother’s bedside. “I looked up to the nurses. I found their unconditional commitment to my brother’s care remarkable,” McCullough says.

As a young girl, McCullough practiced nursing by caring for her brother, a desire born out of her intense love for him. She would rub his back, bring him drinks, and even help adjust his lines. She was a natural. Her parents said that she was very caring and always put people first from a young age.

When Matthew passed away, McCullough became even more committed to becoming a nurse. She took steps through the years to make her dream come true. In high school, she volunteered at cancer centers and hospitals. “My becoming a nurse is 100% in honor of Matt. I felt the need to channel my grief and turn that tragic moment into something positive,” McCullough says.

Over time, McCullough realized that she didn’t just want to be a nurse. She wanted to be a pediatric oncology (儿科肿瘤) nurse at Packard Children’s. McCullough wanted to give back to the hospital that had done so much for her brother.

Despite feeling like school never came easy, McCullough persisted (坚持) and got into a respected nursing school. She feels like she worked 10 times harder than other nursing students at the university. She traded going out and spending time with friends for the library.

In college, each step brought McCullough closer to her dream. She worked as a nursing assistant at Stanford Health Care for adults with cancer. Then, she transferred to Packard Children’s and worked as a nursing assistant in the Pediatric Transplant Center.

Today, She’s a nurse on the same unit that cared for her brother years ago. She is one of those nurses she admired so much as a child. She finds the time, even on very busy days, to truly be there for patients and families to make them feel loved and welcomed.

【推荐1】Electric vehicles (EVs) have long been advertised as environmentally friendly vehicles. This is true, to some extent. EVs do not emit any carbon dioxide into the environment, unlike conventional cars.

But scientists foresee a new problem. Cars run on batteries, and electric cars are no different. So once the battery reaches the end of its useful life, what will be done with it?

As the number of electric vehicles in use increases greatly, scientists must discover an effective recycling method for EV batteries.

While electric cars and gas-powered cars essentially function in the same way, a major difference between the two is their batteries.

Electric vehicles use lithium-ion (锂离子) batteries, which are larger and heavier than a non-EV car’s lead-acid (铅酸) batteries. Instead of fuel, EVs rely directly on their batteries for a source of energy.

When charging, electricity triggers (引起) chemical changes within the battery. On the road, the chemical changes are converted into electricity, thus powering the car. The continuous charge-discharge process reduces the charge (电荷) the battery can hold. Thus, the distance and time between the car’s next charging session decreases.

The battery’s average lifespan ranges from five to eight years to 10-20 at most, so drivers will need to replace EV batteries many times in the car’s life.

A major issue with EV batteries is the inconvenience they pose during dismantling (拆卸). EV batteries are made up of several hundred lithium-ion cells. Each cell contains risky materials and must be dismantled individually. If not dismantled correctly, the battery cells may even explode.

Additionally, recycling methods that do exist for these batteries are energy- and cost-intensive. In fact, in the European Union and the US, lithium-ion battery recycling rates are only 5%.

Companies are trying to find solutions. Nissan, a car company, is reusing their electric car batteries in automated guided vehicles in their factories. These vehicles deliver car parts to workers. Volkswagen also uses its batteries like Nissan, but also recently opened its first recycling plant.

【推荐2】This past July was the hottest recorded month in human history. Heat waves brake temperature records worldwide. It’s more than just a matter of sweaty discomfort. As climate change worsens, access to artificially cooled spaces is rapidly becoming a health necessity.

Yet standard air-conditioning systems leave us trapped in a negative feedback cycle: the hotter it is, the more people use the air condition er and the more energy is consumed as a result. Cooling is the fastest-growing single source of energy use in buildings, according to the International Energy Agency. Breaking the cycle requires new innovations that will help bring cooler air to more people with less environmental impact.

Standard air-conditioning systems cool and dehumidify (除湿) through a relatively inefficient mechanism: in order to condense (冷凝) water out of the air, they overcool that air past the point of comfort. Many new designs therefore separate the dehumidification and cooling processes, which avoids the need to overcool. For example, some new air conditioner designs pull water from the air with desiccant (干燥剂) materials. The dried air can then be cooled to a more reasonable temperature. Massachusetts-based start-up Transaera claims that the system it is developing could use 35 percent less energy than the average standard air-conditioning unit.

However, the gains in efficiency might not help us get rid of the impact of air-conditioning. “It won’t work to simply replace every existing air conditioner with a better model and call it a day,” says Nicole Miranda, an engineer at the University of Oxford. “Instead, a truly coder future will have to employ other strategies. It’s critical to bring greenery and water bodies into cities to take advantage of natural airflow.”

“Cooling is a challenge involving many aspects,” says Sneha Sachar, an expert at the nonprofit organization ClimateWorks. “There isn’t one strategy or one answer. We need a combination of better buildings and cities, better technologies and a better understanding that the true cost of air-conditioning extends beyond electric bills.”