Some fundamental interactions of matter turn out to be fundamentally different than thought, say Stanford researchers
Collisions have consequences. Everyone knows that. Whether it's between trains, planes, automobiles or atoms, there are always repercussions. But while macroscale collisions may have the most obvious effects—mangled steel, bruised flesh—sometimes it is the tiniest collisions that have the most resounding repercussions.
Such may be the case with the results of new experimental research on collisions between a single hydrogen atom and a lone molecule of deuterium—the smallest atom and one of the smallest molecules, respectively—conducted by a team led by Richard Zare, a professor of chemistry at Stanford University.
When an atom collides with a molecule, traditional wisdom said the atom had to strike one end of the molecule hard to deliver energy to it. People thought a glancing blow from an atom would be useless in terms of energy transfer, but that turns out not to be the case, according to the researchers.
"We have a new understanding of how energy can be transferred in collisions at the molecular scale," said Zare, senior author of a paper presenting the results in the July 3 issue of Nature.
Every atom or molecule, even if it has no charge, has electrostatic forces around it—sort of like the magnetic field of the Earth. Those chemical forces exert a pull on any other atom or molecule within range, trying to form a chemical bond.
What Zare and his team found is that a speeding hydrogen atom does not have to score a direct hit on a deuterium molecule, a form of molecular hydrogen made up of two heavy isotopes of hydrogen, to set the molecule vibrating. It only needs to pass closely enough to exert its tiny chemical force on the molecule. Vibrating molecules matter because they are more energized, making them more reactive. Thus, energy transfer effectively softens them up for future reactions.
"This has changed a very simple idea that we cherished—that to make a molecule highly vibrationally excited, you basically had to crush it, squeeze it, hit it over the head. Compress some bond and the molecule would snap back," Zare said. "We found quite the opposite."
One could compare it to the difference between a punch in the stomach and a caress on the cheek. Both can set the senses tingling, but in very different fashions.
Zare's team discovered that as a hydrogen atom passed close to a deuterium molecule, the chemical forces tugged on the nearest of the deuterium atoms in the molecule, pulling it away from the other deuterium atom. But if the tug was not strong enough to break the two deuterium atoms apart, as the hydrogen atom moved farther away its hold on the deuterium atom would weaken. The deuterium atom would eventually slip from its grip and snap back toward the other deuterium atom, initiating an oscillation, or vibration.
"What we are really seeing is the result of a frustrated chemical reaction," Zare said. "The molecule wants to react. It just didn't get into the right position with the right conditions so that it could react."
Zare went on to picture this process as follows: "The deuterium molecule is in a happily married state until the hydrogen atom flies by and attracts the nearest deuterium atom. This deuterium atom in the middle is in a giant tug of war. It is being fought over by two lovers, two highly similar atoms that are both attracted to the middle deuterium atom. This affair is a love triangle. In energy transfer, the original spouse wins out. The middle deuterium atom decides not to stray and rebounds to the other deuterium atom—its first love—setting both to vibrate rapidly."
The new findings may have ramifications for understanding what happens in any chemical reaction, in addition to interactions between chemicals that do not result in a reaction but instead result in energy transfer. So far, one instance has been discovered, but Zare believes that this behavior is likely to be found in many other collision systems.
"This is very fundamental stuff as to what happens in transformations of matter from one state to another," Zare said. "It's very fundamental chemistry."
Comparing the ramifications of the new findings to a ripple spreading out from a pebble dropped into a pond, Zare said, "Maybe this will be the sound of one hand clapping, if the ripple doesn't go anywhere. Taken together, the only way we advance is making these ripples and following them as they spread outward."
Zare's group did the experiments that revealed the energy transfer occurring during "soft" collisions between the hydrogen atom and the deuterium molecule by using techniques and equipment for measuring the molecular interactions that had previously been developed in his laboratory. The experimental work is a major portion of the doctoral thesis of his graduate student Noah T. Goldberg, who was assisted in these measurements by Jianyang Zhang, a postdoctoral researcher, and graduate student Daniel J. Miller. The theoretical calculations that provided the model used to explain the observations is the result of work done by co-authors Stuart Greaves of the University of Bristol and Eckart Wrede of the University of Durham, both in Britain.
The research done at Stanford was funded by the National Science Foundation. The research done in Britain was funded by the Engineering and Physical Sciences Research Council.
For decades, teachers have been paid according to seniority and educational degree level; that’s beginning to change.
Lately, policymakers and education advocates have been experimenting with new tools for improving American public education, from adopting radical new pedagogical techniques to employing artificial intelligence-based adaptive learning programs. However, one area stands out as so fundamental yet so resistant to change that, until recently, many activists had given up on it: teacher compensation reform.
Perhaps the most contentious area of compensation reform is pay for performance (PFP) which involves paying teachers more if they drive better student outcomes. It upends the traditional single salary schedule model that bases teacher pay entirely on seniority and education level. Reform advocates argue that the prospect of higher pay motivates teachers to improve, just as bonuses are widely used in the private sector to encourage workers to be more productive. While the idea that higher pay will motivate better work seems reasonable, the evidence is limited and often inconclusive: research tends to show that paying teachers more improves student outcomes, but studies looking strictly at the impact of bonus structures often have conflicting results.
Advocates for continued use of the single salary schedule argue that performance-based payments are ineffective because accurately measuring teacher performance is nearly impossible and even if it were not, PFP creates a toxic, competitive school atmosphere. However, recent approaches to PFP have sought to address these issues, and policymakers are taking note.
One of the most innovative and high-profile approaches to measuring teacher performance was brought to the public’s attention in 2009 by Michelle Rhee, former superintendent of the District of Columbia Public Schools. Her measurement tool, developed by research firm Mathematica and Harvard professor Thomas Kane as part of a larger framework for teacher accountability called “IMPACT,” relied on a fixed effects multivariate regression to measure teachers’ “value-added” effect on student test scores. Unlike traditional measurement systems, the IMPACT tool accounted for things outside a teacher’s control like student intelligence (measured by previous test performances), family socioeconomic status, and English proficiency. This meant that only recent “shocks” affecting a student’s testing capability — like a newly-developed cognitive impairment — could unfairly affect a teacher’s IMPACT score. While shocks do happen, they’re relatively rare and distributed across classrooms.
In addition to Washington, DC, a number of other public school districts (e.g., Chicago) and states (e.g., Florida and Ohio) have adopted value-added measures as part of teacher evaluation systems. However, despite the quantitative rigor and objective nature of effective value-added modeling compared to more subjective evaluation methods, it is yet to be widely adopted. Importantly, its wide adoption could facilitate increased use of effective PFP as a way to retain strong teachers and motivate poor and average performers to improve.
Meanwhile, to address the ‘competitive environment’ concern of opponents to PFP, bonus models have been adapted to apply not just to individual teachers, but also wider groups — like teacher teams and entire schools — to encourage collaboration. Some bonus models have even included school support staff as potential beneficiaries of improved student outcomes.
PFP is not always possible given the strength of teacher union opposition. It is also not always wise to implement: situations exist in which teachers are stretched too thin to be expected to find ways to improve student outcomes no matter the strength of incentives. However, PFP is only one approach to compensation reform.
The hard-to-staff schools model involves higher salaries for teachers who agree to work in high-needs schools or otherwise difficult educational environments. The San Francisco United School District provides up to $2,000 per year for educators who teach in high-needs schools — a list the district updates on an annual basis.
Relatedly, the hard-to-staff subjects model reflects the need to incentivize teachers to specialize in areas facing shortages of talent. For example, the Delaware Department of Education forgives college loans for students working towards teaching certifications in “shortage areas.” Students intending to teach middle school and high school math and/or science are given first preference for admission to the program.
To retain strong teachers and encourage them to take on additional responsibility, the career ladders approach pays more to teachers who do more for their schools. The New York City Department of Education implemented a teacher-leadership program in struggling schools that offered strong performers a host of new incentives, from a $7,500 raise to open up their classrooms for observation to a $12,500 raise for mentoring their peers and running schoolwide training sessions.
In addition, skills- and knowledge-based incentives are used to motivate teachers to achieve certain milestones related to professional development (e.g., special certifications). For example, Denver Public Schools increases a teacher’s salary by $759 for completing “Professional Development Units” which involve teachers learning/developing a new skill or capability, applying it to their classroom, and reflecting on its effectiveness.
The current salary model is ripe for improvement: seniority and education level are very weakly correlated with student outcomes. While there may not be a silver bullet for replacing the old model, there are plenty of options from which to choose. However, policymakers would be wise to take a page from the private sector: no business succeeds by paying their best and worst employees the same amount of money over an entire career.
Ned Shell is a joint degree graduate student at Harvard Kennedy School and Harvard Business School. He has a BA in International Relations from the University of... Read More
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New York City's anti-poverty initiative has won Harvard's 2011 Innovations in American Government Award.
To reduce the necessity of holding inmates for extended periods in segregation cells, the Alger Correctional Facility in Michigan started the "Incentives in Segregation" pilot project to reward positive behavior. Under the program, inmates work through six stages over several months, with each stage requiring certain tasks and granting certain privileges. The program boasts that it has reduced major incidents of misconduct in segregation by more than half and reduced days in segregation by 10 percent. States such as Ohio, California, Colorado, Maine, and New York are looking to replicate the program.
Maricopa, Arizona’s city council is piloting the use of iPads to reduce the paper waste that accompanies its meetings. Using the tablets and the free iLegislate app, officials are able to access agenda data on the go, take notes, and set follow-up tasks. Since its entry into the pilot, Maricopa has saved monies on paper, printing supplies, and personnel costs associated with assembling and distributing agenda packets.
The California Attorney General has launched a special task force to take on high-tech crimes in the state. Besides targeting identity theft (the state has over 1 million complaints per year), the new eCrime Unit will focus on Internet fraud, computer and electronic theft, intellectual property crimes, and child exploitation. The unit will rely on a team of experienced 20 attorneys and investigators to gather technical evidence across jurisdictions and initiate prosecutions.
Nevada’s Clark County School District hopes to staunch one of the highest dropout rates in the country by pairing at-risk students with mentors from the Las Vegas business community. Professionals must pass a background check and undergo training before being matched with a student. A similar program is already underway in Colorado.
With a nod towards speed dating, federal government groups are holding speed mentoring sessions several times a year to match mentors with federal employees looking for professional guidance. In 2011, the Federal Acquisitions Fellows Coalition, an interagency group of procurement workers, has sponsored 15-minute mentoring sessions where employees can gain access to leaders in their field. The Chief Human Capital Officers Council has held a similar event for emerging human resources leaders.
In Texas, the Austin School District has unveiled an immigrant-integration program that is helping parents learn English along with their children. The "Maestro en casa," or "Teacher at home," program provides parents with workbooks and a CD containing prerecorded lessons that teach conversational English. Lessons are also provided on health care, finance, workplace issues, citizenship, and the public education system. The goals are to ensure that students keep practicing their English at home and to help parents integrate into the school community. Around 1,000 parents are currently participating in the privately funded program.
Through the SaveUSA program, New York City is offering eligible low-income individuals a 50 percent match of their tax refund of up to $1,000 if they deposit the refund in a special account and maintain the initial deposit for approximately one year. The program, which began last year, is funded by a combination of federal and private grants, and has already helped many citizens open a bank account for the first time. The program has expanded to include Newark, New Jersey; San Antonio, Texas; and Tulsa, Oklahoma.
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Is another Duggar engaged? So far, there’s no official statement, but a series of posts from Amy Duggar, cousin to Jim Bob’s crew, and her boyfriend, Dillon King, seem to suggest that the two have taken the next step toward wedding bells. This follows the announcement of Josiah Duggar beginning his courtship.
Rumors of Amy’s engagement previously surfaced in January, and, according to IBTimes, she shot them down, saying she was ready, and that the pair had looked at rings, but that there was no official engagement yet.
In the past week, though, a series of posts seem to suggest the couple is moving forward — and today’s post especially seems to point to long-term plans.
The image is clearly celebrating their anniversary of five months dating, but this part has fans wondering if King is making plans.
Now, though, she has posted one that’s a lot more suggestive, and the way she’s captioned it really has fans speculating.
A few fans expressed concerns that perhaps the photo wasn’t about the couple being engaged, but about them ending their relationship. It seems the white line down the center looked, to many, like a declaration of a divide.
Amy’s post, however, strongly hinted at a positive relationship change. Is she engaged? Take a look at what she had to say and draw your own conclusions.
Hearts, smiley faces, and ‘lol’ don’t look much like a story of a breakup. Nor does putting their names together.
The whole message points much more to Amy Duggar being engaged to Dillon King than to any kind of breakup. Of course, the photo and message may just suggest that they should’ve always known they’d end up together — not that they’ve made any great leaps in the past few days.
People are asking questions on both Amy and Dillon’s Instagram photos, but so far the happy couple isn’t answering.
Christian Post reported last month that the Duggar cousin had expressed interest in her own reality show — a spin-off from 19 Kids and Counting.
A lot of fans find the slightly less conservative branch of the family intriguing, and their lifestyle is, of course, closer to that of many viewers.
So, is Amy Duggar engaged, or just enjoying her relationship? Only time (and the Duggars) will tell.
Dottie’s story in My 600-lb Life has always been one of the most emotionally jarring tales ever featured in the hit reality TV show. With a son suffering from cerebral palsy, a tendency to go overboard with taking care of her children, and a notable degree of stubbornness, it initially appeared that Dottie’s weight loss journey would be ridden with difficulties. As shown in the recently aired Where Are They Now episode, Dottie’s recovery from her morbid obesity indeed proved to be a steep uphill climb.
Dottie’s weight loss problems started way back in her childhood, as she developed intense abandonment issues after being neglected by her mother. When her first son, Daniel, was born and diagnosed with cerebral palsy, she continued to neglect herself, ultimately leading to her gaining so much weight that she weighed north of 600 pounds, according to a TV Ruckus report. While she continued to get support from her current husband, Chris, and her second son, Landon, Dottie still proved to be quite unstable, at least emotionally.
One thing that has stuck with viewers and avid fans of the acclaimed TLC series was just how stubborn and uncooperative Dottie was during her initial episode. To the dismay of most viewers and avid fans of the hit reality TV show, Dottie insisted on disregarding Dr. Now’s diet plan, insisting on one that she made for herself. Unsurprisingly, her self-made diet program proved ineffective, forcing Dr. Now to confine her to the hospital in order to limit her food intake, according to a TV Ruckus report. Daniel’s subsequent hospitalization, however, forced Dottie to devote all her time to her son once more.
In the recent My 600-lb Life: Where Are They Now episode, it was revealed that not long after she was first featured on the hit reality TV show, Daniel passed away. Dottie’s son, who had battled severe cerebral palsy for years, finally succumbed to his condition just months after her first featured episode aired. Being a dedicated mother, Daniel’s loss proved to be a massive roadblock for Dottie, who became at risk of regressing back to her unhealthy eating habits once more. In a rare interview with the Oxford Eagle last year, Dottie described the loss of her son as something that she finds too painful to even talk about.
Due to the tragic loss of Daniel, many fans and viewers of My 600-lb Life initially speculated that the dedicated mother might not go back for her Where Are They Now follow-up episode this 2017 anymore. As proven by the recently aired episode, however, Dottie proved to be resilient and dedicated enough to pursue her recovery despite the loss of one of the people she loved the most.
Needless to say, many viewers and avid fans of the hit reality TV show aired their admiration and respect to the recovering mother, stating that it must have taken much courage to come back to the show and open up about one of the most difficult points in her life. In online forums such as Reddit, numerous fans of the show stated that the recently aired episode was quite difficult to watch, with others stating that they shed tears as they watched what Dottie had to deal with over the past year.
While numerous fans of the show were rather annoyed at the way Dottie handled her situation when she was first featured on the show, viewers had nothing but praise for her in the recently aired Where Are They Now episode. After all, for a mother who lives for her children, the loss of a child is arguably the most devastating incident that can happen. Despite this, however, Dottie has still hung on, and while her progress might not be as drastic as other subjects that were featured on the hit reality TV show, the heart that she displayed as she returned for her follow-up episode is enough to gain the acclaim of the My 600-lb Life community.