bluuebunny/crossref_metadata_2025 huggingface dataset:
Lanthanides: Homogeneous Catalysis
Authors: Yao Yingming , Nie Kun
Published: December 2012

Organolanthanide complexes are those compounds containing Ln‐X σ‐bonds, such as alkyls, amides, hydrides, alkoxides, and aryloxides, which readily hydrolyze when they are exposed to moist air, with the formation of the lanthanide hydroxides. The potential applications of organolanthanide complexes in homogeneous catalysis are the main driving force for the development of organolanthanide chemistry. In the past decades, organolanthanide chemistry has received a rapid development, and a variety of ligand systems including cyclopentadienyl and noncyclopentadienyl groups were developed to stabilize numerous organolanthanide complexes. Indeed, some organolanthanide complexes show exciting catalytic activity in homogeneous catalysis, both in organic synthesis and polymerization. For example, some organolanthanide complexes can efficiently catalyze organic transformations such as hydroelementations of alkenes, the amidation of aldehydes with amines, Tishchenko reaction, addition of amines to nitriles, and guanylation of carbodiimides. Organolanthanide complexes can also catalyze the polymerization of some nonpolar and polar monomers. In this chapter, the recent developments of the application of organolanthanide complexes in homogeneous catalysis are summarized.
Lanthanides: Heterogeneous Catalysis
Authors: Walrod John Hamilton , Atwood David A.
Published: December 2012

Rare earth oxides, which generally take the form Ln
2
O
3,
are widely used in heterogeneous catalysis. This article provides a brief description of the Ln
2
O
3
oxides, which includes a comparison of their chemical and physical properties. The basicity of heterogeneous oxides is examined, and the different pKa's on the surface are modeled. The catalytic properties of the oxides will be correlated with their various chemical and physical properties. Several different examples of their use in rare earth heterogeneous catalysis will be described including oxidative methane coupling and transesterification of triglycerides.
Lanthanides: Supramolecular Chemistry
Authors: Kitchen Jonathan A. , Gunnlaugsson Thorfinnur
Published: December 2012

In this chapter, some of the most recent examples of the use of lanthanide ions in the formation of functional supramolecular complexes and self‐assemblies are detailed. The examples focus mainly on the use of the lanthanides to direct the synthesis of complex structures published within the last few years, in the form of mononuclear or polynuclear complexes, where the physical properties of the lanthanides, such as their luminescent and magnetic properties, have been exploited to form functional supramolecular assemblies, e.g., luminescent‐based sensors or single molecule magnets (SMMs). The use of the lanthanides to direct the formation of complex self‐assembly architectures is an area of research that is rapidly growing in the field of lanthanide‐based supramolecular chemistry, where the coordination requirements of the lanthanides when coupled with ligand design can give rise to the formation of highly novel and structurally complex species.
Lanthanides: Amino Acid Compounds
Authors: Zheng Zhiping
Published: December 2012

The synthetic and structural chemistry of lanthanide complexes with α‐amino acids under low‐ and high‐pH conditions is summarized. The preparative methods, diverse coordination modes, fascinating solid‐state structures, and solution behavior of such complexes are discussed. Under acidic conditions, only the carboxylate group of the amino acid participates in the metal coordination. For those with a side‐chain carboxylate group, more extensive bridging interactions of the ligand and the lanthanide ions are identified. Under physiological or even higher‐pH conditions, both the amino and carboxylate groups, be they skeletal or present in the side chain, could be coordinating, leading to much more diverse coordination modes of these unique ligands in their lanthanide complexes. Distinct from their low‐pH counterparts, complexes obtained under higher‐pH conditions are products of lanthanide hydrolysis, limited by the supporting amino acid ligands. Presence of structurally well‐defined polynuclear lanthanide–oxo/hydroxo cluster motif is characteristic of these interesting compounds that provide fundamental insight into the lanthanide interactions with biological environment.
Lanthanides: Sensors for Lanthanides and Actinides
Authors: Vargas‐Zúñiga Gabriela I. , Sessler Jonathan L.
Published: December 2012

In this chapter, recent advances in the area of chemical‐based lanthanide and actinide sensing are summarized, and several representative examples of molecules that have been employed as sensors for the lanthanide and actinide ions using either optical or electrochemical monitoring (“read out”) techniques have been detailed. Because it represents an area where specific receptor design has played an instrumental role, the authors focus on detection strategies based on ion‐selective electrodes, as well as those that give rise to an easy‐to‐monitor optical response (so‐called optodes).
Lanthanides: Luminescence Applications
Authors: Andres Julien , Chauvin Anne‐Sophie
Published: December 2012

This chapter is an illustration of the fundamental concepts that are described elsewhere. The reader finds information regarding the visible as well as the NIR‐emitting lanthanide ions, which are illustrated by spectra and the main transitions involved. The chapter demonstrates how to characterize the color from a luminescent emission, how to define a color space, and the potential uses of lanthanide‐emitting complexes. Upconversion processes are then described, with their potential applications, followed by the principle of LASER (light amplification by stimulated emission of lanthanide radiation). A short review of some of the requirement for designing an efficient luminescent lanthanide complex is then presented, and illustrated by several families of ligands. A discussion of some of the properties of these ligands helps understanding why they have been extensively used for years in numerous applications. Some dedicated aspects are treated, such as the problem of solubility, stability, and sensing ability.
Lanthanides: Siloxides
Authors: Krempner Clemens , McNerney Brian
Published: December 2012

The chemistry of rare earth siloxides, also referred to as rare earth silanolates or silyloxides, is reviewed. After a brief discussion of the electronic and steric properties of various siloxide ligands, the synthetic and structural aspects of divalent, trivalent, and tetravalent rare earth siloxides are presented along with selected reactivity studies. The main focus, however, is on the chemistry of trivalent rare earth siloxides with special emphasis given to the steric and electronic influence of the siloxide ligand on the structure, stability, and reactivity on the supported rare earth metal. Applications of some heteroleptic rare earth siloxides as homogeneous catalysts in the polymerization of isoprene and hydrosilylation of olefins are included and briefly discussed.
DNA-Reparatur und Alterung
Authors: Schumacher B.
Published: December 2012

Die letzten Jahre haben erhebliche Fortschritte im Verständnis der Biologie des Alterns erbracht. Die Bedeutung genomischer Instabilität als kausaler Faktor der funktionellen Degeneration in der Alterung wurde besonders durch Untersuchungen an progeroiden Syndromen deutlich. Humane Progerien stellen seltene Erbkrankheiten dar, welche von ausgesprochener Diversität und Komplexität gekennzeichnet sind. Die Manifestationen progeroider Syndrome reflektieren sowohl die Funktion der involvierten DNA-Reparatur- und Schadensantwortmechanismen als auch die komplexen physiologischen Reaktionen auf DNA-Läsionen. Untersuchungen an biologischen Modellsystemen progeroider Erkrankungen haben Verbindungen zwischen der DNA-Schadensantwort und genetischen Regulationsmechanismen der Alterung aufgezeigt. Durch diese Erkenntnisse hat sich einerseits das Verständnis der Ursachen von Progerie und Alterung verbessert, andererseits werden neue Strategien erkenntlich, welche zur Entwicklung präventiver Interventionen zur Behandlung progeroider Symptome und altersbedingter Erkrankungen führen könnten.
Cockayne-Syndrom
Authors: Kamenisch Y. , Berneburg M.
Published: December 2012

Das Cockayne-Syndrom (CS) ist eine seltene, autosomal-rezessive Erkrankung, charakterisiert durch vorzeitige Alterungssymptomatik mit Degeneration des zentralen Nervensystems, Verlust des subkutanen Fettgewebes und Kachexie. Auslöser dieser Erkrankung sind autosomal-rezessiv vererbte Mutationen im CSA- und CSB-Gen. Im Zellkern sind das CSA- und das CSB-Protein sowohl an der DNA-Reparatur als auch der Transkription beteiligt. Außerhalb des Zellkerns schützen die CS-Proteine im Mitochondrium vor oxidativ induzierten mitochondrialen (mt) DNA-Schäden und spielen somit möglicherweise eine wichtige Rolle beim altersbedingten Verlust des subkutanen Fettgewebes. Damit ist das CS nicht nur wichtig als Modellerkrankung zur Untersuchung molekularer Mechanismen der DNA-Reparatur, sondern auch für das Verständnis der Ursachen des Alterungsprozesses.
Natural history of adolescent idiopathic scoliosis: A tool for guidance in decision of surgery of curves above 50°
Authors: Danielsson Aina J.
Published: December 2012

The purpose of this lecture was to give an overview of the natural history of adolescent idiopathic scoliosis (AIS), in order to serve as guidance in the decision of performing surgery or not for the specific patient with AIS. A literature review was performed. Studies concerning long-term outcome in patients with adolescent idiopathic scoliosis that had received no treatment were used. Outcome in terms of curve size, pulmonary function, back function and quality or life/social life was compared. The literature review showed that single thoracic curves of 50°–75° progress 0.73°/year over a 40-year period. AIS do not result in increased mortality, but pulmonary symptoms may be associated with larger curves. Back pain is more frequent among patients with AIS. No study using modern quality of life questionnaires exists, but for social function, childbearing, and marriage no apparent disadvantageous effects were reported compared to the healthy population. The conclusion is that most individuals with AIS and moderate curve size around maturity function well and lead an acceptable life in terms of work and family. Some patients with larger curves have pulmonary problems, but not to the extent that this affects the life span. This needs to be taken into account when discussing surgery with the individual patient.
European oak powdery mildew: impact on trees, effects of environmental factors, and potential effects of climate change
Authors: Marçais Benoit , Desprez-Loustau Marie-Laure
Published: December 2012

• Context

Powdery mildew is one of the most common diseases of oaks in Europe. After alarming reports in the beginning of the twentieth century following the presumed introduction of the invasive fungus, the disease has become familiar to foresters. However, its impact may vary greatly according to intrinsic and extrinsic factors.

• Aims

We aimed at providing updated and synthesised information on the impact of powdery mildew on oak and on the effects of environment on disease.

• Methods

A comprehensive literature review was performed, including old reports of the early epidemics to more recent data.

• Results

Tree growth patterns are of critical importance to explain the severity of the disease and the differences between juvenile and mature trees. A critical element, especially for infection of mature trees, is the availability of spores during the production of the first leaf flush. High disease impact is often related to modified growth patterns, either by environmental factors (insects or frost) or silvicultural practices (e.g., coppicing).

• Conclusion

Powdery mildew can have important impacts in natural oak regenerations and a significant role in decline of mature trees. Climate change might influence the disease severity mainly by altering the host pathogen phenological synchrony. Process-based models are required for reliable predictions.
Preoperative dexmedetomidine prevents tourniquet‐induced hypertension in orthopedic operation during general anesthesia
Authors: Lu Yao , Zhang Ye , Dong Chun‐Shan , Yu Jun‐Ma , Wong Gordon Tin‐Chun
Published: December 2012

This study was a double‐blinded randomized control trial designed to investigate the hemodynamic effects of dexmedetomidine on prolonged tourniquet inflation. Thirty‐seven patients scheduled for elective orthopedic surgery of the lower limb under general anesthesia were recruited. They were randomly assigned to receive intravenous dexmedetomidine (DEX, 0.5 μg/kg; n = 18) or normal saline (CON; n = 19) before tourniquet inflation. Arterial blood pressure and heart rate were recorded every 10 minutes until 60 minutes after the start of tourniquet inflation and again immediately after deflation. In the DEX group, arterial pressure was not significantly changed, but in the CON group arterial pressure was significantly increased at 40, 50, and 60 minutes after the start of tourniquet inflation. Development of more than 30% increase in arterial pressure during tourniquet inflation was more frequent in the CON group than in the DEX group. Preoperative intravenous dexmedetomidine could therefore prevent tourniquet‐induced hypertension in patients undergoing general anesthesia.
Manufacturing ‘Quiet Arabs’ in Israel: Ethnicity, Media Frames and Soft Power
Authors: Jamal Amal
Published: December 2012

This article has three aims. First, it aims to explain how media framing forms a central soft power tool utilized by states for the political control of social groups antagonistic to the states' dominant ideology. For that purpose it addresses Israeli state efforts to penetrate the native Arab community that remained within its borders after the 1948 war, seeking to create submissive ‘quiet Arab’ citizens. Second, it examines the role of Jewish-Arab (Mizrahi) professional opinion-makers in creating and maintaining this framing. Third, it demonstrates that efforts made by states to influence ‘captive audiences’ by media outlets in the global age can be successful only if they meet the needs of the target community.
Dynamic Behaviors of a Circular Worktable Mounted on Closed-Type Hydrostatic Thrust Bearing Compensated by Constant Compensations
Authors: Kang Y. , Chou H.-C. , Wang Y.-P. , Chen C.-H. , Weng H. C.
Published: December 2012

This study investigates the influences of constant compensations which are produced by capillary or constant flow pump on the dynamic characteristics of a circular worktable supported by a closed-type hydrostatic thrust bearing. The dynamic behaviors of this worktable are analyzed by using Runge-Kutta method to solve the coupled motion equation of worktable and pressure equations of hydrostatic film flow. For various supply pressure parameters, external loads, and varieties of design parameters, the dynamic responses of worktable subjected to both external excitations of harmonic force and step force are simulated, respectively. The results reveal the influences of both constant compensations on the dynamic characteristics of hydrostatic bearing by the different responses of worktable and make the appropriate parameters of design can be found for the worktable-bearing system. The accomplishments of this study will help the designers who deal with the hydrostatic- bearing compensated by constant restrictions to select the design parameters to approach the optimum condition.
SURVIVING CRISIS: INSIGHTS FROM NEW EXCAVATION AT KARPHI, 2008
Authors: Wallace Saro , Mylona Dimitra
Published: December 2012

Seventy years after its first investigation, Karphi (Karfi) on Crete was the subject of a new pilot excavation in 2008. The main aim was to provide the first up-to-date detailed contextual records for the site across a representative area, thus filling in interpretative gaps left by the original extensive excavation. This paper presents and analyses these records with the aim of investigating the likely complexity of social systems at one of the largest new communities founded in Crete after the collapse of Bronze Age statesc.1200bc. Recent research has tended to focus on small villages, or on sites which later developed into poleis, meaning that crisis-period remains are poorly preserved. Occupied only between the crisis horizon ofc.1200bcand an important nucleation of Cretan communities at large ‘proto-polis’ settlements occurring in the early tenth century, the large Karphi site offers insight into the special challenges of creating large, potentially diverse new communities in crisis circumstances. It has one of the most dramatic of the new settlement locations, on steep-sided peaks 1100 m above sea level in an area which had never previously been settled. The social and economic adjustments needed here were particularly sharp and urgent, and the paper examines the structures which enabled them, using preliminary analyses of bioarchaeological data from the new project to assist reconstruction of the economy. The site has had other, highly specialised uses in its history, on which the new excavation has thrown light. The results highlight not only the resonance of this landscape in ancient consciousness, but also the ways in which such resonance could be exploited, both in the socially volatile post-collapse period and in the context of enhanced social and economic complexity as polis states started to come into being. Finally, a first set of radiocarbon dates from the new excavation is presented and assessed with regard to the dating of the Cretan Bronze to Iron Age transition and its wider ramifications.
‘Id est, crux Christi’: tracing the Old English Motif of the Celestial Rood
Authors: Hawk Brandon W.
Published: December 2012

The celestial cross is a prominent motif in Old English texts, and, rather than deriving from a single specific source, the figure provides a case study with implications for understanding the variety of backgrounds that often contribute to Anglo-Saxon conceptions of specific literary images. Tracing the development of the motif from its early Christian origins to its role in Anglo-Saxon England reveals a persistent correlation to eschatology, the importance of the liturgy in its dissemination, and a complex matrix of associations that must be accounted for in considering the Old English settings in which the image exists. An examination of these literary settings further helps to interpret the ways in which Anglo-Saxon authors used this matrix of associations for the celestial cross in their conceptions of the Judgement Day.
A more permanent homeland: land tenure in Guthlac A
Authors: Clark Stephanie
Published: December 2012

To a greater extent than other saints' lives, Guthlac A is a poem about a land dispute. Through contextualizing the central ‘battle for the beorg’ within Anglo-Saxon practices of land tenure, this article shows that Guthlac A represents the spiritual conflict between Guthlac and the devils as a land dispute between unworthy tenants who have been given temporary tenure of the land and a warrior of God who is granted permanent tenure as his reward for faithful service. By portraying the devils' loss of the beorg and Guthlac's acquisition of it through the framework of Anglo-Saxon customs of land-holding, the poem dramatizes replacement doctrine, the teaching that the number of the saved would equal the number of fallen angels and replace them in the heavenly kingdom.
An archive of Yorùbá religious ephemera
Authors: Barber Karin , de Moraes Farias P.F.
Published: December 2012

An archive of ephemera seems almost a contradiction in terms. If archives come into being because governments and individuals preserve papers they consider to be worth keeping, then an archive should be a crystallisation of past and present values concerning texts. Most of Nigeria's archives are in fact that kind of crystallisation, whether they are local government records, newspaper collections, Arabic-language chronicles, or little-known collections of personal letters and diaries, preserved because the individuals concerned, and subsequently their heirs, had a sense of their value.
New Information Technologies: networks available or planned
Authors: de Roy Olivier Coeur
Published: December 2012

The Internet and other communication networks are development tools, quite as important as educational, agricultural and training programmes. Information, Information Technologies and data networks have (and have had) a fundamental role in the development of ‘northern societal and cultural environments’, though the Internet is still seen by some people in developed countries simply as a pastime, as a new multimedia entertainment providing nice graphics and images. In a society sated with information, the need for Information and Information Technologies are perhaps not always fully appreciated. The role of networks as valuable development tools may therefore be better understood in the African context. The purpose ofthis article, however, is not only to point out the importance of electronic communication networks such as the Internet in helping the processes of development in Africa, but also to offer readers of the Africa Bibliography an up-to-date guide to the extent and kinds of connectivity currently operating or being planned in African countries, and to some of the problems – political, financial, technical – that the new information technology faces today.
Cumulative Bibliography of African Studies: a guide
Authors: Hall David
Published: December 2012

The Cumulative Bibliography of African Studies was published in 5 quarto volumes by G.K. Hall of Boston for the International African Institute in 1973.
Mortality improvement by socio-economic circumstances in England (1982 to 2006)
Authors: Lu J. L. C. , Wong W. , Bajekal M.
Published: December 2012

Assessing longevity risk is crucial to the financial management of annuities and longevity-related financial instruments. Actuaries have been using socio-economic circumstances (SEC) of individuals estimated through postcodes, pension size and occupation to price annuities for prospective customers. Differences in mortality rates of people in different SEC have been discussed extensively but less is known about how their mortality rates have changed over time.

A lack of regular, consistent and credible mortality data for people in different SEC has hampered the study of historical mortality trends. This in turn has made forecasting a greater challenge. To address some of these data issues, we have obtained mortality and population data between 1981 and 2007 for England, divided into SEC quintiles (measured by the relative deprivation of the area of residence according to the Index of Multiple Deprivation (IMD) 2007). Using the data, we have analysed the mortality trends by SEC. These findings can provide insight into mortality improvement for people in different SEC. This can contribute to commercial decisions for annuity businesses, reinsurance and longevity swaps.
INEQUALITY IN A “POSTRACIAL” ERA
Authors: Gomberg-Muñoz Ruth
Published: December 2012

Over the past four decades, increasingly punitive and enforcement-oriented U.S. immigration policies have been legitimized by a rhetoric of criminality that stigmatizes Latino immigrant workers and intensifies their exploitation. Simultaneously, there has been a sevenfold increase in the prison population in the United States, in which African Americans are eight times more likely to be jailed than Whites (Western 2006, p. 3). In this paper, I draw on scholarship in history and sociology, as well as my own anthropological research, to develop the argument that criminal justice policies and immigration policies together disempower low-wage U.S. labor and maintain categorical racial inequalities in a “postracial” United States. First, I review the historical role of race in U.S. immigration policy, and I consider the evidence for systemic racism in immigration enforcement in the contemporary period. Second, I discuss criminal legislation in the neoliberal era and examine the ways in which criminal legislation and immigration policies together disempower large segments of the U.S. workforce, satisfying employer demands for low cost and pliant labor. Finally, I argue that a political focus on immigrant workers' “illegality” masks the role of the state in (re)defining the legal status of low-wage workers and veils the ways in which punitive policies maintain historical racial and class inequalities.
“JUAN CROW” IN THE NUEVO SOUTH?
Authors: Browne Irene , Odem Mary
Published: December 2012

In this paper, we apply Omi and Winant's theory of racial formation to understand how a new racial category of “Latino” is being created within Atlanta, a city firmly entrenched in a Black/White binary of race. Comparing Dominicans and Guatemalans in the Atlanta metro area, we show how two processes are “racializing” Latinos: 1) the homogenization of Latinos into a single “race” through state laws and policies and 2) the diversified understandings of and responses to race and racial categorization among Latinos based on their national origin and ethnicity and the specific Atlanta context. We argue that in moving beyond the Black/White binary, state laws that racialize Latinos create a two-dimensional category, with a homogenized “Latino” category as one axis and an illegal/legal distinction as the second axis. The meanings attached to “race” and the consequences that Latinos experience from racialization depend upon their perceived or actual legal status.
A POSTRACIAL SOCIETY OR A DIVERSITY PARADOX?
Authors: Lee Jennifer , Bean Frank D.
Published: December 2012

At the beginning of the twentieth century, Southern states decreed that one drop of African American blood made a multiracial individual Black, and even today, multiracial Blacks are typically perceived as being Black only, underscoring the enduring legacy and entrenchment of the one-drop rule of hypodescent. But how are Asians and Latinos with mixed ancestry perceived? Based on analyses of census data and in-depth interviews with interracial couples with children and multiracial adults, I find that the children of Asian-White and Latino-White couples are much less constrained by strict racial categories. Racial identification often shifts according to situation, and individuals can choose to identify along ethnic lines, as White, or as American. Like their Irish and Italian immigrant forerunners, the Asian and Latino ethnicities of these multiracial Americans are adopting the symbolic character of European, White ethnicity. We appear to be entering a new era of race relations in which the boundaries of Whiteness are beginning to expand to include new non-White groups such as Asians and Latinos, with multiracial Asians and Latinos at the head of the queue. However, even amidst the new racial and ethnic diversity, these processes continue to shut out African Americans, illustrating a pattern of “Black exceptionalism” and the emergence of a Black–non-Black divide in the twenty-first century.
UNSETTLING THE GEOGRAPHY OF OAKLAND'S WAR ON POVERTY
Authors: Herrera Juan C.
Published: December 2012

Historical studies of the War on Poverty have overwhelmingly focused on its consequences in African American communities. Many studies have grappled with how War on Poverty innovations co-opted a thriving African American social movement. This paper explores the impact of War on Poverty programs on the development of a political cadre of Mexican American grassroots leaders in Oakland, California. It investigates how coordinated 1960s protests by Mexican American organizations reveal Oakland's changing racial/ethnic conditions and shifting trends in the state's relationship to the urban poor. It demonstrates how a national shift to place-based solutions to poverty devolved the “problem of poverty” from the national to the local level and empowered a new set of actors—community-based organizations—in the fight against poverty. This essay argues that the devolution of federal responsibility for welfare provided the political and institutional opening for the rise of powerful Mexican American organizations whose goal was the recognition of a “Mexican American community” meriting government intervention. This essay also demonstrates how Mexican American organizations mobilized in relation to African American social movements and to geographies of poverty that were deemed exclusively Black.
RACE AND IMMIGRATION IN THE AMERICAN CITY: INTRODUCTION
Authors: Gutiérrez Ramón A.
Published: December 2012

This special section of the Du Bois Review had its origin in a conference on “Race and Immigration in the American City: New Perspectives on Twenty-First Century Intergroup Relations,” which the Center for the Study of Race, Politics, and Culture convened at the University of Chicago on May 27, 2011. The conference explored the nature of intergroup dynamics within multiracial and multiethnic contexts since 1964, when cities across the land were gradually transformed by the arrival of large numbers of new immigrants hailing from Asia and Latin America. Of particular interest were relations between African Americans and Latinos, two highly racialized groups who are often deemed in fierce competition with each other for poorly paid, unskilled jobs. The essays gathered here are the fruits of that conference.
STRENGTHENING THE WEAK STATE
Authors: Kato Daniel
Published: December 2012

This essay charts the development of the American state during the era when Southern lynchings prevailed. Contrary to the standard interpretation that depicts the American state as having lacked the administrative and legal capacity to protect the lives of Southern Blacks, it is a more pluralist conception of state weakness for which I argue, one that characterizes the American state's behavior regarding racial violence as the deliberate, calculated act of an active state choosing not to act. The state had always possessed legal authority to prosecute lynch mobs, but the key determinant was garnering the political will to enforce the law. Examples gleaned from the Ulysses S. Grant, Franklin Roosevelt (FDR), and Lyndon Johnson (LBJ) administrations illustrate the American government's political vacillation between acting and not acting. Examinations of two Supreme Court cases in 1966 highlight the political nature of federal rights enforcement. In light of the 1966 Supreme Court decisions inUnited States v. PriceandUnited States v. Guest, the Court appears never to have repudiated or stripped the federal government of all of its authority to engage in combating racial violence. Even though the Court clearly signaled during Reconstruction that it was not going to uphold claims of rights violations of Blacks in the South, it did so without ever making a substantive decision on whether it could. Sections 241 and 242 of Title 18 of the United States Code were, in effect, placed into suspended animation; it was only when there was a political will to reengage with federal rights enforcement that the Court resuscitated these laws. In the parlance of the weak state thesis, the American state did not lose its capacity to combat racial violence; rather it simply chose not to engage.
Former NSF assistant director Killeen reflects on geosciences and society
Authors: Showstack Randy
Published: December 2012

“This is prime time for the geosciences,” Tim Killeen, former assistant director for geosciences at the U.S. National Science Foundation (NSF GEO), told Eos during a recent exclusive interview. Killeen, who served at NSF from July 2008 until his term expired in June 2012, oversaw a number of new initiatives and an expansion of the geoscience directorate's annual funding portfolio from $752 million to about $880 million. NSF announced on 7 November that Roger Wakimoto, director of the National Center for Atmospheric Research, will start as the new geosciences assistant director in February 2013 (see related article, this page, and Eos, 93(47), 475, doi:10.1029/ 2012EO470004). During the broad‐ranging interview, Killeen reflected on the importance of the geosciences and their relationship to society. Killeen has been president of the Research Foundation for the State University of New York (RFSUNY) and SUNY vice chancellor for research since 9 July. He took the helm of RFSUNY after some personnel there “took advantage of lax oversight to cheat taxpayers,” according to New York State comptroller Thomas DiNapoli. Killeen, who was AGU president from 2006 to 2008, is responsible for the supervision and operation of RFSUNY, which supports about $1 billion in research at SUNY, an institution with 64 campuses and nearly 470,000 students.
Improving earthquake hazard assessments in Italy: An alternative to “Texas sharpshooting”
Authors: Peresan Antonella , Panza Giuliano F.
Published: December 2012

The 20 May 2012 M = 6.1 earthquake that struck the Emilia region of northern Italy illustrates a common problem afflicting earthquake hazard assessment. It occurred in an area classified as “low seismic hazard” based on the current national seismic hazard map (Gruppo di Lavoro, Redazione della mappa di pericolosità sismica, rapporto conclusivo, 2004, http://zonesismiche.mi.ingv.it/mappa_ps_apr04/italia.html) adopted in 2006. That revision of the seismic code was motivated by the 2002 M = 5.7 earthquake that struck S. Giuliano di Puglia in central Italy, also a previously classified low‐hazard area, resulting in damage and casualties. Previous code was updated in 1981–1984 after earlier maps missed the 1980 M = 6.5 Irpinia earthquake.
Training Partners in AAC in Culturally Diverse Families
Authors: Soto Gloria
Published: December 2012

This article focuses on culturally responsive AAC practice. Including parents in the process is essential to ensure that children with significant communication impairments receive the most appropriate communication tool and the most effective intervention strategies. Often, the roles expected or demanded from parents may conflict with the values, expectations, and abilities of many families, particularly those from culturally diverse backgrounds, which may contribute to low levels of participation. If clinicians are to work effectively with families from a range of different backgrounds, they need not only a greater understanding of culture and cultural values as they relate to AAC, but an increased awareness of the cultural influences affecting their own practices and recommendations. In this article, I describe the process of culturally responsive assessment and intervention and discuss the need for professionals to build opportunities for a truly reciprocal collaborative relationship with families.
Hydrogen diffusion in potassium intercalated graphite studied by quasielastic neutron scattering
Authors: Purewal Justin , Keith J. Brandon , Ahn Channing C. , Brown Craig M. , Tyagi Madhusudan , Fultz Brent
Published: December 2012

The graphite intercalation compound KC24 adsorbs hydrogen gas at low temperatures up to a maximum stoichiometry of KC24(H2)2, with a differential enthalpy of adsorption of approximately −9 kJ mol−1. The hydrogen molecules and potassium atoms form a two-dimensional condensed phase between the graphite layers. Steric barriers and strong adsorption potentials are expected to strongly hinder hydrogen diffusion within the host KC24 structure. In this study, self-diffusion in a KC24(H2)0.5 sample is measured experimentally by quasielastic neutron scattering and compared to values from molecular dynamics simulations. Self-diffusion coefficients are determined by fits of the experimental spectra to a honeycomb net diffusion model and found to agree well with the simulated values. The experimental H2 diffusion coefficients in KC24 vary from 3.6 × 10−9 m2 s−1 at 80 K to 8.5 × 10−9 m2 s−1 at 110 K. The measured diffusivities are roughly an order of magnitude lower that those observed on carbon adsorbents, but compare well with the rate of hydrogen self-diffusion in molecular sieve zeolites.
The method of convergence to calculate particles fluxes in X rays spectrometry techniques. Application in nuclear compounds
Authors: Figueroa C. , Nieva N. , Brizuela H. , Heluani S. P.
Published: December 2012

A method to calculate particle fluxes applicable in most of the spectroscopy techniques is described. Flux intensities of backscattered or absorbed electrons and emitted photons are calculated using a method of convergence to solve the invariant embedding equations that are used to describe the particle trajectories inside a solid sample. Our results are found to be helpful to carry out a procedure for quantitative characterization using instruments such as electron probe microanalyser or other probes. Examples of application to calculate the composition of ternary alloys are given and are compared with the same calculations using another procedure.
Electrical characterization and modelling of n–n Ge-Si heterojunctions with relatively low interface state densities
Authors: Peibst R. , Rugeramigabo E. P. , Hofmann K. R.
Published: December 2012

We investigated the electrical behavior of n–n Ge-Si isotype heterojunction diodes prepared by surfactant-mediated epitaxy of relaxed n-Ge layers on (100) n-Si substrates. Current-voltage characteristics were measured at different temperatures between 10 °C and 90 °C. The experimental results were interpreted with a new heterojunction model based on Shockley-Read-Hall kinetics for electron and hole capture/emission at the interface traps, which describes the bias dependent interface and semiconductor charges, the trap-mediated currents, and the thermionic electron transmission current. The modeled thermionic electron emission current was in excellent agreement with the experimental current-voltage characteristics in the whole temperature range for negative (≥−0.5 V) and positive (≤0.1 V) Ge biases. Trap-mediated currents were much smaller for reasonable trap capture cross sections σ ≤ 10−14cm2. From the experimental data, we extracted an electron barrier height of 0.59 eV at room temperature and an effective density of interface traps of only 5·1012cm−2eV−1 near the Si midgap. The charge carrier exchange between these traps with the Ge side was found to be much more efficient than with the Si side. The presence of a hole inversion layer at the interface proved to be essential for the interpretation of the heterojunction characteristics.
Analytical estimation of neutron yield in a micro gas-puff X pinch
Authors: Derzon M. S. , Galambos P. C. , Hagen E. C.
Published: December 2012

In this paper, we present the basic concepts for developing a micro x pinch as a small-scale neutron source. For compact sources, these concepts offer repetitive function at higher yields and pulsing rates than competing methods. The uniqueness of these concepts arises from the use of microelectronic technology to reduce the size of the target plasma and to efficiently heat the target gas. The use of repetitive microelectromechanical systems (MEMs) gas puff technology, as compared to cryogenic wires or solid targets (for the beam-target alternatives), has the potential to be robust and have a long lifetime because the plasma is not created from solid surfaces. The modeling suggests that a 50 J at the wall plug pulse could provide >105 tritium (DT) neutrons and 103 deuterium (DD) neutrons at temperatures of a few keV. At 1 kHz, this would be >108 and 106 neutrons per second, DT and DD, respectively, with a 250 μm anode-cathode gap. DT gas puff devices may provide >1012 neutrons/s operating at 1 kHz and requiring 100 kW. The MEMs approach offers potentially high pulse rates and yields.
Intermetallic compound formation at Cu-Al wire bond interface
Authors: Bae In-Tae , Young Jung Dae , Chen William T. , Du Yong
Published: December 2012

Intermetallic compound (IMC) formation and evolution at Cu-Al wire bond interface were studied using focused ion beam /scanning electron microscopy, transmission electron microscopy (TEM)/energy dispersive x-ray spectroscopy (EDS), nano beam electron diffraction (NBED) and structure factor (SF) calculation. It was found that discrete IMC patches were formed at the Cu/Al interface in as-packaged state and they grew toward Al pad after high temperature storage (HTS) environment at 150 °C. TEM/EDS and NBED results combined with SF calculation revealed the evidence of metastable θ′-CuAl2 IMC phase (tetragonal, space group: I4¯m2, a = 0.404 nm, c = 0.580 nm) formed at Cu/Al interfaces in both of the as-packaged and the post-HTS samples. Two feasible mechanisms for the formation of the metastable θ′-CuAl2 phase are discussed based on (1) non-equilibrium cooling of wire bond that is attributed to highly short bonding process time and (2) the epitaxial relationships between Cu and θ′-CuAl2, which can minimize lattice mismatch for θ′-CuAl2 to grow on Cu.
Growth of controllable ZnO film by atomic layer deposition technique via inductively coupled plasma treatment
Authors: Huang Hsin-Wei , Chang Wen-Chih , Lin Su-Jien , Chueh Yu-Lun
Published: December 2012

An inductively coupled plasma technique (ICP), namely, remote-plasma treatment was introduced to ionize the water molecules as the precursor for the deposition of ZnO film via the atomic layer deposition processes. Compared with the H2O gas as the precursor for the ALD growth, the ionized water molecules can provide a lesser energy to uniformly stabilize oxidization processes, resulting in a better film quality with a higher resistivity owing to less formation of intrinsic defects at a lower growth temperature. The relationship between resistivity and formation mechanisms have been discussed and investigated through analyses of atomic force microscopy, photonluminescence, and absorption spectra, respectively. Findings indicate that the steric hindrance of the ligands plays an important rule for the ALD-ZnO film sample with the ICP treatment while the limited number of bonding sites will be dominant for the ALD-ZnO film without the ICP treatment owing to decreasing of the reactive sites via the ligand-exchange reaction during the dissociation process. Finally, the enhanced aspect-ratio into the anodic aluminum oxide with the better improved uniform coating of ZnO layer after the ICP treatment was demonstrated, providing an important information for a promising application in electronics based on ZnO ALD films.
Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets
Authors: Tamagnone M. , Gómez-Díaz J. S. , Mosig J. R. , Perruisseau-Carrier J.
Published: December 2012

Resonant graphene antennas used as true interfaces between terahertz (THz) space waves and a source/detector are presented. It is shown that in addition to the high miniaturization related to the plasmonic nature of the resonance, graphene-based THz antenna favorably compare with typical metal implementations in terms of return loss and radiation efficiency. Graphene antennas will contribute to the development of miniature, efficient, and potentially transparent all-graphene THz transceivers for emerging communication and sensing application.
Surface spin-glass, large surface anisotropy, and depression of magnetocaloric effect in La0.8Ca0.2MnO3 nanoparticles
Authors: Xi S. B. , Lu W. J. , Wu H. Y. , Tong P. , Sun Y. P.
Published: December 2012

The surface magnetic behavior of La0.8Ca0.2MnO3 nanoparticles was investigated. We observed irreversibility in high magnetic field. The surface spin-glass behavior as well as the high-field irreversibility is suppressed by increasing particle size while the freezing temperature TF does not change with particle size. The enhanced coercivity has been observed in the particles and we attributed it to the large surface anisotropy. We have disclosed a clear relationship between the particle size, the thickness of the shell, and the saturation magnetization of the particles. The large reduction of the saturation magnetization of the samples is found to be induced by the increase of nonmagnetic surface large since the thickness of the spin-disordered surface layer increases with a decrease in the particle size. Due to the reduction of the magnetization, the magnetocaloric effect (MCE) has been reduced by the decreased particle size since the nonmagnetic surface contributes little to the MCE. Based on the core-shell structure, large relative cooling powers RCP(s) of 180 J/kg and 471 J/kg were predicted for a field change of 2.0 T and 4.5 T, respectively, in the small particles with thin spin-glass layer.
An investigation of the optical properties of disordered silicon nanowire mats
Authors: Bao Hua , Zhang Weixia , Chen Liangliang , Huang Haoxiang , Yang Chen , Ruan Xiulin
Published: December 2012

Optical reflectance spectra of three disordered silicon nanowire mats with average diameters of 40, 60, and 80 nm are investigated both experimentally and theoretically. The total hemispherical reflectance spectra from 200 to 1600 nm wavelength are first measured. All three samples exhibit reflectance about 15% to 20% within the ultraviolet band. As the wavelength becomes longer, the reflectance will first increase to around 50% and then decrease to below 20%. Such reflectance spectra are attributed to the combined effect of silicon dielectric function, the nanowire geometry, and the volume fraction of the mats. An analytical method based on Mie scattering theory and two-flux model is proposed to predict the reflectance spectra of the NW mats using only the physical quantities including dielectric function and structural parameters of the nanowire mats. The experimental reflectance spectra can be well reproduced by this method.
Conduction and material transport phenomena of degradation in electrically stressed ultra low-k dielectric before breakdown
Authors: Breuer T. , Kerst U. , Boit C. , Langer E. , Ruelke H. , Fissel A.
Published: December 2012

The electrical degradation of ultra low-k SiCOH dielectric before breakdown is investigated. A new technique to obtain information before breakdown has been developed to define stress conditions and observe degradation patterns before total destruction occurs. Electrical measurements and physical inspection in specifically designed test structures have been made to focus on intrinsic properties. A typical leakage current characteristic, voiding and tantalum transport have been observed. These observations have been interpreted by quantitatively adapting physical effects. This investigation provides a model that describes the observed phenomena in a qualitatively manner.
Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites
Authors: Baur Cary , DiMaio Jeffrey R. , McAllister Elliot , Hossini Reza , Wagener Earl , Ballato John , Priya Shashank , Ballato Arthur , Smith Dennis W.
Published: December 2012

The piezoelectric performance of polyvinylidene fluoride (PVDF) is shown to double through the controlled incorporation of carbon nanomaterial. Specifically, PVDF composites containing carbon fullerenes (C60) and single-walled carbon nanotubes (SWNT) are fabricated over a range of compositions and optimized for their Young's modulus, dielectric constant, and d31 piezoelectric coefficient. Thermally stimulated current measurements show a large increase in internal charge and polarization in the composites over pure PVDF. The electromechanical coupling coefficients (k31) at optimal loading levels are found to be 1.84 and 2 times greater than pure PVDF for the PVDF-C60 and PVDF-SWNT composites, respectively. Such property-enhanced nanocomposites could have significant benefit to electromechanical systems employed for structural sensing, energy scavenging, sonar, and biomedical imaging.