bluuebunny/crossref_metadata_2025 huggingface dataset:
Social networks and their impact on the earnings of Mexican Migrants
Authors: Amuedo-Dorantes Catalina , Mundra Kusum
Published: December 2007

We examine the impact of different types of social networks on the wages earned by unauthorized and legal Mexican migrants during their last U.S. trip. Familial ties raise unauthorized and legal migrants’ hourly wages by an average of 2.6% and 8%, respectively, and friendship ties increase their wages by 5.4% and 3.6%, correspondingly. Furthermore, family ties seem to comparatively favor legal migrants in terms of earnings, raising their wages by approximately 0.9% more than for similar unauthorized migrants. These results underscore the potentially important role of social networks in raising Mexican migrants’ earnings, particularly among unauthorized migrants. By increasing the returns to migration, social networks may provide a stimulus to continued emigration.
The seasonality of conception
Authors: Rizzi Ester Lucia , Dalla-Zuanna Gianpiero
Published: December 2007

Individual data on menstrual cycles of noncontracepting women living in Western countries were used in order to verify whether the biological seasonality of conception persists after sexual behavior is controlled for. Episodes of intercourse were recorded daily, and the time of ovulation was detected by a marker. We find that the seasonality of conception changes with woman’s age and frequency of episodes of sexual intercourse. In particular, for women aged 27–31 having only one act of intercourse during the six most fertile days of the menstrual cycle, the seasonality of fecundability is stronger. In this age group in the Northern Hemisphere, if seasonality of acts of sexual intercourse is controlled, the monthly distribution of probability of conception is bimodal, with two maxima (September and January) and two minima (December and March). When unobserved characteristics of the couples are considered, this seasonal pattern of conception persists.
The estimation of Unwanted Fertility
Authors: Casterline John B. , El-Zeini Laila O.
Published: December 2007

The estimation of unwanted fertility is a major objective of demographic surveys, including DHS surveys conducted in Asia, Africa, and Latin America. Levels and trends in unwanted fertility are important input to the formulation of population policy and the evaluation of family planning programs. Yet existing methods for estimating unwanted fertility are known to be defective, among other reasons because they rely on subjective data whose validity and reliability are questionable. In this article, we propose a new estimator of unwanted fertility—the “aggregate prospective estimator”—so-named because it depends on the stated preference for another child at the time of the survey, the fertility-desires item consistently shown to possess the highest validity and reliability. Under reasonable assumptions, the aggregate prospective estimator produces less biased estimates of unwanted fertility than the most widely used existing methods. The new estimator has the limitation of generating only aggregate-level estimates, but such estimates are the primary data for policy formulation and program evaluation. The new estimator is presented in this article, along with an evaluation of its underlying assumptions and its sensitivity to several sources of error. In an illustrative application to recent DHS data from six countries, the new estimator yields substantially higher estimates of unwanted fertility than existing methods in all six countries.
Family transitions in Young Adulthood
Authors: Schoen Robert , Landale Nancy S. , Daniels Kimberly
Published: December 2007

Using the first (1995) and third (2001–2002) waves of the Add Health survey, we examine women’s family transitions up to age 24. Only a third of all women marry, and a fifth of those marriages dissolve before age 24. Three out of eight women have a first birth, with a substantial majority of those births outside of marriage: 66% for whites, 96% for blacks, and 72% for Mexican Americans. Cohabitation is the predominant union form; 59% of women cohabit at least once by age 24. Most cohabitations are short lived, with approximately one in five resulting in a marriage. We summarize the family and relationship experience of women up to age 24 in terms of four categories, each accounting for roughly a quarter of all women. Category 1 has the women who remain single nonparents. Category 2 has the early marriers, women whose marriage is not preceded by a first birth. Category 3 has those who become single parents. Category 4 has the women who cohabit at least once, but who do not marry or have a birth by age 24. The strictly ordered transitions of the 1950s are long gone and have been replaced by a variety of paths to adulthood.
Putting people into place
Authors: Entwisle Barbara
Published: December 2007

Over the past two decades, there has been an explosion of empirical research on neighborhoods and health. However, although the data and approaches owe much to the early contributions of demographers and population scientists, this debt is largely unrecognized. Likewise, challenges posed in the early literature remain largely unanswered. I argue that just as demographers and population scientists were pioneers in the study of neighborhoods and health, they are uniquely poised to lead the field again. Putting people into place means explaining behavior and outcomes in relation to a potentially changing local context. A more dynamic conceptualization is needed that fully incorporates human agency, integrates multiple dimensions of local social and spatial context, develops the necessary longitudinal data, and implements appropriate tools. Diverse approaches with complementary strengths will help surmount the many analytic challenges to studying the dynamics of neighborhoods and health, including agent-based microsimulation models.
Postimmigration investments in Education: a Study of Immigrants in the Netherlands
Authors: Van Tubergen Frank , van De Werfhorst Herman
Published: December 2007

We use a unique data source to examine postimmigration investments in education among four immigrant groups in the Netherlands. We derive hypotheses from the Immigrant Human Capital Investment model (IHCI), which argues that immigrants’ investments are an outcome of settlement intentions, skill transferability, and opportunity costs. The multinomial and ordered logistic regression analyses show that educational investments are stronger among immigrants with higher premigration education, immigrants from former colonies, immigrants who migrated for family reasons, and immigrants who arrived in periods of high unemployment. These ndings generally support the IHCI model.
The impact of childhood mortality on Fertility in six rural Thanas of Bangladesh
Authors: Hossain Mian Bazle , Phillips James F. , Legrand Thomas K.
Published: December 2007

In this article, we examine the relationship between child mortality and subsequent fertility using prospective longitudinal data on births and childhood deaths occurring to nearly 8,000 Bangladeshi mothers observed over the 1982–1993 period, a time of rapid fertility decline. Generalized hazard-regression analyses are employed to assess the effect of infant and child mortality on the hazard of conception, with controls for birth order and maternal age and educational attainment. Results show that childhood mortality reduces the time to subsequent conception if the death occurs within a given interval, representing the combined effect of biological and volitional replacement. The time to conception is also reduced if a childhood death occurs during a prior birth interval, a finding that signifies an effect of volitional replacement of the child that died. Moreover, mortality effects in prior birth intervals are consistent with hypothesized insurance (or hoarding) effects. Interaction of replacement with elapsed time suggests that the volitional impact of child mortality increases as the demographic transition progresses. This volitional effect interacts with sex of index child. Investigation of higher-order interactions suggests that this gender-replacement effect has not changed over time.
The Effects of High School Feeder Networks on College Enrollment
Authors: Wolniak Gregory C , Engberg Mark E
Published: December 2007

This study examines the influence of networks established among high schools and colleges. Focusing on the college choice process, the authors analyzed data from the 2006 admissions and financial aid records at eight private, four-year colleges representing nearly 18,000 students. Results show that high school feeder networks have an important influence on students' college choice. However, the impact of and access to such networks varies according to student characteristics. The conclusion discusses implications for research and institutional policy.
Pedagogical Practices That Contribute to Social Justice Outcomes
Authors: Mayhew Matthew J , Fernández Sonia Deluca
Published: December 2007

The authors investigated the extent to which classroom pedagogical practices and disciplinary course focus contributed to understandings of social justice outcomes among 406 undergraduate students enrolled in five college courses. They found that gender, enrollment in Intergroup Dialogue, service-learning, Introduction to Sociology courses, and practices encouraging reflection, discussions about diversity, and diverse peer interactions contributed to students' social justice learning. The article concludes with a discussion of the findings' implications.
Nonresident Enrollment Demand in Public Higher Education: An Analysis at National, State, and Institutional Levels
Authors: Zhang Liang
Published: December 2007

This article estimates the standard demand equations for nonresident students using national, state, and institutional level data. The national-level analysis reveals a near-unitary price elasticity, but increases in nonresident tuition and fees do not decrease nonresident enrollment. Finally, results from the institutional level of analysis (preferred) indicate rather inelastic student responsiveness to changes in nonresident tuition and fees. On average, a 1% increase in nonresident tuition and fees at a public institution is associated with a 0.2% reduction in its nonresident enrollment. Furthermore, price elasticity is smaller at selective institutions than at less selective ones.
Stories of Success: Experiences of American Indian Students in a Peer-Mentoring Retention Program
Authors: Shotton Heather J , Oosahwe E. Star L , Cintrón Rosa
Published: December 2007

The postsecondary attrition rate for American Indian students is higher than of any other racial or ethnic group. It is therefore imperative to identify factors that encourage their persistence in higher education. Employing a phenomenological approach, this study explored the experiences of American Indian college students in a peer-mentoring retention program at one university. The findings revealed key elements in establishing a successful peer-mentoring relationship and confirmed that peer mentoring can be a vital component in American Indian student integration and academic success. These findings warrant further investigation into the characteristics of successful peer-mentoring programs using other American Indian populations.
Late sodic metasomatism evidences in bimodal volcanic rocks of the Acampamento Velho Alloformation, Neoproterozoic III, southern Brazil
Authors: Almeida Delia Del Pilar M. de , Pereira Vitor P. , Machado Adriane , Zerfass Henrique , Freitas Ricardo
Published: December 2007

A mineralogical study was carried out in mafic and felsic volcanic rocks of the Acampamento Velho Alloformation at Cerro do Bugio, Perau and Serra de Santa Bárbara areas (Camaquã Basin) in southern Brazil. The Acampamento Velho bimodal event consists of two associations: lower mafic at the base and upper felsic at the top. Plagioclase and alkali-feldspar were studied using an electronic microprobe, and magnetite, ilmenite, rutile, illite and alkali-feldspar were investigated through scanning electron microscopy. The rocks were affected by a process of late sodic autometasomatism. In mafic rocks, Ca-plagioclase was transformed to albite and pyroxenes were altered. In felsic rocks, sanidine was partially pseudomorphosed, generating heterogeneous alkali-feldspar. In this association, unstable Ti-rich magnetite was replaced by rutile and ilmenite. In mafic rocks, the crystallization sequence was: (1) Ti-rich magnetite (?), (2) pyroxene and Ca-plagioclase, (3) albite (alteration to Ca-plagioclase), (4) sericite, chlorite and calcite (alteration to pyroxene), and kaolinite (alteration to plagioclase/albite). In felsic rocks: (1) zircon, (2) Ti-rich magnetite, (3) sanidine, (4) quartz. The introduction of late Na-rich fluids, generated the formation of (5) heterogeneous alkali-feldspar, (6) ilmenite and rutile from the Ti-rich magnetite, (7) albite in the spherulites. Finally, alteration of sanidine, vitroclasts and pumice to (8) illite.
A comunicação não-verbal enquanto fator iatrogênico
Authors: Araújo Monica Martins Trovo de , Silva Maria Júlia Paes da , Puggina Ana Cláudia G.
Published: December 2007

O estudo teve como objetivo verificar se os enfermeiros identificam situações nas quais os aspectos não-verbais da comunicação interpessoal entre profissionais de saúde e pacientes constituem fator iatrogênico. Os dados foram coletados por meio de entrevista semi-estruturada com oito enfermeiros e analisados segundo a metodologia de análise de conteúdo. Do discurso dos profissionais emergiram três categorias, que evidenciam a percepção da iatrogenia, suas conseqüências e características e a interrelação entre a linguagem não-verbal e o cuidado.
Traffic soil compaction of an oxisol related to soybean development and yield
Authors: Beutler Amauri Nelson , Centurion José Frederico , Centurion Maria Aparecida Pessoa da Cruz , Freddi Onã da Silva , Sousa Neto Eurico Lucas de , Leonel Cristian Luarte , Silva Álvaro Pires da
Published: December 2007

Excessive traffic on the soil may affect soybean development. This research was carried out to evaluate soybean root development and grain yield under compacted soil, in an Oxisol. The following traffic treatments were used: T0 = no traffic; T1* = 1 passage of a 4 t tractor; and, T1, T2, T4 and T6, respectively for 1, 2, 4 and 6 passages of an 11 t tractor on the same location, each besides the other. After compaction, soybean [Glycine max cv. MG/BR 46 (Conquista)] was cultivated. The experiment was arranged in a completely randomized design, with six compaction levels and four replicates (plots of 9.0 m²). Undisturbed soil samples were collected in the layers 0.03-0.06, 0.08-0.11, 0.15-0.18 and 0.22-0.25 m, for physical analyses. Root analyses were performed at layers of 0.0-0.10, 0.10-0.15 and 0.20-0.25 m. Soil compaction decreased deep root development and did not affect root amount, but its distribution. Yield decreased at the penetration resistance of 2.33 MPa or higher, and soil bulk density of 1.51 Mg m-3 or higher.
Corrosion Performance of Welded CRA-Lined Pipes for Flowlines
Authors: Chen W-C. , Petersen C. W.
Published: December 2007

This paper presents the results of corrosion and mechanical testing of welded high-nickel, corrosion-resistant-alloy (CRA)-lined pipes manufactured using various lining processes. The corrosion resistance of CRA-lined pipes for use as a flowline material in sour service was evaluated. The effects of the manufacturing process, CRA lining material, and welding on the corrosion performance of CRA-lined pipes also were determined.
Perturbation Boundary Element Method for Heterogeneous Reservoirs: Part 2—Transient-Flow Problems
Authors: Sato Kozo , Horne Roland N.
Published: December 2007

This paper discusses the extension of the perturbation boundary element method (BEM) described in the companion paper (Part 1) to transient-flow problems with permeability and porosity variations. The perturbation BEM formulated in Laplace space is verified against simplified heterogeneous problems and is used to generate type curves for idealized heterogeneities. We observed that if the average property value in a drainage area was not much different from the near-well property value, heterogeneity had little effect on pressure responses.
Network Security Fundamentals
Authors: Graham Steven , Fu Xinwen , Lu Bin
Published: December 2007

Communication is at the heart of computer systems. Information stored at one location is moved to another location, combined with data from other sources, and processed to meet the needs of the users. Rarely can user commands or the information they access avoid traversing networks, which leakes the data and systems vulnerable to a variety of attacks. A malicious intruder might intercept, falsify, damage, or altogether prevent the networked communications. Network security has become one of the more critical issues challenging businesses and our daily life.

In this chapter, we introduce the fundamentals of network security. The chapter comprises six sections. In the first section, we introduce basic security concepts such as CIA (confidentiality, integrity, and availability). In the second section, we discuss basic cryptography, such as secret key cryptography, public key cryptography, and hash functions. In the third section, we introduce basic security services such as key management and authentication. In the fourth section, we discuss a variety of attacks such as sniffing, spoofing, and DDoS (Distributed Denial of Service) to give a big picture of the cruel world of cyberspace. In the fifth section, we introduce some security systems and protocols such as Kerberos, IPSec, Firewall, and VPN to combat those attacks. Finally, we give a brief overview of wireless network security such as WEP and WPA.
Program Transformation: What, How, and Why
Authors: Winter Victor L.
Published: December 2007

Transformationcan be viewed as a philosophy on how to achieve change. A rigorous treatment of transformation has its roots inequational reasoning—the idea that equals can be substituted for equals. This article explorestransformationas it applies to the manipulation of software.
Convex Optimization
Authors: Sapatnekar Sachin S.
Published: December 2007

Several practical problems in computer science and computer engineering may be framed as convex optimization problems. Unlike a general optimization formulation that may be trapped in a local minimum, necessitating hill‐climbing methods to crawl out of such a minimum, a convex optimization formulation has the attractive property that any local minimum is guaranteed to be a global minimum. This chapter presents an overview of the theory behind convex optimization and some illustrative examples of representative problems that are convex programs.
Very Large Databases
Authors: Garofalakis Minos , Polyzotis Neoklis
Published: December 2007

In this article, we provide an overview of date reduction and approximation methods for massive databases and discuss some of the issues that develop from different types of data, large data volumes, and applications‐specific requirements.
Granular Computing
Authors: Yao Yiyu , Zhong Ning
Published: December 2007

The central ideas and principles of the new paradigm of granular computing are the problem conceptualizations and problem solving using different levels of granularity. On the one hand, one can focus on a suitable level of relevant conceptualizations without considering irrelevant lower level details. On the other hand, one can change granularity at different stages. This article provides an introduction to granular computing as a way of thinking and a general method of problem solving that embraces a variety of concrete theories and methods.
Lighting
Authors: Křivánek Jaroslav , Pattanaik Sumanta
Published: December 2007

This article gives a short introduction to lighting simulation. First, we introduce the radiometric quantities describing light energy distribution in space. Using these quantities, we define the bidirectional reflection distribution function characterizing surface reflection properties, and we give various models of light sources used for lighting simulation. We then move on to give a survey of lighting simulation algorithms in current use. We start with the simplest direct lighting, identifying its weaknesses that lead us to global illumination. We give a mathematical foundation of the global illumination problem, the Rendering Equation. A number of approaches to solving this equation are then shortly described. Finally, we compare the state of the art in lighting simulation in industry and in the research community and give some ideas for prospective future work in the field.
Computational Complexity Theory
Authors: Allender Eric
Published: December 2007

This article is a brief overview of the field of computational complexity theory.
Level Set Methods
Authors: Yilmaz Alper
Published: December 2007

The shape of a real‐world object can be represented by a parametric or a nonparametric contour in the image plane. The parametric contour representation is referred to as an explicit representation, and is defined in the Lagrangian coordinate system. In this coordinate system, two different objects have two different representations stemming from the different sets of control points that define the object contours. The control points constitute the finite elements, which is a common formalism used to represent shapes in the Lagrangian coordinates. In contrast to the parametric Lagrangian representation, the nonparametric representation defines the object contour implicitly in the Eulerian coordinates, which remains constant for two different objects. The level set method is a nonparametric representation defined in the Eulerian coordinate system and is used commonly in the computer vision community to represent the shape of an object in an image.

The level set method has been introduced in the field of fluid dynamics by the seminal work of Osher and Sethian in 1988. After its introduction, it has been applied successfully in the fields of fluid mechanics, computational physics, computer graphics, and computer vision. In the level set representation, the value of each grid point (pixel) is set traditionally to the Euclidean distance between the grid point and the contour. Hence, moving the contour from one configuration to the other is achieved by changing the distance values in the grid points. During its motion, the contour can change its topology implicitly by splitting into two disjoint contours or by merging from two contours to one.

The implicit nature of the representation becomes essential to handle the topology changes for the case when an initial configuration is required to solve a time‐dependent problem. Upon initialization, the level set converges to a solution by re‐evaluating the values at the grid points iteratively. This iterative procedure is referred to as the contour evolution.
Solid Modeling
Authors: Hui K. C.
Published: December 2007

Solid modeling is the technique for representing and manipulating a complete description of physical objects. Valid representations of solid are developed base on a mathematical description of rigid object. A valid solid representation scheme provides sufficient information for geometric operations on objects, e.g. Boolean operations, collision detection. The description here introduces the Fundamental concepts in solid modeling are introduced. Characteristics of a solid representation scheme are discussed. Two popular solid representation schemes, the constructive solid geometry and the boundary representation schemes, are described. The fundamental algorithms for solid modeling, point membership classification, and Boolean operations, are also discussed. Validity of the boundary representation scheme, the Euler operators, as well as the Winged‐edge data structure for the implementation of boundary representation scheme are also presented.
Surface Deformation
Authors: Hui K. C.
Published: December 2007

Surface deformation is a fundamental tool for the construction and animation of three‐dimensional (3‐D) models. Deforming a surface requires adjusting the defining parameters in the representation of the surface or the use of deformation tools. This description gives an overview of the parameters that can be used for deforming different types of surfaces. Geometry‐based deformation tools, namely, free‐form deformation, axial deformation, and constraints‐based deformation, will be discussed. These tools allow objects to be deformed by manipulating a lattice of control vertices, an axial curve, or a set of constraints. Physics‐based deformation will also be discussed. Physics‐based deformation associates material properties to an object such that the deformation of objects can be performed according to physical laws. Physics‐based deformation provides an essential tool for generating motions of deformable objects for animation purposes.
Information Age
Authors: Eisner Howard
Published: December 2007

The Information Age is a period of time, or era, in which information itself, in its various forms, constitutes a key or dominant ingredient in our delivery of products and services. The Information Age began to emerge in a most serious manner about halfway through the twentieth century, when, for the first time, white collar workers started to outnumber blue collar employees. This newly born and growing Information Age was facilitated, in large measure, by

pre‐existing successes in telegraphy, telephony, radio, and television;

bringing large‐scale computers into our businesses, led by IBM;

the success of xerography and copying machines, notably by Xerox; and

the response to the challenge represented by the 1957 launch of Sputnik by the Russians.

All of the above provided initial fuel for the Information Age engine by proving the importance of information‐related technologies and demonstrating their economic value in the marketplace. Two additional and extremely significant sets of events included the refinement and market penetration of

the personal computer (PC) along with its resident applications, and

connectivity and the Internet.
Futility Analysis
Authors: Freidlin Boris
Published: December 2007

Most randomized clinical trials are designed to demonstrate benefit of experimental versus standard treatment. For ethical and economic reasons, it is important to stop a trial early for “futility” if there is no longer a reasonable chance that the experimental arm can be shown to be definitively better than the standard arm. Futility monitoring has become a widely accepted component of clinical trial methodology. We provide a review of commonly used futility procedures and discuss practical aspects of their implementation.
Bayesian Dose‐Finding Designs in Healthy Volunteers
Authors: Zhou Yinghui
Published: December 2007

In the majority of phase I clinical trials, experimental drugs are administered via predefined dose‐escalation schemes to healthy volunteers to explore the relationship between the dose administered and the primary responses of interest. The responses might be binary outcomes such as adverse events; quantitative summary measures concerning pharmacokinetics (PK), such as the average or maximum plasma concentration over time; or pharmacodynamic (PD), such as heart rate or blood pressure changes from baseline. Conventional dose‐escalation designs can take a long time to complete to investigate every available dose. Also, conventional statistical analyses are not accurate due to small sample sizes: 20 to 80 volunteers are typically used in phase I trials. Adaptive designs have been studied as they can potentially speed up dose‐escalation and have better properties in terms of avoidance of unsafe doses and accuracy of estimation when compared with conventional designs. This review of state‐of‐the‐art adaptive designs illustrates how such a design can be implemented and discusses some practical issues met during implementation.
Covariates
Authors: Sauerbrei Willi
Published: December 2007

The central role of covariates for several issues in clinical research and patient management is discussed. In clinical trials covariates are used to define the patient population, to allocate treatment in a randomized trial, to adjust the estimate of a treatment effect, and to define subgroups for the investigation of interactions. Furthermore, we will discuss the issue of categorization or determination of the functional relationship to describe the influence of a continuous covariate on an outcome of interest. Some issues of reporting and of the summary assessments of prognostic markers are discussed in the last section. (The issues of analyzing a prognostic marker study are discussed elsewhere.) To further increase and improve the use of covariate data of individual patients, it is important to have reliable measurements and to analyze the data and their interrelationships with the most suitable statistical approach. Often, this will require a close collaboration between clinicians and statisticians.
Biased‐Coin Randomization
Authors: Smith Mike D.
Published: December 2007

The biased coin randomisation is introduced as a procedure to minimize study bias whilst maintaining treatment balance throughout the trial. The range of biased coin randomizations are described for 2 and more than 2 treatment groups, and also for equal and unequal randomization. Biased coin randomizations are described which use both fixed and adaptive levels of coin ‘bias’. The well‐known urn model is described as a special representation of the biased coin randomization, and the link is discussed. Finally, the use of the biased coin randomization procedure for balance within covariate strata, and the application to response adaptive randomizations are described.
Clinical Trials to Support Prescription to Over‐the‐Counter Switches
Authors: Brass Eric P.
Published: December 2007

In contrast to prescription drugs, over‐the‐counter (OTC) drugs require the consumer to make decisions about the use of the drug without the aid of a health‐care professional. Clinical research studies designed to assess the ability of consumers to use the OTC drug label to guide their treatment with the drug are an essential element of OTC regulatory decision making. Label comprehension studies test the label's communication of key messages to consumers. Actual use studies elucidate consumer behaviors when using the proposed OTC drug in a simulated OTC environment. Examples of how these studies can be used to inform program development and decision making are illustrated by case studies.
Interfacial Strain: The Driving Force for Selective Orbital Occupancy in Manganite Thin Films
Authors: Abad L. , Laukhin V. , Valencia S. , Gaup A. , Gudat W. , Balcells L. , Martínez B.
Published: December 2007

Complex oxides with perovskite structure are the ideal arena to study a plethora of physical properties including superconductivity, ferromagnetism, ferroelectricity, piezoelectricity and more. Among them, transition metal oxides are especially relevant since they present large electronic correlations leading to a strong competition between lattice, charge, spin, and orbital degrees of freedom. In particular, manganese perovskites oxides exhibit half‐metallic character and colossal magnetoresistive response rendering them as the ideal materials to develop novel concepts of oxide‐electronic devices and for the study of fundamental physical interactions. Due to the close similarity between kinetic energy of charge carriers and Coulomb repulsion, tiny perturbations caused by small changes in temperature, magnetic or electric fields, strain and so forth may drastically modify the magnetic and transport properties of these materials. In particular clarifying the role of interfacial strain in manganite thin films is interesting not only for device applications but also for basic understanding of physical interactions. A better comprehension of such strongly correlated systems might lead to control the different degrees of freedom in a near future contributing to the development of the so called orbitronics, i.e. controlling and modifying at will the orbital orientation of the 3d levels in transition metals. Here we reveal the importance of interfacial strain in high quality epitaxial thin films of La2/3Ca1/3MnO3 (LCMO), grown on top of SrTiO3 (STO) and NdGaO3 (NGO) (001)‐oriented substrates. We show that in such systems interfacial strain due to lattice mismatch lifts the degeneracy of the eg and t2g orbitals close to the film/substrate interface inducing Jahn‐Teller like distortions and promoting selective orbital occupancy and the appearance of an orbital glass insulating state in an otherwise ferromagnetic metallic material. These results highlight the role of strain and identify it as a key parameter in orbital control.
Structural Evolution of Self‐Assembling Nanohybrid Thin Films from Functionalized Urea Precursors
Authors: Karatchevtseva I. , Cassidy D. J. , Wong Chi Man M. , Mitchell D. R. G. , Hanna J. V. , Carcel C. , Bied C. , Moreau J. J. E. , Bartlett J. R.
Published: December 2007

Hybrid organic‐inorganic thin films exhibiting patterned structuring on the nanometer scale have been prepared through the controlled hydrolysis‐condensation of enantiomerically pure chiral urea‐based silyl compounds. The thin films are obtained by spin‐coating of sols obtained via acid‐ or base‐catalyzed hydrolytic condensation of these molecular precursors. A self‐templating process is demonstrated via atomic force and transmission electron microscopy, showing the formation of nanometer size aggregates consisting of interconnected spherulates under acidic condition and of assembled fibers under basic conditions.
Intra‐community infanticide and forced copulation in spider monkeys: a multi‐site comparison between Cocha Cashu, Peru and Punta Laguna, Mexico
Authors: Gibson K. Nicole , Vick Laura G. , Palma Ana Cristina , Carrasco Farah M. , Taub David , Ramos‐Fernández Gabriel
Published: December 2007

We describe two cases of infanticide, two suspected infanticides, and a forced copulation by familiar resident males in two populations of wild spider monkeys (Ateles belzebuth chamek and A. geoffroyi yucatanensis). These are the first known infanticides and forced copulation in spider monkeys. Data were gathered from four neighboring communities of spider monkeys in Manu National Park at the Cocha Cashu Biological Station, Peru and two communities in the Otoch Ma'ax Yetel Kooh Reserve at Punta Laguna, Mexico, during intensive field studies of over 2,000 hr each. These are rare behaviors, but results suggest that mating history and sexual coercion are important in spider monkey social relationships. Am. J. Primatol. 70:485–489, 2008. © 2007 Wiley‐Liss, Inc.
Carbohydrate accumulation and utilization by oocytes of Rhodnius prolixus
Authors: Santos Rachel , Mariano Ana C. , Rosas‐Oliveira Rafael , Pascarelli Bernardo , Machado Ednildo A. , Meyer‐Fernandes José R. , Gondim Katia C.
Published: December 2007

The processes of accumulation and mobilization of carbohydrate stores in eggs of Rhodnius prolixus were analyzed. During oogenesis, the total amounts of glycogen, glucose, and trehalose increased with an accumulation of proteins, especially when oocytes grew from 1.0 to 1.5 mm in length. At 2.0 mm length, when oocytes were ready for oviposition, nutrient reserves did not increase appreciably and trehalose content decreased. Mating did not affect the final content of carbohydrates or proteins in oocytes of mated and virgin females. A trehalase activity was detected in follicles containing vitellogenic oocytes, 1.0 and 1.5 mm length, in both mated and virgin females. This activity was extremely low in chorionated, 2.0‐mm oocytes. After oviposition, glycogen content decreased in fertilized eggs, but not in unfertilized ones, and some was present in newly hatched nymphs. Glucose content remained constant in unfertilized eggs, but increased in fertilized ones, while total protein amount was constant in both groups after egg laying. Arch. Insect Biochem. Physiol. 2007. © 2007 Wiley‐Liss, Inc.
Coordination Features of a Hybrid Scorpionate/Phosphane Ligand Exemplified with Iridium
Authors: Camerano José A. , Casado Miguel A. , Ciriano Miguel A. , Tejel Cristina , Oro Luis A.
Published: December 2007

Although the pentacoordinated complex [Ir{(allyl)B(CH2PPh2)(pz)2}(cod)] (1; pz=pyrazolyl, cod=1,5‐cyclooctadiene), isolated from the reaction of [{Ir(μ‐Cl)(cod)}2] with [Li(tmen)][B(allyl)(CH2PPh2)‐ (pz)2] (tmen=N,N,N′,N′‐tetramethylethane‐1,2‐diamine), shows behavior similar to that of the related hydridotris(pyrazolyl)borate complex, the carbonyl derivatives behave in a quite different way. On carbonylation of 1, the metalmetal‐bonded complex [(Ir{(allyl)B(CH2PPh2)(pz)2}CO)2(μ‐CO)] (2) that results has a single ketonic carbonyl bridge. This bridging carbonyl is labile such that upon treatment of 2 with PMe3 the pentacoordinated IrI complex [Ir(CO){(pz)B(η2‐CH2CHCH2)(CH2PPh2)(pz)}(PMe3)] (3) was isolated. Complex 3 shows a unique fac coordination of the hybrid ligand with the allyl group η2‐bonded to the metal in the equatorial plane of a distorted trigonal bipyramid with one pyrazolate group remaining uncoordinated. This unusual feature can be rationalized on the basis of the electron‐rich nature of the metal center. The related complex [Ir(CO){(pz)B(η2‐CH2CHCH2)(CH2PPh2)(pz)}(PPh3)] (4) was found to exist in solution as a temperature‐dependent equilibrium between the cis‐pentacoordinated and trans square planar isomers with respect to the phosphorus donor atoms. Protonation of 3 with different acids is selective at the iridium center and gives the cationic hydrides [Ir{(allyl)B(CH2PPh2)(pz)2}(CO)H(PMe3)]X (X=BF4 (5), MeCO2 (6), and Cl (7)). Complex 7 further reacts with HCl to generate the unexpected product [Ir(CO)Cl{(Hpz)B(CH2PPh2)(pz)CH2CH(Me)}(PMe3)]Cl (9; Hpz=protonated pyrazolyl group) formed by the insertion of the hydride into the Ir(η2‐allyl) bond. In contrast, protonation of complex 4 with HCl stops at the hydrido complex [Ir{(allyl)B(CH2PPh2)(pz)2}(CO)H(PPh3)]Cl (8). X‐ray diffraction studies carried out on complexes 2, 3, and 9 show the versatility of the hybrid scorpionate ligand in its coordination.
A General Method for Constructing Optically Active Supramolecular Assemblies from Intrinsically Achiral Water‐Insoluble Free‐Base Porphyrins
Authors: Zhang Yiqun , Chen Penglei , Liu Minghua
Published: December 2007

We have developed a general method to construct optically active porphyrin supramolecular assemblies by using a simple air–water interfacial assembly process. The method involved the in situ diprotonation of the free‐base porphyrins at the air–water interface and subsequent assembly under compression. We showed that two intrinsically achiral water‐insoluble free‐base porphyrin derivatives, 2,3,7,8,12,13,17,18‐octaethyl‐21H,23H‐porphine (H2OEP) and 5,10,15,20‐tetra‐p‐tolyl‐21H,23H‐porphine (H2TPPMe), could be diprotonated when spread onto a 2.4 M hydrochloric acid solution surface, and the Langmuir–Schaefer (LS) films fabricated from the subphase exhibited strong circular dichroism (CD) absorption, whereas those fabricated from pure Milli‐Q water subphase did not. The experimental data suggested that the helical stacking of the achiral porphyrin building blocks was responsible for the supramolecular chirality of the assemblies. Interestingly, such a method was successfully applied to a series of other intrinsically achiral free‐base porphyrins such as 5,10,15,20‐tetrakis(4‐methoxyphenyl)‐21H,23H‐porphine (H2TPPOMe), 5,10,15,20‐tetraphenyl‐21H,23H‐porphine (H2TPP), 5,10,15,20‐tetrakis(4‐(allyloxy)phenyl)‐21H,23H‐porphine (H2TPPOA), and 5,10,15,20‐tetrakis(3,5‐dimethoxyphenyl)‐21H,23H‐porphine (H2TPPDOMe). A possible mechanism has been proposed. The method provides a facile way to obtain optically active porphyrin supramolecular assemblies by using intrinsically achiral water‐insoluble free‐base porphyrin derivatives.
In an Attempt to Provide a User's Guide to the Galaxy of Benzylidene, Alkoxybenzylidene, and Indenylidene Ruthenium Olefin Metathesis Catalysts
Authors: Bieniek Michał , Michrowska Anna , Usanov Dmitry L. , Grela Karol
Published: December 2007

The data reported in this paper demonstrate that great care must be taken when choosing an appropriate catalyst for a given metathesis reaction. First‐generation catalysts were found to be useful in the metathesis of sterically unhindered substrates. Second‐generation catalysts (under optimised conditions) showed good to excellent activities toward sterically hindered and electron‐withdrawing group (EWG)‐substituted alkenes that do not react using the first‐generation complexes. A strong temperature effect was noted on all of the reactions tested. Interestingly, attempts to force a reaction by increasing the catalyst loading were much less effective. Therefore, when possible, it is suggested that metathesis transformations should be carried out with a second‐generation catalyst at 70 °C in toluene. However, different second‐generation catalysts proved to be optimal for different applications and no single catalyst outperformed all others in all cases. Nevertheless, some empirical rules can be deduced from the model experiments, providing preliminary hints for the selection of the optimal catalysts.
Why Are Some ML2 Molecules (M: Ca, Sr, Ba; L: H, F, Cl, Br) Bent While Others Are Linear? Implications of the Pseudo Jahn—Teller Effects.
Authors: Garcia‐Fernandez Pablo , Bersuker Isaac B. , Boggs James E.
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Crystal Structures of Na1/2Ln1/2TiO3 (Ln: La, Eu, Tb).
Authors: Ranjan Rajeev , Senyshyn Anatoliy , Boysen Hans , Baehtz Carsten , Frey Friedrich
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Structural Study of a New NASICON‐Type Solid Solution: Li1‐xLax/3Zr2(PO4)3.
Authors: Barre M. , Crosnier‐Lopez M. P. , Le Berre F. , Suard E. , Fourquet J. L.
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Crystal Structure of [K([2.2]crypt)]2[HgGe9](dmf).
Authors: Boeddinghaus M. Bele , Hoffmann Stephan D. , Faessler Thomas F.
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Crystal Structure and Magnetic Properties of Two New Cobalt Selenite Halides: Co5(SeO3)4X2 (X: Cl, Br).
Authors: Becker Richard , Prester Mladen , Berger Helmuth , Lin Ping Hui , Johnsson Mats , Drobac Djuro , Zivkovic Ivica
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Practical Preparation of Diosphenols by Ring Opening of α,β‐Epoxyketones Catalyzed by Silica Gel Supported Acids.
Authors: Zhu Rui , Xing Lixin , Wang Xinyan , Cheng Chuanjie , Liu Bo , Hu Yuefei
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Intermolecular Hydroamination of Methylenecyclopropane Catalyzed by Group IV Metal Complexes.
Authors: Smolensky Elena , Kapon Moshe , Eisen Moris S.
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Simple One‐Pot Procedure for the Direct Conversion of Alcohols into Alkyl Nitriles Using TsIm.
Authors: Soltani Rad Mohammad Navid , Khalafi‐Nezhad Ali , Behrouz Somayeh , Faghihi Mohammad Ali
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Mimicry of Polyketide Synthases—Enantioselective 1,4‐Addition Reactions of Malonic Acid Half‐Thioesters to Nitroolefins.
Authors: Lubkoll Jana , Wennemers Helma
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Stereoselective Synthesis of α‐Allenols by Rhodium‐Catalyzed Reaction of Alkynyl Oxiranes with Arylboronic Acids.
Authors: Miura Tomoya , Shimada Masahiko , Ku Sung‐Yu , Tamai Tomohiro , Murakami Masahiro
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Simple Method for the Preparation of Symmetrical Alkyl and Aryl Disulfides with Alkyl Sulfonyl Halides in Nitrogenous Base.
Authors: Ali Firdous Imran , Hashmi Imran Ali , Siddiqui Bina S. , Rasheed Munawwer
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Insecticidal Evaluation of N‐tert‐Butyl‐N′‐thio [O‐(1‐methylthioethylimino)‐N′′‐methylcarbamate]‐N,N′‐diacylhydrazines.
Authors: Shang Jian , Liu Yuxiu , Huang Runqiu , Bi Fuchun , Wang Qingmin
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A General Copper‐Catalyzed Sulfonylation of Arylboronic Acids.
Authors: Kar Anirban , Sayyed Iliyas Ali , Lo Wei Fun , Kaiser Hanns Martin , Beller Matthias , Tse Man Kin
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
N‐Heterocyclic Carbene—Palladium Complexes as Efficient Catalysts for the Oxidative Carbonylation of Amines to Ureas.
Authors: Zheng Shuzhan , Peng Xingao , Liu Jianming , Sun Wei , Xia Chungu
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Asymmetric Induction in Darzens Condensation by Means of (R)‐5,5‐Dimethyl‐4‐phenyloxazolidin‐2‐one as an Effective Chiral Auxiliary.
Authors: Badrian Abed , Mamaghani Manouchehr , Tabatabaeian Khalil , Valizadeh Hassan
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
An Environmentally Friendly Electrochemical Method for Synthesis of Benzofuranoquinone Derivatives.
Authors: Davarani Saied Saeed Hosseiny , Shamsipur Mojtaba , Nematollahi Davood , Ramyar Somayyeh , Masoumi Leila
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Design and Synthesis of Hepatoselective, Pyrrole‐Based HMG‐CoA Reductase Inhibitors.
Authors: Pfefferkorn Jeffrey A. , et al. et al.
Published: December 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.