全國中小學科展

2017年

How to spill your coffee

We all do it – walk along with a cup in hand, and carelessly spill it. While it’s usually more annoying than anything else, it happens to affect almost all of us, and little is done to minimise the likelihood of it occurring. So my aim was to explain the physics behind why we spill drinks when we walk, and to investigate how we can minimise the likelihood of this occurring. I broke this investigation into two distinct parts, explaining the system of the cup, and explaining the effect of walking. From initial observations, it was clear that the cup was a resonating system. Like any resonating system, the cup has a natural frequency. When the cup is oscillated – moved back and forth – at near this frequency, the size of the liquid oscillations is very large. This is because the acceleration is in phase with the motion of the liquid, so in each cycle maximum energy is input into the system. In my investigation I experimentally measured this natural frequency, and created a mathematical model to explain this frequency. It was also found that as the size of liquid oscillations in the cup increases, so does distortion of the fluid surface, possibly enabling spilling. To systematically analyse the effect of walking, I had subjects walk on a treadmill, so walking surface and speed were controlled. However, I also needed an accurate way of measuring the motion of a carried cup. Firstly, I tried to use video analysis; however I found this far too imprecise for measuring small changes in velocity of a cup. In the end I used a smartphone to record the acceleration of a carried cup, as acceleration is what causes the movement of liquid in a cup. This allowed surprisingly accurate measurements to be made, and allowed both the size and frequency of the acceleration to be recorded. In order to relate the system of the cup and the oscillation provided whilst walking I conducted a qualitative experiment into the effect of stride frequency on the likelihood of spilling. When stride frequency was very close to the natural frequency of the cup, spilling occurred almost instantly, while it did not occur if stride frequency was much higher or lower. In the end, my research showed that to minimise the likelihood of spilling your drink walk slowly, use a narrow cup, focus on walking smoothly, and fill the cup well below the rim. Despite this, some people happen to be much smoother cup carriers than others, likely due to their individual biomechanics. And, if you really don’t want to spill your drink, you can always use a lid.

The Locus of Mid-Tangent Points of Planar Curves

In this project, we defined a mid-tangent point with respect to a fixed point X and a tangent at a point Y on a planar curve C as a point on the tangent that is equidistant from X and Y. We studied the locus of mid-tangent points of conic sections. We found that the locus of mid-tangent points of most conic sections are non-linear curves. However, we observed and proved by using Euclidean geometry that the locus of mid-tangent points of circles are straight lines. The mapping defined by mid-tangent points was studied further. The similarity between a mid-tangent mapping and a stereographic projection was displayed as a one – to – one correspondence function. We also extended the concept of mid-tangent points to three dimensional space and found that the similarity with the stereographic projection was retained in higher dimensions. Finally, we studied the locus of mid-tangent points of a sphere to create a mapping of the sphere to a plane.

英文篇章難易度自動分級之研究

以製作適合高中生的英文篇章難易度自動分級為初衷,本研究採高中英文課文為語料,針對「如何分級」,意即從文章萃取哪些特徵、利用何工具或語料協助萃取特徵、以何工具分級等因素,進行研究與實驗,並建立一套新方法。首先進行前處理,再嘗試以單字、句型的數量或比例、句長、音節長、整合以上分析等各式特徵,支持向量機(Support Vector Machines)、隨機森林分類器(Random Forest Classifier)、決策樹分類器(Decision Tree Classifier)、卷積神經網路句分類器(Convolutional Neural Networks for Sentence Classification)等工具,進行將篇章分為高中一、二、三年級等三個難易度等級的測試,建立自動分級模型。最後製作成可供大眾使用的自動分級網頁。各項測試之中,最佳分類效能為整合各項特徵時得到的分類正確率65.04%,經模擬得知,此效能較過去研究,已有所提升。

多方塊的塗色問題

在本篇研究報告中,主要討論一個關於多方塊的問題:給定一個多方塊,試找出n的最小值使得在無限大的棋盤上,可以塗上n種顏色並且使多方塊沿格線無論如何放置,都不會蓋到重複的顏色。一開始先以V形三方塊的情況開始討論,之後將單方塊至五方塊的所有情況都有系統地討論完畢。 為了給出顏色數的估計,考慮同時適用於所有k方塊的情況。也就是說,要找到一個塗上n種顏色的無限棋盤使得無論任一個被選定的多方塊怎麼被放置在棋盤上,都不會覆蓋到相同顏色的格子。本篇研究成功地給出了此問題的精確解。 除了上面一種估計之外,本篇研究也考慮了矩形多方塊的顏色數,並試圖以之給出所有多方塊所需的顏色數之上下界。最後我得到k方塊所需的顏色數至多為8(k+1)2/25.

Investigating the Effect of Coloured Light on the Behaviour and Learning of Lymnae stagnalis

Lymnae stagnalis (pond snail) is emerging as a preferable invertebrate model in understanding neurological mechanisms because of its simple nervous system. A three-cell network mediates behaviours such as aerial respiration and research has shown that small, subtle changes occurring across the network might result in a disruption of natural behaviour (Lukowiak et al. 1995). It is also known that Lymnae features a more developed eye than other molluscs and studies have shown that various wavelengths of light can activate photoreceptors producing distinct electrophysiological responses (Sakakibara et al. 2004). However, no studies have looked beyond the electrophysiological response. The purpose of this project was to determine if coloured light would firstly, elicit a behavioural response as observed in its movement and secondly, affect learning and memory through the operant conditioning of its aerial respiration.

SeedBot: Low-Cost Seeding Robot for Agricultural Applications

This paper presents a semi-autonomous seeding robot which is based on both electrical and mechanical platforms that perform advance agriculture process. SeedBot composed of four components: drilling mechanism, body of robot, seed container and paving mechanism. Other than those components the sensor system and the control system are also discussed. The aim of this study is designing and building a low-cost robotic system to automate and optimize process during farming especially for personal usage. This study demonstrates that semi-autonomous farming has crucial advantages over conventional farming. In addition to that, SeedBot provides safer, requires less manpower and precise farming than usual methods that we have so far.

以蛋白質體學方法鑑定人類肝癌細胞經蕾莎瓦治療之預後的潛力生物標記 Identification of Potential Prognostic Biomarkers in Hepatocellular Carcinoma Cells Treated with Sorafenib

肝癌是死亡率極高的癌症。目前並無非侵入性方法判斷標靶藥物治療效果。蕾莎瓦(Sorafenib)是一種使用於肝癌晚期治療的標靶藥物,但有些病患在治療過程中會出現抗藥性,因此可預測蕾莎瓦治療效果的生物標記相當重要。 血液中的生物標記可及時追蹤疾病進展與預後之評估。本實驗利用質譜法鑑定分析在肝癌細胞(HuH7)中加入蕾莎瓦模擬治療後肝癌的分子機轉,並透過生物資訊軟體了解蛋白質在HuH7細胞中所扮演的角色。我們發現Galectin-3 和HMGB1可能參與腫瘤細胞的增生和遷移,以西方墨點法觀察其表現量,發現Galectin-3 和HMGB1在受到藥物處理後,表現量皆有下降的情形。 蕾莎瓦可抑制B-RAF激酶進而阻斷MAPK pathway。MAPK pathway又可分成ERKs、JNKs和p38/SAPKs三類。為確認Galectin-3之訊息傳遞路徑,將蕾莎瓦和ERK抑制劑處理細胞,發現Galectin-3的表現量隨著時間而下降,證實Galectin-3的表現會受到ERK路徑調控。 Galectin-3與 HMGB1是極具潛力的生物標記可應用於蕾莎瓦的治療,希望這些生物標記可以應用在臨床上。

A Novel Selection Process for the Conversion of Conventional Bacteria into Electrotrophs

The redox reactions of bacteria metabolism have been extrinsically studied. These mechanisms allow certain types of bacteria to be able to synthesize extremely valuable extracellular byproducts. Other types of bacteria are able to extract toxic metals from water by donating electrons directly to those aqueous metal ions, thus turning them into solid precipitates. However, the problem of these microorganisms is that their efficiency rates and production speeds are exceptionally low. This study focuses on the properties of electrotrophs, which are bacteria that can feed on pure electrons directly from an electrode (Rabaey et al 2010). Compared to normal organic-feeding bacteria, electrotrophs direct the majority of the electrons obtained to the production of metabolic byproducts (Nevin et al 2010). Therefore, when electrotrophs are employed in bioelectrochemical systems (BESs) their metabolic redox reaction efficiency rates are dramatically increased. This makes it possible to produce large quantities of valuable compounds such as hydrocarbons, plastics and medicine or efficiently remediating the environment (He et al 2016). Moreover, the usage of electricity as an energy source compared to conventional organic substrates is immensely cheaper (Rabaey et al 2010). However, not all bacteria are electrotrophs nor do all electrotrophs have favourable metabolic traits. Thus, there is a need for a novel procedure to turn conventional bacteria into electrotrophs which is a crucial step to making the BES an aggressive competitor in the sustainable energy industry.

The impact of climate variability on infectious disease

Diarrhoea is an infectious disease that claims many lives (particularly among infants) and is known among many other infectious diseases, to have a relationship with climate. This projects quantifies this relationship by comparing health insurance treatment claims for diarrhoea and anti-diarrheal drug sales data from the private health sector with temperature and rainfall data provided by the South African Weather Service. The data were then analysed and show that incidence is highly seasonal and varies among regions with different seasonal climates. The results show that climate variability can explain 73% of diarrhea incidence variation with rainfall explaining 8% and minimum temperature explain the other 65 %. Preliminary predictions of future monthly percentage increases in incidence were then made for a series of time ranges. This project demonstrates that with predicted climate data one can predict future variations of diarrhoea allowing the health sector to be adequately prepared.

Neolema ogloblini- An agent in the biological control of Tradescantia

Tradescantia (Tradescantia fluminensis) is the worst weed in New Zealand. By smothering and shading out seedlings, Tradescantia prevents forest regeneration. Current control methods are ineffective and simultaneously cause harm to native forest. In 2011 Neolema ogloblini, a Brazilian beetle was introduced into New Zealand as a biological control for Tradescantia. To be successful in New Zealand, a country with different environmental factors, the beetles’ ranges of preference (temperature and light intensity) had to be investigated. A gender specific trait also identified, to enable desired sex ratios within founding populations to be selected. [18] This would ensure that the beetles are not released in areas of physiological stress, and can be optimised to have the greatest impact on Tradscantia. To establish how the intensity of light affects the distribution and amount of Tradescantia eaten by N.ogloblini a choice chamber investigation was conducted. Different layers of shade cloth provided a range of light intensities 150-3450Lux (likely to be found under forest canopy where Tradescantia is problematic). Thirty beetles of a range of sizes and approximately same maturity were randomly distributed through the chambers. Each chamber contained a shoot of Tradescantia with 5 leaves. After a 24hour period the number of beetles in each chamber were counted and the amount of surface area of the leaves eaten measured. The effect of temperature on the amount of leaf surface area eaten was investigated by selecting 90 beetles of a range of sizes and withholding food for 24hours. Five beetles were placed in each of three containers containing two leaves. Each trial container was precooled/warmed to the test temperature before the beetles were added. Leaves of a similar size, shape, mass and maturity were used. All leaves were genetically identical and collected from the same location. Sets of three containers were held in the dark at the following temperatures for 24hours: 9°C, 15°C, 20°C, 25°C, 30°C and 35°C. The surface area of leaf eaten at each temperature (mm2) was calculated. Lastly, microscopic dissections were conducted, using 32 beetles ranging in size, to establish if length (measured from the top of the head to the base of the abdomen) could be used as a phenotypic marker to identify beetle gender. While only a very weak positive relationship between increasing light intensity and the number of beetles was found a significantly higher area of leaf was eaten at a light intensity of 3450Lux compared to 150Lux. The amount of leaf area eaten is significantly reduced at temperatures of 15˚C and below, and significantly increased at 35˚C. There is no significant difference in the amount of leaf area eaten when comparing temperatures between 20-30˚C. Females have on average a larger body length (median=4.92mm) than the males (median=4.215mm). Therefore, sites with warmer temperatures in dappled light conditions (3450Lux) should be prioritised for the release of N.ogloblini, as this is the location in New Zealand at which their use as a biological control will be optimised. Beetle length can be confidently used to select desired gender ratios.