cssi/SciSciGPT-SciSciNet huggingface dataset:
Skull developmental modularity: a view from a single bone – or two

I review recent studies that connect development and evolution of skull bones in teleosts. Development uses genetic information to build a structured, modular phenotype, and since selection acts on the phenotype, developmental modularity may influence evolvability. Just how is a complex developing morphology spatially partitioned into modules? Here I briefly examine cellular, molecular genetic, and multivariate statistical approaches to the identification of developmental modules. Furthermore I review our evidence that developmental modularity provides evolutionarily labile regions within the skull and hence potentially biases evolutionary change in a positive manner. This view is rather different from early ones in the field of evolutionary developmental biology, in which developmental constraint due to patterns such as heterochronies were supposed to negatively impact evolution.
Abnormal Regional Cerebral Blood Flow in the Caudate Nucleus Among Fibromyalgia Patients and Non-Patients Is Associated with Insidious Symptom Onset

SUMMARYObjectives: Compare resting state regional cerebral blood flow [rCBF] in patients with fibromyalgia [FMS], non-patients with FMS, and healthy controls as a function of insidious or physically traumatic symptom onset.Methods: All subjects were women and included 21 FMS patients with insidious symptom onset; 11 FMS patients with physically traumatic onset; 13 residents recruited from the Alabama community with FMS of insidious onset who had not consulted a physician for pain in the past 10 years [non-patients]; and 29 residents recruited from the Alabama community without FMS or any other chronic pain syndromes or illnesses [healthy controls]. All subjects underwent single photon emission computed tomographic imaging of brain rCBF during resting conditions, pain threshold assessment, as well as lumbar puncture, and they completed standardized self-report measures of pain intensity, fatigue, and depression. Group differences on these assessments were evaluated by analysis of variance and the Least Sig...
Incomplete homogenization of 18 S ribosomal DNA coding regions in Arabidopsis thaliana

As a result of concerted evolution, coding regions of ribosomal DNA sequences are highly conserved within species and variation is generally thought to be limited to a few nucleotides. However, rDNA sequence variation has not been systematically examined in plant genomes, including that of the model plant Arabidopsis thaliana whose genome was the first to be sequenced. Both genomic and transcribed 18 S sequences were sampled and revealed that most deviation from the consensus sequence was limited to single nucleotide substitutions except for a variant with a 270 bp deletion from position 456 to 725 in Arabidopsis numbering. The deletion maps to the functionally important and highly conserved 530 loop or helix18 in the structure of E. coli 16 S. The expression of the deletion variant is tightly controlled during developmental growth stages. Transcripts were not detectable in young seedlings but could be amplified from RNA extracts of mature leaves, stems, flowers and roots of Arabidopsis thaliana ecotype Columbia. We also show polymorphism for the deletion variant among four Arabidopsis ecotypes examined. Despite a strong purifying selection that might be expected against functionally impaired rDNAs, the newly identified variant is maintained in the Arabidopsis genome. The expression of the variant and the polymorphism displayed by Arabidopsis ecotypes suggest a transition state in concerted evolution.
ATP ground- and transition-states of bacterial enhancer binding AAA+ ATPases support complex formation with their target protein, σ54.

Transcription initiation by the sigma54 form of bacterial RNA polymerase requires hydrolysis of ATP by an enhancer binding protein (EBP). We present SAS-based solution structures of the ATPase domain of the EBP NtrC1 from Aquifex aeolicus in different nucleotide states. Structures of apo protein and that bound to AMPPNP or ADP-BeF(x) (ground-state mimics), ADP-AlF(x) (a transition-state mimic), or ADP (product) show substantial changes in the position of the GAFTGA loops that contact polymerase, particularly upon conversion from the apo state to the ADP-BeF(x) state, and from the ADP-AlF(x) state to the ADP state. Binding of the ATP analogs stabilizes the oligomeric form of the ATPase and its binding to sigma54, with ADP-AlF(x) having the largest effect. These data indicate that ATP binding promotes a conformational change that stabilizes complexes between EBPs and sigma54, while subsequent hydrolysis and phosphate release drive the conformational change needed to open the polymerase/promoter complex.
World distribution of sutures — the sites of former oceans

Abstract Continental collision is an inevitable consequence of plate motion. We show that many mountain belts within continents are products of continental collision and suggest that this process produced all fold mountain belts that now lie within continents although the destructive effects of suturing have in some cases eliminated from preservation much of the evidence of operation of the Wilson cycle of ocean opening and closing. We review the distribution of sutures of Proterozoic and Phanerozoic age in all continents except Antarctica and conclude, from consideration of 57 major suture zones, that plate-tectonic processes have operated on the earth throughout the last 2.5 b.y. and that it is unnecessary to invoke the operation of non-uniformitarian ensialic mountain building processes to explain any ancient fold belts.
Study of material process compatibility for a hybrid tissue scaffold formation system

Research in the field of tissue engineering has led to the development of multiple manufacturing methods for tissue scaffolds, such as electrospinning, ink jet printing and pressure deposition. In order to create a hybrid tissue scaffold fabrication system, we have researched and tested the properties of materials used to make successful tissue scaffolds. Specifically, we examined process compatibility of Polycaprolactone (PCL) and alginate. The finding will be used to identify proper material compositions for the integration into the fabrication system and optimize the fabrication process.
Practical limits on muscle synergy identification by non-negative matrix factorization in systems with mechanical constraints.

Statistical decomposition, including non-negative matrix factorization (NMF), is a convenient tool for identifying patterns of structured variability within behavioral motor programs, but it is unclear how the resolved factors relate to actual neural structures. Factors can be extracted from a uniformly sampled, low-dimension command space. In practical application, the command space is limited, either to those activations that perform some task(s) successfully or to activations induced in response to specific perturbations. NMF was applied to muscle activation patterns synthesized from low dimensional, synergy-like control modules mimicking simple task performance or feedback activation from proprioceptive signals. In the task-constrained paradigm, the accuracy of control module recovery was highly dependent on the sampled volume of control space, such that sampling even 50 % of control space produced a substantial degradation in factor accuracy. In the feedback paradigm, NMF was not capable of extracting more than four control modules, even in a mechanical model with seven internal degrees of freedom. Reduced access to the low-dimensional control space imposed by physical constraints may result in substantial distortion of an existing low dimensional controller, such that neither the dimensionality nor the composition of the recovered/extracted factors match the original controller.
The Effect of Nativity, Ethnicity and Race on the Earnings of Cape Verdean Americans

This paper estimates the net effects of nativity, ethnicity and race on the earnings of Cape Verdean Americans, a small, Afro-European group who speak a Portuguese-based Creole. While in their homeland, most Cape Verdeans identify as mestico, but in America they are usually perceived as black. The data come from the 2000 US Census and the American Community Survey (2000–2007); Native Born Non-Hispanic Whites and African Americans serve as benchmarks. The results show that, controlling for pre-migration education, foreign birth is not a handicap; indeed, for women it is an advantage. Ethnicity too is never a handicap and occasionally an advantage. Race, on the other hand, penalizes males. Native born Cape Verdean men who identify as “Other”, “Black Other” or “Black” earn significantly less than NBNH Whites. On the other hand, regardless of racial identity, Native born Cape Verdean women earn at least as much as NBNH Whites. Finally, one subgroup of native born Cape Verdean men and women, those who identify racially as “Black”, earn slightly more than African Americans.
Beyond building block theory? A critique of Thomas Kuhn

Since the publication of The Structure of Scientific Revolutions, the writings of Thomas S. Kuhn have had a great impact on the way sociologists perceive developments within their discipline. This essay offers a critical review of the Kuhnian framework and questions the unreflective endorsement of this perspective. After a brief summary of the main points in Kuhn's approach, this paper argues that Kuhnian approaches preclude the possibility of an investigation of the historical relations and developments that mediate the production of scientific knowledge. Kuhn retains a reified view of science free from both sociohistorical influence and critical scholarship. Ideas still beget ideas, and knowledge gained through scientific investigation is still cumulative.
Robust neuro-identification of nonlinear plants in electric power systems with missing sensor measurements

Fault tolerant measurements are an essential requirement for system identification, control and protection. Measurements can be corrupted or interrupted due to sensor failure, broken or bad connections, bad communication, or malfunction of some hardware or software. This paper proposes a novel robust artificial neural network identifier (RANNI) by combining a sensor evaluation and (missing sensor) restoration scheme (SERS) and an ANN identifier (ANNI) in a cascading structure. This RANNI is able to provide continuous on-line identification of nonlinear plants when some crucial sensor measurements are unavailable. A static synchronous series compensator (SSSC) connected to a power system is used as a test system to examine the validity of the proposed model. Simulation studies are carried out with single and multiple phase current sensors missing; results show that the proposed RANNI continuously tracks the plant dynamics with good precision during the steady state, the small disturbance, the transient state after a large disturbance and the unbalanced three-phase operations. The proposed RANNI is readily applicable to other plant models in power systems.
Teaching geophysics in developing countries

It would be difficult to overestimate the need for a physical understanding of natural phenomena in developing countries. Education, in modern times, goes hand in hand with empirical and mechanical interpretations of the physical world, in contrast with more primitive, animistic ideas. Quite apart from basic cultural drives, people in their daily lives see the need to explain and reduce the hazards caused by floods, droughts, earthquakes, tsunamis, volcanic eruptions, and land deformations, which continue to devastate wide areas of various parts of the world. In addition, there are the obvious applications of geophysics to exploration for mineral resources, to oil prospecting, and to the development of geothermal energy.
Radioactive equilibrium in ancient marine sediments

Abstract Radioactive equilibrium in eight marine sedimentary formations has been studied by means of direct determinations of uranium, radium and thorium. Alpha-particle counting has also been carried out in order to cross-calibrate thick-source counting techniques. The maximum deviation from radioactive equilibrium that has been noted is 11 per cent—indicating that there is probably equilibrium in all the formations analyzed. Thick-source alpha-particle counting by means of a proportional counter or an ionization chamber leads to high results when the samples contain less than about 10 p.p.m. of uranium. For samples having a higher content of uranium the results are in excellent agreement with each other and with those obtained by direct analytical techniques. The thorium contents that have been obtained correspond well to the average values reported in the literature. The uranium content of marine sediments may be appreciably higher than the average values that have been reported for sedimentary rocks. Data show that there is up to fourteen times the percentage of uranium as of thorium in the formations studied and that the percentage of thorium never exceeds that of uranium. While the proximity of a depositional environment to a land mass may influence the concentration of uranium in a marine sediment, this is not true with thorium.
Biochemical analysis of pleiotropy in Dictyostelium.

Abstract The patterns of accumulation of five developmentally regulated enzymes were determined in four aggregateless mutant strains of Dictyostelium . Previous analyses of these strains had predicted that they should not accumulate these markers. The results are consistent with the concept that a linear dependent pathway controls the temporal expression of development in this system.
On combining information-theoretic and cryptographic approaches to network coding security against the pollution attack

In this paper we consider the pollution attack in network coded systems where network nodes are computationally limited. We consider the combined use of cryptographic signature based security and information theoretic network error correction and propose a fountain-like network error correction code construction suitable for this purpose.
Nuclear proteins that interact with the β maj globin promoter start to accumulate in MEL cells within 12 hours of induction and RNA copies of the promoter successfully compete their binding in vitro

The induction of differentiation in mouse erythroleukemia (MEL) cells by dimethylosulfoxide (DMSO) is characterized by increased transcription of globin genes. We have determined that DMSO treated cells increase the levels of nuclear factors capable of overall interactions with the βmaj globin promoter during the initial 24 h post induction, as measured by gel mobility analysis. Two unprocessed βmaj globin mRNA precursors, which are present in MEL cell nuclei early in differentiation, were previously shown to contain the 5′ promoter flanking region, and thereby provided the nucleus with a pool of regulatory sequences in multiple RNA copies. We have studied the effect of RNA copies of the promoter region on binding interactions between DNA sequences of the βmaj globin promoter and nuclear factors that interact with these sequences. The promoter region RNA transcripts competed effectively for DNA binding proteins in vitro, while the antisense RNA from the same region did not. The most pronounced competition was observed with proteins from 12 h after DMSO induction, when the concentration of the DNA binding proteins was still increasing. Since the ‘upstream’ transcripts predominate at 12 h after DMSO induction, these results indicate that the promoter region transcripts may influence the equilibrium of binding between the βmaj globin promoter an the nuclear factors that bind to this region during DMSO induction.
Theoretical developments on the causes of ionospheric outflow

Abstract It is now well known that there is a substantial outflow of ionospheric plasma from the terrestrial ionosphere at high latitudes. The outflow consists of light thermal ions (H+, He+) as well as both light and heavy energized ions (H+, He+, O+, N+, NO+, O2+, N2+). The thermal ion outflows tend to be associated with the classical polar wind, while the energized ions are probably associated with either auroral energization processes or nonclassical polar wind processes. Part of the problem with identifying the exact cause of a given outflow relates to the fact that the ionosphere continuously convects into and out of the various high-latitude regions (sunlight, cusp, polar cap, nocturnal oval) and the time-constant for outflow is comparable to the convection time. Therefore, it is difficult to separate and quantify the possible outflow mechanisms. Some of these mechanisms are as follows. In sunlit regions, the photoelectrons can heat the thermal electrons and the elevated electron temperature acts to increase the polar wind outflow rate. At high altitudes, the escaping photoelectrons can also accelerate the polar wind as they drag the thermal ions with them. In the cusp and auroral oval, the precipitating magnetospheric electrons can heat the thermal electrons in a manner similar to the photoelectrons. Also, energized ions, in the form of beams and conics, can be created in association with field-aligned auroral currents and potential structures. The cusp ion beams and conics that have been convected into the polar cap can destabilize the polar wind when they pass through it at high altitudes, thereby transferring energy to the thermal ions. Additional energization mechanisms in the polar cap include Joule heating, hot magnetospheric electrons and ions, electromagnetic wave turbulence, and centrifugal acceleration.Some of these causes of ionospheric outflow will be briefly reviewed, with the emphasis on the recent simulations of polar wind dynamics in convecting flux tubes of plasma.
A simple, versatile feeder layer system for Brassica oleracea protoplast culture

Protoplasts from cauliflower (Brassica oleracea ssp. botrytis) and broccoli (ssp. italica) leaves and hypocotyls were successfully cultured on membrane filters over a feeder layer of cells from a B. campestris suspension culture. Cells from rice, tomato and tobacco suspensions were not as effective as the B. campestris cells. Plants were recovered from protoplasts of previously recalcitrant Brassica genotypes. Protoplasts cultured in low numbers (10-100) on the feeder layer divided and formed colonies capable of plant regeneration, as did fused protoplasts.
Liquidity Crisis: Zygmunt Bauman and the Incredible Lightness of Modernity

After having promoted and then tacitly abandoned the rhetoric of postmodernism, Zygmunt Bauman settled on the metaphor of a modernity that was growing more ‘liquid’ and ‘lighter’ than before. This essay explores the strengths and weaknesses of these metaphors, and attempts to contextualize Bauman’s insights in what has been called by the historian Yuri Slezkine the ‘Mercurian’ culture of diasporic Jewish life.
Monte Carlo analysis of short-range order in nitrogen-strengthened FeNiCrN austenitic alloys

Abstract A Monte Carlo simulation model which uses thermochemical experimental data to predict short-range atomic order in face-centered-cubic (f.c.c.), solid solution alloys of Fe containing both substitutional and interstitial solute elements is described by reference to the ordering of an FeNiCrN alloy. The interaction energies between pairs of atoms and between N and an interstitial vacancy are evaluated by matching the molar Gibbs free energy, predicted by a quasichemical model, to that deduced from thermochemical data. These are then used in a Monte Carlo simulation to determine the equilibrium short-range order, defined by the distribution of Ni, Cr and N atoms among the octahedral cells of the metal lattice. Applying the model to two Fe40Ni15Cr alloys—one with zero and the other with 0.25 wt.% N—at 1273 and 298 K revealed that, at the higher temperature, the distribution of the Ni and Cr atoms in the N-free alloy is nearly random but, in the alloy containing 0.25 wt.% N, there is appreciable short-range order involving both the metal and N atoms. Decreasing the temperature to 298 K increases the order in both alloys. The implication of the short-range order and N apportionment for the deformation mechanism in FeNiCrN f.c.c. alloys is discussed.
PackBot: A versatile platform for military robotics

The iRobot PackBot is a combat-tested, man-portable UGV that has been deployed in Afghanistan and Iraq. The PackBot is also a versatile platform for mobile robotics research and development that supports a wide range of payloads suitable for many different mission types. In this paper, we describe four R&D projects that developed experimental payloads and software using the PackBot platform. CHARS was a rapid development project to develop a chemical/radiation sensor for the PackBot. We developed the CHARS payload in six weeks and deployed it to Iraq to search for chemical and nuclear weapons. Griffon was a research project to develop a flying PackBot that combined the capabilities of a UGV and a UAV. We developed a Griffon prototype equipped with a steerable parafoil and gasoline-powered motor, and we completed successful flight tests including remote-controlled launch, ascent, cruising, descent, and landing. Valkyrie is an ongoing research and development project to develop a PackBot payload that will assist medics in retrieving casualties from the battlefield. Wayfarer is an applied research project to develop autonomous urban navigation capabilities for the PackBot using laser, stereo vision, GPS, and INS sensors.
Choice of nest site protects army ant colonies from environmental extremes in tropical montane forest

Unlike most social insects, Eciton burchellii army ants cannot thermoregulate through nest construction. Instead, army ants thermoregulate behaviorally by creating a living nest (bivouac), shifting its position and structure, and potentially through nest site selection. We hypothesized that bivouac site selection is critical to E. burchellii colony survival. We predicted elevation above sea level, with associated variation in local abiotic environments, would affect bivouac site selection by E. burchellii colonies. We also expected nest sites to buffer against ambient variation in abiotic conditions. We recorded bivouac site choice by E. burchellii colonies at sites ranging from lowland wet forests to montane forests and reviewed previously published data. We measured microclimatic variables associated with nest sites in high-elevation montane forests: temperature, relative humidity, and light levels. Bivouac site selection varied with elevation: as elevation increased, fewer bivouac sites were exposed, more were underground, and fewer were elevated (in trees). High-elevation bivouac sites moderated diurnal temperature variation and had higher relative humidity levels and lower light levels than ambient conditions. The buffering of ambient temperature and humidity decreased with elevation in montane forests, suggesting that abiotic extremes in bivouac sites at the highest elevations may contribute to the upper elevational range limits of E. burchellii.
Client-Side Relevance Feedback Approach for Image Retrieval in Mobile Environment

During the last decade, high quality i.e. over 1 megapixel built-in cameras have become standard features of handheld devices. Users can take high-resolution pictures and share with friends via the internet. At the same time, the demand of multimedia information retrieval using those pictures on mobile devices has become an urgent problem to solve, and therefore attracts attention. A relevance feedback information retrieval process includes several rounds of query refinement, which incurs exchange of images between the mobile device and the server. With limited wireless bandwidth, this process can incur substantial delay, making the system unfriendly to use. This issue is addressed by considering a Client-side Relevance Feedback CRF technique. In the CRF system, Relevance Feedback RF is done on client side along. Mobile devices' battery power is saved from exchanging images between server and client and system response is instantaneous, which significantly enhances system usability. Furthermore, because the server is not involved in RF processing, it is able to support more users simultaneously. The experiment indicates that the system outperforms the traditional server-client relevance feedback systems on the aspects of system response time, mobile battery power saving, and retrieval result.
Mechanism of Malathion and Parathion Resistance in the Two-Spotted Spider Mite, Tetranychus urticae

Comparative studies on the breakdown activities in organophosphate-resistant and -susceptible spider mite, Tetranychus urticae Koch, strains, against radioactive malation and parathion and non-radioactive malaoxon and para-oxon revealed that the resistant Blauvelt strain had a superior ability to detoxify malathion, parathion, and malaoxon as compared with the susceptible Niagara strain. In the case of malathion breakdown, the highest interstrain difference was found in the amount of carboxyesterase products, but a substantial difference in the phosphatase activity was also observed. These results were in accordance with the experiments in vivo with radioactive malathion and parathion. A second OP-resistant spider mite strain, characterized by another protection mechanism, also showed a high rate of malathion and parathion breakdown. The total uptake of malathion by the Blauvelt strain did not significantly differ from that by the Niagara strain. The rate of ChE inhibition in vivo in Niagara mites was much higher than in Blauvelt mites. Furthermore, homogenates of the Blauvelt strain were found to hydrolyse β -naphthyl benzoate at a higher rate than Niagara homogenates. The unique features of the malathion-resistance in the Blauvelt strain were compared with data already published on malathion-resistance in mosquitoes and house flies ( Musca domestica L.).
Recognition between random heteropolymers and multifunctional disordered surfaces

Abstract Multifunctionality and aperiodicity are two generic features that nature employs for pattern recognition. Can these features also be exploited such that similar behavior is exhibited by abiotic systems? We find that random heteropolymers, a class of synthetic polymers that embody multifunctionality and disorder, can recognize multifunctional disordered surfaces when the statistics characterizing the sequence and surface site distributions are related in a particular way. Some implications of this new notion of recognition due to statistical pattern matching for viral inhibition and chromatography are discussed.
Markets, markets everywhere? Understanding the Cuban anomaly.

Abstract Cuba has made exceptionally little use of markets compared with other centrally planned economies. Only in the 1970s did the Cubans begin to experiment with a state-controlled, parallel market and in 1980 with a free peasant market. Six years into the experiment, this market was closed, as it produced tensions common to other socialist experiences with market mechanisms: high prices, growing income and consumption inequality, and the illegal redirection of resources from the planned to market sphere. The free market was replaced with a more limited market mechanism, an expanded parallel market in both agricultural procurement and food distribution, considered more compatible with the Cuban commitment to egalitarianism.
Sports Medicine and Athletic Training in the 21st Century: Bridging the Gap Between Research and Clinical Practice

Sport and recreational activity is a vital part of today's society, and athletic training researchers are playing an important role in gaining a better understanding of how to promote safe and healthy participation for athletes of all ages. This article aims to illustrate the importance of research to prevent and effectively treat sport and recreational injuries. Increased physical activity among Americans is helping to combat chronic diseases such as obesity and diabetes, but injuries related to increased activity are on the rise. We must be responsible in our approach to promoting physical activity and participation in sport, while minimizing risk of injury. Athletic training researchers and colleagues from other disciplines within kinesiology, allied health sciences, and medicine must work collaboratively to identify predispositions to athletic injuries and illnesses. They must further conduct prospective studies that will help clinicians better manage these injuries and prevent their recurrence. This ...
Simultaneous Soft Pulses Applied at Nearby Frequencies

Abstract The rotation of a spin subject to an on-resonance soft pulse and simultaneously to a soft pulse at a nearby frequency may strongly deviate from the desired rotation expected for a single on-resonance pulse. The deviation is the result of transient frequency shifts of the spin caused by the off-resonance irradiation. We show that the resulting error can be corrected by shifting the frequency of the on-resonance pulse in such a way that it tracks the shift of the spin frequency. Experimentally, the effectiveness of this simple and intuitive method is demonstrated for simultaneous inversions at nearby frequencies in the case of both coupled and uncoupled spins. Simulations predict that the correction technique is effective for arbitrary pulse shapes and tip angles and is particularly useful when the frequency window of the shaped pulse is two to eight times the frequency separation between the chemical shifts of the two spins.
Digital magnetic recording systems

An input-output characterization for a digital magnetic recording system is presented. The most common modulation and coding techniques used in current products are surveyed. Some techniques for signal processing in magnetic recording are then discussed. The author concludes with a brief introduction to signal processing for arrays of magnetic disk drives. >
Next steps in understanding the multilevel determinants of health

This commentary briefly summarises past work that has used multilevel analysis to investigate the multilevel determinants of health and outlines possible new directions in this area. Topics discussed include the need to (1) examine contexts other than neighbourhoods; (2) improve measurement of group-level constructs; (3) apply techniques more appropriate for causal inference from observational data; (4) analyse data from "natural experiments" involving exogenous variations in contextual characteristics; (5) examine dependencies between groups (such as spatial dependencies) more broadly and allow for reciprocal relations between individuals and contexts; and (6) contrast multilevel statistical models (or regression models generally) and complex systems models in the study of multilevel effects.
Comparative Federalism in Africa: Implications for Theory

Recent years have seen major advances in the comparative study of federalism around the world. Improvements in our understandings of federalism have come from studies ranging from North America to European cases, and across the developing world, with a particular emphasis on Latin America and emerging Asia (Diaz-Cayeros 2006; Gibson 2004; Rodden 2006; Montinola, Qian, and Weingast 1995; Wibbels 2005). At the same time, there is a growing literature on the decentralization of power in Africa, as countries from Senegal to Kenya to Mozambique have undertaken processes to elect subnational governments (SNGs), often at the regional or district level as well as the local level, and ensure some degree of expenditure responsibility and fiscal resources for these. Nuanced analyses of these processes have emerged from studies that treat distinct countries, historical time periods, and public service sectors (cf. Boone 2003; Fessha and Kirkby 2008; Ribot 2002; Olowu and Wunsch, eds. 2004; inter alia). Surprisingly, however, there has been little systematic comparison of federalism in Africa. While a robust literature treats each of Africa's main federal countries in isolation, scholars have barely begun to leverage these cases comparatively to examine what federalism has to say about African politics or what African politics can contribute to the federalism literature. Some efforts have been made - often in edited volumes - to offer comparative glances by examining individual cases in detail and then engaging in comparative checking or using shadow cases (Turton, ed. 2006; Gana and Egwu, eds. 2002, inter alia). Yet structured comparison between Africa's main federal polities is rare. This paper begins to address this shortcoming by offering a preliminary structured comparison of the three countries - Ethiopia, Nigeria, and South Africa - where federalism can be said to exist as a stable institutional set.
Building Blocks for Young Children's Mathematical Development

This article describes the design principles behind a set of research-based software microworlds included in the Building Blocks program, a PreK to grade 2 software-based mathematics curriculum. Building Blocks’ approach is finding the mathematics in, and developing mathematics from, children’s activity. The materials are designed to help children extend and mathematize their everyday activities, from building blocks to art to songs and stories to puzzles. The 9-step design process model that defines what we mean by “research-based” is described and illustrated.
Looking at what you see, a coeliac face.

Coeliac disease is common worldwide. It is estimated to occur in about 1% of the US population [1]. While the rate of diagnosis is increasing [2], by far the majority of those with coeliac disease are currently undiagnosed. There are multiple reasons for the low rate of diagnosis; these include lack of awareness of the more subtle presentations of coeliac Screening studies from the United Kingdom have demonstrated the prevalence of the disease to be 1% of both sevenyear-old children and adults, suggesting that the disease starts in childhood and is present in adulthood when it may be manifested [9,19]. Along these lines, Finizio et al. (in this issue) of the journal describe the ‘coeliac face’ [20]. They describe dis-
Alternating Minimization Algorithms: From Blahut-Arimoto to Expectation-Maximization

In his doctoral thesis and in a prize-winning paper in the IEEE Transactions on Information Theory, R.E. Blahut described two computational algorithms that are important in information theory. The first, which was also described by Arimoto, computes channel capacity and the distribution that achieves it. The second computes the rate-distortion function and distributions that achieve it. Blahut derived these algorithms as alternating maximization and minimization algorithms. Two closely related algorithms in estimation theory are the expectation-maximization algorithm and the generalized iterative scaling algorithm, each of which can be written as alternating minimization algorithms. Algorithmic and historical connections between these four algorithms are explored.
Reviewing the SEC’s Review Process: 10-K Comment Letters and the Cost of Remediation

Securities and Exchange Commission (SEC) comment letters provide independent and timely feedback on the clarity of disclosures and on the extent to which filings comply with Generally Accepted Accounting Principles and SEC reporting regulations. We investigate factors that affect the probability of receiving a 10-K comment letter, the extent of comments received, and the cost of remediation. We find that in addition to factors explicitly stated to increase SEC scrutiny in Section 408 of the Sarbanes-Oxley Act, low profitability, high complexity, engaging a small audit firm, and weaknesses in governance are positively associated with the receipt of a comment letter, the extent of comments, and the cost of remediation. The probability that the comment letter results in a restatement is higher for smaller companies and for companies engaging a small audit firm. We also provide evidence that comments relating to accounting issues result in higher remediation costs, largely due to the additional time required to resolve comments relating to classification issues and fair value issues. Our findings should be of interest to stakeholders who use SEC comment letters to assess disclosure quality and reporting compliance, and to managers and other stakeholders impacted by costs associated with the SEC’s review process.
Serotonin-1A receptor activity and expression modulate adolescent anabolic/androgenic steroid-induced aggression in hamsters

Repeated high dose (5.0 mg/kg) anabolic/androgenic steroid exposure during adolescence stimulates offensive aggression in male Syrian hamsters. These studies examined whether anabolic/androgenic steroid-induced aggression was regulated by the activity and expression of serotonin (5HT) type-1A receptors. In a first experiment, adolescent male hamsters were treated with a mixture of anabolic/androgenic steroids and then scored for offensive aggression in the absence or presence of the selective 5HT1A receptor agonist R(+)-8-OH-DPAT (0.1-0.6 mg/kg). Adolescent anabolic/androgenic steroid-treated hamsters displayed high levels of offensive aggression that could be reversed by enhancing the activity of 5HT1A receptors. The agonist R(+)-8-OH-DPAT dose-dependently reduced the steroid-induced aggressive response, with significant reductions in aggression observed at 0.1-0.3 mg/kg. In a second set of experiments, adolescent hamsters were administered anabolic/androgenic steroids or vehicle and then examined for 5HT1A receptor localization and expression in regions of the brain important for aggression control. Hamsters treated with anabolic/androgenic steroids showed significant decreases in 5HT1A receptor-immunoreactive staining and protein levels in the anterior hypothalamus (i.e., a brain region central to the control of offensive aggression in hamsters) with no concomitant decrease in the number of 5HT1A receptor-expressing neurons. Together, these data support a role for site-specific down-regulation of 5HT1A receptor activity in adolescent anabolic/androgenic steroid-induced aggression.
High resolution electron microscope study of lattice images in biological apatites.

SUMMARY Lattice (Fourier) images of crystallites in human bone and teeth, and calcified atherosclerotic plaque were studied using high resolution transmission electron microscope techniques. The lattice images observed in the normal and diseased calcified tissue were compared with the images of synthetic hydroxyapatite crystallites.
The neural bases of cooperation and competition: an fMRI investigation

competition stances resulted in activation of a common frontoparietal network subserving executive functions, as well as the anterior insula, involved in autonomic arousal. Moreover, distinct regions were found to be selectively associated with cooperation and competition, notably the orbitofrontal cortex in the former and the inferior parietal and medial prefrontal cortices in the latter. This pattern reflects the different mental frameworks implicated in being cooperative versus competitive with another person. In accordance with evidence from evolutionary psychology as well as from developmental psychology, we argue that cooperationisasociallyrewardingprocessandisassociatedwithspecific
Robotic Thymectomy for Thymic Neoplasms

Robotic thymectomy has been well described for the management of myasthenia gravis and thymic masses. Both short- and long-term safety and efficacy have been demonstrated. Surgical approaches vary, but the technique for thymic dissection and excision is universal.
Erythropoietin and Neuroprotection in the Peripheral Nervous System: In Vivo Studies

Erythropoietin (EPO) is now known to have pleiotrophic effects outside the hematological system. Systemically delivered recombinant human EPO (rhEPO) can cross the blood brain barrier and inhibit neuronal death and inflammatory infiltrates induced by ischemia in the brain. Recent evidence also suggests that rhEPO is a potent neuroprotective agent in primary sensory neurons and peripheral glia involved in pain transmission. When L5 spinal nerve is crushed, apoptosis of sensory neurons and satellite cells occurs and is inhibited by systemic treatment with rhEPO. In addition, the neuroprotective effects of rhEPO are observed in second order neurons of the spinal dorsal horn after nerve root. In both animal models, prevention of apoptosis in neurons by rhEPO in either peripheral or central locations correlates with facilitated recoveries from neuropathic pain states. However, the in vivo effects of rhEPO are not limited to direct effects on neurons. System administration of rhEPO in animals given a chronic constriction injury to the sciatic nerve, a model known to produce the pro-inflammatory cytokine, TNF-α, at the injury site results in significant reductions in Schwann cell produced TNF-α and faster recovery from neuropathic pain states. Thus, EPO may reduce glial activation associated with axonal degeneration and pain. In rodent models of diabetes, rhEPO ameliorates both mechanical and thermal allodynia and prevents loss of epidermal unmyelinated C-fibers, suggesting a therapeutic potential for rhEPO in treating both the degenerative and painful manifestations of diabetic neuropathy. Novel EPO mimetics, including neuroactive peptides derived from prosaposin and carbamylated EPO appear to have neuroactivity without hematological side effects associated with chronic rhEPO therapy and are currently under investigation as a novel approach to treating painful peripheral neuropathies.
Edge-connectivity and edge-disjoint spanning trees

Given a graph G, for an integer [email protected]?{2,...,|V(G)|}, define @l"c(G)=min{|X|:[email protected]?E(G),@w(G-X)>=c}. For a graph G and for an integer c=1,2,...,|V(G)|-1, define, @t"c(G)[email protected]?E(G) and @w(G-X)>c|X|@w(G-X)-c, where the minimum is taken over all subsets X of E(G) such that @w(G-X)-c>0. In this paper, we establish a relationship between @l"c(G) and @t"c"-"1(G), which gives a characterization of the edge-connectivity of a graph G in terms of the spanning tree packing number of subgraphs of G. The digraph analogue is also obtained. The main results are applied to show that if a graph G is s-hamiltonian, then L(G) is also s-hamiltonian, and that if a graph G is s-hamiltonian-connected, then L(G) is also s-hamiltonian-connected.
Children engaging in storybook reading: The influence of access to print resources, opportunity, and parental interaction

Abstract Economic and social class differences in literacy-specific experiences and access to print resources have been widely documented. This study examined an intervention strategy designed to provide access to literacy materials and opportunities for parent-child storybook reading in three Head Start Centers. There were three specific objectives: (1) to examine the influence of text type (highly predictable, episodic predictable, and narrative) on patterns of interaction between parents and children; (2) to examine whether there were differences in these patterns of interaction between low proficiency and proficient parent readers; and (3) to examine gains in receptive language and concepts of print scores for children of low proficiency and proficient parent readers. Forty-one parents and their children participated in the study; 18 low proficiency parent readers and 23 proficient parent readers were involved in a 12-week book club. Results indicated that text type affected patterns of interaction and that parents' reading proficiency influenced conversational interactions, with different text types serving as a scaffold for parent-child interaction. Regardless of parental reading proficiency, however, children's receptive language and concepts of print improved significantly, providing further evidence for the importance of parental storybook reading on children's emerging literacy.
The Response of CD24 −/low /CD44 + Breast Cancer–Initiating Cells to Radiation

Background: If cancer arises and is maintained by a small population of cancer-initiating cells within every tumor, understanding how these cells react to cancer treatment will facilitate improvement of cancer treatment in the future. Cancer-initiating cells can now be prospectively isolated from breast cancer cell lines and tumor samples and propagated as mammospheres in vitro under serum-free conditions. Methods: CD24 − /low /CD44 + cancer-initiating cells were isolated from MCF-7 and MDA-MB-231 breast cancer monolayer cultures and propagated as mammospheres. Their response to radiation was investigated by assaying clonogenic survival and by measuring reactive oxygen species (ROS) levels, phosphorylation of the replacement histone H2AX, CD44 levels, CD24 levels, and Notch-1 activation using fl ow cytometry. All statistical tests were two-sided. Results: Cancer-initiating cells were more resistant to radiation than cells grown as monolayer cultures (MCF-7: monolayer cultures, mean surviving fraction at 2 Gy [SF 2Gy ] = 0.2, versus mammospheres, mean SF 2Gy = 0.46, difference = 0.26, 95% confi dence interval [CI] = 0.05 to 0.47; P = .026; MDA-MB-231: monolayer cultures, mean SF 2Gy = 0.5, versus mammospheres, mean SF 2Gy = 0.69, difference = 0.19, 95% CI = − 0.07 to 0.45; P = .09). Levels of ROS increased in both mammospheres and monolayer cultures after irradiation with a single dose of 10 Gy but were lower in mammospheres than in monolayer cultures (MCF-7 monolayer cultures: 0 Gy, mean = 1.0, versus 10 Gy, mean = 3.32, difference = 2.32, 95% CI = 0.67 to 3.98; P = .026; mammospheres: 0 Gy, mean = 0.58, versus 10 Gy, mean = 1.46, difference = 0.88, 95% CI = 0.20 to 1.56; P = .031); phosphorylation of H2AX increased in irradiated monolayer cultures, but no change was observed in mammospheres. Fractionated doses of irradiation increased activation of Notch-1 (untreated, mean = 10.7, versus treated, mean = 15.1, difference = 4.4, 95% CI = 2.7 to 6.1, P = .002) and the percentage of the cancer stem/initiating cells in the nonadherent cell population of MCF-7 monolayer cultures (untreated, mean = 3.52%, versus treated, mean = 7.5%, difference = 3.98%, 95% CI = 1.67% to 6.25%, P = .009). Conclusions: Breast cancer – initiating cells are a relatively radioresistant subpopulation of breast cancer cells and increase in numbers after short courses of fractionated irradiation. These fi ndings offer a possible mechanism for the accelerated repopulation of tumor cells observed during gaps in radiotherapy. [J Natl Cancer Inst 2006;98: 1777 – 85 ]
SSB and weighted linear utility as expected utility with suspicion

We show that a "suspicious" subjective expected utility SEU maximizer, i.e., one who treats potential consequences of states as information useful in assessing the probability of those states, may under reasonable circumstances act as though he were maximizing either weighted linear utility, or skew-symmetric bilinear SSB utility. SEU with suspicion, therefore, explains at least as many empirical violations of SEU theory as do these and similar models. We give examples to illustrate how several important types of SEU violations may seem to arise when suspicion is present.
Students At Work: Classroom Implications Of Outside Employment

With the growing population of nontraditional students, questions have been posed as to whether or not student employment results in better academic performance. This study measures the effects of employment experiences on university and classroom dynamics. Undergraduate business students from a large, private university constituted the sample. They were surveyed to determine the relationship between their university and work experiences. Findings suggest that work and educational efforts do not always compete. For many, it appears the same intangibles that propel individuals to excel in a job carries over into the academic arena. Implications for Business Education are presented.