bluuebunny/crossref_metadata_2025 huggingface dataset:
The Semiconductor Industry's Nanoelectronics Research Initiative: Motivation and Challenges
Authors: Welser Jeffrey
Published: May 2008

In recent generations of CMOS technology, exponentially increasing power density due to leakage currents as well as active switching energy is limiting our ability to reap the historical benefits of continued scaling. As the ultimate limits to CMOS scaling are getting closer, completely new approaches in emerging areas in electronics at the nanoscale need to be explored. The Nanoelectronics Research Initiative (NRI) was chartered in 2005 by a consortium of Semiconductor Industry Association (SIA) member companies to develop and administer a university-based program to address this issue. This paper will give an overview of some of the challenges that led to the formation of NRI, and an overview of the kind of research being pursued to extend the cost and performance trends for information technology.
Temperature Profiles During Millisecond Processing
Authors: Camm David M. , Gelpey J.C. , McCoy S , Stuart G. , Kheyrandish H
Published: May 2008

It has been recognized for a long time that both peak temperature and time at temperature are important in RTP processes such as spike anneals. This paper will discuss the importance of time at temperature during flash assist rapid thermal processing (fRTP{trade mark, serif}). Experimentally measured temperature profiles are analyzed assuming simple activation energies to optimize temperature profiles. The relative importance of peak temperature and temperature profile is discussed for electrical activation and diffusion of a 500 eV 1015/cm2 B implant. Considerations of thermal stress produced during processing are included in the optimization process. When all effects are considered, different thermal processes will require tools with very flexible process capabilities. It is shown that both the peak temperatures as well as the temperature profile near the peak are important.
Process Characteristics and Physical Properties of MO-ALD ZrO2 Thin Films Deposited in a 300 mm Deposition System
Authors: Consiglio Steven , Clark Robert D. , Wajda Cory S. , Igeta Masanobu , Leusink Gert J. , Sugawara Takuya , Nakabayashi Hajime
Published: May 2008

This work presents a detailed investigation of the deposition of ZrO2 using a metallorganic precursor in a 300 mm wafer processing ALD system. The ZrO2 films in this study were characterized by inline spectroscopic ellipsometry and corona-oxide-semiconductor measurements, and offline Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). A growth temperature window between 215 {degree sign}C and 340 {degree sign}C was investigated and the thermal CVD rate was observed to increase above 265 {degree sign}C, thus representing an upper temperature boundary for ALD-dominated growth. For a saturated process at 265 {degree sign}C, a within-wafer non-uniformity of < 2 % for films deposited using 8 cycles or greater was obtained. An in-situ capping with TiN followed by an in-situ post-deposition rapid thermal anneal was also performed in order to assess the thermal stability of the deposited gate stack. For rapid thermal annealed films ({greater than or equal to} 900 {degree sign}C) with a TiN cap, no significant thermally-induced chemical changes were observed while a peak in the XRD spectra attributable to tetragonal and/or cubic phase ZrO2 was observed. Excellent film conformality and coverage over a FinFET structure was observed by TEM.
High-k/Metal Gates- From Research Lab to Market Reality
Authors: Narayanan Vijay
Published: May 2008

High-k/Metal Gate stacks have long held the promise to replace SiON/Poly-Si stacks in conventional CMOS devices. In this paper it will be shown that substantial materials innovations by scientists and engineers working concurrently within IBM Alliances in Research and Development over the past decade have helped understand and circumvent fundamental high-k based obstacles including reduced electron mobility, oxygen based thermal instabilities (interfacial regrowth & oxygen vacancies) thereby paving the way for High-k/Metal Gate CMOS implementation in a gate first approach.
Atomic-Layer-Deposition of SiO2 with Tris(Dimethylamino)Silane (TDMAS) and Ozone Investigated by Infrared Absorption Spectroscopy
Authors: Hirose Fumihiko , Kinoshita Yuta , Shibuya Suguru , Miya Hironobu , Hirahara Kazuhiro , Kimura Yasuo , Niwano Michio
Published: May 2008

We have studied SiO2 ALD processes with precursors of tris(dimethylamino)silane (TDMAS) and ozone on Si(100) surfaces at room temperature by infrared absorption spectroscopy with a multiple internal reflection geometry. It was found that TDMAS dissociatively adsorbs on OH sites of hydroxyrated Si surfaces and ozone irradiation is effective to remove the hydroaminocarbon adsorbates introduced in the course of the TDMAS adsorption. Compensation of OH sites by a water vapor treatment after the ozone process is effective to sustain the cyclic SiO2 deposition.
Effect of Thermal Annealing on the Electrical Properties of Thin ZrO2 Layers
Authors: Sanchez Lorenzo A. , Nedev Nicola , Zlatev Roumen K. , Valdez Benjamin S. , Alvarez Lydia
Published: May 2008

The electrical properties of Al/ZrO2/SiO2/Si Metal-Insulator-Semiconductor (MIS) structures with ZrO2 layer fabricated by radio frequency sputtering followed by thermal annealing at 600 ºC or 850 ºC in O2 are studied. The high frequency C-V curves of all MIS structures demonstrate counter clockwise hysteresis due to charging from the top electrode. The samples annealed at 850 ºC have larger hysteresis window, probably due to formation of polycrystalline structure. At negative voltage Poole-Frenkel emission is the dominant transport mechanism through the ZrO2/SiO2 dielectric, while at positive voltage up to current density of ~3x10-8 A/cm2 the current limiting mechanism is Fowler-Nordheim tunneling in the SiO2 conduction band. At higher current density again Poole-Frenkel emission is the dominant transport mechanism.
Performance of Germanium Metal-Insulator-Semiconductor Field Effect Transistors with Nickel Germanide Source/Drain
Authors: Taoka Noriyuki , Ikeda Keiji , Yamamoto Toyoji , Yamashita Yoshimi , Harada Masatomi , Suzuki Kunihiro , Kiso Osamu , Sugiyama Naoharu , Takagi Shin-ichi
Published: May 2008

We have fabricated NiGe/Ge diodes and Ge pMISFETs with the NiGe S/D, and studied the electrical characteristics in detail. The NiGe/n-Ge Schottcky S/D is shown to be suitable for Ge pMISFETs. The high performance Ge pMISFETs with sub-100nm gate length has been demonstrated. The dependencies of the inversion layer hole mobility of Ge on the impurity concentration and temperature, and the characteristics of short channel pMISFETs were experimentally examined.
Crystallographic Silicon-Etching for Ultra-High Aspect-Ratio FinFET
Authors: Jovanovic Vladimir , Suligoj Tomislav , Nanver Lis
Published: May 2008

The fabrication process for the FinFET with ultra-high fin-height to fin-width aspect-ratio is presented. The processing is based on the crystallographic etching of (110) bulk silicon-wafers by TMAH to expose the vertical (111) planes. The nitride-spacers are used as the hard-mask for the fin-etching and the fins are isolated by the planarization and etch-back of the thick isolation oxide. The demonstration devices exhibit nearly ideal S of 62-64 mV/dec and DIBL of 10 mV/V or lower, for the gate-length of 410 nm and the height of the active part of the fin of 400 nm. The output current is limited by the large series resistances for both pFETs and nFETs, and additionally by the gate-depletion in nFETs, but large currents per fin, above 30 μA for pFET are achieved due to tall fin-structure.
Application Of HCl Gas Phase Etch In The Production Of Novel Devices
Authors: Hikavyy Andriy Y. , Rooyackers Rita , Verheyen Peter , Leys Frederik , Vellianitis Georgios , Van Dal Mark J. , Lander Rob , Loo Roger
Published: May 2008

Multigate MOSFET and epi-tip transistors are promising device concepts which are currently actively investigated. Being attractive from the performance point of view they present certain technological challenges. One of them is the difficulty to control poly-gate encapsulation during the HF removal of native SiO2 prior to the epitaxial Si deposition of raised sourse/drains. Failed poly-Si encapsulation results in the growth of poly-Si during selective epitaxial growth (SEG) of Si, which shortcuts the source/drain areas. Further it might lead to shadowing effects during post epi implantation steps. These issues can be solved by HCl gas phase etch which effectively removes poly-Si with minimal Source/Drain removal. In this paper, we first discuss the HCl gas phase etch selectivity between poly-Si and crystalline Si (c-Si) in the temperature range of 575 - 8500C as measured on blanket wafers. Further, we show how this selectivity can be implemented in the production scheme of FinFET devices and epi-tip transistors and as a surface preparation for the epi deposition. Difficulties which can arise due to the HCl gas phase etch are also presented and discussed.
Characterization of Process Induced Surface Profiles and Lattice Strains using Optical Surface Profilometry and Multi-wavelength Raman Spectroscopy
Authors: Yoo Woo Sik , Ueda Takeshi , Kajiwara Junya , Ishigaki Toshikazu , Kang Kitaek
Published: May 2008

In-line process monitoring plays a vital role in quickly identifying and resolving yield problems in semiconductor manufacturing environments. It is also a very important and powerful methodology in the understanding of material properties during process development and accelerating yield ramps in smaller scale devices. We have developed non-destructive, in-line process and/or material property monitoring methods which use reflection, diffraction and scattering of laser beams. Process induced changes of surface profiles and lattice strains are characterized using newly developed optical surface profilometry (OSP) and multi-wavelength Raman spectroscopy (MRS) systems. Optical surface profiles and Raman characterization were performed on Ni films on 300mm p--Si wafers with or without TiN capping layers, before and after annealing in addition to the conventional sheet resistance measurement using a four point probe. Significant changes in wafer surface profiles and strains near the Ni/Si interface were observed near phase transition (Ni/Si→Ni2Si→NiSi→ NiSi2) temperatures as determined by the temperature sensitivity curve of sheet resistance.
High-Quality Nickel Silicide MOS Capacitors Fabricated with a Cl Plasma Containing NiCl
Authors: Hirose Fumihiko , Kanomata Kensaku , Suzuki Takahiko , Oyama Naoki
Published: May 2008

We have successfully fabricated nickelsilicide-metalgate MOS capacitors at a low temperature of 280åC by treating poly Si stacked SiO2/Si substrates with a Cl plasma containing NiCl. We have confirmed atomically sharp NiSi/oxide interfaces after the present process where any interface segregation can not be observed by cross-sectional TEM measurements. The present process allows a control of Ni concentration in the gate metal film and the work function in the gate metal is adjustable in the range from 4.3 to 4.9 eV, which is suitable for the Si CMOS process.
High Growth Rate SiO2 by Atomic Layer Deposition
Authors: Matero Raija , Haukka Suvi , Tuominen Marko
Published: May 2008

A remarkably high growth rate of more than 1 Aå/cycle was obtained when using a new aminosilane precursor AHEAD{trade mark, serif} for atomic layer deposition of SiO2 thin films. The films were deposited at 150 - 300 {degree sign}C on 200 mm wafers. AHEAD{trade mark, serif} is a low vapour pressure liquid which was vaporised at 110 {degree sign}C. Ozone was used as the oxidizer.
Local Corrosion by Film Stress and Solution Temperature during CMP
Authors: Kang Min Cheol , Kim Yung Jun , Kim Jae Jeong
Published: May 2008

In this work, the synergy effects of the stress generation and temperature rise of slurry on the local corrosion during Cu CMP. We observed that the magnitude of generated stress was proportionate to the formation rate of Cu oxide. When specific additive was added into H2O2 solution, re-crystallization, which occurred to minimize the generated stress on the film, caused the breakdown of Cu oxide. The increase in Cu etch rate was resulted from an increased slurry temperature. Therefore, severe local corrosion, particularly at the recess area, occurred through the breakdown of Cu oxide and the temperature rise of slurry.
Effect of Alkaline Agent with Organic Additive in Colloidal Silica Slurry on Polishing Rate Selectivity of Polysilicon-to-SiO2 in Polysilicon CMP
Authors: Hwang Hee-Sub , Kang Hyun-Goo , Park Jin-Hyung , Paik Ungyu , Park Hyung-Soon , Park Jea-Gun
Published: May 2008

We have studied the effects of varying the size and the concentration of the abrasive in colloidal silica slurry and the concentration of different alkaline agent with organic polymer were investigated. We found that the surface roughness of the polysilicon film with TMAH was better than other alkaline agent. In addition, with increasing TMAH concentration, the polishing rate of polysilicon and the polysilicon-to-oxide polishing rate selectivity were reduced after an initial increase. And the organic polymer suppresses the polishing rate of the oxide film. We explained the reason by difference of hydrophobicity between polysilicon and oxide film with addition of alkaline agent and PAM in order to elucidate the mechanism of increase in polysilicon-to-oxide polishing rate selectivity.
STI Post CMP Cleaning Solution Development
Authors: Tamboli Dnyanesh , Banerjee Gautam , Subramanian Paramasivan , Rao Madhukar B.
Published: May 2008

Shallow Trench Isolation (STI) is the standard isolation method for fabrication of submicron CMOS devices. Ceria based slurries are often used for the chemical mechanical planarization (CMP) of STI structures. It is essential therefore, to clean the structure after the CMP process to remove the ceria and other organic residues, usually resulting from the slurry. In this paper, post CMP cleaning of STI wafers with a specially formulated clean solution has been discussed.
Improved InGaN LED Efficiency using Photonic Crystal Patterning and Surface Plasmon Enhanced Emission
Authors: Fischer Arthur , Subramania Ganesh , Lee Yun-Ju , Luk Ting , Wendt Joel , Koleske Daniel
Published: May 2008

Surface plasmon mediated emission can improve the efficiency of light emitting diodes (LEDs) by coupling excited carriers to surface plasmon modes. By combining surface plasmon effects with photonic crystal patterning it is possible to enhance the internal quantum efficiency as well as the light extraction efficiency of blue and green InGaN LEDs. Time-resolved and time-integrated photoluminescence measurements are used to show that surface plasmons can enhance the radiative decay rate as well as the overall total luminescence for a properly designed sample. Our design for a practical, electrically injected InGaN surface plasmon LED will be presented.
AlGaN/GaN HEMT And ZnO Nanorod Based Sensors for Chemical and Bio-Applications
Authors: Kang B. S. , Wang Hung-Ta , Ren F. , Chancellor T. J. , Lele T. P. , Tseng Y. , Pearton Stephen J. , Morey T. E. , Dennis D. M. , Johnson J. W. , Rajagopal P. , Roberts J. C. , Piner E. L. , Linthicum K. J. , Dabiran A. , Osinsky A. , Chow P. P.
Published: May 2008

AlGaN/ GaN High Electron Mobility Transistors (HEMTS) were used to detect pH value and glucose concentration in the exhaled breath condensate (EBC). A Peltier element mounted on the backside of the AlGaN/GaN HEMT was used to lower the temperature of the sensor in order to condense the exhaled breath. The measured current change of the HEMT shows that the pH of the condensate from the exhaled breath is within the range of 7- 8, corresponding to the range of interest for human blood. The sensor exhibited a repeatable change of 1.24 mA/mm of the drain current at a drain bias of 0.25V, when the surface was exposed to repeated exhalations. ZnO nanorod-gated AlGaN/GaN HEMTs were used to detect glucose in EBC. A ZnO nanorod array was selectively grown on the gate area using low temperature hydrothermal decomposition to immobilize glucose oxidase (GOx).
InAs Quantum Well Transistors for High-Speed Low Power Applications
Authors: Chang Edward Yi , Kuo Chien I , Hsu Heng Tung
Published: May 2008

An Indium Arsenic based quantum well field-effect transistors (QWFETs) with 80 nm gate length have been fabricated and evaluated for high speed and low DC power applications. The device exhibits high drain current density (1015 mA/mm), high transconductance (1920 mS/mm) and excellent RF performance (fT = 393 GHz), current gain cutoff frequency (fT), at an operating supply voltage of only 0.5 V. As for the gate delay time, the device shows a very low value of 0.54 psec at the VCC of 0.5 V. The InAs transistors demonstrate higher fT than silicon NMOS transistors while consuming smaller active power, indicating its great potential in next generation low power logic applications.
Novel Copper-Zinc Oxide Arrayed Nanoatalysts for Hydrogen Production Applications
Authors: Lin Yan-Gu , Hsu Yu-Kuei , Chen San-Yuan , Chen L.-C. , Chen Kuei-Hsien
Published: May 2008

We report a simple and effective wet chemical technique for facile synthesis of large-scale and arrayed copper-zinc oxide nanostructures in regard to high performance of hydrogen production. The zinc oxide arrays as support were grown by a template-free aqueous route and subsequently the copper catalysts were impregnated on zinc oxide surface at low temperature by means of spontaneous reduction to form the hierarchical core-shell type nanostructures. Systematic analyses were employed to examine morphological, component, and structural characterizations of arrayed copper-zinc oxide nanostructures. In particular, these nanocomposites exhibited high methanol conversion, hydrogen production, and carbon dioxide selectivity at lower reaction temperature in comparison with the conventional catalysts. As shown above, our work here could open up new possibilities for the preparation of core-shell type copper-zinc oxide nanocomposites in micro reformed hydrogen fuel cell (μRHFC) devices applications.
Structure and Optical Properties of ZnO/NiSi/Si System
Authors: Ren Wei , Gong Hao , Chi Dongzhi
Published: May 2008

High quality ZnO films grown on NiSi/Si as well as chemically cleaned Si substrates were investigated. It was found that better light emission properties were obtained in ZnO/NiSi/Si system than in ZnO/Si counterpart . A filter effect of NiSi was notably found, which could greatly improve the signal-to-noise ratio of the ZnO film during Raman measurement.
Self-Organized and High Aspect Ratio Nanoporous Zinc Oxide Prepared by Anodization
Authors: Ono Sachiko , Kobayashi Yuta , Asoh Hidetaka
Published: May 2008

We have fabricated self-organized nanoporous zinc oxide having an extremely high aspect ratio by a simple, high throughput and non-costly wet electrochemical process without use of catalyst: anodization of zinc plate in aqueous solutions. By optimizing the anodizing condition, we could obtain a film with the thickness more than 90 mm. BET specific surface area of the anodic porous ZnO was approximately 28.5 m2/g. XRD measurement of the anodic ZnO reveals diffraction spectra of polycrystalline ZnO. From UV and visible light optical absorption spectra of thick anodic ZnO films, the absorption edge and the estimated band gap were 370 nm and 3.35 eV respectively. Photo catalytic activity of the anodic ZnO was ascertained by a methylene blue degradation test under UV irradiation at the wavelength of 365 nm. The proposed process with use of anodization of zinc could be expanded to other metals to obtain various oxides semiconductors, and has potential technological applications in the fields of catalysis, supports, and sensors.
Characteristics of CdO Films Deposited by the Sol Gel Technique
Authors: Murali K. R. , Sathyamurthy Krishna , Kathiravan J. , Manjunathan U. , Senthil Senthil
Published: May 2008

Transparent conducting oxide films of cadmium oxide were deposited by the sol gel dip coating technique using acrylamide route. The precursors were AR grade cadmium chloride, acrylamide, N,N,bis methylene acrylamide, ammonium persulphate. Cleaned glass substrates were dipped in the and withdrawn slowly. The films were post annealed at different temperatures in the range of 200 - 450 C in air. The films were characterized by x-ray diffraction studies which indicated cubic CdO. Lattice parameter, strain, dislocation density, texture coefficient etc were calculated from the x-ray data. Optical absorption measurements indicated a direct band gap of 2.45 eV. 80 % Transmission was obtained. EDAX spectrum indicated the formation of CdO.
Models of Change and the Adoption of Web Technologies
Authors: Nielsen Jørn Flohr
Published: May 2008

This article illustrates how advanced theories of change are useful in understanding the actual adoption of emergent Internet technologies drawing on surveys of Nordic banks. The point of departure is Van de Ven and Poole's identification of four basic types of theories of change: life cycle, teleological (including planned change), dialectical, and evolutionary theories. These theories are shown to provide a useful framework for examining the adoption and implementation of Internet technology at different stages. Especially, it is shown how participation can be included in the models and how it connects the change motors. The analysis questions the assumption that participation always helps in overcoming resistance to change. Participation often leads to tensions and conflicts, especially when multiple motors and different change efforts are operating simultaneously. Practically, this application of change models can help in the guidance of planned change by enriching traditional diagnostic models.
Regional Phonetic Differentiation in Standard Canadian English
Authors: Boberg Charles
Published: May 2008

Taking as a point of departure the preliminary view of regional phonetic differentiation in Canadian English developed by the Atlas of North American English, this article presents data from a new acoustic-phonetic study of regional variation in Canadian English carried out by the author at McGill University. While the Atlas analyzes mostly spontaneous speech data from thirty-three speakers covering a broad social range, the present study analyzes word list data from a larger number of speakers (eighty-six) drawn from a narrower social range, comprising young, university-educated speakers of Standard Canadian English from all across the country. The new data set permits a more detailed view of regional variation within Canada than was possible in the Atlas, which focuses on differentiating Canadian from neighboring varieties of American English. This view adds detail to the established account in some respects, while suggesting a revised regional taxonomy of Canadian English in others. In particular, this article reports on several phonetic isoglosses that divide Canada's Prairie region from Ontario, thereby splitting the “Inland Canada” region of the Atlas into western and eastern halves. In fact, the data presented here suggest a division of Standard Canadian English into six regions at the phonetic level, rather than the three proposed by the Atlas: British Columbia, the Prairies, Ontario, Quebec (Montreal), the Maritimes, and Newfoundland. This taxonomy corresponds to the six major regions identified in the study of lexical data reported in Boberg (2005b).
Intermittent Hemodialysis Versus Continuous Renal Replacement Therapy for Acute Renal Failure in the Intensive Care Unit: An Observational Outcomes Analysis
Authors: Abdul Rauf Anis , Hall Long Kirsten , Gajic Ognjen , Anderson Stephanie S. , Swaminathan Lalithapriya , Albright Robert C.
Published: May 2008

Background: Studies have failed to show a survival difference between intermittent hemodialysis (IHD) and continuous renal replacement therapy (CRRT). Comparative cost analyses are limited and fail to control for differences in patient disease severity and comorbid conditions. The authors retrospectively estimated clinical and economic outcomes associated with CRRT and IHD among critically ill patients experiencing acute renal failure (ARF) in 2 tertiary care hospitals in Rochester, Minnesota, between January 1, 2000, and December 12, 2001. Methods: 161 critically ill patients requiring dialysis for ARF were analyzed. Patient demo-graphics, comorbid conditions, ARF etiology, mode of renal replacement therapy (RRT), renal recovery, and survival were abstracted from medical chart. APACHE II scores at dialysis initiation were calculated. Administrative data tracked length of stay (LOS) and direct medical costs from initiation of RRT to death or intensive care unit (ICU) and hospital discharge. Multivariate modeling was used to adjust outcomes for baseline differences. Results: 84 (52%) of the patients received CRRT and 77 (48%) received IHD. CRRT-treated patients were younger (58 vs 65 years), less likely male (58% vs 77%), had higher APACHE II scores (32 vs 27) with a higher incidence of sepsis (46% vs 30%) and respiratory disease (56% vs 39%), and were less likely to have chronic renal insufficiency (32% vs 49%). With adjustment for differences in baseline patient characteristics, the RRT method did not affect the likelihood of renal recovery, in-hospital survival, or survival during follow-up. Mean adjusted ICU LOS was 9.5 days shorter for IHD-treated than CRRT-treated patients ( P < .001), and the adjusted mean difference in hospital and total costs associated with ICU stay was $56 564 and $60 827, in favor of IHD ( P < .001). Mean adjusted total costs through hospital discharge were $93 611 and $140 733 among IHD-treated and CRRT-treated patients, respectively ( P < .001). Conclusions: This observational study suggests that costs may significantly differ by mode of RRT despite similar severity-adjusted patient outcomes. Future prospective comparisons of renal replacement modalities will need to include both clinical and economic outcomes.
Self-reports on the IQCODE in Older Adults: A Psychometric Evaluation
Authors: Jansen Aaltje P. D. , van Hout Hein P. J. , Nijpels Giel , van Marwijk Harm W. J. , Gundy Chad , de Vet Henrica C. W. , Stalman Wim A. B.
Published: May 2008

The Informant Questionnaire on Cognitive Decline (IQCODE) has been successful in identifying demented persons in a general population. In this study, this questionnaire was used as a self-report screening for dementia symptoms. The object was to investigate the feasibility, homogeneity, and construct validity of self-reports on the IQCODE. Participants were 4823 community-dwelling older adults who received an IQCODE-SR. Feasibility was assessed on the basis of response rate, the proportion of missing data for each item, and the number of persons who received help in completing the questionnaire. Homogeneity was checked with Cronbach's α. To investigate construct validity, hypotheses on performance of the IQCODE-SR were tested. Feasibility was acceptable, with a response rate of 58.9%. Missing answers per item ranged from 2.5% to 7.3%, and 915 of 2841 participants received help in completing the questionnaire. Homogeneity was good, with Cronbach's α = .94. The majority of hypotheses on construct validity were confirmed. It was concluded that the IQCODE-SR meets the basic requirements of a good measurement instrument.
Major Depression and Disability in Older Primary Care Patients With Heart Failure
Authors: Friedman Bruce , Lyness Jeffrey M. , Delavan Rachel L. , Chunyu Li  , Barker William H.
Published: May 2008

The purpose of this study was to examine the association between dependence in activities of daily living (ADL) and instrumental ADL (IADL) and major depression among 415 community-dwelling primary care patients age 65+ with heart failure and significant ADL or IADL dependence. Main findings include (1) a progressive increase in depression prevalence from 0% for no IADL dependence to about 40% for 6 IADL dependencies ( P < .001), (2) a steady rise in depression prevalence to 40% for 6 ADL dependencies following a “floor effect” at about 10% for 0 to 2 ADL dependencies ( P < .001), and (3) the association in a logistic regression model of major depression with number of IADL dependencies ( P = .016) but not with number of ADL dependencies ( P = .602). Our principal conclusion is that the progressively greater likelihood of major depression as the number of IADL dependencies increases has important clinical, personal, social, and public health relevance.
Brief Screening for Mild Cognitive Impairment in Elderly Outpatient Clinic: Validation of the Korean Version of the Montreal Cognitive Assessment
Authors: Lee Jun-Young , Dong Woo Lee  , Cho Seong-Jin , Na Duk L. , Hong Jin Jeon  , Kim Shin-Kyum , You Ra Lee  , Youn Jung-Hae , Kwon Miseon , Lee Jae-Hong , Maeng Je Cho
Published: May 2008

The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening tool with high sensitivity for screening patients with mild cognitive impairment (MCI). The authors examined the validity and reliability of the Korean version of the MoCA (MoCA-K) in elderly outpatients. The MoCA-K, a Korean version of the Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR) scale, and neuropsychological batteries were administered to 196 elderly persons (mild Alzheimer's disease [AD] = 44, MCI = 37, normal controls [NC] = 115). MoCA-K scores were highly correlated with those of MMSE and CDR. Using a cutoff score of 22/23, the MoCA-K had an excellent sensitivity of 89% and a good specificity of 84% for screening MCI. Internal consistency and test−retest reliability were good. The results obtained show that the MoCA-K is brief, reliable, and suitable for use as a screening tool to screen MCI patients in elderly outpatient clinic settings.
Can a Community Policing Initiative Reduce Serious Crime?
Authors: Connell Nadine M. , Miggans Kristen , McGloin Jean Marie
Published: May 2008

Because of the broad conception of community policing, there is extensive variation in strategies across agencies. Consequently, extant evaluations of community policing programs and techniques are limited, both in terms of their conclusions and generalizability. In addition, previous studies have primarily focused on large metropolitan police departments that have been given several types of resources to implement community policing models. This is not, however, reflective of most police departments. The current evaluation assesses community policing as an officer-initiated program in a suburban police department. Officers involved with the design and implementation of this community policing model were interviewed and crime data for the initiative location and two comparable police beats were collected over an 8-year period. Time series analyses indicated a significant reduction in violent and property crimes in the targeted area, but not in comparable areas in the county.
Reduction Reaction to Thiol Group of Dithiobenzoate End Group in Polystyrene Polymerized by Reversible Addition–Fragmentation Chain Transfer
Authors: Nishi Hiroyasu , Kobatake Seiya
Published: May 2008

A dithiobenzoate end group of polystyrene generated by reversible addition–fragmentation chain-transfer radical polymerization was reduced to a thiol group in various reduction methods, and the structure of the products was analyzed using 1H NMR, IR, and MALDI-TOFMS. It was found that the side reactions including a dimerization of the polymers were observed and they can be prevented by a specific process.
Asymmetric Hetero Diels–Alder Reaction Catalyzed by Chromium Complexes of Heterogeneously Hybridized Salen/Salan Ligands
Authors: Eno Satomi , Egami Hiromichi , Uchida Tatsuya , Katsuki Tsutomu
Published: May 2008

Various heterogeneously or homogeneously hybridized salen/salan ligands were synthesized, and study of hetero Diels–Alder reactions using their chromium complexes as catalysts revealed that a well-designed heterogeneously hybridized ligand serves as a chiral auxiliary as efficiently as the homogeneously hybridized ligand and its chromium complex has high catalytic activity.
The Impact of CEO Status Diffusion on the Economic Outcomes of Other Senior Managers
Authors: Graffin Scott D. , Wade James B. , Porac Joseph F. , McNamee Robert C.
Published: May 2008

In this paper we develop and test predictions regarding the impact of CEO status on the economic outcomes of top management team members. Using a unique data set incorporating Financial World's widely publicized CEO of the Year contest, we found that non-CEO top management team members received higher pay when they worked for a high-status CEO. However, star CEOs themselves retained most of the compensation benefits. We also show that there is a “burden of celebrity” in that the above relationships were contingent on how well a firm performs. Last, we found that, when compared with the subordinates of less-celebrated CEOs, members of top management teams who worked for star CEOs were more likely to become CEOs themselves through internal or external promotions.
Excavating Chansonniers: Musical Archaeology and the Search for Popular Song
Authors: ALDEN JANE
Published: May 2008

What constitutes popular song? This seems an unlikely question to raise in connection with chansonniers copied in the Loire Valley during the later decades of the fifteenth century. But in fact it was a special preoccupation with France's popular musical heritage that led to the discovery in the nineteenth century of the largest two such manuscripts—the Laborde and Dijon Chansonniers. A government-sponsored search for materials emblematic of national identity was directly responsible, in 1857, for bringing the Laborde Chansonnier to light. Although this manuscript was deemed “unable to qualify for the distinction of popularity,” when the Dijon Chansonnier emerged—at approximately the same time—there was a scholarly consensus regarding its popular contents.

Since ancient popular songs were believed to represent the indigenous heritage of the French people, the “Frenchness” of the songs unearthed was of paramount importance. But as many of the composers found in the Loire Valley chansonniers were born in areas under Burgundian control, their Frenchness was not self-evident.

The earliest explorations of the formes fixes chanson repertory were made as part of the search for the true songs of the people. Later scholars rejected the idea that polyphonic art songs, composed by known individuals, could be part of a popular song tradition. But in focusing on the composers in these manuscripts, rather than the artifacts themselves, they divorced this repertory from its historical context. In the 1920s, a group of scholars working in Paris offered a broader approach, one that considered the manuscripts as art objects in their own right. The pioneering work of these scholars suggested a type of inquiry that remains relevant today.
Investigation of equal and opposing flow junctions
Authors: Frizzell C. S. , Khan A. A. , Werth D.
Published: May 2008

This paper presents an experimental study of a 90° channel junction with equal and opposing flow in the upstream main channel. The aim of the study is to predict the size of the recirculation zones in the downstream branch channel that are formed as the flow makes a 90° turn after colliding and the associated energy loss. Detailed three-dimensional velocity profiles are measured with an acoustic Doppler velocimeter in the upstream main channel and downstream branch channel for different width ratios of the main and branch channels and inlet Froude numbers. The velocity profiles are depth-averaged to determine the maximum width of the recirculation zones in the branch channel. The velocity and flow depth distributions in the main and branch channels near and within junctions are dependent on inlet Froude number and channel width ratio. An analytical model based on mass, momentum and energy principles is developed and used to predict the maximum width of the recirculation zones. The maximum relative error in the predicted maximum width of the separation zone is less than 6·5%.
Assessment of existing soakaways for reuse
Authors: Chen H.-P. , Stevenson M. W. , Li C.-Q.
Published: May 2008

This paper describes a practical approach for the investigation, assessment and design of existing soakaways. This method can be utilised for measuring the performance and capacity of the systems and examining whether the systems are suitable for reuse when information about the design and installation of the systems is not available. The requirements for field observations and the procedure for a soil infiltration test for the installed system are suggested for successful assessment. The soil infiltration rate of the system is estimated from the field test data without requiring information on the design and construction details of the system. The system's working condition is measured by a performance indicator related to the time taken to empty the soakaway. This is then employed to evaluate the potential reuse of the system. The system's drain capacity is determined by the design principles of current practice and the effect of climate change on its drain capacity is considered. Contamination of soils around the systems after long-term use of discharge service and the water present in soakaway chambers are also investigated. A detailed case study for the reuse of four installed soakaways for a new housing development demonstrates how the proposed approach provides a straightforward process for the infiltration performance and drain capacity assessment of the existing systems. The effectiveness and applicability of the proposed approach are further demonstrated from the assessments for a number of installed systems over various sites.
A methodology for regional-scale flood risk assessment
Authors: Gouldby B. , Sayers P. , Mulet-Marti J. , Hassan M. A. A. M. , Benwell D.
Published: May 2008

Sound flood risk management decision making is underpinned by flood risk analysis. Current methods applied at regional and local scales are often limited in their consideration of the potential for defences to fail. Ultimately this can lead to underestimates of the true risk and subsequent difficulties in justifying mitigation measures such as maintenance and replacement of defences. A methodology has been developed for assessing flood risk arising from fluvial and coastal sources that explicitly considers defence failures represented through fragility curves. This method requires consideration of flooding scenarios involving multiple defence section failures and flood events ranging in severity. It has therefore been necessary to develop a purpose-specific flood spreading method that is capable of simulating many flood events in practical timescales. The method has been applied to the Thames Estuary, where outputs including spatial maps of flood risk and defences attributed with residual risk have been used to support decisions relating to strategic flood risk management over the coming century.
DO RESOURCES OR NATURAL ENEMIES DRIVE BEE POPULATION DYNAMICS IN FRAGMENTED HABITATS
Authors: Steffan-Dewenter Ingolf , Schiele Susanne
Published: May 2008

The relative importance of bottom‐up or top‐down forces has been mainly studied for herbivores but rarely for pollinators. Habitat fragmentation might change driving forces of population dynamics by reducing the area of resource‐providing habitats, disrupting habitat connectivity, and affecting natural enemies more than their host species. We studied spatial and temporal population dynamics of the solitary bee Osmia rufa (Hymenoptera: Megachilidae) in 30 fragmented orchard meadows ranging in size from 0.08 to 5.8 ha in an agricultural landscape in central Germany. From 1998 to 2003, we monitored local bee population size, rate of parasitism, and rate of larval and pupal mortality in reed trap nests as an accessible and standardized nesting resource. Experimentally enhanced nest site availability resulted in a steady increase of mean local population size from 80 to 2740 brood cells between 1998 and 2002. Population size and species richness of natural enemies increased with habitat area, whereas rate of parasitism and mortality only varied among years. Inverse density‐dependent parasitism in three study years with highest population size suggests rather destabilizing instead of regulating effects of top‐down forces. Accordingly, an analysis of independent time series showed on average a negative impact of population size on population growth rates but provides no support for top‐down regulation by natural enemies. We conclude that population dynamics of O. rufa are mainly driven by bottom‐up forces, primarily nest site availability.
BOTTOM‐UP AND CLIMATIC FORCING ON THE WORLDWIDE POPULATION OF LEATHERBACK TURTLES
Authors: Saba Vincent S. , Spotila James R. , Chavez Francisco P. , Musick John A.
Published: May 2008

Nesting populations of leatherback turtles (Dermochelys coriacea) in the Atlantic and western Indian Oceans are increasing or stable while those in the Pacific are declining. It has been suggested that leatherbacks in the eastern Pacific may be resource limited due to environmental variability derived from the El Niño Southern Oscillation (ENSO), but this has yet to be tested. Here we explored bottom‐up forcing and the responding reproductive output of nesting leatherbacks worldwide. We achieved this through an extensive review of leatherback nesting and migration data and by analyzing the spatial, temporal, and quantitative nature of resources as indicated by net primary production at post‐nesting female migration and foraging areas. Leatherbacks in the eastern Pacific were the smallest in body size and had the lowest reproductive output due to less productive and inconsistent resources within their migration and foraging areas. This derived from natural interannual and multidecadal climate variability together with an influence of anthropogenic climate warming that is possibly affecting these natural cycles. The reproductive output of leatherbacks in the Atlantic and western Indian Oceans was nearly twice that of turtles in the eastern Pacific. The inconsistent nature of the Pacific Ocean may also render western Pacific leatherbacks susceptible to a more variable reproductive output; however, it appears that egg harvesting on nesting beaches is their major threat. We suggest that the eastern Pacific leatherback population is more sensitive to anthropogenic mortality due to recruitment rates that are lower and more variable, thus accounting for much of the population differences compared to Atlantic and western Indian turtles.
HABITAT QUALITY AND HETEROGENEITY INFLUENCE DISTRIBUTION AND BEHAVIOR IN AFRICAN BUFFALO (SYNCERUS CAFFER)
Authors: Winnie John A. , Cross Paul , Getz Wayne
Published: May 2008

Top‐down effects of predators on prey behavior and population dynamics have been extensively studied. However, some populations of very large herbivores appear to be regulated primarily from the bottom up. Given the importance of food resources to these large herbivores, it is reasonable to expect that forage heterogeneity (variation in quality and quantity) affects individual and group behaviors as well as distribution on the landscape. Forage heterogeneity is often strongly driven by underlying soils, so substrate characteristics may indirectly drive herbivore behavior and distribution. Forage heterogeneity may further interact with predation risk to influence prey behavior and distribution. Here we examine differences in spatial distribution, home range size, and grouping behaviors of African buffalo as they relate to geologic substrate (granite and basalt) and variation in food quality and quantity. In this study, we use satellite imagery, forage quantity data, and three years of radio‐tracking data to assess how forage quality, quantity, and heterogeneity affect the distribution and individual and herd behavior of African buffalo. We found that buffalo in an overall poorer foraging environment keyed‐in on exceptionally high‐quality areas, whereas those foraging in a more uniform, higher‐quality area used areas of below‐average quality. Buffalo foraging in the poorer‐quality environment had smaller home range sizes, were in smaller groups, and tended to be farther from water sources than those foraging in the higher‐quality environment. These differences may be due to buffalo creating or maintaining nutrient hotspots (small, high‐quality foraging areas) in otherwise low‐quality foraging areas, and the location of these hotspots may in part be determined by patterns of predation risk.
BLACK YEAST SYMBIONTS COMPROMISE THE EFFICIENCY OF ANTIBIOTIC DEFENSES IN FUNGUS‐GROWING ANTS
Authors: Little Ainslie E. F. , Currie Cameron R.
Published: May 2008

Multiplayer symbioses are common in nature, but our understanding of the ecological dynamics occurring in complex symbioses is limited. The tripartite mutualism between fungus‐growing ants, their fungal cultivars, and antibiotic‐producing bacteria exemplifies symbiotic complexity. Here we reveal how black yeasts, newly described symbionts of the ant–microbe system, compromise the efficiency of bacteria‐derived antibiotic defense in fungus‐growing ants. We found that symbiotic black yeasts acquire nutrients from the ants' bacterial mutualist, and suppress bacterial growth. Experimental manipulation of ant colonies and their symbionts shows that ants infected with black yeasts are significantly less effective at defending their fungus garden from Escovopsis, a prevalent and specialized pathogen. The reduction of mutualistic bacterial biomass on ants, likely caused by black yeast symbionts, apparently reduces the quantity of antibiotics available to inhibit the garden pathogen. Success of the ant–fungal mutualism is directly dependent on fungus garden health. Thus our finding that black yeasts compromise the ants' ability to deal with the garden parasite indicates that it is an integral component of the symbiosis. This is further evidence that a full understanding of symbiotic associations requires examining the direct and indirect interactions of symbionts in their ecological community context.