In this study, the researchers compared various locations to see the relationship between sea otters, invertebrate herbivores, and macroalgae populations.  The idea was that in areas with sea otters, there wouldn’t be many herbivores, and thus an abundance of plants.  In areas without sea otters, the population of herbivores would be higher, resulting in fewer plants.  They selected 153 random sites in the Aleutian Islands and southeast Alaska.  For the most part, these sites followed the predicted paradigm, with one exception being Torch Bay.  This was because there were disturbances in the sea urchin population, causing the kelp abundance to vary significantly.  When sea otters spread into previously unoccupied locations, sea urchin population plummeted by as much as 100%.  Due to this, increases in kelp populations were abrupt and highly significant.  This study demonstrated that sea otter predation has a predictable and broadly generalizable influence over the structure of Alaskan kelp forests.

Source:

Estes, J. A., & Duggins, D. O. (1995).  Sea Otters and Kelp Forests in Alaska: Generality and Variation in a Community Ecological Paradigm.  Ecological Monographs, 65, 75-100.

Singh, Shane P. 2015. “Compulsory Voting and the Turnout Decision Calculus.” Political Studies 63(3): 548–68.

In order to determine how compulsory systems of voting affect the demographics of those who do end up going to polls, the author analyzes comparative data from various countries, as well as comparative data from Swiss cantons. He first lists the countries and cantons, and whether or not they have either voluntary voting, “weak” compulsory voting, or “strong” compulsory voting. (Varying levels of penalties for failing to vote) He then compares the differences in socioeconomic distribution of those who voted in the varying systems.

The author found that in countries where voting is mandatory, socioeconomic groups that are usually bad at turning out in countries with voluntary voting end up voting at similar rates to groups that usually turn out consistently.

Petrol, E., Gloor, G., Vanner, S., Weese, S., Carter, D., Daigenault, M., . . . Allen-Varcoe, E. (2013). Stool substitute transplant therapy for the eradication of Clostridium difficile infection: ‘RePOOPulating’ the gut. Micro biome. doi:10.3410/f.717977847.793470906

In this study, stool was obtained from a healthy, 41-year old woman and infused into the intestines of 2 patients who have a history of recurrent CDI.  The stool was cultured and purified.  Researchers isolated 33 strains of species sensitive to microbials (agents that slow/stop the growth of microorganisms) and infused for the final stool substitution.  Prior to depositing this mixture into the intestines, the patients were kept off of antibiotics for 2 days.  During the procedure, the mixture was deposited into the patients’ colons.  Afterwards, the patients were released an hour after the procedure and instructed to have a fiber-rich diet and take probiotics.  Testing for these samples included gDNA (genomic DNA) extraction and V6 rRNA amplification. gDNA was extracted by using a method called bead beating, in which a grinder was used “crack open” cells and then the samples were purified.  Polymerase chain reaction was used to amplify V6 rRNA, which is a section of the ribosomal RNA that demonstrates great biodiversity for bacteria, microorganisms, etc.  The samples were the sequenced to gain a fundamental understanding of the gene/genome for C. difficile.

The results were that the 2 patients went reverted to a regular bowel pattern 2 to 3 days after treatment.  6 months after the treatment, the patients remained symptom-free of CDI.  This study could have been improved on or furthered by following up with the patients after the 6 month mark, because the long-term effects of biotherapy/stool transplantation cannot be determined based off the results after 6 months.

This research article talks about how to help the sea otters that are listed on the Endangered Species list in the islands off the coast of Alaska by using their ecosystems. Researchers planned on developing a recovery criterion for the sea otters and its ecosystem on the basis of ecological effectiveness.  The reason they did this was because sea otters help preserve sea kelp, which gives off lots of carbon. Sea otters do this by eating sea urchins, which cause kelp forest to deplete. In order to confirm that keeping sea otters within these areas would be efficient for the ecosystem scientist took measurements of kelp and sea urchins in random spots within the coast of the islands. They tested areas that had sea otters at their capacity and other areas that lacked sea otters. The areas that had sea otters showed a low sea urchin biomass and a high kelp population, while the areas with little to no sea otters where shown to have high urchin biomass and low kelp density. These results proved that the rocky reef ecosystem in Alaska’s islands is predictable depending on the presence or absence of sea otters. Researchers hence proved that sea otters helped their ecosystem as much as the ecosystem helped them and they were essential for each others survival, but too many otters would not bring homeostasis to the reef either.

Citation: ESTES, J. A., TINKER, M. T. and BODKIN, J. L. (2010), Using Ecological Function to Develop Recovery Criteria for Depleted Species: Sea Otters and Kelp Forests in the Aleutian Archipelago. Conservation Biology, 24: 852–860. doi:10.1111/j.1523-1739.2009.01428.x

A psychological study done on resilience in U.S. military veterans has the veterans take online surveys in two waves. The first wave cumulatively measured the overall lifetime effects of traumatic events while Wave 2 assessed current symptoms of disorders such as “PTSD, major depressive disorder, as well as anxiety” in the veterans to classify them into different profiles based on the psychological disorders.  The control group with a “low lifetime trauma exposure” was compared with two groups: “resilient group with high lifetime trauma and low current distress, and a distressed group with both high trauma exposure and current distress symptoms.” The findings of the study confirmed that majority of veterans with trauma did in fact have high resilience.

Source:

PARKER-POPE, TARA. “How to Build Resilience in Midlife.” The New York Times, The New York Times, 25 July 2017, www.nytimes.com/2017/07/25/well/mind/how-to-boost-resilience-in-midlife.html?rref=collection%2Ftimestopic%2FPsychology and Psychologists&action=click&contentCollection=health®ion=stream&module=stream_unit&version=latest&contentPlacement=9&pgtype=collection. Accessed 29 Aug. 2017.

Ridaura, V. K., et al. “Gut Microbiota from Twins Discordant for Obesity Modulate Metabolism in Mice.” Science, vol. 341, no. 6150, May 2013, pp. 1241214–1241214., doi:10.1126/science.1241214. <http://science.sciencemag.org/content/341/6150/1241214.full>

The article entitled, “Gut Microbiota from Twins Discordant for Obesity Modulate Metabolism in Mice,” published in the journal Science, is about the effect of gut bacteria on obesity. Researchers found sets of human twins in which one of the twins was thin and the other obese. The scientists then transferred the twins’ fecal bacteria to several mice that were also genetically identical. (Genetically identical mice—as well as humans—were important because genetic and environmental factors had to be controlled.) Also, the mice were raised in a sterile environment so they lacked any bacteria of their own. Approximately five weeks after the mice were given gut bacteria from the human twins, those that were given bacteria from obese twins had 15 to 17 percent more fat than those that were given bacteria from thin twins.

The next stage of the experiment involved placing mice with bacteria from thin twins in a cage with those that had gut bacteria from obese human twins. Mice ate each other’s droppings, so the researchers were curious to see if the gut bacteria would mix. To their surprise, the mice that initially had bacteria from the obese twins started losing weight as they consumed feces of mice that initially had bacteria from the thin twins.

Lastly, the researchers decided to vary the types of diets that the mice had. Fat mice that ate foods high in fat retained the gut bacteria they acquired from the obese twins and remained fat. Only fat mice that ate food high in vegetables and fruits had an increase in gut bacteria from the lean human twins.  

The researchers in the article “Development of a Method for the Determination of Human Skin Moisture Using a Portable Near-Infrared System” sought to create a more accurate and portable method of determining skin moisture. They conducted research to determine what moisture-detecting systems were already in place and created their portable near-infrared system (NIR) based on a more expensive model.

To test their NIR system, the researchers began with a group of 6 hairless mouse dorsal skin from two different male mice. The skins were first soaked in water for one hour so they could contain the maximum amount of water possible. The device was used on the skins every hour during a 90-hour period as they dried.

Afterwards, the device’s effectiveness was tested on 10 human participants’ arm skin. All of the experiments were performed in the same environmental conditions within a lab. Throughout the entire experiment, the conventional scanning-type NIR spectrometer—the more expensive NIR system that the researchers used as a baseline for their research—was used to compare results.

The researchers found that their portable NIR system was more accurate to use than the methodologies used to measure skin moisture before. This was due to the fact that their system was faster and was less sensitive to external environmental conditions such as temperature and humidity.

Woo, Young-Ah Ahn, Jhii-Weon, Chun, In-Koo, and Kim, Hyo-Jin. (2001). Development of a Method for the Determination of Human Skin Moisture Using a Portable Near-Infrared System. Analytical Chemistry, 73, 4964-4971.

In order to assess the relationship between sea otter population and the abundance of kelp forests, researchers conducted surveys in Alaska, comparing the densities of kelp forests in areas with a large sea otter population and areas with a small sea otter population. At several different sites lining the Alaskan coast, the density of kelp forests were measured by a scuba diver counting the amounts of kelp in specific sectioned off areas, with varying sea otter populations that were calculated in previous experiments.

The experiment concluded with results that showed that the decrease in kelp forests coincided with the decrease in sea otter population. Kelp density varied strikingly between areas with an abundance of sea otters in comparison to areas with a lower abundance, suggesting that the presence of sea otters protected the surrounding kelp forests and encouraged their propagation.

Estes, J., & Duggins, D. (1995). Sea Otters and Kelp Forests in Alaska: Generality and Variation in a Community Ecological Paradigm. Ecological Monographs, 65(1), 75-100. doi:10.2307/2937159

Kerdijk, W., Cohen-Schotanus, J., Mulder, B. F., Muntinghe, F. H., & Tio, R. A. (2015). Cumulative versus end-of-course assessment: effects on self-study time and test performance. Medical Education, 49(7), 709-716.

In the article, researchers conducted an experiment to see if there was a difference between self-study habits when taking cumulative and end-of-course exams. To do this, they randomly assigned 78 students to one of the two testing conditions and each week every participant had to fill out a survey to document how many hours they studied on their own. The participants in the cumulative testing group had to take three tests throughout the semester whereas the participants in the end-of-course group only had to take one test during the final week. Both groups were given the same set of questions in the final exam, and the results were then compared. In addition to comparing the final test scores, the researchers calculated the GPA of each student in prior courses to assure that there was no significant difference in academic performance between the groups to make sure the results were not biased.

They found that there was no significant difference in performance in the course, however, students in the cumulative testing group studied more and did better on questions regarding material covered during the last two weeks of class.