本欄逢周四刊登，由教育評議 會邀請資深中小學老師、校長及大 學講師撰稿，旨在為學生提供多元 化的STEAM學習材料，引發學生 探求知識的興趣，將學習融入生 活，培養學生的世界觀、敏銳的觸 覺、積極學習的態度。 蚊叮後 為何紅腫痕癢？ 我們被蚊叮後會有紅腫痕癢的 感覺，不是因為被蚊的針刺傷， 而是我們的身體對蚊子吐出的唾液 過敏反應。我們的身體有凝血的機 制，只要血管受損時，血液就會 迅速轉為凝膠狀態，以減少失血。 因此蚊子要從我們身上開懷暢吸血 液，便要發展出一個獨特的口器 （mouthparts）。蚊子的口器是由「6 根針」組成，最外圍的2根針是用來 刺破及鋸開人類的皮膚；次外圍的 2根針則用來撐開皮膚；剩下的2根 針，一根稱為「尋找針」，它亦是一 條細長中空管子，不但用來尋找血 管的位置，也用來吸取血液；最後 一根稱為「下嚥針」，它的作用是將 唾液滴入人體。 蚊子的唾液含有一種化學物 質，名為「抗凝血酶」，這種物質可 以防止人體的血液凝固。抗凝血酶 會引起人體的免疫反應，令人體釋 放一種稱為「組織胺」的化學物質。 組織胺會引起血管擴張和增加血管 的通透性，令我們被叮的部位出現 紅腫。此外，組織胺亦會刺激神經 末梢，導致我們的痛覺神經傳遞增 加而感到疼痛或刺癢。而在免疫系 統的反應下，白血球亦有可能會被 吸引到被叮咬的部位，進一步加重 局部的炎症和紅腫症狀。 誰是蚊子 「心頭好」？ 據香港大學化學博士K Kwong 指出，蚊子的感應距離可分為3個階 段，首先由15至50米外，蚊子會沿 着高濃度二氧化碳的方向飛過去， 牠們本着「有碳便有人」的邏輯去尋 找目標。因此身形較肥胖的人，以 及新陳代謝較快的小孩和孕婦會更 容易招惹蚊子。 當蚊子飛到距離人體5至15米 時，便可以利用視覺、感應反差及 嗅覺去分辨人體氣味。人體皮膚上 的汗水有助細菌生長，細菌分解汗 水後的代謝物，也特別吸引到蚊 子，所以普遍大汗的人亦會較容易 招惹蚊子。最後，於距離人體0至0.2 米內，蚊子會利用紅外線以及味道 鎖定目標，在降落皮膚上時用腳感 應血管位置，從而作出殘酷一叮。 另外，有研究指O型血的人較 容易被蚊子叮，亦有說飲食習慣、 居住地及周圍環境都會影響惹蚊程 度，眾說紛紜，仍須更多研究。 所有蚊 都是吸血鬼？ 其實所有蚊子都是以花蜜及植 物汁液為食糧，不 過成熟的雌性蚊 子需要獲取蛋白 質支持卵子及卵 巢的發育，而血液 中含有大量的蛋白質和 其他營養素，因此雌性蚊子會 積極尋找獵物進行吸血活動。 相比之下，雄性蚊子並不需要 血液中的營養素來支持自己的 繁殖過程，僅靠花蜜及植物 汁液已足夠維持生命。因 此，雌蚊的口器比較尖銳 有力，能夠刺破皮膚吸 取血液，而雄蚊的口器 則更適合吸食植物汁液。 總括而言，雄蚊其 實是素食主義者，只有雌 蚊才會吸食人血，「最毒婦人 心」用來形容蚊子再貼切不過了！ 如何防止 蚊子叮咬？ 想要在大戰中取得勝利，我們 必須採取以下有效防禦措施︰ 1.清潔環境︰蚊子喜歡在潮濕、陰 暗的環境中繁殖，因此保持環境 清潔衞生，清除積水和雜草，可 以減少蚊子的數量。 2.保持身體清潔︰由於蚊子會被汗 水吸引，因此時常保持身體清 潔，勤洗澡，可以降低被蚊叮的 風險。 3.使用驅蚊劑︰市面上有很多種驅 蚊劑，包括化學驅蚊劑和天然驅 蚊劑，可以形成一種保護屏障， 阻止蚊子接近我們的皮膚。 4.使用天然驅蚊植物︰其中有一些 植物，例如香茅、薄荷、艾草 等，具有驅蚊效果，可以在家中 種植這些植物，或使用它們的精 油來驅蚊。 5.使用驅蚊工具︰點蚊香，使用驅 蚊手環、防蚊扣、捕蚊燈、電蚊 拍、超聲波驅蚊器。 6 使用防蚊網及蚊帳︰在門窗安裝 防蚊網，而在睡覺時再搭配蚊 帳，可以防止蚊子進入我們的睡 眠空間。 7.穿着淺色衣物︰蚊子對深色衣物 更感興趣，因此穿着淺色衣物可 以降低被蛟叮的風險。 蚊子雖然微不足道，但牠們卻 是我們不可忽視的敵人。蚊子其實 是多種嚴重疾病的傳播媒介，例如 瘧疾、登革熱、寨卡病毒及日本腦 炎等，每年全球有超過100萬人因 為蚊子傳播的疾病而死亡。 我們必須了解牠們的習性，掌 握有效的防禦策略，才能守護我們 的健康！ 小思考，大智慧 1.驅蚊和防曬產品，可以同時使用 嗎？ 2.坊間流傳用指甲在蚊叮紅腫處壓 出「十」字可以止癢，是否有效？ 3. 為甚麼打蚊子這樣困難？ 參考答案 1. 很多人不想被蚊叮同時，又不想 被烈日曬傷，所以會把驅蚊和防 曬產品「打孖」使用。其實美國疾 病控制及預防中心不建議同時使 用。如果需要使用兩種產品，可 以先塗上防曬產品，等待約15至 30分鐘，讓防曬產品完全被皮膚 吸收乾透後，才塗上驅蚊產品。 2. 坊間流傳用指甲在蚊叮紅腫處壓 出「十」字可以止癢，不過有皮膚 科醫生就指出，這個行為只能短 暫抑壓痕癢感，使用指甲反覆壓 印還可能造成破皮流血，釋放出 更多組織胺，反而更痕癢，更可 能令患處留下疤痕！ 3. 專家解釋，一般人看到蚊子的時 候，通常是以雙手合掌，即雙手 左右合併拍擊的方式，但這個動 作會產生向外的氣流，反倒成為 蚊子向上逃脫的助力。正確打蚊 的方式，應該用「上下合掌」的方 式夾擊，這種「鋪天蓋地，上下 夾攻」的手勢，可以包圍蚊子， 降低牠們逃走的機會。 夜幕低垂，燈火通明的城市宛如一張美麗的蕾 絲織品，散發出迷人的光彩。一隻蚊子悄悄地闖進 我的家中，隱藏在一角虎視眈眈。在確定我熟睡後， 「蚊」型戰機立即發動襲擊，刺痛感瞬間傳遍全身， 猛然驚醒，卻發現那個幕後黑手已飛走無蹤，令我無 法好好入睡。一覺醒來，身上只留下一個個紅腫的印 記！痛定思痛，正所謂「知己知彼，百戰百勝」，要 在這場人蚊大戰中獲勝，我必須好好了解敵軍，作出 部署，才能跟牠們一決高下！ 星島教室 生物 鄭俊傑 中華基督教會 協和小學（長沙灣） 副校長 作者介紹 讀社論學 英文 G l ob a l h i g h e r e du c a t i on n e t wo r k Quacquarelli Symonds (QS) has just released the World University Rankings 2025 with the positions of six Hong Kong universities rising significantly. This is undoubtedly a booster for building an international higher education hub. Although everything is in place, there is still a lot to be done in building the "Study in Hong Kong" initiative into an industry chain. Student accommodation is one of the issues. Unleashing potential to generate income The QS assessed 1,500 universities in 106 higher education systems using nine indicators. Seven Hong Kong universities were on the list with six of them significantly higher than last year. The University of Hong Kong (HKU) ranked the highest at 17th, a record high, while the Chinese University of Hong Kong and Polytechnic University also reached historical marks. Hong Kong not only is one of the most reputable academically but also scores high in the international faculty and student ratios, reflecting its influence in research and international ization edge. HKU is ranked 14th in employment outcomes , ref lect ing high recognition of its bachelor's degrees by employers. Students have no worries about their career prospect. The ranking reaffirms that Hong Kong is one of the most well-established, recognized and upgraded higher education systems. These can help the city develop into an international education hub to attract more overseas and mainland students. If the authori t ies can capitalize on these to gradually build up the "Study in Hong Kong" initiative and form an industry chain to unleash its potentials, it will bring huge benefits, including increased tuition fees and rental revenues, in par with traditional study destinations such as the UK and Australia. The 600,000 overseas students enrolled in UK universities in the 2020/21 academic year brought £41.9 billion (HK$418.3 billion) to the country, while over 600,000 enrolled in Australia in 2022 earned AUS$29 billion (HK$150.6 billion). Because of the great pot ent i a l , the government in last year ' s Pol icy Address proposed developing Hong Kong into an international higher education hub by doubling the non-local student quotas of the eight government-f inanced inst i tut ions from 20 to 40 per cent in the new academic year in September. That is to say, 3,000 non-local students will increase to 6,000. Self-financing institutions even do not have a quota, which means more overseas students . However, expansion is not enough. It is also necessary to do a good job in supporting facilities, especially accommodation. Student quarters in the eight major universities and self-financing institutions have always fallen short of demand. In the 2022/23 academic year, the number of students was as high as 253,000, but there were a total of 39,000 hostel places to serve only 16 per cent of them. Locals can live with their parents but those from overseas have to rent private flats leading to a boom in the market. Even though property prices have dropped by about 13 per cent last year, student rentals have risen by 15 per cent. With the influx of non-local students in the new school year, a real estate agent has estimated that there will be an additional demand for over 22,000 bedspaces in the next four years. An investor with insight has recently partnered with an operator to purchase a hotel building to be converted into a student dormitory. Centaline Investments has indicated that it is investing in 2,000 student hostel rooms in the next two years. Use idle school premises & land sale conditions These people, after al l, make profits, raising rents at contract expiry. Many nonlocal students who wish to study here may be deterred by the high cost of living. Even if the institutions can identify sites in the vicinity of their campuses or negotiate for the purchase of hotels, construction and conversion take time. This cannot quench the urgent demand. It is thus necessary to build affordable quarters. For example, vacant school premises can be converted and land sale conditions stipulate that developments include a certain percentage of student hostels enhancing public-private partnership to resolve the shortage. As there are differences in language and culture, institutions should increase manpower and foster tolerance to help non-local students integrate into Hong Kong life while providing counselling to enhance their sense of belonging, which will be conducive to developing their career after graduation. So there will be enough talents to sustain its development. 翻譯自6月6日《星島日報》社論 （http://std.stheadline.com/） 1. The word _____ in the first paragraph is the opposite of "questionably". 2. HKU graduates have no worries about their career _____. 3. In the passage, the word _____ means "rebuilt". 4. Building new student accommodation takes _____. 5. According to the last paragraph, institutions should provide _____ to overseas students. Answers 1. undoubtedly / significantly 2. prospect 3. converted 4. time 5. counselling & Q A booster (n) ——強心針 prospect (n) ——前景 reaffirm (v) ——再肯定 unleash (v) ——釋放 boom (n) ——繁榮期 bedspace (n) ——床位 conversion (n) ——改建 quench (v) ——滿足 Vocabulary supporting facility —— 配套 contract expiry —— 約滿 land sale condition —— 賣地條款 public-private partnership —— 公私營合作 Useful Terms QS senior v i ce pres ident Ben Sowter said that Hong Kong universi t ies "stand out as one of the most improved in the wor ld" . "The ci ty's universities, spearheaded by the University of Hong Kong, achieved signi f icant gains in i ts employer reputation and research," Sowter said. Hong Kong and Singapore are the only two territories with an average academic reputation score above 50 out of 100. Did you know? All ready for higher education hub but accommodation 翻譯︰George D6 侷芎 01.29.2025 星期三
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