A beautifully lit Christmas tree is one of the joys of the holiday season. But burned out bulbs and tangled wires can take the fun out of tree trimming. Graduate students at the University of Hertfordshire, in the United Kingdom may have found a way around this problem ? they’ve designed a genetically engineered Douglas spruce that grows its own “lights.” Says Katy Presland, one of the researchers, “We’re talking about a green luminescent Christmas tree that glows in the dark and produces a noticeable light during the day.” [1]

The tree requires two genes in order to produce light: one for the enzyme luciferase, which is found in fireflies, and one for a substance called green fluorescent protein, found in jellyfish. Both genes are placed in harmless bacteria, and these in turn are introduced into the tree seedlings. Light production also involves a compound called luciferin, which can be mixed into a special fertilizer provided with the tree.

Luciferase is the catalyst in a chemical reaction involving luciferin and oxygen. As with all enzymes, the luciferase speeds up the reaction without itself being changed. In the reaction, luciferin is oxidized-that is, it loses an electron ? and the molecules shift to a higher energy state. As the excited molecules return to their lower, more stable ground state, they release energy in the form of light. The light produced in this reaction in turn activates the GFP molecules, causing them to emit a green light that gives the tree its glow. [2] Scientists have also identified red and blue fluorescent proteins, raising the possibility of a tree with multicolored lights.

So far, the tree exists only on paper, but the technology has been proven to work; researchers have already used GPF to produce luminescent mice, potatoes, and silk. According to Presland, cost is the main obstacle to producing glowing trees. At least initially, a tree would run about $350 U.S. dollars ? more than most people would likely want to spend. But who knows… if the idea catches on, the lyric “you could even say it glows” will refer to more than Rudolph’s nose.

Recent requirements concerning the needs of special education students serve this concept well. Teachers must now make untimed tests available to large numbers of students. Since we already reserve Tuesday afternoon for untimed tests for all students, this particular need of special education students is well met. We prefer the concept that special education students are not singled out for this accommodation but are treated in the same manner as students without learning disabilities.

We have observed the development of a student backlash, in times of stress, against the “advantages” afforded special education students. This backlash will not occur if all students are treated in the same manner. We also prefer this in concept, because we believe that learning disabilities are not an on-off condition but rather a sliding scale on a continuum. Students whose “disabilities” are not severe enough to be positively diagnosed will still be well served by this approach.

We face the difficult problem of attempting to assess individuals while most of the work and assignments are collaborative. We have a strong preference for collaborative work, as described earlier, yet we do need to arrive at meaningful individual grades. How can we tie our students’ grades to their individual levels of understanding and functioning when most of the work is the result of group effort? One means would be to weigh so heavily the test scores that tests would be frightening experiences indeed. However, we believe that scholarly work is best done in a low pressure atmosphere, and that fear is a poor source of motivation in education, perhaps only as a last resort. Thus we seek to reduce pressure from testing while maintaining our accountability for measuring individual student understanding. The most stressful situation of all would be one in which the student has not developed the skills needed to be successful in the course, thus we have struggled seriously with the problem of maintaining accountability within a relaxed atmosphere.

We reduce stress of testing by heavily weighing other types of assignments, giving many re-tests, and establishing a forgiving system of late assignments (L-assignments turned in after the papers are returned to any class) so that you can simply concentrate on learning the material. We have developed the 150% rule (which restricts the grade on all assignments to no greater than 150% of the grade on the test covering that material) in an attempt to insure that students understand the main concepts within this relaxed classroom atmosphere. We have developed the 100% rule (which restricts L grades to 100% of the test grade on the same material) in order to get students credit for work done very late, but only to the extent that students can demonstrate an understanding of the subject matter. These rules would be severe indeed if students were not free to take re-tests, so we have recently instituted a policy that students may take or retake any and all major tests and most quizzes of the quarter on any Tuesday afternoon after school. We believe that students have as much opportunity as they need to demonstrate their grasp of the subject matter. We also believe that students can do poorly on a few assignments and still obtain a very high grade.

Stress reduction may also be accomplished by informing the student in great detail of the teacher’s expectations. Early in the course, we give the students very detailed evaluation sheets which accompany major projects. As the year progresses, these papers become less detailed.