Theoretical study of isolated dangling bonds, dangling bond wires and dangling bond clusters on H:Si(100)-(2×\times1) surface

We theoretically study the electronic band structure of isolated unpaired and paired dangling bonds (DB), DB wires and DB clusters on H:Si(100)-(2$\times$1) surface using Extended H\"uckel Theory (EHT) and report their effect on the Si band gap. An isolated unpaired DB introduces a near-midgap state, whereas a paired DB leads to $\pi$ and $\pi^*$ states, similar to those introduced by an unpassivated asymmetric dimer (AD) Si(100)-(2$\times$1) surface. Such induced states have very small dispersion due to their isolation from the other states, which reside in conduction and valence band. On the other hand, the surface state induced due to an unpaired DB wire in the direction along the dimer row (referred to as $[\bar{1}10]$), has large dispersion due to the strong coupling between the adjacent DBs, being 3.84$\AA$ apart. However, in the direction perpendicular to the dimer row (referred to as [110]), due to the reduced coupling between the DBs being 7.68$\AA$ apart, the dispersion in the surface state is similar to that of an isolated unpaired DB. Apart from this, a paired DB wire in $[\bar{1}10]$ direction introduces $\pi$ and $\pi^*$ states similar to those of an AD surface and a paired DB wire in [110] direction exhibits surface states similar to those of an isolated paired DB, as expected. Besides this, we report the electronic structure of different DB clusters, which exhibit states inside the band gap that can be interpreted as superpositions of states due to unpaired and paired DBs.Comment: 7 pages, 10 figure, 1 tabl

Innovaties in de zorg voor ouderen

In deze 43-ste jaargang van het Tijdschrift voor Gerontologie en Geriatrie opent de redactie de nieuwe rubriek Recent onderzoek. Onderzoekers en programmaleiders van universitaire en niet-universitaire onderzoekscentra op het gebied van de gerontologie en geriatrie in België en Nederland zijn uitgenodigd om samenvattingen in te sturen van onderzoek dat onlangs door hen zelf of in hun vakgroepen of organisaties is afgerond. Met deze rubriek wil de redactie de lezers van het Tijdschrift blijven informeren over onderzoek naar veroudering en de maatschappelijke consequenties daarvan in brede zin: medisch, psychologisch en sociaal.  Het onderzoeksprogramma “Innovaties in de zorg voor ouderen” van de CAPHRI School for Public Health and Primary Care van de Universiteit Maastricht richt zich op drie samenhangende thema’s: (1) onderzoek naar prevalentie en determinanten van relevante zorgproblemen bij ouderen; (2) ontwikkeling en evaluatie van interventies en zorgvernieuwingen die zelfredzaamheid en kwaliteit van leven van ouderen (kunnen) bevorderen en (3) de implementatie van dergelijke interventies en zorgvernieuwingen in de zorgpraktijk. Hieronder volgen enkele voorbeelden van projecten die de afgelopen jaren binnen het programma zijn uitgevoerd

On the Connection of Anisotropic Conductivity to Tip Induced Space Charge Layers in Scanning Tunneling Spectroscopy of p-doped GaAs

The electronic properties of shallow acceptors in p-doped GaAs{110} are investigated with scanning tunneling microscopy at low temperature. Shallow acceptors are known to exhibit distinct triangular contrasts in STM images for certain bias voltages. Spatially resolved I(V)-spectroscopy is performed to identify their energetic origin and behavior. A crucial parameter - the STM tip's work function - is determined experimentally. The voltage dependent potential configuration and band bending situation is derived. Ways to validate the calculations with the experiment are discussed. Differential conductivity maps reveal that the triangular contrasts are only observed with a depletion layer present under the STM tip. The tunnel process leading to the anisotropic contrasts calls for electrons to tunnel through vacuum gap and a finite region in the semiconductor.Comment: 11 pages, 8 figure

Tailoring of the Tell-us Card communication tool for nurses to increase patient participation using Intervention Mapping

Aims and objectives: To describe the tailoring of the Tell-us Card intervention for enhanced patient participation to the Dutch hospital setting using Intervention Mapping as a systematic approach. Background: Even though patient participation is essential in any patient-to-nurse encounter, care plans often fail to take patients' preferences into account. The Tell-us Card intervention seems promising, but needs to be tailored and tested before implementation in a different setting or on large scale. Design: Description of the Intervention Mapping framework to systematically tailor the Tell-us Card intervention to the Dutch hospital setting. Methods: Intervention Mapping consists of: (i) identification of the problem through needs assessment and determination of fit, based on patients and nurses interviews and focus group interviews; (ii) developing a logic model of change and matrices, based on literature and interviews; (iii) selection of theory-based methods and practical applications; (iv) producing programme components and piloting; (v) planning for adoption, implementation and sustainability; and (vi) preparing for programme evaluation. Results: Knowledge, attitude, outcome expectations, self-efficacy and skills were identified as the main determinants influencing the use of the Tell-us Card. Linking identified determinants and performance objectives with behaviour change techniques from the literature resulted in a well-defined and tailored intervention and evaluation plan. Conclusions: The Tell-us Card intervention was adapted to fit the Dutch hospital setting and prepared for evaluation. The Medical Research Council framework was followed, and the Intervention Mapping approach was used to prepare a pilot study to confirm feasibility and relevant outcomes. Relevance to clinical practice: This article shows how Intervention Mapping is applied within the Medical Research Council framework to adapt the Tell-us Card intervention, which could serve as a guide for the tailoring of similar interventions

Density-functional study of hydrogen chemisorption on vicinal Si(001) surfaces

Relaxed atomic geometries and chemisorption energies have been calculated for the dissociative adsorption of molecular hydrogen on vicinal Si(001) surfaces. We employ density-functional theory, together with a pseudopotential for Si, and apply the generalized gradient approximation by Perdew and Wang to the exchange-correlation functional. We find the double-atomic-height rebonded D_B step, which is known to be stable on the clean surface, to remain stable on partially hydrogen-covered surfaces. The H atoms preferentially bind to the Si atoms at the rebonded step edge, with a chemisorption energy difference with respect to the terrace sites of >sim 0.1 eV. A surface with rebonded single atomic height S_A and S_B steps gives very similar results. The interaction between H-Si-Si-H mono-hydride units is shown to be unimportant for the calculation of the step-edge hydrogen-occupation. Our results confirm the interpretation and results of the recent H_2 adsorption experiments on vicinal Si surfaces by Raschke and Hoefer described in the preceding paper.Comment: 13 pages, 8 figures, submitted to Phys. Rev. B. Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

De weg naar een bandenloze zorg in Nederland

Vrijheidsbeperkende maatregelen worden vaak toegepast in de intramurale ouderenzorg. Tegelijkertijd weten we dat de toepassing van restrictieve vrijheidsbeperkende maatregelen zoals banden veel nadelige gevolgen heeft voor bewoners en hun gezondheid schade toe brengt. Toch leidt deze kennis niet tot een vermindering van het aantal maatregelen. Deze bijdrage beschrijft de zoektocht naar een interventie (EXBELT) om banden in verpleeghuizen veilig te verminderen en te voorkomen. EXBELT omvat een instellingsverbod op bandengebruik, een intensief scholingsprogramma, beschikbaarheid van alternatieve interventies en een gespecialiseerde verpleegkundige als consultant. In effectevaluaties blijkt EXBELT zowel op de korte, middellange als lange termijn effectief te zijn. Uit een procesevaluatie komt naar voren dat de interventie grotendeels volgens protocol is uitgevoerd en positief wordt gewaardeerd door medewerkers in verpleeghuizen en familie van bewoners. Tegelijkertijd wordt vastgesteld dat het reduceren van vrijheidsbeperkende maatregelen in Nederland traag verloopt en blijvende aandacht noodzakelijk is om bandengebruik in verpleeghuizen terug te dringen en in de thuiszorg te voorkomen

How stories can contribute towards quality improvement in long-term care

It is important to evaluate how residents, their significant others and professional caregivers experience life in a nursing home in order to improve quality of care based on their needs and wishes. Narratives are a promising method to assess this experienced quality of care as they enable a rich understanding, reflection and learning. In the Netherlands, narratives are becoming a more substantial element within the quality improvement cycle of nursing homes. The added value of using narrative methods is that they provide space to share experiences, identify dilemmas in care provision, and provide rich information for quality improvements. The use of narratives in practice, however, can also be challenging as this requires effective guidance on how to learn from this data, incorporation of the narrative method in the organizational structure, and national recognition that narrative data can also be used for accountability. In this article, five Dutch research institutes reflect on the importance, value and challenges of using narratives in nursing homes.</p