Summer Science Research at Bryn Mawr

'2004' Archive

The Synthesis of Hemiaminals as Potential Protease Inhibitors

Posted May 28, 2010

Hemiaminals are structures containing a carbon attached to a hydroxyl group and an amine. They have the same oxidation state as aldehydes, which have been proved to effectively inhibit proteases. In addition, they have the potential for extended binding interactions in the enzyme active site, leading to stronger and more specific inhibitors. Thus, hemiaminals can potentially inhibit serine proteases, which are enzymes that catalyze the hydrolysis of peptide bonds by a nucleophilic attack on the targeted bond by a serine.

The Effects of Long Initial Links on Persistence Preference

Posted May 28, 2010

The current research is aimed at examining persistent preference based upon terminal-link entry in choice situations. Twelve pigeons, six naive and six with a history of exposure to concurrent-chains schedules, will be presented with concurrent-chains schedules with relatively long initial links. Similar research has been conducted with relatively short initial links (fixed interval 3s), but the generality of the findings is being explored by lengthening the initial links to fixed intervals of 15s, 30s, and 60s, depending on the condition.

Previous research involved changing terminal links from VR 60/VR 60 (equal alternatives condition) and VR 60/ VR 30 or VR60/ VR 90 (unequal alternatives condition), and then returning to the equal alternative condition to examine persistent preference. The use of short initial links in previous research resulted in preferences based almost exclusively on the terminal link response requirements; however, the current research is designed to investigate whether lengthening the initial links (terminal links are unchanged from previous research) will influence persistent preference.

The Effects of the Septum on the GABA Gate

Posted May 28, 2010

This summer’s research project will focus on how the septum and the amygdala work. The amygdala and septum are structures in the brain that are involved with anxiety. The amygdala helps stimulate symptoms of anxiety (anxiogenic) and the septum helps inhibit symptoms of anxiety (anxiolytic). Some chemicals that help regulate anxiety are Benzodiazepines (BZD) and GABA. BZDs are anxiolytics that are used to help relieve symptoms of anxiety. When BZDs bind to their receptors they help facilitate the binding of GABA to their receptors. GABA is an inhibitory neurotransmitter found in the amygdala. Previous literature states that the activation of the amygdala causes the stimulation of the septum. Once the septum is activated it will cause the amygdala to become inactive. The question is, do the septum and GABA neurotransmitter work together to inhibit the amygdala? It is hypothesized that the septum controls GABA and inhibits the amygdala via GABA. So both GABA and the septum are needed to help inactivate the amygdala. To test this hypothesis a GABA antagonist, Picrotoxin, will be injected into a rat. This will prevent GABA from working and so even though the septum will be stimulated the actions of the amygdala will still be active. Without GABA the septum has no affect on the amygdala.

Children’s Understanding of Wicked Desires

Posted May 28, 2010

This summer I will begin doing research for my own undergraduate thesis, which will involve the study of the development of children’s Theory of Mind. It will be an extension of past research done by Professor Kim Cassidy and Katrina Magdol ’04. Theory of Mind is children’s understanding of persons’ mental states, such as desires and beliefs. Past research has shown that although young children are told that someone has a wicked desire, once the desire is fulfilled they think the person who had the wicked desire will be sad. For example when told that Jimmy does not like Bobby and wants to hit him, after Jimmy does hit Bobby, a child will say that Jimmy is now sad even though it is what Jimmy wanted and intended to do. Past researchers have said that this is because young children are egocentric in their thinking and are unable to comprehend that a child would have a wicked desire. Young children do not appear to be able to think of others as subjective beings. Past researchers claim that young children do not attribute thoughts and emotions different from their own to others, and would not understand that a child could be happy that his or her desire has been fulfilled because the desire was bad.

The Impact of Science Education on Women’s Scientific Endeavors

Posted May 28, 2010

A sample of Bryn Mawr alumnae were recently asked to complete a survey to explore their perceptions and attitudes towards science education as well as their views of women’s involvement in the field of science. The purpose of this study is to examine and explore the various factors that govern women’s decisions to pursue their interests in science within an educational setting. The greater goal of the “Bryn Mawr Women, Education, and Science Study” is to initially identify the aspects that impact women’s interest and aptitude in the sciences and then to use these findings to better address and encourage the greater participation of women within the sciences. More specifically, the study endeavors to illuminate what sorts of programs and teaching methods are most effective at supporting women’s interest and involvement in science at Bryn Mawr College . The results of this survey may shed some light on the underlying dynamics that influence the involvement, or lack thereof, of women in the scientific realm. By understanding women’s relationships with science both outside and within an educational setting, a greater understanding of more effective teaching methods and increased involvement can be achieved.

Comprehension of Enactive Representations in Young Children

Posted May 28, 2010

This study asks the questions, “What do children understand about the communicative function of action? Can they recognize an action as a representation of an object, and can they use that enactive representation communicatively to respond to a request?” Our aim is fourfold. First, to study comprehension of enactive representations as a function of age, we ask whether young children can correctly interpret empty-handed actions as representing an object and if so, at what age? Second, we evaluate potential developmental differences between comprehension of BPO (body part as object) vs. IO (imagined object) gestures. Third, we assess whether it is possible to train those children who do not already comprehend one or the other gesture type. Finally, we would like to see which is the more powerful predictor of gestural comprehension ability: age or language ability (as measured by vocabulary size). Our questions will be answered through testing 24 or 34 month old children. Subjects will be asked to select a toy from a small group based on a gesture preformed by the experimenter. It is expected that the younger children will not be able to retrieve the desired toy when shown IO gestures; however we predict they will be able to correctly complete the task when shown BPO gestures.

Gender Stereotypes and Name Phonology

Posted May 28, 2010

A good deal of previous research has explored the development of children’s knowledge of gender stereotypes. Leinbach (1997) established that, by the age of four, children know a good deal about gender and have set ideas in their minds about what is permitted for each sex. In our society, forenames are used as indicators of the sex of the individual. Recent research has shown that forenames contain phonological cues to their gender; for example, female names are more likely than male names to end in an ‘a’, and if there are three syllables in the name, the stress is typically put on the second syllable for female names, as in the case of ‘Christopher’ and ‘Christina.’ It has been found that English-speaking adults and children use name phonology to categorize the gender of names (Cassidy, Kelly, & Sharoni, 1999). Gender has an effect on how people in society act and react to each other. Given that children know stereotypes and phonological cues to gender, I am interested in studying the development of such stereotypes, and their relation to name phonology.

Revisiting the Operant-Respondent Distinction

Posted May 28, 2010

The distinction between respondent (Pavlovian) and operant discrimination has been demonstrated spatially using a multiple schedule. Marcucella (1981) suggested that respondent and operant conditioning can be separated temporally using a single key procedure, which allows for the analysis of the dynamics of superimposed respondent-operant behavior. The present research is modeled after Marcucella’s but with the addition of a yoked procedure (a primary pigeon’s behavior produces consequences for both pigeons, and the second pigeon’s behavior is documented but does not affect the procedure). Three distinct multiple schedules with 4 components were used: the first multiple schedule began with a 6 second extinction period, followed by a variable interval (VI) one minute schedule in place for 54 seconds, another 6 second extinction period, and another VI one minute schedule for 54 seconds. In phase two, the stimuli present during the short periods were changed from “white” to “red” or “x”. In phase three, one VI period was changed to extinction. The second condition was identical to the first except a random interval one minute schedule was used in place of the variable interval one minute schedule; the third condition was the same as the second except a blackout period followed reinforcement in the random interval one minute schedule. The results from the first two conditions did not support Marcucella’s finding that respondent and operant conditioning can be temporally separated using a single key procedure. The third condition directly shows a respondent-operant distinction and suggests that adding a blackout period makes respondent discrimination more likely to occur after operant behavior with this type of multiple schedule.

Studying the Dipole-Dipole Interaction of Rydberg Atoms in a Magneto-Optical Trap

Posted May 28, 2010

A magneto-optical trap (MOT) uses a combination of magnetic fields and laser beams to hold a gas of atoms in a frozen configuration. The MOT at Bryn Mawr uses Rubidium atoms for this purpose. Once the atoms are isolated they can be excited to Rydberg states by focusing an additional laser beam into the trap. A Rydberg atom, because of its weakly-bound valence electron, behaves like a dipole and is highly sensitive to external electric fields. The exaggerated properties of Rydberg atoms allow them to interact strongly by means of the dipole-dipole interaction over the long distances separating them in the trap. This is similar to the interaction between the atoms of a solid where the inter-atomic spacing is a thousand times smaller than that of a frozen gas. Trapping atoms in a MOT therefore helps us observe microscopic atomic interactions at a significantly magnified scale. My research project involves exploring how the dipole-dipole interaction depends upon the density of the sample of Rydberg atoms as well as its dimensionality.

Construction of a Magneto-Optical Trap for the Trapping and Cooling of Rubidium Atoms

Posted May 28, 2010

A magneto-optical trap is used to isolate and cool clouds of atoms. Lasers are used to bombard the atoms with photons thereby exchanging momentum with the atoms and damping their motion in the direction of the laser. By using lasers in multiple directions of motion, the photon-atom collisions cause the atoms to lose kinetic energy, independent of their direction of motion, until they are nearly motionless. In this super-cooled state the temperature can be as low as 1 m K. Magnetic fields are used to direct and congregate the atoms into a certain region of space within a vacuum and trap them for an extended period of time. This summer I am constructing one such trap, however, instead of capturing clouds of atoms my goal is to have the trap be precise enough to capture and cool individual atoms. The key to achieving this will be to use tightly focused laser light to capture and observe one atom at a time. Beyond construction of the trap, further research will possibly involve observation of the properties of the individual atoms in their super-cooled states as well as there interactions with each other.

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