Light emission from gold and silver thin films in a scanning tunneling microscope: role of contamination and interpretation of grain structure in photon maps

Scanning tunnelling microscope (STM) tip-induced light emission from Au and Ag has been studied. Thin film samples similar to100nm thick were prepared by thermal evaporation at 0.5nm/s onto a room-temperature glass substrate to produce grains of 20-50nm in lateral dimension at the surface. Light emission from the samples in the STM was quasi-simultaneously recorded with the topography, at 1.8V tip bias and 3-40nA current, alternating pixel by pixel at the same bias. Typically, a surface scan range of 150 nm x 150 nm was surveyed. Au, W and PtIr tips were used.

Assessing the evidence: Student response system versus computer based testing for undertaking multiple choice question assessment in undergraduate nursing education

There is a dearth of evidence focusing on student preferences for computer-based testing versus
testing via student response systems for summative assessment in undergraduate education.
This quantitative study compared the preference and acceptability of computer-based testing
and a student response system for completing multiple choice questions in undergraduate
nursing education. After using both computer-based testing and a student response system to
complete multiple choice questions, 192 first year undergraduate nursing students rated their
preferences and attitudes towards using computer-based testing and a student response system.
Results indicated that seventy four percent felt the student response system was easy to use.
Fifty six percent felt the student response system took more time than the computer-based testing
to become familiar with. Sixty Percent felt computer-based testing was more users friendly.
Seventy Percent of students would prefer to take a multiple choice question summative exam
via computer-based testing, although Fifty percent would be happy to take using student response
system. Results are useful for undergraduate educators in relation to student’s preference
for using computer-based testing or student response system to undertake a summative
multiple choice question exam

Silver nanoparticles flow in an aquatic trophic chain

Silver nanoparticles (AgNP) have been produced and applied in a variety of products ranging from personal care products to food package containers, clothing and medicine utilities. The antimicrobial function of AgNP makes it very useful to be applied for such purposes. Silver (Ag) is a non-essential metal for organisms, and it has been historically present in the environment at low concentrations. Those concentrations of silver increased in the last century due to the use of Ag in the photographic industry and lately are expected to increase due to the use of AgNPs in consumer products. The presence of AgNP in the aquatic environment may pose a risk for aquatic species, and the effects can vary from lethal to sublethal effects. Moreover, the contact of aquatic organisms with AgNP may not cause immediately the death of individuals but it can be accumulated inside the animals and consequently transferred within the food chain. Considering this, the objective of this work was to study the transfer of silver nanoparticles in comparison to silver ions, which was used as silver nitrate, within an aquatic food chain model. To achieve this goal, this study was divided into four steps: the toxicity assessment of AgNP and AgNO3 to aquatic test-species, the bioaccumulation assessment of AgNP and AgNO3 by Pseudokirchneriella subcapitata and Daphnia magna under different exposure scenarios, and finally the evaluation of the trophic transfer of Ag through an experimental design that included the goldfish Carassius auratus in a model trophic chain in which all the species were exposed to the worse-case scenario. We observed that the bioconcentration of Ag by P. subcapitata is mainly driven by ionic silver, and that algae cannot internalize these AgNPs, but it does internalizes dissolved Ag. Daphnia magna was exposed to AgNP and AgNO3 through different exposure routes: water, food and both water and food. The worse-case scenario for Daphnia Ag bioaccumulation was by the joint exposure of contaminated water and food, showing that Ag body burdens were higher for AgNPs than for AgNO3. Finally, by exposing C. auratus for 10 days through contaminated water and food (supplied as D. magna), with another 7 days of depuration phase, it was concluded that the 10 days of exposure were not enough for fish to reach a plateau on Ag internal concentration, and neither the 7 days of elimination were sufficient to cause total depuration of the accumulated Ag. Moreover, a higher concentration of Ag was found in the intestine of fish when compared with other organs, and the elimination rate constant of AgNP in the intestine was very low. Although a potential for trophic transfer of AgNP cannot be suggested based in the data acquired in this study, there is still a potential environmental risk for aquatic species.

The sectionalism of the tariff bill. Speech of Hon. John L. McLaurin, of South Carolina, in the Senate of the United States

This document contains a speech by John L. McLaurin, representative of South Carolina. Sections of the speech include: sectionalism exposed, the bill might have been defeated, the south plundered of its rights, not a protectionist, fraudulent demands of New England, Hon. Randolph Tucker, Hon. W.R. Morrison, and Hon. R.Q. Mills strangers to the doctrine in 1882, a tariff for revenue against the doctrine of free raw material, don’t want Cleveland’s interpretation, contest of schedules, and my remedy.

The tariff. Speech of Representative J. L. McLaurin, of South Carolina, in the House of Representatives, Tuesday, March 23, 1897

This document contains a speech of John L. McLaurin, representative of South Carolina, in the House of Representatives on Tuesday, March 23, 1897 about proposed tariffs.

Protection to farmers : speech of Hon. D. Wyatt Aiken, of South Carolina, in the House of Representatives, Tuesday, March 6, 1882, upon the Agricultural Appropriation Bill

This speech is about the Agricultural Appropriation Bill, which is a bill making appropriations for the Agricultural Department of the Government for the fiscal year ending in June 30,1883. Mr. Aiken is approved by the chairman to speak and he goes on to explain that he agrees with the majority of the bill with the exception of two or three clauses. He gives the reasoning behind his objections in the rest of the speech.

Synthesis of nanoporous materials for preconcentration and determination of trace elements by ICP-AES ; Investigation and elimination of the memory effects of mercury, gold, silver and boron in ICP-AES

Nanoporous materials with large surface area and well-ordered pore structure have been synthesized. Thiol groups were grafted on the materials' surface to make heavy metal ion pre-concentration media. The adsorption properties ofthe materials were explored. Mercury, gold and silver can be strongly adsorbed by these materials, even in the presence of alkaline earth metal ion. Though the materials can adsorb other heavy metal ions such as lead and copper, they show differential adsorption ability when several ions are present in solution. The adsorption sequence is: mercury> == silver> copper » lead and cadmium. In the second part of this work, the memory effects of mercury, gold, silver and boron were investigated. The addition of 2% L-cysteine and 1% thiourea eliminates the problems of the three metal ions completely. The wash-out time for mercury dropped from more than 20 minutes to 18 seconds, and the wash-out time for gold decreased from more than 30 minutes to 49 seconds. The memory effect of boron can be reduced by the use of mannitol.

Why are we still at war? : or, The American question considered ; in a series of essays rejected by the journalists as unpopular ; recommended to a candid perusal /

In the Pamphleteer, vol. 4, p. 551-576. London, 1814.

Why are we still at war? : or, The American question considered ; in a series of essays rejected by the journalists as unpopular ; recommended to a candid perusal

In the Pamphleteer, vol. 4, p. 551-576. London, 1814

Silver Nanoparticles Obtained in PAH/PAA-Based Multilayers by Photochemical Reaction

Carboxylic acid groups in PAH/PAA-based multilayers bind silver cations by ion exchange with the acid protons. The aggregation and spatial distribution of the nanoparticles proved to be dependent oil the process used to reduce the silver acetate aqueous solution. The reducing method with ambient light formed larger nanoparticles with diameters ranging from 4-50 nm in comparison with the reduction method using UV light, which gave particles with diameters of 2-4 nm The high toughness of samples reduced by ambient light is a result of two population distributions of particle sizes caused by different mechanisms when compared with the UV light process. According to these phenomena, a judicious choice of the spectral source call be used as a way to control the type and size of silver nanoparticles formed on PEMs. Depending on the energy of the light source, the Ag nanoparticles present cubic and/or hexagonal crystallographic structures, as confirmed by XRD. Beyond the kinetically controlled process of UV photoinduced cluster formation, the annealing produced by UV light allowed a second mechanism to modify the growth rates, spatial distribution, and phases.

Comparison of the pre-post and transition question assessments in a health education setting

Objective : This study examined the classical pre-intervention/post-intervention assessment (pre–post) and the single post-intervention transition question assessment (transition question) to determine how well these methods reflected qualitative interview–based participant-reported outcomes from chronic disease self-management education programs (CDSMEPs).

Study Design and Setting : A mixed-method qualitative and quantitative approach was applied in 25 interviews with participants recruited from CDSMEPs within Australia. Qualitative interviews with participants were used as a relative “gold standard” and compared with questionnaire-based pre–post and transition question assessments.

Results : Comparison of the two questionnaire-based assessments showed that most of the individual paired responses were discordant (61%). Using participant's qualitative narratives as a “true” indicator, the pre–post assessment was found on more occasions to be discordant with participant-reported outcomes than the transition question. The origin of the inconsistency was largely because of a change in respondents' perspective that had occurred after pretest, which was mediated by CDSMEPs' experiences and insights.

Conclusion : This study suggests that the pre–post assessment has poor validity for the assessment of health education program outcomes. Alternative assessments, such as the transition question, may result in a more accurate reflection of the impact of such programs on participants.

Errors in the identification of question types in investigative interviews of children

This study examined the incidence and nature of the errors made by trainee coders during their coding of question types in interviews in which children disclosed abuse. Three groups of trainees (online, postgraduate and police) studied the coding manual before practising their question coding. After this practice, participants were given two-page field transcripts to code in which children disclosed abuse. Their coding was assessed for accuracy; any errors were analysed thematically. The overall error rate was low, and police participants made the fewest errors. Analysis of the errors revealed four common misunderstandings: (1) the use of a ‘wh’ question always denotes a specific cued-recall question; (2) ‘Tell me’ always constitutes an open-ended question; (3) open-ended questions cannot include specific detail; and (4) specific questions cannot elicit elaborate responses. An analysis of coding accuracy in the one group who were able to practise question coding over time revealed that practice was essential for trainees to maintain their accuracy. Those who did not practise decreased in coding accuracy. This research shows that trainees need more than a coding manual; they must demonstrate their understanding of question codes through practice training tasks. Misunderstandings about questions need to be elicited and corrected so that accurate codes are used in future tasks.