cssi/SciSciGPT-SciSciNet huggingface dataset:
Assessing linguistic competence: when are children hard to understand?

It is argued that previous assessments of children's knowledge of the hard to see type of construction were confounded by a variety of extra-linguistic factors. Therefore, the relatively delayed age of comprehension previously reported (6½–8 years) may have been due to younger children's deficiencies in extralinguistic skills. In the present study, with these extralinguistic complications eliminated, the passing age was found to be 5 years, and even 4-year-olds evidenced considerable knowledge of the target structure. Other findings were: variation in sentence difficulty as a function of the syntactic and/or aspectual character of the verb; high test–retest reliability at all levels of performance; and a necessary-but-not-sufficient empirical relation between comprehension of the target construction and the passive. Results are discussed in terms of their implications for the acquisition of this particular structure and for the general problem of detecting linguistic competence from performance.
How multiple types of stressors impact on health.

OBJECTIVE Although many studies have focused on the relationship between stress and health, few have examined the impact of multiple types of stressors. The current study investigated the health impact of four stressors: sexual and physical abuse history, lifetime losses and traumas, turmoil in childhood family, and recent stressful life events. METHOD The sample included 239 female patients from a referral-based gastroenterology clinic. RESULTS We found that the four stressors (abuse history, lifetime traumas, turmoil in childhood family, and recent stressful life events) were related to poor health status (eg, more pain, symptoms, bed disability days, physician visits, functional disability, and psychological distress); together, these stressors accounted for 32% of the variance in overall current health. Furthermore, women who scored high on one type of stressor also tended to have experienced other types. Unlike many previous studies, we did not find that social support buffered the effects of stress. CONCLUSIONS This study provides evidence that many different types of stressors independently contribute to poor health outcome. Such findings suggest that health practitioners and researchers should question patients about histories of traumatic events, in addition to the examination of the biological aspects of illness, inasmuch as both may have notable effects on health status.
Success factors and challenges for IT capstone projects

IT capstone projects have become an essential part of the IT curriculum and give students valuable experience to work in a semester long project in a real world context. This paper investigates project success factors and challenges by examining the student feedback data we collected for the past two years. We plan to use a template analysis method to identify the success factors and challenges from the collected student feedback. Then we plan to use a survey method to study the importance of the identified factors and challenges. Our findings will provide an in-depth understanding of IT capstone projects to discover new approaches for better curriculum design and enhanced student learning experience.
Helical computed tomography for identification of crossing vessels in ureteropelvic junction obstruction-comparison with operative findings

Abstract Objectives To evaluate the use of contrast-enhanced helical computed tomography (HCT) scanning with three-dimensional reconstructions as a possible identifier of crossing vessels in ureteropelvic junction (UPJ) obstruction. Endoscopic treatment of UPJ obstruction has a success rate that approaches 90%. These results drop to 40% in the presence of crossing vessels. Unrecognized crossing vessels can also result in significant hemorrhage during endopyelotomy. The presence of crossing vessels is, for many, an indication for open or laparoscopic UPJ repair. Therefore, accurate preoperative imaging is crucial for appropriate treatment planning. Methods Our study population consisted of 18 patients evaluated and treated for UPJ obstruction at the University of Michigan Health System. These patients underwent routine contrast-enhanced preoperative HCT scanning before UPJ repair. A prior history of failed endoscopic treatment, patient preference, and HCT findings of crossing vessels were indications for open or laparoscopic repair. The imaging findings were compared with open findings during laparoscopic or open pyeloplasty. Results An HCT finding of the presence of crossing vessels was a significant positive predictor, with a value of 100%. The sensitivity in this population was 91% and the specificity was 100%. No difference was noted between the detection of arterial or venous crossing vessels. The positive predictive value was 100%, and the negative predictive value was 88%. Conclusions HCT is an accurate predictor of the presence of crossing vessels in UPJ obstruction. Because crossing vessels may have a profound impact on treatment outcome, HCT can serve as an effective, noninvasive, preoperative screening tool.
Phylogeography of the bigeye chub Hybopsis amblops (Teleostei: Cypriniformes): early Pleistocene diversification and post‐glacial range expansion

The bigeye chub, Hybopsis amblops, is a member of the Central Highlands ichthyofauna of eastern North America. Phylogenetic analyses of the H. amblops species group based on a 1059 bp fragment of the mitochondrial DNA cytochrome b gene did not recover a monophyletic group. The inclusion of Hybopsis hypsinotus in the species complex is questionable. Within H. amblops, five strongly supported clades were identified; two clades containing haplotypes from the Ozark Highlands and three clades containing haplotypes from the Eastern Highlands and previously glaciated regions of the Ohio and Wabash River drainages. Estimates of the timing of divergence indicated that prior to the onset of glaciation, vicariant events separated populations east and west of the Mississippi River. East of the Mississippi River glacial cycles associated with the blocking and rerouting of the Teays River system caused populations to be pushed southward into refugia of the upper Ohio River. Following the most recent Wisconsinan glaciation, populations expanded northward into previously glaciated regions and southward into the Cumberland River drainage. In the Ozarks, west of the Mississippi River, isolation of clades appears to be maintained by the lack of stream capture events between the upper Arkansas and the White River systems and a barrier formed by the Arkansas River.
Observations on the electron microscopic structure of insect muscle.

Abstract Four electron micrographs are reproduced. The longitudinal section of the wing muscle of the house-fly shows the absence of the series elastic component and of the A and I bands. The possible bearing on the genesis of these bands is discussed. Mitochondria of the wing muscle of the bumble-bee show a tubular inner structure, while the mitochondria of the leg muscle show laminar formations.
Association of Anxiety and ODD/CD in Children With and Without ADHD

The goal of this study is to examine levels of oppositional defiant disorder (ODD) and conduct disorder (CD) in four groups of children: attention-deficit/hyperactivity disorder (ADHD) only, anxiety only, ADHD and anxiety, and controls (i.e., non-ADHD youth). Although children with ADHD exhibit more ODD and CD than non-ADHD youth, it is unknown if anxiety is associated with increased or decreased ODD and CD in children with ADHD. We examined parent and teacher ratings of ODD and CD from the Disruptive Behavior Disorder Rating Scale in 203 school age children (ages 6-9); 70% were male, and 47% were Caucasian. Children were divided into four diagnostic groups based on ADHD and anxiety status from the Diagnostic Interview Scale for Children. According to parents, children with ADHD and anxiety had the highest levels of ODD/CD, followed by children with ADHD only (i.e., without anxiety). Children with anxiety only and controls had lowest ODD and CD scores, and these groups did not differ from each other. The same patterns were found according to teacher report, except that the anxiety only group had significantly lower levels of ODD than non-ADHD controls. Further, combined type ADHD youth with anxiety exhibited the highest levels of ODD and CD compared to all other groups. Comorbid anxiety may strengthen the association of ADHD and ODD/CD, particularly in the combined subtype. We discuss the importance of comorbid anxiety to the development of externalizing problems as well as potential explanatory factors underlying elevated ODD and CD among children with ADHD and anxiety.
The possibility that ϵ-Fe is a low temperature superconductor

Abstract It is argued, on the basis of a band calculation and of magnetic and related measurements, that ϵ-Fe may be a high pressure, low temperature superconductor. The transition temperature is estimated to be less than or equal to about 0.25 K.
Mitochondrial NADH-Ubiquinone Oxidoreductase (Complex I) EFFECT OF SUBSTRATES ON THE FRAGMENTATION OF SUBUNITS BY TRYPSIN

It has been shown that treatment of bovine mitochondrial complex I (NADH-ubiquinone oxidoreductase) with NADH or NADPH, but not with NAD or NADP, increases the susceptibility of a number of subunits to tryptic degradation. This increased susceptibility involved subunits that contain electron carriers, such as FMN and iron-sulfur clusters, as well as subunits that lack electron carriers. Results shown elsewhere on changes in the cross-linking pattern of complex I subunits when the enzyme was pretreated with NADH or NADPH (Belogrudov, G., and Hatefi, Y. (1994)Biochemistry 33, 4571–4576) also indicated that complex I undergoes extensive conformation changes when reduced by substrate. Furthermore, we had previously shown that in submitochondrial particles the affinity of complex I for NAD increases by ≥20-fold in electron transfer from succinate to NAD when the particles are energized by ATP hydrolysis. Together, these results suggest that energy coupling in complex I may involve protein conformation changes as a key step. In addition, it has been shown here that treatment of complex I with trypsin in the presence of NADPH, but not NADH or NAD(P), produced from the 39-kDa subunit a 33-kDa degradation product that resisted further hydrolysis. Like the 39-kDa subunit, the 33-kDa product bound to a NADP-agarose affinity column, and could be eluted with a buffer containing NADPH. It is possible that together with the acyl carrier protein of complex I the NADP(H)-binding 39-kDa subunit is involved in intramitochondrial fatty acid synthesis.
The determination of neon and argon in helium by atomic absorption spectrophotometry

Abstract An atomic absorption spectrophotometric technique is described for the determination of neon and argon, respectively, in helium. The accuracies obtained for nanomoles of neon and argon, respectively, were +2.1 and -1.5%. Two Geissler-type discharge tubes containing neon and argon, respectively, were used as emission sources; the absorption source was a quartz cell which contained the sample and related standards that were excited by a high-frequency oscillator. The spectral lines that were employed were neon 6402 A and argon 8115 A. Because the spectral lines used had transitions to metastable energy levels, instead of ground levels, a conventional monochromator was suitable.
Mechanism of specific membrane targeting by C2 domains: localized pools of target lipids enhance Ca2+ affinity.

The C2 domain is a ubiquitous, conserved protein signaling motif widely found in eukaryotic signaling proteins. Although considerable functional diversity exists, most C2 domains are activated by Ca2+ binding and then dock to a specific cellular membrane. The C2 domains of protein kinase Cα (PKCα) and cytosolic phospholipase A2α (cPLA2α), for example, are known to dock to different membrane surfaces during an intracellular Ca2+ signal. Ca2+ activation targets the PKCα C2 domain to the plasma membrane and the cPLA2α C2 domain to the internal membranes, with no detectable spatial overlap. It is crucial to determine how such targeting specificity is achieved at physiological bulk Ca2+ concentrations that during a typical signaling event rarely exceed 1 μM. For the isolated PKCα C2 domain in the presence of physiological Ca2+ levels, the target lipids phosphatidylserine (PS) and phosphatidylinositol-4,5-bisphosphate (PIP2) are together sufficient to recruit the PKCα C2 domain to a lipid mixture mimicking the ...
Monograph of the Neotropical Fern Genus Polybotrya (Dryopteridaceae)

The genus Polybotrya (Dryopteridaceae) includes 35 species of neotropical ferns. It is distinguished by 1) strongly dimorphic leaves with fertile leaves that resemble skeletons of the sterile, photosynthetic ones; 2) usually high-climbing stems that are covered with scales; and 3) a unique stem anatomy with 5 to 12 circularly arranged meristeles, each surrounded by a black sclerenchymatous sheath, with numerous tiny leaf traces arching between adjacent meristeles. The center of diversity of the genus is the Andes, where 23 species occur, 12 of which are endemic. The coastal mountains of southeastern Brazil are notable because they contain 5 species, all endemic. The range of Polybotrya is from Chiapas, Mexico, southward through Central America; the West Indies; northern South America southward along the Andes to Bolivia and Paraguay and eastward to the Guiana Highlands; the Amazon River basin and the Matto Grosso; and southeastern Brazil. Species of the genus typically inhabit wet, shaded, primary tropical forests from sea level to 2500 m, most often occurring at middle altitudes between 500 and 2000 m. Polybotrya is divided into three subgenera: 1) Soromanes, leaves simply pinnate and veins anastomosing; 2) Sorhifolia, leaves simply or twice pinnate and veins free, close, and parallel; and 3) Polybotrya, leaves decompound and veins free. Polybotrya cervina, a species usually included in Polybotrya, is removed to the monotypic genus Olfersia (Moran 1986). Polybotrya is related to dryopteroid genera such as Arachniodes, Cyclodium, Maxonia. Olfersia, and Polystichopsis. Carl Christensen, the father of modem fern taxonomy, observed (1916) that Polybotrya may have arisen from Maxonia because both have high-climbing stems and strongly dimorphic leaves. The morphological and anatomical evidence presented here suggests that Polybotrya may have evolved instead from a Cyclodium-like ancestor. I chose Polybotrya for study because two aspects of the genus immediately intrigued me: its strongly differentiated sterile and fertile leaves and its long, creeping hemiepiphytic stem (Fig. 1). Since these features evolved separately in unrelated fern genera, studying Polybotrya might well provide insight into broader questions of fern evolution. Polybotrya was suited to monographic study because the number of species (35), all of which are neotropical, was manageable. Finally, no previous monographic work had been done on Polybotrya and many problems of nomenclature and identification remained to be solved.
Interacting Kondo holes in a Kondo insulator

Abstract A Kondo hole is the charge neutral substitution of a rare earth ion by a non-magnetic analog. We consider the interaction between two Kondo holes in a Kondo insulator described by the non-degenerate Anderson lattice with a nearest-neighbor tight-binding conduction band on a simple cubic lattice. A Kondo hole introduces a bound state into the gap. The impurities form a strongly bound singlet if they are nearest neighbors. If they are further apart, they do not interact in the case of electron-hole symmetry. Without electron-hole symmetry non-nearest-neighbor impurities form a weakly bound spin singlet ground state, which can be overcome by moderate temperatures and/or high magnetic fields.
The molecular structure of bipyridinium tris(bipyridine)chromium(III) perchlorate

Abstract [Cr(bpy)3](ClO4)3 (bpy = 2,2′-bipyridine) cocrystallizes with bipyridinium perchlorate in the triclinic space group P 1 (No. 2), with a = 13.532(2), b = 16.596(3), c = 10.324(1) A, α = 92.16(1), β = 100.92(1), γ = 102.76(1)°, V = 2212.7 A3 and Z = 2. The structure was refined to R = 0.073 and Rw = 0.098. The cocrystallized HbpyClO4 may also have been present in earlier preparations, but could have escaped detection because of the similarity in carbon, hydrogen, nitrogen and chlorine percentages, with and without the cocrystallite.
Analysis of two-beam interferometry for bulk wave measurements.

The application of differential interferometry to bulk wave measurements can be analyzed using the kinematic formulation of the photoelastic effect. For isotropic linearly elastic materials, a standing longitudinal wave changes the indicatrix from a sphere to an ellipsoid of revolution with axes parallel and perpendicular to the direction of propagation of the acoustic wave. If the probing light is linearly polarized, differential interferometry produces a maximum signal when the polarization of the light is perpendicular to the direction of propagation. This prediction is confirmed by experiment. The case of standing transverse waves can be analyzed in a similar manner.
The appearance of α-amylase activity during gut differentiation in sand dollar plutei

Abstract α-Amylase activity appears during gut differentiation of plutei of the sand dollar Dendraster excentricus. The activity increases coincidentally with that of a β-1, 3-glucanase. The α-amylase appears to have maltase activity. Glucose in the surrounding seawater depresses the increase in β-glucanase activity but does not affect the normal α-amylase increase. This suggests that the glucose repression of β-glucanase activity may be quite specific and not result from some general effect of glucose on metabolism. Sodium dodecyl sulfate-acrylamide gel electrophoresis resolves the larval α-amylase into components of 52,000 and 76,000 molecular weight. The α-amylase from the intestines of adult sand dollars resolves as a single component of 57,000 molecular weight. The pH curves for adult and larval α-amylases are also different and it is probable that adult and larval α-amylases are different proteins.
A Level Key Infrastructure for Secure and Efficient Group Communication in Wireless Sensor Network

Group communication to and from sets of sensor nodes is an important paradigm in wireless sensor networks (WSNs). Securing this group communication is a difficult challenge given the energy-efficiency constraints posed by WSNs. In this paper, we introduce the protocol SLIMCAST, i.e. Secure Level key Infrastructure for MultiCAST and group communication, which uses level keys to provide an infrastructure that dramatically lowers the cost of nodes joining and leaving sensor groups. This level key infrastructure is shown to achieve energyefficient key updates that are localized for group multicast 1→N communication, and can be further leveraged to achieve secure group aggregation N→1 communication. Simulation results comparing the performance of SLIMCAST to traditional secure group communication protocols are presented to demonstrate SLIMCASTs energy efficiency and flexibility.
ANALYSIS OF COPPER‐BASED METALLIC ARTIFACTS BY PROMPT GAMMA‐RAY NEUTRON ACTIVATION ANALYSIS

Non-destructive analysis of the major elements in copper-alloyed artifacts by prompt gamma neutron activation analysis is reported. Copper, zinc, tin and lead were measured in several ancient Roman, Greek and Iranian objects. Good agreement was found in comparison with analysis of similar objects by destructive methods.
Calcineurin/Nfatc1 signaling links skin stem cell quiescence to hormonal signaling during pregnancy and lactation

In most tissues, the prevailing view is that stem cell (SC) niches are generated by signals from within the nearby tissue environment. Here, we define genetic changes altered in hair follicle (HF) SCs in mice treated with a potent SC activator, cyclosporine A (CSA), which inhibits the phosphatase calcineurin (CN) and the activity of the transcription factor nuclear factor of activated T cells c1 (Nfatc1). We show that CN/Nfatc1 regulates expression of prolactin receptor (Prlr) and that canonical activation of Prlr and its downstream signaling via Jak/Stat5 drives quiescence of HF SCs during pregnancy and lactation, when serum prolactin (Prl) levels are highly elevated. Using Prl injections and genetic/pharmacological loss-of-function experiments in mice, we show that Prl signaling stalls follicular SC activation through its activity in the skin epithelium. Our findings define a unique CN-Nfatc1-Prlr-Stat5 molecular circuitry that promotes persistent SC quiescence in the skin.
A switched system model for stability analysis of distributed power control algorithms for cellular communications

We examine the well known distributed power control (DPC) algorithm proposed by Foschini and Miljanic and show via simulations that it may fail to converge in the presence of time-varying channels and handoff, even when the feasibility of the power control problem is maintained at all times. Simulation results also demonstrate that the percentage of instability is a function of the variance of shadow fading, interference and the target signal to interference plus noise ratio. In order to better explain these observations and provide a systematic framework to study the stability of distributed power control algorithms in general, we present the problem in the context of switched systems, which can capture the time variations of the channel and handoffs. This formulation leads to interesting stability problems, which we address using common quadratic Lyapunov functions and M-matrices.
PREPARATION OF A FLUORESCENT ANTIBODY SPECIFIC FOR THE YEAST PHASE OF HISTOPLASMA CAPSULATUM

Abstract Kaufman, Leo (Communicable Disease Center, Atlanta, Ga.) and William Kaplan. Preparation of a fluorescent antibody specific for the yeast phase of Histoplasma capsulatum. J. Bacteriol. 82:729–735. 1961.—Rabbit anti-Histoplasma capsulatum globulin was conjugated with fluorescein isothiocyanate. This labeled antibody, in addition to staining six strains of H. capsulatum, exhibited strong cross-staining with ten strains of Blastomyces dermatitidis and numerous other species of fungi. Adsorption of the labeled antiglobulin either twice with cells of B. dermatitidis or twice with cells of Coccidioides immitis and once with cells of B. dermatitidis resulted in a good staining fluorescent antibody reagent, specific for yeast phase cells of H. capsulatum. Attempts to define the specific labeled antibody by the Ouchterlony procedure were unsuccessful. The specific conjugate did not give a complement fixation titer with yeast phase cells of B. dermatitidis or with coccidioidin. It did, however, show a 1:16 complement fixation titer with homologous yeast phase cells and a weaker reaction with histoplasmin.
A fast multiplier design using signed-digit numbers and 3-valued logic

A multiplier design using 3-valued (ternary) logic and redundant binary signed-digit (RBSD) numbers is presented. The use of 3-valued logic offers the advantage of reduced circuit complexity in terms of both transistor count and interconnections since each ternary bit can support one digit of the RBSD number system. The choice of a RBSD number system enhances the speed of multiplication by allowing carry-free addition of partial products. While the internal multiplication uses RBSD numbers, both the input operands and the output product are assumed to be in the standard two's complement form. MAGIC and SPICE software tools were used to produce VLSI design layouts and circuit simulation results. >
Mechanisms of Capsid Assembly around a Polymer

Capsids of many viruses assemble around nucleic acids or other polymers. Understanding how the properties of the packaged polymer affect the assembly process could promote biomedical efforts to prevent viral assembly or nanomaterials applications that exploit assembly. To this end, we simulate on a lattice the dynamical assembly of closed, hollow shells composed of several hundred to 1000 subunits, around a flexible polymer. We find that assembly is most efficient at an optimum polymer length that scales with the surface area of the capsid; polymers that are significantly longer than optimal often lead to partial-capsids with unpackaged polymer “tails” or a competition between multiple partial-capsids attached to a single polymer. These predictions can be tested with bulk experiments in which capsid proteins assemble around homopolymeric RNA or synthetic polyelectrolytes. We also find that the polymer can increase the net rate of subunit accretion to a growing capsid both by stabilizing the addition of new subunits and by enhancing the incoming flux of subunits; the effects of these processes may be distinguishable with experiments that monitor the assembly of individual capsids.
Colony integration and reproductive conflict in honey bees

Honey bee colonies, although highly cooperative, are composed of genetically dis- tinct individuals with differing genetic payoffs from alternative allocations of colony resources among potential reproductive individuals. Therefore conflicts among colony members are expected. This paper analyzes the empirical evidence of these conflicts in sex ratio, nepotism in queen rearing, and worker production of males. Sex ratio conflict is expected to be minimal and hard to measure in honey bees, but behavioral studies might provide insights. Nepotism in queen rearing has been investigated by several studies. The weight of the evidence suggests that weak nepotism does occur. This paper provides a reanalysis of the data of one controversial study and compares the methods and results of others. Mixed negative and positive findings may be due to certain methodological differences, or to polymorphism for this trait. Worker laying is much more common than has long been thought, but nonetheless nearly all adult drones derive from the queen, because worker policing removes nearly all worker-laid eggs. Policing, both of eggs laid and worker ovary development, also may be responsible for complete sterility of most work- ers. Thus reproductive cooperation in honey bees is underlain by a low level of active conflict. © Inra/DIB/AGIB/Elsevier, Paris
An object-oriented real-time distributed simulation of cellular phone switching system

The cellular phone network is a distributed system which is composed of three kinds of subsystems, a mobile phone unit, a base site station and a MSC (mobile switching center). A class of cellular phone switching systems, was chosen as the system to be studied. SUN workstations and the UNIX operating system with X windows have been employed as the core of the development environment. The object-oriented (OO) paradigm and C++ were chosen to develop the simulation. UICCELL was developed as an object-oriented system for cellular phone switching real-time multitasking simulation. UICCELL has been fully implemented and is currently running on an Ethernet LAN. A central monitor is created on the screen to manipulate and monitor the simulator. The graphical user interface displays the configuration of UICCELL and the status of processors, channels, etc. The current implementation contains 60 classes and about 20,000 lines of C++ code. >
A Pioneer of Hands-On Education

This biography of the physicist and science educator Frank Oppenheimer uses his crowning achievement, San Francisco's Exploratorium, as the lens through which to explore his life and work.
Effects of Representative Glucocorticoids on TNFα– and CD40L–Induced NF-κB Activation in Sensor Cells

Glucocorticoids are an important class of anti-inflammatory/immunosuppressive drugs. A crucial part of their anti-inflammatory action results from their ability to repress proinflammatory transcription factors such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) upon binding to the glucocorticoid receptor (GR). Accordingly, sensor cells quantifying their effect on inflammatory signal-induced NF-κB activation can provide useful information regarding their potencies as well as their transrepression abilities. Here, we report results obtained on their effect in suppressing both the TNFα- and the CD40L-induced activation of NF-κB in sensor cells that contain an NF-κB-inducible SEAP construct. In these cells, we confirmed concentration-dependent NF-κB activation for both TNFα and CD40L at low nanomolar concentrations (EC50). Glucocorticoids tested included hydrocortisone, prednisolone, dexamethasone, loteprednol etabonate, triamcinolone acetonide, beclomethasone dipropionate, and clobetasol propionate. They all caused significant, but only partial inhibition of these activations in concentration-dependent manners that could be well described by sigmoid response-functions. Despite the limitations of only partial maximum inhibitions, this cell-based assay could be used to quantitate the suppressing ability of glucocorticoids (transrepression potency) on the expression of proinflammatory transcription factors caused by two different cytokines in parallel both in a detailed, full dose-response format as well as in a simpler single-dose format. Whereas inhibitory potencies obtained in the TNF assay correlated well with consensus glucocorticoid potencies (receptor-binding affinities, Kd, RBA, at the GR) for all compounds, the non-halogenated steroids (hydrocortisone, prednisolone, and loteprednol etabonate) were about an order of magnitude more potent than expected in the CD40 assay in this system.
Saddle exits in optimal control problems

The purpose of this paper is to give conditions under which an optimal exit path starting from an attractor of a vector field and exiting its region of attraction passes through a saddle critical element. The control action is applied linearly with a control matrix ?(x) (not necessarily non-singular). The results thus generalize the 'mountain-pass' type theorems that say that the 'shortest way out of a valley is from the lowest mountain pass'. After a brief review of the gradient vector field case, which we give in a global setting using Morse functions, we turn to the condition of Lyapunov controllability (see Kappos [1]) as a key to the generalization of the above results to dynamics that are dissipative.
WHY PENGUIN EGGSHELLS ARE THICK

Abstract Like most other penguin species, Magellanic Penguins (Spheniscus magellanicus) are large-bodied birds that incubate their eggs for a prolonged period on hard substrates with little nesting material—all circumstances that could lead to high rates of egg breakage. However, Magellanic Penguin eggs at Punta Tombo, Argentina are seldom broken. From 1984 to 2001, only 2.6% of 10,023 eggs in our study areas broke or cracked. Most of those were broken in unusual or catastrophic events, mainly penguin fights and rainstorms. Low breakage rates appear to be attributable to thick eggshells. Shells of Magellanic Penguin eggs averaged 0.81 mm without the egg membranes—at least 56% thicker than expected for bird eggs of similar mass. The calcium required for those thick eggshells cannot be supplied by normal food intake because females lay eggs during a fasting period. It is also unlikely that sufficient skeletal calcium can be mobilized. An alternative potential calcium source is mollusk shells. To determine w...
Crosslinked liquid crystal polymers from liquid crystal monomers: Synthesis and mechanical properties

Difunctional acrylates and methacrylate monomers have been made which are high order smectic liquid crystal (or crystalline) at room temperature. This report discusses materials with the following structure: F–S–M–S–F, where F is a functional group, acrylate or methacrylate (A or M); S is a spacer (CH2)n(n), and M is a mesogen—in this case 4,4′-dioxybiphenyl (B). They are codified as BnA or BnM where n is the number of methylenes in the spacer. High conversion with high Tg can be obtained when polymerizing in the smectic state because the reactive end groups are concentrated in a small volume and can react well with little or no diffusion. B2A, B3A, B6A, B11A, and B3M were polymerized in the smectic state and compared to polymers made at temperatures where the monomers were isotropic. High conversion was obtained below final Tg—even then, probably because the polymers were ordered. All the polymers were studied by WAXD and dynamic mechanical spectroscopy. Solid-state NMR on B3A showed that there was very high conversion of the double bonds at all temperatures. B3A photopolymerized in the smectic state (60–76°C) produced a crystalline polymer with Tg = 185°C (1 Hz). When photopolymerized at 85°C, above the isotropization temperature (Ti), a poorly organized polymer was obtained with a Tg of 155°C (1 Hz). Monomers with an odd number of methylene groups as spacers were crystalline after polymerization. With an even number of methylene groups, they lost most of their crystallinity on polymerization below Ti, but retained a low order smectic structure. Similar structures were obtained with all the monomers when they were polymerized above Ti. There was little effect of polymerization temperature on Tg when the spacers had an even number of methylene groups. © 1993 John Wiley & Sons, Inc.
Identification of Mosquito Biting Deterrent Constituents From the Indian Folk Remedy Plant Jatropha curcas

An investigation of the Indian folk remedy plant Jatropha curcas L., was performed to identify the constituents responsible for the mosquito biting deterrent activity of the oil. J. curcas seed oil is burned in oil lamps in India and parts of Africa to repel biting insects, primarily mosquitoes. The seed oil was thoroughly analyzed by 1H NMR, 13C NMR, high-performance liquid chromatography-refractive index, and gas chromatography-flame ionization detection to identify the constituents in the oil. Identified constituents, both free fatty acids and triglycerides, were evaluated for activity in Aedes aegypti (L.) (Diptera: Culicidae) biting deterrent assays. Furthermore, an oil condensation trap was used to demonstrate that free fatty acids or triglycerides are partially volatilized during the combustion process. These compounds were found to be responsible for the biting deterrency of the burned oil. Specifically, oleic, palmitic, linoleic, and stearic acids were all active at 25 nmol/cm2 above that of solvent control in Ae. aegypti biting deterrent assays. Oleic, palmitic, and linoleic acids were all more active than stearic acid in the same bioassay. Evaluation of the triglycerides containing each of these fatty acids revealed that tripalmitin, tristearin, trilinolein, and triolein all demonstrated significant activity above a solvent control at 10 microg/cm2, whereas tripalmitin was the most active. Due to literature reports suggesting larvicidal activity of the oil, J. curcas seed oil and its free fatty acid constituents also were evaluated against 1-d-old Ae. aegypti larvae up to 500 ppm. Oleic acid was the only fatty acid having larvicidal activity against 1-d-old Ae. aegypti larvae, with an LD50 of 47.9 ppm.
Toward a Better Way to Measure Customer Satisfaction Levels in Public Housing: A Report from Cincinnati

This paper proposes a more reliable approach to measuring public housing customer satisfaction than has been used in the past, that is, one that (a) looks at trends in customer satisfaction rather than satisfaction at one point in time; (b) looks at different components of satisfaction; and (c) combines qualitative and quantitative information. Cross-tabular and logistic regression analysis were applied to a dataset containing approximately 1300 telephone interviews with residents of Cincinnati Metropolitan Housing Authority (CMHA) housing, interviewed over four waves (1995, 1996, 1997 and 1998). In general the survey results parallel objective evidence from agency records showing CMHA to be one of the most rapidly improving local housing authorities in the USA. Levels of housing satisfaction remained high and levels of neighbourhood satisfaction rose significantly during the period. Nevertheless, the findings highlight continuing problem areas including a high level of dissatisfaction with CMHA's repair ...
Generalized anxiety modulates frontal and limbic activation in major depression

Background: Anxiety is relatively common in depression and capable of modifying the severity and course of depression. Yet our understanding of how anxiety modulates frontal and limbic activation in depression is limited. Methods: We used functional magnetic resonance imaging and two emotional information processing tasks to examine frontal and limbic activation in ten patients with major depression and comorbid with preceding generalized anxiety (MDD/GAD) and ten non-depressed controls. Results: Consistent with prior studies on depression, MDD/GAD patients showed hypoactivation in medial and middle frontal regions, as well as in the anterior cingulate, cingulate and insula. However, heightened anxiety in MDD/GAD patients was associated with increased activation in middle frontal regions and the insula and the effects varied with the type of emotional information presented. Conclusions: Our findings highlight frontal and limbic hypoactivation in patients with depression and comorbid anxiety and indicate that anxiety level may modulate frontal and limbic activation depending upon the emotional context. One implication of this finding is that divergent findings reported in the imaging literature on depression could reflect modulation of activation by anxiety level in response to different types of emotional information.
Drylot feeding versus pasturing for milk production in dairy cattle.

Abstract Ninety-eight cows of the Holstein and Jersey breeds were paired on production criteria and used in four separate trials over a four-year period to compare milk and milk constituent yields resulting from drylot feeding or grazing of irrigated pastures. Cows in drylot received grass silage and alfalfa hay during the first three trials and haylage during the fourth trial. Pastured cows remained on excellent-quality, irrigated, grass-legume pastures except at milking time. All cows consumed the same concentrate ration twice daily during milking, the concentrate being fed in proportion to the amount of milk produced. Differences between pairmates in the production of milk, solids-not-fat, protein, and milk fat lacked statistical significance (P>.05) in all four trials. However, milk fat production during the third trial favored the pasture group. Complete lactation records (305-day, two times) showed no differences in milk constituent yields between cows in the drylot and their pairmates on pasture. However, milk production for complete records was significantly higher (P Observations on reproductive performance, udder health, and other disease problems indicated no marked differences between cows subjected to these two systems of feeding.
Friends of the Court: Examining the Influence of Amicus Curiae Participation in U.S. Supreme Court Litigation

Amicus curiae participation is a staple of interest group activity in the U.S. Supreme Court. While a reasonably large body of scholarship has accumulated regarding the effectiveness of this method of participation, little attention has been paid to examining the reasons why amicus participation might increase litigation success. In this article, I test two separate, but not mutually exclusive, theories as to why amicus briefs may be effective. The first, the affected groups hypothesis, suggests amicus briefs are influential because they signal to the Court how many groups and individuals will be potentially affected by the decision. The second, the information hypothesis, proposes that amicus briefs are effective because they provide the Court with added information that buttresses the arguments of the direct parties. When subjected to empirical verification, the results indicate that not only does amicus participation increase litigation success, but also that this influence may be best explained by the information hypothesis. Interest groups pursue their goals in a wide array of venues, including the courts. Indeed, solely within the realm of the U.S. Supreme Court, groups have numerous methods for participation, from setting up test cases to sponsoring cases that others bring to testifying at judicial confirmation hearings; some groups even hold vigils outside the marble pillars awaiting the Court’s final decisions on cases touching on group interests. However, the most common method of interest group involvement in the Supreme Court is the amicus curiae brief (Caldeira & Wright 1988; Epstein 1991). In fact, amicus briefs are filed in almost every case the Court accepts
And Justice for Some: Race, Crime, and Punishment in the US Criminal Justice System

Abstract. Criminal justice policy in the US has long been exceedingly responsive to public opinion. Unfortunately, public attitudes towards justice in the US are severely bifurcated along racial lines, such that Whites see a system that is “colour-blind” and Blacks perceive one that is severely biased against them. In this paper, we explore the magnitude of this racial cleavage and, more importantly, demonstrate how it impacts differential reactions to events (such as accusations of police brutality) and policies (such as capital punishment) in the justice domain. To the degree that elites base policies on (mainly White) majority preferences, such policies are unlikely to be responsive to the racial discrimination that is a part of the current criminal justice environment.Resume. La politique penale aux Etats-Unis repond enormement a l'opinion publique. Malheureusement, les positions populaires envers la justice americaine sont radicalement divisees suivant l'appartenance raciale. Aux yeux des Blancs, le systeme est essentiellement neutre envers les groupes raciaux differents, mais les Noirs le percoivent comme etant fortement entache de discrimination contre eux. Dans cet article, nous considerons l'etendue de cet ecart racial et, surtout, nous demontrons comment ces perceptions entrainent des reactions differentes envers les evenements (comme les accusations de brutalite policiere) et envers les politiques publiques (comme la peine capitale) dans le domaine de la justice. Dans la mesure ou les elites fondent les politiques sur les preferences de la majorite (surtout blanche), il est peu probable que ces politiques puissent remedier a la discrimination raciale qui fait partie du systeme penal actuel.
Performance considerations for parallel FFT algorithms

The authors describe parallel algorithm performance evaluation in a programming and instrumentation environment (PIE), an environment geared toward efficient parallel programming and the prediction, implementation, measurement, and evaluation of parallel fast Fourier transform (FFT) algorithms. An example of a mature technology for evaluating parallel applications is provided, emphasizing the need for integration between modeling and measurements. Performance tradeoffs for a range of parallel fast Fourier transform algorithms are explored. >
Attenuation correction strategies for multi-energy photon emitters using SPECT

The aim of this study was to investigate whether the photopeak window projections from different energy photons can be combined into a single window for reconstruction or if it is better to not combine the projections due to differences in the attenuation maps required for each photon energy. The mathematical cardiac torso (MCAT) phantom was modified to simulate the uptake of Ga-67 in the human body. Four spherical hot tumors were placed in locations which challenged attenuation correction. An analytical 3D projector with attenuation and detector response included was used to generate projection sets. Data were reconstructed using filtered backprojection (FBP) reconstruction with Butterworth filtering in conjunction with one iteration of Chang attenuation correction, and with 5 and 10 iterations of ordered-subset maximum-likelihood expectation-maximization (ML-OS) reconstruction. To serve as a standard for comparison, the projection sets obtained from the two energies were first reconstructed separately using their own attenuation maps. The emission data obtained from both energies were added and reconstructed using the following attenuation strategies: (1) the 93 keV attenuation map for attenuation correction, (2) the 185 keV attenuation map for attenuation correction, (3) using a weighted mean obtained from combining the 93 keV and 185 keV maps, and (4) an ordered subset approach which combines both energies. The central count ratio (CCR) and total count ratio (TCR) were used to compare the performance of the different strategies. Compared to the standard method, results indicate an overestimation with strategy 1, an under-estimation with strategy 2 and comparable results with strategies 3 and 4. In all strategies, the CCR's of sphere 4 (in proximity to the liver, spleen and backbone) were under-estimated, although TCR's were comparable to that of the other locations. The weighted mean and ordered subset strategies for attenuation correction were of comparable accuracy to reconstruction of the windows separately. They are recommended for multi-energy photon SPECT imaging quantitation when there is a need to combine the acquisitions of multiple windows.
Alternative states and positive feedbacks in restoration ecology

There is increasing interest in developing better predictive tools and a broader conceptual framework to guide the restoration of degraded land. Traditionally, restoration efforts have focused on re-establishing historical disturbance regimes or abiotic conditions, relying on successional processes to guide the recovery of biotic communities. However, strong feedbacks between biotic factors and the physical environment can alter the efficacy of these successional-based management efforts. Recent experimental work indicates that some degraded systems are resilient to traditional restoration efforts owing to constraints such as changes in landscape connectivity and organization, loss of native species pools, shifts in species dominance, trophic interactions and/or invasion by exotics, and concomitant effects on biogeochemical processes. Models of alternative ecosystem states that incorporate system thresholds and feedbacks are now being applied to the dynamics of recovery in degraded systems and are suggesting ways in which restoration can identify, prioritize and address these constraints.
Effects of aestivation and starvation on the neutral lipid and phospholipid content of Biomphalaria glabrata infected with Schistosoma mansoni

The effects of aestivation or starvation on the neutral lipid and phospholipid content of Biomphalaria glabrata patently infected with Schistosoma mansoni were determined by high-performance thin-layer chromatography–densitometry. Infected–aestivated snails were maintained in a moist chamber at 24 ± 1 C and a relative humidity of 98 ± 1%. Infected–starved snails were maintained in artificial spring water (ASW) at 23 ± 1 C without exogenous food. Infected snails (the controls) were maintained in ASW at 23 ± 1 C and fed lettuce ad libitum. The 3 groups were maintained in the laboratory for 7 days, and then the lipids from the digestive gland–gonad complex (DGG) were extracted and analyzed by class. Infected–aestivated snails exhibited greater mortality rate and weight loss after 7 days than did the infected–starved snails. The steryl ester concentration in the infected–starved snails was significantly increased (P = 0.010) compared with the controls but not compared with infected– aestivated snails; the con...