Effective Theories for Circuits and Automata

Abstracting an effective theory from a complicated process is central to the study of complexity. Even when the underlying mechanisms are understood, or at least measurable, the presence of dissipation and irreversibility in biological, computational and social systems makes the problem harder. Here we demonstrate the construction of effective theories in the presence of both irreversibility and noise, in a dynamical model with underlying feedback. We use the Krohn-Rhodes theorem to show how the composition of underlying mechanisms can lead to innovations in the emergent effective theory. We show how dissipation and irreversibility fundamentally limit the lifetimes of these emergent structures, even though, on short timescales, the group properties may be enriched compared to their noiseless counterparts.Comment: 11 pages, 9 figure

Ponderomotive Acceleration by Relativistic Waves

In the extreme high intensity regime of electromagnetic (EM) waves in plasma, the acceleration process is found to be dominated by the ponderomotive acceleration (PA). While the wakefields driven by the ponderomotive force of the relativistic intensity EM waves are important, they may be overtaken by the PA itself in the extreme high intensity regime when the dimensionless vector potential $a_0$ of the EM waves far exceeds unity. The energy gain by this regime (in 1D) is shown to be (approximately) proportional to $a_0^2$. Before reaching this extreme regime, the coexistence of the PA and the wakefield acceleration (WA) is observed where the wave structures driven by the wakefields show the phenomenon of multiple and folded wave-breakings. Investigated are various signatures of the acceleration processes such as the dependence on the mass ratio for the energy gain as well as the energy spectral features. The relevance to high energy cosmic ray acceleration and to the relativistic laser acceleration is considered.Comment: 15 pages, 7 figures. This is an author-created, un-copyedited version of an article submitted for publication in Physical Review ST Accelerators and Beam

Image-Guided Ablative Therapies for Lung Tumors

While the gold standard for early stage lung cancers is still surgical resection, many patients have comorbidities or suboptimal lung function making surgery unfavorable. At the same time, more and more small lung nodules are being incidentally discovered on computer tomography (CT), leading to the discovery of pre-malignant or very early stage lung cancers without regional spread, which could probably be eradicated without anatomical surgical resection. Various ablative energies and technologies are available on the market, including radiofrequency ablation, microwave ablation, cryoablation, and less commonly laser ablation and irreversible electroporation. For each technology, the mechanism of action, advantages, limitations, potential complications and evidence-based outcomes will be reviewed. Traditionally, these ablative therapies were done under CT guidance with percutaneous insertion of ablative probes. Recently, bronchoscopic ablation under ultrasound, CT, or electromagnetic navigation bronchoscopy guidance is gaining popularity due to improved navigation precision, reduced pleural-based complications, and providing a true “wound-less” option

A profile of the online dissemination of national influenza surveillance data

<p>Abstract</p> <p>Background</p> <p>Influenza surveillance systems provide important and timely information to health service providers on trends in the circulation of influenza virus and other upper respiratory tract infections. Online dissemination of surveillance data is useful for risk communication to health care professionals, the media and the general public. We reviewed national influenza surveillance websites from around the world to describe the main features of surveillance data dissemination.</p> <p>Methods</p> <p>We searched for national influenza surveillance websites for every country and reviewed the resulting sites where available during the period from November 2008 through February 2009. Literature about influenza surveillance was searched at MEDLINE for relevant hyperlinks to related websites. Non-English websites were translated into English using human translators or Google language tools.</p> <p>Results</p> <p>A total of 70 national influenza surveillance websites were identified. The percentage of developing countries with surveillance websites was lower than that of developed countries (22% versus 57% respectively). Most of the websites (74%) were in English or provided an English version. The most common surveillance methods included influenza-like illness consultation rates in primary care settings (89%) and laboratory surveillance (44%). Most websites (70%) provided data within a static report format and 66% of the websites provided data with at least weekly resolution.</p> <p>Conclusion</p> <p>Appropriate dissemination of surveillance data is important to maximize the utility of collected data. There may be room for improvement in the style and content of the dissemination of influenza data to health care professionals and the general public.</p

Effects of School Closures, 2008 Winter Influenza Season, Hong Kong

In winter 2008, kindergartens and primary schools in Hong Kong were closed for 2 weeks after media coverage indicated that 3 children had died, apparently from influenza. We examined prospective influenza surveillance data before, during, and after the closure. We did not find a substantial effect on community transmission

Powering the ABC multidrug exporter LmrA: How nucleotides embrace the ion-motive force.

LmrA is a bacterial ATP-binding cassette (ABC) multidrug exporter that uses metabolic energy to transport ions, cytotoxic drugs, and lipids. Voltage clamping in a Port-a-Patch was used to monitor electrical currents associated with the transport of monovalent cationic HEPES+ by single-LmrA transporters and ensembles of transporters. In these experiments, one proton and one chloride ion are effluxed together with each HEPES+ ion out of the inner compartment, whereas two sodium ions are transported into this compartment. Consequently, the sodium-motive force (interior negative and low) can drive this electrogenic ion exchange mechanism in cells under physiological conditions. The same mechanism is also relevant for the efflux of monovalent cationic ethidium, a typical multidrug transporter substrate. Studies in the presence of Mg-ATP (adenosine 5'-triphosphate) show that ion-coupled HEPES+ transport is associated with ATP-bound LmrA, whereas ion-coupled ethidium transport requires ATP binding and hydrolysis. HEPES+ is highly soluble in a water-based environment, whereas ethidium has a strong preference for residence in the water-repelling plasma membrane. We conclude that the mechanism of the ABC transporter LmrA is fundamentally related to that of an ion antiporter that uses extra steps (ATP binding and hydrolysis) to retrieve and transport membrane-soluble substrates from the phospholipid bilayer.This research was supported by the Biotechnology and Biological Sciences Research Council grants BB/R00224X/1, BB/I002383/1 and BB/K017713/1, and Medical Research Council grant G0401165 (to H.W.V.V.). We are also grateful for funding by the Human Frontier Science Program (grant RGP0034/2013), Strategic International Cooperative Program (Japan Science and Technology Agency, Japan) and Royal Society (UK) for collaborative research between H.W.V.V. and S.M. C.H.F.L. received a research studentship of Peterhouse, Cambridge. Y.S.K.K. received a Federal Training Award from the Ministry of Health in Malaysia. H.S. and S.R. were supported by the Cambridge Commonwealth, European and International Trust

沒有年齡的課室 : 成效評估研究報告

背景 香港人口老齡化的趨勢持續加劇，傳統的家庭照顧模式已難以滿足老年人和幼童在身心發展上的需求，需要探索新的跨代互助模式。因此，和悅社會企業於2023 年夏季舉辦了一項名為「沒有年齡的課室」的計劃（以下簡稱「計劃」/「課程」）。該課程旨在為長者及幼童提供共學的機會，推動跨代連結與互惠。為了更客觀地檢視「沒有年齡的課室」的實施情況與成效，以及探討在香港推行跨代共學的可行性，和悅社會企業委託嶺南大學亞太老年學研究中心對該課程進行了評估研究，並撰寫了此報告以供相關持分者參考。 研究方法 2. 研究採用定量研究及定性研究的數據收集和分析的混合研究法 (Mixed Methods) 進行。除了透過問卷調查和聚焦小組去收集參加者對課程的看法外，同時分析課程的數據、進行實地觀察，以及檢視相關文獻資料，從而更全面地瞭解整個課程的實施情況、對參與者的影響，以及探討計劃未來的發展方向。 研究結果 3. 本研究於2023年6月至9月期間成功對實驗組及對照組參加者進行了兩輪問卷調查，收集參加者的意見。調查結果顯示，長者及幼童的家長讓他們的孩子參與計劃的最主要原因是為了「想學習新知識 」(長者學員：72%；幼童：73%)，其次為「進行跨代接觸交流」 (長者學員：60%；幼童家長：54%)，第三個主要原因是可以「嘗試新事物」(長者學員：40%；幼童：54%)，以及可以「認識新朋友」 (長者學員：36%；幼童家長：50%)。至於計劃對參加者的影響方面，本研究透過比較實驗組 (即參加「沒有年齡的課室」的長者及幼童學員) 與對照組 (即課程無長幼共學成份)參加者在對雙方態度、自尊心及自信、社交技巧等方面的前後變化。從分析結果顯示，長幼學員在修畢本課程後，對彼此的態度 (長者學員對幼童態度：實驗組增長17%，對照組下降1%；幼童學員對長者態度：實驗組增長19%，對照組增長7%) 及幼童學員的社交技巧 (實驗組增長9%，對照組增長1%) 之增長達統計學顯著程度，足見本課程成功透過長幼共學的方式去改善長幼對彼此的觀感和態度。至於對課程的體驗方面，長者學員及幼童學員之家長均給予高度評價和評分，以1-7分為量表去評價，參加者普遍對課程感到十分滿意 (長者學員：平均分為6.07分；幼童學員：6.29分)、並表示若和悅社會企業日後舉行類似課程會再次參加(長者學員：平均分為5.33分；幼童學員：6.41分) 和向別人推薦此類課程 (長者學員：平均分為5.33分；幼童學員：6.29分)。概括而言，從統計結果反映了課程為參加者帶來很多正面影響，特別是長者或幼童態度之改善比沒有跨代共學成份的課程更為顯著。 4. 此外，本研究邀請了參與課程的長者、幼童家長、和推行「沒有年齡的課室」計劃的同工進行了3 場聚焦小組以深化對問卷調查結果，並進一步探討可如何改善計劃之推行及在社區推廣跨代共學的模式。從結果顯示，長幼學員透過參與本課程互相接觸及互動，增加彼此了解，使彼此的觀感及態度亦變得正面，達到促進跨代共融的目標。同時，幼童的社交技巧、接觸長者的動機及幼童的個人成長亦有所提升。長幼學員、課程導師及項目統籌人員均表示參加者能愉快地學習和十分享受參與本課程。 5. 從不同的的數據作綜合分析，促進「沒有年齡的課室」的成功因素包括: (i) 1對1的長幼配對，增加長幼學員之互動機會以便建立互信關係以及日後的情感聯繫； (ii) 課程時間節數安排要配合幼童的學習時間表 (如與暑假活動分開、每堂時數能讓幼童學員專心等) ；及 (iii) 招募適合的參加者，以其年齡、興趣喜好及性別進行配對 (如女性參加者明顯更為適合參與此類以幼童為對象的活動計劃)。 6. 關於課程的未來發展，研究建議推行機構可考慮以下5 個要點：(i) 除以1對1長幼配對外，亦可考慮同時加入1位長者對數名幼童，或1名幼童對數名長者的混合模式，這樣可以增加長幼學員與不同參加者的互動機會，進一步培養社交技巧；(ii) 可增加針對長者學員的課程內容 ，讓長者以學生身份投入各個課程活動；(iii) 讓一些能力比較高的長者參與課程設計及教材 (如讓長者準備自己過去相片與幼童分享過去時代點滴生活)，為長者充權；(iv) 微調課堂時間以配合長者的活動時間表 (如可參考現時日間長者中心的活動時間)；及 (v) 增加人手安排編制至5至8人，以便在推行活動過程中提供適時的支援 (如增設社工以應付課堂上幼童學員突發的情緒問題)。 總結 7. 綜合各種數數據證明「沒有年齡的課室」有效促進跨代共學與互助，為長者建立正面形象、提升他們的生活質素、亦能令幼童認識如何與長者溝通，改善社交技巧以及提升自尊感等。因此，其他長者服務機構、企業及教育團體可以仿傚此活動，在幼稚園 (即幼兒期) 便引入跨代共學的元素，促進代際間情感、知識與文化的傳遞，重塑「老吾老以及人之老，幼吾幼以及人之幼」的價值觀，建立一個強調代間互助和共融的社會