bluuebunny/crossref_metadata_2025 huggingface dataset:
Controllers or catalysts for change and improvement: would the real value for money auditors please stand up?
Authors: Morin Danielle
Published: January 2003

Public finance watchdogs and guardians of the public purse. These are just two of the labels branded on Auditors General over the years. Since their initiation into value for money audit only three decades ago, they have continually been exposing cases of public financing laxity. Each time the auditors approach a government organization, their reputation invariably precedes them. But what happens when the controllers decide to turn over a new leaf and become catalysts for change and improvement who have come to help managers improve their public organizations? Auditees, totally unaccustomed to seeking help from auditors, are understandably befuddled. On the other side of the coin, auditors are equally inexperienced at providing assistance to auditees. There is many a slip twixt cup and lip before the role confusion dissipates.
The 150‐hour rule: does it improve CPA exam performance?
Authors: Raghunandan K. , Read William J. , Brown Clifford D.
Published: January 2003

The American Institute of Certified Public Accountants (AICPA) has established 150 semester hours as the minimum education requirement to qualify to take the CPA examination. This educational requirement is generally believed to impose additional potential costs on students, academic accounting departments, public accounting firms, and audit clients. Since a goal of the 150‐hour rule is to improve the overall quality of work performed by CPAs, it is worthwhile to examine whether an association exists between the number of semester hours of education and performance on the CPA exam. After controlling for SAT scores (verbal and quantitative), accounting credit hours, and enrollment in CPA coaching courses, this study found that first‐time candidates, on a national basis, having a minimum of 150‐semester hours of education performed better on the CPA exam. We interpret these results as indicating that there are benefits to students, CPA firms, and their audit clients from the higher education standard.
AA1000 and SA8000 compared: a systematic comparison of contemporary accountability standards
Authors: Göbbels Math , Jonker Jan
Published: January 2003

One of the ways to deal with stakeholder issues, is the use and application of accountability standards. Two recent accountability standards (AA1000 and SA8000) will be the subject of comparison in this paper. Firstly, the constituent elements of these new standards will be briefly described. The main purpose of this paper is a systematic comparison of both standards on their object and scope, their normative perspective, the basic principles, their improvement perspective and their methodological perspective. The paper concludes by discussing the added value of both standards in their use and practical application. Questions are raised as to whether the instrumental “translation” of notions such as “accountability” and “social responsibility” offer the right support to deal with these issues on an organizational level.
The impact of presentation format and individual differences on the communication of information for management decision making
Authors: So Stella , Smith Malcolm
Published: January 2003

Accounting information is essentially multivariate and the relationships among variables may be difficult to establish. Differing multivariate information presentation methods may impact on the quality of the decisions made by users. Existing studies in this area have given scant attention to differences between individual users, despite earlier suggestions from the second author of this paper that both gender and personality might impact on information processing. This study focuses on the interaction of the decision maker (addressing issues of gender, personality, cognitive style and ability) with the data presentation method (including tables, graphical and pictorial methods) in the management decision making process. The paper reports on experiments conducted with respondents of varying degrees of accounting sophistication, using a failed/non‐failed decision environment. Results provide support for the use of graphical and pictorial methods as means of representing data for this decision task, while also identifying the influence of gender, spatial ability and tolerance of ambiguity. These findings have implications for the matching of information presentation with the characteristics of the decision maker in management decision making.
Auditing excellence in call centres: access is a corporate responsibility
Authors: Sewell‐Staples Warren J. , Dalrymple John F. , Phipps Katherine
Published: January 2003

This paper examines how the Australian Quality Council and the European Foundation for Quality Management address issues of access and corporate responsibility through their respective devices, namely the Australian Business Excellence Framework and the EFQM Excellence Model. It then examines the impact of the UK and Australian Disability Discrimination Legislation in light of UK and Australian studies on the provision of services for the hearing impaired by call centres.
A scheduling system for exploiting data and task parallelism on PC laboratory clusters
Authors: Chen Ying‐Nan , Tseng Li‐Ming , Chen Yi‐Ming
Published: January 2003

Presents a framework for deciding on a good execution strategy for a given program based on the available data and task parallelism in the program on PC laboratory clusters. Proposes a virtual cluster scheduling scheme to take account of the relationships between tasks for task parallelism, and also processor speed, processor load and network environment to balance load for data parallelism in a PC cluster environment. The approach is very effective in terms of the overall execution time, and demonstrates the feasibility of automatic cluster assignment, processor set selection and data partition functions for data and task parallel programs.
An outward design support system to increase self‐efficacy in online teaching and learning
Authors: Steinbronn Peggy E. , Merideth Eunice M.
Published: January 2003

The purpose of this article is to present an outward design for online support of a Web‐based, summer program that has been implemented at a medium‐sized, liberal arts university where student‐involved learning is at the heart of the mission, and technology is an important part of the vision of the institution. Because a sense of personal agency or self‐efficacy may be the most important determinant of motivation, the needs of both the teacher and learner need to be considered and integrated into the design and implementation of online support for teaching and learning.
Application of similitude techniques to functional testing of rapid prototypes
Authors: Dutson Alan J. , Wood Kristin L. , Beaman Joseph J. , Crawford Richard H. , Bourell David L.
Published: January 2003

Functional testing of rapid prototypes (RP) represents an exciting area of research in solid freeform fabrication. One approach to functional testing is to use similitude techniques to correlate the behavior of an RP model and a product. Previous research at UT, Austin has resulted in the development of an empirical similitude technique for correlating the behavior of parts with different material properties. Advances in the empirical similitude technique are presented in this paper. Sources of coupling between material properties and geometric shape that produce distortions in the current empirical similitude technique are outlined. A modified approach that corrects such distortions is presented. Numerical examples are used to illustrate both the current and the advanced empirical similitude methods.
Multi‐material and advanced geometry deposition via laser chemical vapor deposition
Authors: Bondi Scott N. , Johnson Ryan W. , Elkhatib Tarek , Gillespie Josh , Mi Jian , Jack Lackey W.
Published: January 2003

Laser chemical vapor deposition (LCVD) as a manufacturing process holds the potential to build compositionally and geometrically unique objects. Georgia Tech's LCVD system has been used in the past to create three‐dimensional and laminate structures out of carbon. Recently molybdenum and boron nitride were successfully deposited and upgrades to the system have allowed for higher spatial resolutions and more varied geometric capabilities. Upgrades include the addition of a fourth linear stage and implementation of an argon ion laser. Detailed thermal and fluid modeling have provided more insight as to the important parameters and characteristics of the LCVD process.
A study on effects of process parameters in rapid freeze prototyping
Authors: Bryant Frances D. , Sui Guanghua , Leu Ming C.
Published: January 2003

Rapid freeze prototyping is a relatively new solid freeform fabrication process, which builds a three‐dimensional part according to a CAD model by depositing and freezing water droplets layer by layer. A study on the effects of RFP process parameters including the nozzle scanning speed, droplet size, and droplet frequency in building ice parts with a single‐nozzle work head is made. Presented in this paper are the results of this study which indicate that these process parameters determine the ice layer thickness and ice line width, which in turn determine the surface roughness and the waiting time required after depositing each layer of water (i.e. between successive layers) during the ice part building process.
Recent developments in metal laminated tooling by multiple laser processing
Authors: Himmer Thomas , Techel Anja , Nowotny Steffen , Beyer Eckhard
Published: January 2003

Time reduction and quick geometrical changes of complex components and tools are currently the most important demands in product development. The manufacturing process presented in this paper is based on multiple additive and subtractive technologies such as laser cutting, laser welding, direct laser metal deposition and CNC milling. The process chain is similar to layer‐based Rapid Prototyping Techniques. In the first step, the 3D CAD geometry is sliced into layers by a specially developed software. These slices are cut by high speed laser cutting and then joined together. In this way laminated tools or parts are built. To improve surface quality and to increase wear resistance a CNC machining center is used. The system consists of a CNC milling machine, in which a 3 kW Nd:YAG laser, a coaxial powder nozzle and a digitizing system are integrated.
SIS – a new SFF method based on powder sintering
Authors: Khoshnevis Behrokh , Asiabanpour Bahram , Mojdeh Mehdi , Palmer Kurt
Published: January 2003

Selective inhibition of sintering (SIS) is a layered fabrication process which is capable of rapidly producing accurate functional parts out of polymers and metals using a relatively inexpensive machine. This article presents a brief overview of the research and development aimed at establishing the feasibility and the potential of the process.
Rapid prototyping for treatment of canine limb deformities
Authors: Harrysson Ola L.A. , Cormier Denis R. , Marcellin‐Little Denis J. , Jajal Ketan
Published: January 2003

This report describes Rapid Prototyping (RP) ‐aided assessment and preoperative planning for treatment of bilateral multifocal pelvic limb deformities in a 1 year old German Shepherd dog. Computed tomography (CT) scans were acquired on a General Electric CT scanner and converted to solid models using Mimics software from Materialise. Stereolithography patterns were prototyped using QuickCast build style on a SLA ‐190. Room temperature vulcanized silicone molds were constructed and three sets of polyurethane patterns were cast for pre‐surgical planning and rehearsal. The paper compares traditional osteotomy planning procedures using only radiographs and 2D CT images to planning with full‐scale physical biomodels. The biomodels had a clearly beneficial impact on the accuracy of surgery and positively influenced the clinical outcome.
Freeform fabrication of Nylon‐6 tissue engineering scaffolds
Authors: Das Suman , Hollister Scott J. , Flanagan Colleen , Adewunmi Adebisi , Bark Karlin , Chen Cindy , Ramaswamy Krishnan , Rose Daniel , Widjaja Erwin
Published: January 2003

The aim of this research is to develop, demonstrate and characterize techniques for fabricating such scaffolds by combining solid freeform fabrication and computational design methods. When fully developed, such techniques are expected to enable the fabrication of tissue engineering scaffolds endowed with functionally graded material composition and porosity exhibiting sharp or smooth gradients. Results of bio‐compatibility and in vivo implantation are presented.
Determinants of citizens’ attitudes toward police
Authors: Sims Barbara , Hooper Michael , Peterson Steven A.
Published: January 2003

The essence of community policing is a police‐community partnership for identifying, prioritizing and resolving citizen problems. The nature of community policing demands that attention be paid to public expectations of police, and implies listening to citizens and taking their problems seriously. A critical precursor to community policing is identifying citizens’ perceptions of police and their local neighborhoods. This paper presents findings from the Harrisburg Citizen Survey – 1999, in which citizens were asked a series of questions regarding their attitudes toward their local police, their fear of crime, and their perceptions of physical and social incivilities in their neighborhoods. The overall research question for the paper is “Can attitudes toward police be predicted by citizens’ perceptions of physical and social incivilities, their fear of crime, and contact with police, controlling for age, gender, race/ethnicity, household income, and level of education?”
The creation of specialized police gang units
Authors: Katz Charles M. , Maguire Edward R. , Roncek Dennis W.
Published: January 2003

Specialized police gang units are a rapidly emerging form of concentrated social control. Prior research, however, into the creation of specialized gang units suffers from a number of theoretical and methodological shortcomings. These shortcomings make it difficult to understand which of several potential explanations can best account for the establishment of specialized police gang units. Three perspectives are examined that have been hypothesized by policymakers and academics to explain the creation of gang units: contingency theory, social threat theory, and resource dependency theory. Using data obtained from police departments and communities around the country, the explanatory power of measures derived from these three theories is explored, while controlling for several environmental and organizational influences.
Sheriff’s deputies’ receptivity to organizational change
Authors: Cochran John K. , Bromley Max L. , Swando Matthew J.
Published: January 2003

Many criminologists have investigated the implementation process concerning the transformation toward community‐oriented policing, while researchers interested in the area of work and occupations and/or complex organizations have examined factors which contribute to or inhibit successful organizational change. To date, however, there has been little empirical research addressing the issue of employee receptivity to such change. The present study examines the effects of sheriff’s deputies’ socio‐demographic characteristics, work orientations, and perceptions of agency readiness/preparedness on their receptivity to organizational change. These deputies are employed in a sheriff’s department undergoing an agency‐wide shift toward community‐oriented policing. Our findings suggest that a service orientation and a belief that the agency has attained an appropriate level of preparedness positively influence their receptivity to change.
Partnerships, information and public safety
Authors: Lyons William
Published: January 2003

Congress has expressed concern that the Homeland Security agency might lack the power necessary to prevent future terrorist attacks. This paper argues that it less likely to be a lack of police power and more likely the misapplication of those powers that undermines the war on terror. Until one learns to police in ways that build trust within those communities least likely to willingly assist the police, no amount of additional funding or legal authority will increase the capacity of the police forces to gather the information needed. For neighborhood policing this means partnering with those most victimized by crime. For the war on terror, this means partnering with Arab‐American communities. This examination of partnerships provides a basis for understanding how likely it is that current neighborhood policing practices will support a successful war on terror.
Perceptions of the police
Authors: Brown Ben , Reed Benedict Wm
Published: January 2003

This research updates and expands upon Decker’s article “Citizen attitudes toward the police: a review of past findings and suggestions for future policy” by summarizing the findings from more than 100 articles on perceptions of and attitudes toward the police. Initially, the value of research on attitudes toward the police is discussed. Then the research pertaining to the impact of individual level variables (e.g. race) and contextual level variables (e.g. neighborhood) on perceptions of the police is reviewed. Studies of juveniles’ attitudes toward the police, perceptions of police policies and practices, methodological issues and conceptual issues are also discussed. This review of the literature indicates that only four variables (age, contact with police, neighborhood, and race) have consistently been proven to affect attitudes toward the police. However, there are interactive effects between these and other variables which are not yet understood; a finding which indicates that theoretical generalizations about attitudes toward police should be made with caution.
Drug‐testing police officers and police recruits
Authors: Mieczkowski Tom , Michelle Lersch Kim
Published: January 2003

The purpose of this article is to explore the issue of drug use among police officers and police recruits. Data from two large police agencies were used in this analysis. Results of the two most popular drug screens (urinalysis and hair analysis) in the identification of drug‐involved individuals, who are either currently employed in or applying for law enforcement positions, are presented and discussed. It is found that there is an identifiable group of people in policing which appears to be drug‐involved. It also appears that, at least in some situations, and for rapidly excreted drugs like cocaine, the use of urine may be producing underestimates of these groups. The data support the idea that policing agencies may want to consider using multiple drug‐testing modalities in order to maximize the identification of different drugs, whose characteristics can be an important consideration in interpreting drug test results.
Predicting the effects of military service experience on stressful occupational events in police officers
Authors: Patterson George T.
Published: January 2003

A review of the literature suggests that law enforcement agencies adopted a paramilitary model of management based on little empirical evidence supporting the suitability of this model. Moreover, relatively little is known about the effects of prior military service experience on the work events experienced by police officers. This paper will examine the effects of prior military service experience on exposure to organizational and field work events, and perceptions of stress among these events. The results show that more military experience did not significantly predict fewer organizational work events and lower perceptions of stress, or more field work events and greater perceptions of stress. More years of police experience and section assignment predicted fewer field work events, although perceptions of stress were not significantly lower. These results are discussed, as they compare with salient demographic variables found to influence work stress in police officers.
Traffic policing: an international perspective
Authors: Kratcoski Peter C. , Das Dilip K.
Published: January 2003

A total of 70 representatives from all continents of the world discussed the challenges of “traffic policing” in the twenty‐first century at the 7th Annual Meeting of the International Police Executive Symposium. Apart from the problems with which they have been confronted, the representatives also explained the proposed plans in their countries for finding solutions to them. There were many similar problems and similar solutions. But countries also differed from one another in many respects, reflecting their culture, economic conditions, political priorities, historical developments and other factors.
Police‐school resource officers’ and students’ perception of the police and offending
Authors: Jackson Arrick
Published: January 2003

Using a sample of 271 students from four schools in the southeast region of Missouri, this paper evaluates the impact of school resource officers (SRO) on young people’s views and attitudes about the police and offending. The results suggest that the use of an SRO in schools does not change students’ view of the police in general or offending. This weak impact is, at least in part, attributable to the negative contact that young people may have with the police and their SRO. This study concludes that, since the SRO has no significant impact on students’ perception of police or offending, then it would behoove school administrators to utilize their financial resources for counseling, student‐faculty crime prevention programs or delinquency awareness programs.
From Anchovies to Sardines and Back: Multidecadal Change in the Pacific Ocean
Authors: Chavez Francisco P. , Ryan John , Lluch-Cota Salvador E. , Ñiquen C. Miguel
Published: January 2003

In the Pacific Ocean, air and ocean temperatures, atmospheric carbon dioxide, landings of anchovies and sardines, and the productivity of coastal and open ocean ecosystems have varied over periods of about 50 years. In the mid-1970s, the Pacific changed from a cool “anchovy regime” to a warm “sardine regime.” A shift back to an anchovy regime occurred in the middle to late 1990s. These large-scale, naturally occurring variations must be taken into account when considering human-induced climate change and the management of ocean living resources.
Quantum Phase Transition in Organic Charge-Transfer Complexes
Authors: Horiuchi Sachio , Okimoto Yoichi , Kumai Reiji , Tokura Yoshinori
Published: January 2003

A phase transition in an organic charge-transfer complex, which originates from the neutral-ionic valence instability, can be tuned toward zero kelvin with use of external pressure or chemical modification as a control parameter. The phase diagram and observed dielectric behaviors are typical of quantum paraelectricity, yet this zero-kelvin transition point namely, the quantum critical point, accompanies large quantum fluctuation of the molecular charge, as demonstrated by the molecular vibrational mode spectra. The result indicates that the π-electron transfer between donor and acceptor molecules is coupled with the zero-point lattice dynamics around the quantum critical point.
Distinctive Roles of PHAP Proteins and Prothymosin-α in a Death Regulatory Pathway
Authors: Jiang Xuejun , Kim Hyun-Eui , Shu Hongjun , Zhao Yingming , Zhang Haichao , Kofron James , Donnelly Jennifer , Burns Dave , Ng Shi-chung , Rosenberg Saul , Wang Xiaodong
Published: January 2003

A small molecule, α-(trichloromethyl)-4-pyridineethanol (PETCM), was identified by high-throughput screening as an activator of caspase-3 in extracts of a panel of cancer cells. PETCM was used in combination with biochemical fractionation to identify a pathway that regulates mitochondria-initiated caspase activation. This pathway consists of tumor suppressor putative HLA-DR–associated proteins (PHAP) and oncoprotein prothymosin-α (ProT). PHAP proteins promoted caspase-9 activation after apoptosome formation, whereas ProT negatively regulated caspase-9 activation by inhibiting apoptosome formation. PETCM relieved ProT inhibition and allowed apoptosome formation at a physiological concentration of deoxyadenosine triphosphate. Elimination of ProT expression by RNA interference sensitized cells to ultraviolet irradiation–induced apoptosis and negated the requirement of PETCM for caspase activation. Thus, this chemical-biological combinatory approach has revealed the regulatory roles of oncoprotein ProT and tumor suppressor PHAP in apoptosis.
Mutations in the
DJ-1
Gene Associated with Autosomal Recessive Early-Onset Parkinsonism
Authors: Bonifati Vincenzo , Rizzu Patrizia , van Baren Marijke J. , Schaap Onno , Breedveld Guido J. , Krieger Elmar , Dekker Marieke C. J. , Squitieri Ferdinando , Ibanez Pablo , Joosse Marijke , van Dongen Jeroen W. , Vanacore Nicola , van Swieten John C. , Brice Alexis , Meco Giuseppe , van Duijn Cornelia M. , Oostra Ben A. , Heutink Peter
Published: January 2003

The
DJ-1
gene encodes a ubiquitous, highly conserved protein. Here, we show that
DJ-1
mutations are associated with PARK7, a monogenic form of human parkinsonism. The function of the DJ-1 protein remains unknown, but evidence suggests its involvement in the oxidative stress response. Our findings indicate that loss of DJ-1 function leads to neurodegeneration. Elucidating the physiological role of DJ-1 protein may promote understanding of the mechanisms of brain neuronal maintenance and pathogenesis of Parkinson's disease.
Diminished Pupillary Light Reflex at High Irradiances in Melanopsin-Knockout Mice
Authors: Lucas R. J. , Hattar S. , Takao M. , Berson D. M. , Foster R. G. , Yau K.-W.
Published: January 2003

In the mammalian retina, a small subset of retinal ganglion cells (RGCs) are intrinsically photosensitive, express the opsin-like protein melanopsin, and project to brain nuclei involved in non–image-forming visual functions such as pupillary light reflex and circadian photoentrainment. We report that in mice with the melanopsin gene ablated, RGCs retrograde-labeled from the suprachiasmatic nuclei were no longer intrinsically photosensitive, although their number, morphology, and projections were unchanged. These animals showed a pupillary light reflex indistinguishable from that of the wild type at low irradiances, but at high irradiances the reflex was incomplete, a pattern that suggests that the melanopsin-associated system and the classical rod/cone system are complementary in function.
Anthropogenic CO
2
Uptake by the Ocean Based on the Global Chlorofluorocarbon Data Set
Authors: McNeil Ben I. , Matear Richard J. , Key Robert M. , Bullister John L. , Sarmiento Jorge L.
Published: January 2003

We estimated the oceanic inventory of anthropogenic carbon dioxide (CO
2
) from 1980 to 1999 using a technique based on the global chlorofluorocarbon data set. Our analysis suggests that the ocean stored 14.8 petagrams of anthropogenic carbon from mid-1980 to mid-1989 and 17.9 petagrams of carbon from mid-1990 to mid-1999, indicating an oceanwide net uptake of 1.6 and 2.0 ± 0.4 petagrams of carbon per year, respectively. Our results provide an upper limit on the solubility-driven anthropogenic CO
2
flux into the ocean, and they suggest that most ocean general circulation models are overestimating oceanic anthropogenic CO
2
uptake over the past two decades.
Adventures of a Pioneer Mayanist
Authors: Webster David
Published: January 2003

Alfred Maudslay and the Maya
. A Biography. Ian Graham. University of Oklahoma Press, Norman, OK, 2002. 323 pp. $39.95. ISBN 0-8061-3450-X.

Drawing on Maudslay's publications, field notes, and family papers, Graham explores the life and work of one of the pioneer investigators of ancient Mayan ruins.
KCNQ1 Gain-of-Function Mutation in Familial Atrial Fibrillation
Authors: Chen Yi-Han , Xu Shi-Jie , Bendahhou Saı̈d , Wang Xiao-Liang , Wang Ying , Xu Wen-Yuan , Jin Hong-Wei , Sun Hao , Su Xiao-Yan , Zhuang Qi-Nan , Yang Yi-Qing , Li Yue-Bin , Liu Yi , Xu Hong-Ju , Li Xiao-Fei , Ma Ning , Mou Chun-Ping , Chen Zhu , Barhanin Jacques , Huang Wei
Published: January 2003

Atrial fibrillation (AF) is a common cardiac arrhythmia whose molecular etiology is poorly understood. We studied a family with hereditary persistent AF and identified the causative mutation (S140G) in the
KCNQ1
(
KvLQT1
) gene on chromosome 11p15.5. The
KCNQ1
gene encodes the pore-forming α subunit of the cardiac
I
Ks
channel (KCNQ1/KCNE1), the KCNQ1/KCNE2 and the KCNQ1/KCNE3 potassium channels. Functional analysis of the S140G mutant revealed a gain-of-function effect on the KCNQ1/KCNE1 and the KCNQ1/KCNE2 currents, which contrasts with the dominant negative or loss-of-function effects of the KCNQ1 mutations previously identified in patients with long QT syndrome. Thus, the S140G mutation is likely to initiate and maintain AF by reducing action potential duration and effective refractory period in atrial myocytes.
Ringlike Structure of the
Deinococcus radiodurans
Genome: A Key to Radioresistance?
Authors: Levin-Zaidman Smadar , Englander Joseph , Shimoni Eyal , Sharma Ajay K. , Minton Kenneth W. , Minsky Abraham
Published: January 2003

The bacterium
Deinococcus radiodurans
survives ionizing irradiation and other DNA-damaging assaults at doses that are lethal to all other organisms. How
D
.
radiodurans
accurately reconstructs its genome from hundreds of radiation-generated fragments in the absence of an intact template is unknown. Here we show that the
D. radiodurans
genome assumes an unusual toroidal morphology that may contribute to its radioresistance. We propose that, because of restricted diffusion within the tightly packed and laterally ordered DNA toroids, radiation-generated free DNA ends are held together, which may facilitate template-independent yet error-free joining of DNA breaks.
Dispersal, Environment, and Floristic Variation of Western Amazonian Forests
Authors: Tuomisto Hanna , Ruokolainen Kalle , Yli-Halla Markku
Published: January 2003

The distribution of plant species, the species compositions of different sites, and the factors that affect them in tropical rain forests are not well understood. The main hypotheses are that species composition is either (i) uniform over large areas, (ii) random but spatially autocorrelated because of dispersal limitation, or (iii) patchy and environmentally determined. Here we test these hypotheses, using a large data set from western Amazonia. The uniformity hypothesis gains no support, but the other hypotheses do. Environmental determinism explains a larger proportion of the variation in floristic differences between sites than does dispersal limitation; together, these processes explain 70 to 75% of the variation. Consequently, it is important that management planning for conservation and resource use take into account both habitat heterogeneity and biogeographic differences.
Satellite Observations of Magnetic Fields Due to Ocean Tidal Flow
Authors: Tyler Robert H. , Maus Stefan , Lühr Hermann
Published: January 2003

The ocean is an electrically conducting fluid that generates secondary magnetic fields as it flows through Earth's main magnetic field. Extracting ocean flow signals from remote observations has become possible with the current generation of satellites measuring Earth's magnetic field. Here, we consider the magnetic fields generated by the ocean lunar semidiurnal (M
2
) tide and demonstrate that magnetic fields of oceanic origin can be clearly identified in satellite observations.
Nanoparticle Assembly and Transport at Liquid-Liquid Interfaces
Authors: Lin Y. , Skaff H. , Emrick T. , Dinsmore A. D. , Russell T. P.
Published: January 2003

The self-assembly of particles at fluid interfaces, driven by the reduction in interfacial energy, is well established. However, for nanoscopic particles, thermal fluctuations compete with interfacial energy and give rise to a particle-size–dependent self-assembly. Ligand-stabilized nanoparticles assembled into three-dimensional constructs at fluid-fluid interfaces, where the properties unique to the nanoparticles were preserved. The small size of the nanoparticles led to a weak confinement of the nanoparticles at the fluid interface that opens avenues to size-selective particle assembly, two-dimensional phase behavior, and functionalization. Fluid interfaces afford a rapid approach to equilibrium and easy access to nanoparticles for subsequent modification. A photoinduced transformation is described in which nanoparticles, initially soluble only in toluene, were transported across an interface into water and were dispersed in the water phase. The characteristic fluorescence emission of the nanoparticles provided a direct probe of their spatial distribution.
Role of a Highly Conserved Bacterial Protein in Outer Membrane Protein Assembly
Authors: Voulhoux Romé , Bos Martine P. , Geurtsen Jeroen , Mols Maarten , Tommassen Jan
Published: January 2003

After transport across the cytoplasmic membrane, bacterial outer membrane proteins are assembled into the outer membrane. Meningococcal Omp85 is a highly conserved protein in Gram-negative bacteria, and its homolog Toc75 is a component of the chloroplast protein-import machinery. Omp85 appeared to be essential for viability, and unassembled forms of various outer membrane proteins accumulated upon Omp85 depletion. Immunofluorescence microscopy revealed decreased surface exposure of outer membrane proteins, which was particularly apparent at the cell-division planes. Thus, Omp85 is likely to play a role in outer membrane protein assembly.
Dyskeratosis Congenita and Cancer in Mice Deficient in Ribosomal RNA Modification
Authors: Ruggero Davide , Grisendi Silvia , Piazza Francesco , Rego Eduardo , Mari Francesca , Rao Pulivarthi H. , Cordon-Cardo Carlos , Pandolfi Pier Paolo
Published: January 2003

Mutations in
DKC1
cause dyskeratosis congenita (DC), a disease characterized by premature aging and increased tumor susceptibility. The
DKC1
protein binds to the box H + ACA small nucleolar RNAs and the RNA component of telomerase. Here we show that hypomorphic
Dkc1
mutant (

Dkc1
m

) mice recapitulate in the first and second generations (G1 and G2) the clinical features of DC.

Dkc1
m

cells from G1 and G2 mice were impaired in ribosomal RNA pseudouridylation before the onset of disease. Reductions of telomere length in

Dkc1
m

mice became evident only in later generations. These results suggest that deregulated ribosome function is important in the initiation of DC, whereas telomere shortening may modify and/or exacerbate DC.
Regulation of Blood and Lymphatic Vascular Separation by Signaling Proteins SLP-76 and Syk
Authors: Abtahian Farhad , Guerriero Anastasia , Sebzda Eric , Lu Min-Min , Zhou Rong , Mocsai Attila , Myers Erin E. , Huang Bin , Jackson David G. , Ferrari Victor A. , Tybulewicz Victor , Lowell Clifford A. , Lepore John J. , Koretzky Gary A. , Kahn Mark L.
Published: January 2003

Lymphatic vessels develop from specialized endothelial cells in preexisting blood vessels, but the molecular signals that regulate this separation are unknown. Here we identify a failure to separate emerging lymphatic vessels from blood vessels in mice lacking the hematopoietic signaling protein SLP-76 or Syk. Blood-lymphatic connections lead to embryonic hemorrhage and arteriovenous shunting. Expression of
slp-76
could not be detected in endothelial cells, and blood-filled lymphatics also arose in wild-type mice reconstituted with SLP-76–deficient bone marrow. These studies reveal a hematopoietic signaling pathway required for separation of the two major vascular networks in mammals.
Bose-Einstein Condensation of Cesium
Authors: Weber Tino , Herbig Jens , Mark Michael , Nägerl Hanns-Christoph , Grimm Rudolf
Published: January 2003

Bose-Einstein condensation of cesium atoms is achieved by evaporative cooling using optical trapping techniques. The ability to tune the interactions between the ultracold atoms by an external magnetic field is crucial to obtain the condensate and offers intriguing features for potential applications. We explore various regimes of condensate self-interaction (attractive, repulsive, and null interaction strength) and demonstrate properties of imploding, exploding, and non-interacting quantum matter.
Alternative Approaches to Healing
Authors: Lederer Susan E.
Published: January 2003

Nature Cures
. The History of Alternative Medicine in America. James C. Whorton. Oxford University Press, New York, 2002. 384 pp. $30, £22.95. ISBN 0-19-514071-0.

Whorton offers a context for current controversy on the role of unconventional medicine in health care by discussing the past two centuries of interactions between mainstream medicine and its numerous unorthodox competitors.
Fast, efficient syntheses of linear poly(dipyrromethene)s
Authors: Chen Qingqi , Dolphin David
Published: January 2003

The synthesis of three octapyrrolic, 810, and four dodecapyrrolic, 1518, oligomers is reported. They are linear poly(dipyrromethene)s and potential ligands as building blocks for supramolecular architectures through self-assembly. Octapyrrolic oligomers 810 were prepared in 9095% yields by condensation of 2 equiv of a tripyrrolic compound 4 with 1 equiv of diformyldipyrrolic compounds 57. A similar procedure, involving the condensation of 2 equiv of a pentapyrrolic starting material 13 with 1 equiv of 57 or 14, was found to give rise to the corresponding dodecameric systems 1518 in 4156% yields.Key words: poly(dipyrromethene), linear polypyrroles, dipyrromethane, dipyrromethene.
pH-controlled location and metalation of an amphiphilic porphyrin in sodium dodecyl sulfate micelle
Authors: Guo Lin , Liang Ying-qiu
Published: January 2003

5,10,15-Tri(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl)porphyrin (P) was solubilized in sodium dodecyl sulfate (SDS) micelle solutions. Taking advantage of the protonation and deprotonation properties of the amphiphilic porphyrin allowed the study of the pH-controlled transfer process of P in SDS micelle by means of UVvis and fluorescence spectra. In neutral SDS micelle, P may be protonated and located at the outer surface of the micelle. In mildly basic conditions the hydrophilic ability of P decreases and the porphyrin moiety may transfer to the inner layer of SDS micelle. In strong basic conditions the porphyrin may transfer back to the outer aqueous surface of the micelle. The kinetic study of the porphyrin complexed with Cu(II) shows that the metalation rate of P could be controlled by changing the pH.Key words: porphyrin, location, metalation, sodium dodecyl sulfate, micelle.
Lamellar polysilicate nanocomposite materials: Intercalation of polyethylene glycols into protonated magadiite
Authors: Binette Marie-Josée , Detellier Christian
Published: January 2003

This paper reports the direct intercalation of organic polymers into the interlamellar spaces of the layered polysilicate magadiite. Poly(ethylene glycols) (PEG 3400 and PEG 1000) were intercalated into acidified magadiite (H-magadiite) by displacing a dipolar aprotic solvent (e.g., dimethylsulfoxide (DMSO)) from the H-magadiite  DMSO intercalate. This was done directly from the polymer melt at 155°C. The polysilicid acid (H-magadiite) was obtained by HCl titration of the sodic form of magadiite obtained by hydrothermal synthesis. Dipolar aprotic solvents (dimethylsulfoxide, N-methylformamide, and hexamethylphosphorictriamide) were intercalated in the interlamellar spaces of H-magadiite. PEG 3400 and PEG 1000 were then intercalated by dispersing the H-magadiite intercalates in a large excess of the polymers heated above their fusion temperature, without any solvent. The resulting polymer intercalated H-magadiite nanocomposites were isolated and purified and were shown by chemical analysis to have chemical formulae of H2Si14O29(-OCH2CH2-)3.1 and H2Si14O29(-OCH2CH2-)2.9, respectively, in agreement with a structure in which one unit cell of magadiite corresponds to three oxyethylene units. The dipolar aprotic solvents have been completely removed from the interlamellar spaces. 13C NMR dipolar diphasing techniques show that the polymer chains in the interlamellar spaces of H-magadiite are more constrained than in the bulk polymer. 29Si NMR spectra show that the structure of magadiite is unchanged by the two processes of intercalation. The polymer intercalates are characterized by interlamellar spacings of 4.6 and 4.4 Å, as determined by XRD. These values correspond to a flattened arrangement of the polymer chains in the interlamellar spaces. This is also in agreement with DSC data, which demonstrate that the polymer chains are no longer in the aggregation state characteristic of the bulk polymer.Key words: lamellar polysilicates, polyethylene glycols, nanocomposite materials, polymer intercalation, magadiite.
Ryanoids and related compounds  Chemoselective electrocatalytic hydrogenation of alkyl α-pyrrole carboxylates: Selective hydrogenation of ryanodine
Authors: Ruest Luc , Ménard Hugues , Moreau Vincent , Laplante François
Published: January 2003

A study of the electrocatalytic hydrogenation (ECH) process of pyrrole and different alkyl pyrrole-2-carboxylates is presented. Once hydrogenated, the alkyl pyrrole-2-carboxylate becomes an ester of proline, an important natural amino acid. The process is chemoselective to the pyrrole ring. Ryanodine is a natural ryanoid known to be biologically active. The tetrahydroryanodine derivative thus obtained may now represent a molecule of high biological interest. The hydrogenation of ryanodine is possible with electrocatalytic and catalytic processes. In both cases the reaction is not diastereoselective.Key words: electrocatalytic hydrogenation, proline esters, ryanodine, tetrahydroryanodine.
Synthesis, characterization, and X-ray crystal structures of Co(II) and La(III) complexes of a pyridine containing self-assembling system and solution studies of the Co(II) complex
Authors: Moghimi A , Ranjbar M , Aghabozorg H , Jalali F , Shamsipur M , Chadha Kaj K
Published: January 2003

The complexes [pyda.H]2[Co(pydc)2]·H2O (I) and [pyda·H]2[La2(pydc)4(H2O)4].2H2O (II) were prepared from the complexation of a novel pyridine containing self-assembling system LH2, ([pyda·H2]2+[pydc]2) (pyda = 2,6-pyridinediamine and pydc·H2 = 2,6-pyridinedicarboxylic acid), with cobalt(II) and lanthanum(III) salts in 82% and 74% yields, respectively. The characterizations were performed using elemental analysis, ESI mass spectroscopy as well as 1H and 13C solution NMR spectroscopy, and X-ray crystallography. The crystal systems I and II are monoclinic and triclinic with space groups P21/n and P[Formula: see text] respectively. Coordination number around each Co atom is six with distorted octahedral geometry, while coordination number around each La atom is nine with highly distorted tricapped trigonal prism geometry. The paramagnetic Co(II) and diamagnetic La(III) complexes show 1H NMR resonances of both anionic [pydc]2- and cationic counter ion [pyda·H]+ in DMSO-d6. The complexation reactions of the complex I in aqueous solution were investigated by potentiometric pH titrations and the equilibrium constants for all major complexes formed are described. The results are presented in the form of distribution diagrams revealing the concentrations of individual complex species as a function of pH. The results revealed that at a pH range 4.04.5 the major complex species is [(pyda·H)]2[Co(pydc)2].Key words: self-assembly, X-ray crystal structure, Co(II) complex, La(III) complex, 2,6- pyridinedicarboxylic acid, 2,6-pyridinediamine, hydrogen bonding.
Magnetic properties of some FeS six-membered ring compounds
Authors: Liu Ping , Liu Jia Cheng , Wang Jian , Cheng Jian Kai , Li Wen Jie , Huang Xin
Published: January 2003

The Fe3S3 cluster is an important component located in the active centres of some ironsulfur proteins. The magnetic properties of three Fe3S3 compounds have been studied for the first time by fitting the temperature-dependent magnetic susceptibilities. The calculated g factors and J couplings reproduce the magnetic behavior of such compounds very well. There is an antiferromagnetic spin interaction between pairs of magnetic centers in the Fe3S3 cluster compounds. The magnetic exchange of Fe-S-Fe model magnetic molecules is discussed.Key words: Fe3S3 compounds, magnetic, antiferromagnetic.
Antibody-catalyzed formation of a 14-membered ring lactone
Authors: Pungente Michael D , Weiler Larry , Ziltener Hermann J
Published: January 2003

Monoclonal antibody (MAb) F123, raised against a macrocyclic phosphonate transition-state analogue, catalyzed an intramolecular transesterification of the corresponding hydroxy ester to give a 14-membered ring lactone. The MAb reaction displayed enzyme-like MichaelisMenten kinetics with a Km of 255 µM and a kcat of 0.01 min1 based on p-nitrophenol release and calculated on an active-site basis. Substrate specificity and competitive inhibition by a transition state analogue (Ki = 3 µM) demonstrated that the catalytic activity was associated with binding in the antibody-combining site. The lactone product was isolated from a large-scale catalytic experiment through ether extraction and identified by gas chromatography  mass spectroscopy.Key words: macrocyclization, lactones, catalytic antibodies.
Synthesis and structural characterization of binuclear titanium(IV) and tantalum(V) cyclopentadienyl complexes containing bridging phosphinate ligands
Authors: Dorn Hendrik , Vejzovic Emira , Lough Alan J , Manners Ian
Published: January 2003

The reaction of Ph2P(O)(OSiMe3) with [(η5-C5H5)TiCl3] or [(η5-C5Me5)TaCl4] in dichloromethane yields the complexes [{(η5-C5H5)TiCl2(µ-Ph2PO2)}2] (1) or [{(η5-C5Me5)TaCl3(µ-Ph2PO2)}2] (2), respectively. Structural analysis of 1 and 2 by single-crystal X-ray diffraction revealed the presence of eight-membered metallacycles consisting of bridgingbidentate diphenylphosphinate groups between two metal centers.Key words: inorganic rings, phosphinate complexes, tantalum, titanium.
Kinetics and mechanism of the oxidation of disaccharides by CrVI
Authors: Roldán Viviana , Carlos González Juan , Santoro Mabel , García Silvia , Casado Nieves , Olivera Silvina , Boggio Juan Carlos , Salas-Peregrin Juan Manuel , Signorella Sandra , Sala Luis F
Published: January 2003

The oxidation of D-lactose, D-maltose, D-melibiose, and D-cellobiose by CrVIyields the corresponding aldobionic acid and Cr3+as final products when an excess of reducing disaccharide over CrVIis used. The rate law for the CrVIoxidation reaction is expressed by d[CrVI]/dt = kH[disaccharide][CrVI], where the second-order kinetic constant, kH, depends on [H+]. The relative reactivity of the disaccharides with CrVIis expressed as follows: Mel > Lac > Cel > Mal, at 33°C. In acid medium, intermediate CrVforms and reacts with the substrate faster than CrVI. The EPR spectra show that five- and six-coordinate oxo-CrVintermediates are formed, with the disaccharide acting as bidentate ligand. Five-coordinate oxo-CrVspecies are present at any [H+], whereas six-coordinate ones are observed only at pH < 2, where they rapidly decompose to the redox products. In the pH 37 range, where hexa-coordinate oxo-CrVspecies are not observed, CrVcomplexes are stable enough to remain in solution from several days to several months.Key words: chromium, saccharides, kinetics, EPR.
Local modes
Authors: Henry Bryan R , Kjaergaard Henrik G
Published: January 2003

The historical background for the development of the local mode approach is reviewed, including the critical role of the radiation field. The harmonically coupled anharmonic oscillator model is described. Local modes have been used in the interpretation of XH stretching overtone spectra. These spectra can be used as sensitive probes of molecular properties such as bond length and molecular conformation. Examples of these spectral features are discussed. An intensity theory has been developed that permits the accurate calculation of relative and absolute overtone intensities. In molecules with low barriers to methyl rotation, torsional states contribute to the XH stretching band profile. A successful theoretical approach is presented that accounts for these effects and provides insight into the vibrational dynamics. The application of calculated local mode overtone spectra to atmospheric chemistry is discussed.Key words: local mode, overtone, vibrational intensity.