Direct conversion of an oligopeptide from a β-sheet to an α-helix: A model for amyloid formation

A 16-amino acid oligopeptide forms a stable β-sheet structure in water. In physiological solutions it is able to self-assemble to form a macroscopic matrix that stains with Congo red. On raising the temperature of the aqueous solution above 70°C, an abrupt structural transition occurs in the CD spectra from a β-sheet to a stable α-helix without a detectable random-coil intermediate. With cooling, it retained the α-helical form and took several weeks at room temperature to partially return to the β-sheet form. Slow formation of the stable β-sheet structure thus shows kinetic irreversibility. Such a formation of very stable β-sheet structures is found in the amyloid of a number of neurological diseases. This oligopeptide could be a model system for studying the protein conformational changes that occurs in scrapie or Alzheimer disease. The abrupt and direct conversion from a β-sheet to an α-helix may also be found in other processes, such as protein folding and protein–protein interaction. Furthermore, such drastic structure changes may also be exploited in biomaterials designed as sensors to detect environmental changes.

A catalogue of books in the College library: [which Benjamin Welles wished to read], 1797

In this small paper-bound catalog, Benjamin Welles (1781-1860) listed books in the Harvard College Library which he wished to read. He presumably compiled the list by consulting the Library's 1790 printed catalog, as the works are categorized according to subjects outlined in that catalog (Antiquities, Astronomy, Ancient Authors, Biography, Sacred Criticism, Ethics, Geography, Geometry, History, Nature, Travels / Voyages, Natural Law, Logic, Metaphysics, Miscellaneous Works, Dramatic, Phililogy, Natural Philosophy, Poetry, Rhetoric, and Theology). The final pages of Welles' catalog, which he titles "Another Selection," list additional volumes he wished to read. These are listed alphabetically, A - G. Some titles throughout the catalog have been marked with a "+" perhaps to indicate that Welles had read them.

Letters from Delia Jarvis Tudor to her son, William Tudor,

Five letters sent from Gardiner, Maine, Boston, and New York. In several, there are messages included from Emma and Robert Hallowell Gardiner. One letter includes anectdotes regarding the late William Tudor and the American Revolution. One letter written to Tudor while he was chargé d’affairs in Rio de Janeiro relates news that his brother, Henry James (Harry), was setting up a salt-making business; it also includes a message from Delia, anticipating his return to the United States. Two additional undated letters, addressed to Tudor in Portsmouth, New Hampshire, likely before Tudor’s father died in 1819, contain family news and local gossip.

Letter from Samuel Willard, Harvard College, Cambridge, Massachusetts, to William Willard and Katherine Willard, Petersham, Massachusetts, April 4, 1801

Willard informs his parents of the death of Deacon Fairbank. He assures them that on his return to Cambridge, he was “received with great apparent cordiality both by the government + the president’s family.” He also reports on the health of President Willard, whose health has improved. Willard concludes the letter by asking for money to pay his expenses.

Letters from Benjamin Welles to John Henry Tudor, 1799-1801

Benjamin Welles wrote these six letters to his friend and classmate, John Henry Tudor, between 1799 and 1801. Four of the letters are dated, and the dates of the other two can be deduced from their contents. Welles wrote Tudor four times in September 1799, at the onset of their senior year at Harvard, in an attempt to clear up hurt feelings and false rumors that he believed had caused a chill in their friendship. The cause of the rift is never fully explained, though Welles alludes to "a viper" and "villainous hypocrite" who apparently spread rumors and fueled discord between the two friends. In one letter, Welles asserts that "College is a rascal's Elysium - or the feeling man's hell." In another he writes: "College, Tudor, is a furnace to the phlegmatic, & a Greenland to thee feeling man; it has an atmosphere which breathes contagion to the soul [...] Villains fatten here. College is the embryo of hell." Whatever their discord, the wounds were apparently eventually healed; in a letter written June 26, 1800, Welles writes to ask Tudor about his impending speech at Commencement exercises. In an October 29, 1801 letter, Welles writes to Tudor in Philadelphia (where he appears to have traveled in attempts to recover his failing health) and expresses strong wishes for his friend's recovery and return to Boston. This letter also contains news of their classmate Washington Allston's meeting with painters Henry Fuseli and Benjamin West.

From stabilisation to stagnation. Viktor Yanukovych's reforms. OSW Point of View Number 32, March 2013

After winning the 2010 presidential election, Viktor Yanukovych and his government developed an ambitious and comprehensive programme of reforms across key areas of social and political life. The return to a presidential system of government created the ideal conditions for the introduction of deep reforms: it allowed Viktor Yanukovych to consolidate more power than any other Ukrainian president before him.The authorities launched an overhaul of the tax and the pension systems, and of the Ukrainian gas sector. Kyiv also completed its negotiations on an Association Agreement with the EU and on a Deep and Comprehensive Free Trade Area. However, the reformist zeal of Ukraine’s political elite progressively diminished as the parliamentary election approached, the economy slowed down, and the polls showed a decline in support for the ruling Party of Regions. Many of the reforms still remain in the planning stages, and in many areas the government has moved backwards. Viktor Yanukovych has proved unable to make systemic changes, and has increasingly used his powers to crush political opposition in Ukraine. The outcome of the latest parliamentary elections prevents the formation of a stable parliamentary majority, which in turn, removes any chance of reform before the 2015 presidential ballot.

The 2015 National Elections in Switzerland: Renewed Polarization and Shift to the Right

The 2015 election to the Swiss Parliament marks a return to an already observed trend that was only interrupted in 2011: a shift to the right and an increase in polarization. The vote share of the nationalist-conservative Swiss People's Party (SVP) has now reached a historical height of 29.4% (+2.8). This note discusses why cantons matter in the Swiss national elections, and to what degree elections have become nationalized. Institutionally, the 26 cantons serve as electoral districts. This leads to a highly disproportional electoral system and has magnified the minor vote shifts to a slightly more pronounced shift in seats, with the right now holding a tiny majority of 101 of 200 seats in the first chamber. The two winners, the SVP and the Liberals, also had most campaign funds at their disposal. They were able to guide an extensive nationwide campaign in which they advocated their core issues instead of candidates. Other parties only advertised at the cantonal level.

Report from the Select committee on Post office (Telephone agreement), 1905; together with the proceedings of the committee, minutes of evidence, and appendix. Ordered, by the House of commons, to be printed, 31 July 1905.

Postmaster general and National telephone company. Return to an order of the Honourable the House of commons, dated 14 February 1905;--for, copy of memorandum ... setting forth an agreement, dated 2nd February 1905, between the postmaster general and the National telephone company, limited": [v. 1] p. xiii-[xxxviii]

Return of the recent survey and report of the engineers on the Ottawa ship canal.

Return to an address from the Legislative assembly to the governor general.

Phototoxicity of photosystem II (PSII) herbicides to coral

Recent reports of contamination of the Great Barrier Reef Marine Park by herbicides used in antifouling paints and in agriculture have caused concern over the possible effects on corals in nearshore areas. Pulse-Amplitude Modulated (PAM) chlorophyll fluorescence techniques were used to examine changes in the maximum effective quantum yield (ΔF/Fm′) of symbiotic dinoflagellates within the host tissues (in hospite) of the coral Seriatopora hystrix exposed to a number of Photosystem II (PSII) inhibiting herbicides in short-term toxicity tests. The concentration of herbicide required to reduce ΔF/Fm′ by 50% (median effective concentration [EC50]) differed by over 2 orders of magnitude: Irgarol 1051 (0.7 μg l-1) > ametryn (1.7 μg l-1) > diuron (2.3 μg l-1) > hexazinone (8.8 μg l -1) > atrazine (45 μg l-1) > simazine (150 μg l-1) > tebuthiuron (175 μg l-1) > ionynil (> 1 mg l-1). Similar absolute and relative toxicities were observed with colonies of the coral Acropora formosa (Irgarol 1051 EC50: 1.3 μg l-1, diuron EC50: 2.8 μg l-1), Time-course experiments indicated that ΔF/Fm′ was rapidly reduced (i.e. within minutes) in S. hystrix exposed to Irgarol 1051 and diuron. On return to fresh running seawater, ΔF/Fm′ recovered quickly in diuron-exposed corals (i.e. in minutes to hours), but slowly in corals exposed to Irgarol 1051 (i.e. hours to days). Time-course experiments indicated that the effects of diuron (3 μg l-1) on S. hystrix were inversely related to temperature over the range 20 to 30 °C, although initially the effects were less at the lower temperatures. Repeated exposure to pulses of Irgarol 1051 (daily 2 h exposure to 30 μg l -1 over 4 d) resulted in a 30% decrease in the density of symbiotic dinoflagellates in the tissues of S. hystrix.

Achieving completeness: from constructive set theory to large cardinals

This thesis is an exploration of several completeness phenomena, both in the constructive and the classical settings. After some introductory chapters in the first part of the thesis where we outline the background used later on, the constructive part contains a categorical formulation of several constructive completeness theorems available in the literature, but presented here in an unified framework. We develop them within a constructive reverse mathematical viewpoint, highlighting the metatheory used in each case and the strength of the corresponding completeness theorems. The classical part of the thesis focuses on infinitary intuitionistic propositional and predicate logic. We consider a propositional axiomatic system with a special distributivity rule that is enough to prove a completeness theorem, and we introduce weakly compact cardinals as the adequate metatheoretical assumption for this development. Finally, we return to the categorical formulation focusing this time on infinitary first-order intuitionistic logic. We propose a first-order system with a special rule, transfinite transitivity, that embodies both distributivity as well as a form of dependent choice, and study the extent to which completeness theorems can be established. We prove completeness using a weakly compact cardinal, and, like in the constructive part, we study disjunction-free fragments as well. The assumption of weak compactness is shown to be essential for the completeness theorems to hold.

Is ICT key to development?

Using panel data for 52 developed and developing countries over the period 1998-2006, this article examines the links between information and communication technology diffusion and human development. We conducted a panel regression analysis of the investments per capita in healthcare, education and information and communication technology against human development index scores. Using a quantile regression approach, our findings suggest that changes in healthcare, education and information and communication technology provision have a stronger impact on human development index scores for less developed than for highly developed countries. Furthermore, at lower levels of development education fosters development directly and also indirectly through their enhanced effects on ICT. At higher levels of development education has only an indirect effect on development through the return to ICT.

A comparison of the vocational training system of Britain and West Germany as experienced by minimum-age school leavers.

The sectoral and occupational structure of Britain and West Germany has increasingly changed over the last fifty years from a manual manufacturing based to a non-manual service sector based one. There has been a trend towards more managerial and less menial type occupations. Britain employs a higher proportion of its population in the service sector than in manufacturing compared to West Germany, except in retailing, where West Germany employs twice as many people as Britain. This is a stable sector of the economy in terms of employment, but the requirements of the workforce have changed in line with changes in the industry in both countries. School leavers in the two countries, faced with the same options (FE, training schemes or employment) have opted for the various options in different proportions: young Germans are staying longer in education before embarking on training and young Britons are now less likely to go straight into employment than ten years ago. Training is becoming more accepted as the normal route into employment with government policy leading the way, but public opinion still slow to respond. This study investigates how vocational training has adapted to the changing requirements of industry, often determined by technological advancements. In some areas e.g. manufacturing industry the changes have been radical, in others such as retailing they have not, but skill requirements, not necessarily influenced by technology have changed. Social-communicative skills, frequently not even considered skills and therefore not included in training are coming to the forefront. Vocational training has adapted differently in the two countries: in West Germany on the basis of an established over-defined system and in Britain on the basis of an out-dated ill-defined and almost non-existent system. In retailing German school leavers opt for two or three year apprenticeships whereas British school leavers are offered employment with or without formalised training. The publicly held view of the occupation of sales assistant is one of low-level skill, low intellectual demands and a job anyone can do. The traditional skills - product knowledge, selling and social-communicative skills have steadily been eroded. In the last five years retailers have recognised that a return to customer service, utilising the traditional skills was going to be needed of their staff to remain competitive. This requires training. The German retail training system responded by adapting its training regulations in a long consultative process, whereas the British experimented with YTS, a formalised training scheme nationwide being a new departure. The thesis evaluates the changes in these regulations. The case studies in four retail outlets demonstrate that it is indeed product knowledge and selling and social-communicative skills which are fundamental to being a successful and content sales assistant in either country. When the skills are recognised and taught well and systematically the foundations for career development in retailing are laid in a labour market which is continually looking for better qualified workers. Training, when planned and conducted professionally is appreciated by staff and customers and of benefit to the company. In retailing not enough systematic training, to recognisable standards is carried out in Britain, whereas in West Germany the training system is nevertheless better prepared to show innovative potential as a structure and is in place on which to build. In Britain the reputation of the individual company has a greater role to play, not ensuring a national provision of good training in retailing.

All-optical 42.6 Gbit/s NRZ to RZ format conversion by cross-phase modulation in single SOA

A 42.6 Gbit/s all-optical non-retum-to-zero (NRZ) to return-to-zero (RZ) format converter using a single SOA followed by an asymmetrical Mach-Zehnder interferometer is presented. The format converter generates a correctly-coded RZ signal with a controllable duty-cycle. It has the advantages of flexible input N RZ wavelength, preserved input polarity, negative bit error rate power penalty and low switching pulse energy (15fJ).

Simultaneous multiple channel all-optical NRZ to CSRZ and RZ to CSRZ format conversion using an SOA-NOLM

The optical conversion bandwidth for an all-optical modulation format converter, based on a semiconductor laser amplifier in a nonlinear optical loop mirror (SOA-NOLM), is investigated. 4 Â 10 Gbit/s channels are all- optically converted between both non-return-to-zero (NRZ) and return-to-zero (RZ) format to carrier- suppressed return-to-zero (CSRZ). WDM transmission of the converted signals over a 194 km fibre span is then demonstrated. The receiver sensitivity for the converted four wavelengths is measured and compared after transmission.