Climbing Without Ropes

    The popular image of the mountain climber is of a person carefully climbing a steep cliff with a network of safety ropes, but it is not the only kind. Many climbers now enjoy bouldering. It's more accessible and better for the environment.

    Here is an example of a climber addressing a bouldering problem.

    Figure 1: The climber has two routes she could take, one to the left and one to the right. The left one appears easier because it has a jug within easy reach, but look what happens if she chooses that direction. She gets stuck on the rock and has to go back down. Sometimes that is even more difficult than going up.

    Figure 2: The climber takes the one to the right this time. Using a foothold and placing her right hand in a crimp, she is able to lift herself up and locate other handholds. After only a few moves, she is able to throw her leg over the top of the boulder and pull herself up.

    Parents can cut the chances of their children getting fat simply by keeping them longer at table. Just three minutes extra at a family mealtime could help prevent child obesity. Research found that among poor families, the extra minutes at mealtimes made great improvement of a normal weight for the youth. The factors are likely to be communication and the importance of a scheduled mealtime.

    Dr Barbara Fiese said, “Children, whose families have a 20-minute meal over four times a week, weigh less than kids who leave the table after 15 to 17 minutes. Over time, those extra minutes per meal add up and become really powerful.”

    The researchers studied 200 family mealtimes, testing the effects of factors and mealtime behavior of families with children in primary school. They found that families, who said that shared mealtimes were an important part of family life and had special meaning for them, were less likely to have an obese child. Similarly, families, who talked more together and interacted more positively during the meal, were more likely to have healthy-weight children.

    Teaching low-income families how to make the most of family mealtimes was a wise idea. Dr Fiese said, “This is something we can target and teach.” She added, “It's also important to recognize the increasing differences of families and their sometimes complex living arrangements that may challenge their abilities to plan ahead and arrange a single time to communicate with each other.”

    Families in poorer US neighborhoods faced a lot of problems, including poor access to healthy food. But even so, regular high quality family mealtimes made a difference to the children's weight. Dr Fiese said, “Three to four extra minutes per meal will make a healthy weight more possible.”

    How many times have you come back and felt terribly tired, feeling like your head is going to explode? Sounds familiar, right? Well, there are several ways to reduce the frequency of headaches, and those are: eating balanced diet through the day, making sure your body is well hydrated (保持身体水分);getting some exercise to remove the negative energy, like helping yourself with a short massage (按摩)on your head. However, preparing an easy recipe will instantly put a smile on your face after your workday.

    You will need these simple ingredients (配料)to prepare the magical drink which will stop your headache: Lemon juice; 2 teaspoons of salt (preferably high quality salt); 1 cup of water.

    Directions:

    Squeeze 2 lemons. Pour the lemon juice into a cup and add 2 teaspoons of salt. Mix the two ingredients. Add a cup of water to the content. Drink the mixture quickly.

    How will this drink work and what are the benefits of its ingredients?

    Salt: Here is what salt does for your body: regulates your blood sugar, balances the sugar levels; benefits nerve cells for communication and information processing; obtains acidity from your body's cells, especially brain cells; works as a strong anti-stress element for the body; adds energy in your body's cells.

    Lemon Juice: This excellent juice, full of vitamin C and anti-poisons, will release all poisonous substances from your body and give you a sense of lightness. Here's how the lemon will help you ease your headache and maintain well-being to your whole body: balances the pH levels in your body; protects your immune system; nourishes your brain and nerve cells; reduces inflammation (炎症)in your whole body (the headache is a type of inflammation, so the lemon juice fights against it).

    Water：

    Water is important for hydrating your whole body, including your head. Many of your daily headaches may be caused by dehydration (脱水), so keep in mind that you should drink plenty of water throughout the day.

    American high school students are terrible writers, and one education reform group thinks it has an answer: robots. Or, more accurately, robot-readers—computers programmed to scan students' essays and spit out a grade.

    Mark Shermis, professor of the College of Education at the University of Akron, is helping to hold a contest, set up by the William and Flora Hewlett Foundation (WFHF), which promises $ 100,000 in prize money to programmers who write the best automated grading software. "If you're a high school teacher and you give a writing task, you're walking home with 150 essays," Shermis said. "You're going to need some help."

    Automated essay grading was first proposed in the 1960s, but computers back then were not up to the task. In the late 1990s, as technology improved, several textbooks and testing companies jumped into the field. Today, computers are used to grade essays on South Dakota's student writing assessments and a handful of other exams, including the TOEFL test of English fluency, taken by foreign students.

    The Hewlett contest aims to show that computers can grade as well as English teachers—only much more quickly and without all that depressing red ink. "Automated essay scoring is objective," Shermis said. "And it can be done immediately. If students finish an essay at 10 pm, they will get a result at 10: 01 pm."

    Take, for instance, the Intelligent Essay Assessor, a web-based tool marketed by Pearson Education, Inc. Within seconds, it can analyze an essay for spelling, grammar, organization, and help students to make revisions. The program scans for key words and analyzes semantic (语义的) patterns, and Pearson claims that it can understand the meaning of text much the same as a human reader.

On a recent Wednesday, archaeologists announced a groundbreaking discovery that challenges our understanding of early human capabilities. They have unearthed what is believed to be the oldest wooden structure ever found, dating back nearly half a million years. This discovery at Kalambo Falls in northern Zambia, near the border with Tanzania, suggests that our ancestors were more technologically advanced than previously thought.

The wooden structure, which is exceptionally well-preserved, dates back at least 476,000 years. This timeline predates the emergence of Homo sapiens, as detailed in a study published in the journal Nature. The wood shows evidence of having been cut and shaped using stone tools, indicating a level of craftsmanship that was not previously attributed to these early humans.

The structure, which is thought to have functioned as a walkway or platform elevated above the seasonally wet ground, demonstrates a purposeful construction technique. A collection of wooden tools, including a wedge and a digging stick, were also found at the site, further supporting the idea of a developed woodworking tradition.

Larry Barham, an archaeologist at the University of Liverpool and the lead author of the study, described the structure as involving "the intentional shaping of two trees to create a framework of two interlocking supports." A notch was cut into one log, and another tree was shaped to fit through this notch, providing stability to the structure.

The use of wood by early humans was already known, but it was typically associated with basic tasks such as starting fires or hunting. However, the discovery at Kalambo Falls indicates a more sophisticated application of woodworking skills. Barham explained, "The structure involves the intentional shaping of two trees to create a framework of two interlocking supports," which required a level of planning and execution that suggests a higher cognitive ability.

The preservation of the wooden structure is remarkable, given that wood typically decays over time, leaving little trace for archaeologists to study. The high water levels at Kalambo Falls are believed to have played a crucial role in preserving the structure for centuries.

These findings from Kalambo Falls not only provide evidence of an early human ability to manipulate their environment but also suggest a more complex cognitive capacity among these early humans than what has been inferred from stone tools alone. Barham concluded, "The finds from Kalambo Falls indicate that these earlier humans, like Homo sapiens, had the capacity to alter their surroundings, creating a built environment." This discovery underscores the need to reassess our understanding of early human technological and cognitive development.