Investigating the Effects of Temperature and Carbon Dioxide Levels on Nannochloropsis oceanica Using a Hemocytometer Counting Method
Climate changes that include ocean acidification and global warming are serious problems in the ecosystem, affecting marine phytoplankton, including Nannochloropsis oceanica. In the effort to further explore the impact of rising temperature and carbon dioxide (CO₂) concentrations on oceanic ecosystems, the phytoplankton Nannochloropsis oceanica was used as a model organism. This study explored the effect of temperature change and CO₂ concentration on the growth of Nannochloropsis oceanica, achieving 243 samples that were tested with three different temperatures (24 degrees Celsius (°C), 28°C, 32°C) and CO₂ concentrations (0 milliliter (ml)/min, 0.4 ml/min, 0.6 ml/min), utilizing a hemocytometer counting method. Results indicate that the CO₂ concentration has a significant effect on the population of Nannochloropsis oceanica. But the temperature doesn't affect a lot. The Nannochloropsis oceanica in the lowest temperature and highest concentration of CO₂ in its environment had the highest population growth, and in the highest temperature and lowest concentration of CO₂, it had the lowest population growth. Results show the serious negative effect of climate change on the cosystem and the importance of environmental protection. Population blooms due to excess CO₂ taking up ocean resources causing dangerous ecological imbalances.
Quantitative environmental DNA metabarcoding for the enumeration of Pacific salmon (Oncorhynchus spp.)
Understanding species abundance is critical to managing and conserving planetary biodiversity. Pacific salmon (Oncorhynchus spp.) are keystone species of cultural, economic, and ecological importance in Alaska and especially Southwest Alaska. Traditional methods of enumerating salmon such as weirs and visual surveys are often costly, time-intensive, and reliant on taxonomic expertise. Environmental DNA (eDNA), which identifies and quantifies species based on DNA they shed in their habitats, is a potential cost- and time- saving alternative. The relative ease of collecting eDNA samples also enables citizen scientist involvement, expanding research coverage. Currently, more research is required to define eDNA’s potential and limits. This project investigates whether quantitative eDNA metabarcoding can accurately quantify the abundances of six fish species: the five Pacific salmon species plus rainbow trout. Water samples were collected from eight creeks in the Wood River watershed of Southwest Alaska. eDNA metabarcoding and subsequent bioinformatics processing produced a read count for each species. These were compared to visual survey counts, taken to be the true counts for the purposes of this study. Data analyses showed a positive, linear relationship between visual survey count and eDNA count for sockeye salmon. The regressions were significant for both the early (p = 0.089) and late (p = 0.030) sampling dates when 𝛼 = 0.10. eDNA detections of non-sockeye species generally corresponded to visual survey observations of species presence or absence. Overall, the results of this study support eDNA’s potential to be an alternative or supplement to standard methods for the enumeration of fish species.
Vitas: Digital Therapy Based on a Combination of Binaural Beats and Autonomous Sensory Meridian Response (ASMR) to Reduce Stress in Gen Z Students
Vitas is a combination of binaural beats (BB) with background white noise (ASMR) as accompanying music without reducing the quality of brain stimulation and is able to stimulate the left and right brain while synchronizing brain waves so that it can be used as a media for coping with stress for Gen Z students. To find out the effect Vitas in reducing stress levels, research was conducted on high school students belonging to Gen Z. This research aims to measure the stress index of students belonging to Gen Z, then find the effect of the combination of binaural beats (BB) and ASMR on students'stress levels, and finding the best audio combination to reduce stress levels as a coping mechanism. This research uses a quantitative approach with a quasi-experimental design using a one group pre-test-post-test design scheme. The sample in this study consisted of 105 students who were divided into seven treatment groups to listen to a combination of BB and ASMR with different bandwidths. Stress levels were measured using the DASS 42 stress section questionnaire which has been tested for reliability and validity. The results of the student stress index were 16.26 in the mild stress category. There was a significant difference between the negative group, the alpha + ASMR group and the positive group with a T-Paired test result of less than 0.05. Based on the results of the Post Hoc LSD test, it was found that the combination of binaural beats alpha (12hz) + ASMR was the best combination for reducing stress in students.These findings were developed into a digital therapy application product called "Vitas" as an alternative media for coping with stress for Gen Z.
格子點的可見性研究
本文的主要結果有兩部分，第一部分，對於固定的𝑏 ∈ 𝑁以原點 O為觀測點，𝑓(𝑥) = 𝑎𝑥𝑏, 𝑎 ∈ 𝑄為觀測視線，觀測目標為格子點陣列𝑉(𝑚) = {(𝑖, 𝑗)|𝑖, 𝑗 ∈ 𝑁, 1 ≤ 𝑖 ≤ 𝑚, 1 ≤ 𝑗 ≤ 𝑚 }，研究其中可見點的數量與機率。我們發現可見點的數量與歐拉函數及默比烏斯函數有關，可見點的機率也與黎曼𝑧𝑒𝑡𝑎函數具有關聯性。第二部分，對於固定的𝑏 ∈ 𝑁，我們在 𝑥軸與𝑦 軸上布置觀測點，以布置的觀測點為新原點，𝑓(𝑥) = 𝑎𝑥𝑏, 𝑎 ∈ 𝑄為觀測視線，研究將目標點集𝑉(𝑚 × 𝑛) = {(𝑖, 𝑗)|𝑖, 𝑗 ∈ 𝑁, 1 ≤ 𝑖 ≤ 𝑚}完整觀測的布點方法與數量。得到重要成果如下，設正整數𝑚 ≥ 6且𝑇 ⊂ {1, … , 𝑚 + 1}為一個 𝐹(𝑚) −覆蓋，𝑟為大於𝑚的最小質數，對於目標點集𝑉(𝑚 × 𝑛)，建構觀測點集 𝑆2 = {(0, 0), (0, 𝑟)}∪{(𝑡, 0) | 𝑡 ∈ 𝑇}，則 𝑉(𝑚 × 𝑛)為𝑆2 −可見。並進一步研究將目標點集改為𝑉(𝑛 × 𝑚) = {(𝑖, 𝑗)|𝑖, 𝑗 ∈ 𝑁, 1 ≤ 𝑗 ≤ 𝑚}，發現其所需要的觀測點數可顯著減少。